Diaz et al 1997 Water resources data Puerto Rico and the U.S. Virgin Islands water year 1997

Collection: Research & Technical Reports
Sub-shelf: Zenodo 8301362 — USVI freshwater gray literature
Kind: Research Report
Date: 1998-04-17
Pages: 568
Text: Native Text

Download the original document · Plain text (TXT) · Browse the archive · How this archive works

Original source: https://zenodo.org/records/8301362/files/Diaz%20et%20al%201997%20Water%20resources%20data%2C%20Puerto%20Rico%20and%20the%20U.S.%20Virgin%20Islands%2C%20water%20year%201997.pdf

SHA-256 7ce758c86416cf989687e1a71ec9ebd7d39f6557e3d8b0016dc54a111500c11b

Re-using this document

Our description, tagging, arrangement, extracted text and machine transcripts are released under CC0 1.0. We assert nothing about the document itself.

Archive identifier LF-7ce758c86416

Document text (beginning — full text at the TXT link above)

science for a changing world Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1997 St Thomas I Isla de V* Culebra Isla de Vieques PUERTO RICO St John I U. S. V I R G I N ISLANDS Saint Croix I U.S. GEOLOGICAL SURVEY WATER-DATA REPORT PR-97-1 Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands and other agencies V CALENDAR FOR WATER YEAR 1997 1996 OCTOBER S M T W T F S 12345 NOVEMBER S M T W T F S 1 2 DECEMBER S M T W T F S 1234567 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 3456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1997 JANUARY SMTWTFS 1234 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 APRIL SMTWTFS 12345 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 S M JULY T W T 12345 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 FEBRUARY SMTWTFS 1 2345678 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 MAY SMTWTFS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 AUGUST SMTWTFS 1 2 3456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2345678 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 M JUNE T W T F S 1234567 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SEPTEMBER SMTWTFS 123456 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1997 by RL. Dfaz, Z. Aquino, C. Figueroa-Alamo, R.J. Vachier, and A.V. Sanchez St Thomas I Isla de Ap Culebra Isla de Vieques PUERTO RICO St John I U. S. V I R G I N ISLANDS Saint Croix I U.S. GEOLOGICAL SURVEY WATER-DATA REPORT PR-97-1 Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands and other agencies U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director For additional information on the water resources investigation programs in Puerto Rico and the U.S. Virgin Islands write to: Chief, Caribbean District, Water Resources Division U.S. Geological Survey GSA Center, 651 Federal Drive Suite 400-15 Guaynabo, Puerto Rico 00965 Telephone: (787)749-4346 1998 PREFACE This annual hydrologic data report of Puerto Rico and the U.S. Virgin Islands is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each state, Puerto Rico, the U.S. Virgin Islands, and the other Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by state, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. The report is the culmination of a concerted effort by dedicated personnel of the U.S. Geological Survey, Water Resources Division who collected, compiled, analyzed, verified, and organized the data, and who typed, edited, and assembled the report. In addition to the authors, who had primary responsibility for assuring that the information contained herein is accurate, complete and adheres to Geological Survey policy and established guidelines, the following personnel contributed significantly to the collection, processing and tabulations of the data: Jos6 M. Agis Rafael Pena-Cortez George Arroyo Ronald T. Richard Gregory Cherry Carlos C. Rodriguez Iris M. Concepcidn Julio A. Rodriguez Israel Cruz Miguel Rodriguez Angel G. Ferrer Rafael M. Rodriguez Robert Fitzhugh Jose" Ren6 S4nchez Pedro Galindo Luis Santiago-Rivera Wilfredo Garcfa Carlos Santos Hector Guardiola Luis Soler Evelyn S. Guevara Angel Torres Sen6n Guzman-Rfos Heriberto Torres-Sierra Felipe Hernandez James Torres Sandra Lagares Jose" A. Torres Jos6 Merced Ahmed Valencia Carlos Narvaez Luis Vega Ruth I. Guzman typed the text of the report. Francisco Maldonado prepared the illustrations. This report was prepared in cooperation with agencies of the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands, and with other federal agencies under the general supervision of Rafael W. Rodriguez, District Chief, Caribbean District, San Juan, Puerto Rico. REPORT DOCUMENTATION PAGE Form Approved OMBNo. 0704-0188 Davis Highway, Suite 1204 Deluding sugge 14, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE April 17, 1998 3. REPORT TYPE AND DATES COVERED Annual - October 1, 1996 to September 30,1997 4. TITLE AND SUBTITLE Water Resources Data for Puerto Rico and the U.S. Virgin Islands Water Year 1997 6. AUTHOR(S) Pedro L. Diaz, Zaida Aquino, Carlos Figueroa-Alamo, Ricardo J. Vachier, Ana V. Sanchez 5. FUNDING NUMBERS 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U.S. Geological Survey, Water Resources Division GSA Center, 651 Federal Drive, Suite 400-15 Guaynabo, Puerto Rico 00965 8. PERFORMING ORGANIZATION REPORT NUMBER USGS-WDR-PR-97-1 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(eS) U.S. Geological Survey, Water Resources Division GSA Center, 651 Federal Drive, Suite 400-15 Guaynabo, Puerto Rico 00965 10. SPONSORING / MONITORING AGENCY REPORT NUMBER USGS-WDR-PR-97-1 11. SUPPLEMENTARY NOTES Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands, and other agencies. 12a. DISTRIBUTION/AVAILABILITY STATEMENT NO RESTRICTION ON DISTRIBUTIONS 12b. DISTRIBUTION CODE 13. ABSTRACT (Maximum 200 words) Water resources data for surface-water, quality-of-water, and ground-water records for the 1997 water year for Puerto Rico and the U.S. Virgin Islands consists of records of discharge, water quality of streams, and water levels of wells. This report contains discharge records for 74 streamflow-gaging stations; daily sediment records for 26 streamflow stations; 95 partial-record or miscellaneous streamflow stations; stage records for 16 reservoirs; water-quality records for 16 streamflow-gaging stations, 42 ungaged streamsites, 11 lake sites, 2 lagoons, and 1 bay; and water-level records for 68 observation wells. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating local and federal agencies in Puerto Rico and the U.S. Virgin Islands. 14. SUBJECT TERMS * Surface water, * Water quality, *Ground water, Aquifers, Chemical analysis, Gaging stations, Hydrologic data sediments, Streamflow, Water analysis, Water levels, Lakes 15. NUMBER OF PAGES 564 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT 20. LIMITATION OF ABSTRACT NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std 239-18 298-102 CONTENTS Preface...................................................................._^ List of surface-water and water-quality stations, in downstream order, for which records are published in this volume....................................................................................................... vii List of ground-water wells, by basin, for which records are published in this volume..................................................................................................................................................... xi List of discontinued surface-water discharge or stage-only stations....................................................................................... xiii Introduction................................................................................................................................................^ Cooperation..................................................................................................................................................................................2 Summary of hydrologic conditions..............................................................................................................................................3 Rainfall.....................................................^ Surface water........................................................................................................................................................................3 Ground water............................................................................................................................._^ Water quality.........................................................................................................................................................................8 Special networks and programs...................................................................................................................................................9 Explanation of records .................................................................................................................................................................9 Station identification numbers ............................................................................................................................................10 Downstream order system............................................................................................................................................10 Latitude-longitude system............................................................................................................................................10 Records of stage and water discharge.................................................................................................................................19 Data collection and computation.............................................................................................................................19 Data Presentation.....................................................................................................................................................20 Station manuscript ................................................................................................................................................20 Data table of daily mean values............................................................................................................................21 Statistics of monthly mean data............................................................................................................................22 Summary statistics................................................................................................................................................22 Identifying estimated daily discharge..........................................................................................................................23 Accuracy of the records...............................................................................................................................................23 Records of surface-water quality ........................................................................................................................................24 Classification of records..........................................................................................................................................................^ Arrangement of records...............................................................................................................................................24 On-site measurements and sample collection..............................................................................................................24 Water temperature......................................................................................................................................................................25 Sediment ......................................................................................................................_^ Laboratory measurements............................................................................................................................................25 Data presOTtation.......................................^^^ Remark codes...............................................................................................................................................................27 Records of ground-water levels..........................................................................................................................................27 Data collection and computation.................................................................................................................................27 Data presentation .........................................................................................................................................................28 Records of ground-water quality........................................................................................................................................28 Data collection and computation .................................................................................................................................29 Data presentation .........................................................................................................................................................29 Access to U.S. Geological Survey Water Data..........................................................................................................................29 Definition of terms.....................................................................................................................................................................30 Publications on Techniques of Water-Resources Investigations...............................................................................................40 Surface- and quality-of-water records for Puerto Rico..............................................................................................................43 Discharge at partial-record stations in Puerto Rico .................................................................................................................435 Water-quality at partial-record stations in Puerto Rico ...........................................................................................................447 Ground-water records for Puerto Rico.....................................................................................................................................463 Surface-water records for the U.S. Virgin Islands...................................................................................................................527 Ground-water records for the U.S. Virgin Islands ..................................................................................................................533 Index........................................................................................................................................................................................541 VI ILLUSTRATIONS Page Figure 1. Graph showing monthly-mean discharge of selected streams in Puerto Rico.........................................................4 2. Graph showing ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands........................................................................................................................................................7 3. Map showing location of fecal coliform bacteria concentration at sampled sites................................................. 11 4. Map showing location of fecal streptococci bacteria concentration at sampled sites............................................ 12 5. Map showing location of surface-water stations in Puerto Rico........................................................................... 13 6. Map showing location of water-quality stations in Puerto Rico............................................................................ 14 7. Map showing location of low-flow partial-record stations in North-central Puerto Rico..................................... 15 8. Map showing location of ground-water stations in Puerto Rico............................................................................ 16 9. Map showing location of surface-water stations in U.S. Virgin Islands ............................................................... 17 10. Map showing location of ground-water stations in the U.S. Virgin Islands......................................................... 18 11. Grid showing system for numbering wells and miscellaneous site (latitude and longitude)................................ 19 12. Map showing the Rio Guajataca basin.................................................................................................................. 45 13. Map showing the Rio Camuy basin...................................................................................................................... 55 14. Map showing the Rio Grande de Arecibo basin................................................................................................... 57 15. Map showing the Rio Grande de Manatf basin................................................................................................... 111 16. Map showing the Rio Cibuco basin.................................................................................................................... 131 17. Map showing the Rio de la Plata basin............................................................................................................... 139 18. Map showing the Rio Hondo to the Rfo Puerto Nuevo basins........................................................................... 165 19. Map showing the Rio Grande de Loiza basin..................................................................................................... 193 20. Map showing northeastern river basins the Rio Herrera to the Rio Ant<5n Rufz basins..................................... 307 21. Map showing southeastern river basins the Rio Humacao to the Rfo Seco basins............................................. 347 22. Map showing south coast river basins the Rfo Salinas to the Rfo Jacaguas basins............................................ 365 23. Map showing south coast river basins the Rfo Inabdn to the Rfo Loco basins ..................................................381 24. Map showing the Rfo Guanajibo basin...............................................................................................................401 25. Map showing the Rfo Yagiiez and the Rfo Grande de Anasco basins................................................................417 26. Map showing the Rfo Culebrinas basin.....................................................................:........................................429 TABLES Page Table 1. Island-wide monthly rainfall for the water year 1997 and annual averages for the 30-year reference period, 1961-90........................................................................................................................3 2. Highest water level recorded during water year 1997 and previous highest ground- - water levels at selected ground-water wells in Puerto Rico and the U.S. Virgin Islands...................................................................................................................................................................7 3. Lowest ground-water levels recorded during water year 1997 and previous lowest ground-water levels at selected wells in Puerto Rico ........................................................................................ 7 4. Surface-water quality stations in Puerto Rico with highest concentration of selected constituents during water year 1997....................................................................................................... 9 5. Factors for conversion of chemical constituents in milligrams per liter to milli- equivalents per liter............................................................................................................................................. 34 SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, y\\ FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME (Letter after station name designates type of data: (d) discharge, (c) chemical, (b) biological, (s) sediment, (p) pesticide, (e) elevation, gage heights) Station number Page RIO GUAJATACA BASIN Rio Guajataca at Lares (d,c,b)....................................................................................................... 50010500 46 Lago Guajataca at Damsite near Quebradillas (e)........................................................................ 50010800 49 Canal Principal de Diversiones at Lago Guajataca (c,b).............................................................. 50011000 50 Rio Guajataca above mouth near Quebradillas (c,b).................................................................... 50011400 52 RIO CAMUY BASIN Rio Camuy near Bayaney (d)........................................................................................................ 50014800 56 RIO GRANDE DE ARECIBO BASIN Lago Garzas near Adjuntas (e)............................................................................................. 50020100 58 Rio Grande de Arecibo near Adjuntas (c,b).................................................................................. 50020500 59 Rio Grande de Arecibo below Utuado (d,s).................................................................................. 50024950 61 Rio Grande de Arecibo near Utuado (c,b).................................................................................... 50025000 71 Rio Saliente at Coabey near Jayuya(d)................................................................................50025155 73 Rio Caonillas at Paso Palma (d,s)................................................................................................. 50026025 74 Rio Caonillas above Lago Caonillas near Jayuya (c,b)................................................................ 50026050 86 Lago Caonillas at Damsite near Utuado (e).......................................................................... 50026140 88 Rio Grande de Arecibo below Lago Dos Bocas near Florida (c,b).............................................. 50027250 89 Rfo Grande de Arecibo above Arecibo (d,s)................................................................................. 50027750 91 Rio Tanamd near Utuado (d,c,b,s)........................................................................................ 50028000 98 Rio Tanamd at Charco Hondo (d)........................................................................................ 50028400 107 Rfo Grande de Arecibo at Central Cambalache (d,c,b)................................................................ 50029000 108 RIO GRANDE DE MANATI BASIN Rfo Orocovis at Orocovis (d)................................................................................................ 50030460 112 Rfo Orocovis near Orocovis (c,b)......................................................................................... 50030700 113 Rfo Grande de Manatf near Morovis (d,c,b)................................................................................. 50031200 115 Lago El Guineo at Damsite near Villalba (e)........................................................................ 50032290 118 Lago de Matrullas at Damsite near Orocovis (e).................................................................. 50032590 119 Rfo Bauta near Orocovis (d)................................................................................................. 50034000 120 Rfo Grande de Manatf at Ciales (d).............................................................................................. 50035000 121 Rfo Grande de Manatf at Highway 149 at Ciales (c,b)................................................................. 50035500 122 Rfo Cialitos at Highway 649 at Ciales (c,b)......................................................................... 50035950 124 Rfo Grande de Manatf at Highway 2 near Manatf (d.c.b.p).......................................................... 50038100 126 LACUNA TORTUGUERO BASIN Laguna Tortuguero Outlet near Vega Baja (c,b).......................................................................... 50038200 129 RIO CIBUCO BASIN Rfo Cibuco below Corozal (d,c,b)................................................................................................ 50038320 132 Rfo Cibuco at Vega Baja (d,c,b)................................................................................................... 50039500 135 RIO DE LA PLATA BASIN Lago Carite at Gate Tower near Cayey (e)................................................................................... 50039990 140 Rfo de La Plata at Proyecto La Plata (c,b).................................................................................... 50043000 141 Rfo de La Plata at Comerio (d,s)................................................................................................... 50043800 143 Rfo de La Plata near Comerio (c.b).............................................................................................. 50044000 150 Rfo Guadiana near Naranjito (c,b)........................................................................................ 50044850 152 Lago La Plata at Damsite near Toa Alta (e)................................................................................. 50045000 154 Rfo de La Plata below La Plata Dam (d,s).................................................................................... 50045010 155 Rfo de La Plata at Highway 2 near Toa Alta (d,c,b,s,p)............................................................... 50046000 161 RIO HONDO BASIN Rfo Hondo at Flood Channel near Catano (c,b)............................................................................ 50047530 166 SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number Page RIO DE BAYAMON BASIN Rio de Bayamon at Arenas (d)...................................................................................................... 50047535 168 Rio Sabana at Vista Monte (d).............................................................................................. 50047540 169 Lago de Cidra at Damsite near Cidra (e)...................................................................................... 50047550 170 Rio de Bayam6n below Cidra Dam (d,s)...................................................................................... 50047560 171 Rio de Bayamon near Aguas Buenas (c,b)................................................................................... 50047600 178 Rio de Bayamon near Bayamon (d).............................................................................................. 50047850 180 Rio Guaynabo near Bayamon (c,b)....................................................................................... 50047990 181 Rio de Bayamon at Flood Channel at Bayam6n (c,b,p)............................................................... 50048510 183 RIO PUERTO NUEVO BASIN Rio Piedras: Lago Las Curias at Damsite near Rio Piedras(e)......................................................................... 50048680 185 Rio Piedras near Rio Piedras (c,b,p).............................................................................................50048800 186 Rio Piedras at Hato Rey (d,c,b).................................................................................................... 50049100 188 Laguna San Jose: Laguna San Jose No 2 at San Juan (c,b)....................................................................................... 50049820 191 Bahia de San Juan: Bahia de San Juan No 5 at San Juan (c,b)........,............................................................................ 50049920 192 QUEBRADA BLASINA BASIN Quebrada Blasina near Carolina (c,b)........................................................................................... 50050300 194 RIO GRANDE DE LOIZA BASIN Rio Grande de Loiza at Quebrada Arenas (d)............................................................................... 50050900 196 Quebrada Blanca at El Jagual (d,s)....................................................................................... 50051150 197 Quebrada Salvatierra near San Lorenzo (d,s)....................................................................... 50051180 204 Rio Cayaguas at Cerro Gordo (d)......................................................................................... 50051310 211 Rio Grande de Loiza at Highway 183 near San Lorenzo (d,s)..................................................... 50051800 212 Rio Turabo above Borinquen (d,s)........................................................................................ 50053025 219 Rio Grande de Loiza at Caguas (d,c,b,s)...................................................................................... 50055000 226 Rio Caguitas near Aguas Buenas (d,s).................................................................................. 50055100 235 Rio Caguitas near Caguas (d,s)............................................................................................. 50055170 242 Rio Caguitas at Villa Blanca at Caguas (d,s)........................................................................ 50055225 248 Rio Caguitas at Highway 30 at Caguas (c,b)........................................................................ 50055250 255 Rio Bairoa at Bairoa (d,s)..................................................................................................... 50055390 257 Rio Bairoa near Caguas (c,b)................................................................................................ 50055400 263 Rio Gurabo: Rio Gurabo below El Mango (d,s)........................................................................................ 50055750 265 Rio Valenciano near Juncos (d,s)..................................................................................... 50056400 272 Rio Gurabo at Gurabo (d,s)................................................................................................... 50057000 279 Rio Gurabo near Gurabo (c,b).............................................................................................. 50057025 286 Rio Canas at Rio Canas (d,s)................................................................................................ 50058350 288 Lago Loiza at Damsite near Trujillo Alto (c,b,e).......................................................................... 50059000 295 Rio Grande de Loiza below Damsite (d,s).................................................................................... 50059050 297 Rio Grande de Loiza below Trujillo Alto (c,b)............................................................................. 50059100 304 Rio Canovanas near Campo Rico (d).................................................................................... 50061800 306 RIO ESPIRITU SANTO BASIN Quebrada Sonadora near El Verde........................................................................................ 50063440 308 Rio Espfritu Santo near Rio Grande (d,c,b).................................................................................. 50063800 310 Rio Grande near El Verde (d)............................................................................................... 50064200 313 RIO MAMEYES BASIN Rio Mameyes near Sabana (d,s).................................................................................................... 50065500 314 SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, IX FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number Page RIO SABANA BASIN Rio Sabana at Sabana (d).............................................................................................................. 50067000 321 RIO FAJARDO BASIN Rio Fajardo above Fajardo (d,s).................................................................................................... 50070500 322 Rio Fajardo near Fajardo (d,c,b,p,s)............................................................................................. 50071000 333 Rio Fajardo below Fajardo (c,b)................................................................................................... 50072500 342 RIO BLANCO BASIN Quebrada Guaba near Naguabo (d)............................................................................................... 50074950 344 Rio Icacos near Naguabo (d)......................................................................................................... 50075000 345 RIO HUMACAO BASIN Rio Humacao at Las Piedras (d)................................................................................................... 50081000 348 Rio Humacao at Highway 3 at Humacao (c,b)............................................................................. 50082000 349 RIO GUAYANES BASIN Rio Guayanes at Yabucoa (c,b,p)................................................................................................. 50083500 351 Rio Guayanes above mouth at Playa de Guayanes (c,b).............................................................. 50086500 353 RIO MAUNABO BASIN Rio Maunabo at Lizas (d)............................................................................................................. 50090500 355 Rio Maunabo at Maunabo (c,b).................................................................................................... 50091000 356 RIO CHICO BASIN Rio Chico at Providencia (c,b)...................................................................................................... 50091800 358 RIO GRANDE DE PATILLAS BASIN Rio Grande de Patillas near Patillas (d,c,b).................................................................................. 50092000 360 Lago Patillas at Damsite near Patillas (e)..................................................................................... 50093045 363 RIO SALINAS BASIN Rio Lapas near Rabo del Buey (d)................................................................................................ 50100200 366 Rio Majada at La Plena (d)........................................................................................................... 50100450 367 RIO COAMO BASIN Rio Coamo at Coamo (d).............................................................................................................. 50106100 368 Rio Coamo near Coamo (c,b)....................................................................................................... 50106500 369 RIO DESCALABRADO BASIN Rio Descalabrado near Los Llanos (d).......................................................................................... 50108000 371 RIO JACAGUAS BASIN Rio Toa Vaca above Lago Toa Vaca (d,s)............................................................................ 50110900 372 Lago Guayabal at Damsite near Juana Diaz (e)............................................................................ 50111300 379 Rio Jacaguas at Juana Dfaz (d)..................................................................................................... 50111500 380 RIO INABON BASIN Rio Inabon at Real Abajo(d)........................................................................................................ 50112500 382 RIO BUCANA BASIN Rio Bucan£: Rio Cerrillos above Lago Cerrillos near Ponce (d)....................................................................... 50113800 383 Lago Cerrillos at Damsite near Ponce (e)..................................................................................... 50113950 384 Rio Cerrillos near Ponce (d,c,b).................................................................................................... 50114000 385 Rio Bucana at Hwy 14 Bridge near Ponce (d).............................................................................. 50114390 388 X SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number Page RIO PORTUGUES BASIN Rio Portugu6s near Ponce (d,c,b).................................................................................................. 50115000 389 Rio Portugu6s at Ponce (c,b,p)...................................................................................................... 50116200 392 RIO GUAYANILLA BASIN Rfo Guayanilla near Guayanilla (d).............................................................................................. 50124200 394 Rio Guayanilla at Central Rufma (c.b.p)...................................................................................... 50124700 395 RIO YAUCO BASIN Lago Lucchetti at Damsite near Yauco (e)................................................................................... 50125780 397 RIO LOCO BASIN Lago Loco at Damsite near Yauco (e).......................................................................................... 50128900 398 Rfo Loco at Gudnica (c,b,p).......................................................................................................... 50129700 399 RIO GUANAJIBO BASIN Rfo Guanajibo at Highway 119 at San German (d)...................................................................... 50131990 402 Rfo Guanajibo near San German (c,b).......................................................................................... 50133600 403 Rfo Rosario near Hormigueros (d,c,b,s)............................................................................... 50136400 405 Rfo Guanajibo near Hormigueros (d,c,b,p)................................................................................... 50138000 413 RIO YAGUEZ BASIN Rfo Yaguez near Mayaguez (c,b).................................................................................................. 50138800 418 RIO GRANDE DE ANASCO BASIN Lago Guayo at Damsite near Castaner (e)............................................................................ 50141500 420 Rfo Grande de Anasco near Lares (c,b)........................................................................................ 50143000 421 Rfo Grande de Anasco near San Sebastian (d,c,b,s)..................................................................... 50144000 423 Rfo Grande de Anasco near Anasco (c.b.p).................................................................................. 50146000 426 RIO CULEBRINAS BASIN Rfo Culebrinas near San Sebastian (c,b)....................................................................................... 50147600 430 Rfo Culebrinas at Highway 404 near Moca (d)............................................................................ 50147800 432 Rfo Culebrinas near Aguada (c,b,p).............................................................................................. 50149100 433 Discharge at partial-record stations and miscellaneous sites Low-flow partial-record stations................................................................................................................... 436 Analyses of samples collected of water-quality partial-record stations and miscellaneous sites............................................................................................................ 448 ST THOMAS, US VIRGIN ISLANDS Bonne Resolution Gut at Bonne Resolution (d)........................................................................... 50252000 528 Turpentine Run at Mount Zion (d)................................................................................................ 50274000 529 ST JOHN, US VIRGIN ISLANDS Guinea Gut at Bethany (d)............................................................................................................ 50295000 530 STCROIX, US VIRGIN ISLANDS Jolly Hill Gut at Jolly Hill (d)....................................................................................................... 50345000 531 GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED XI Page RIO GUAJATACA BASIN Well 182422067015100 Local number 165 ....................................................................................................................464 Well 182647066552400 Local number 202 ....................................................................................................................465 RIO GRANDE DE ARECIBO BASIN Well 182737066370900 Local number 204 ....................................................................................................................466 Well 182616066364100 Local number EN-1 ..................................................................................................................468 Well 182737066370900 Local number FL-1 ..................................................................................................................469 Well 182209066340600 Local number TI-1 ...................................................................................................................470 RIO GRANDE DE MANATI BASIN Well 182549066304300 Local number 166 ...................................................................................................................471 Well 182757066325600 Local number 206 ....................................................................................................................472 Well 182710066303700 Local number 207 ....................................................................................................................473 Well 182308066260400 Local number 210 ....................................................................................................................474 Well 182548066265700 Local number CS-7 ................................................................................................................475 Well 182506066280200 Local number HI-2,,,.,.,,,,.....,,,,...,.,...,,,,.,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,.476 RIO CIBUCO BASIN Well 182647066201700 Local number 70 .....,....,...,,,,,,,...,,.,,,,.,,,,,,..,,,,.,,,,.,,,,...,.,,,,,,,,,,,.,477 Well 182615066235300 Local number 211 .,,........,,,....,,,,..,,,,...,,,.,.,,,,,,.,,,,,,,,,,,,.,,,,,,,,,,,,478 Well 182515066194000 Local number 212 ,.,.,..,,,.,,,..,....,,,,...,,,,..,,...,,,,.,.,,,,,,,.,.,,,.,.,,,,,,.,,479 Well 182330066185700 Local number 213 ...,.,,.......,,,,,,,.,,.,,,...,..,.,.,,,......,,,...,,,,,,,,,,,,.,,,,,,,480 Well 182614066261500 Local number PA-2.,,,,,,,,,,,..,.,,,,,,,,,,,,,,.,,,,,,,,,..,,,,,,,,,.,,,,,,,,,481 Well 182712066251700 Local number TO-3,,,....,,,....,,,...,,,,...,,,,.,,,,,..,,,.,.,.,,,,.,,,,,,,,,,.,,,,,482 RIO DE LA PLATA BASIN Well 182530066135400 Local number 216 .,.,,,,..,.,,,,.....,,,,,,,,,,,.,,,,.,,,,,.,,,,,,..,,,,,,,,,.,,,,,483 Well 182655066142400 Local number 217 ,,,.v.,,,.......,,,,,,,,....,,,,,,.,,..,.,.,,,,,.,,,,,,,,,,,,,,,,,.,484 Well 182804066173500 Local number DA-1 ,...,.,,..,..,...,.......,,.,,.,.,,,,,.,,.,,.,,,,...,,,,,,,,,,,,,,,,,,485 Well 182620066163203 Local number HG-4 ..,,,..,,.,,,,....,,,,,,.,.,,,..,..,,.,,,,,.,,,,,..,..,,,,,,,,,,,,,486 Well 182657066162700 Local number SA-1 .,.....,,,,,..,.,,,,.,...,,,,,,,,,,,,,,,,,.,...,,,...,,,,,.,,,...,,,,487 Well 182657066162701 Local number SA-3 .,,,...,,,.,,,.,,,,..,,,.....,,.,.,,,,,,,,,,,,,,.,,,,,,,,,,..,,,,,488 Well 182548066164101 Local number MA-2,...,,,.,.,...,.,.,..,,,,...,,,,,,,,..,,,,,,,,,,,,,,,, Well 182526066165001 Local number SR-2 ,....,,,,...,,,,....,,,....,,,,,.,.,,,,.,,.,,,.,,,,..,,,,,,,,,,,,,,,490 Well 182654066150600 Local number TB-1 ,,.......,,,,,,,,,.,,,,,,,,,.,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,491 RIO HONDO TO RIO PUERTO NUEVO BASINS Well 182441066082600 Local number 219 ...,,,,,,,,,,,,,,,...,,,..,,,,,,,,,,,,,,..,,,,,,,,,,,,,,,,,,,,,492 Well 182511066045401 Local number PN-2.,,.,,,,.,,,,,.,.,,,,,,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,493 Well 182435066052700 Local number PN-5 ,.,,,,,,,.,,.,,,...,.,,,,..,,,,,,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,494 Well 182445066043401 Local number PN-6,,...,.,,,.,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,495 Well 182443066041502 Local number PN-8c ....,,,,..,,.,,,.,,,,.,,,..,.,,,..,.,,,,,,.,,..,,,,.,,,,,,,,.,,,,,496 Well 182417066042700 Local number PN-10,,,,,,,,,,,,,.,,,,,,,,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,497 Well 182349066032600 Local number PN-13 ,,,,,,,,,,,,,..,,,,..,,,,.,..,,.,..,,,,,,,,,,,,,,,,,,,,,,,,,,498 Well 182406066034700 Local number PN-19....,,,,,,,,,,,,,,,.,,,,,..,,,.,,,,,..,,,,,,,,..,,,,,,,,,,,,,,499 XII GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED-Continued Page RIO GRANDE DE LOIZA BASIN Well 181550065593200 Local number 50 ......................................................................................................................500 Well 182515065594100 Local number 222 ....................................................................................................................501 Well 181513065554601 Local number CJ-TW3B ..........................................................................................................502 Well 181352066025300 Local number CJ-TW19A........................................................................................................503 RIO HERRERA TO RIO ANTON RUIZ BASINS Well 181823065401900 Local number RF-04 ................................................................................................................504 Well 181917065382701 Local number RF-12 ................................................................................................................505 Well 182131065421100 Local number RP-04 ................................................................................................................506 Well 182138065431800 Local number RS-02................................................................................................................507 RIO HUMACAO TO RIO SECO BASINS Well 175858066100200 Local number 6 ........................................................................................................................508 Well 180415065513900 Local number 96 ......................................................................................................................509 Well 175719066085500 Local number P-13...................................................................................................................510 RIO SALINAS TO RIO JACAGUAS BASINS Well 175829066232200 Local number 87 ......................................................................................................................511 Well 180002066132200 Local number HW-TW-01 .......................................................................................................512 Well 180001066122002 Local number HW-TW-03C ....................................................................................................513 Well 175947066130601 Local number HW-TW-05B ....................................................................................................514 Well 175957066123400 Local number HW-TW-13.......................................................................................................515 Well 175903066165000 Local number PG-07................................................................................................................516 Well 175943066224800 Local number PS-07.................................................................................................................517 Well 180206066135500Local number RM-05...............................................................................................................518 Well 180104066152300 Local number RM-10...............................................................................................................519 RIO INABON TO RIO LOCO BASINS Well 180133066503300 Local number 132 ....................................................................................................................520 Well 175950066354200 Local number 141 ....................................................................................................................521 Well 180045066381600 Local Number AN-1 ................................................................................................................522 RIO GUANAJIBO BASIN Well 180132067033800 Local number 143 ....................................................................................................................523 Well 180628067084300 Local number CA-1..................................................................................................................524 RIO CULEBRINAS BASIN Well 182442067091700 Local number 200 ....................................................................................................................525 ST. CROIX, U.S. VIRGIN ISLANDS Well 174225064472000 Local number 2 ........................................................................................................................534 Well 174243064475100 Local number 3 ........................................................................................................................535 Well 174316064480800 Local number 13 ......................................................................................................................536 ST. THOMAS, U.S. VIRGIN ISLANDS Well 182038064550300 Local number 6........................................................................................................................537 Well 182038064580000 Local number 8 ........................................................................................................................538 ST. JOHN, U.S. VIRGIN ISLANDS Well 181956064464500 Local number 11 ......................................................................................................................539 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DISCONTINUED STREAMFLOW STATIONS Xflf The following continuous-record streamflow stations in Puerto Rico and the U.S. Virgin Islands have been discontinued or converted to partial-record stations. Daily streamflow or stage records were collected for the period of record shown for each station. Station Station name number 50007000 Quebrada de los Cedros near Isabela 50010600 Rio Guajataca above Lago de Guajataca 50011000 Canal Diversion Lago Guajataca 50011200 Rio Guajataca below Lago Guajataca 50011400 Rio Guajataca above mouth near Quebradillas 50013000 Rio Camuy near Lares 50014000 Rio Criminales near Lares 50014600 Rio Camuy at Tres Pueblos Sinkhole 50015700 Rio Camuy near Hatillo 50016000 Rio Camuy near Camuy 50021000 Rio Pellejas at Central Pellejas 50021050 Rio Pellejas below Central Pellejas 50021500 Rio Pellejas near Utuado 50023000 Rio Vivi near Central Pellejas 50027200 Rio Grande de Arecibo blw. Lago dos Bocas 50029000 Rfo Grande de Arecibo at Central Cambalache 50031500 Rio Sana Muerto near Orocovis 50035200 Rio Grande de Manati at Hwy 145 at Ciales 50035950 Rio Cialitos at Hwy 649 at Ciales 50038360 Rio Mavilla near Corozal 50038600 Rio Unibon near Morovis 50038700 Rio Morovis at Morovis 50038900 Rio Indio at Vega Baja 50039600 Rio Cibuco at Central San Vicente 50043200 Rio Usabon near Barranquitas 50043400 Rio Aibonito Tributary near Aibonito 50044600 Rio Guadiana near Naranjito 50044650 Quebrada del Toro near Naranjito 50044800 Quebrada Anones near Naranjito 50045700 Rio Lajas at Toa Alta 50047820 Rio de Bayam6n at Hwy 174 near Bayamon 50048000 Rio de Bayamon at Bayamon 50049000 Rio Piedras at Rio Piedras 50049310 Quebrada Josefina at Pinero Avenue 50053050 Rio Turabo at Borinquen 50054000 Quebrada de las Quebradillas near Caguas 50055650 Quebrada Caimito near Juncos 50056000 Rio Valenciano near Las Piedras 50056900 Quebrada Mamey near Gurabo 50058300 Quebrada Arena near Caguas Drainage area (mi2) 6.91 - — — - 7.62 4.68 — — - 5.46 7.89 9.55 5.66 169 200 3.68 132 17 9.51 5.29 1.26 — — 9.15 1.13 1.73 0.54 2.32 8.65 31.90 71.90 12.5 3.84 7.89 6.25 0.82 6.85 2.30 — Period of record 1970 1984-89 1970 1969-70,1984-87 1969-70,1984-89 1969-71 1969-70 1990-96 1984-96 1969-73 1968-70 1972-75 1969-71 1969-75 1970-71 1969-83 1965-70 1972 1970-82 1969-70 1969-70 1968 1963,66,71 1969-72 1968-69,71 1968-71 1971 1971 1971 1966-75 1966 1963-67 1971-82, 1987-93 1988-91 1984-90 1969-71,73 1984-87 1971 1984-92 1971 XIV WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DISCONTINUED STREAMFLOW STATIONS-Continued Station Station name number 50059000 Rio Piedras at Rio Piedras 50061300 Rio Canovanillas near Lofza 50062500 Rio Herrera near Colonia Dolores 50063300 Rio Espiritu Santo near El Verde 50063500 Quebrada Toronja at El Verde 50065700 Rio Mameyes at Hwy 191 at Mameyes 50072000 Rio Fajardo at Fajardo 50073200 Rio Daguao at Daguao 50073400 Quebrada Palma at Daguao 50074000 Rio Santiago at Naguabo 50075500 Rfo Blanco at Florida 50076000 Rfo Blanco near Florida 50077000 Rfo Blanco at Rfo Blanco 50077400 Rfo Blanco at Colonia La Fe 50078500 Rfo Anton Rufz at Central Pasto Viejo 50081500 Rfo Humacao near Humacao 50082000 Rfo Humacao at Hwy 3 at Humacao 50082200 Rfo Humacao near La Suiza 50082800 Rfo Guayan6s near Colonia Laura 50083500 Rfo Guayan6s near Yabucoa 50084000 Rfo Limones near Yabucoa 50085100 Rfo Guayan6s at Central Roig 50086100 Rfo del Ingenio at Comunas 50086500 Rfo Guayan6s at Playa Guayan<5s 50087200 Cano Santiago near Central Roig 50091000 Rfo Maunabo at Maunabo 50091200 Rfo Maunabo near Maunabo 50091400 Rfo Jacaboa near Lamboglia 50091700 Rfo Chico at Patillas 50091800 Rfo Chico at Providencia 50094200 Rfo Grande de Patillas at Patillas 50094300 Rfo Grande de Patillas at Providencia 50094400 Rfo Nigua at Pitahaya 50095200 Rfo Guamanf at Guayama 50095500 Rfo Guamanf near Guayama 50099000 Quebrada Aguas Verdes near Salinas 50106500 Rfo Coamo near Coamo 50106900 Rfo Coamo below Lago Coamo near Coamo 50107200 Rfo Coamo at mouth near Santa Isabel 50108200 Rfo Descalabrado at Las Ollas 50108500 Rfo Descalabrado near Santa Isabel 50111200 Rfo ToaVaca near Villalba 50111700 Rfo Jacaguas near Juana Dfaz 50111750 Rfo Jacaguas below Quebrada Guan£bana 50112100 Rfo Jacaguas near Arris 'rainage rea (mi ) 12.5 14.40 2.75 2.23 0.064 11.80 21.60 2.26 4.84 4.99 11.00 12.30 17.60 18.80 4.33 9.23 17.30 19.90 4.69 17.20 7.89 26.60 5.50 34.00 6.04 12.40 12.70 4.13 6.82 4.90 27.90 29.00 5.86 8.22 12.30 0.39 46.00 65.40 69.30 13.90 18.10 21.40 53.20 56.30 59.60 Period of record 1971-82,1987-93 1968-73 1968-72 1968-73 1983-96 1967-85 1960-63 1966-82 1972-77 1966-82 1966-82 1983-85 1973-77 1967-70 1968 1973 1983-85 1965-66,1969-71 1969-82 1969-71 1969-71 1965-66,1968,70 1965-66,1968-69 1965-66,1968-71 1965-71 1965,67,1969-82 1971-72 1965-73 1965,1969-72 1965,1967-69,1971 1967,1969,1971 1971 1965,1969,1970-71,1973 1969-71 1969-70 1989 1967-68,1984-85,1986 1967-68 1967-68 1965,1967-71 1966-67 1966-70 1966-68 1989 1966-67 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DISCONTINUED STREAMFLOW STATIONS-Continued XV Station Station name number 50112600 Rio Inabdn at Goto Laurel 50113100 Rio Guayo near Coto Laurel 50113500 Rio Inab6n near Arus 50114400 Rio Bucan* near Ponce 50114700 Rio BucanS near Playa de Ponce 50115900 Rio Portugu& at Hwy 14 at Ponce 50116500 Rio Portugues at Highway 2 Bypass at Ponce 50119000 Rio Matilde at Ponce 50121000 Rio Tallaboa at Penuelas 50122000 Rio Tallaboa at Tallaboa 50124000 Rfo Guayanilla nr Guayanilla 50124500 Rio Guayanilla at Guayanilla 50125900 Rfo Duey above Diversion near Yauco 50126150 Rio Yauco above Diversion Monserrate near Yauco 50128000 Rfo Yauco near Yauco 50129000 Rfo Loco near Yauco 50129500 Rfo Loco near GuSnica 50129900 Laguna Cartagena near Boquerdn 50130320 Quebrada Mamey at Joyuda 50136000 Rfo Rosario at Rosario 50141000 Rfo Yahuecas near Adjuntas 50145000 Rfo Grande de Anasco at El Espino 50147000 Rfo Culebrinas at San Sebastian 50214500 Quebrada Resaca near Monte Resaca, Culebra 50215000 Drainage Canal at Culebra Airport, Culebra 50231000 Quebrada Confresf Tributary near Isabel II, Vieques 50232000 Quebrada La Mina near Esperanza, Vieques 50233000 Quebrada Pil6n at Colonia Puerto Real, Vieques 50276000 Turpentine Run at Mariendal 50292600 Lameshur Bay Gut at Lameshur, St. John 50294000 Fish Bay Gut at Fish Bay, St. John 50295500 Cruz Bay Gut at Cruz Bay, St. John, V 50332000 River Gut at River 50333500 River Gut near Golden Grove 50333700 River Gut at Hwy 66 at Fairplanes 50334500 Bethehem Gut at Hwy 66 at Fairplanes 50337500 Gut 4.5 at Cane Valley 50348000 Salt River at Canaan 50349000 Gut 10 near Altona Drainage area (mi2) .. 11.80 30.20 25.60 28.40 __ 20.50 19.40 24.20 31.50 18.50 20.80 8.93 27.20 45.50 8.50 21.00 .. 0.38 16.40 15.40 108.00 16.70 0.23 0.08 0.28 0.68 0.67 2.97 0.38 1.48 0.09 1.42 5.40 5.89 4.11 0.2 0.36 0.13 Period of record 1967-71 1965, 1968-71 1964-65 1965-81 1964-67 1965-82 1964-65 1965-66 1959-82 1959-63 1961-69 1971-82 1977-80 1978-85 1962-64,1977-85 1963-67 1963-69 1984-86 1986-88 1975-86 1980-85 1959-66,1961-63 1960-82 1991-93 1991-93 1991-93 1991-96 1991-96 1963-69,1978-86 1992-94 1992-94 1992-93 1991-93 1990-93 1990-96 1990-96 1991-93 1991-93 1991-93 XVI THIS PAGE WAS LEFT BLANK INTENTIONALLY WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 ' INTRODUCTION The Water Resources Division of the U.S. Geological Survey, in cooperation with local and federal agencies obtains a large amount of data pertaining to the water resources of the Commonwealth of Puerto Rico and the Territory of the U.S. Virgin Islands each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the area. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data for Puerto Rico and the U.S. Virgin Islands, 1997." This report includes records on both surface and ground water. Specifically, it contains: (1) Discharge records for 74 streamflow-gaging stations, daily sediment records for 26 streamflow stations, 95 partial-record or miscellaneous streamflow stations, stage records for 16 reservoirs, and (2) water-quality records for 16 streamflow-gaging stations, and for 42 ungaged streamsites, 11 lake sites, 2 lagoons, and 1 bay; and (3) water-level records for 67 observation wells. Water-resources data for Puerto Rico for calendar years 1958-67 were released in a series of reports entitled "Water Records of Puerto Rico". Water-resources data for the U.S. Virgin Islands for the calendar years 1962-69 were released in a report entitled "Water Records of U.S. Virgin Islands." Included were records of streamflow, ground-water levels, and water- quality data for both surface and ground water. Beginning with the 1968 calendar year, surface-water records for Puerto Rico were released separately on an annual basis. Ground-water level records and water-quality data for surface and ground water were released in companion reports covering periods of several years. Data for the 1973-74 reports were published under separate covers. Water-resources data reports for 1975-76, 1977, 1978, 1979-80, 1981-82, 1983, 1984, 1985, 1986,1987, 1988, 1989, 1990, 1991, 1992, 1993,1994, 1995, and 1996 water years consist of one volume each and contain data for streamflow, water quality and ground water. Publications similar to this report are published annually by the Geological Survey for all States. These official Survey reports have an identification number consisting of the two-letter State abbreviation, the last two digits of the water year, and the volume number. For example, this volume is identified as "U.S. Geological Survey Water-Data Report PR-97-1." These water- data reports are for sale in paper copy or in microfiche by the National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia, 22161. Additional information, including current prices, for ordering specific reports may be obtained from the District Chief at the address given on back of the title page or by telephone (787) 749-4346. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 COOPERATION The U.S. Geological Survey has had cooperative agreements with organizations of the Commonwealth of Puerto Rico and the Territory of the U.S. Virgin Islands for the systematic collections of water resources data since 1958. Organizations that supplied data are acknowledged in the station descriptions. Organizations that assisted in collecting data through cooperative agreements with the Survey are: Puerto Rico Environmental Quality Board Puerto Rico Aqueduct and Sewer Authority Puerto Rico Department of Agriculture Puerto Rico Industrial Development Company Puerto Rico Department of Housing Puerto Rico Highway Authority Puerto Rico Department of Natural and Environmental Resources Puerto Rico Department of Health Puerto Rico Electric Power Authority Puerto Rico Solid Waste Management Authority Puerto Rico Legislature Puerto Rico Civil Defense U.S. Virgin Islands Department of Planning and Natural Resources Funds were also provided by the Corps of Engineers, U.S. Army, for the collection of records at six gaging stations published in this report. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 3 SUMMARY OF HYDROLOGIC CONDITIONS Rainfall Rainfall throughout Puerto Rico during the water year 1997 (October 1996 to September 1997) averaged about 77 percent of normal. During the months of October, December, and from March to September, rainfall was deficient with averages below normal that ranged from 8 to 81 percent. Significant deficient rainfall conditions were recorded during April, when recorded rainfall averaged 81 percent below normal. For the months of November, January, and February rainfall was above normal. Significant above normal rainfall conditions were recorded during January when rainfall averaged 214 percent of normal. Annual rainfall averaged about 85 percent of normal in northern Puerto Rico, 60 percent of normal in southern Puerto Rico, 76 percent of normal in western Puerto Rico, and 82 percent of normal in eastern Puerto Rico. Monthly average rainfall islandwide for the 1997 water year and for the 30-year period 1961-1990 used to define normal rainfall, as reported by the National Oceanic and Atmospheric Administration, are listed in table 1. Table 1. Islandwide monthly rainfall for the water year 1997 and annual averages for the 30-year reference period, 1961-1990 Month October November December January February March April May June July August September 1997 Water Year (inches) 4.71 7.11 3.18 6.13 3.30 2.09 0.87 3.53 2.19 4.64 5.97 4.64 30-year normal (inches) 8.29 6.55 4.38 2.86 2.52 3.02 4.46 6.96 4.99 5.08 6.89 7.14 TOTAL 48.36 63.14 Surface Water Streamflow in Puerto Rico was, in general, below normal during water year 1997, based on the index stations with monthly-mean discharges lower than the long-term monthly median flow during several months. A monthly comparison of the monthly-mean flows for the period of record at the index stations on the Rio Grande de Manatf, the Rio Fajardo, the Rio Inabdn, and the Rio Grande de Anasco are shown in figure 1. Islandwide, streamflow was below the long-term monthly median as recorded by the four index stations for the months of October and from April to July. In the north coast, the Rio Grande de Manatf index station recorded flows below the long-term monthly median during October, April to July, and September. Monthly mean flows during these months ranged from 26 to 63 percent of the long-term median of the monthly mean flows. Mean monthly flows were above normal from November to March and August. A historical maximum monthly mean flow was recorded during January with 401 percent of the long-term median. In the east coast, the index station on the Rio Fajardo, recorded monthly mean flows below the long-term median during October, December, and from April to August. Monthly mean flows during these months ranged from 45 to 94 percent of the long-term median of the monthly mean flows. The mean monthly flows were equal to the long-term monthly median during March and above normal during November, January, and September when mean monthly flows were 215,155, and 109 percent, respectively, of the long-term monthly median of the monthly mean flows. NORTH RIO GRANDE DE MANATl AT HWY 2 (50038100) 10,000 1,000 § CO ffi g m o LU O CO ONDJFMAMJJAS SOUTH RlO INABON AT REAL ABAJO (50112500) 1,000 o ONDJFMAMJJAS EAST RlO FAJARDO NEAR FAJARDO (50071000) 1,000 100 § CO cc UJ Q. UJ UJ g m o UJ O ONDJFMAMJJAS WEST RIO GRANDE DE ANASCO NEAR SAN SEBASTIAN (50144000) 1997 MONTHLY MEAN - —— 1964-96 MEDIAN OF MONTHLY-MEAN ONDJFMAMJJAS Unshaded area indicates range between highest and lowest monthly-mean discharges for the period of record to water year 1997. Figure 1 .-Monthly-mean discharge of selected streams in Puerto Rico. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 In the south coast, the Rio Inabon index station, recorded monthly mean flows below the long-term median from October to December, and from March to September. Monthly mean flows during these months ranged from 20 to 93 percent of the long-term median of the monthly mean flows. Historical minimum monthly mean flows of 2.8 and 6.2 cubic feet per second were recorded during April and September, respectively. In the west coast, the Rfo Grande de Anasco index station, recorded mean monthly flows below normal during October, April to July, and September. Monthly mean flows during these months ranged from 41 to 91 percent of the long-term median of the monthly mean flows. Mean monthly flows were above normal from November to March, and during August ranging from 109 to 217 percent of the long-term median of the monthly mean flows. A historical maximum monthly mean flow was recorded during January with 217 percent of the long-term median. Ground-Water Levels Ground-water levels in most aquifers in Puerto Rico and the U.S. Virgin Islands generally declined during water year 1997. The ground-water levels were relatively unchanged from October to January after the effects of hurricane Hortense on September 9-10,1996, and in response to high soil moisture and rainfall. From February to September, the ground-water levels declined in response to below-normal rainfall and sustained ground-water withdrawals. Record-low and record-high water levels were recorded at several observation wells in Puerto Rico and the U.S. Virgin Islands during water year 1997 (tables 2 and 3). Ground-water levels in the North Coast Limestone aquifers of Puerto Rico fluctuated from October to January in response to seasonal rainfall patterns. From February to September, the water levels declined in response to below-normal rainfall in the area. At the Sabana Hoyos index well, the ground-water level declined 2.90 ft. (fig. 2). In the South Coast aquifer of Puerto Rico, the ground-water levels generally declined in response to rainfall and streamflow patterns, irrigation, and ground-water withdrawals. The ground-water levels declined from November to September as streamflow in the area diminished and ground-water withdrawals increased for irrigation purposes. At the Alomar index well, the water level declined 3.65 ft. (fig. 2). In the U.S. Virgin Islands (St. Thomas, StCroix, and St. John) ground-water levels generally declined during water year 1997 in response to below-normal rainfall and sustained ground-water withdrawals. At the Guinea Gut observation well in St. John, U.S. Virgin Islands, the ground-water levels declined by 19.60 ft. from February to September (fig. 2). WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Table 2. Highest ground-water levels recorded during water year 1997 and previous highest ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands [PR, Puerto Rico; St.T, St. Thomas; St.C, St. Croix; mm-dd-yy, month-day-year; ft-blsd, feet below land-surface datum; mm-yy, month-year] Well name or number Manati 3 Hill 2 RF-12 Fairplains 2 VIEO-6 Kirwan Terrace Local number 166 HI-2 RF-12 2 8 Location PR PR PR St.C St.T 1997 Highest water level (ft-blsd) 22.11 267.% 2.90 19.02 14.34 Date (mm-dd-yy) 01-25-97 01-24-97 11-22-96 02-08-97 12-06-96 12-07-96 Previous highest water level (ft-blsd) 22.43 282.62 4.64 19.45 22.79 Date (mm-dd-yy) 09-20-96 09-10-96 01-15-96 11-04-89 01-21-93 Period of record (mm-yy) 01-82 to 09-97 05-96 to 09-97 08-95 to 09-97 06-83 to 09-97 10-91 to 09-97 Table 3. Lowest ground-water levels recorded during water year 1997 and previous lowest ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands [PR, Puerto Rico; mm-dd-yy, month-day-year; ft-blsd, feet below land-surface datum; mm-yy, month-year] Well name or number Encantada 1 Tiburones 1 RF-04 RF-12 RP-04 RS-02 Vivoni Col. Amistad CR-TW-9A Local number EN-1 TI-1 RF-04 RF-12 RP-04 RS-02 143 CR-TW-9A Location PR PR PR PR PR PR PR PR 1997 lowest water level (ft-blsd) 313.74 292.79 18.82 10.64 14.05 7.13 40.70 7.22 Date (mm-dd-yy) 07-05-97 07-06-97 01-17-97 07-21-97 to 07-25-97 08-21-97 08-22-97 08-21-97 07-09-97 to 07-13-97 09-26-97 08-14-97 Previous lowest water level (ft-blsd) 313.34 292.44 18.22 10.45 9.66 6.95 40.09 5.99 Date (mm-dd-yy) 08-23-96 06-05-96 05-07-96 to 05-13-96 07-07-96 07-08-96 04-26-96 04-02-96 04-03-96 04-04-96 07-21-96 07-22-96 07-28-96 05-19-93 05-20-93 Period of record (mm-yy) 08-96 to 09-97 05-96 to 09-97 08-95 to 09-97 08-95 to 09-97 08-95 to 09-97 08-95 to 09-97 10-85 to 09-97 07-92 to 09-97 27 28 29 30 ^ 31 |— October November December January February March April < 1997 HI O WELL 70, SABANA HOYOS, PUERTO RICO May June July August September CO 40 6 I HI CD HI LL. LJJ HI _l DC HII 42 44 46 WELL 87, ALOMAR WELL, PUERTO RICO October November December January February March April May June July August September 1997 WELL 11, GUINEA GUT ST. JOHN U.S. VIRGIN ISLANDS 10 20 30 l_______I I_______I October November December January February March April May June July August September 1997 Figure 2. -Ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands. 8 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Water Quality In water year 1997, the U.S. Geological Survey in cooperation with several local government agencies, collected water- quality data at 73 surface-water stations in Puerto Rico. The water-quality data collected at these stations included the major chemical constituents and several additional constituents that are listed in table 4. The highest concentration of each of these additional constituents detected during water year 1997 and the station where it was detected are summarized in table 4. Table 4. Surface-water quality stations in Puerto Rico with highest concentration of selected constituents during water year 1997 [All constituent concentrations are in milligrams per liter; MBAS, Methylene blue active substance] Station number Station name Constituent Concentration 50044850 50129700 50146000 50146000 50091800 * 50091800 50106500 50144000 50091800 Rio Guadiana near Naranjito Rio Loco at Guanica Rio Grande de Anasco near Afiasco Rio Grande de Anasco near Anasco Rio Chico at Providencia * Rio Chico at Providencia Rio Coamo near Coamo Rio Grande de Anasco near San Sebastian Rio Chico at Providencia Sulfide Boron Manganese Iron Zinc Cyanide Phenols Phenols Phenols MBAS 2.6 2.2 0.61 11 0.25 <0.010 0.09 0.09 0.09 4.8 Cyanide concentrations at all water-quality stations were below the detection limit (<0.010). The presence of high concentrations of fecal coliform (fig. 3) and fecal streptococcal (fig. 4) bacteria continued to be the principal surface-water quality problem in Puerto Rico during water year 1997. A bacteria concentration exceeding one million colonies per hundred milliliters of raw water was determined for a water sample collected at the station on San Juan Bay (50049920). This station is located in the San Juan metropolitan area, which has the highest population concentration in Puerto Rico. In addition to the effluent from the San Juan metropolitan area the streams are also receiving effluents from sewage treatment plants in the upper basin. The main sources of contamination in surface-water systems in Puerto Rico are discharges of liquid wastes from industrial and municipal sources. The highest concentration of fecal coliform and fecal streptococcal bacteria in surface waters in Puerto Rico generally occurred in streams draining from densely populated and industrialized areas. Suspended sediment concentrations were monitored at 26 stations in Puerto Rico during the 1997 water as part of the cooperative program between the U.S. Geological Survey and various Commonwealth and Federal agencies. High suspended sediment concentrations are a common problem in many streams in Puerto Rico. Most of the streams with high suspended sediment concentration were related to land use, especially urban development, agriculture, and other activities where soil movement was involved. The high suspended sediment concentrations affect the water quality for drinking water and decrease the storage capacities of reservoirs used for water supply. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 SPECIAL NETWORKS AND PROGRAMS Hydrologic Bench-Mark Network is a network of 57 sites in small drainage basins around the country whose purpose is to provide consistent data on the hydrology, including water quality, and related factors in representative undeveloped watersheds nationwide, and to provide analyses on a continuing basis to compare and contrast conditions observed in basins more obviously affected by the activities of man. National Stream Quality Accounting Network (NASQAN) is a nationwide data-collection network designed by the U.S. Geological Survey to meet many of the information needs of government agencies and other groups involved in natural or regional water-quality planning and management. The 500 or so sites on NASQAN are generally located at the downstream ends of hydrologic accounting units designated by the U.S. Geological Survey Office of Water Data Coordination in consultation with the Water Resources Council. The objectives of NASQAN are (1) to obtain information on the quality and quantity of water moving within and from the United States through a systematic and uniform process of data collection, summarization, analysis, and reporting such that the data may be used for, (2) description of the areal variability of water quality in the Nation's rivers through analysis of data from this and other programs, (3) detection of changes or trends with time in the pattern of occurrence of water-quality characteristics, and (4) providing a nationally consistent data base useful for water-quality assessment and hydrologic research. The National Trends Network (NTN) is a 150-station network for sampling atmospheric deposition in the United States. The purpose of the network is to determine the variability, both in location and in time, of the composition of atmospheric deposition, which includes snow, rain, dust particles, aerosols, and gases. The core from which the NTN was built was the already-existing deposition-monitoring network of the National Atmospheric Deposition Program (NADP). The National Water-Quality Assessment (NAWOA) Program of the U.S. Geological Survey is a long-term program with goals to describe the status and trends of water-quality conditions for a large, diverse, and geographically distributed part of the Nation's ground- and surface-water resources, and to identify, describe, and explain the major natural and human factors that affect these observed conditions and trends. Assessment activities have begun in more than one-third of the study units and ultimately will be conducted in 60 study units (major watersheds and aquifer systems) that represent a wide range of environmental settings nationwide and that account for a large percentage of the Nation's water use. A wide array of chemical constituents will be measured in ground water, surface water, streambed sediments, and fish tissues. The coordinated application of comparative hydrologic studies at a wide range of spatial and temporal scales will provide information for decision making by water-resources managers and a foundation for aggregation and comparison of findings to address water-quality issues of regional and national interest. Radiochemical Programs is a network of regularly sampled water-quality stations where samples are collected to be analyzed for radioisotopes. The streams that are sampled represent major drainage basins in the conterminous United States. Tritium Network is a network of stations which has been established to provide baseline information on the occurrence of tritium in the Nation's surface waters. In addition to the surface-water stations in the network, tritium data are also obtained at a number of precipitation stations. The purpose of the precipitation stations is to provide an estimate sufficient for hydrologic studies of the tritium input to the United States. EXPLANATION OF RECORDS The surface- and ground-water records published in this report are for the 1997 water year that began October 1, 1996 and ended September 30, 1997. A calendar of the water year is provided on the inside of the front cover. The records contain streamflow data, water-quality data for surface and ground water, and ground-water-level data. The locations of the stations and wells where the data were collected are shown in figures 3 to 10. The following sections of the introductory text are presented to provide users with a more detailed explanation of how the hydrologic data published in this report were collected, analyzed, computed, and arranged for presentation. 10 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Station Identification Numbers Each data station, whether streamsite or well, in this report is assigned a unique identification number. This number is unique in that it applies specifically to a given station and to no other. The number usually is assigned when a station is first established and is retained for that station indefinitely. The systems used by the U.S. Geological Survey to assign identification numbers for surface-water stations and for ground-water well sites differ, but both are based on geographic location. The "downstream order" system is used for regular surface-water stations and the "latitude-longitude" system is used for wells. Downstream Order System Since October 1, 1950, the order of listing hydrologic-station records in Survey reports is in a downstream direction along the main stream. All stations on a tributary entering upstream from a main-stream station are listed before that station. A station on a tributary that enters between two main-stream stations is listed between them. A similar order is followed in listing stations in first rank, second rank, and other ranks of tributaries. As an added means of identification, each hydrologic station and partial-record station has been assigned a station number. These are in the same downstream order used in this report. In assigning station numbers, no distinction is made between partial-record stations and other stations; therefore, the station number for a partial-record station indicates downstream order position in a list made up of both types of stations that may be established; hence, the numbers are not consecutive. The complete 8-digit number for each station such as 50028000, which appears just to the left of the station name, includes the 2-digit part number "50" plus the 6-digit downstream order number "028000." Latitude-Longitude System The 8-digit downstream order station numbers are not assigned to wells and miscellaneous sites where only random water-quality samples or discharge measurements are taken. The well and miscellaneous site numbering system of the U.S. Geological Survey is based on the grid system of latitude and longitude. The system provides the geographic location of the well or miscellaneous site and a unique number for each site. The number consists of 15 digits. The first 6 digits denote the degrees, minutes, and seconds of latitude, the next 7 digits denote degrees, minutes, and seconds of longitude, and the last 2 digits (assigned sequentially) identify the wells or other sites within a 1-second grid. The numbers shown in the grid correspond to the local numbers assigned to each well as visited in the field. An example is well 16 (fig. 11). 6? '15' GT'OO1 45' 30' 15' 66'dO' 45' !30' ATLANTIC OCEAN 18°30' 18°00' CARIBBEAN SEA EXPLANATION FECAL COUFORM • < 1000 • 1000-10,000 • 10,000-100,000 • 100,000-1,000,000 Figure 3.--Maximum concentration of fecal coliform bacteria at the water-quality sampling sites in Puerto Rico. 67'15' 67'00! 45' 30' 15' S6'00! 45' 65'30' 18*30' 15' 18'00* ATLANTIC OCEAN y^lr^ «* * ^ 10 20 30 KILOMETERS ! CARIBBEAN SEA 10 i 20 MILES EXPLANATION FECAL STREPTOCOCCI • < 1000 ^ 1000-10,000 V 10,000-100,000 ^ 100,000-1,000,000 Figure 4.--Maximum concentration of fecal streptococci bacteria at the water-quality sampling sites in Puerto Rico. 67'15' 67*00' 45' 30' 15' 86W 65'30V ATLANTIC OCEAN *f X 18*30' £ .^ 15' 18'OQ1 30 KILOMETERS f I 20 MILES CARIBBEAN SEA EXPLANATION A 0920 CONT1NOUS STREAMFLOW m STATION AND NUMBER 093045 LAKE-ELEVATION STATION • AND NUMBER 0564 DAILY SEDIMENT STATION ' AND NUMBER Figure 5.--Location of surface-water stations in Puerto Rico. 18*30' - 18"00! ATLANTIC OCEAN „«« ,*& , &<" -.•!*• ..a^ .i-,0 EXPLANATION QUALITY OF WATER STATIONS CARIBBEAN SEA BIOLOGICAL CHEMICAL oaso SEDIMENT (Daily) o9io SEDIMENT (Quaterty) Figure 6.--Location of water-quality stations in Puerto Rico. 67°15' 67*00' 45' 30' 15' 66*00' 45s 65*30' ATLANTIC OCEAN 18*30' Rio Cuiebring.s 1485 15' - 18 8760 7953 48750 895 047750 047810 0476 7598 043998 043950 10 20 KILOMETERS CARIBBEAN SEA 10 20 MILES EXPLANATION A LOW-FLOW PARTIAL-RECORD STATION 043850 STATION IDENTIFICATION NUMBER Figure 7.—Location of low-flow partial-record stations in northcentral Puerto Rico. (ft 67'15' 67*00' 45' 15' 66'00! 65'30' ATLANTIC OCEAN 18°30! 15' 18 V00' 10 20 10 ity»«fc> ^° 30 KILOMETERS CARIBBEAN SEA EXPLANATION 6 WELL AND WELL NUMBER 20 MILES Figure 8.--Location of ground-water stations in Puerto Rico. 17 65*G55 65W 64C50' 18*24' 18°20' 01234 KILOMETERS 01234 MILES 64"5G' 45' 64°4G! ST. JOHN 18"22' 18°18* 01234 KILOMETERS XV !!!!! ^ (___T__ |__T___| 0 1 2 3,4 MILES 45' 40' 64S35' ST. CROIX 17°45' 17S40S 012^4 KILOMETERS I 01234 MILES 3450 EXPLANATION SURFACE-WATER STATION AND NUMBER Figure 9.--Location of surface-water stations in the U.S. Virgin Islands. 18 65*G5! 18'24' 18a20' : — 65W 01234 KILOMETERS 64*50' 45! 64*40' ST. JOHN °22' 1818' 01234 KILOMETERS \ \ I \______ 0 1 2 3 , 4 MILES 64*50' 45! 64*35' ST. CROIX 17'45! 17"40! 01234 KILOMETERS EXPLANATION WELL AND WELL NUMBER 01234 MILES Figure 10.—Location of ground-water stations in the U.S. Virgin Islands. WATER RESOURCES DATA FOR PUERTO RICO AND THE ILS. VIRGIN ISLANDS, 1997 19 sr 10*0 *' — or— 10*00' I7»$J' — 134 a(| 131* \ v .'« /r •27 •74 C/ C COORDINATES FOR WELLS 27 (160160066474000) AND 74 (160136066471000) COORDINATES FOR WELLS 132 (160133066603300) AND 1S4 (160120066603200) COORDINATES FOR WELL 131 (160066066602700) COORDINATES FOR WELL 16 (176022066496600) Figure 11. --Grid shoving system for numbering veils and miscellaneous sites (latitude and longitude). Records of Stage and Water Discharge Records of stage and water discharge may be complete or partial. Complete records of discharge are those obtained using a continuous stage-recording device through which either instantaneous or mean daily discharges may be computed for any time, or any period of time, during the period of record. Complete records of lake or reservoir content, similarly, are those for which stage or content may be computed or estimated with reasonable accuracy for any time, or period of time. They may be obtained using a continuous stage-recording device, but need not be. Because daily mean discharges and end-of-day contents commonly are published for such stations, they are referred to as "daily stations." By contrast, partial records are obtained through discrete measurements without using a continuous stage-recording device and pertain only to a few flow characteristics, or perhaps only one. The nature of the partial record is indicated by table titles such as "Low-flow partial records." Records of miscellaneous discharge measurements or of measurements from special studies, such as low-flow seepage studies, may be considered as partial records, but they are presented separately in this type of report. Location of all complete-record stations for which data are given in this report are shown in figures 5 and 8. Data Collection and Computation The data obtained at a complete-record gaging station on a stream or canal consists of a continuous record of stage, individual measurements of discharge throughout a range of stages, and notations regarding factors that may affect the relationships between stage and discharge. These data, together with supplemental information, such as weather records, are used to compute daily discharges. The data obtained at a complete-record gaging station on a lake or reservoir consist of a record of stage and of notations regarding factors that may affect the relationship between stage and lake content. These data are used with stage-area and stage-capacity curves or tables to compute water-surface areas and lake storage. Continuous records of stage are obtained with analog recorders that trace continuous graphs of stage or with digital recorders that punch stage values on paper tapes at selected time intervals or electronic satellite data collector platforms that receive stage values at selected time intervals. Measurements of discharge are made with current meters using methods adapted by the Geological Survey as a result of experience accumulated since 1880. These methods are described in standard textbooks, in Water-Supply Paper 2175, and in U.S. Geological Survey Techniques of Water-Resources Investigations, Book 3, Chapter A6. 20 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 In computing discharge records, results of individual measurements are plotted against the corresponding stages, and stage-discharge relation curves are then constructed. From these curves, rating tables indicating the approximate discharge for any stage within the range of the measurements are prepared. If it is necessary to define extremes of discharge outside the range of the current-meter measurements, the curves are extended using: (1) logarithmic plotting; (2) velocity-area studies; (3) results of indirect measurements of peak discharge, such as slope-area or contracted-opening measurements, and computations of flow- over-dams or weirs; or (4) step-backwater techniques. Daily mean discharges are computed by applying the daily mean stages (gage heights) to the stage-discharge curves or tables. If the stage-discharge relation is subject to change because of frequent or continual change in the physical features that form the control, the daily mean discharge is determined by the shifting-control method, in which correction factors based on the individual discharge measurements and notes of the personnel making the measurements are applied to the gage heights before the discharges are determined from the curves or tables. This shifting-control method also is used if the stage-discharge relation is changed temporarily because of aquatic growth or debris on the control. At some stations the stage-discharge relation is affected by changing stage; at these stations the rate of change in stage is used as a factor in computing discharge. In computing records of lake or reservoir contents, it is necessary to have available from surveys, curves or tables defining the relationship of stage and contents. The application of stage to the stage-content curves or tables gives the contents from which daily, monthly or yearly changes then are determined. If the stage-content relationship changes because of deposition of sediment in a lake or reservoir, periodic surveys may be necessary to redefine it. Even when this is done, as time between the last survey increases, the contents computed may increase in error. Discharges over lake or reservoir spillways are computed from stage-discharge relationships much as other stream discharges are computed. For some gaging stations there are periods when no gage-height record is obtained, or the recorded gage height is so faulty that it cannot be used to compute daily discharge or contents. This happens when the recorder stops or otherwise fails to operate properly, intakes are plugged, the float is loose in the well, or for various other reasons. For such periods, the daily discharges are estimated from the recorded range in stage, previous or following record, discharge measurements, weather records, and comparison with other station records from the same or nearby basins. Likewise, daily contents may be estimated from operator's logs, previous or following record, inflow-outflow studies, and other information. Information explaining how estimated daily-discharge values are identified in station records is included in the next two sections, "Data Presentation" (REMARKS paragraph) and "Identifying Estimated Daily Discharge." Data Presentation Steamflow data in this report are presented in a new format that is considerably different from the format in data reports prior to the 1992 water year. The major changes are that statistical characteristics of discharge now appear in tabular summaries following the water-year data table and less information is provided in the text or station manuscript above the table. These changes represent the results of a pilot program to reformat the annual water-data report to meet current user needs and data preferences. The records published for each continuous-record surface-water discharge station (gaging station) now consist of four parts, the manuscript or station description; the data table of daily mean values of discharge for the current water year with summary data; a tabular statistical summary of monthly mean flow data for a designated period, by water year; and a summary statistics table that includes statistical data of annual, daily, and instantaneous flows as well as data pertaining to annual runoff, 7-day low-flow minimum, and flow duration. Station manuscript The manuscript provides, under various headings, descriptive information, such as station location; period of record; historical extremes outside the period of record; record accuracy; and other remarks pertinent to station operation and regulation. The following information, as appropriate, is provided with each continuous record of discharge or lake content. Comments to follow clarify information presented under the various headings of the stations descriptions. LOCATION.—Information on locations is obtained from the most accurate maps available. The location of the gage with respect to the cultural and physical features in the vicinity and with respect to the reference place mentioned in the station name is given. 21 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DRAINAGE AREA.-Drainage areas are measured using the most accurate maps available. Drainage areas are updated as better maps become available. PERIOD OF RECORD.--This indicates the period for which there are published records for the station or for an equivalent station. An equivalent station is one that was in operation at a time that the present station was not, and whose location was such that records from it can reasonable be considered equivalent with records from the present station. REVISED RECORDS.-Because of new information, published records occasionally are found to be incorrect, and revisions are printed in later reports. Listed under this heading are all the reports in which revisions have been published for the station and the water years to which the revisions apply. If a revision did not include daily, monthly, or annual figures of discharge, that fact is noted after the year dates as follows: "(M)" means that only the instantaneous maximum discharge was revised; "(m)" that only the instantaneous minimum was revised; and "(P)" that only peak discharges were revised. If the drainage area has been revised, the report in which the most recently revised figure was first published is given. GAGE.—The type of gage in current use, the datum of the current gage, and a condensed history of the types, locations, and datums of previous gages are given under this heading. REMARKS.—All periods of estimated daily-discharge record will either be identified by date in this paragraph of the station description for water-discharge stations or flagged in the daily-discharge table. (See next section, "Identifying Estimated Daily Discharge.") If a remarks statement is used to identify estimated record, the paragraph will begin with this information presented as the first entry. The paragraph is also used to present information relative to the accuracy of the records, to special methods of computations, to conditions that affect natural flow at the station and, possibly, to other pertinent items. For reservoir stations, information is given on the dam forming the reservoir, the capacity, outlet works and spillway, and purpose and use of the reservoir. COOPERATION.-Records provided by a cooperating organization or obtained for the Geological Survey by a cooperating organization are identified here. EXTREMES OUTSIDE PERIOD OF RECORD.-Included here is information concerning major floods or unusually low flows that occurred outside the stated period of record. The information may or may not have been obtained by the U.S. Geological Survey. REVISIONS.--If a critical error in published records is discovered, a revision is included in the first report published following discovery of the error. Although rare, occasionally the records of a discontinued gaging station may need revision. Because, for these stations, there would be no current or, possibly, future station manuscript published to document the revision in a "Revised Records" entry, users of data for these stations who obtained the record from previously published data reports may wish to contact the District office to determine if the published records were ever revised after the station was discontinued. Of course, if the data were obtained by computer retrieval, the data would be current and there would be no need to check because any published revision of data is always accompanied by revision of the corresponding data in computer storage. Manuscript information for lake or reservoir stations differs from that for stream stations in the nature of the "Remarks" and in the inclusion of a skeleton stage-capacity table when daily contents are given. Data table of daily mean value The daily table of discharge records for stream-gaging stations gives mean discharge for each day of the water year. In the monthly summary for the table, the line headed "TOTAL" gives the sum of the daily figures for each month; the line headed "MEAN" gives the average flow in cubic feet per second for the month; and the lines headed "MAX" and "MIN" give the maximum and minimum daily mean discharges, respectively, for each month. Discharge for the month also is usually expressed in cubic feet per second per square mile (line headed "CFSM"); or in inches (line headed "IN"); or in acre-feet (line headed" AC- FT"). Figures for cubic feet per second per square mile and runoff in inches or in acre-feet may be omitted if there is extensive regulations or diversion or if the drainage area includes large noncontributing areas. 22 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Statistics of monthly mean data A tabular summary of the mean (line headed "MEAN"), maximum (line headed "MAX"), and minimum (line headed "MIN") of monthly mean flows for each month for a designated period is provided below the mean values table. The water years of the first occurrence of the maximum and minimum monthly flow are provided immediately below those figures. The designated period will be expressed as "FOR WATER YEARS - BY WATER YEAR (WY)," and will list the first and last water years of the range of years selected from the PERIOD OF RECORD paragraph in the station manuscript. It will consist of all of the station records within the specified water years, including complete months of record for partial water years, if any, and may coincide with the period of record for the station. The water years for which the statistics are computed will be consecutive, unless a break in the station record is indicated in the manuscript. Summary statistics A table titled "SUMMARY STATISTICS" follows the statistics of monthly mean data tabulation. This table consists of four columns, with the first column containing the line headings of the statistics being reported. The table provides a statistical summary of yearly, daily, and instantaneous flows, not only for the current water year but also for the previous calendar year and for a designated period, as appropriate. The designated period selected, "WATER YEARS __-____," will consist of all of the station records within the specified water years, inclusive, including complete months of record for partial water years, if any, and may coincide with the period of record for the station. The water years for which the statistics are computed will be consecutive, unless a break in the station record is indicated in the manuscript. All of the calculations for the statistical characteristics designated ANNUAL (see line headings below), except for the "ANNUAL 7-DAY MINIMUM" statistic, are calculated for the designated period using complete water years. The other statistical characteristics may be calculated using partial water years. The date or water year, as appropriate, of the first occurrence of each statistic reporting extreme values of discharge is provided adjacent to the statistic. Repeated occurrences may be noted in the REMARKS paragraph of the manuscript or in footnotes. Because the designated period may not be the same as the station period of record published in the manuscript, occasionally the dates of occurrence listed for die daily and instantaneous extremes in the designated-period column may not be within the selected water years listed in the heading. When this occurs, it will be noted in the REMARKS paragraph or in footnotes. Selected streamflow duration curve statistics and runoff data are also given. Runoff data may be omitted if there is extensive regulation or diversion of flow in the drainage basin. The following summary statistics data, as appropriate, are provided with each continuous record of discharge. Comments to follow clarify information presented under the various line headings of the summary statistics table. ANNUAL TOTAL.--The sum of the daily mean values of discharge for the year. At some stations the annual total discharge is adjusted for reservoir storage or diversion. The adjusted figures are identified by a symbol and corresponding footnotes. ANNUAL MEAN.~The arithmetic mean of the individual daily mean discharges for the year noted or for the designated period. At some stations the yearly mean discharge is adjusted for reservoir storage or diversion. The adjusted figures are identified by a symbol and corresponding footnotes. HIGHEST ANNUAL MEAN.-The maximum annual mean discharge occurring for the designated period. LOWEST ANNUAL MEAN.-The minimum annual mean discharge occurring for the designated period. HIGHEST DAILY MEAN.-The maximum daily mean discharge for the year or for the designated period. LOWEST DAILY MEAN.-The minimum daily mean discharge for the year or for the designated period. ANNUAL 7-DAY MINIMUM.-The lowest mean discharge for 7 consecutive days for a calendar year or a water year. Note that most low-flow frequency analyses of annual 7-day minimum flows use a climatic year (April 1 - March 31). The date shown in the summary statistics table is the initial date of the 7-day period. (This value should not be confused with the 7-day 10-year low-flow statistics). 23 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 INSTANTANEOUS PEAK FLOW.-The maximum instantaneous discharge occurring for the water year or for the designated period. Note that secondary instantaneous peak discharges above a selected base discharge are stored in District computer files for stations meeting certain criteria. Those discharge values may be obtained by writing to the District Office. (See address on back of the title page of this report.) INSTANTANEOUS PEAK STAGE.~The maximum instantaneous stage occurring for the water year or for the designated period. If the dates of occurrence for the instantaneous peak flow and instantaneous peak stage differ, the REMARKS paragraph in the manuscript or a footnote may be used to provide further information. INSTANTANEOUS LOW FLOW.--The minimum instantaneous discharge occurring for the water year or for the designated period. ANNUAL RUNOFF.-Indicates the total quantity of water in runoff for a drainage area for the year. Data reports may use any of the following units of measurements in presenting annual runoff data: Acre-foot (AC-FT) is the quantity of water required to cover 1 acre to a depth of 1 foot and is equivalent to 43,560 cubic feet or about 326,000 gallons or 1,233 cubic meters. Cubic feet per second per square mile (CFSM) is the average number of cubic feet of water flowing per second from each square mile of area drained, assuming the runoff is distributed uniformly in time and area. Inches (INCHES) indicates the depth to which the drainage area would be covered if all of the runoff for given time period were uniformly distributed on it. 10 PERCENT EXCEEDS.-The discharge that is exceeded 10 percent of the time for the designated period. 50 PERCENT EXCEEDS.--The discharge that is exceeded 50 percent of the time for the designated period. 90 PERCENT EXCEEDS.~The discharge that is exceeded 90 percent of the time for the designated period. Data collected at partial-record stations follow the information for continuous-record sites. Data for partial-record discharge stations are presented in a table of discharge measurements at low-flow partial-record stations. These measurements are generally made in times of drought to give better areal coverage to those events. Those measurements and others collected for some special reason are called measurements at miscellaneous sites. Identifying Estimated Daily Discharge Estimated daily-discharge values published in the water-discharge tables are identified by flagging individual daily values with the letter symbol "e" and printing a table footnote, "e Estimated." Accuracy of the Records The accuracy of streamflow records depends primarily on: (1) The stability of the stage-discharge relation or, if the control is unstable, the frequency of discharge measurements; and (2) the accuracy of measurements of stage, measurements of discharge, and interpretation of records. The accuracy attributed to the records is indicated under "REMARKS." "Excellent" means that about 95 percent of the daily discharges are within 5 percent of the true; "good," within 10 percent; and "fair," within 15 percent. Records that do not meet the criteria mentioned, are rated "poor." Different accuracies may be attributed to different parts of a given record. Daily mean discharges in this report are given to the nearest hundredth of a cubic foot per second for values less than 1 ft3/s; to the nearest tenth between 1.0 and 10 ft3/s; to whole numbers between 10 and 1,000 ft3/s; and to 3 significant figures for more than 1,000 ftVs. The number of significant figures used is based solely on the magnitude of the discharge value. The same rounding rules apply to discharges listed for partial-record stations and miscellaneous sites. 24 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Information used in the preparation of the records in this publication, such as discharge-measurement notes, gage- height records, temperature measurements, and rating tables are on file in the Caribbean District office. Also, most of the daily mean discharges are in computer-readable form and have been analyzed statistically. Information on the availability of the unpublished information or on the results of statistical analyses of the published records may be obtained from the District office. Records of Surface-Water Quality Records of surface-water quality ordinarily are obtained at or near stream-gaging stations because interpretation of records of surface-water quality nearly always requires corresponding discharge data. Records of surface-water quality in this report may involve a variety of types of data and measurement frequencies. Classification of Records Water-quality data for surface-water sites are grouped into one of three classifications. A continuing-record station is a site where data are collected on a regularly scheduled basis. Frequency may be once or more times daily, weekly, monthly, or quarterly. A partial-record station is a site where limited water-quality data are collected systematically over a period of years. Frequency of sampling is usually less than quarterly. A miscellaneous sampling site is a location other than a continuing or partial-record station, where random samples are collected to give better areal coverage to define water-quality conditions in the river basin. A careful distinction needs to be made between "continuing records" as used in this report and "continuous recordings," which refers to a continuous graph or a series of discrete values punched at short intervals on a paper tape. Some records of water quality, such as temperature and specific conductance, may be obtained through continuous recordings; however, because of costs, most data are obtained only monthly or less frequently. Locations of stations for which records on the quality of surface water appear in this report are shown in figure 6. Arrangement of Records Water-quality records collected at a surface-water daily record station are published immediately following that record, regardless of the frequency of sample collection. Station number and name are the same for both records. Where a surface-water daily record station is not available or where the water quality differs significantly from that at the nearby surface-water station, the continuing water-quality record is published with its own station number and name in the regular downstream-order sequence. Water-quality data for partial-record stations and for miscellaneous sampling sites appear in separate tables following the table of discharge measurement at miscellaneous sites. On-site Measurements and Sample Collection In obtaining water-quality data, a major concern needs to be assuring that the data obtained represent the in situ quality of the water. To assure this, certain measurements, such as water temperature, pH, and dissolved oxygen, need to be made onsite when the samples are taken. To assure that measurements made in the laboratory also represent the in situ water, carefully prescribed procedures need to be followed in collecting the samples, in treating the samples to prevent changes in quality pending analysis, and in shipping the samples to the laboratory. Procedures for onsite measurements and for collecting, treating, and shipping samples are given in publications on "Techniques of Water-Resources Investigations," Book 1, Chap. D2; Book 3, Chap. C2; Book 5, Chap. Al, A3, and A4. Detailed information on collecting, treating, and shipping samples may be obtained from the Geological Survey District office. One sample can define adequately the water quality at a given time if the mixture of solutes throughout the stream cross section is homogeneous. However, the concentration of solutes at different locations in the cross section may vary widely with different rates of water discharge, depending on the source of material and the turbulence and mixing of the stream. Some streams must be sampled through several vertical sections to obtain a representative sample needed for an accurate mean concentration and for use in calculating load. All samples obtained for the National Stream Quality Accounting Network (see definitions) are obtained from at least several verticals. Whether samples are obtained from the centroid of flow or from several verticals, depends on flow conditions and other factors which must be evaluated by the collector. 25 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Chemical-quality data published in this report are considered to be the most representative values available for the stations listed. The values reported represent water-quality conditions at the time of sampling as much as possible, consistent with available sampling techniques and methods of analysis. In the rare case where an apparent inconsistency exists between a reported pH value and the relative abundance of carbon dioxide species (carbonate and bicarbonate), the inconsistency is the result of a slight uptake of carbon dioxide from the air by the sample between measurement of pH in the field and determination of carbonate and bicarbonate in the laboratory. For chemical-quality stations equipped with digital monitors, the records consist of daily maximum, minimum, and mean values for each constituent measured and are based upon hourly punches beginning at 0100 hours and ending at 2400 hours for the day of record. More detailed records, when available, (hourly values) may be obtained from the U.S.G.S. District office whose address is given on the back of the title page of this report. Water Temperature Water temperatures are measured at most of the water-quality stations. In addition, water temperatures are taken at time of discharge measurements for water-discharge stations. For stations where water temperatures are taken manually once or twice daily, the water temperatures are taken at about the same time each day. Large streams have a small diurnal temperature change; shallow streams may have a daily range of several degrees and may follow closely the changes in air temperature. Some streams may be affected by waste-heat discharges. At stations where recording instruments are used, either mean temperatures or maximum and minimum temperatures for each day are published. Water temperatures measured at the time of water-discharge measurements are on file in the District office. Sediment Suspended-sediment concentrations are determined from samples collected by using depth-integrating and pumping sediment samplers. Samples usually are obtained at several verticals in the cross section, or a single sample may be obtained at a fixed point and a coefficient applied to determine the mean concentration in the cross sections. During periods of rapidly changing flow or rapidly changing concentration, samples may have been collected more frequently (twice daily or hourly). The published sediment discharges for days of rapidly changing flow or concentration were computed by the subdivided-day method (time-discharge weighted average). Therefore, for those days when the published sediment discharge value differs from the value computed as the product of discharge times mean concentration times 0.0027, the reader can assume that the sediment discharge for that day was computed by the subdivided-day method. For periods when no samples were collected, daily discharges of suspended sediment were estimated on the basis of water discharge, sediment concentrations observed immediately before and after the periods, suspended-sediment loads for other periods of similar discharge, and computed by the subdivided-day method using the transport curves. At other stations, suspended-sediment samples were collected periodically at many verticals in the stream cross section. Although data collected periodically may represent conditions only at the time of observations, such data are useful in establishing seasonal relations between quality and streamflow and in predicting long-term sediment-discharge characteristics of the stream. In addition to the records of suspended-sediment discharge, records of the periodic measurements of the particle-size distribution of the suspended sediment are included for some stations. Laboratory Measurements Sediment samples, samples for biochemical-oxygen demand (BOD), samples for indicator bacteria, and daily samples for specific conductance are analyzed locally. All other samples are analyzed in the Geological Survey laboratories in Denver, Co. or Ocala, Fla. Methods used in analyzing sediment samples and computing sediment records are given in TWRI, Book 5, Chap. Cl. Methods used by the Geological Survey laboratories are given in TWRI, Book 1, Chap. D2; Book 3, Chap. C2; Book 5, Chap. Al, A3, and A4. 26 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Data Presentation For continuing-record stations, information pertinent to the history of station operation is provided in descriptive headings preceding the tabular data. These descriptive headings give details regarding location, drainage area, period of record, type of data available, instrumentation, general remarks, cooperation, and extremes for parameters currently measured daily. Tables of chemical, physical, biological, radiochemical data, and so forth, obtained at a frequency less than daily are presented first, and tables of "daily values" of specific conductance, pH, water temperature, dissolved oxygen, and suspended sediment then follow in sequence, when these parameters are studied. In the descriptive headings, if the location is identical to that of the discharge gaging station, neither the LOCATION nor the DRAINAGE AREA statements are repeated. The following information, as appropriate, is provided with each continuous-record station. Comments that follow clarify information presented under the various headings of the station description. LOCATION.~See Data Presentation under "Records of Stage and Water Discharge;" same comments apply. DRAINAGE AREA.-See Data Presentation under "Records of Stage and Water Discharge;" same comments apply. PERIOD OF RECORD.-This indicates the periods for which there are published water-quality records for the station. The periods are shown separately for records of parameters measured daily or continuously and those measured less than daily. For those measured daily or continuously, periods of record are given for the parameters individually. INSTRUMENTATION.-Information on instrumentation is given only if a water-quality monitor temperature record, sediment pumping sampler, or other sampling device is in operation at a station. REMARKS.-Remarks provide added information pertinent to the collection, analysis, or computation of the records. COOPERATION.-Records provided by a cooperating organization or obtained for the Geological Survey by a cooperating organization are identified here. EXTREMES.—Maximums and minimums are given only for parameters measured daily or more frequently. None are given for parameters measured weekly or less frequently, because the true maximums or minimums may not have been sampled. Extremes, when given, are provided for both the period of record and for the current water year. REVISIONS.~If errors in published water-quality records are discovered after publication, appropriate updates are made to the Water-Quality File in the U.S. Geological Survey's computerized data system, WATSTORE, and subsequently by monthly transfer of update transactions to the U.S. Environmental Protection Agency's STORET system. Because the usual volume of updates makes it impractical to document individual changes in the State data-report series or elsewhere, potential users of U.S. Geological Survey water-quality data are encouraged to obtain all required data from the appropriate computer file to insure the most recent updates. The surface-water-quality records for partial-record stations and miscellaneous sampling sites are published in separate tables following the table of discharge measurements at miscellaneous sites. No descriptive statements are given for these records. Each station is published with its own station number and name in the regular downstream-order sequence. 27 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Remark Codes The following remark codes may appear with the water-quality data in this report: PRINTED OUTPUT REMARK E Estimated value > Actual value is known to be greater than the value shown < Actual value is known to be less than the value shown K Results based on colony count outside the acceptance range (non-ideal colony count) L Biological organism count less than 0.5 percent (organism may be observed rather than counted) D Biological organism count equal to or greater than 15 percent (dominant) & Biological organism estimated as dominant Records of Ground-Water Levels Only ground-water level data from a basic network of observation wells are published herein. This basic network contains observation wells so located that the most significant data are obtained from the fewest wells in the most important aquifers. Data Collection and Computation Measurements of water levels are made in many types of wells under varying conditions, but the methods of measurement are standardized to the extent possible. The equipment and measuring techniques used at each observation well ensure that measurements at each well are of consistent accuracy and reliability. Each well is identified by means of (1) a 15-digit number that is based on latitude and longitude and (2) a local number that is provided for local needs. See figure 10. Water-level records are obtained from direct measurements with a steel tape or from the graph or punched tape of a water-stage recorder. The water-level measurements in this report are given in feet with reference to land-surface datum (Isd). Land-surface datum is a datum plane that is approximately at land surface at each well. If known, the elevation of the land- surface datum is given in the well description. The height of the measuring point (MP) above or below land-surface datum is given in each well description. Water levels in wells equipped with recording gages are reported for every day and as an instantaneous observation at noon. Water levels are reported to as many significant figures as can be justified by the local conditions. For example, in a measurement of a depth to water of several hundred feet, the error of determining the absolute value of the total depth to water may be a few tenths of a foot, whereas the error in determining the net change of water level between successive measurements may be only a hundredth of a few hundredths of a foot. For lesser depths to water, the accuracy is greater. Accordingly, most measurements reported to a hundredth of a foot, but some are given to a tenth of a foot or a larger unit. 28 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Data Presentation Each well record consists of three parts, the station description, the data table of water levels observed during the water year and a graph of the water levels for the current water year and other selected period. The description of the well is presented first through use of descriptive headings preceding the tabular data. The comments to follow clarify information presented under the various headings of the well description. LOCATION.-This paragraph follows the well-identification number and reports the latitude and longitude (given in degrees, minutes, and seconds); a landline location designation; the hydrologic-unit number; the distance and direction from a geographic point of reference; and the owner's name. AQUIFER.—This entry designates by name (if a name exists) and geologic age the aquifer(s) open to the well. WELL CHARACTERISTICS.--This entry describes the well in terms of depth, diameter, casing depth and/or screened interval, method of construction, use, and additional information such as casing breaks, collapsed screen, and other changes since construction. INSTRUMENTATION.-This paragraph provides information on both the frequency of measurment and the collection method used, allowing the user to better evaluate the reported water-level extremes by knowing whether they are based on weekly, monthly, or some other frequency of measurement. DATUM.—This entry describes both the measuring point and the land-surface elevation at the well. The measuring point is described physically (such as top of collar, notch in top of casing, plug in pump base and so on), and in relation to land surface (such as 1.3 ft above land-surface datum). The elevation of the land-surface datum is described in feet above (or below) sea level; it is reported with a precision depending on the method of determination. REMARKS.—This entry describes factors that may influence the water level in a well or the measurement of the water level. It should identify wells that also are water-quality observation wells, and may be used to acknowledge the assistance of local (non-Survey) observers. PERIOD OF RECORD.-This entry indicates the period for which there are published records for the well. It reports the month and year of the start of publication of water-level records by the U.S. Geological Survey and the words "to current year" if the records are to be continued into the following year. Periods for which water-level records are available, but are not published by the Geological Survey, may be noted. EXTREMES FOR PERIOD OF RECORD.-This entry contains the highest and lowest water levels of the period of published record, with respect to land-surface datum, and the dates of their occurrence. A table of water levels follows the station description for each well. Water levels are reported in feet below land- surface datum and all taped measurements of water level are listed. For wells equipped with recorders, daily values tables are published for the instantaneous water-level observation at noon. The highest and lowest water levels of the water year and their dates of occurrence are shown on a line below the table. Because all values are not published for wells with recorders, the extremes may be values that are not listed in the table. Missing records are indicated by dashes in place of the water level. A hydrograph for a selected period of record follows each water-level table. Records of Ground-Water Quality Records of ground-water quality in this type of report differ from other types of records in that for most sampling sites they consist of only one set of measurements for the water year. The quality of ground water ordinarily changes only slowly; therefore, for most general purposes one annual sampling, or only a few samples taken at infrequent intervals during the year, is sufficient. Frequent measurement of the same constituents is not necessary unless one is concerned with a particular problem, such as monitoring for trends in nitrate concentration. In the special cases where the quality of ground water may change more rapidly, more frequent measurements are made to identify the nature of the changes. 29 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Data Collection and Computation The records of ground-water quality in this report were obtained mostly as a part of special studies in specific areas. Consequently, a number of chemical analyses are presented for some counties but none are presented for others. As a result, the records for this year, by themselves, do not provide a balanced view of ground-water quality Statewide. Such a view can be attained only by considering records for this year in context with similar records obtained for these and other counties in earlier years. Most methods for collecting and analyzing water samples are described in the "U.S. Geological Survey Techniques of Water-Resources Investigations" manuals listed on a following page. The values reported in this type of report represent water- quality conditions at the time of sampling as much as possible, consistent with available sampling techniques and methods of analysis. All samples are obtained by trained personnel. The wells sampled are pumped long enough to assure that the water collected comes directly from the aquifer and has not stood for a long time in the well casing where it would have been exposed to the atmosphere and to the material, possibly metal, comprising the casings. Data Presentation The records of ground-water quality, when available, are published in a section titled QUALITY OF GROUND WATER immediately following the ground-water level records. Data for quality of ground water are listed alphabetically by County, and are identified by well number. The prime identification number for wells sampled is the 15-digit number derived from the latitude-longitude locations. No descriptive statements are given for ground-water-quality records; however, the well number, depth of well, date of sampling, and other pertinent data are given in the table containing the chemical analyses of the ground water. The REMARK codes listed for surface-water-quality records are also applicable to ground-water-quality records. ACCESS TO U.S. GEOLOGICAL SURVEY WATER DATA The U.S. Geological Survey provides near real-time stage and discharge data for many of the gaging stations equipped with the necessary telemetry and historic daily-mean and peak-flow discharge data for most current or discontinued gaging stations through the world wide web (WWW). These data may be accessed at http://water.usgs.gov Some water-quality and ground-water data also are available through the WWW. In addition, data can be provided in various machine-readable formats on magnetic tape or 3-1/2 inch floppy disk. Information about the availability of specific types of data or products, and user charges, can be obtained locally from each of the Water Resources Division District Offices (see address on the back of the title page). 30 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DEFINITION OF TERMS Terms related to streamflow, water-quality, and other hydrologic data as used in this report, are defined below. See also the table for converting inch- pound units to the International System of units (SI) on the inside of the back cover. Acre-foot (AC-FT, acre-ft) is the quantity of water required to cover 1 acre to a depth of 1 foot and is equal to about 326,000 gallons or 1,233 cubic meters. Adenosine triphosphate (ATP) is an organic, phosphate-rich, compound important in the transfer of energy in organisms. Its central role in living cells makes it an excellent indicator of the presence of living material in water. A measure of ATP therefore provides a sensitive and rapid estimate of biomass. ATP is reported in micrograms per liter of the original water sample. Algae growth potential (AGP) is the maximum algal dry weight biomass that can be produced in a natural water sample under standardized laboratory conditions. The growth potential is the algal biomass present a stationary phase and is expressed as milligrams dry weight of algae produced per liter of sample. Aquifer is a geologic formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs. Artesian means confined and is used to describe a well in which the water level stands above the top of the aquifer, tapped by the well. A flowing artesian well is one in which the water level is above the land surface. Bacteria are microscopic unicellular organisms, typically spherical, rodlike, or spiral and threadlike in shape, often clumped into colonies. Some bacteria cause disease, while others perform an essential role in nature in the recycling of materials; for example, by decomposing organic matter into a form available for reuse by plants. Total coliform bacteria are a particular group of bacteria that are used as indicators of possible sewage pollution. They are characterized as aerobic or facultative anaerobic, gram-negative, nonspore-forming, rod-shaped bacteria which ferment lactose with gas formation within 48 hours at 35 °C. In the laboratory these bacteria are defined as all the organisms which produce colonies with a golden-green metallic sheen within 24 hours when incubated at 35°C ± 1.0°C on M-Endo medium (nutrient medium for bacterial growth). Their concentrations are expressed as number of colonies per 100 mL of sample. 31 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Fecal coliform bacteria are bacteria that are present in the intestines or feces of warm-blooded animals. They are often used as indicators of the sanitary quality of the water. In the laboratory they are defined as all organisms which produce blue colonies within 24 hours when incubated at 44.5°C ± 0.2'C on M-FC medium (nutrient medium for bacterial growth). Their concentrations are expressed as number of colonies per 100 mL of sample. Fecal streptococcal bacteria are bacteria found also in intestines of warm-blooded animals. Their presence in water is considered to verify fecal pollution. They are characterized as Gram-positive, cocci bacteria which are capable of growth in brain-heart infusion broth. In the laboratory they are defined as all the organisms which produce red or pink colonies within 48 hours at 35'C ± 1.0'C on KF-streptococcus medium (nutrient medium for bacterial growth). Their concentrations are expressed as number of colonies per 100 mL of sample. Bed material is the unconsolidated material of which a streambed, lake, pond, reservoir, or estuary bottom is composed. Biochemical oxygen demand (BOD) is a measure of the quantity of dissolved oxygen, in milligrams per liter, necessary for the decomposition of organic matter by microorganisms, such as bacteria. Biomass is the amount of living matter present at any given time, expressed as the mass per unit area or volume of habitat. Ash mass is the mass or amount of residue present after the residue from the dry mass determination has been ashed in a muffle furnace at a temperature of 500'C for 1 hour. The ash mass values of zooplankton and phytoplankton are expressed in grams per cubic meter (g/m3), and periphyton and benthic organisms in grams per square meter (g/m2). Dry mass refers to the mass of residue present after drying in an oven at 105°C for zooplankton and periphyton, until the mass remains unchanged. This mass represents the total organic matter, ash and sediment, in the sample. Dry-mass values are expressed in the same units as ash mass. Organic mass or volatile mass of the living substance is the difference between the dry mass and the ash mass and represents the actual matter. The organic mass is expressed in the same units as for ash and dry mass. Wet mass is the mass of living matter plus contained water. Bottom material: See Bed material. Cells/volume refers to the number of cells of any organism which is counted by using a microscope and grid or counting cell. Many planktonic organisms are multicelled and are counted according to the number of contained cells per sample, usually milliliters (mL) or liters (L). Chemical oxygen demand (COD) is a measure of the chemically oxidizable material in the water, and furnishes an approximation of the amount of organic and reducing material present. The determined value may correlate with natural water color or with carbonaceous organic pollution from sewage or industrial wastes. Chlorophyll refers to the green pigments of plants. Chlorophyll a and fe are the two most common green pigments in plants. Color unit is produced by one milligram per liter of platinum in the form of the chloroplatinate ion. Color is expressed in units of the platinum-cobalt scale. Contents is the volume of water in a reservoir or lake. Unless otherwise indicated, volume is computed on the basis of a level pool and does not include bank storage. 32 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Control designates a feature downstream from the gage that determines the stage-discharge relation at the gage. This feature may be a natural constriction of the channel, an artificial structure, or a uniform cross section over a long reach of the channel. Control structure as used in this report is a structure on a stream or canal that is used to regulate the flow or stage of the stream or to prevent the intrusion of salt water. Cubic foot per second (ft3/s) is the rate of discharge representing a volume of 1 cubic foot passing a given point during 1 second and is equivalent to 7.48 gallons per second or 448.8 gallons per minute or 0.02832 cubic meters per second. Cubic foot per second-day (ft3/s/day) is the volume of water represented by a flow of 1 cubic foot per second for 24 hours. It is equivalent to 86,400 cubic feet, approximately 1.9835 acre-feet, about 646,000 gallons, or 2,445 cubic meters. Cubic feet per second per square mile (CFSM) is the average number of cubic feet of water flowing per second from each square mile of area drained, assuming that the runoff is distributed uniformly in time and area. Discharge is the volume of water (or more broadly, volume of fluid plus suspended sediment), that passes a given point within a given period of time. Instantaneous discharge is the discharge at a particular instant of time. Mean discharge (MEAN) is the arithmetic mean of individual daily mean discharges during a specific period. Annual 7-day minimum is the lowest mean discharge for 7 consecutive days for a calendar year or a water year. Note that most low-flow frequency analyses of annual 7-day minimum flows use a climatic year (April 1 - March 31). The date shown in the summary statistics table is the initial date of the 7-day period. (This value should not be confused with the 7-day 10-year low-flow statistic.) Dissolved refers to that material in a representative water sample which passes through a 0.45 um membrane filter. This is a convenient operational definition used by Federal agencies that collect water data. Determinations of "dissolved" constituents are made on subsamples of the filtrate. Dissolved-solids concentration of water is determined either analytically by the "residue-on-evaporation" method, or mathematically by totaling the concentrations of individual constituents reported in a comprehensive chemical analysis. During the analytical determination of dissolved solids, the bicarbonate (generally a major dissolved component of water) is converted to carbonate. Therefore, in the mathematical calculations of dissolved-solids concentration, the bicarbonate value, in milligrams per liter, is multiplied by 0.492 to reflect the change. Diversity index is a numerical expression of evenness of distribution of aquatic organisms. The formula for diversity index is: __ s d = -111og2 1 n n Where ni is the number of individuals per taxon, n is the total number of individuals, and s is the total number of taxa in the sample of the community. Diversity index values range from zero, when all the organisms in the sample are the same, to some positive number, when some or all of the organisms in the sample are different. Drainage area of a stream at a specified location is that area, measured in a horizontal plane, enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into the stream above the specified point. Figures of drainage area given herein include all closed basins, or noncontribution areas, within the area unless otherwise noted. 33 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Drainage basin is a part of the surface of the earth that is occupied by a drainage system, which consists of a surface stream or a body of impounded surface water together with all tributary surface streams and bodies of impounded surface water. Gage height (gh) is the water-surface elevation referred to some arbitrary gage datum. Gage height is often used interchangeably with the more general term "stage," although gage height is more appropriate when used with a reading on a gage. Gaging station is a particular site on a stream, canal, lake, or reservoir where systematic observations of hydrologic data are obtained. Ground-water station is a well at which observations of ground-water level are made, either continuously by recorder, or periodically by hand. In addition, various chemical or physical parameters may be obtained, usually on a periodic basis. Hardness of water is a physical-chemical characteristic that is commonly recognized by the increased quantity of soap required to produce lather. It is attributable to the presence of alkaline earths (principally calcium and magnesium) and is expressed as equivalent calcium carbonate (CaCO3). Hydrologic Bench-Mark Network is a network in small drainage basins around the country whose purpose is to provide consistent data on the hydrology, including water quality, and related factors in representative undeveloped watersheds nationwide, and to provide analyses on a continuing basis to compare and contrast conditions observed in basins more obviously affected by the activities of man. Hydrologic unit is a geographic area representing part or all of a surface drainage basin or distinct hydrologic feature as delineated by the Office of Water Data Coordination on the State Hydrologic Unit Maps; each hydrologic unit is identified by an eight-digit number. Land-surface datum (LSD) is a datum plane that is approximately at land surface at each ground-water observation well. Measuring point (MP) is an arbitrary permanent reference point from which the distance to the water surface in a well is measured to obtain the water level. Metamorphic stage refers to the stage of development that an organism exhibits during its transformation from an immature form to an adult form. This developmental process exists for most insects, and the degree of difference from the immature stage to the adult form varies from relatively slight to pronounced, with many intermediates. Examples of metamorphic stages of insects are egg-larva-adult or egg-nymph-adult. Methylene blue active substances (MBAS) are apparent detergents. The determination depends on the formation of a blue color when methylene blue dye reacts with synthetic anionic detergent compounds. Micrograms per gram (fig/g) is a unit expressing the concentration of a chemical element as the mass (micrograms) of the element per unit mass (gram) of material analyzed. Micrograms per liter (fiG/L, ug/L) is a unit expressing the concentration of chemical constituents in solution as mass (micrograms) of solute per unit volume (liter) of water. One thousand micrograms per liter is equivalent to one milligram per liter. Milligrams per liter (MG/L, mg/L) is a unit for expressing the concentration of chemical constituents in solution. Milligrams per liter represent the mass of solute per unit volume (liter) of water. Concentration of suspended sediment also is expressed in mg/L, and is based on the mass of sediment per liter of water-sediment mixture. Conversion of chemical concentrations in Mg/L to milliequivalents per liter can be done by using the factors in table 6. 3 4 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Table 5. Factors for conversion of chemical constituents in milligrams per liter to milliequivalents per liter Ion Multiply by Ion Multiply bv Aluminum (Al+3)* ................ Ammonia as NH4+1 .............. Barium (Ba+2) ....................... Bicarbonate (HCO3-1)........... Bromide (Br-1)....................... Calcium (Ca+2)...................... Carbonate (CO3-2)................. Chloride(Cl-l)....................... Chromium (Cr+6)* ................ Cobalt (Co+2)* ...................... Copper (Cu+2)* ..................... Cyanide(CN-l)...................... Fluoride(F-l)......................... Hydrogen (H+l)..................... Hydroxide (OH-1).................. 0.11119 .05544 .01456 .01639 .01251 .04990 .03333 .02821 .11539 .03394 .03148 .03844 .05264 .99209 .05880 Iodide (1-1 .............................. Iron (Fe+3) ............................. Lead (Pb+2) ........................... Lithium (Li+1) ....................... Magnesium (Mg+2) ............... Manganese (Mn+2)*.. ............ Nickel (Ni+2). ....... ................. Nitrate (N03-1)....................... Nitrite (NO2-1 )...................... Phosphate (PO4-3). ................ Potassium (K+l) .................... Sodium (NA+1). .................... Strontium (Sr+2) .................... Sulfate (SO4-2). ................. .... Zinc (Zn+2)*. ......................... 0.00788 .05372 .00965 .14411 .08226 .03640 .03406 .01613 .02174 .03159 .02557 .04350 .02283 .02082 .03060 "Constituent reported in micrograms per liter; multiply by factor and divide results by 1,000. National Stream Quality Accounting Network (NASQAN) is a nationwide data-collection network designed by the U.S. Geological Survey to meet many of the information needs of government agencies and other groups involved in natural or regional water-quality planning and management. The 500 or so sites in NASQAN are generally located at the downstream ends of hydrologic accounting units designated by the U.S. Geological Survey office of Water Data Coordination in consultation with the Water Resources Council. The objectives of NASQAN are (1) to obtain information on the quality and quantity of water moving within and from the United States through a systematic and uniform process of data collection, summarization, analysis, and reporting such that the data may be used for, (2) description of the areal variability of water quality in the Nation's rivers through analysis of description of the areal variability of water quality in the Nation's rivers through analysis of data from this and other programs, (3) detection of changes or trends with time in the pattern of occurrence of water-quality characteristics, and (4) providing a nationally consistent data base useful for water-quality assessment and hydrologic research. National Trends Network (NTN) is a network for sampling atmospheric deposition in the United States. The purpose of the network is to determine the variability, both in location and in time, of the composition of atmospheric deposition, which includes snow, rain, dust particles, aerosols, and gases. The core from which the NTN was built was the already-existing deposition-monitoring network of the National Atmospheric Deposition Program (NADP). Organism is any living entity. Organism count/area refers to the number of organisms collected and enumerated in a sample and adjusted to the number per unit area habitat, usually square meters (m2), acres, or hectare. Periphyton, benthic organisms, and macrophytes are expressed in these terms. Organism count/volume refers to the number of organisms collected and enumerated in a sample and adjusted to the number per sample volume, usually milliliters (mL) or liters (L). Numbers of planktonic organisms can beexpressed in these terms. Total organism count is the total number of organisms collected and enumerated in any particular sample. Parameter Code is a 5-digit number used in the U.S. Geological Survey computerized data system, WATSTORE, to uniquely identify a specific constituent. The codes used in WATSTORE are the same as those used in the U.S. Environmental Protection Agency data system, STORET. The Environmental Protection Agency assigns and approves all requests for new codes. Partial-record station is a particular site where limited streamflow and/or water-quality data are collected systematically over a period of years for use in hydrologic analyses. 35 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Particle-size is the diameter, in millimeters (mm), of a particle determined by either sieve or sedimentation methods. Sedimentation methods (pipet, bottom-withdrawal tube, visual-accumulation tube) determine fall diameter of particles in either distilled water (chemically dispersed) or in native water (the river water at the time and point of sampling). Particle-size classification used in this report agrees with recommendations made by the American Geophysical Union Subcommittee on Sediment Terminology. The classification is as follows: Classification Size (mm) Method of analysis Clay...... 0.00024 - 0.004 Sedimentation Silt...... .004 - .062 Sedimentation Sand...... .062 - 2.0 Sedimentation or sieve Gravel.... 2.0 -64.0 Sieve The particle-size distributions given in this report are not necessarily representative of all particles in transport in the stream. Most of the organic matter is removed and the sample is subjected to mechanical and chemical dispersion before analysis in distilled water. Chemical dispersion is not used for native water analysis. Percent composition is a unit for expressing the ratio of a particular part of a sample or population to the total sample or population, in terms of types, numbers, mass or volume. Periphyton is the assemblage of microorganisms attached to and living upon submerged solid surfaces. While primarily consisting of algae, they also include bacteria, fungi, protozoa, rotifers, and other small organisms. Pesticides are chemical compounds used to control undesirable organisms. Major categories of pesticides include insecticides, miticides, fungicides, herbicides, and rodenticides. Picocurie (PC, pCi) is one trillionth (1 X 10-12) of the amount of ratioactivity represented by a curie (Ci). A curie is the amount of radioactivity that yields 3.7 x 10'° radioactive disintegrations per second. A picocurie yields 2.22 dpm (disintegrations per minute). Plankton is the community of suspended, floating, or weakly swimming organisms that live in the open water of lakes and rivers. Phvtoplankton is the plant part of the plankton. They are usually microscopic and their movement is subject to the water currents. Phvtoplankton growth is dependent upon solar radiation and nutrient substances. Because they are able to incorporate as well as release materials to the surrounding water, the phytoplankton have a profound effect upon the quality of the water. They are the primary food producers in the aquatic environment, and are commonly known as algae. Blue-green algae are a group of phytoplankton organisms having a blue pigment, in addition to the green pigment called chlorophyll. Blue-green algae often cause nuisance conditions in water. Diatoms are the unicellular or colonial algae having a siliceous shell. Their concentrations are expressed as number of cells per milliliter (cells/mL) of sample. Green algae have chlorophyll pigments similar in color to those of higher green plants. Some forms produce algae mats or floating "moss" in lakes. Their concentrations are expressed as number of cells per milliliter (cells/mL) of sample. Zooplankton is the animal part of the plankton. Zooplankton are capable of extensive movements within the water column and are often large enough to be seen with the unaided eye. Zooplankton are secondary consumers feeding upon bacteria, phytoplankton, and detritus. Because they are the grazers in the aquatic environment, the zooplankton are a vital part of the aquatic food web. The zooplankton community is dominated by small crustaceans and rotifers. 36 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Primary productivity is a measure of the rate at which new organic matter is formed and accumulated through photosynthetic and chemosynthetic activity of producer organisms (chiefly, green plants). The rate of primary production is estimated by measuring the amount of oxygen released (oxygen method) or the amount of carbon assimilated by the plants (carbon method). Milligrams of carbon per area or volume per unit time f mg C/fm^.time)! for periphyton and macrophytes and [mg C/(m3.time)1 for phvtoplankton are units for expressing primary productivity. They define the amount of carbon dioxide consumed as measured by radioactive carbon (carbon 14). The carbon 14 method is of greater sensitivity than the oxygen light and dark bottle method, and is preferred for use in unenriched waters. Unit time may be either hour or day, depending on the incubation period. Milligrams of oxygen per area or volume per unit time fmgO / (rrAtime)] for periphyton and macrophytes and FmgO /(m3.time)1 for phvtoplankton are the units for expressing primary productivity. They define production and respiration rates as estimated from changes in the measured dissolved-oxygen concentration. The oxygen light and dark bottle method is preferred if the rate of primary production is sufficient for accurate measurements to be made within 24 hours. Unit time may be either the hour or day, depending on the incubation period. Polychlorinated biphenyls (PCBs) are industrial chemicals that are mixtures of chlorinated biphenyl compounds having various percentages of chlorine. They are similar in structure to organochlorine insecticides. Radiochemical program is a network of regularly sampled water-quality stations where samples are collected to be analyzed for radioisotypes. The streams that are sampled represent major drainage basins in the conterminous United States. Recoverable from bottom material is the amount of a given constituent that is in solution after a representative sample of bottom material has been digested by a method (usually using an acid or mixture of acids) that results in dissolution of readily soluble substances. Complete dissolution of all bottom material is not achieved by the digestion treatment and thus the determination represents less than the total amount (that is, less than 95 percent) of the constituent in the sample. To achieve comparability of analytical data, equivalent digestion procedures would be required of all laboratories performing such analyses because different digestion procedures are likely to produce different analytical results. Return period is the average time interval between occurrences of a hydrological event of a given or greater magnitude, usually expressed in years. May also be called recurrence interval. Runoff in inches (IN, in) shows the depth to which the drainage area would be covered if all the runoff for a given time period were uniformly distributed on it. Sediment is solid material that originates mostly from disintegrated rocks and is transported by, suspended in, or deposited from water; it includes chemical and biochemical precipitates and decomposed organic material, such as humus. The quantity, characteristics, and cause of the occurrence of sediment in streams are influenced by environmental factors. Some major factors are degree of slope, length of slope, soil characteristics, land usage, and quantity and intensity of precipitation. Bed load is the sediment that is transported in a stream by rolling, sliding, or skipping along the bed and very close to it. In this report, bed load is considered to consist of particles in transit within 0.25 ft of the streambed. Bed load discharge (tons per day) is the quantity of bed load measured by dry weight that moves past a section as bed load in a given time. Suspended sediment is the sediment that at any given time is maintained in suspension by the upward components of turbulent currents or that exists in suspension as a colloid. 37 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Suspended-sediment concentration is the velocity-weighted concentration of suspended sediment in the sampled zone (from the water surface to a point approximately 0.3 ft above the bed) expressed as milligrams of dry sediment per liter of water-sediment mixture (mg/L). Mean concentration is the time-weighted concentration of suspended sediment passing a stream section during a 24-hour day. Suspended-sediment discharge (tons/day) is the rate at which dry mass of sediment passes a section of a stream or is the quantity of sediment, as measured by dry mass or volume, that passes a section in a given time. It is calculated in units of tons per day as follows: concentrations (mg/L) x discharge (ftVs) x 0.0027. Suspended-sediment load is a general term that refers to material in suspension. It is not synonymous with either discharge or concentration. Total sediment discharge (tons/day) is the sum of the suspended-sediment discharge and the bed-load discharge. It is the total quantity of sediment, as measured by dry mass or volume, that passes a section during a given time. Total-sediment load or total load is a term which refers to the total sediment (bed load plus suspended-sediment load) that is in transport. It is not synonymous with total-sediment discharge. 7-day 10-year low flow (7Q10) is the discharge at the 10-year recurrence interval taken from a frequency curve of annual values of the lowest mean discharge for 7 consecutive days (the 7-day low flow). Sodium-adsorption-ratio (SAR) is the expression of relative activity of sodium ions in exchange reactions within soil and is an index of sodium or alkali hazard to the soil. Waters range in respect to sodium hazard from those which can be used for irrigation on almost all soils to those which are generally unsatisfactory for irrigation. Solute is any substance that is dissolved in water. Specific conductance is a measure of the ability of a water to conduct an electric current. It is expressed in microsiemens per centimeter at 25°C. Specific conductance is related to the type and concentration of ions in solution and can be used for approximating the dissolved-solids content of the water. Commonly, the concentration of dissolved solids (in milligrams per liter) is about 65 percent of the specific conductance (in micromhos). This relation is not constant from stream to stream, and it may vary in the same source with changes in the composition of the water. Stage-discharge relation is the relation between gage height (stage) and volume of water per unit of time, flowing in a channel. Streamflow is the discharge that occurs in a natural channel. Although the term "discharge" can be applied to the flow of a canal, the word "streamflow" uniquely describes the discharge in a surface stream course. The term "streamflow" is more general than "runoff as streamflow may be applied to discharge whether or not it is affected by diversion or regulation. Substrate is the physical surface upon which an organism lives. Natural substrate refers to any naturally occurring emersed or submersed solid surface, such as a rock or tree, upon which an organism lives. Artificial substrate is a device which is purposely placed in a stream or lake for colonization of organisms. The artificial substrate simplifies the community structure by standardizing the substrate from which each sample is taken. Examples of artificial substrates are basket samplers (made of wire cages filled with clean streamside rocks) and multiplate samplers (made of hardboard) for benthic organism collection, and plexiglass strips for periphyton. 38 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Surface area of a lake is that area outlined on the latest U.S.G.S. topographic map as the boundary of the lake and measured by a planimeter in acres. In localities not covered by topographic maps, the areas are computed from the best maps available at the time planimetered. All areas shown are those for the stage when the planimetered map was made. Surflcial bed material is that part (0.1 to 0.2 ft) of the bed material that is sampled using U.S. Series Bed-Material Samplers. Suspended (as used in tables of chemical analyses) refers to the amount (concentration) of the total concentration in a water-sediment mixture. It is associated with the material retained on a 0.45-micrometer filter. Suspended, recoverable is the amount of a given constituent that is in solution after the part of a representative water-suspended sediment sample that is retained on a 0.45 um membrane filter has been digested by a method (usually using a dilute acid solution) that results in dissolution of only readily soluble substances. Complete dissolution of all the paniculate matter is not achieved by the digestion treatment and thus the determination represents something less than the "total" amount (that is, less than 95 percent) of the constituent present in the sample. To achieve comparability of analytical data, equivalent digestion procedures are required of all laboratories performing such analyses because different digestion procedures are likely to produce different analytical results. Determinations of "suspended, recoverable" constituents are made either by analyzing portions of the material collected on the filter or, more commonly, by difference, based on determinations of (1) dissolved and (2) total recoverable concentrations of the constituent. Suspended, total is the total amount of a given constituent in the pan of representative water-suspended sediment sample that is retained on a 0.45 um membrane filter. This term is used only when the analytical procedure assures measurement of at least 95 percent of the constituent determined. A knowledge of the expected form of the constituent in the sample, as well as the analytical methodology used, is required to determine when the results should be reported as "suspended, total." Determinations of "suspended, total" constituents are made either by analyzing portions of the material collected on the filter or, more commonly, by difference, based on determinations of (1) dissolved and (2) total concentrations of the constituent. Taxonomy is the division of biology concerned with the classification and naming of organisms. The classification of organisms is based upon a hierarchial scheme beginning with Kingdom and ending with Species at the base. The higher the classification level, the fewer features the organisms have in common. For example, the taxonomy of a particular mayfly, Hexagenia limbata, is the following: Kingdom.....................Animal Phylum........................Arthopoda Class...........................Insecta Order...........................Ephemeroptera Family.........................Ephemeridae Genus..........................Hexagenia Species........................Hexagenia limbata Thermograph is an instrument that continuously records variations of temperature on a chart. The more general term "temperature recorder" is used in the table heading and refers to any instrument that records temperature whether on a chart, a tape, or any other medium. Time-weighted average is computed by multiplying the number of days in the sampling period by the concentrations of individual constituents for the corresponding period and dividing the sum of the products by the total number of days. A time- weighted average represents the composition of water that would be contained in a vessel or reservoir that had received equal quantities of water from the stream each day for the year. Tons per acre-foot indicates the dry mass of dissolved solids in 1 acre-foot of water. It is computed by multiplying the concentration of the constituent, in milligrams per liter by 0.00136. 39 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Tons per day (T/DAY) is the quantity of a substance in solution or suspension that passes a stream section during a 24- hour period. Total is the total amount of a given constituent in a representative water-suspended sediment sample, regardless of the constituent's physical or chemical form. This term is used only when the analytical procedure assures measurement of at least 95 percent of the constituent present in both the dissolved and suspended phases of the sample. A knowledge of the expected form of the constituent in the sample, as well as the analytical methodology used, is required to judge when the results should be reported as "total." (Note that the word "total" does double duty here, indicating both that the sample consists of a water- suspended sediment mixture and that the analytical method determined all of the constituent in the sample.) Total discharge is the total quantity of any individual constituent, as measured by dry mass or volume, that passes through a stream cross-section per unit of time. This term needs to be qualified, such as "total sediment discharge," "total chloride discharge," and so on. Total, recoverable is the amount of a given constituent that is in solution after a representative water-suspended sediment sample has been digested by a method (usually using a dilute acid solution) that results in dissolution of only readily soluble substances. Complete dissolution of all paniculate matter is not achieved by the digestion treatment, and thus the determination represents something less than the "total" amount (that is, less than 95 percent) of the constituent present in the dissolved and suspended phases of the sample. To achieve comparability of analytical data, equivalent digestion procedures are required of all laboratories performing such analyses, because different digestion procedures are likely to produce different analytical results. Tritium Network is a network of stations which has been established to provide baseline information on the occurrence of tritium in the Nation's surface waters. In addition to the surface-water stations in the network, tritium data are also obtained at a number of precipitations stations. The purpose of the precipitation stations is to provide an estimate sufficient for hydrologic studies of the tritium input to the United States. Water year in Geological Survey reports dealing with surface water supply is the 12-month period, October 1 through September 30. The water year is designated by the calendar year in which it ends and which includes 9 of the 12 months. Thus, the year ending September 30,1980, is called the "1980 water year." WDR is used as an abbreviation for "Water-Data Report" in the REVISED RECORDS paragraph to refer to State annual hydrologic-data reports (WRD was used as an abbreviation for "Water-Resources Data" in reports published prior to 1976). Weighted average is used in this report to indicate discharge-weighted average. It is computed by multiplying the discharge for a sampling period by the concentrations of individual constituents for the corresponding period and dividing the sum of the products by the sum of the discharges. A discharge- weighted average approximates the composition of water that would be found in a reservoir containing all the water passing a given location during the water year after thorough mixing in the reservoir. WSP is used as an abbreviation for "Water-Supply Paper" in references to previously published reports. 40 PUBLICATIONS ON TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS The U.S. Geological Survey publishes a series of manuals describing procedures for planning and conducting specialized work in water-resources investigations. The material is grouped under major subject headings called books and is further divided into sections and chapters. For example, Section A of Book 3 (Applications of Hydraulics) pertains to surface water. The chapter, the unit of publication, is limited to a narrow field of subject matter. This format permits flexibility in revision and publication as the need arises. The reports listed below are for sale by the U.S. Geological Survey, Branch of Information Services, Box 25286, Federal Center, Denver, Colorado 80225 (authorized agent of the Superintendent of Documents, Government Printing Office). Prepayment is required. Remittance should be sent by check or money order payable to the U.S. Geological Survey. Prices are not included because they are subject to change. Current prices can be obtained by writing to the above address. When ordering or inquiring about prices for any of these publications, please give the title, book number, chapter number, and "U.S. Geological Survey Techniques of Water-Resources Investigations." 1-D1. Water temperature—influential factors, field measurement, and data presentation, by H. H. Stevens, Jr., J. F. Ficke, and G. F. Smoot: USGS-TWRI Book 1, Chapter Dl. 1975. 65 pages. 1-D2. Guidelines for collection and field analysis of ground-water samples for selected unstable constituents, by W. W Wood: USGS-TWRI Book 1, Chapter D2. 1976. 24 pages. 2-D1. Application of surface geophysics to ground-water investigations, by A. A. R. Zohdy, G. P. Eaton, and D. R. Mabey: USGS-TWRI Book 2, Chapter Dl. 1974. 116 pages. 2-D2. Application of seismic-refraction techniques to hydrologic studies, by F. P. Haeni: USGS--TWRI Book 2, Chapter D2. 1988. 86 pages. 2-E1. Application of borehole geophysics to water-resources investigations, by W. S. Keys and L.M. MacCary: USGS—TWRI Book 2, Chapter El. 1971. 126 pages. 2-E2. Borehole geophysics applied to ground-water investigations, by W. S. Keys: USGS-TWRI Book 2, Chapter E2. 1990. 150 pages. 2-F1. Application of drilling, coring, and sampling techniques to test holes and wells, by Eugene Shuter and W. E. Teasdale: USGS-TWRI Book 2, Chapter Fl. 1989. 97 pages. 3-A1. General field and office procedures for indirect discharge measurements, by M. A. Benson and Tate Dalrymple: USGS-TWRI Book 3, Chapter Al. 1967. 30 pages. 3-A2. Measurement of peak discharge by the slope-area method, by Tate Dalrymple and M. A. Benson: USGS--TWRI Book 3, Chapter A2. 1967. 12 pages. 3-A3. Measurement of peak discharge at culverts by indirect methods, by G. L. Bodhaine: USGS--TWRI Book 3, Chapter A3. 1968. 60 pages. 3-A4. Measurement of peak discharge at width contractions by indirect methods, by H. F. Matthai: USGS-TWRI Book 3, Chapter A4.1967. 44 pages. 3-A5. Measurement of peak discharge at dams by indirect methods, by Harry Hulsing: USGS--TWRI Book 3. Chapter A5. 1967. 29 pages. 3-A6. General procedure for gaging streams, by R. W. Carter and Jacob Davidian: USGS-TWRI Book 3, Chapter A6. 1968. 13 pages. 3-A7. Stage measurement at gaging stations, by T. J. Buchanan and W. P. Somers: USGS-TWRI Book 3, Chapter A7. 1968. 28 pages. 3-A8. Discharge measurements at gaging stations, by T. J. Buchanan and W. P. Somers: USGS-TWRI Book 3, Chapter A8. 1969. 65 pages. 3-A9. Measurement of time of travel in streams by dye tracing, by F. A. Kilpatrick and J. F. Wilson, Jr.: USGS--TWRI Book 3, Chapter A9.1989. 27 pages. 3-A10. Discharge ratings at gaging stations, by E. J. Kennedy: USGS-TWRI Book 3, Chapter A10. 1984. 59 pages. 41 PUBLICATIONS ON TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS-Continued 3-A11. Measurement of discharge by the moving-boat method, by G. F. Smoot and C. E. Novak: USGS--TWRI Book 3, Chapter All. 1969. 22 pages. 3-A12. Fluorometric procedures for dye tracing, Revised, by J. F. Wilson, Jr., E. D. Cobb, and F. A. Kilpatrick: USGS- -TWRI Book 3, Chapter A12.1986. 34 pages. 3-A13. Computation of continuous records of streamflow, by E. J. Kennedy: USGS--TWRI Book 3, Chapter A13. 1983. 53 pages. 3-A14. Use of flumes in measuring discharge, by F. A. Kilpatrick and V. R. Schneider: USGS--TWRI Book 3, Chapter A14. 1983.46 pages. 3-A15. Computation of water-surface profiles in open channels, by Jacob Davidian: USGS--TWRI Book 3, Chapter A15.1984. 48 pages. 3-A16. Measurement of discharge using tracers, by F. A. Kilpatrick and E. D. Cobb: USGS--TWRI Book 3, Chapter A16. 1985. 52 pages. 3-A17. Acoustic velocity meter systems, by Antonius Laenen: USGS--TWRI Book 3, Chapter A17.1985. 38 pages. 3-A18. Determination of stream reaeration coefficients by use of tracers, by F. A. Kilpatrick, R. E. Rathbun, Nobuhiro Yotsukura, G. W. Parker, and L. L. DeLong: USGS--TWRI Book 3, Chapter A18. 1989. 52 pages. 3-A19. Levels at streamflow gaging stations, by E.J. Kennedy: USGS-TWRI Book 3, Chapter A19. 1990. 31 pages. 3-A20. Simulation ofsoluable waste transport and buildup in surface waters using tracers, by F. A. Kilpatrick: USGS--TWRI Book 3, Chapter A20.1993. 38 pages. 3-A21 Stream-gaging cableways, by C. Russell Wagner: USGS--TWRI Book 3, Chapter A21. 1995. 56 pages. 3-B1. Aquifer-test design, observation, and data analysis, by R. W Stallman: USGS--TWRI Book 3, Chapter Bl. 1971. 26 pages. 3-B2. Introduction to ground-water hydraulics, a programed text for self-instruction, by G. D. Bennett: USGS-- TWRI Book 3, Chapter B2.1976. 172 pages. 3-B3. Type curves for selected problems of flow to wells in confined aquifers, by J. E. Reed: USGS--TWRI Book 3, Chapter B3. 1980. 106 pages. 3-B4. Regression modeling of ground-water flow, by R. L. Cooley and R. L. Naff: USGS--TWRI Book 3, Chapter B4. 1990. 232 pages. 3-B4. Supplement L Regression modeling of ground-water flow - Modifications to the computer code for nonlinear regression solution of steady-state ground-water flow problems, by R. L. Cooley: USGS--TWRI Book 3, Chapter B4. 1993. 8 pages. 3-B5. Definition of boundary and initial conditions in the analysis of saturated ground-water flow systems--An introduction, by O. L. Franke, T. E. Reilly, and G. D. Bennett: USGS--TWRI Book 3, Chapter B5. 1987. 15 pages. 3-B6. The principle of superposition and its application in ground-water hydraulics, by T. E. Reilly, O. L. Franke, and G. D. Bennett: USGS-TWRI Book 3, Chapter B6. 1987. 28 pages. 3-B7. Analytical solutions for one-, two-, and three-dimensional solute transport in ground-water systems with uniform flow, by E. J. Wexler: USGS--TWRI Book 3, Chapter B7. 1992. 190 pages. 3-C1. Fluvial sediment concepts, by H. P. Guy: USGS--TWRI Book 3, Chapter C1. 1970. 55 pages. 3-C2. Field methods for measurement of fluvial sediment, by H. P. Guy and V. W. Norman: USGS--TWRI Book 3, Chapter C2. 1970. 59 pages. 3-C3. Computation of fluvial-sediment discharge, by George Porterfield: USGS--TWRI Book 3, Chapter C3. 1972. 66 pages. 4-A1. Some statistical tools in hydrology, by H. C. Riggs: USGS--TWRI Book 4, Chapter A1. 1968. 39 pages. 4-A2. Frequency curves, by H. C. Riggs: USGS--TWRI Book 4, Chapter A2. 1968. 15 pages. 4-B1. Low-flow investigations, by H. C. Riggs: USGS--TWRI Book 4, Chapter B1. 1972. 18 pages. 42 PUBLICATIONS ON TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS-Continued 4-B2. Storage analyses for water supply, by H. C. Riggs and C. H. Hardison: USGS--TWRI Book 4, Chapter B2. 1973. 20 pages. 4-B3. Regional analyses ofstreamflow characteristics, by H. C. Riggs: USGS--TWRI Book 4, Chapter B3.1973. 15 pages. 4-D1. Computation of rate and volume of stream depletion by wells, by C. T. Jenkins: USGS--TWRI Book 4, Chapter Dl. 1970.17 pages. 5-A1. Methods for determination of inorganic substances in water and fluvial sediments, by M.J. Fishman and L. C. Friedman, editors: USGS--TWRI Book 5, Chapter Al. 1989. 545 pages. 5-A2. Determination of minor elements in water by emission spectroscopy, by P. R. Barnett and E. C. Mallory, Jr.: USGS-- TWRI Book 5, Chapter A2.1971. 31 pages. 5-A3. Methods for the determination of organic substances in water and fluvial sediments, edited by R. L. Wershaw, M. J. Fishman, R. R. Grabbe, and L. E. Lowe: USGS--TWRI Book 5, Chapter A3. 1987. 80 pages. 5-A4. Methods for collection and analysis of aquatic biological and microbiological samples, by L. J. Britton and P. E. Greeson, editors: USGS--TWRI Book 5, Chapter A4. 1989. 363 pages. 5-A5. Methods for determination of radioactive substances in water and fluvial sediments, by L.L. Thatcher, V. J. Janzer, and K. W. Edwards: USGS--TWRI Book 5, Chapter A5. 1977.95 pages. 5-A6. Quality assurance practices for the chemical and biological analyses of water and fluvial sediments, by L. C. Friedman and D. E. Erdmann: USGS--TWRI Book 5, Chapter A6.1982. 181 pages. 5-C1. Laboratory theory and methods for sediment analysis, by H. P. Guy: USGS-TWRI Book 5, Chapter Cl. 1969. 58 pages. 6-A1. A modular three-dimensional finite-difference ground-water flow model, by M. G. McDonald and A. W. Harbaugh: USGS--TWRI Book 6, Chapter Al. 1988. 586 pages. 6-A2. Documentation of a computer program to simulate aquifer-system compaction using the modular finite-difference ground-water flow model, by S. A. Leake and D. E. Prudic: USGS--TWRI Book 6, Chapter A2. 1991.68 pages. 6-A3. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 1: Model Description and User's Manual, by L. J. Torak: USGS--TWRI Book 6, Chapter A3.1993. 136 pages 6-A4. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 2: Derivation of finite-element equations and comparisons with analytical solutions, by R. L. Cooley: USGS--TWRI Book 6, Chapter A4. 1992. 108 pages. 6-A5. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 3: Design philosophy and programming details, by L. J. Torak: USGS-TWRI Book 6, Chapter A5,1993. 243 pages. 6-A6. A coupled surface-water and ground-water flow model (MODBRANCH) for simulation of stream-aquifer interaction, by Eric D. Swain and Eliezer J. Wexler. 1995. 125 pages. 7-C1. Finite difference model for aquifer simulation in two dimensions with results of numerical experiments, by P. C. Trescott, G. F. Pinder, and S. P. Larson: USGS--TWRI Book 7, Chapter Cl. 1976. 116 pages. 7-C2. Computer model of two-dimensional solute transport and dispersion in ground water, by L. F. Konikow and J. D. Bredehoeft: USGS--TWRI Book 7, Chapter C2. 1978. 90 pages. 7-C3. A model for simulation of flow in singular and interconnected channels, by R. W. Schaffranek, R. A. Baltzer, and D. E. Goldberg: USGS--TWRI Book 7, Chapter C3. 1981. 110 pages. 8-A1. Methods of measuring water levels in deep wells, by M. S. Garber and F. C. Koopman: USGS--TWRI Book 8, Chapter Al. 1968. 23 pages. 8-A2. Installation and service manual for U.S. Geological Survey manometers, by J. D. Craig: USGS--TWRI Book 8, Chapter A2.1983. 57 pages. 8-B2. Calibration and maintenance of vertical-axis type current meters, by G. F. Smoot and C. E. Novak: USGS--TWRI Book 8, Chapter B2.1968. 15 pages. 44 THIS PAGE WAS LEFT BLANK INTENTIONALLY 45 ATLANTIC OCEAN igntou* ond --•» &«dim*ntary rock* v V k 0105 010720 10108 *165 EXPLANATION SURFACE-WATER STATION AND NUMBER QUALITY-OF-WATER STATION AND NUMBER QUALITY-OF-WATER PARTIAL RECORD STATION AND NUMBER LAKE-ELEVATION STATION AND NUMBER WELL AND WELL NUMBER -Mop or«o 01 23456 KILOMETERS |_LTJ__ir_L+_h 01234 MILES Figure 12.--Rfo Guajataca basin. 46 RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR LOCATION.—Lat 18°18'01", long 66 0 52'24", Hydrologic Unit 21010001 at bridge on Highway 111, 0.1 mi (0.2 km) upstream from Quebrada Anon, and 0.4 mi (0.6 km) east of Lares. DRAINAGE AREA.—3.16 mi 2 (8.18 km*) . WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February 1959 to February 1962 (annual low-flow measurements only), January 1963 to April 1969 (monthly measurements only). Hay 1969 to December 1970 (February to Hay 1971 and Harch 1974 to November 1989, monthly measurements only), December 1989 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 935 ft (285 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. Small diversion above station for sewage treatment plant; effluent re-enters stream below station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC APR AUG 1 13 12 2 10 9.7 3 31 8.9 4 26 8.1 5 15 7.7 6 12 7.5 7 11 7.4 8 18 6.7 9 10 6.1 10 9.0 31 11 7.9 13 12 8.9 13 13 22 10 14 16 8.6 15 8.5 11 16 7.2 15 17 35 12 18 22 24 19 11 12 20 8.8 13 21 22 11 22 10 13 23 8.6 12 24 7.7 10 25 7.2 9.0 26 21 8.0 27 10 7.7 28 26 7.1 29 23 6.5 30 19 9.2 31 26 TOTAL 482.8 330.2 MEAN 15.6 11.0 MAX 35 31 HIN 7.2 6.1 AC-FT 958 655 CFSM 4.93 3.48 IN. 5.68 3.89 6.8 6.3 5.9 6.1 5.4 5.5 5.1 5.1 5.8 8.1 18 5.5 5.0 4.9 4.4 4.2 4.3 4.3 3.8 4.0 4.3 4.5 3.5 4.0 4.0 3.3 3.2 3.2 3.9 3.1 2.9 158.4 5.11 18 2.9 314 1.62 1.86 STATISTICS OF MONTHLY MEAN DATA MEAN 16.9 8.65 MAX 33.7 16.7 (WY) 1991 1971 HIN 8.52 3.75 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 3.84 7.31 1971 1.35 1991 2.9 13 24 5.6 3.5 2.6 2.5 7.0 3.7 2.0 1.9 3.4 15 11 3.8 2.4 2.2 1.8 5.4 11 56 39 9.6 15 6.4 .9 .3 .3 .2 .0 3.8 276.2 8.91 56 1.8 548 2.82 3.25 4.0 3.6 3.4 3.2 3.2 3.2 3.4 3.2 9.4 4.7 4.0 3.0 2.3 2.3 2.1 2.0 1.9 1.8 1.9 1.7 2.2 1.7 1.6 1.4 1.3 1.1 1.2 1.2 —— 76.0 2.71 9.4 1.1 151 .86 .89 FOR WATER YEARS 1969 3.41 8.91 1997 .66 1991 2.71 7.21 1996 .93 1992 1.2 1.1 1.1 1.3 1.1 .93 1.1 1.2 .87 .90 .73 .65 .65 .65 .79 .70 1.3 2.5 8.5 3.2 2.4 2.1 1.7 1.8 1.6 1.8 1.5 11 4.9 3.3 1.9 64.47 2.08 11 .65 128 .66 .76 - 1997 2.23 6.38 1971 .92 1994 FOR 1996 CALENDAR YEAR 3154.8 8.62 129 1.2 1.4 6260 2.73 37.14 20 4.9 1.9 Sep 10 Jan 13 Jan 7 1.9 1.8 1.8 1.8 1.8 1.7 1.9 1.7 1.6 1.6 1.5 1.8 1.8 1.8 1.8 1.7 1.2 1.2 1.0 .90 1.8 5.1 1.4 .89 .75 .70 .85 .78 .68 .71 —— 45.96 1.53 5.1 .68 91 .48 .54 , BY WATER 3.38 7.63 1993 1.09 1994 FOR 1997 2024 5 88 2110 15 4020 1 23 13 2 .77 .70 .67 1.1 .75 .75 .65 .64 .68 .68 .64 .64 .60 .57 .59 .56 .50 .51 .58 .98 62.2 66.0 e!2 613 el. 8 elO e2.8 e3.5 63.2 e3.0 62.5 73.56 2.37 13 .50 146 .75 .87 YEAR (WY) 9.23 20.2 1995 2.37 1997 62.0 el. 5 el. 2 el. 6 62.1 el. 9 62.0 el. 9 el. 8 el. 6 62.1 el. 9 el. 7 el. 8 el. 6 el. 7 el. 6 el. 3 el. 4 62.8 el. 2 6.90 6.96 6.96 el. 8 62.5 el. 5 6.96 el. 4 63.4 —— 51.08 1.70 3.4 .90 101 .54 .60 7.24 16.4 1995 1.70 1997 WATER YEAR .97 .55 .50 .56 .71 .76 .84 .6 .95 Sep 24 May 17 Hay 13 Sep 24 Sep 24 62.5 el. 7 el. 2 el. 3 62.0 el.O el.O 1.7 1.6 1.3 1.2 1.6 1.4 3.0 5.0 2.2 1.3 1.7 1.5 1.3 1.4 1.4 1.3 1.4 1.4 2.3 1.8 1.4 2.2 1.6 1.9 53.6 1.73 5.0 1.0 106 .55 .63 4.12 9.85 1969 1.73 1997 1.4 1.6 5.9 2.5 1.8 1.7 1.9 5.7 11 8.9 2.5 2.5 2.7 15 3.7 4.0 2.2 2.3 2.4 30 13 4.1 16 8.8 4.0 2.6 2.5 14 5.6 4.6 6.2 191.1 6.16 30 1.4 379 1.95 2.25 6.11 11.1 1996 3.34 1970 WATER YEARS 1969 6.41 9.08 4.13 216 .47 .51 5300 21.30 4640 2.03 27.55 15 3.5 .96 Oct Jan Jan Oct Oct 16 8.8 2.7 3.1 2.5 2.9 2.2 2.0 1.7 1.5 1.4 5.8 3.4 6.9 2.6 2.6 1.1 1.3 1.6 2.2 3.3 7.3 3.8 88 11 4.2 14 5.8 7.2 4.7 —— 221.6 7.39 88 1.1 440 2.34 2.61 11.9 24.7 1996 5.95 1993 - 1997 1996 1994 7 1990 13 1991 9 1991 7 1990 7 1990 e Estimated RIO QUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR MATER-QUALITY RECORDS LOCATION.—Lat 18°18'01", long 66°52'24>, at bridge on Highway 111 (km 32.9), 0.1 ml (0.2 km) upstream from Quebrada Anon, and 0.4 mi (0.6 km) northeast of Lares plaza. DRAINAGE AREA.—3.16 mi* (8.18 km1 ). PERIOD OF RECORD.—Water years 1958-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 47 DATE TIME OXYGEN, OXYGEN DIS- DEMAND, SOLVED CHEM- TUR- OXYGEN, (PER- ICAL BID- DIS- CENT (HIGH ITY SOLVED SATUR- LEVEL) (NTU) (MG/L) ATION) (MG/L) (00076) (00300) (00301) (00340) OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... 1110 1300 0920 1130 11 4.2 2.3 3.9 226 246 231 302 6.7 6.4 7.6 7.8 22.5 21.5 23.5 24.0 7.1 13 8.4 7.3 7.8 8.7 6.6 6.7 89 99 80 82 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K1800 K1300 3500 3200 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 2900 4500 5900 8500 DATE OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... DATE OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... DATE OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 85 — 89 68 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — 0.11 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.24 0.22 <0.20 0.26 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 25 — 24 22 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 31 — 30 16 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.5 2.2 0.99 1.5 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.4 — 6.7 3.1 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 146 — 145 132 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 11 9.7 4.4 6.7 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 10 — 11 6.2 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.44 — 0.91 1.39 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.030 0.080 0.060 0.030 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 0.5 0.3 RESIDUE TOTAL AT 105 DBG. C, SUS- PENDED (MG/L) (00530) <1 18 9 6 ARSENIC TOTAL (UG/L AS AS) (01002) 1 — 1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 — 2.2 2.8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 2.30 2.00 0.790 1.20 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 90 94 81 120 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 <0.010 0.015 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 20 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 2.30 2.00 0.800 1.30 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 6.8 — 9.5 8.0 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.020 0.030 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 — 12 8.4 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.22 0.20 <0.20 0.22 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K - non- ideal count 48 RIO GUAJATACA BASIN 50010500 RIO OUAJATACA AT LARES, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 31... FEB 1997 11... JUN 12... AUO 22... IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UO/L (UO/L 320 290 MANGA- NESE, MERCURY TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UO/L (UO/L METHY- SELE- NIUM, TOTAL (UO/L SILVER, TOTAL RECOV- ERABLE (UO/L ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL (UO/L (MO/L BLUE ACTIVE PHENOLS SUB- TOTAL STANCE AS FE) AS PB) AS MN) AS HO) AS SB) AS AO) AS ZN) AS CN) (UO/L) (MO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) 30 <0.10 54 <0.10 <10 <0.010 <1 <0.01 <10 <0.010 <0.01 RIO GUAJATACA BASIN 50010800 LAGO GUAJATACA AT DAMSITE NEAR QUEBRADILLAS, PR 49 LOCATION.—Lat 18°24'02", long 66°55'25", Hydrologic Unit 21010002, on right bank, in a concrete intake tower at Damsite, 5.2 mi (8.4 km) southeast from Quebradillas plaza, 0.5 mi (0.8 km) northeast from Iglesia San Antonio da Padua and 2.8 mi (4.5 km) from Escuela Segunda Unidad Baldorioty de Castro. DRAINAGE AREA.—24.6 mi* (63.71 km*) ELEVATION RECORDS PERIOD OF RECORD.—April 1995 to current year. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Guajataca was completed in 1928. The dam is a semihydraulic earthfill structure about 123 ft (37 m) bight, a top width of 31 ft (9.5 m) at crest elevation of 664 ft (202.5 m), a base width of 623 ft (190 m), a crest lenght of 1,036 ft (316 m) and has a maximum storage capacity of 49,200 acre-feet (60.6 hm3 ). The Guajataca Dam is owned by the Puerto Rico Electric Power Authority (P.R.E.P.A) and provides water for the municipalities of Aguadilla, Isabela, Moca, Aguada and Quebradillas although its primary purpose is for agricultural irrigation for the flatlands of the area. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 645.48 ft (196.7 m), Oct. 18, 1995; minimum elevation, 611.22 ft (186.3 m) Aug. 16, 1997. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 644.46 ft (196.4 m), Jan. 23; minimum elevation, 611.22 ft (186.3 m), Aug. 16. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 593 600 Contents, in acre-feet 0 2,405 Elevation, in feet 625 650 Contents, in acre-feet 15,295 36,403 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES DAY 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN OCT NOV DEC JAN APR JUL AUG 640.27 A 640.36 640.44 640.46 640.43 640.39 640.36 640.30 640.22 640.13 640.05 640.21 640.31 640.29 641.32 641.27 641.22 641.14 641.05 640.96 640.87 640.78 640.68 640.75 640.69 640.77 640.74 640.68 640.75 641.99 641.92 641.98 641.94 641.84 641.75 641.66 641.56 641.44 641.38 641.65 641.60 641.50 641.43 641.38 639.40 639.38 639.70 639.77 639.68 639.57 639.45 639.33 639.22 639.10 638.99 639.00 639.03 639.24 639.24 638.59 638.08 637.86 637.77 637.65 637.55 637.44 637.32 637.24 637.12 637.05 636.92 636.79 636.65 636.51 634.64 634.51 634.38 634.24 634.11 633.97 633.84 633.69 633.56 633.41 633.26 633.10 632.94 632.79 632.64 630.34 630.19 630.00 629.82 629.64 629.53 629.39 629.20 629.02 628.82 628.63 628.42 628.22 628.03 627.83 624.42 624.19 623.98 623.76 623.54 623.39 623.35 623.22 623.12 622.95 623.24 623.17 622.98 622.77 622.56 623.54 623.53 623.46 623.29 623.11 622.93 622.69 622.52 622.37 622.17 621.98 621.79 621.61 621.41 621.21 618.46 618.43 618.19 617.92 617.68 617.39 617.10 616.84 616.54 616.26 615.98 615.69 615.48 615.56 615.97 A A A A A A A A A A A A A 611.44 611.33 617.38 617.43 617.39 617.32 617.21 617.09 616.95 616.85 616.69 616.49 616.27 616.05 615.86 615.64 615.51 640.23 640.59 640.75 640.73 640.69 640.69 640.64 640.67 640.60 640.52 641.06 641.31 641.52 641.60 641.67 641.94 642.85 642.75 642.36 642.23 641.29 641.18 641.06 640.94 640.83 640.73 640.64 640.52 640.41 640.29 639.15 639.04 638.93 638.85 639.19 641.39 644.42 644.28 643.88 643.26 636.37 636.23 636.09 635.96 635.83 635.71 635.57 635.43 635.31 635.19 632.49 632.36 632.23 632.18 632.11 631.97 631.81 631.65 631.49 631.32 627.63 627.42 627.22 627.02 626.81 626.60 626.42 626.23 626.01 625.80 622.34 622.12 621.89 621.66 621.42 621.24 621.12 621.10 621.90 622.54 620.99 620.76 620.52 620.30 620.09 619.87 619.62 619.38 619.36 619.38 640.56 640.64 640.77 641.08 641.25 641.32 642.22 642.18 642.14 642.08 642.05 640.17 640.05 639.93 639.80 639.67 639.55 642.50 641.69 640.85 640.07 639.41 639.03 635.05 634.93 634.78 ___ ___ ___ 631.16 630.99 630.90 630.79 630.64 630.48 625.55 625.33 625.09 624.86 624.64 ___ 622.80 623.53 623.89 623.83 623.71 623.57 619.19 618.97 618.71 618.45 618.24 ___ 641.32 640.05 642.85 640.68 641.99 639.55 644.42 638.85 638.59 634.78 634.64 630.48 630.34 624.64 624.42 621.10 623.54 618.24 616.00 615.79 615.55 615.31 615.09 614.85 614.64 614.39 614.14 613.87 A A A A A A 618.46 613.87 611.54 611.81 611.71 612.57 614.10 614.78 614.91 614.98 615.21 615.19 615.06 615.38 616.64 617.01 617.00 617.21 617.21 611.33 615.33 615.09 614.94 614.76 614.57 614.46 614.30 614.17 614.73 614.84 614.69 614.62 614.51 614.32 614.16 617.43 614.16 CAL YR 1996 WTR YR 1997 MAX 642.99 MAX 644.42 MIN 629.08 MIN 611.33 A No gage-height record so RIO GUAJATACA BASIN 50011000 CANAL PRINCIPAL DE DIVERSIONES AT LAGO DE GUAJATACA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°24'02", long 66°55'27", off Highway 476 at Lago Guajataca outlet, 3.0 mi (4.8 km) southwest of Segunda Unidad Baldorioty de Castro, and 5.3 mi (8.5 km) south of Quebradillas Plaza. DRAINAGE AREA.--Indeterminate. PERIOD OF RECORD.—Water years 1958-64, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 15... FEB 1997 10... MAY 20... AUG 21... DATE NOV 1996 15... FEB 1997 10... MAY 20... AUG 21... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET D0CT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1200 E65 1145 75 1345 65 0800 60 HARD- NESS TOTAL (MG/L AS CAC03) (00900) 140 — 130 140 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.26 0.29 0.53 0.87 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 49 — 47 50 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 7.2 — 4.9 7.2 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.26 0.61 0.53 0.89 296 306 293 308 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 3.6 — 4.1 4.2 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 144 — 164 174 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 1.1 2.7 2.4 4.0 7.0 7.2 7.8 7.6 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 7.0 — 6.1 5.7 24.0 0 24.0 0 27.0 1 27.5 1 SODIUM AD- SORP- TION RATIO (00931) 0.3 — 0.2 0.2 RESIDUE SOLIDS, TOTAL DIS- AT 105 SOLVED DEG. C, (TONS SUS- PER FENDED DAY) (MG/L) (70302) (00530) E25.2 — 28.7 28.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 0.030 <0.020 <0.020 3 1 1 5 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ .90 .40 .0 .4 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.6 — 2.1 1.9 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) — 0.320 <0.010 0.020 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — 1.0 3.2 2.9 3.6 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 100 140 130 140 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — <10 — 12 38 37 46 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — 0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) <0.020 0.320 <0.020 0.020 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — <10 16 <10 <10 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 7.6 — 13 6.3 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.060 <0.010 0.130 0.380 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — K14 4 K4 97 K4 K12 K80 K99 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 6.9 — 8.9 7.9 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.28 0.40 0.49 COPPER, TOTAL RECOV- ERABLE (UG/L AS CO) (01042) <1.0 — <io — DATE NOV 1996 15... FEB 1997 10... MAY 20... AUG 21... E - estimated K - non-ideal count RIO OUAJATACA BASIN 50011000 CANAL PRINCIPAL DE DIVERSIONES AT LAOO DE OUAJATACA, PR—Continued MATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 51 DATE NOV 1996 15... FEB 1997 10... MAY 20... AUQ 21... IRON, TOTAL RECOV- ERABLE (UO/L AS PB) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS UN) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) SELE- NIUM, TOTAL (UO/L AS SB) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) METHY- ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL PHENOLS (UO/L (MO/L TOTAL AS ZN) AS CN) (UO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 50 30 110 <0.10 80 <0.10 <10 <0.010 <10 <0.010 BLUE ACTIVE SUB- STANCE (MO/L) (38260) <0.01 <0.01 52 RIO GUAJATACA BASIN 50011400 RIO GUAJATACA ABOVE MOUTH NEAR QUEBRADILLAS, PR—Continued WATER-QUALITY RECORDS LOCATION.—Lat 18°28'31", long 66°57'46", Hydrologic Unit 21010002, on left bank at ford 1.7 mi (2.7 km) upstree from bridge on highway 2, 1.6 mi (2.6 km) west of Quebradillas plaza, 2.1 mi (3.4 km) upstream from Atlantic Ocean, and 6.6 mi (10.6 km) downstream from Lago Guajataca. DRAINAGE AREA.—Indeterminate PERIOD OF RECORD.—Water years 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MAY 22 AUO DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1996 1030 11 489 7.0 23.0 1.0 6.0 68 <10 K140 K330 1997 1205 12 495 7.8 24.0 0.30 7.6 87 <10 K60 K82 1055 16 466 8.1 25.0 0.37 6.6 79 <10 K120 K190 1245 26 408 7.9 26.0 1.4 7.7 94 <10 K160 290 ALKA- DATE NOV 1996 15... MAR 1997 06... MAY 22... AUG 21... DATE NOV 1996 15... MAR 1997 06... MAY 22... AUG 21... DATE NOV 1996 15... MAR 1997 06... MAY 22... AUG 21... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 200 — 230 ~"" FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- 0.14 ~~ NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 <0.20 <0.20 0.22 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 67 — 60 "~ SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 6.6 -- 34 ~" ~ NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.9 2.1 1.7 1.1 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.0 __ 20 — - SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 252 -- 343 ~~ NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 8.3 9.3 7.4 5.0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 16 — 35 -- SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.77 — 14.8 -- PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 0.040 <0.020 <0.020 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 1 -- RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 3 14 4 -- ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.5 — 2.7 -- NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.80 2.10 1.60 0.910 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- 70 — LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 200 200 190 170 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 20 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 __ <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.80 2.10 1.60 0.910 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 7.4 — 35 ~~ NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.020 0.030 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 27 — 43 — — NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 -- <0.20 0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- <10 -- K - non- ideal count RIO GUAJATACA BASIN 50011400 RIO GUAJATACA ABOVE MOUTH NEAR QUEBRADILLAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 15... MAR 1997 06... MAY 22... AUG 21... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 70 50 10 <0.10 <1 <10 <0.10 <1 <1 <1 <0.010 <0.010 <1 <1 <0.01 <0.01 54 THIS PAGE WAS LEFT BLANK INTENTIONALLY ATLANTIC OCEAN 55 Drainofit boundari*i indeitrminate in »im**fan* »«rran* Bayanty igneau* and »*<Jimenfory rock* -t\VJ( */ < '&& V^- _ .Jt «.'* *r»n»«^7^'- \ Oralnaf t *.«..^ V.^X \ UTUAOO EXPLANATION L oi48 SURFACE-WATER STATION AND NUMBER JL- 0123456 KILOMETERS 01234 MILES Figure 13.-Rio Camuy basin. 56 RIO CAMUY BASIN 50014800 RIO CAMOY NEAR BAYANEY, PR LOCATION.--Lat 18°23'48", long 66049'04", Bydrologic Unit 21010002, on left bank at Highway 488, 1.4 mi (2.2 km) southeast of school at Santiago, 0.9 mi (1.4 km) northwest from Escuela Manuel A. Rivera at Bayaney and 9.1 mi (14.6 km) upstream from mouth. DRAINAGE AREA.—Indeterminate. PERIOD OF RECORD.—May 1984 to current year. GAGE.—Water-stage recorder. Elevation of gage is 341 ft (104 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 151 204 2 113 140 3 167 123 4 207 115 5 190 109 6 146 104 7 117 101 8 135 98 9 115 96 10 98 156 11 94 147 12 91 147 13 115 136 14 145 101 15 109 100 16 92 230 17 153 194 18 202 176 19 128 186 20 97 139 21 348 157 22 251 210 23 204 177 24 132 169 25 115 138 26 171 117 27 237 106 28 171 100 29 208 97 30 208 116 31 311 —— TOTAL 5021 4189 MEAN 162 140 MAX 348 230 MIN 91 96 STATISTICS OF MONTHLY MEAN MEAN 201 118 MAX 427 244 (WY) 1986 1986 MIN 81.6 60.0 (WY) 1988 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 99 90 87 85 82 78 76 74 73 74 253 117 88 82 79 77 74 70 68 67 68 71 67 64 69 64 63 62 62 59 58 2500 80.6 253 58 DATA 68.8 97.4 1988 49.7 1989 57 151 389 224 101 83 76 74 88 72 e65 e?0 e!20 e!68 e82 e?5 e?3 e?0 e!20 e!80 e360 e600 e420 301 223 174 150 138 124 117 116 5061 163 600 57 FOR WATER 59.0 163 1997 33.1 1991 118 108 102 97 94 91 88 89 86 87 82 81 78 76 74 72 70 69 69 68 67 67 64 63 62 61 58 57 —— 2198 78.5 118 57 YEARS 1984 51.6 96.4 1996 29.2 1992 56 55 55 55 54 54 53 52 50 50 49 48 47 47 47 48 49 54 53 95 61 55 50 48 47 47 46 53 81 70 60 1689 54.5 95 46 - 1997 47.8 66.0 1992 23.7 1994 FOR 1996 CALENDAR YEAR 45152 123 3310 35 36 221 79 47 Sep 10 May 4 Apr 30 55 50 50 48 47 46 45 45 44 44 43 42 42 41 41 40 40 41 40 40 42 58 65 48 38 37 38 38 38 37 —— 1323 44.1 65 37 , BY WATER 90.0 202 1986 28.0 1994 37 36 38 36 36 35 35 34 41 49 38 40 36 35 35 e34 e33 e32 e32 e31 e31 e36 e65 e!20 e!30 e!25 e85 eSS e43 e60 e!18 1591 51.3 130 31 YEAR (WY) 172 624 1986 43.2 1989 e85 e47 e43 e36 e34 e34 e32 e32 e30 e29 e34 e34 e34 e32 e32 e30 e31 e36 e40 ellO eSO e40 e40 e32 e32 e73 e60 e40 e38 e60 —— 1280 42.7 110 29 109 235 1995 42.7 1997 FOR 1997 WATER YEAR 31126 85.3 600 29 32 1530 10.19 167 64 36 Jan 22 Jun 10 Jun 5 Oct 21 Oct 21 e46 e36 e36 e34 e34 e34 e34 e62 eSS e36 e34 e38 e38 e34 e!40 •60 e40 e40 e40 e38 e58 e40 e36 e36 e40 eSl e38 e36 e62 e45 e40 1391 44.9 140 34 73.9 109 1989 38.8 1994 WATER 104 179 61 3820 16 17 6450 17 15 202 67 34 e38 e34 e38 e47 e36 e34 e34 elOO ell? e!68 ellO e67 e83 e!22 e93 el!3 e75 e65 e60 e!66 356 172 175 230 100 74 62 62 69 70 60 3030 97.7 356 34 91.5 137 1996 47.9 1993 YEARS 1984 - .5 Oct 7 Mar 18 Mar 16 Oct 7 .66 Oct 7 Mar 22 73 141 83 61 54 52 50 48 46 42 41 45 59 49 55 49 44 40 38 36 35 39 43 115 128 59 84 110 66 68 —— 1853 61.8 141 35 163 363 1996 61.8 1997 1997 1986 1994 1985 1994 1994 1985 1985 1994 e Estimated 57 Igneous ontf f - sedirntmory rock* Oroinogt £»oyra»ory~x ^ 020050' !*lflnd divide- '"—•H .• Drama 91 boundary ...•*-••-«•'•• \ 'cfio'ltsX-/' \ St'o 9ga»on)Ho \ ^\*A / ft '° T*!'«tioo ^ bo*in batin .»l^W»Mhi EXPLANATION Ht» 0t,7nD6'(1 ^0284 SURFACE-WATER STATION AND NUMBER T 0205 QUALJTY-OF-WATER STATION AND NUMBER ^7f»ooso QUAUTY-OF-WATER PARTIAL RECORD V waww STAT,ON AND NUMBER ^0280 A 204 DAILY SEDIMENT STATION AND NUMBER WELL AND WELL NUMBER 1026140 LAKE-ELEVATION STATION AND NUMBER 0123456 KILOMETERS II II i i 0 1234 MiLES Figure 14.--Rio Grande de Arecibo basin. 58 RIO GRANDE DE ARECIBO BASIN 50020100 LAGO GARZAS NEAR ADJUNTAS, PR LOCATION.—Lat 18°08'20", long 66°44'29", Hydrologic Unit 21010002, in power gate tower of Garzas Dam on Rio Vacas, 1.7 mi (2.7 km) upstream from Rio Garzas, and 2.2 mi (3.5 km) southwest of Adjuntas. DRAINAGE AREA.—15.6 mi 3 (40.4 km*). ELEVATION RECORDS PERIOD OF RECORD.—January 1988 to Hay 1989, March 1993 to current year. GAGE.—Water-stage recorder. Datum of gage is 2,400.00 ft (731.520 m) above mean sea level. Prior to Hay 25, 1988 at datum 2,376.80 ft (724.449 m), Hay 25 to July 13, 1988 at datum 2,338.08 ft (712.647 m), July 14, 1988 to Hay 25, 1989 at datum 2,337.82 ft (712.560 m), above mean sea level. REMARKS.--Lake is formed by earthfill dam completed in 1943. Outflow from lake controlled by vertical-lift sluice gate and fixed-crest concrete spillway. Spillway elevation, 2,415.00 ft (736.09 m). Lake is used for irrigation and power production. Operated by P.R. Electric Power Authorithy. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.—Maximum elevation 2,417.66 ft (736.903 m), Hay 27,1993; minimum elevation, 2,364.79 ft (720.788 m), Aug. 23, 1988. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximum elevation, 2,415.28 ft (736.177 m), Oct. 29; minimum elevation, 2,376.80 ft (724.449 m), Jul. 13. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 2,364 2,382 2,394 Contents, in acre-feet 660 1,500 2,250 Elevation, in feet 2,415 2,418 Contents, in acre-feet 4,082 4,411 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES DEC JAN FEB MAR APR MAY JUN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN CAL WTR 2414.77 2414.77 2414.77 2414.77 2414.77 2414.75 2414.75 2414.74 2414.74 2414.74 2414.74 2414.74 2414.74 2414.74 2414.74 2414.74 2414.74 2414.74 2414.82 2414.79 2414.85 2414.88 2414.77 2414.75 2414.74 2414.72 2414.76 2414.76 2414.97 2414.76 2414.73 2414.97 2414.72 YR 1996 YR 1997 2414.73 2414.73 2414.73 2414.73 2414.71 2414.70 2414.70 2414.70 2414.70 2414.78 2414.69 2414.81 2414.71 2414.70 2414.70 2414.70 2414.85 2414.84 2414.76 2414.78 2414.82 2414.81 2414.81 2414.77 2414.77 2414.75 2414.75 2414.75 2414.75 2414.75 —— 2414.85 2414.69 MAX 2415. MAX 2414. 2414.75 2414.75 2414.75 2414.83 2414.84 2414.70 2414.70 2414.68 2414.68 2414.72 2414.72 2414.68 2414.74 2414.68 2414.68 2414.68 2414.66 2414.66 2414.63 2414.63 2414.63 2414.64 2414.62 2414.61 2414.61 2414.59 2414.59 2414.59 2414.59 2414.57 2414.57 2414.84 2414.57 20 MIN 97 MIN 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2414. 2410.81 2378.12 54 53 67 61 59 57 55 51 49 46 38 32 26 21 17 13 07 01 02 05 56 66 64 58 55 48 41 35 26 19 13 67 01 2414.08 2414.17 2414.13 2414.46 2414.45 2414.39 2414.34 2414.23 2414.17 2414.08 2414.01 2413.93 2413.82 2413.75 2413.65 2413.55 2413.43 2413.32 2413.19 2413.09 2412.99 2412.89 2412.76 2412.65 2412.57 2412.45 2412.35 2412.19 —— 2414.46 2412.19 2412.05 2411.93 2411.79 2411.67 2411.56 2411.40 2411.23 2411.08 2410.95 2410.80 2410.64 2410.51 2410.30 2410.11 2409.97 2409.81 2409.65 2409.53 2409.38 2409.19 2409.03 2408.85 2408.68 2408.50 2408.33 2408.13 2408.10 2408.06 2408.10 2408.04 2407.90 2412.05 2407.90 2407.75 2407.60 2407.45 2407.27 2407.04 2406.86 2406.67 2406.49 2406.52 2406.34 2406.16 2405.98 2405.80 2405.61 2405.36 2405.17 2404.97 2404.77 2404.61 2404.33 2404.17 2403.99 2403.79 2403.55 2403.31 2403.09 2402.88 2402.67 2402.45 2402.17 —— 2407.75 2402.17 2402.03 2401.82 2401.67 2401.49 2401.48 2401.48 2401.48 2401.45 2400.20 2399.98 2399.78 2399.52 2399.21 2398.89 2398.54 2398.23 2397.82 2397.48 2397.14 2396.75 2396.40 2396.00 2395.73 2395.39 2394.97 2394.73 2394.98 2394.68 2394.34 2394.03 2393.65 2402.03 2393.65 2393.29 2393.02 2392.86 2392.76 2392.67 2392.57 2392.47 2392.38 2392.28 2392.18 2392.09 2391.89 2391.53 2391.21 2390.85 2390.44 2390.12 2389.89 2389.72 2389.36 2389.00 2388.78 2388.31 2387.94 2387.54 2387.13 2386.79 2386.30 2385.89 2385.45 —— 2393.29 2385.45 2384.98 2384.52 2384.03 2383.63 2383.02 2382.42 2381.91 2381.21 2380.90 2380.19 2379.87 2378.92 2378.12 A A A A A A A A A A A A A A A A A A 2384.98 2378.12 A No gage-height record 59 RIO GRANDE DE ARECIBO BASIN 50020500 RIO GRANDE DE ARECIBO NEAR ADJUNTAS, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°10'54", long 66°44'12", at Highway 135 bridge, 1.0 mi (1.6 km) upstream from Lago Adjuntas, and 1.5 mi (2.4 km) northwest of Adjuntas plaza. DRAINAGE AREA.—12.7 mi' (32.9 km') this does not include 6.0 mi' (15.6 km') above Lago Garzas. PERIOD OF RECORD.—Water years 1969-74, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. ATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEC C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1135 106 230 6.8 21.5 6.5 8.1 94 <10 5200 K19000 .997 1130 18 366 6.8 22.0 0.40 10.0 117 <10 200 310 1130 6.4 414 8.1 27.0 1.0 8.5 112 <10 450 230 0825 37 318 7.5 21.5 4.1 7.9 94 <10 3600 5400 ALKA- DATE NOV 1996 19... FEB 1997 12... JUN 10... SEP 03... DATE NOV 1996 19... FEB 1997 12... JUN 10... SEP 03... DATE NOV 1996 19... FEB 1997 12... JUN 10... SEP 03... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 94 -- 140 110 FLUO- RZDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 0.22 0.40 0.24 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 23 -- 37 30 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 24 -- 36 23 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.4 1.4 1.2 1.8 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 8.9 __ 11 8.7 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 150 — 237 176 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 6.4 6.1 4.0 8.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 26 — 25 16 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 42.8 -- 4.12 17.5 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.040 0.150 0.030 SODIUM AD- SORP- TION RATIO (00931) 1 __ 0.9 0.7 RESIDUE TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) (00530) 10 1 2 36 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.3 — 2.0 2.2 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.30 1.10 1.06 1.60 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 59 120 130 93 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.010 0.040 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- <10 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 1.30 1.20 1.10 1.60 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 11 — 9.9 18 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.020 0.020 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 18 — 38 22 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.21 0.38 0.22 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — ^10 -- K » non-ideal count 60 RIO GRANDE DE ARECIBO BASIN 50020500 RIO GRANDE DE ARECIBO NR ADJUNTAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 19... FEE 1997 12... JUN 10... SEP 03... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 400 — 80 — LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) 1 -- <1 — MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) 30 — 34 — MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) <0.10 -- <0.10 — SELE- NIUM, TOTAL (UG/L AS SE) (01147) <1 — <1 -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) <1 — <1 — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) <10 — <10 -- CYANIDE TOTAL (MG/L AS CN) (00720) <0.010 — <0.010 — PHENOLS TOTAL (UG/L) (32730) 1 — 3 -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 -- 0.02 -- RIO GRANDE DE ARECIBO BASIN 50024950 RIO GRANDE DE ARECIBO BELOW UTUADO, PR LOCATION.—Lat 18°18'07", long 66°42'15", Hydrologic Unit 21010001, 2.4 mi (3.9 km) north of Utuado Plaza, (5.5 km) southwest from Dos Bocas Dam, 3.5 mi (5.6 km) northwest from Caonillas Dam. DRAINAGE AREA.—65.62 mi* (170 km*). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—April 1996 to current year. GAGE.—Water-stage recorder. Elevation of gage is 295.28 ft (90 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. 61 3.4 ml DAY DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC MAR JUN AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN MAX MIN AC-FT CFSM IN. STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1996 - 1996, MEAN MAX (WY) MXN (WY) e53 e53 e55 e79 e89 e58 e60 e62 e57 e52 e51 e49 e45 42 39 —— ___ ___ ___ —— ___ —— BY WATER ___ —— 40 45 48 60 38 38 39 43 52 76 112 62 50 46 49 76 137 64 245 285 193 137 93 do 85 e283 384 213 126 120 106 3425 110 384 38 6790 1.68 1.94 YEAR (WY) 110 110 1996 110 1996 96 88 86 137 251 e!29 e!02 86 70 69 66 61 64 68 132 117 93 91 e462 309 199 118 98 88 81 79 140 83 70 67 —— 3600 120 462 61 7140 1.83 2.04 120 120 1996 120 1996 65 63 61 60 59 57 64 157 254 192 120 129 87 88 111 83 77 74 80 70 e67 e64 63 62 63 61 59 67 87 66 68 2678 86.4 254 57 5310 1.32 1.52 86.4 86.4 1996 86.4 1996 132 e205 e!79 e86 65 61 68 74 61 79 e!37 e237 74 53 59 69 53 56 95 92 62 64 69 148 110 83 71 67 e95 e88 67 2859 92.2 237 53 5670 1.41 1.62 92.2 92.2 1996 92.2 1996 62 60 56 63 219 90 97 80 65 65790 2040 1110 656 775 548 405 432 367 336 273 234 217 204 e!94 e216 191 184 e!78 e316 297 —— 15755 525 5790 56 31250 8.00 8.93 525 525 1996 525 1996 Estimated 62 DAY RIO GRANDE DE ARECIBO BASIN 50024950 RIO GRANDE DE ARECIBO BELOW UTUADO, PR--Continued DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES NOV DEC JAN FEB APR JUN JUL AUG SEP 1 318 e302 2 e221 285 3 e299 268 4 e233 e248 5 147 e231 6 e!61 e200 7 147 e!67 8 116 8138 9 115 e!28 10 109 226 11 104 200 12 101 265 13 176 e324 14 e285 273 15 156 e280 16 156 e327 17 e245 e434 18 e242 463 19 e220 386 20 e234 e345 21 375 8312 22 e272 e228 23 e333 254 24 8262 8222 25 e226 8174 26 242 8131 27 8207 8116 28 8346 ellO 29 271 8103 30 8272 117 31 8362 —— TOTAL 6953 7257 MEAN 224 242 MAX 375 463 MIN 101 103 AC-FT 13790 14390 CFSM 3.42 3.69 IN. 3.94 4.11 STATISTICS OF MONTHLY MEAN MEAN 224 242 MAX 224 242 (WY) 1997 1997 MIN 224 242 (WY) 1997 1997 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 8105 elOO 899 8106 8114 118 111 8114 8127 134 277 8165 8151 151 148 139 131 120 8109 8105 107 115 128 105 90 86 88 84 82 879 79 3667 118 277 79 7270 1.80 2.08 DATA 118 118 1997 118 1997 75 75 890 895 86 90 75 80 77 80 74 74 77 107 82 874 71 70 90 161 253 344 220 214 183 164 151 139 127 112 100 3710 120 344 70 7360 1.82 2.10 FOR WATER 120 120 1997 120 1997 95 105 99 90 87 96 143 87 85 82 87 82 85 84 85 78 80 82 83 78 73 71 70 69 68 66 64 63 ___ —— 2337 83.5 143 63 4640 1.27 1.32 YEARS 1996 - 83.5 83.5 1997 83.5 1997 FOR 1997 62 61 66 83 90 76 68 68 61 62 62 64 65 65 65 65 64 73 103 78 60 60 56 56 855 856 e58 889 e77 874 867 2109 68.0 103 55 4180 1.04 1.20 1997 68.0 68.0 1997 68.0 1997 56 855 62 53 51 50 49 48 48 47 46 46 45 44 44 43 43 42 41 41 43 66 844 40 38 39 40 41 40 40 —— 1385 46.2 66 38 2750 .70 .79 , BY WATER 46.2 46.2 1997 46.2 1997 42 84 86 44 40 40 40 39 61 57 41 40 38 38 39 39 38 37 36 37 40 54 48 72 101 71 46 50 36 39 103 1576 50.8 103 36 3130 .77 .89 YEAR (WY) 80.7 110 1996 50.8 1997 53 41 39 37 36 36 835 834 833 832 831 830 830 829 829 829 828 829 32 44 855 58 42 55 29 62 88 42 37 68 —— 1223 40.8 88 28 2430 .62 .69 80.4 120 1996 40.8 1997 WATER YEAR 37 31 30 31 31 33 34 59 64 40 36 35 33 32 42 32 28 39 41 34 46 33 30 28 26 30 26 27 64 32 50 1134 36.6 64 26 2250 .56 .64 61.5 86.4 1996 36.6 1997 WATER 30 26 33 37 26 24 23 34 106 61 50 32 240 327 138 112 82 61 53 86 98 76 116 109 62 48 44 43 56 52 103 2388 77.0 327 23 4740 1.17 1.35 84.6 92.2 1996 77.0 1997 YEARS 1996 - 440 338 189 91 88 103 60 55 52 51 50 61 70 58 101 52 48 46 44 44 45 45 44 67 61 45 67 53 94 58 —— 2620 87.3 440 44 5200 1.33 1.49 306 525 1996 87.3 1997 1997 36359 99. 463 23 28 4700 9. 22 6 31 Nov 18 Aug 7 Aug 1 Sep 1 Sep 1 Aug 7 72120 1. 20. 236 70 34 52 61 99 99 99 5790 23 28 25900 19 22 72170 1 20 245 74 37 .6 .6 .6 Sep 10 Aug 7 Aug 1 Sep 10 .03 Sep 10 Aug 7 .52 .63 1997 1997 1996 1997 1997 1996 1996 1997 e Estimated RIO GRANDE DE ARECIBO BASIN 63 50024950 RIO GRANDE DE ARECIBO BELOW UTUADO, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— April, 1996 to current water year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: April, 1996 to current water year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1996. REMARKS.-- Sediment samples were collected by a local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 10,600 mg/L September 10, 1996; Minimum daily mean, 3 mg/L August 6, 1996. SEDIMENT LOADS: Maximum daily mean, 201,000 tons (183,300 tonnes) September 10, 1996; Minimum daily mean, 0.50 ton (0.45 tonne) August 6, 1996. EXTREMES FOR CURRENT YEAR 1997. SEDIMENT CONCENTRATION: Maximum daily mean, 4,620 mg/L September 2, 1997; Minimum daily mean, 11 mg/L June 14, 1997. SEDIMENT LOADS: Maximum daily mean, 9,140 tons (8,290 tonnes) September 1, 1997; Minimum daily mean, 0.87 ton (0.79 tonne) June 14, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAY MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) APRIL SEDIMENT DISCHARGE (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL e53 e53 e55 e79 e89 e58 e60 e62 e57 e52 e51 e49 e45 42 39 143 112 87 763 370 77 77 76 68 68 67 65 62 62 63 e20 el 6 el3 e363 el35 el 3 el3 el3 elO e9.4 e9 e8 e7 7 6.7 MEAN DISCHARGE (CFS) 40 45 48 60 38 38 39 43 52 76 112 62 50 46 49 76 137 64 245 285 193 137 93 80 85 e283 384 213 126 120 106 3425 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 62 61 64 74 60 58 59 60 382 151 949 125 68 64 66 82 505 78 1200 2030 134 111 95 90 90 1970 2610 1110 112 585 99 6.8 7.4 8.6 12 6.1 6.0 6.2 6.9 123 36 835 24 9.1 8.1 9.0 18 408 14 3150 1870 70 41 24 20 21 63570 5130 695 38 304 28 16505.2 MEAN DISCHARGE (CFS) 96 88 86 137 251 el29 el02 86 70 69 66 61 64 68 132 117 93 91 e462 309 199 118 98 88 81 79 140 83 70 67 3600 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 93 90 88 482 2520 679 92 33 24 24 23 22 21 21 558 111 92 92 3640 895 592 403 274 187 127 87 59 42 40 40 24 22 20 433 2180 6415 625 7.8 4.6 4.4 4.1 3.7 3.7 3.8 471 36 23 23 67290 785 321 130 73 44 28 18 22 9.5 7.6 7.2 12439.4 e Estimated 64 RIO ORANDB DE ARECIBO BASIN 50024950 RIO ORANDE DE ARECIBO BELOW UTUADO, PR— Continued SEDIMENT DISCBAROE, SUSPENDED (TONS/DAY) , HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MO/L) (TONS /DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 65 63 61 60 59 57 64 157 254 192 120 129 87 88 111 83 77 74 80 70 •67 •64 63 62 63 61 59 67 87 66 68 JULY 40 40 39 39 39 39 54 118 158 137 108 183 93 87 85 84 83 82 86 81 79 78 78 77 77 76 76 80 79 66 69 7.0 6.7 6.5 6.4 6.2 6.0 10 53 108 72 35 109 22 21 25 19 17 16 19 15 •14 •13 13 13 13 13 12 15 19 12 13 MEAN DISCHARGE (CFS) 132 •205 •179 •86 65 61 68 74 61 79 •137 •237 74 53 59 69 53 56 95 92 62 64 69 148 110 83 71 67 •95 •88 67 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 651 1140 235 23 5 3 8 80 46 63 1040 2010 89 65 48 38 32 27 23 183 158 126 99 1110 72 44 41 40 1710 2740 1040 TOTAL 2678 729.8 2859 421 •678 •122 •6.0 .84 .50 2.0 16 7.5 15 •961 •3520 18 9.2 7.7 7.2 4.6 4.1 5.9 189 27 22 18 1530 22 9.8 7.6 7.4 •614 •665 189 9107.34 MEAN DISCHARGE (CFS) 62 60 56 63 219 90 97 80 65 5790 2040 1110 656 775 548 405 432 367 336 273 234 217 204 •194 •216 191 184 •178 •316 297 15755 MEAN CONCEN- TRATION (MO/L) 441 190 108 241 2360 1510 381 187 105 10600 4990 999 280 2780 5080 522 2130 1040 473 438 273 170 185 153 1190 747 264 249 236 1330 SEDIMENT DISCHARGE (TONS/DAY) 74 31 16 56 4450 384 102 41 19 201000 29000 3190 513 11200 7590 592 2920 1040 429 324 173 99.8 102 •80 •851 391 131 •134 •184 1490 266606.8 • Estimated RIO GRANDE DE ARECIBO BASIN 50024950 RIO GRANDE DE ARECIBO BELOW UTUADO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN DISCHARGE (CPS) CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MQ/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL 318 a221 a299 a233 147 a!61 147 116 115 109 104 101 176 a285 156 156 a245 8242 0220 a234 375 a272 8333 8262 a226 242 8207 a346 271 0272 8362 6953 OCTOBER 752 138 136 146 156 164 165 132 94 73 75 72 1290 834 119 112 2320 1380 337 191 1430 148 145 142 139 488 173 1670 2200 1710 2440 736 a86 alOl a91 62 a70 65 41 29 21 21 20 1460 e!060 50 47 e3070 a980 a201 a!21 5250 a!09 a!30 a!02 a85 481 a99 a!960 1590 a!270 e4800 24208 a302 285 268 a248 a231 a200 a!67 a!38 a!28 226 200 265 a324 273 a280 a327 a434 463 386 a345 a312 a228 254 a222 e!74 a!31 el!6 ellO a!03 117 NOVEMBER 311 115 90 71 48 32 27 24 22 1260 140 1710 896 170 394 681 1270 1600 308 161 773 1500 151 174 200 231 267 307 327 197 DECEMBER 7257 a252 89 65 e48 e30 e!7 e!2 a9.1 a7.7 1140 77 2500 a? 95 126 a369 a865 a3710 2880 322 a!49 al!70 a!240 103 a!04 e93 e82 e83 e91 e91 61 16580.8 elOS elOO e99 el06 el!4 118 111 el!4 e!27 134 277 e!65 e!51 151 148 139 131 120 e!09 elOS 107 115 128 105 90 86 88 84 82 e79 79 3667 108 94 96 117 144 138 123 110 241 213 1270 122 87 65 65 67 70 60 58 76 77 74 385 122 109 107 106 91 75 58 44 e31 e25 e26 e33 e45 44 37 e34 e!98 86 1130 e54 e35 26 26 25 25 20 e!7 e21 22 23 184 34 26 25 25 21 17 e!2 9.4 2336.4 e Estimated 66 RIO GRANDE DE ARECIBO BASIN 50024950 RIO GRANDE DE ARECIBO BELOW UTUADO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 75 75 e90 e95 86 90 75 80 77 80 74 74 77 107 82 e74 71 70 90 161 253 344 220 214 183 164 151 139 127 112 100 MEAN CONCEN- SEDIMENT TRATXON DISCHARGE (MG/L) (TONS/DAY) JANUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 75 75 e90 e95 86 90 75 80 77 80 74 74 77 107 82 e74 71 70 90 161 253 344 220 214 183 164 151 139 127 112 100 32 23 44 79 94 47 26 39 77 46 26 14 12 139 83 51 33 25 402 847 1540 1670 553 411 293 206 137 47 36 34 28 6.5 4.7 e!3 e21 22 12 5.3 9.2 16 10 5.1 2.9 2.4 68 19 elO 6.3 4.8 229 555 1570 2120 330 238 145 92 56 18 12 10 7.7 95 105 99 90 87 96 143 87 85 82 87 82 85 84 85 78 80 82 83 78 73 71 70 69 68 66 64 63 23 46 92 59 39 189 684 169 292 267 195 142 105 89 2610 1560 693 463 320 164 85 164 432 986 791 501 390 321 5.9 15 25 15 9.2 99 362 39 67 59 46 32 24 20 636 330 149 102 72 35 17 31 81 184 146 90 67 54 MEAN DISCHARGE (CFS) 62 61 66 83 90 76 68 68 61 62 62 64 65 65 65 65 64 73 103 78 60 60 56 56 e55 e56 e58 e89 e77 e74 e67 MEAN CONCEN- TRATION (MQ/L) MARCH 211 127 84 3150 2560 1510 1490 350 777 2250 1340 582 508 576 1480 3210 1820 815 2080 750 181 138 125 112 101 90 79 1650 788 498 462 SEDIMENT DISCHARGE (TONS/DAY) 35 21 15 867 622 399 276 64 129 377 225 100 89 100 259 566 315 164 1020 175 30 22 19 17 e!5 e!4 e!3 e453 e!61 e95 e85 TOTAL 3710 5620.9 2337 2812.1 2109 6742 e Estimated RIO GRANDE DE ARECIBO BASIN 50024950 RIO GRANDE DE ARECIBO BELOW UTOADO, PR—Continued DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 67 DAY DISCHARGE (CTS) TRATION DISCHARGE (MQ/L) (TONS/DAY) APRIL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL 56 •55 62 53 51 50 49 48 48 47 46 46 45 44 44 43 43 42 41 41 43 66 •44 40 38 39 40 41 40 40 287 186 183 187 119 74 66 49 40 47 42 35 33 33 34 35 43 56 60 60 60 1110 87 76 43 22 19 21 22 21 43 •27 31 27 17 9.9 8.7 6.4 5.2 5.9 5.2 4.3 4.0 4.0 4.0 4.0 5.1 6.4 6.7 6.6 7.0 477 •10 8.2 4.5 2.3 2.1 2.3 2.4 2.3 1385 749.5 DISCHARGE (crs) 42 84 86 44 40 40 40 39 61 57 41 40 38 38 39 39 38 37 36 37 40 54 48 72 101 71 46 50 36 39 103 1576 CONCEN- SEDIMENT TRATION DISCHARGE (MQ/L) (TONS/DAY) MAY 20 1470 2340 256 147 121 98 80 2330 661 251 316 129 37 30 36 71 149 93 39 42 817 579 1710 2000 1280 68 145 142 80 938 2.3 651 717 31 16 13 11 8.4 507 134 28 34 13 3.9 3.1 3.7 7.2 15 9.1 3.9 4.7 174 76 493 1640 429 8.4 20 14 8.3 1800 6879.0 DISCHARGE (CFS) 53 41 39 37 36 36 •35 •34 •33 •32 •31 •30 •30 •29 •29 •29 •28 •29 32 44 •55 58 42 55 29 62 88 42 37 68 1223 TRATION DISCHARGE (MG/L) (TONS/DAY) 76 43 32 25 20 16 14 15 18 15 12 13 16 11 16 28 27 23 20 550 562 451 923 526 43 1520 1540 63 71 1160 11 4.7 3. 2. 2. 1. •1. •1. •1. •1. • .98 •1.1 •1.3 • .87 •1.2 •2.2 •2.1 •1.8 1.8 162 •222 114 150 134 3.4 551 746 7.2 7.4 689 2830.15 • Eitinat*d 68 RIO GRANDE DE ARECIBO BASIN 50024950 RIO GRANDE DE ARECIBO BELOW UTUADO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN BAN CONCEN- SEDIMENT URGE TRATION DISCHARGE PS) (MG/L) (TONS/DAY) JULY 37 31 30 31 31 33 34 59 64 40 36 35 33 32 42 32 28 39 41 34 46 33 30 28 26 30 26 27 64 32 50 1134 6359 85 54 38 24 21 22 32 62 76 48 27 16 15 24 346 370 125 62 63 58 159 102 62 37 28 36 43 39 2660 4410 2680 —— 9.2 4.5 3.1 2.0 1.8 1.9 3.0 13 14 5.3 2.6 1.5 1.3 2.3 67 32 9.4 7.0 7.5 5.3 20 9.2 5.0 2.8 2.0 3.0 3.0 3.0 998 386 439 2064.7 104156.65 MEAN DISCHARGE (CPS) 30 26 33 37 26 24 23 34 106 61 50 32 240 327 138 112 82 61 53 86 98 76 116 109 62 48 44 43 56 52 103 MEAN CONCEN- TRATION (MG/L) AUGUST 2230 768 1190 1830 330 221 116 65 1680 462 70 57 2500 3200 2020 859 105 130 170 809 731 319 1760 379 129 87 72 63 595 62 93 SEDIMENT DISCHARGE (TONS/DAY) 187 53 142 224 23 14 7.2 6.5 1800 176 9.9 5.0 5330 6360 815 330 23 21 24 351 318 70 1170 142 22 11 8.6 7.3 196 9.2 27 MEAN MEAN CONCEN- DISCHARGE TRATION (CPS) 440 338 189 91 88 103 60 55 52 51 50 61 70 58 101 52 48 46 44 44 45 45 44 67 61 45 67 53 94 58 (M6/L) SEPTEMBER 1530 4620 795 152 119 283 121 52 41 44 76 105 79 198 186 152 94 57 74 131 229 376 206 100 142 131 1450 68 751 80 ___ SEDIMENT DISCHARGE (TONS/DAY) 9140 4230 521 38 34 85 20 7.7 5.8 6.1 10 17 16 62 51 21 12 7.1 8.9 15 28 46 25 21 23 16 504 9.8 457 13 ___ 2388 17882.7 2620 15450.4 RIO GRANDE DE ARECIBO BASIN 50024950 RIO GRANDE DE ARECIBO BELOW UTUADO, PR--Continued 69 WATER QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 199 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. DATE OCT 1996 13... 17... 21... NOV 10... APR 1997 22... 22... MAY 24... 25... JUN 02... 26... 26... JUL 29... 31... AUG 13... 21... SEP 27... DATE OCT 1996 13... 17... 21... NOV 10... APR 1997 22... 22... MAY 24... 25... JUN 02... 26... 26... JUL 29... 31... AUG 13... 21... SEP 27... TIME 2400 1745 1710 1800 1700 1800 1630 1730 1336 1701 1720 1833 1735 1531 1715 1800 SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) 75 47 39 50 42 44 47 37 46 73 62 63 79 45 63 59 CHARGE, INST. CUBIC FEET PER SECOND (00061) 336 915 3000 283 81 231 79 365 40 200 204 220 73 1440 177 242 SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) 83 60 48 59 52 58 56 49 61 83 75 78 84 56 79 72 SEDI- MENT, SUS- PENDED (MG/L) (80154) 10100 25100 12800 7000 10200 14500 13700 20000 9230 7440 8160 11000 2060 13800 10200 8640 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 97 80 60 74 71 77 71 73 82 94 91 93 97 81 95 88 MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 9460 62000 104000 5350 2230 9030 2920 19700 997 4020 4490 6530 406 5360 4880 5650 SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM (70332) 98 95 73 93 91 98 87 93 97 99 98 99 99 97 99 98 SUSP. FALL DIAM. * FINER THAN .002 MM (70326) 36 23 16 22 20 20 22 18 24 36 28 32 48 20 33 25 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 97 84 99 99 100 99 100 99 100 100 100 100 99 100 99 SUSP. FALL DIAM. * FINER THAN .004 MM (70327) 48 29 22 30 24 26 28 21 28 44 35 34 57 28 39 34 SED. SUSP. SIEVE DIAM. H FINER THAN .500 MM (70334) 100 97 95 100 100 100 100 100 100 100 100 100 100 99 100 99 7 SED. SUSP. FALL DIAM. * FINER THAN .008 MM (70328) 59 36 32 38 32 32 36 27 35 57 46 48 69 34 50 45 SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 100 98 100 100 100 100 100 100 100 100 100 100 100 100 100 100 86 86 £6 »6 T6 C6 86 88 06 »6 C6 Ci Ti 06 C6 98 SI 98 88 86 L9 86 66 84 £8 86 08 (TCCOi) Ml 890* OC99 0»68 98T CT8 OCC8 0»8C TT 0668 OT»9 OK 098T OOT» OS89 C8T C0» 080T OT»9 OLZL 090» 00«T 00008 0868 00/.CT K 06Ti 06SC OOU 0»S8 OSC9 00»» 008TS L9 TTT 0889 09SS 08C9 09iC 0009 6C9 OCC6 OT»9 OOi6T OOOfT OC98 0080T 08ST 0£9S (SST08) (»ST08) (XTQ/A) (I/OK) 0£T iCT OTC S/.T C8 8CT 99T £08 sc S9C 6L 89 088 88C CTT T»8 86C 09S8 0908 S8C 9T9 90 L (T9000) GNO3K0 OC9T sm OOST ocoo 9»iT 9T9T OCiT OC8T OC8T 00 iT OCiT OCiT OC9T OOCT OOST OS»T OC60 08£T OT9T OOT8 OS9T S»8T CC/.T 9T80 91L1 006T /.too 80T8 XNIA ••'68 •"GO as •'•60 •'•90 OflV "'SI •"98 papp •"68 ••'S8 '••»8 •••OG wm •••»8 ••'18 £661 NVf •"8« 9X0 •"OT AOH •'•68 '•'LI •••n •"GT £90 ••'TT "•OT •••so dXS •"8T OflV •"08 •*'6T 966T HOC xxva HXHU % •mza XAXX8 •dsns -808 -808 'X0HVH9 'AHXII -sia -laxs -laxs 91009 •&8MI -sia 2MXNKIX8 QXQMXd8O8 JO UlXSHXd £66T «MMUdX8 OX S66T VXOOX9O WOO. pvnaT^ttoo—Hd 'OOVOXO WHO OOI9XHV Nzsva oazoxHV xa XYI9 ONV 3.118 HXXVH 'VXTQ XXITVaO ttUYN xa xamrao OXH os6»80os OIH RIO GRANDE DE ARECIBO BASIN 50025000 RIO GRANDE DE ARECIBO NEAR UTUADO, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°18'11", long 66°41'59", at bridge near Highway 10 at km 56.4, 0.5 mi (0.8 km) downstream from Rio de Caguana, and 2.5 mi (4.0 km) north of Utuado plaza. DRAINAGE AREA.--66.0 mi* (170.9 km2 ) this excludes 6.0 mi 2 (15.5 km2 ) upstream from Lago Garzas to Rio Guayanes in the Rio Tallaboa basin. PERIOD OF RECORD.--Water years 1959-74, 1979 to current year WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 71 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. ATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 0845 130 262 6.9 22.5 16 7.7 88 <10 K6600 K1800 L997 1345 85 312 6.2 25.5 5.7 7.4 89 <10 K1500 550 1350 35 320 8.1 22.5 2.5 8.2 108 <10 230 490 1050 215 200 7.0 25.5 260 7.6 93 <10 26000 32000 ALKA- DATE NOV 1996 06... FEB 1997 12... JUN 10... SEP 03... DATE NOV 1996 06... FEB 1997 12... JUN 10... SEP 03... DATE NOV 1996 06... FEB 1997 12... JUN 10... SEP 03... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 100 -- 120 71 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- 0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.36 0.46 0.45 0.81 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 27 — 32 19 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 30 — 31 19 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.7 2.2 1.7 2.2 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 8.1 -- 8.7 5.5 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 170 -- 195 117 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 7.6 9.5 7.6 9.5 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 12 — 16 9.7 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 59.5 — 18.3 68.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.080 0.120 <0.020 0.330 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 0.7 0.5 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 26 30 4 344 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.3 — 2.6 2.7 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.30 1.57 1.10 1.30 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 92 93 97 57 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.130 0.160 0.014 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- <10 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.30 1.70 1.30 1.30 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 __ <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 22 -- 30 16 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.180 0.090 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 13 -- 17 11 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.34 0.28 0.36 0.78 COPPER, TOTAL RECOV- ERABLE (UG/L AS CO) (01042) 10 — <10 — K « non-ideal count 72 RIO GRANDE DE ARECIBO BASIN 50025000 RIO GRANDE DE ARECIBO NEAR OTUADO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 06... FEB 1997 12... JUN 10... SEP 03... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 1400 160 <1 90 17 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <0.01 <0.01 RIO GRANDE DE ARECIBO BASIN 50025155 RIO SALIENTE AT COABEY NEAR JAYUYA, PR 73 LOCATION.—Lat 18°12'48", long 66°33'49", Hydrologic unit 21010002, 2.0 ml (3.2 tan) southeast of Jayuya, 1.4 ml (2.2 tan) northeast of Hacienda Gripinas. DRAINAGE AREA.—9.25 ml* (23.96 JOB* ) . PERIOD OF RECORD.—October 1989 to current year. GAGE.—Water-stage recorder. Elevation of gage Is 1,706 ft (520 m), from topographic map. REMARKS.—Records fair except those for estimated dally discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER DAY OCT NOV 1 e!6 e!9 2 e!3 e!3 3 e!8 e!2 4 e!4 ell 5 e!3 elO 6 e!8 elO 7 e!3 ell 8 ell e8.4 9 elO e!7 10 elO e!6 11 elO e!9 12 e9.6 e!7 13 e9.6 e!3 14 e9.0 e9.4 15 e9.4 e8.2 16 ell elO 17 e!5 e50 18 e!5 e58 19 e!6 e33 20 e!5 e26 21 e!4 e49 22 e!2 e37 23 elO e34 24 e9.2 e32 25 e8.8 e24 26 ell e20 27 e20 e!8 28 e23 e!7 29 e!7 e!6 30 e!4 e!8 31 e20 TOTAL 414.6 636.0 MEAN 13.4 21.2 MAX 23 58 KIN 8.8 8.2 AC-FT 822 1260 CFSM 1.45 2.29 IN. 1.67 2.56 STATISTICS OF MONTHLY MEAN MEAN 38.6 24.4 MAX 72.0 40.0 (WY) 1996 1991 MIN 11.6 10.0 (WY) 1992 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC •17 •15 •14 •14 •13 •13 •12 •12 ell ell •58 •40 •34 •29 •27 •26 •23 •22 •22 •21 •21 •20 •19 •18 •18 •18 •18 •17 •18 •18 •18 637 20.5 58 11 1260 2.22 2.56 JAN •17 •17 •33 •32 •22 •18 •17 •15 •15 •15 •15 •15 •15 •20 •17 •15 •14 •14 •24 •30 •140 •110 •60 •45 •38 •31 •27 •25 •23 •21 •20 920 29.7 140 14 1820 3.21 3.70 DATA FOR WATER 13.2 22.7 1993 5.97 1995 FOR 19.7 48.1 1992 4.13 1995 DAILY FEB •20 •20 •19 e!8 •18 •18 •17 •16 •16 •15 •15 •14 •14 •13 •13 •12 •12 •12 •13 •12 •12 ell ell elO •11 ell elO elO —— —— —— 393 14.0 20 10 780 1.52 1.58 YEARS 1989 15.9 44.4 1996 4.67 1994 1996 CALENDAR YEAR 21343. 58. 4700 4. 5. 42330 6. 85. 75 17 8. 0 3 Sep 10 7 Jan 12 5 Jan 1 30 83 6 1996 TO SEPTEMBER 1997 MEAN VALUES MAR elO elO elO elO 10 9.5 9.0 9.8 9.4 8.7 8.2 8.0 8.0 7.8 7.6 7.6 7.4 7.2 7.3 6.9 6.8 6.4 6.1 6.0 5.8 5.7 5.8 6.7 14 13 8.7 257.4 8.30 14 5.7 511 .90 1.04 - 1997, 10.8 15.5 1996 4.79 1994 APR 8.2 8.1 11 8.8 8.2 7.7 7.2 6.8 6.6 6.6 6.2 6.0 5.7 5.6 5.5 5.4 5.3 5.1 4.9 4.9 4.9 5.1 4.9 4.7 4.5 4.5 4.2 4.1 4.1 4.0 —— 178.8 5.96 11 4.0 355 .64 .72 MAY 4.2 6.0 5.2 5.2 4.2 4.2 5.1 4.1 22 20 6.9 5.4 .6 .4 .5 .3 .6 .3 3.8 3.8 3.8 3.8 4.7 4.7 4.7 33 83 43 12 8.2 7.4 335.1 10.8 83 3.8 665 1.17 1.35 JUN 6.8 6.3 5.8 5.8 5.8 5.7 5.1 4.7 4.3 4.3 4.3 4.0 4.0 4.3 4.0 3.6 3.6 4.0 10 7.9 4.6 4.0 3.8 3.7 3.6 6.4 11 7.7 5.0 4.8 —— 158.9 5.30 11 3.6 315 .57 .64 JUL 4.5 4.1 3.9 3.6 3.4 3.3 3.5 3.9 3.6 3.5 3.4 4.0 4.9 3.9 3.7 3.9 3.5 4.1 5.4 24 15 7.4 5.3 4.3 4.1 3.8 3.6 3.4 3.2 3.2 19 170.4 5.50 24 3.2 338 .59 .69 AUG 7.2 4.0 5.3 7.1 4.2 3.5 3.1 58 132 43 20 24 85 110 65 26 19 14 11 10 11 11 28 25 15 11 28 62 30 19 15 906.4 29.2 132 3.1 1800 3.16 3.65 SEP 15 34 28 17 15 14 12 11 9.5 8.9 8.5 9.6 9.8 7.9 7.6 7.3 7.0 6.9 6.6 6.3 6.8 7.6 7.0 20 18 10 12 11 43 21—— 398.3 13.3 43 6.3 790 1.44 1.60 BY WATER YEAR (WY) 20.4 46.4 1993 5.95 1994 37.9 98.6 1995 5.35 1990 21.8 35.4 1994 5.30 1997 FOR 1997 WATER YEAR 5405.9 14.8 140 3.1 3.5 unknown unknown 3.0 10720 1.60 21.74 27 10 4.0 Jan 21 Aug 7 Jul 5 Jan 21 Jan 21 Aug 7 16.8 50.9 1996 2.83 1994 WATER 27 64 10 4700 2 2 14500 19 2 19940 2 40 47 12 4 23.0 49.0 1995 9.82 1994 YEARS 1989 .5 .0 .9 Sep .3 Jul .5 Jul Sep .29 Sep .1 Jul .98 .44 .4 88.4 365 1996 10.8 1994 - 1997 1996 1994 10 1996 27 1994 23 1994 10 1996 10 1996 26 1994 e Estimated 74 RIO GRANDE DB ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR LOCATION.--Lat 18°13'53", long 66»38'14", Hydrologic Unit 21010001, 3.5 mi (5.6 km) south of Lago Caonillas Dan, 4.8 mi (7.72 tan) southeast of Utuado Plaza and 2.78 mi (4.47 JOB) east of Lago Vivi Dan. DRAINAGE AREA.--37.94 mi* (98.26 km*). NATER-DISCHAROE RECORDS PERIOD OF RECORD.—October 1995 to current year. GAGE.—Water-stage recorder. Elevation of gage is 984 ft (300 m), from topographic aap. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO DAILY MEAN VALUES OCT NOV DEC JAN MAR APR MAY JUN 1996 JUL AUG SEP 1 133 e90 2 119 e88 3 159 e88 4 164 e90 5 170 88 6 117 98 7 106 95 8 97 93 9 92 110 10 90 131 11 129 93 12 147 82 13 153 116 14 99 99 15 88 129 16 149 158 17 129 112 18 139 93 19 136 83 20 301 79 21 333 73 22 214 75 23 163 73 24 e381 63 25 e315 62 26 244 66 27 e!69 65 28 e!20 59 29 elSO 55 30 e!20 54 31 elOO —— TOTAL 5026 2660 MEAN 162 88.7 MAX 381 158 MIN 88 54 AC-FT 9970 5280 CFSM 4.27 2.34 IN. 4.93 2.61 STATISTICS OF MONTHLY MEAT MEAN 162 88.7 MAX 162 88.7 (WY) 1996 1996 MIN 162 88.7 (WY) 1996 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 53 52 SO 48 48 47 47 47 47 46 52 48 48 45 45 44 43 49 60 48 44 42 41 41 40 40 SO 57 43 40 38 1443 46.5 60 38 2860 1.23 1.41 I DATA 46.5 46.5 1996 46.5 1996 37 35 34 33 33 36 34 33 37 34 31 30 35 99 167 62 45 39 38 SO 45 35 33 31 37 62 98 92 70 55 46 1546 49.9 167 30 3070 1.31 1.52 FOR WATER 49.9 49.9 1996 49.9 1996 42 38 37 35 33 33 82 76 47 83 94 48 41 37 35 33 41 41 36 35 186 214 491 240 130 89 73 66 59 —— —— 2495 86.0 491 33 4950 2.27 2.45 YEARS 1996 - 86.0 86.0 1996 86.0 1996 FOR 1996 53 49 46 e4S e4S 44 e40 e37 e!20 e94 e!30 elOO eS8 eSO e66 e62 eS8 e47 e42 e40 e37 e33 e33 e32 e32 e32 e31 e30 e30 39 36 1591 51.3 130 30 3160 1.35 1.56 1996, BY 51.3 51.3 1996 51.3 1996 33 29 124 202 111 90 59 49 44 41 40 83 83 59 59 51 47 e48 e64 eS6 e47 e44 e37 e35 e3S e32 e30 e30 e28 e28 —— 1718 57.3 202 28 3410 1.51 1.68 WATER 57.3 57.3 1996 57.3 1996 e2S e25 31 28 23 23 23 24 25 25 25 24 27 34 38 e!90 e240 e90 e350 e!200 e250 e84 e90 e54 e43 e48 e42 e36 e32 e600 e!70 3919 126 1200 23 7770 3.33 3.84 YEAR (WY) 126 126 1996 126 1996 e82 e60 eSO e200 e!40 ellO e66 eS6 e48 e46 e39 e34 e34 e29 eSOO e98 eS4 e!90 142 68 SO 46 44 41 39 38 38 e35 e32 e32 —— 2441 81.4 500 29 4840 2.14 2.39 81.4 81.4 1996 81.4 1996 e29 e26 e2S e26 e26 e2S e26 e!200 e920 141 81 66 eS7 78 127 73 60 54 SO 47 e44 41 40 39 39 37 36 59 77 42 39 3630 117 1200 25 7200 3.09 3.56 117 117 1996 117 1996 107 121 73 48 41 37 36 35 33 38 70 66 45 37 35 36 33 38 52 SO 48 35 e32 74 59 40 e36 e3S e34 e32 30 1486 47.9 121 30 2950 1.26 1.46 47.9 47.9 1996 47.9 1996 31 29 65 e90 139 59 43 60 eS8 eS360 e2400 e498 316 385 295 224 202 e!7S 155 138 121 111 105 97 100 96 90 e89 e85 89 —— 11705 390 5360 29 23220 10.3 11.48 390 390 1996 390 1996 WATER YEAR 39660 108 5360 23 24 22100 26. 22 Sep May May Sep 10 Sep May 10 5 5 10 10 5 78670 2. 38. 163 SO 32 86 89 e Estimated DAY RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEE MAY JUN JUL 75 SEP 1 85 100 2 672 71 3 e98 64 4 88 e59 5 70 56 6 elOO 855 7 69 59 8 61 e45 9 57 895 10 54 86 11 56 102 12 852 93 13 852 e72 14 49 853 15 51 844 16 58 46 17 81 e258 18 79 8310 19 84 186 20 79 141 21 76 e269 22 64 e204 23 56 180 24 50 176 25 47 130 26 55 109 27 110 96 28 125 93 29 95 685 30 75 97 31 113 —— TOTAL 2261 3434 MEAN 72.9 114 MAX 125 310 MIN 47 44 AC -FT 4480 6810 CFSM 1.92 3.02 IN. 2.22 3.37 STATISTICS OF MONTHLY MEAN MEAN 118 102 MAX 162 114 (WY) 1996 1997 MIN 72.9 88.7 (WY) 1997 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 94 82 76 673 70 668 664 666 660 660 6310 6170 ellO 686 678 678 666 670 666 664 664 662 658 654 654 654 e54 652 e54 654 654 2425 78.2 310 52 4810 2.06 2.38 DATA 62.4 78.2 1997 46.5 1996 652 652 698 698 664 654 652 644 644 e44 644 644 644 660 850 642 642 642 672 690 6420 6350 6190 6135 116 94 80 74 69 63 61 2784 89.8 420 42 5520 2.37 2.73 FOR WATER 69.8 89.8 1997 49.9 1996 61 60 59 54 653 53 51 ' 48 47 46 44 43 41 39 38 36 35 35 38 37 36 35 32 31 33 31 • 30 28 ___ ___ --- 1174 41.9 61 28 2330 1.11 1.15 YEARS 1996 64.4 86.0 1996 41.9 1997 28 28 28 28 29 28 28 30 29 26 25 27 26 25 25 25 24 25 26 23 22 21 20 20 19 20 20 22 e37 38 e26 798 25.7 38 19 1580 .68 .78 - 1997 38.5 51.3 1996 25.7 1997 FOR 1996 CALENDAR YEAR 38651 106 5360 23 24 76660 2. 37. 159 54 32 Sep 10 May 5 May 5 78 90 623 623 628 625 623 622 621 620 e!9 619 619 618 e!8 e!7 617 e!7 e!5 e!5 614 e!4 e!4 815 e!4 13 12 11 11 11 11 11 —— 510 17.0 28 11 1010 .45 .50 12 48 37 18 14 14 15 13 51 643 622 e!9 617 e!6 e!6 14 15 14 13 13 13 13 27 31 636 45 135 93 29 20 37 903 29.1 135 12 1790 .77 .89 39 22 19 17 16 16 16 15 14 14 13 13 14 13 11 11 11 e!4 22 25 14 13 11 11 11 11 19 20 20 18 —— 483 16.1 39 11 958 .42 .47 14 12 11 10 11 10 10 17 17 13 11 12 14 12 12 13 12 12 14 26 55 24 18 15 14 14 12 12 11 12 32 482 15.5 55 10 956 .41 .47 30 15 15 21 15 13 12 121 6177 90 51 34 206 269 6162 73 54 42 34 30 36 36 45 76 39 31 38 67 57 34 27 1950 62.9 269 12 3870 1.66 1.91 54 100 79 45 40 36 30 26 24 22 21 25 29 22 21 20 18 18 17 17 17 20 18 46 53 27 24 26 47 55 997 33.2 100 17 1980 .88 .98 , BY WATER YEAR (WY) 37.1 57.3 1996 17.0 1997 FOR 1997 18201 49 420 10 11 unknown unknown 9 36100 1 17 95 36 13 77.8 126 1996 29.1 1997 WATER YEAR .9 Jan 21 Jul 4 Jul 1 Jan 21 Jan 21 .5 Jul 6 .31 .85 48.7 81.4 1996 16.1 1997 66.3 117 1996 15.5 1997 WATER 79 108 49 5360 10 11 22100 26 9 57340 2 28 130 45 16 55.4 62.9 1997 47.9 1996 YEARS 1996 - .2 .9 Sep 10 Jul 4 Jul 1 Sep 10 .10 Sep 10 .5 Jul 6 .09 .35 212 390 1996 33.2 1997 1997 1996 1997 1996 1997 1997 1996 1996 1997 e Estimated 76 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CACHILLAS AT PASO PALMA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- October, 1995 to current water year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October, 1995 to current water year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1996. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 24,700 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 495,000 tons (449,000 tonnes) September 10, 1996; Minimum daily mean, 0.08 ton (0.07 tonne) June 14, 1997. EXTREMES FOR WATER YEARS 1996-1997. SEDIMENT CONCENTRATION: Maximum daily mean, 24,700 mg/L September 10, 1996; Minimum daily mean, 1 mg/L June 26-27 and July 17, 1996. SEDIMENT LOADS: Maximum daily mean, e495,000 tons (e449,000 tonnes) September 10, 1996; Minimum daily mean, 0.13 ton (0.12 tonne) June 26, 1996. SEDIMENT CONCENTRATION: Maximum daily mean, 1,220 mg/L November 22, 1996; Minimum daily mean, 1 mg/L February 17, 1997. SEDIMENT LOADS: Maximum daily mean, el,570 tons (el,420 tonnes) November 17, 1996; Minimum daily mean, 0.08 ton (0.07 tonne) June 14, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 133 119 159 164 170 117 106 97 92 90 129 147 153 99 88 149 129 139 136 301 333 214 163 e381 e315 244 e!69 e!20 elSO e!20 elOO 217 261 367 313 133 32 25 27 32 83 227 217 284 46 50 248 286 287 234 601 940 242 198 494 711 108 55 64 84 85 85 91 85 236 165 76 10 7.1 7.1 7.8 22 103 124 139 12 12 202 123 157 94 1250 1160 156 87 e438 e!090 75 e25 e20 e30 e31 e25 e90 e88 e88 e90 88 98 95 93 110 131 93 82 116 99 129 158 112 93 83 79 73 75 73 63 62 66 65 59 55 54 86 87 88 88 89 111 113 108 158 151 51 64 203 165 244 328 148 105 120 133 107 85 44 20 16 40 50 21 15 15 e22 e21 e21 e21 21 30 30 27 67 64 13 14 105 45 169 155 46 26 27 28 21 18 9 3 2 8 8 3 2 2 .2 .4 .7 .0 .9 .3 .3 .1 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) DECEMBER 53 52 50 48 48 47 47 47 47 46 52 48 48 45 45 44 43 49 60 48 44 42 41 41 40 40 50 57 43 40 38 14 13 12 10 10 10 10 10 10 10 22 44 33 25 19 14 11 18 61 45 33 24 18 17 16 17 51 78 48 43 41 2.0 1.8 1.6 1.3 1.3 1.3 1.3 1.3 1.3 1.2 3.3 5.7 4.3 3.1 2.3 1.7 1.2 2.9 10 5.8 3.9 2.8 2.0 1.9 1.7 1.9 7.0 12 5.7 4.6 4.2 5026 6060.0 2660 1030.9 1443 102.4 e Estimated RIO GRANDE DE ARECZBO BASIN 50026025 RIO CAONXLLAS AT PASO PALMA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 77 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (HG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 37 35 34 33 33 36 34 33 37 34 31 30 35 99 167 62 45 39 38 50 45 35 33 31 37 62 98 92 70 55 46 40 39 38 37 35 34 33 32 33 29 21 12 29 355 194 88 75 63 53 98 51 32 22 15 14 60 125 91 60 40 27 4.0 3.7 3.5 3.3 3.2 3.3 3.1 2.9 3.3 2.6 1.8 .96 2.9 306 117 15 9.0 6.6 5.4 15 6.4 3.1 2.0 1.3 1.4 12 33 23 12 6.0 3.3 FEBRUARY 42 38 37 35 33 33 82 76 47 83 94 48 41 37 35 33 41 41 36 35 186 214 491 240 130 89 73 66 59 —— 19 14 10 7 4 4 136 144 126 221 224 40 23 14 12 11 11 13 17 23 658 850 1040 649 340 157 72 33 20 —— 2.2 1.5 1.0 .63 .38 .31 80 30 16 92 72 5.3 2.6 1.4 1.1 1.0 1.2 1.4 1.7 2.1 1190 956 3180 482 123 38 14 5.8 3.2 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 53 49 46 e45 e45 44 e40 e37 e!20 e94 e!30 elOO e58 eSO e66 e62 e58 e47 e42 e40 e37 e33 e33 e32 e32 e32 e31 e30 e30 39 36 16 12 8 5 5 6 6 5 6 13 27 27 20 21 25 30 35 42 212 46 60 79 104 127 64 23 8 4 10 33 202 2.2 1.5 .94 e.65 e.67 .69 e.60 e.54 el. 2 e3.6 e8.4 e8.3 e4.1 e3.0 e3.9 eS.l e5.7 e5.9 e25 eS.l e6.2 e7.2 e9.2 ell e5.6 e2.0 e.71 e.29 e.83 4.4 21 TOTAL 1546 616.06 2495 6305.82 1591 155.52 e Estimated 78 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (HG/L) (TONS/DAY) 33 29 124 202 111 90 59 49 44 41 40 83 83 59 59 51 47 e48 e64 e56 e47 e44 e37 e35 e35 e32 e30 e30 e28 e28 ___ APRIL 32 21 403 973 341 629 104 14 11 18 35 529 139 14 6 5 22 201 744 52 12 10 10 12 24 81 29 25 13 6 ___ MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) MAY 2.9 1.6 363 927 117 160 17 1.9 1.3 2.0 3.8 126 35 2.2 1.0 .69 2.7 e27 e!32 e8.7 el. 7 el. 2 el.l el.l e2.2 e7.4 e2.4 e2.0 e.99 e.45 ___ e25 e25 31 28 23 23 23 24 25 25 25 24 27 34 38 e!90 e240 e90 e350 e!200 e250 e84 e90 e54 e43 e48 e42 e36 e32 e600 e!70 4 9 29 29 24 19 13 9 6 3 5 9 21 23 39 148 344 398 356 1340 1490 414 160 975 51 48 701 28 17 917 1100 a. 29 e.61 .9 2.2 1.5 1.2 .79 .58 .39 .23 .35 .61 1.7 2.4 9.0 e24 el52 el83 e232 e2280 e!620 el83 e37 e!84 e6.7 e5.9 e85 e3.0 el. 5 e751 el!40 e82 e60 eSO e200 e!40 ellO e66 e56 e48 e46 e39 e34 e34 e29 eSOO e98 e54 e!90 142 68 50 46 44 41 39 38 38 e35 e32 e32 ___ MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE e82 e60 eSO e200 e!40 ellO e66 e56 e48 e46 e39 e34 e34 e29 eSOO e98 e54 e!90 142 68 50 46 44 41 39 38 38 e35 e32 e32 170 33 37 692 156 18 12 12 6 3 3 4 5 6 240 448 76 75 208 121 41 26 16 9 4 1 1 2 14 339 e61 e6.5 e5.5 e210 e75 e6.2 e2.8 e2.1 .89 .42 .40 .40 .45 .50 e218 e385 e!6 e!7 208 23 5.7 3.2 1.9 1.0 .37 .13 .14 e.25 el. 9 e35 1718 1953.33 3919 6912.85 2441 1288.75 e Estimated RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 79 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CTS) •29 •26 •25 •26 •26 •25 •26 •1200 •920 141 81 €6 •57 78 127 73 €0 54 SO 47 •44 41 40 39 39 37 36 59 77 42 39 CONCEN- TRATION DISCHARGE (MO/1,) (TONS/DAY) DI (CFS) TRATION DISCHARGE (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY AUGUST 17 5 2 4 5 6 IS 574 820 201 87 36 9 61 175 3 1 2 5 10 11 12 17 26 36 13 3 58 68 16 24 TOTAL 3630 YEAR 39660 • Estimated •1.4 • .36 • .17 • .26 • .35 • .38 •1.1 •1090 •1220 81 19 €.4 •1.4 21 76 .64 .24 .34 .68 1.3 •1.3 1.3 1.8 2.7 3.7 1.3 .27 28 24 1.8 2.5 2590.69 580520.34 107 121 73 48 41 37 36 35 33 38 70 66 45 37 35 36 33 38 52 SO 48 35 •32 74 59 40 •36 •35 •34 •32 30 1486 279 350 94 53 36 20 10 5 5 27 89 75 34 10 12 16 18 29 55 84 207 38 12 273 96 86 69 24 7 11 25 197 156 21 6.9 4.0 2.0 1.0 .52 .40 3.2 24 IS 4.4 .95 1.1 1.6 1.6 3.4 8.0 IS 28 3.6 •1.5 102 IS 9.4 •6.7 •2.2 • .67 • .98 2.0 639.12 31 29 65 •90 139 59 43 60 •58 •5360 •2400 •498 316 385 295 224 202 •175 155 138 121 111 105 97 100 96 90 •89 •85 89 11705 30 32 251 156 349 S3 13 57 51 24700 4360 16600 14600 9430 663 320 165 85 38 16 16 25 87 278 236 143 113 169 122 185 2.5 2.5 131 •43 223 8.9 1.5 10 •6.6 •495000 •12100 •21400 12500 10200 537 195 90 •40 16 6.1 5.2 7.6 24 73 63 37 27 •41 •28 46 552864.9 80 RIO ORAHDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO 1997 DAY MEAN DISCHARGE (CPS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL 85 e72 e98 88 70 elOO 69 61 57 54 56 652 652 49 51 58 81 79 84 79 76 64 56 50 47 55 110 125 95 75 113 2261 OCTOBER 94 82 141 86 28 37 71 54 43 35 28 23 18 15 24 63 388 99 47 31 72 41 26 28 43 77 239 425 428 315 346 22 617 648 22 5.3 68.2 13 9.0 6.7 5.1 4.2 63.2 e2.5 2.0 3.5 9.9 146 23 11 6.6 16 7.4 4.0 3.8 5.4 13 114 153 111 64 129 988.8 100 71 64 659 56 655 59 e45 e95 86 102 93 e72 653 644 46 e258 e310 186 141 e269 e204 180 176 130 109 96 93 685 97 NOVEMBER 377 84 18 17 17 28 49 36 22 107 140 103 80 50 35 44 623 629 198 85 612 1220 929 382 150 114 98 78 59 45 3434 106 17 3.1 e2.6 2.6 64.3 8.2 64.4 62.8 35 41 26 616 67.3 64.2 5.7 61570 6518 113 32 e895 e678 450 200 53 34 26 20 614 12 4901.2 94 82 76 673 70 668 664 666 660 660 e310 6170 ellO 686 678 678 666 670 666 664 664 662 658 e54 654 654 654 652 654 654 654 2425 29 18 13 10 8 8 13 59 186 69 70 301 34 21 21 52 126 96 137 66 125 34 13 23 37 35 33 44 80 60 124 7.4 4.0 2.6 62.0 1.5 el.5 62.2 elO 632 ell 648 e209 e!3 65.5 64.6 ell 624 618 625 612 622 65.8 el.9 63.4 eS.S eS.l e4.8 66.3 ell e!2 621 543.1 e Estimated RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO FALMA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 81 DAY MEAN DISCHARGE (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL e52 e52 e98 e98 e64 e54 e52 e44 e44 e44 e44 e44 e44 e60 eSO e42 e42 e42 e72 e90 e420 e350 el90 e!35 116 94 80 74 69 63 61 2784 MEAN CONCEN- TRATION (MG/L) JANUARY 44 37 75 65 75 36 19 11 10 9 9 10 15 22 38 101 40 69 55 130 903 424 117 46 23 22 22 22 16 11 15 SEDIMENT DISCHARGE (TONS/DAY) e6.3 eS.l e!5 e!7 e!6 e5.8 e2.8 el.5 el.2 el.l el.l el. 2 el.8 e3.2 eS.5 e!2 e4.5 e7.8 e8.6 e29 e620 e450 e68 e!7 7.2 5.5 4.8 4.4 3.1 1.9 2.4 1330.8 DISCHARGE (CFS) CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 61 60 59 54 e53 53 51 48 47 46 44 43 41 39 38 36 35 35 38 37 36 35 32 31 33 31 30 28 FEBRUARY 26 75 202 137 59 25 12 18 33 29 23 39 74 34 9 3 1 4 12 11 9 8 7 7 9 14 24 25 1174 4.3 12 32 20 e8.5 3.6 1.6 2.3 4.2 3.5 2.8 4.5 8.2 3.7 .94 .29 .13 .36 1.2 1.1 .91 .76 .62 .63 .75 1.2 1.9 1.9 123.89 MEAN DISCHARGE (CFS) 28 28 28 28 29 28 28 30 29 26 25 27 26 25 25 25 24 25 26 23 22 21 20 20 19 20 20 22 e37 38 e26 MEAN CONCEN- TRATION (MG/L) MARCH 25 49 96 149 173 90 42 15 6 6 8 21 42 26 16 14 12 6 4 6 11 13 12 6 4 17 50 38 87 27 8 SEDIMENT DISCHARGE (TONS/DAY) 1.9 3.7 7.4 11 13 6.9 3.2 1.2 .49 .43 .53 1.5 3.0 1.8 1.1 .93 .76 .42 .25 .38 .64 .74 .69 .34 .23 .92 2.7 2.2 14 3.0 .55 798 85.90 e Estimated 82 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 DISCHARGE (CPS) e23 e23 e28 •25 •23 e22 e21 •20 e!9 e!9 e!9 e!8 e!8 e!7 e!7 e!7 e!5 e!5 e!4 e!4 e!4 elS e!4 13 12 11 11 11 11 11 —— CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL MEAN DISCHARGE (CPS) e23 e23 e28 •25 •23 e22 e21 •20 e!9 e!9 e!9 e!8 e!8 e!7 e!7 e!7 e!5 e!5 e!4 e!4 e!4 elS e!4 13 12 11 11 11 11 11 7 8 11 14 11 9 15 129 10 4 5 6 4 3 23 86 21 4 9 78 161 206 263 322 317 268 46 5 5 5 • .45 e.52 • .78 • .99 • .69 e.56 e.86 •7.1 e.52 e.18 e.25 e.30 e.17 e.15 •1.0 •4.0 e.94 e.18 e.34 e2.9 e6.1 e8.1 e9.8 11 9.9 8.3 1.4 .16 .14 .16 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY MEAN DISCHARGE (CPS) TOTAL 510 77.94 12 48 37 18 14 14 15 13 51 e43 •22 e!9 e!7 e!6 e!6 14 15 14 13 13 13 13 27 31 •36 45 135 93 29 20 37 903 9 166 40 20 12 7 10 17 108 208 44 19 16 151 15 16 9 5 5 6 4 4 23 13 12 54 253 77 4 4 39 —— .33 69 4.7 .96 .43 .26 .42 .59 60 e59 4.1 1.0 .78 6.8 .64 .63 .36 .20 .19 .20 .15 .14 4.3 1.4 e.95 18 248 36 .35 .21 13 533.09 CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 39 22 19 17 16 16 16 15 14 14 13 13 14 13 11 11 11 el4 22 25 14 13 11 11 11 11 19 20 20 18 38 13 12 12 11 18 15 11 7 4 4 4 3 2 4 7 8 10 21 22 18 18 16 15 13 11 17 11 185 328 4.5 .77 .61 .54 .45 .76 .63 .45 .26 .16 .15 .14 .10 .08 .12 .19 .24 e.41 1.6 1.6 .68 .61 .49 .45 .37 .33 .90 .65 14 15 483 47.24 e Estimated RXO ORANDE DE ARBCXBO BASXN 50026025 RXO CAONXLLAS AT PASO PALMA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 83 COMCEM- SEDIMENT DISCHARGE TRATXON DISCHARGE BAY (CFS) (MO/L) (TONS/DAY) CONCEN- SEDIMENT DISCHARGE TRATXON DISCHARGE (era) (m/D (tons/tact) MEAN CONCCN- SXDXMENT DISCHARGE TRATXON DISCHARGE (CFS) (MG/L) (TONS/DAY) JOLY AUGUST 7 8 9 10 11 12 13 14 15 1C 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 14 12 11 10 11 10 10 17 17 13 11 12 14 12 12 13 12 12 14 26 55 24 18 15 14 14 12 12 11 12 32 165 81 39 19 9 6 7 71 13 6 8 11 15 23 54 80 31 14 47 162 200 168 37 10 14 17 9 5 7 10 166 TOTAL 482 YEAR 18201 • E«tiMt«d 6.5 2.7 1.2 .54 .27 .15 .21 6.4 .62 .20 .23 .36 .57 .75 1.7 2.7 1.1 .44 1.9 12 29 11 1.8 .39 .55 .65 .28 .14 .19 .30 32 116.84 12129.30 30 15 15 21 15 13 12 121 •177 90 51 34 206 269 •162 73 54 42 34 30 36 36 45 76 39 31 38 67 57 34 27 1950 39 17 9 9 10 3.4 .73 .35 .51 .39 8 .28 7 .25 371 482 556 «340 267 75 30 29 685 941 328 98 45 22 11 6 19 40 61 106 30 18 34 83 53 14 11 4.5 3.0 672 1200 •175 20 6.7 2.5 1.0 .46 2.7 3.9 16 26 3.3 1.5 4.4 22 9.0 1.4 .78 3079.05 54 100 79 45 40 36 30 26 24 22 21 25 29 22 21 20 18 18 17 17 17 20 18 46 S3 27 24 26 47 55 997 84 139 93 34 25 27 15 13 12 8 6 10 15 6 4 6 8 4 4 4 4 5 6 210 366 19 12 25 66 58 39 44 22 4.3 2.9 2.6 1.2 .95 .78 .50 .34 .95 1.3 .32 .25 .33 .38 .21 .19 .18 .19 .24 .28 84 68 1.4 .86 1.8 12 10 301.45 84 RIO ORANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE OCT 1996 02... NOV 21... AU6 1997 13... SEP 03... DATE OCT 1996 02... NOV 21... AU6 1997 13... SEP 03... TIME 1705 1645 1315 1700 SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) 29 67 60 71 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 72 844 159 61 SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) 34 78 72 80 SEDI- MENT, SUS- PENPBP (MO/L) (80154) 7600 2860 3950 2230 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 44 94 87 96 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 1480 6520 1700 367 SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM (70332) 67 98 96 98 SSD* SUSP. FALL DIAM. * FINER THAN .002 MM (70326) 10 32 34 38 SRD« SUSP. SIEVE DIAM. * FINER THAN .250 MM (70333) 94 100 99 99 SED. SUSP. FALL DIAM. * FINER THAN .004 MM (70327) 15 39 34 47 SED. SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) 99 100 100 99 SED. SUSP. FALL DIAM. * FINER THAN .008 MM (70328) 21 49 46 60 SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 99 100 100 100 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALHA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 85 DATE OCT 1995 03... 24... 25... NOV 13... JAN 1996 14... 15... FEB 23... 23... APR 03... MAY 04... 21... 30... JUN 04... 19... 30... JUL 09... 31... AUG 01... OCT 02... JAN 1997 18... FEB 25... MAR 29... JUN 30... AUG 13... 28... SEP 03... TIME 1851 0935 1750 1730 2055 0415 1815 2330 1830 1610 1835 1600 0930 1800 1541 2100 1130 1625 1705 1400 1200 1825 1130 1315 1130 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 356 440 1130 255 327 281 2150 422 132 25 E250 E600 E220 606 E32 400 39 430 72 E42 33 75 14 159 45 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1650 570 224 255 3020 307 1740 5020 2570 5370 7300 2120 1570 976 1310 450 547 1290 7600 617 8 604 339 3950 3940 SEDI- SED. HENT, SUSP. DIS- SIEVE CHARGE, DIAM. SUS- % FINER FENDED THAN (T/DAY) .062 MM (80155) (70331) 1590 677 683 176 2670 233 10100 5720 916 362 E4930 E505 E848 1600 E113 486 38 1500 1480 E70 0.71 122 13 1700 479 78 97 93 87 93 88 92 94 98 46 82 80 69 95 65 97 55 92 44 63 93 84 97 87 76 1700 61 2230 367 96 86 RIO GRANDE DE ARBCIBO BASIN 50026050 RIO CAONILLAS ABOVE LAQO CAONILLAS NEAR JAYUYA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°13'26", long 66°38'22", 300 ft (91 m) off Highway 531, 700 ft (213 m) upstream from Lago Caonillas, 3.3 ml (5.3 km) northwest of Jayuya plaza. DRAINAOE AREA.--40.4 mi* (104.6 km*). PERIOD or RECORD.--Water year* 1979 to current year. WATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 19... FEB 1997 21... JUN 12... SEP 02... TIME 0900 0810 1225 1510 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) E191 38 16 64 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 147 240 283 186 PH MATER WHOLE FIELD (STAND- ARD UNITS) (00400) 6.6 6.7 8.2 7.1 TEMPER- ATURE WATER (DBG C) (00010) 20.5 20.5 31.5 27.0 TUR- BID- ITY (NTU) (00076) 37 0.70 1.6 60 OXYGEN, DIS- SOLVED (MG/L) (00300) 7.8 7.5 7.6 7.3 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 87 84 98 95 OXYGEN DEMAND, CHEMB ICAL (HIGH LEVEL) (MO/L) (00340) 11 <10 <10 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 4500 K940 K36 20000 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 28000 480 230 7000 DATE NOV 1996 19... FEB 1997 21... JUN 12... SEP 02... HARD- NESS TOTAL (MO/L AS CACO3) (00900) 57 — 110 65 CALCIUM DIS- SOLVED (MO/L AS CA) (00915) 15 — 29 17 MAGNE- SIUM, DIS- SOLVED (MO/L AS MO) (00925) 4.7 — 8.4 5.3 SODIUM, DIS- SOLVED (MO/L AS NA) (00930) 8.5 — 15 9.7 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 0.6 0.5 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 — 2.1 2.6 ALKA- LINITY MAT WH TOT FET FIELD MG/L AS CAC03 (00410) 58 84 95 61 SULFIDE TOTAL (MO/L AS S) (00745) <0.5 — <0.5 — SULFATE DIS- SOLVED (MO/L AS 804) (00945) 12 — 20 12 CHLO- RIDE, DIS- SOLVED (MO/L AS CD (00940) 8.5 — 16 10 DATE NOV 1996 19... FEB 1997 21... JUN 12... SEP 02... FLUO- RIDE, DIS- SOLVED (MO/L AS F) (00950) <0.10 — 0.12 <0.10 SILICA, DIS- SOLVED (MO/L AS SI02) (00955) 20 — 24 20 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MO/L) (70301) 105 — 172 114 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) E54 — 7.22 19.8 RESIDUE TOTAL AT 105 DBG. C, SUS- PENDED (MG/L) (00530) 62 2 <1 60 NITRO- GEN, NITRATE TOTAL (MO/L AS N) (00620) 1.30 1.10 0.030 0.580 NITRO- QEN* NITRITE TOTAL (MO/L AS N) (00615) 0.020 <0.010 <0.010 <0.010 NITRO- NITRO- NITRO- GEN, GEN, GEN, NO2+NO3 AMMONIA ORGANIC TOTAL TOTAL TOTAL (MO/L (MG/L (MG/L AS N) AS N) AS N) (00630) (00610) (00605) 1.30 0.030 0.29 1.10 0.020 0.27 0.030 0.030 <0.20 0.590 0.030 0.52 DATE NITRO- GEN, AM- MONIA 4- NITRO- NITRO- ORGANIC GEN, GEN, TOTAL TOTAL TOTAL (MO/L (MO/L (MO/L AS N) AS N) AS N03) (00625) (00600) (71887) X • non-ideal count E - estimated PHOS- PHORUS TOTAL (MO/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM MATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) NOV 1996 19... FEB 1997 21... JUN 12... SEP 02... 0.32 0.30 <0.23 0.55 1.6 1.4 0.22 1.1 7.1 6.0 0.95 5.0 0.100 0.050 0.040 0.120 <100 <100 20 30 10 RIO ORANDE DE ARECZBO BASIN 87 50026050 RIO CAONXLLAS ABOVE LAGO CAONILLAS NEAR JAYUYA, PR—Continued HATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) NOV 1996 19... FEE 1997 21... JUN 12... SEP 02... 2300 60 130 <0.10 22 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 88 RIO GRANDE DE ARECIBO BASIN 50026140 LAGO CAONILLAS AT DAMSITE NEAR UTUADO, PR LOCATION.—Lat 18°16'43", long 66°39'24", Hydrologic Unit 21010001, at Lago Caonlllas Dam on Rio Caonillas, 2.9 mi (4.7 km) northeast of Plaza de Utuado, 0.3 mi (0.6 km) west from Iglesia Santa Maria del Monte Carmelo, and 1.8 mi (3.0 km) northwest from Hacienda Carbonell. DRAINAGE AREA.—48.4 mi 1 (125.4 km 1 ). ELEVATION RECORDS PERIOD OF RECORD.—March 1991 to current year. Prior to October 1994, published as Lago Caonillas at Caonillas. GAGE.—water stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Caonillas was completed in 1948. The dam is a concrete gravity structure with a total length of 815 ft (248 m), a maximum height of 235 ft (72 m), and a maximum base width of 195 ft (59 m). Non-overflow sections on each abutment have a total length of 603 ft (184 m). The dam is the main unit of Caonillas Hydroelectric Project, and provides 49,000 acre-feet (60 hm3 ) of usable storage for power generation at Caonillas Power Plant No. 1 located 2.5 mi (4.0 km) downstream from the dam. The dam is owned by Puerto Rico Electric Power Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.—Maximum elevation, 829.37 ft (252.79 m), Sept. 11, 1996; minimun elevation, 737.92 ft (224.92 m), Aug. 8, 1997. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximum elevation, 827.63 ft (252.26 m), Jan. 27; minimum elevation, 737.92 ft (224.92 m), Aug. 8. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 705 750 Contents, in acre-feet 0 8,421 Elevation, in feet 800 830 Contents, in acre-feet 27,982 46,161 MAX MIN ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT NOV JAN FEB MAR APR JUN AUG 807.89 804.77 823.80 812.89 826.68 824.13 827.59 823.39 826.04 813.84 813.90 796.01 794.81 767.86 766.09 745.19 746.44 739.35 739.71 738.04 761.05 739.41 CAL YR 1996 WTR YR 1997 MAX 828.47 MAX 827.59 MIN 773.30 MIN 738.04 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 805.98 804.77 805.09 805.36 805.44 805.53 805.35 805.53 805.70 805.84 805.99 806.13 806.26 806.40 806.37 806.52 807.17 807.42 807.67 807.89 A A A A A A A A A A A A 812.89 813.06 813.20 813.33 813.44 813.63 813.74 813.88 814.17 814.50 814.81 814.19 814.25 814.41 814.66 816.14 817.38 818.08 818.51 819.70 820.71 820.90 821.43 821.93 822.36 822.72 823.09 823.36 823.80 —— 824.13 824.28 824.55 824.81 824.97 825.18 825.27 825.26 824.90 824.87 825.37 825.88 826.22 826.51 826.68 826.05 826.03 826.17 826.17 826.23 826.32 826.48 826.33 826.23 826.27 825.73 825.80 825.89 826.00 825.43 825.30 825.38 825.51 825.84 825.92 826.07 826.19 825.81 825.60 825.70 825.49 825.21 825.15 825.04 824.31 823.72 823.39 823.48 823.46 823.69 823.90 825.61 827.04 827.21 827.31 827.43 827.59 826.96 826.72 825.90 825.83 825.88 826.04 825.96 825.86 825.40 824.57 823.92 823.85 823.81 823.91 823.62 822.76 821.89 821.17 820.53 820.57 819.77 819.44 819.25 818.65 817.91 817.07 817.14 817.03 816.59 816.08 815.09 814.74 813.84 —— —— 813.90 813.81 813.03 812.35 811.78 811.06 810.30 810.33 810.33 809.74 808.99 808.55 807.70 806.74 806.24 805.86 804.88 804.49 803.75 802.69 801.95 801.67 801.19 800.36 799.20 798.07 797.36 796.98 796.96 796.36 796.01 794.81 794.78 A A A A A A A A A A A A A A A A A A A A 777.31 775.90 774.64 772.71 772.48 771.37 769.78 767.86 —— 766.09 764.70 764.73 764.71 763.63 762.35 761.03 760.96 761.47 759.57 759.13 756.67 756.12 754.00 751.87 751.44 750.75 747.48 745.82 745.94 746.06 745.19 745.30 745.41 745.47 745.60 745.64 745.88 745.87 745.86 746.25 746.44 745.99 743.38 743.10 743.09 742.99 742.12 741.76 741.71 741.63 741.52 741.39 741.28 741.14 741.01 740.85 740.38 740.28 740.25 740.29 740.04 739.89 739.79 739.67 739.47 739.35 739.39 739.38 739.79 740.06 —— 739.71 739.62 739.51 739.34 739.17 739.07 738.94 738.88 738.81 738.71 738.59 738.46 738.37 738.26 738.11 738.09 738.04 738.11 738.14 738.30 738.76 738.84 738.80 738.79 738.73 738.72 738.67 738.62 A A A 739.62 739.58 739.59 739.65 739.58 739.51 739.41 740.87 743.44 744.46 744.84 745.10 748.60 754.54 756.57 757.22 757.66 757.89 758.07 758.20 758.52 758.75 758.82 759.47 759.65 759.74 759.86 760.21 760.54 760.74 761.05 761.05 761.69 762.10 762.27 762.39 762.48 762.52 762.63 762.78 762.86 762.86 762.86 762.90 762.89 762.88 762.86 762.83 762.80 762.80 762.79 762.81 762.82 762.84 763.01 763.24 763.31 763.37 763.42 762.53 762.82 —— 763.42 761.05 A No gage-height record RIO GRANDE DE ARECIBO BASIN 50027250 RIO GRANDE DE ARECIBO BELOW LAGO DOS BOCAS NEAR FLORIDA, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°20'50", long 66«40'02", at pedestrian bridge, 0.7 mi (1.1 km) downstream from Lago and 6.6 mi (10.6 km) west of Florida plaza. DRAINAGE AREA.—169 mi* (436 kma ) does not include 6.0 mi* (15.6 kma ) above Lago Garzas. PERIOD OF RECORD.—Water years 1970-71, 1974 to current year. 89 Dos Bocas WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DBG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 30... 1200 E1500 198 6.8 25.5 95 5.8 69 <10 K830 4800 FEB 1997 13... 0845 22 226 6.6 22.5 4.0 5.4 61 <10 K10 K500 JUN 10... 0820 17 233 7.3 27.0 1.5 4.1 51 <10 K150 K40 SEP 03... 1215 E1500 222 6.8 27.5 180 4.5 57 <10 2600 3900 ALKA- DATE OCT 1996 30... FEB 1997 13... JUN 10... SEP 03... DATE OCT 1996 30... FEB 1997 13... JUN 10... SEP 03... DATE OCT 1996 30... FEB 1997 13... JUN 10... SEP 03... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 77 — 88 81 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.42 0.20 0.42 0.64 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 22 — 24 23 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 21 — 20 18 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.5 1.2 0.59 1.2 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.3 — 7.0 5.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 124 — 137 126 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 6.6 5.1 2.6 5.5 SODIUM, BIS- SOLVED (MG/L AS NA) (00930) 9.2 — 10 9.7 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) E 502 — 6.46 E 510 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.020 0.120 0.240 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 0.5 0.5 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 90 5 2 108 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.7 — 2.3 2.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.00 0.960 0.140 0.560 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 ~ LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 70 80 80 73 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.050 <0.010 0.030 0.050 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — <10 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 ~ — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.10 0.960 0.170 0.610 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 13 — 14 13 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.060 0.010 0.160 0.070 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 2 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 8.8 — 12 10 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.37 <0.20 0.25 0.57 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) ^10 — ^10 — E- estimated K » non-ideal count 90 RIO GRANDE DE ARECIBO BASIN 50027250 RIO GRANDE DE ARECIBO BELOW LAGO DOS BOCAS NEAR FLORIDA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 30... FEB 1997 13... JUN 10... SEP 03... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) 01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS HN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 2700 80 <1 150 88 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 <0.01 0.01 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR 91 LOCATION.--Lat 18°25'22", long 66°41'58" f Hydrologic Unit 21010002, 0.5 mi (0.8 km) upstream from Rio Tanama, 3.6 mi (5.8 km) south of Arecibo and 4.9 mi (7.9 km) above mouth, and 6.2 mi (9.97 km) downstream from Lago Dos Bocas. DRAINAGE AREA.—174 mi a (451 km 2 ), approximately, of which an undetermined amount does not contribute directly to surface runoff. PERIOD OF RECORD.--April 1982 to current year. GAGE.--Water-stage recorder. Elevation of gage is 30 ft (9 m), from topographic map. REMARKS.--Records fair. Flow regulated by Lago Dos Bocas Dam 10.4 mi (16.7 km) upstream from gage. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV JAN FEB MAR APR JUL AUG SEP 1 582 554 2 631 164 3 666 143 4 592 315 5 548 160 6 294 291 7 425 497 8 152 389 9 115 223 10 87 268 11 64 376 12 58 319 13 99 454 14 136 343 15 401 194 16 561 307 17 374 210 18 480 730 19 174 926 20 153 873 21 526 448 22 512 518 23 596 594 24 473 282 25 478 464 26 169 431 27 209 420 28 87 194 29 122 319 30 534 224 31 566 TOTAL 10864 11630 MEAN 350 388 MAX 666 926 MIN 58 143 AC-FT 21550 23070 CFSM 1.75 1.94 IN. 2.02 2.16 STATISTICS OF MONTHLY MEAN MEAN 600 525 MAX 1984 1413 (WY) 1986 1986 MIN 171 123 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 468 527 363 205 431 406 559 292 483 505 434 207 116 371 376 498 314 227 197 187 203 206 273 264 159 440 427 181 143 431 233 10126 327 559 116 20080 1.63 1.88 DATA 286 570 1988 72.4 1995 140 158 162 377 203 200 151 234 122 85 311 131 215 463 419 334 308 231 249 278 673 2730 1040 713 669 496 558 439 447 439 432 13407 432 2730 85 26590 2.16 2.49 FOR WATER 249 437 1988 83.5 1995 199 230 265 331 378 363 250 198 183 390 386 406 358 329 177 296 237 214 252 314 372 296 188 274 245 360 367 326 ___ ___ --- 8184 292 406 177 16230 1.46 1.52 YEARS 1982 229 428 1988 61.3 1995 136 91 296 313 263 293 371 166 86 275 346 281 314 335 245 312 328 259 297 256 201 94 233 268 286 327 343 183 153 204 257 7812 252 371 86 15500 1.26 1.45 - 1997 217 351 1985 91.2 1994 FOR 1996 CALENDAR YEAR 129056 353 12300 30 60 256000 1. 24. 560 223 77 Sep 10 Jul 31 Jul 25 76 00 255 249 140 278 221 141 67 230 286 336 340 142 75 63 208 351 340 360 148 97 132 135 327 315 168 68 363 241 216 285 —— 6577 219 363 63 13050 1.10 1.22 287 303 200 135 155 200 226 218 109 314 198 258 336 213 310 245 103 263 313 141 90 80 134 166 181 269 270 73 133 130 62 6115 197 336 62 12130 .99 1.14 37 35 102 282 312 281 178 70 135 51 176 75 39 34 30 45 77 61 34 31 29 56 162 66 38 35 31 31 33 37 2603 86.8 312 29 5160 .43 .48 202 274 187 70 41 37 36 78 72 37 83 56 37 34 119 73 58 103 101 85 128 136 118 189 107 43 37 176 302 267 257 3543 114 302 34 7030 .57 .66 221 113 110 41 37 65 75 93 70 70 68 134 166 317 587 273 243 231 162 294 137 276 251 151 270 264 294 300 149 102 63 5627 182 587 37 11160 .91 1.05 81 299 418 358 241 240 101 259 328 224 224 109 64 48 52 132 93 85 91 47 85 43 38 65 48 39 54 108 361 326 --- 4661 155 418 38 9250 .78 .87 , BY WATER YEAR (WY) 343 617 1986 65.7 1995 FOR 1997 91149 250 2730 29 39 4280 10 180800 1 16 463 224 57 566 2000 1986 178 1994 WATER YEAR Jan 22 Jun 21 Jun 24 Jan 22 .47 Jan 22 .25 .95 339 683 1987 69.3 1994 245 374 1987 62.7 1994 WATER 362 729 132 14800 16 22 45800 18 262100 1 24 742 237 55 246 474 1988 82.8 1994 YEARS 1982 - May 18 Apr 14 Mar 30 May 18 .22 May 18 .81 .58 506 1479 1996 99.9 1994 1997 1986 1994 1985 1994 1994 1985 1985 - RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE IKE ARECIBO ABOVE ARECIBO, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water year 1982 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October, 1995 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1995. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 1,540 mg/L September 10, 1996; Minimum daily mean, 2 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 53,700 tons (48,700 tonnes) September 10, 1996; Minimum daily mean, 0.18 ton (0.16 tonne) June 15, 1997. EXTREMES FOR CURRENT YEAR 1997. SEDIMENT CONCENTRATION: Maximum daily mean, 141 mg/L January 22, 1997; Minimum daily mean, 2 mg/L June 14-15, 1997. SEDIMENT LOADS: Maximum daily mean, 1,060 tons (961 tonnes) January 22, 1997; Minimum daily mean, 0.18 ton (0.16 tonne) June 15, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 582 631 666 592 548 294 425 152 115 87 64 58 99 136 401 561 374 480 174 153 526 512 596 473 478 169 209 87 122 534 566 61 45 51 47 27 25 38 16 12 9 6 6 11 15 43 58 26 48 20 58 30 75 38 53 50 17 22 8 23 73 66 129 91 113 95 43 24 59 8.5 4.4 2.3 1.1 .88 7.9 8.5 69 122 38 79 18 27 77 129 76 97 105 11 17 2.5 16 124 143 554 164 143 315 160 291 497 389 223 268 376 319 454 343 194 307 210 730 926 873 448 518 594 282 464 431 420 194 319 224 ___ MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) NOVEMBER 554 164 143 315 160 291 497 389 223 268 376 319 454 343 194 307 210 730 926 873 448 518 594 282 464 431 420 194 319 224 49 16 14 31 17 24 51 37 24 30 38 32 45 35 41 32 44 113 116 139 42 53 56 29 68 43 39 31 36 23 94 8.1 7.3 38 13 35 100 56 23 36 49 38 67 41 27 35 33 273 292 346 66 100 111 35 98 66 59 19 46 21 MEAN DISCHARGE (CFS) 468 527 363 205 431 406 559 292 483 505 434 207 116 371 376 498 314 227 197 187 203 206 273 264 159 440 427 181 143 431 233 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 52 52 36 21 45 46 60 29 51 53 41 23 11 40 39 53 37 27 21 30 22 22 31 28 16 50 45 20 15 40 47 91 98 46 13 90 63 122 35 96 96 63 18 3.6 71 57 105 39 23 14 19 17 19 28 27 9.4 87 75 11 7.4 65 37 10864 1738.08 11630 2232.4 10126 1545.4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JANUARY 93 140 158 162 377 203 200 151 234 122 85 311 131 215 463 419 334 308 231 249 278 673 2730 1040 713 669 496 558 439 447 439 432 14 21 16 38 20 22 16 23 23 19 33 13 21 44 43 37 33 24 27 29 50 141 116 116 84 52 68 55 50 49 48 7. 12 9. 52 19 17 10 22 7. 5. 36 5. 15 82 56 41 34 17 22 25 131 1060 324 229 154 74 107 79 75 72 70 5 5 9 2 6 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) FEBRUARY 199 230 265 331 378 363 250 198 183 390 386 406 358 329 177 296 237 214 252 314 372 296 188 274 245 360 367 326 —— 22 24 29 33 40 41 26 20 21 45 43 45 32 33 19 33 25 20 27 35 42 32 19 29 23 36 38 33 ___ ___ 17 19 26 36 54 53 21 12 19 61 56 63 38 38 13 40 20 13 29 40 56 35 14 30 21 49 47 38 MARCH 136 91 296 313 263 293 371 166 86 275 346 281 314 335 245 312 328 259 297 256 201 94 233 268 286 327 343 183 153 204 257 15 9 20 24 25 33 40 17 8 17 29 29 30 37 28 34 24 28 28 26 16 6 25 24 26 28 29 24 19 21 32 6 2 20 26 24 42 53 10 1 21 34 28 32 42 23 41 28 24 28 22 13 1 19 24 26 32 34 14 9 14 25 .1 .1 .9 .8 .1 13407 2870.7 8184 958 7812 720.0 94 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 255 249 140 278 221 141 67 230 286 336 340 142 75 63 208 351 340 360 148 97 132 135 327 315 168 68 363 241 216 285 —— APRIL 21 25 14 23 19 15 7 19 26 27 28 16 9 7 49 26 35 41 16 10 13 23 27 28 18 7 23 24 19 24 —— MAY 22 21 6 24 16 8 1 21 26 32 32 6 1 1 29 22 43 54 11 3 11 13 31 30 8 1 30 21 17 24 - .7 .1 .3 .5 .9 .2 .5 .8 .5 -- 287 303 200 135 155 200 226 218 109 314 198 258 336 213 310 245 103 263 313 141 90 80 134 166 181 269 270 73 133 130 62 27 28 22 15 14 16 21 23 15 27 19 30 31 22 23 24 11 31 29 14 6 4 13 17 16 23 22 9 14 11 7 28 28 19 9.0 12 16 20 18 4.8 33 12 24 33 16 25 18 3.0 38 31 5.6 1.5 .87 5.4 11 9.3 18 23 1.8 10 5.3 1.3 37 35 102 282 312 281 178 70 135 51 176 75 39 34 30 45 77 61 34 31 29 56 162 66 38 35 31 31 33 37 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 5 4 8 46 34 47 17 7 36 5 14 7 3 2 2 4 7 6 4 3 3 6 29 28 26 61 67 64 61 58 .48 .34 2.5 44 43 40 11 1.6 13 .78 15 2.0 .29 .23 .18 .56 2.7 1.2 .34 .28 .25 .97 18 6.0 2.5 5.7 5.6 5.3 5.4 5.7 TOTAL 6577 569.5 6115 480.87 2603 234.90 RIO GRANDE DE ARECIBO BASIN 95 50027750 RIO GRANDE DE ARECIBO ABOVE ARECZBO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 202 274 187 70 41 37 36 78 72 37 83 56 37 34 119 73 58 103 101 85 128 136 118 189 107 43 37 176 302 267 257 3543 91149 JULY 56 17 17 8 6 5 4 7 13 7 7 14 13 11 13 16 7 9 10 9 13 15 8 16 11 4 4 14 25 23 23 —— AUGUST 35 15 15 1.6 .69 .50 .38 3.7 2.6 .65 3.2 2.2 1.3 1.0 5.2 3.1 1.1 3.2 3.7 2.5 8.6 8.9 3.5 10 4.2 .52 .37 17 28 24 23 229.71 12639.52 221 113 110 41 37 65 75 93 70 70 68 134 166 317 587 273 243 231 162 294 137 276 251 151 270 264 294 300 149 102 63 5627 22 11 11 4 3 6 7 9 7 8 8 11 12 27 71 25 25 21 16 31 15 19 25 16 23 30 30 25 14 10 9 —— 18 3.9 4.5 .49 .34 1.4 1.8 2.7 1.4 1.6 1.7 6.3 8.7 31 115 28 24 20 8.8 41 8.6 25 21 12 25 36 32 28 8.9 6.0 1.8 524.93 SEPTEMBER 81 299 418 358 241 240 101 259 328 224 224 109 64 48 52 132 93 85 91 47 85 43 38 65 48 39 54 108 361 326 4661 8 27 93 39 27 21 11 23 35 24 28 11 7 5 5 19 24 12 10 5 18 18 16 14 5 4 5 11 30 28 —— 6.0 35 148 56 32 21 6.8 22 38 20 21 3.6 1.2 .66 .79 9.3 6.8 3.0 2.8 .65 4.2 2.0 1.7 2.3 .69 .44 1.2 5.9 47 35—— 535.03 96 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE OCT 1996 21... TIME 1915 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DIAM. H FINER THAN .002 MM (70326) SED. SUSP. FALL DXAM. * FINER THAN .004 MM (70327) SED. SUSP. FALL DXAM. * FINER THAN .008 MM (70328) 1230 1970 6550 37 43 53 DATE OCT 1996 21... SED. SUSP. FALL DIAM. H FINER THAN .016 MM (70329) SED. SUSP. FALL DXAM. * FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) SED. SUSP. SIEVE DXAM. * FINER THAN .125 MM (70332) SBD. SUSP. SIEVE DIAM. * FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 67 68 79 91 99 99 100 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR--Continued MATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT TIME 97 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) OCT 1996 21... 22... 23... 24... NOV 18... 19... 19... JAN 1997 14... 21... 21... 22... 22... MAR 13... 2355 1815 2315 0215 2244 0129 2139 2055 1840 2355 0240 0755 1235 1390 500 1010 1000 1030 1050 1080 1110 1290 1740 2190 3320 112 84 196 129 134 344 134 156 55 91 107 100 161 115 315 265 352 362 957 380 454 165 317 503 590 1440 35 88 100 85 94 86 96 93 93 95 87 96 87 66 98 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR LOCATION.--Lat 18°18'02", long 66°46'58", Hydrologic Unit 21010001, on downstream side of left abutment of bridge on Highway 111, 1.2 mi (1.9 km) upstream from natural tunnel, 1.5 mi (2.4 km) northeast of Angeles, and 5.8 mi (9.3 km) northwest of Utuado. DRAINAGE AREA.—18.4 mi 2 (47.7 km2 ). MATER-DISCHARGE RECORDS PERIOD OF RECORD.—June 1944 to June 1958 (daily stage and two to four measurements per month by Puerto Rico Water Resources Authority), November 1959 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 938.32 ft (286.000 m) above mean sea level. Datum of gage was lowered 3.00 ft (0.914 m) on Oct. 1978. Prior to Nov. 17, 1966, non-recording gage and Nov. 17, 1966 to Sept. 30, 1978 recording gage, both at present site. REMARKS.—Records fair except those for estimated daily discharges, which are poor. DISCHARGE, CUBIC FEET PER SECOND, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT JAN FEB MAR AUG SEP 1 76 100 2 68 90 3 74 85 4 64 81 5 62 79 6 88 78 7 68 75 8 66 76 9 62 77 10 59 135 11 57 85 12 61 113 13 175 85 14 133 73 15 e77 70 16 e97 83 17 206 109 18 e85 134 19 104 95 20 96 89 21 461 91 22 136 92 23 111 94 24 100 82 25 92 84 26 116 75 27 104 72 28 139 74 29 102 74 30 93 84 31 128 TOTAL 3360 2634 MEAN 108 87.8 MAX 461 135 MIN 57 70 AC-FT 6660 5220 CFSM 5.89 4.77 IN. 6.79 5.33 STATISTICS OF MONTHLY MEAN MEAN 80.1 67.9 MAX 195 159 (WY) 1990 1969 MIN 25.4 25.1 (WY) 1963 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 71 66 63 61 57 54 52 50 47 72 139 58 52 50 49 48 47 46 45 44 45 48 44 45 44 e44 e43 e43 e42 e41 e40 1650 53.2 139 40 3270 2.89 3.34 DATA 42.5 121 1966 21.5 1965 FOR 40 59 102 57 46 43 42 43 40 38 37 39 68 94 47 42 41 40 64 91 209 251 104 105 82 e71 e67 e63 e60 e58 e57 2200 71.0 251 37 4360 3.86 4.45 59 62 61 54 52 52 54 51 52 49 49 48 47 45 44 43 43 42 42 41 42 39 37 37 36 35 34 33 —— —— —— 1283 45.8 62 33 2540 2.49 2.59 FOR WATER YEARS 1960 30.0 71.0 1997 18.0 1974 26.1 50.8 1996 13.3 1965 33 32 32 33 32 30 30 30 29 28 27 27 28 29 31 32 35 35 42 37 29 29 28 27 28 28 27 47 40 47 39 1001 32.3 47 27 1990 1.75 2.02 - 1997 24.9 71.2 1972 11.0 1984 1996 CALENDAR YEAR 20699 56. 1390 15 17 41060 3. 41. 103 37 21 6 Sep 10 Jul 21 Jul 17 07 85 30 30 29 28 27 26 25 25 25 25 24 24 23 20 22 21 21 19 19 22 22 46 22 25 21 20 19 18 17 17 —— 712 23.7 46 17 1410 1.29 1.44 , BY MATER 36.0 143 1969 9.70 1984 16 46 27 19 18 18 17 17 18 18 17 17 16 16 15 16 15 16 15 14 15 21 33 56 61 58 37 25 20 29 55 781 25.2 61 14 1550 1.37 1.58 YEAR (WY) 56.8 193 1963 12.4 1977 39 22 20 17 16 16 15 15 14 14 16 16 16 15 15 14 15 17 19 51 23 19 19 15 15 34 27 19 18 28 —— 599 20.0 51 14 1190 1.09 1.21 42.0 116 1979 15.6 1994 FOR 1997 MATER YEAR 17277 47.3 461 14 15 7420 15.76 14 34270 2.57 34.93 91 37 16 Oct 21 May 20 May 15 Oct 21 Oct 21 May 20 21 17 17 16 16 16 16 29 24 16 15 17 17 15 64 24 18 18 18 17 26 18 16 16 18 23 17 16 28 20 18 627 20.2 64 15 1240 1.10 1.27 35.6 65.7 1981 9.18 1994 17 16 17 21 17 16 16 46 55 78 48 30 39 58 43 53 32 29 28 34 38 27 112 63 38 30 28 26 44 142 e78 1319 42.5 142 16 2620 2.31 2.67 45.5 110 1979 15.9 1994 WATER YEARS 1960 - 46.9 71.1 20.7 2170 5.4 6.4 12200 17.45 5.4 33950 2.55 34.61 83 33 16 May 17 Aug 4 Jul 29 May 18 May 18 Aug 4 e34 e!25 e44 e36 32 29 28 27 25 24 23 34 26 51 35 25 22 21 21 19 22 25 22 51 31 22 80 36 93 48 —— 1111 37.0 125 19 2200 2.01 2.25 74.3 177 1961 25.0 1994 1997 1969 1994 1963 1994 1994 1985 1985 1994 e Estimated 99 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Watar yaara 1958 to currant yaar. PERIOD OF DAILY RECORD.— SUSPENDED SEDINENT DISCHARGE: January 1968 to currant yaar. INSTRUMENTATION.--USD-49 •adinant sampler since Octobar 1968. Automatic sediment sampler since 1990. REMARKS.—Sedimant samples wara collacted by a local observer on a weakly basis. During high flow events sediment samples wara collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATIONS: Maximum daily mean, 20,400 mg/L November 27, 1968; minimum daily mean, <1 mg/L during water year 1985. SEDIMENT LOADS: Maximum daily, 167,000 tons (152,000 tonnes) May 18, 1985, minimum daily, <0.01 ton (<0.01 tonne) several days during many years. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATIONS: Maximum daily mean, 2,010 mg/L Octobar 21, 1996; minimum daily mean, 3.0 mg/L April 16, 1997. SEDIMENT LOADS: Maximum daily, 14,500 tons (13,200 tonnes) Octobar 21, 1996; minimum daily, 0.20 ton (0.18 tonne) April 16, 1997. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 3.997 DATE OCT 1996 31... FEB 1997 12... MAY 20... AUO 27... TIME 0855 0830 1115 1255 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 86 49 13 27 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 155 168 169 178 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 6.5 6.4 8.3 7.7 TEMPER- ATURE WATER (DEO C) (00010) 21.5 19.0 24.5 27.0 TUR- BID- ITY (NTU) (00076) 4.9 1.6 1.2 5.6 OXYGEN, DIS- SOLVED (MO/L) (00300) 8.1 8.4 7.9 7.5 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00303.) 92 93. 98 97 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) <10 <10 10 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (33.616) 400 230 K30 K3.80 STREP- TOCOCCI FECAL, (COLS. PER 3.00 ML) (31679) 720 640 X160 230 DATE OCT 1996 31... FEB 1997 12... MAY 20... AUG 27... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 56 .. 69 66 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 14 .. 18 17 MAGNE- SIUM, DIS- SOLVED (MG/L AS MO) (00925) 5.2 — 5.9 5.4 SODIUM, DIS- SOLVED (MG/L AS MA) (00930) 7.4 .. 9.2 8.3 SODIUM AD- SORP- TION RATIO (00931) 0.4 .. 0.5 0.4 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 .. 1.7 2.1 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 46 59 56 59 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — 0.5 — 8ULFATE DIS- SOLVED (MG/L AS 804) (00945) 11 — 13 11 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 8.6 — 9.0 7.6 non-ideal count 100 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR--Continued WATER-QUALITY DATA, WATER YEARS OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 31... FEB 1997 12... MAY 20... AUG 27... OCT 1996 31... FEB 1997 12... HAY 20... AUG 27... DATE FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — <0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 <0.20 <0.20 <0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 25 — 26 25 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.3 1.1 0.61 1.0 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 101 -- 115 112 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 5.6 4.8 2.7 4.5 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 23.3 -- 4.15 8.18 PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 <0.020 <0.020 0.080 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 11 3 <1 9 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 0.980 0.550 0.830 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 10 — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.10 0.980 0.560 0.840 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 <0.010 0.020 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 31... FEB 1997 12... MAY 20... AUG 27... 420 340 <1 <1 30 20 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <0.01 <0.01 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 101 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 76 68 74 64 62 88 68 66 62 59 57 61 175 133 e77 a97 206 e85 104 96 461 136 111 100 92 116 104 139 102 93 128 MEAN CONCEN- TRATION (MG/L) OCTOBER 51 30 50 32 19 248 45 42 30 20 15 20 625 297 52 56 845 114 54 28 2010 593 88 40 37 267 198 457 79 27 331 SEDIMENT DISCHARGE (TONS /DAY) 11 5.6 13 5.6 3.2 133 8.3 7.6 5.0 3.2 2.2 4.0 1420 219 all a!4 2500 a26 15 7.4 14500 247 27 11 9.0 161 61 355 22 6.8 218 MEAN DISCHARGE (CFS) 100 90 85 81 79 78 75 76 77 135 85 113 85 73 70 83 109 134 95 89 91 92 94 82 84 75 72 74 74 84 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) NOVEMBER MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 100 90 85 81 79 78 75 76 77 135 85 113 85 73 70 83 109 134 95 89 91 92 94 82 84 75 72 74 74 84 89 60 34 18 11 10 10 15 52 426 117 334 66 21 18 109 286 431 109 31 56 81 78 50 41 15 12 11 10 52 24 15 7.7 3.9 2.3 2.1 2.0 3.4 11 335 27 200 16 4.1 3.5 37 179 277 29 7.6 14 23 20 11 9.5 3.0 2.4 2.2 2.0 15 71 66 63 61 57 54 52 50 47 72 139 58 52 50 49 48 47 46 45 44 45 48 44 45 44 a44 a43 a43 e42 a41 a40 33 14 7 6 7 7 7 8 9 160 702 22 13 11 9 8 8 8 11 15 20 15 11 8 6 5 4 6 8 10 10 6.4 2.6 1.2 1.0 1.0 1.0 1.0 1.0 1.1 45 363 3.5 1.9 1.5 1.2 1.1 .95 .94 1.3 1.8 2.4 1.9 1.3 .96 .74 a. 59 a. 50 a. 65 a. 88 al.l al.l TOTAL 3360 20031.9 2634 1288.7 1650 450.61 a Estimated 102 RIO GRANDE DE ARECIBO BASIN 50028000 RZO TANAMA NEAR UTUADO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 40 59 102 57 46 43 42 43 40 38 37 39 68 94 47 42 41 40 64 91 209 251 104 105 82 e71 e67 e63 e60 e58 e57 11 116 320 57 48 32 20 18 26 23 20 23 294 160 28 18 15 17 168 207 1650 1870 63 134 33 13 9 8 6 7 8 1.1 46 214 8.8 6.0 3.6 2.3 2.2 2.8 2.4 2.0 2.4 176 79 3.6 2.0 1.6 1.8 120 87 1330 1810 18 45 7.3 e2.4 el. 7 el. 3 el.O el.l el. 3 2200 3983.7 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 59 62 61 54 52 52 54 51 52 49 49 48 47 45 44 43 43 42 42 41 42 39 37 37 36 35 34 33 1283 10 21 38 23 28 37 44 32 34 25 15 9 6 5 5 5 7 10 13 8 4 5 7 8 7 7 6 6 1.6 4.0 6.4 3.4 3.9 5.2 6.4 4.4 4.9 3.3 2.0 1.2 .72 .61 .60 .62 .83 1.1 1.4 .85 .50 .55 .66 .77 .70 .62 .56 .50 MEAN DISCHARGE (CFS) 33 32 32 33 32 30 30 30 29 28 27 27 28 29 31 32 35 35 42 37 29 29 28 27 28 28 27 47 40 47 39 MEAN CONCEN- TRATION (MG/L) MARCH 5 5 8 13 17 12 7 5 7 10 12 10 9 7 6 6 10 20 26 39 16 12 10 11 12 13 14 52 29 64 27 SEDIMENT DISCHARGE (TONS/DAY) .47 .48 .71 1.1 1.5 .96 .61 .45 .56 .74 .89 .76 .65 .56 .52 .48 1.1 1.9 3.6 4.1 1.3 .96 .78 .81 .89 .96 1.0 11 3.5 18 3.1 58.29 1001 64.44 e Estimated RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTOADO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 103 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) 30 30 29 28 27 26 25 25 25 25 24 24 23 23 22 22 21 20 19 19 22 46 29 22 21 21 20 19 18 17 APRIL 19 15 12 10 12 13 15 13 12 11 11 12 11 7 5 3 5 7 10 11 13 200 18 14 11 9 6 5 5 6 1.5 1.2 .95 .78 .83 .92 .99 .90 .82 .74 .74 .75 .69 .45 .28 .20 .25 .37 .52 .56 .84 75 1.5 .83 .66 .49 .35 .26 .26 .26 16 46 27 19 18 18 17 17 18 18 17 17 16 16 15 16 15 16 15 14 15 21 33 56 61 58 37 25 20 29 55 CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 16 46 27 19 18 18 17 17 18 18 17 17 16 16 15 16 15 16 15 14 15 21 33 56 61 58 37 25 20 29 55 6 137 115 76 48 30 21 26 36 45 41 35 30 24 19 16 18 21 25 29 33 32 36 270 193 260 27 27 13 36 235 .25 78 8.6 3.9 2.4 1.5 .97 1.2 1.7 2.1 1.9 1.6 1.3 1.0 .78 .69 .71 .90 1.1 1.1 1.4 1.7 6.4 124 117 93 2.9 1.9 .70 5.1 109 MEAN DISCHARGE (CFS) 39 22 20 17 16 16 15 15 14 14 16 16 16 15 15 14 15 17 19 51 23 19 19 15 15 34 27 19 18 28 CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JOKE 94 75 56 34 20 15 21 30 42 44 43 44 51 60 60 33 17 10 12 220 82 15 58 42 31 35 19 17 11 33 9.9 4.5 3.0 1.6 .88 .62 .83 1.2 1.6 1.6 1.8 1.9 2.3 2.5 2.5 1.3 .69 .49 .68 128 5.3 .82 3.0 1.7 1.3 4.6 1.4 .86 .54 3.3 TOTAL 722 94.89 781 574.80 599 190.71 104 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR—Continued DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 SEDIMENT DISCHARGE, SUSPENDED MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (HG/L) (TONS/DAY) 21 17 17 16 16 16 16 29 24 16 15 17 17 15 64 24 18 18 18 17 26 18 16 16 18 23 17 16 28 20 18 JULY 85 77 83 91 91 73 57 48 62 52 52 53 55 55 285 224 88 16 13 14 92 79 59 29 21 53 18 10 18 30 29 TOTAL 627 —— YEAR • 17287 Estimated (TONS/DAY) , WATER YEAR OCTOBER 1996 TO SEPTEMBER MEAN MEAN CONCEN- SEDIMENT MEAN C DISCHARGE TRATION DISCHARGE DISCHARGE T (CFS) (MG/L) (TONS/DAY) (CFS) ( AUGUST SEPT 4.8 3.6 3.8 4.0 3.9 3.1 2.5 4.1 4.0 2.3 2.1 2.4 2.5 2.2 181 15 4.4 .78 .65 .71 6.5 3.8 2.6 1.3 1.6 3.5 .86 .43 1.8 1.6 1.4 273.23 33400.87 17 16 17 21 17 16 16 46 55 78 48 30 39 58 43 53 32 29 28 34 38 27 112 63 38 30 28 26 44 142 e78 1319 28 29 30 66 24 10 9 230 206 286 49 93 86 170 32 75 22 22 22 22 30 30 794 64 28 30 34 32 103 965 296 —— 1.3 1.2 1.4 3.8 1.1 .42 .40 128 68 160 7.1 7.7 11 71 4.0 13 1.9 1.7 1.8 2.5 4.4 2.2 834 13 2.9 2.4 2.5 2.3 33 2420 •101 3905.02 •34 •125 •44 •36 32 29 28 27 25 24 23 34 26 51 35 25 22 21 21 19 22 25 22 51 31 22 80 36 93 48 --- 1111 CONCEN- TRATION DISCHARGE (MO/L) (TONS/DAY) 405 1080 76 33 21 23 23 24 24 19 14 19 17 147 159 18 21 26 29 32 34 21 24 210 30 29 440 26 420 190 •429 »1070 •9.1 •3.3 1.8 1.8 1.7 1.7 1.6 1.2 .88 2.0 1.2 57 20 1.2 1.3 1.5 1.6 1.6 2.1 1.6 1.5 95 2.5 1.7 313 2.7 427 28 2484.58 RZO GRANDE DE ARECIBO BASIN 50028000 RZO TANAMA NEAR UTUADO, PR—Continued 105 DATE NOV 1996 17... MAY 1997 24... AUO 23... 30... SEP 01... DATE NOV 1996 17... MAY 1997 24... AUO 23... 30... SEP 01... LTEK QUALITY DATA, PARTICLE- SIZE DZS- TZME 2030 1825 2020 2030 2400 SED. SUSP. FALL DZAM. H FINER THAN .016 MM (70329) 62 47 70 35 CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 279 224 552 1730 881 SEP. SUSP. FALL DZAM. * FINER THAN .031 MM (70330) 75 63 83 47 WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DISTRIBUTION OF SUSPENDED SEDIMENT SEDI— SED* SEP* SEP. SEDI- MENT, SUS- PENDED (MG/L) (80154) 3100 2690 4970 14400 15800 SED. SUSP. SIEVE DZAM. H FINER THAN .062 MM (70331) 92 75 93 63 MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 2340 1620 7410 67300 37600 SED. SUSP. SIEVE DZAM. H FINER THAN .125 MM (70332) 98 92 98 81 SUSP. FALL DZAM. H FINER THAN .002 MM (70326) 30 18 30 13 15 SED. SUSP. SIEVE DZAM. * FINER THAN .250 MM (70333) 100 98 99 92 SUSP. FALL DZAM. H FINER THAN .004 MM (70327) 39 23 41 18 20 SED. SUSP. SIEVE DZAM. * FINER THAN .500 MM (70334) 100 99 100 98 SUSP. FALL DZAM. % FINER THAN .008 MM (70328) 51 32 55 25 29 SED. SUSP. SIEVE DZAM. * FINER THAN 1.00 MM (70335) 100 100 100 99 39 49 63 79 93 99 99 106 RIO ORANDE DE ARBCIBO BASIN 50028000 RIO TANAMA NEAR UTUADO—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 26... 26... 31... 31... NOV 17... 23... JAN 1997 14... MAR 20... JUL 11... SEP 02... 15... TIME 1925 2055 1635 1730 1935 0805 1608 0856 0700 0225 0705 DIS- CHARGE, INST. CUBIC rkaik PER SECOND (00061) 230 246 259 379 437 106 350 35 16 •221 37 SEDI- MENT, SUS- PENDED (MO/L) (80154) 4680 780 3760 1350 1520 150 1380 50 220 3680 364 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 2910 518 2630 1380 1790 43 1300 4.7 9.5 •2200 36 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 61 82 37 93 80 96 85 94 84 94 97 • Estlnat«d RIO GRANDE DE ARECIBO BASIN •-' V 50028400 RIO TANAMA AT CHARCO HONDO, PR LOCATION.—Lat 18°24'52", long 66°42'52>, Hydrologic Unit 21010002 on right bank at abandoned power house at Charco Hondo, 1.5 mi (2.4 km) upstream from mouth, and 4 mi (6 km) south of Arecibo. DRAINAGE AREA.--57.6 mi 2 (149.2 km2 ). PERIOD OF RECORD.—April 1969 to June 1971, October 1981 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 60 ft (18 m), from topographic map. REMARKS.—Records poor. Diversion 0.8 mi (1.3 km) upstream for municipal supply of Arecibo. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 107 DAY OCT NOV DEC JAN APR MAY JDN JUL AtJG SEP 1 145 178 2 113 142 3 126 126 4 123 117 5 116 111 6 150 107 7 130 103 8 101 99 9 105 102 10 96 e225 11 95 e225 12 92 146 13 103 161 14 155 108 15 263 108 16 129 175 17 110 247 18 253 232 19 146 224 20 124 149 21 113 146 22 322 147 23 186 167 24 155 134 25 139 130 26 153 109 27 300 103 28 208 103 29 187 107 30 197 117 31 188 TOTAL 4823 4348 MEAN 156 145 MAX 322 247 MXN 92 99 AC-FT 9570 8620 CFSM 7.01 6.53 IN. 8.08 7.29 STATISTICS OF MONTHLY MEAN MEAN 164 135 MAX 335 260 (WY) 1990 1982 MXN 72.1 50.4 (WY) 1983 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 108 96 93 90 88 85 84 83 80 95 e330 181 123 111 108 106 102 99 96 96 98 103 93 91 114 110 89 90 89 86 85 3302 107 330 80 6550 4.80 5.53 86 99 209 194 105 95 90 89 95 85 84 95 100 e226 e!74 94 88 83 84 264 338 e600 359 304 243 192 169 159 133 117 111 5164 167 600 83 10240 7.50 8.65 DATA FOR WATER 80.3 219 1982 36.4 1989 FOR 60.6 167 1997 22.3 1989 108 107 110 94 91 90 89 86 84 83 79 79 76 73 73 71 70 70 69 68 69 70 64 64 64 63 60 59 —— 2183 78.0 110 59 4330 3.51 3.66 YEARS 1969 50.9 106 1996 16.8 1989 59 59 59 60 59 57 55 55 55 53 51 51 50 49 49 50 48 57 66 93 56 53 50 49 48 48 48 61 70 66 79 1763 56.9 93 48 3500 2.56 2.95 - 1997 42.9 70.0 1971 16.6 1988 1996 CALENDAR YEAR 39552 108 1360 38 41 78450 4. 66. 187 83 49 Sep 10 Jul 27 Jul 22 87 28 56 51 52 50 50 48 48 47 47 48 46 45 45 45 43 44 43 44 46 47 51 73 81 52 46 44 42 39 38 35 —— 1446 48.2 81 35 2870 2.17 2.42 33 39 66 34 33 34 33 35 42 42 40 35 34 33 35 35 33 34 34 33 36 41 79 89 el!7 102 90 78 53 47 70 1539 49.6 117 33 3050 2.24 2.58 112 57 50 47 45 44 42 e37 e35 e35 e38 e40 e39 e38 e37 e35 e34 38 38 e63 69 46 44 42 38 41 64 46 38 39 —— 1371 45.7 112 34 2720 2.06 2.30 48 38 36 e35 e37 e39 e41 e44 e62 e39 37 38 44 46 97 108 62 47 50 43 62 45 40 38 38 56 72 44 65 92 61 1604 51.7 108 35 3180 2.33 2.69 69 47 42 45 45 40 37 58 146 136 113 70 91 157 192 118 134 88 53 89 140 103 97 156 76 60 52 50 91 177 132 2904 93.7 192 37 5760 4.22 4.87 e!31 221 134 90 80 75 73 71 70 68 68 74 87 77 122 82 77 72 71 69 70 78 82 83 109 75 119 127 125 127 —— 2807 93.6 221 68 5570 4.21 4.70 , BY WATER YEAR (WY) 66.9 141 1986 25.9 1989 128 371 1986 15.8 1989 88.2 196 1995 23.3 1989 FOR 1997 WATER YEAR 33254 91.1 600 33 34 2080 10.23 65960 4.10 55.72 158 77 38 Jan 22 May 1 May 14 Sep 1 Sep 1 63.9 120 1969 22.0 1989 WATER 87 124 46 2500 4 5 15000 17 63700 3 53 176 65 29 76.2 125 1991 35.1 1994 YEARS 1969 - .9 .9 Oct 7 .2 May 28 .4 May 22 May 18 .95 May 18 .96 .82 124 269 1996 44.9 1994 1997 1986 1994 1985 1989 1989 1985 1985 e Estimated 108 RIO GRANDE DE ARECIBO BASIN 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAMBALACHE, PR LOCATION.—Lat 18°27'20", long 66°42'10", Hydrologic Unit 21010002, at bridge on unimproved road, about 500 ft (152 m) upstream from Central Cambalache, near Highway 2, 13.9 mi (22.4 km) downstream from Dos Bocas Reservoir, 1.9 mi (3.1 km) downstream from Rio Tanama, and 1.6 mi (2.6 km) southeast of Arecibo. DRAINAGE AREA.—200 mi 2 (520 km2 ). PERIOD OF RECORD.--January 1963 to January 1965 (monthly measurements only), February 1965 to April 1969 (occasional measurements only). Hay 1969 to Sepetember 1983, October 1996 to September 1997. GAGE.--Water-stage recorder. Datum of gage is 3.73 ft (1.14 m) above mean sea level. REMARKS.--Records poor. Flow regulated by Lago Dos Bocas dam, 13.9 mi (22.4 km) upstream. Gage-height satellite telemetry at station. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate discharges and elevations above mean sea level of major floods at valley cross sections along Expressway PR-22 about 1.0 mi (1.6 km) above gage site are as follows: Aug. 8, 1899, 195,000 ftVs (5,520 mVs), gage-height, 24.4 ft (7.44 m); Sept. 13, 1928, 105,000 ftVs (2,970 mVs), gage-height, 21.6 ft (6.58 m); Oct. 13, 1954, 76,000 ftVs (2,150 mVs), gage-height. 19.1 ft (5.82 m); and Nov. 26, 1968, 21,000 ftVs (595 mVs) gage-height, 16.6 ft (5.06 m) . DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV FEB MAR MAY JUN JUL AUG 1 e963 932 2 e!160 361 3 e!020 292 4 911 515 5 838 352 6 e526 460 7 703 750 8 319 617 9 262 390 10 225 458 11 e!97 624 12 e!87 527 13 e238 695 14 e402 536 15 657 365 16 e682 493 17 e631 456 18 e792 1060 19 e468 1260 20 e321 1160 21 878 704 22 890 771 23 914 896 24 785 485 25 718 671 26 402 633 27 511 623 28 325 348 29 333 459 30 861 373 31 901 —— TOTAL 19020 18266 MEAN 614 609 MAX 1160 1260 MIN 187 292 AC-FT 37730 36230 CFSM 3 . 07 3 . 04 IN. 3.54 3.40 677 759 548 323 601 595 799 347 691 739 672 388 198 494 547 688 456 320 271 259 302 317 369 372 258 590 605 286 211 370 356 14408 465 799 198 28580 2.32 2.68 STATISTICS OF MONTHLY MEAN DATA MEAN 811 755 MAX 1577 1388 (WY) 1971 1978 MIN 404 299 (WY) 1983 1974 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 539 1327 1982 195 1972 220 255 295 558 332 321 e219 e284 e!43 e!30 412 213 300 678 645 472 440 327 347 472 1020 4120 1670 1100 1000 761 820 673 669 650 641 20187 651 4120 130 40040 3.26 3.75 FOR WATER 365 651 1997 155 1973 367 350 395 476 551 511 396 292 253 545 543 566 518 462 287 389 363 311 362 442 529 441 321 385 e330 e482 e535 492 ___ ___ —— 11894 425 566 253 23590 2.12 2.21 YEARS 1969 302 425 1997 152 1974 210 143 381 471 377 388 519 272 137 356 493 404 430 475 353 407 459 386 414 392 293 155 309 345 402 439 476 285 232 280 357 11040 356 519 137 21900 1.78 2.05 - 1997 328 627 1972 141 1977 343 365 186 371 280 225 106 290 364 428 462 198 117 99 253 457 452 502 265 158 182 236 452 444 258 137 456 358 304 386 —— 9134 304 502 99 18120 1.52 1.70 , BY WATER 387 641 1983 196 1975 387 410 291 227 211 274 309 310 175 428 244 314 419 252 386 304 119 307 417 164 103 90 174 203 251 349 369 167 200 194 141 8189 264 428 90 16240 1.32 1.52 YEAR (WY) 564 1192 1980 188 1977 154 101 315 447 412 264 214 140 190 105 244 157 90 81 74 86 122 132 95 94 135 110 211 137 89 85 109 90 81 82 —— 4646 155 447 74 9220 .77 .86 457 1220 1979 139 1977 FOR 1997 WATER YEAR 140534 385 4120 74 96 5750 10 68 278700 1 26 684 347 112 .74 .93 .14 Jan 22 Jun 15 Jun 24 Jan 22 Jan 22 Jun 15 272 464 300 153 101 87 79 107 163 85 116 103 77 74 186 188 123 148 151 128 199 221 170 268 190 102 125 237 448 423 376 5864 189 464 74 11630 .95 1.09 381 854 1979 189 1997 WATER 501 691 290 15900 60 86 26100 13. 50 363100 2. 34. 964 358 139 333 184 167 93 88 106 103 139 202 191 193 212 251 495 819 431 444 400 274 419 340 447 436 365 423 415 468 463 318 292 247 9758 315 819 88 19350 1.57 1.81 421 1269 1979 218 1974 YEARS 1969 Aug Aug Jun Aug 74 Aug Feb 51 05 191 570 668 575 435 452 266 394 471 359 330 200 152 114 149 221 153 147 149 101 143 104 103 120 148 97 128 240 455 493 —— 8128 271 668 97 16120 1.35 1.51 704 1866 1979 271 1997 - 1997 1979 1974 31 1979 4 1982 29 1977 31 1979 31 1979 26 1974 e Estimated RIO GRANDE DE ARECIBO BASIN 109 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAHBALACHE, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°27'20", long 66°42'10", Hydrologic Unit 21010002, at bridge on unimproved road, about 500 ft (152 m) upstream from Central Cambalache, near Highway 2, 8.3 mi (13.4 km) downstream from Dos Bocas Reservoir, 1.9 mi (3.1 km) downstream from Rio Tanama , and 1.6 mi (2.6 km) southeast of Arecibo. DRAINAGE AREA.--200 mi' (520 km2 ), approximately. PERIOD OF RECORD.--Water years 1963-66, 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 30... FEE 1997 21... JUN 05... AUG 26... TIME 0930 1230 1145 1050 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 451 214 158 185 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 250 268 271 325 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.2 6.5 7.9 7.6 TEMPER- ATURE WATER (DEG C) (00010) 24.0 23.5 27.5 27.0 TUR- BID- ITY (NTU) (00076) 59 2.6 3.6 8.2 OXYGEN, DIS- SOLVED (MG/L) (00300) 7.5 7.6 7.7 7.1 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 87 86 98 88 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) <10 <10 <10 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 3500 K180 40 K690 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 4200 K1100 K80 K130 OCT 30 FEB 21 JUN 05 AUG 26 OCT 30 FEB 21 JUN 05 AUG HARD- NESS TOTAL (MG/L DATE AS CAC03) (00900) 1996 100 1997 ... 110 98 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 <0.10 1997 ... ... <0.10 26... <0.10 K - non- ideal count CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 34 -- 34 30 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 16 -- 19 18 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 4.7 -- 6.2 5.5 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 143 -- 160 141 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 8.0 -- 9.6 8.6 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 174 -- 68.2 70.4 SODIUM AD- SORP- TION RATIO (00931) 0.3 -- 0.4 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 72 5 1 15 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 -- 2.0 2.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.900 0.790 0.400 0.690 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 98 110 110 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 <0.010 0.020 0.010 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -~ NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.920 0.790 0.420 0.700 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 11 -- 12 11 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.030 0.050 0.030 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 8.6 __ 11 10 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.38 <0.20 0.22 0.24 110 DATE OCT 1996 30... FEB 1997 21... JUN 05... AUG 26... RIO GRANDE DE ARECIBO BASIN 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAMBALACHE, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN/ TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 0.43 0.22 0.26 0.28 1.3 1.0 0.69 0.98 6.0 0.040 4.5 0.020 3.1 <0.020 4.3 <0.020 <1 <1 <100 <100 20 20 <1 <1 <1 20 DATE OCT 1996 30... FEB 1997 21... JUN 05... AUG 26... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- IiBHE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 2000 120 <1 120 25 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 PESTICIDE ANALYSES DATE JUN 1997 05... TIME 1145 PCB, TOTAL (UG/L) ALDRIN, TOTAL CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (UG/L) P,P'- P,P'- ENDO- DDD P,P'- DDT DI- DI- SULFAN, UNFILT DDE, UNFILT AZINON, ELDRIN I RECOVER TOTAL RECOVER TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) luwsii; luw/ii/ luu/ii; iuu/ii; iuw/ii; luw/u; iuu/u/ luu/u; iuu/u/ (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) (39390) (39398) JUN 1997 05... HEPTA- CHLOR, TOTAL (UG/L) (39410) HEPTA- CHLOR EPOXIDE TOTAL (UG/L) (39420) LINDANE TOTAL (UG/L) (39340) MALA- THION, TOTAL (UG/L) (39530) METH- OXY- CHLOR, TOTAL (UG/L) (39480) METHYL PARA- THION, TOTAL (UG/L) (39600) MIREX, TOTAL (UG/L) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE JUN 1997 05... PARA- PCNS THION, UNFILT TOTAL RECOVER (UG/L) (UG/L) (39540) (39250) PER- THANE TOTAL (UG/L) (39034) TOX- APHENE, TOTAL (UG/L) (39400) <0.010 <0.100 <0.100 <1.00 TOTAL TRI- THION (UG/L) (39786) <0.010 2,4-D, TOTAL (UG/L) (39730) 2,4,5-T TOTAL (UG/L) (39740) 2, 4-DP TOTAL (UG/L) (82183) SILVEX, TOTAL (UG/L) (39760) 0.040 <0.010 <0.010 <0.010 111 ATLANTIC OCEAN Drainage bounoan** indeterminate in limestone terrane Ri'o inoBtfn t>4lin 7-r Do«.ft J &0*m EXPLANATION AOSSO SURFACE-WATER STATION AND NUMBER Toso/ QUAUTY-OF-WATER STATION AND NUMBER •210 WELL AND WELL NUMBER |032290 LAKE-ELEVATION STATION rt „ „ „ „ c ft *„ OMPTPPC JL AND NUMBER 0123456 KILOMETERS I I ! I 01234 MtLES Figure 15.—Rio Grande de Manati basin. 112 RIO GRANDE DE MANATI BASIN 50030460 RIO OROCOVXS AT OROCOVIS, PR LOCATION.--Lat 18°13'25", long 66°23'34", Bydrologic Unit 21010001, on right bank, 0.4 mi (0.6 tan) couth of junction of Highway* 155 and 156 in Oroeovic, 2.1 mi (3.38 tan) upctream from Rio Botijai, and 250 ft (76 m) upctream from bridge on Highway 599. DRAINAGE AREA.--5.03 mi* (13.03 tan»). PERIOD OF RECORD.—April 1981 to September 1982, October 1988 to current year. GAGE.—Water-stage recorder. Elevation of gage is 500 ft (152 m), from topographic map. REMARKS.—Records poor. Low flow affected by diversions for water supply. Gage-height and precipitation catellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 3.7 6.2 2 3.1 5.3 3 7.9 4.3 4 4.1 4.3 5 4.0 3.8 6 10 3.6 7 5.1 3.3 8 4.5 4.3 9 4.1 5.0 10 3.6 3.9 11 3.3 5.2 12 3.2 4.0 13 3.2 2.9 14 3.4 2.7 15 3.3 2.6 16 3.1 2.5 17 3.0 2.5 18 2.4 50 19 4.9 8.1 20 3.8 7.1 21 2.7 4.8 22 2.2 5.2 23 2.8 13 24 2.1 26 25 1.7 19 26 15 7.3 27 8.0 4.2 28 11 4.6 29 39 3.9 30 21 21 31 9.3 TOTAL 198.5 240.6 MEAN 6.40 8.02 MAX 39 50 MIN 1.7 2.5 AC-FT 394 477 CFSM 1.27 1.59 IN. 1.47 1.78 STATISTICS OF MONTHLY MEAN MEAN 16.2 6.91 MAX 58.0 15.2 (WY) 1990 1991 MIN 1.95 1.56 (WY) 1994 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 12 5.9 4.4 3.9 3.3 2.6 2.7 2.5 2.4 2.6 62 23 9.4 5.8 4.5 4.6 3.4 3.1 2.7 3.1 3.1 2.7 3.2 3.0 2.9 2.5 2.7 2.7 4.0 3.5 3.2 197.4 6.37 62 2.4 392 1.27 1.46 DATA 5.16 15.8 1982 .65 1995 2.9 e2.9 e5.8 e5.8 e3.1 e2.7 e2.6 e2.4 e2.4 e2.4 2.8 3.2 3.1 3.3 3.2 2.1 2.2 2.1 3.1 6.2 43 35 24 31 19 9.1 5.6 5.0 3.9 3.4 3.4 246.7 7.96 43 2.1 489 1.58 1.82 3.3 3.2 3.5 3.3 3.7 3.8 2.8 2.8 2.4 2.6 2.2 3.2 1.9 1.9 1.8 1.6 1.7 2.1 e2.9 e2.0 el. 8 el. 7 el. 5 el. 5 el. 5 el. 6 el. 4 el. 3 el. 3 el. 3 el. 3 el. 2 el. 5 el. 4 el. 2 el. 2 el. 2 el. 2 el.l el.l el.l el.l el.O el.O el.O el.O el. 2 el.l el.l el.O el.O e.96 el.l el.l el. 9 el. 9 —— e!5 —— —— 65.0 2.32 3.8 1.3 129 .46 .48 FOR WATER YEARS 1981 6.55 34.3 1992 .77 1995 3.52 15.7 1996 .96 1995 e2.3 el. 2 52.06 1.68 15 .96 103 .33 .39 - 1997 1.82 3.07 1996 .90 1994 FOR 1996 CALENDAR YEAR 4261.2 11.6 1570 1.1 1.2 8450 2.31 31.51 11 2.8 1.4 Sep 10 Mar 31 Aug 26 el. 2 el.l el. 2 e.95 el.O el.l el.l el.l el.l el.l el.O el.O el.l el.O el.O el.O e.98 e.90 e.86 el.O el. 4 1.1 1.2 1.3 1.2 .90 1.0 .95 1.0 1.3 —— 32.14 1.07 1.4 .86 64 .21 .24 .78 .88 1.1 1.1 1.2 .99 .97 .88 .81 1.1 1.0 .83 .86 .81 .79 .78 1.0 .73 .79 .87 .80 .73 .91 1.1 1.0 .76 .68 .63 .63 .61 .62 26.74 .86 1.2 .61 53 .17 .20 .63 .63 .52 .48 .44 .50 .47 .42 .48 .90 .60 .43 .49 .57 .49 .43 .36 .52 .36 .33 .35 .42 .55 .55 .38 .36 1.0 2.8 8.6 6.1 —— 31.16 1.04 8.6 .33 62 .21 .23 1.9 .40 .56 .24 .45 .51 1.3 1.0 .25 .23 .43 .41 .86 .85 .64 .33 .50 1.1 1.6 6.4 1.9 .95 1.0 1.6 2.1 2.1 .95 1.4 1.1 1.2 11 45.26 1.46 11 .23 90 .29 .33 10 6.4 3.7 3.2 1.6 1.4 1.6 1.3 11 9.2 3.0 2.1 12 12 3.2 1.7 3.7 2.4 1.1 1.1 1.6 2.1 1.7 1.7 2.6 1.9 1.6 1.1 .90 .89 1.1 108.89 3.51 12 .89 216 .70 .81 2.1 2.3 .84 .86 .85 .90 1.4 .78 .79 .83 .85 1.5 1.8 1.4 1.0 .81 .97 1.0 1.2 1.2 1.6 2.7 3.4 1.4 1.1 1.7 2.8 2.7 4.1 2.7 47.58 1.59 4.1 .78 94 .32 .35 , BY WATER YEAR (WY) 5.24 21.0 1993 .93 1995 FOR 1997 1292 3 62 388 7 2560 9 6 1 14.0 45.9 1995 .86 1997 WATER YEAR .03 .54 Dec 11 .23 Jul 10 .40 Jun 16 Nov 18 .53 Nov 18 .70 .56 .3 .7 .63 4.38 15.2 1992 .88 1994 3.56 9.07 1996 .88 1994 WATER 7 11 1 1570 8890 17 5370 1 20 11 1 3.67 12.3 1989 1.03 1982 YEARS 1981 .41 .8 .49 .20 .33 .38 .47 .02 .9 .85 Sep Oct Oct Sep Sep 19.5 73.0 1996 .88 1994 - 1997 1996 1994 10 1996 4 1992 11 1992 10 1996 10 1996 e Estimated 113 RIO QRANDE DE MANATI BASIN 50030700 RIO OROCOVIS NEAR OROCOVIS, PR WATER-QUALITY RECORDS LOCATION.—L»t 18°14'20", long 66°22'58", at flat low bridge about 300 ft (91 m) northwest of Highway 568, 1.0 mi (1.6 km) north of Orocovis plaza. DRAINAGE AREA.—10.1 mi 1 (26.2 kma ). PERIOD OF RECORD.—Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... OCT 17 FEB 25 JUN 11 SEP 10 OCT 17 FEB 25 JUN 11 SEP 10 OCT 17 FEB 25 JUN 11 SEP 10 K - DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEC C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1100 12 296 7.5 24.0 0.60 7.9 96 <10 K1400 940 0930 10 330 7.6 20.0 2.5 8.0 90 <10 K1300 210 1310 5.3 352 8.4 27.0 0.23 7.0 94 <10 K180 3200 0930 2.3 378 8.2 26.0 0.35 6.8 88 <10 K160 260 ALKA- BARD- MAGNE- SODIUM POT AS- LINITY CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, WAT WH SULFATE RIDE, DATE 1996 ... 1997 ... ... ... DATE 1996 1997 ... ... ... DATE 1996 ... 1997 ... ... ... TOTAL (MG/L AS CACO3) (00900) 120 .. 140 160 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 0.21 0.23 0.23 DIS- SOLVED (MG/L AS CA) (00915) 28 — 36 41 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 31 — 31 29 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.3 1.2 1.3 DIS- SOLVED (MG/L AS MG) (00925) 11 — 13 14 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 180 — 212 224 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.0 5.6 5.2 5.7 DIS- SOLVED (MG/L AS NA) (00930) 13 .. 15 16 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 5.65 — 3.04 1.42 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.070 0.060 0.130 0.070 SORP- TION RATIO (00931) 0.5 — 0.5 0.6 RESIDUE TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) (00530) 2 <1 <1 <1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — DIS- SOLVED (MG/L AS K) (00935) 2.1 __ 1.7 1.7 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.00 1.00 0.940 1.00 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — TOT FET FIELD MG/L AS CACO3 (00410) 120 130 150 160 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — <10 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.00 1.10 0.950 1.10 CADMIUM HATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — DIS- SOLVED (MG/L AS S04) (00945) 8.1 -. 8.3 7.8 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.040 0.030 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 .. <1 — DIS- SOLVED (MG/L AS CL) (00940) 15 ._ 17 18 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 0.20 0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 .. <10 — non- ideal count 114 RIO ORANDE DE MANATI BASIN 50030700 RIO OROCOVIS NEAR OROCOVIS, PR—Continued WATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS H6) (71900) SELE- NIUM, TOTAL (UO/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LBNE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 130 60 <1 <1 20 14 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.02 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR 775 LOCATION.--Lat 18°17'45", long 66°24'47", Hydro!ogic Unit 21010001, on right bank , 0.1 mi (0.2 km) downstream from Quebrada Perchas, 0.8 mi (1.3 km) upstream from Rio Sana Muerto, and 2.2 mi (3.5 km) south of Morovis. DRAINAGE AREA.--55.2 mi* (143.0 km')- PERIOD OF RECORD.—January 1965 to current year. GAGE.--Water-stage recorder and concrete control. Elevation of gage is 440 ft (134 m), from topographic map. Feb. 2, 1966 to Apr. 27, 1967, staff gage read twice daily. REMARKS.--Records poor. Public water-supply pumpage, about 300 ft (91 m) above the station, influences low-flow discharges. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 69 e58 2 66 e52 3 67 e47 4 78 e48 5 63 e45 6 71 045 7 72 045 8 59 49 9 56 54 10 55 57 11 54 55 12 49 65 13 51 59 14 50 54 15 49 52 16 57 41 17 47 40 18 45 e!30 19 44 e!30 20 48 ellO 21 60 e!20 22 59 e!40 23 46 e!70 24 46 0200 25 47 0210 26 0160 0120 27 0210 092 28 0120 094 29 0120 096 30 0140 0150 31 074 —— TOTAL 2232 2628 MEAN 72.0 87.6 MAX 210 210 MIN 44 40 AC -FT 4430 5210 CFSM 1.30 1.59 IN. 1.50 1.77 STATISTICS OF MONTHLY MEAN MEAN 152 143 MAX 1037 491 (WY) 1971 1971 MIN 24.0 11.4 (WY) 1978 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 0160 ellO 090 078 072 064 e60 060 058 e!70 0400 elSO elOO 086 e82 elOO e84 e72 e62 e58 e60 e60 e58 e52 e51 050 e58 056 e80 084 e72 2797 90.2 400 50 5550 1.63 1.88 064 058 0210 0140 090 070 058 054 064 084 058 056 e54 066 e80 e56 e52 049 e54 elSO 0800 02100 0700 0520 0420 e250 e!90 elSO 138 117 110 7062 228 2100 49 14010 4.13 4.76 DATA FOR WATER 108 522 1966 8.65 1995 FOR 82.1 228 1997 10.4 1995 123 121 103 93 95 96 82 80 81 82 74 73 80 74 72 67 66 66 71 79 96 91 71 68 66 65 64 59 ... ... 2258 80.6 123 59 4480 1.46 1.52 YEARS 1965 63.5 179 1969 15.3 1994 57 59 66 74 91 74 60 63 62 53 53 53 54 55 57 57 57 57 52 49 46 46 42 41 39 42 43 61 154 128 62 1907 61.5 154 39 3780 1.11 1.29 - 1997 64.4 226 1972 12.7 1984 1996 CALENDAR YEAR 31831 87. 7500 13 14 63140 1. 21. 140 46 21 0 Sep 10 Jul 6 Jul 1 58 45 51 49 63 851 49 46 41 41 41 39 39 40 39 37 34 34 35 33 32 37 44 42 34 32 32 30 29 32 29 27 --- 1162 38.7 63 27 2300 .70 .78 28 28 28 28 27 26 25 25 25 26 27 24 24 24 23 23 23 25 23 21 22 26 35 080 elSO e94 068 e38 e33 59 35 1143 36.9 150 21 2270 .67 .77 32 28 29 28 26 24 22 21 21 21 19 20 20 21 19 17 17 18 23 23 19 17 16 16 17 16 16 15 14 14 609 20.3 32 14 1210 .37 .41 16 14 13 11 11 11 13 24 11 11 11 12 12 11 10 11 9.7 15 21 21 27 15 12 11 11 11 10 9.3 9.0 9.4 12 405.4 13.1 27 9.0 804 .24 .27 19 11 9.9 17 11 9.7 9.3 8.6 8.6 13 11 10 19 46 15 12 21 47 17 12 11 11 13 12 12 11 9.3 11 13 12 13 455.4 14.7 47 8.6 903 .27 .31 10 9.2 8.2 8.1 8.1 7.7 7.7 7.8 8.4 9.4 7.6 7.4 9.3 9.9 8.7 7.7 7.6 7.2 7.3 7.4 8.3 12 18 9.8 15 16 13 14 10 19 299.8 9.99 19 7.2 595 .18 .20 , BY WATER YEAR (WY) 106 412 1969 8.80 1995 157 915 1985 15.7 1994 60.2 173 1987 6.75 1994 FOR 1997 WATER YEAR 22958.6 62.9 2100 7.2 7.7 unknown unknown 45540 1.14 15.47 113 46 11 Jan 22 Sep 18 Sep 15 Jan 22 Jan 22 45.3 157 1979 5.54 1994 WATER 94. 248 24. 17100 3. 4. 48000 17. 68510 1. 23. 170 48 21 53.9 435 1979 9.70 1984 YEARS 1965 6 2 May 5 May 0 Jul May 89 May 71 28 101 432 1996 6.87 1994 - 1997 1971 1994 18 1985 1 1995 22 1994 18 1985 18 1985 e Estimated 116 PERIOD RIO GRANDE DE MMJATI BASIN 50031200 RIO GRANDE DE HANATI NEAR NOROVIS, PR—Continued MATER-QUALITY RECORDS OF RECORD.—Water years 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- CHARGE, INST. CUBIC FEET TIME PER SPE- CIFIC CON- DUCT- ANCE PH WATER WHOLE FIELD TEMPER- (STAND- ATURE ARD WATER OXYGEN, OXYGEN DIS- DEMAND, SOLVED CHEM- TUR- OXYGEN, (PER- ICAL BID- DIS- CENT (HIGH ITY SOLVED SATUR- LEVEL) OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) 0915 1215 1050 1230 46 63 18 9.4 238 290 304 312 7.0 8.0 8.2 8.2 25.5 25.0 28.5 30.5 0.40 1.5 4.3 6.4 8.1 10.1 8.1 8.6 98 121 105 117 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K120 K10 K49 K140 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 100 K40 K70 K54 OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MO) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS S04) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 110 26 120 28 130 31 11 12 13 13 14 15 0.5 0.5 0.6 2.8 2.1 1.8 150 110 120 130 <0.5 <0.5 8.0 8.7 6.8 16 17 17 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 24 — SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 191 — SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 23.8 — RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 2 <1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.670 0.710 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 <0.010 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.680 0.720 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.020 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.22 0.10 27 0.11 27 180 190 8.65 4.80 0.140 <0.010 0.140 0.030 0.25 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <0.20 0.24 0.28 0.80 0.96 0.42 3.5 4.2 1.9 <0.020 0.030 0.020 <100 <100 30 <1 non-ideal count RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 117 DATE OCT 1996 17... PEB 1997 25... JUN 11... SEP 10... IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L 70 230 MANGA- NESE, MERCURY TOTAL TOTAL RECOV- ERABLE RECOV- ERABLE (UG/L (UG/L SILVER, ZINC, SELE- TOTAL TOTAL NIUM, RECOV- RECOV- CYANIDE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 30 <0.10 30 <0.10 <1 <1 <1 <1 <0.010 <1 <0.010 METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 <0.01 118 RIO GRANDE DE MANATI BASIN 50032290 LAGO EL GUINEO AT DAMSITE NEAR VTLLALBA, PR LOCATION.—Lat 18°09'41", long 66°31'36", Hydrologic Unit 21010001, at damsite on Rio Toro Negro, 3.0 mi (4.8 km) northwest from Vi11alba plaza and 1.9 mi (3.1 km) northeast of Cerro Maravillas. The reservoir itself fixes the territorial limits between the Municipality of Ciales and Orocovis. DRAINAGE AREA.—1.64 mi 2 (4.25 tan1 ). ELEVATION RECORDS PERIOD OF RECORD.—May 1988 to current year. Prior to October 1994, published as Lago El Guineo at Damsite. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago El Guineo was completed in 1931. It provides a maximum storage of approximately 2,180 ac-ft (2.688 hm3 ) for power and irrigation. Waters are discharged through an outlet power tunnel into the Rio Toro Negro and coveyed to the head water works of Toro Negro Hydroelectric Plant No.2, for energy generation at Toro Negro Hydroelectric plant No.l, and are discharged into the Guayabal Reservoir to be later used for irrigation at South Coast Irrigation System. The dam is rockfill with a vertical concrete corewall, rock toes, and riprap facing of upstream slope, with a total length of 565 ft (172 m), a maximum structural height of 125 ft (38 m) to top of corewall. At a maximum reservoir water surface elevation the uncontrolled morning-glory tunnel spillway crest has an elevation of 2,966 ft (904 m) above mean sea level and a design capacity of 7,000 ftVs. The dam is owned by Puerto Rico Electric Power Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.—Maximum elevation 2,961.70 ft (902.73 m), Oct. 21, 1990; rainimun elevation, 2,919.79 ft (899.95 m), May 27, 1988. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 2,961.12 ft (902.55 m), Nov. 23; minimun elevation, 2,927.61 ft (892.34 m). May 23. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 2,872 2,919 2,925 Contents, in acre-feet 0 361 491 Elevation, in feet 2,943 2,950 2,961 Contents, in acre-feet 1,029 1,308 1,852 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT NOV DEC APR MAY JUL AUG SEP 2956.86 2956.43 2956.34 2955.93 2956.14 2956.34 2955.82 2955.28 2954.76 2954.39 2953.91 2954.07 2954.23 2953.76 2953.34 2952.89 2953.15 2953.50 2954.17 2954.68 2954.81 2955.10 2955.34 2955.15 2954.92 2955.71 2955.89 2956.05 2956.08 2955.81 2955.95 2956.10 2956.23 2956.38 2956.70 2957.24 2957.44 2957.13 2957.26 2956.91 2957.04 2958.07 2959.26 2959.56 2959.37 2960.83 2960.65 2960.95 2960.36 2959.80 2959.01 2959.04 2958.88 2959.09 2959.27 2959.32 2959.49 2959.65 2959.62 2959.58 2959.47 2959.07 2958.63 2958.81 2958.97 2959.00 2959.02 2958.99 2958.89 2958.90 2959.04 2959.15 2959.14 2958.94 2959.05 2958.85 2958.69 2958.71 2958.88 2958.99 2959.09 2958.68 2959.22 2958.89 2958.41 2958.54 2958.65 2959.07 2959.53 2959.25 2959.15 2959.28 2959.39 2959.58 2959.72 2960.13 2960.44 2960.53 2959.99 2959.42 2957.93 2958.12 2958.24 2957.87 2957.53 2957.19 2956.86 2956.96 2957.08 2956.64 2956.01 2955.38 2954.90 2954.53 2954.59 2954.68 2954.76 2954.23 2953.70 2953.36 2952.81 2952.90 2952.97 2952.47 2951.93 2950.14 2950.24 2949.66 2949.04 2948.43 2947.99 2948.06 2948.16 2948.24 2947.67 2947.08 2946.47 2945.88 2945.29 2945.38 2945.45 2945.53 2945.11 2944.91 2944.39 2943.92 2943.99 2944.05 2943.52 2942.97 2942.12 2941.58 2941.68 2941.15 2941.25 2941.29 2941.10 2940.79 2940.56 2940.36 2940.21 2940.28 2940.33 2939.65 2938.90 2938.27 2937.63 2937.05 2937.10 2937.16 2937.24 2936.58 2936.66 2936.71 2936.79 2934.31 2933.79 2933.95 2934.01 2933.30 2932.74 2932.46 2932.17 2932.17 2932.35 2932.43 2932.16 2932.24 2931.96 2931.65 2931.34 2931.40 2931.46 2931.25 2930.58 2929.54 2928.36 2928.12 2928.20 2928.27 2932.16 2931.26 2929.88 2928.60 2929.35 2927.90 2928.60 2928.68 2928.76 2928.84 2928.92 2929.00 2929.07 2929.14 2929.20 2929.26 2929.32 2929.38 2929.50 2929.63 2929.69 2929.77 2929.82 2929.87 2929.91 2930.34 2930.39 2930.44 2930.39 2930.46 2930.47 2930.56 2930.62 2930.67 2930.71 2930.67 2930.74 2930.79 2930.62 2930.66 2930.71 2930.75 2930.82 2930.97 2931.36 2931.53 2931.62 2931.54 2931.59 2931.62 2930.67 2930.71 2930.84 2930.89 2930.79 2930.83 2930.86 2932.06 2932.89 2933.72 2933.96 2934.09 2934.98 2937.43 2937.31 2937.54 2937.74 2937.26 2937.26 2936.72 2935.96 2935.29 2935.39 2935.62 2935.15 2936.79 2937.01 2937.16 2937.29 2937.42 2937.51 2937.63 2937.72 2937.50 2937.60 2937.70 2937.89 2937.99 2938.07 2938.15 2938.23 A A 2938.40 2938.51 2938.60 2938.70 2938.63 2938.51 2938.37 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 2955.16 2959.38 2959.16 2959.56 2951.37 2942.41 2936.84 2931.54 2930.00 2931.67 2935.25 2938.45 27 2955.37 28 2955.15 29 2954.93 30 2955.30 31 2955.52 MAX 2956.86 MIN 2952.89 CAL YR 1996 WTR YR 1997 2959.07 2959.36 2958.84 2959.00 —— 2960.95 2955.71 MAX 2961. MAX 2960. 2959.26 2959.37 2959.46 2959.15 2958.76 2959.65 2958.63 05 MIN 95 MIN 2959.06 2958.57 2958.10 2957.65 2957.77 2960.53 2957.65 2936.81 2927.90 2950.78 2950.18 —— 2958.24 2950.18 2942.49 2942.59 2942.81 2942.90 2942.58 2950.24 2942.41 2936.91 2936.21 2935.54 2934.98 2942.12 2934.98 2933.72 2933.30 2932.65 2931.95 2932.06 2934.31 2928.12 2930.10 2930.15 2930.24 2930.30 2932.16 2927.90 2931.71 2931.75 2931.46 2931.51 2931.31 2931.75 2930.34 2934.56 2935.92 2936.25 2936.46 2936.63 2937.74 2930.67 2938.53 2938.61 2939.35 2939.48 —— 2939.48 2936.79 A No gage-height record RIO GRANDE DE MANAT1 BASIN 50032590 LAGO DE MATRULLAS AT DAMSITE NEAR OROCOVIS, PR 119 LOCATION.--Lat 18°12'46", long 66°28'50", Bydrologic Unit 21010001, in shelter house at damsite, and 5.8 mi (9.3 km) southwest of Orocovis. DRAINAGE AREA.--4.46 mi 2 (11.55 km»). ELEVATION RECORDS PERIOD OF RECORD.—Hay 1988 to current year. Prior to October 1994, published as Lago de Matrullas at Damsite. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Matrullas was completed in 1934. The dam is an earthfill structure about 120 ft (37 m) height, a top width of 30 ft (9 m) and a length of 710 ft (216 m), and has a maximum storage capacity of about 4,274 ac-ft (5.220 hra3 ) at top of dam elevation. The Matrullas Dam is owned by the Puerto Rico Electric Power Authority and is part of the Toro Negro Hydroelectric Project; a project developed by the P.R.E.P.A. for the primary purpose of generating electric power. Discharges from the Power Plants are collected by the Jacaguas River which flows into Guayabal Dam, at which dam they are regulated for irrigation of lands served by the Juana Diaz Canal. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 2,419.90 ft (737.58 m), Sept. 10, 1996; minimum elevation, 2,375.55 ft (724.06 m), Sept. 24, 25, 1994. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 2,416.16 ft (736.44 m), Jan. 21; minimum elevation, 2,398.96 ft (731.20 m), Aug. 8. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 2,338 2,360 Contents, in acre-feet 2 302 Elevation, in feet 2,399 2,420 Contents, in acre-feet 1,845 3,331 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN 2415.24 A 2415.22 2415.20 2415.47 A 2415.50 2415.37 2415.29 2415.24 2415.18 2415.42 2415.55 2415.41 2415.32 2415.24 2415.24 2415.19 2415.57 2415.91 2415.57 2415.45 2415.41 2415.34 2415.34 2415.70 2415.71 2415.56 2415.93 2415.63 A 2415.93 2415.18 A A A A A A A A A A A A A A A A A A A A A 2415.68 2415.76 2415.65 2415.55 2415.47 2415.43 2415.68 2415.50 2415.74 --- 2415.76 2415.43 2415.73 2415.60 2415.55 2415.54 2415.50 2415.47 2415.66 2415.69 2415.53 2415.50 2415.83 2415.63 2415.57 2415.70 2415.72 2415.60 2415.53 2415.48 2415.45 2415.45 2415.65 2415.69 2415.53 2415.39 2415.47 2415.31 2415.23 2415.49 2415.64 2415.44 2415.32 2415.83 2415.23 2415.46 2415.46 2415.69 2415.68 2415.66 2415.66 2415.47 2415.38 2415.30 2415.19 2415.41 2415.58 2415.80 2415.56 2415.39 2415.29 2415.18 2415.44 2415.78 2415.70 2416.15 2415.82 2415.64 A 2415.51 2415.69 2415.57 2415.53 2415.50 2415.48 2415.47 2416.15 2415.18 2415.67 2415.68 2415.59 2415.58 2415.57 2415.56 2415.55 2415.65 2415.66 2415.56 2415.45 2415.38 2415.40 2415.41 2415.58 2415.63 2415.64 2415.55 2415.56 2415.57 2415.54 2415.62 2415.63 2415.55 2415.50 2415.49 2415.46 2415.44 ___ ___ --- 2415.68 2415.38 2415.58 2415.63 2415.53 2415.48 2415.48 2415.45 2415.41 2415.58 2415.62 2415.50 2415.42 2415.37 2415.31 2415.23 2415.38 2415.34 2415.27 2415.20 2415.14 2415.08 2414.99 2415.12 2415.25 2415.17 2415.09 2415.02 2414.89 2415.07 2415.27 2415.41 2415.25 2415.63 2414.89 2415.07 2414.94 2414.77 2414.63 2414.75 2414.87 2414.68 2414.56 2414.45 2414.33 2414.14 2414.25 2414.35 2414.09 2413.82 2413.60 2413.37 2413.26 2413.35 2413.44 2413.54 2413.33 2413.41 2413.49 2413.57 2413.65 2413.74 2413.52 2413.27 2413.02 --- 2415.07 2413.02 2412.76 2412.47 2412.55 A A A A A A A A A A 2410.80 2410.53 2410.26 2410.35 2410.42 2410.14 2409.85 2409.58 2409.30 2409.03 2409.17 2409.29 2409.90 2409.76 2409.55 2409.28 2409.02 2409.11 2412.76 2409.02 2409.20 2408.86 2408.58 2408.23 2407.94 2407.68 A A A A A A A A A A A A 2405.24 2404.89 2404.81 2404.74 2404.36 2404.06 2403.74 2403.41 2403.01 2403.06 2403.10 2402.90 --- 2409.20 2402.90 2402.73 2402.50 2402.25 2402.27 2402.27 2402.29 2402.02 2401.76 2401.47 2401.20 2400.91 2400.93 2400.95 2400.72 2400.44 2400.19 2399.90 2399.67 2399.80 2399.97 2400.04 2399.95 2399.86 2399.77 2399.81 2399.85 2399.88 2399.92 2399.82 2399.74 2399.67 2402.73 2399.67 2399.52 2399.53 2399.60 2399.46 2399.34 2399.22 2399.10 2400.01 2402.17 2402.39 2402.37 2402.38 2403.25 2403.36 2403.37 2403.49 2403.61 2403.55 2403.50 2403.34 2403.05 2402.89 2402.96 2403.15 2403.10 2403.02 2402.87 2403.76 2403.89 2404.03 2404.23 2404.23 2399.10 2404.37 2407.64 2407.94 2408.01 2408.06 2408.20 2408.32 2408.29 2408.12 2408.08 2408.03 2408.06 2408.17 2408.26 2408.22 2408.15 2408.24 2408.31 2408.37 2408.45 2408.54 2408.55 2408.62 2408.71 2408.74 2408.79 2408.93 2409.02 2409.19 2409.24 —— 2409.24 2404.37 CAL YR 1996 WTR YR 1997 MAX 2416.52 MAX 2416.15 MIN 2411.50 MIN 2399.10 A No gage-height record 120 RIO GRANDE DE MANATI BASIN 50034000 RIO BAUTA NEAR OROCOVXS, PR LOCATION.--Lat 18°14'10", long 66°27'18", Hydrologic Unit 21010001, on left bank, at bridge on Highway 157 (12.1 km), and 4.2 mi (6.8 km) west of Orocovis. DRAINAGE AREA.--16.7 mi 1 (43.3 km 2 ). PERIOD OF RECORD.--February 1959 to April 1966 (annual low-flow measurements only), February to September 1969 (occasional measurements only), October 1969 to September 1982, October 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 772.82 ft (235.556 m) above mean sea level. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV 1 27 19 2 37 17 3 30 16 4 26 14 5 38 13 6 34 13 7 28 13 8 25 13 9 22 17 10 22 26 11 21 29 12 21 27 13 20 19 14 19 16 15 18 15 16 16 16 17 16 18 18 17 88 19 19 72 20 21 58 21 19 56 22 16 62 23 15 94 24 15 109 25 14 81 26 27 51 27 44 38 28 26 37 29 41 34 30 41 61 31 23 TOTAL 758 1142 MEAN 24.5 38.1 MAX 44 109 MIN 14 13 AC-FT 1500 2270 CFSM 1.46 2.28 IN. 1.69 2.54 STATISTICS OF MONTHLY MEAN MEAN 84.5 52.6 MAX 392 205 (WY) 1971 1971 MIN 14.6 7.12 (WY) 1994 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 61 43 35 31 29 27 26 26 25 25 131 76 49 38 34 34 33 31 29 28 28 27 25 24 24 24 24 23 24 24 24 1082 34.9 131 23 2150 2.09 2.41 DATA 27.9 108 1971 4.29 1995 JAN 23 23 43 43 28 24 23 21 21 21 21 21 21 26 25 21 21 21 35 47 6212 e!77 e!24 elOl 681 659 e44 642 636 634 632 1471 47.5 212 21 2920 2.84 3.28 FEB 633 630 629 628 628 626 626 625 625 625 625 624 625 624 623 622 621 621 24 24 24 22 21 21 20 21 19 19 ___ ___ --- 675 24.1 33 19 1340 1.44 1.50 FOR WATER YEARS 1969 21.2 83.4 1992 3.66 1995 15.1 40.1 1996 5.70 1994 MAR 18 18 18 17 20 19 18 18 18 17 16 16 16 16 15 15 15 15 16 15 15 15 14 14 14 14 14 15 23 18 14 506 16.3 23 14 1000 .98 1.13 - 1997 15.1 59.9 1972 4.18 1994 FOR 1996 CALENDAR YEAR 41802 114 19500 8 8 82920 6 93 76 16 10 .6 Sep 10 .3 Jul 6 .8 Jul 1 .84 .12 APR 14 14 16 612 ell elO 69.5 69.5 69.5 69.4 69.2 69.2 69.4 68.8 68.8 68.7 68.5 68.0 67.5 ell e!3 616 e!4 612 elO 69.0 68.6 68.0 67.6 7.0 --- 309.2 10.3 16 7.0 613 .62 .69 MAY 7.5 12 8.2 7.3 7.3 6.6 7.0 7.2 7.4 7.8 7.7 7.8 8.1 7.7 7.0 7.1 7.7 8.3 7.6 7.4 7.7 7.9 8.5 14 14 13 13 15 9.6 8.3 7.1 272.8 8.80 15 6.6 541 .53 .61 JUN 7.5 7.4 7.4 6.7 6.2 5.7 6.0 66.0 6.2 66.5 66.2 6.4 6.3 6.7 6.2 5.6 5.5 5.3 5.9 6.1 6.1 6.1 5.7 5.7 6.6 6.3 5.9 6.8 11 32 218.0 7.27 32 5.3 432 .44 .49 JUL 15 ell 69.0 65.0 65.0 65.0 66.0 68.8 64.2 64.2 64.2 64.4 64.4 64.2 63.9 65.5 63.9 3.6 4.3 5.1 6.9 4.4 4.1 3.9 3.9 3.8 4.4 4.6 4.6 4.8 9.3 171.4 5.53 15 3.6 340 .33 .38 AUG 6.6 4.6 4.3 5.2 4.3 4.6 4.4 5.0 126 639 e!3 ell 626 625 613 69.5 ell 69.2 69.5 elO 69.4 69.0 69.1 e!2 e!3 7.6 6.7 6.5 7.2 6.8 6.1 434.6 14.0 126 4.3 862 .84 .97 SEP 6.1 37 25 9.5 7.5 6.9 6.3 5.5 5.3 5.3 5.5 6.1 6.7 6.1 5.7 5.7 5.3 5.3 5.3 5.3 5.3 5.5 5.7 5.5 5.3 5.3 5.8 8.1 35 20 272.9 9.10 37 5.3 541 .54 .61 , BY WATER YEAR (WY) 26.1 80.2 1980 4.92 1995 FOR 1997 7312 20 212 3 4 924 10 14510 1 16 37 15 5 48.8 179 1981 4.24 1994 WATER YEAR .9 .0 Jan 21 .6 Jul 18 .2 Jul 22 Aug 9 . 61 Aug 9 .20 .29 .3 18.7 78.6 1979 3.59 1994 16.0 104 1979 3.22 1994 WATER 37 117 6 19500 2 2 25900 25 2 26950 2 30 63 13 5 20.1 152 1979 3.97 1994 YEARS 1969 .2 .56 Sep .8 Jul .8 Jul Sep .14 Sep .6 Jul .23 .26 .3 101 1104 1996 3.55 1994 - 1997 1996 1994 10 1996 23 1994 23 1994 10 1996 10 1996 26 1994 e Estimated RIO GRANDE DE MANATI BASIN 50035000 RIO GRANDE DE MANATI AT CIALES, PR 121 LOCATION.--Lat 18°19'26", long 66°27'36", Hydrologic Unit 21010001, on left bank, 1.6 mi (2.6 km) upstream from Hwy 145 bridge, 0.8 mi (1.3 km) downstream from Quebrada Saliente, 0.9 mi (1.4 km) upstream from Quebrada Cojo Vales, and 1.2 mi (1.9 km) southeast of Ciales. DRAINAGE AREA.--128 mi' (332 km'), excludes 6.0 mi' (15.5 km'), the runoff from which is diverted through El Guineo and de Matrullas reservoirs. PERIOD OF RECORD.--September 1946 to September 1953, May 1956 to December 1957 (unpublished, available in files of Caribbean District Office and in the National Water Data Storage and Retrieval System, Washington, D.C.); February 1959 to September 1960 (monthly discharge measurements only); October 1960 to current year. Equivalent record from January 1971 to December 1972 published as 50035200 Rio Grande de Manati at Highway 145 at Ciales at site 1.6 mi (2.6 km) downstream, drainage area 132 mi 2 (342 km'). GAGE.--Water-stage recorder. Elevation of gage is 140 ft (43 m), from topographic map. Prior to Apr. 1, 1962, staff gage, read twice daily, at site 100 ft (30 m) upstream at same datum. January 1971 to December 1972 at site 1.6 mi (2.6 km) downstream at different datum. REMARKS.—Records fair except those for estimated daily discharges, which are poor, satellite telemetry at station. Gage-height and precipitation EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate gage heights of major floods, pointed out by local residents are as follows: August 1899, 50 ft (15 m), September 1928, 36 ft (11 m), and September 1932, 34 ft (10 m) at site 1.6 mi (2.6 km) upstream. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC MAR APR MAY JUN AUG SEP 1 146 182 2 139 161 3 192 148 4 191 150 5 146 142 6 180 143 7 199 142 8 150 133 9 139 146 10 133 171 11 130 266 12 123 261 13 121 194 14 124 161 15 122 142 16 127 148 17 134 193 18 170 515 19 127 518 20 161 334 21 351 357 22 217 420 23 151 505 24 139 598 25 122 635 26 534 367 27 655 275 28 379 276 29 370 288 30 436 433 31 243 —— TOTAL 6551 8404 MEAN 211 280 MAX 655 635 MIN 121 133 AC-FT 12990 16670 CFSM 1.65 2.19 IN. 1.90 2.44 STATISTICS OF MONTHLY MEAN MEAN 425 341 MAX 2422 1006 (WY) 1971 1971 MIN 91.9 34.7 (WY) 1994 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 491 332 263 232 213 189 181 178 172 640 1200 476 315 258 247 303 247 217 187 172 179 180 171 158 151 149 176 165 235 253 211 8541 276 1200 149 16940 2.15 2.48 DATA 256 1296 1966 29.7 1995 185 171 650 446 269 205 170 157 189 258 172 169 e!60 e200 e240 e!70 e!55 e!45 e!60 eSOO e2500 e4200 elSOO ellOO e900 e550 e400 e340 e300 e260 e240 17061 550 4200 145 33840 4.30 4.96 FOR WATER 195 679 1952 26.2 1995 e230 e250 e220 e200 e!90 e!90 e!80 e!70 e!70 e!70 el55 elSO e!49 e!49 e!40 e!35 e!35 e!35 e!40 e!40 e!45 el55 e!32 e!30 e!30 e!25 el!8 112 ___ ___ 4445 159 250 112 8820 1.24 1.29 YEARS 1946 168 1394 1950 41.6 1957 el!3 e!08 e!23 e!27 e!39 e!34 ellO el!7 el!9 ellO e!06 e96 e98 e98 e94 e92 e90 e90 e92 e87 e80 e82 e76 e77 e78 e77 e!22 e!39 e!41 e365 e!75 3555 115 365 76 7050 .90 1.03 - 1997 137 477 1969 29.7 1994 FOR 1996 CALENDAR YEAR 93630 256 26400 58 60 185700 2. 27. 391 123 68 Sep 10 May 6 May 2 00 21 el!6 e96 ellO elOO e93 e86 e82 e80 e76 e74 e71 e73 e70 e67 e65 e62 e55 50 48 47 72 97 76 68 63 61 61 62 59 56 ___ 2196 73.2 116 47 4360 .57 .64 56 99 119 72 64 60 59 54 54 61 64 56 53 51 50 50 52 53 48 46 45 52 52 177 317 199 134 76 66 81 59 2479 80.0 317 45 4920 .62 .72 55 51 48 e48 e61 e50 e45 e46 e45 e43 e45 e45 e43 e41 e41 e39 e37 e39 47 46 41 35 33 31 36 34 34 43 50 97 —— 1349 45.0 97 31 2680 .35 .39 123 65 47 39 35 36 38 66 49 39 36 34 35 35 35 40 37 37 48 60 89 61 44 36 31 e29 e27 e26 e24 e24 e60 1385 44.7 123 24 2750 .35 .40 e200 e75 e40 e28 e28 24 22 22 369 208 73 50 254 232 138 62 98 141 67 64 73 47 44 39 49 39 31 97 108 53 41 2816 90.8 369 22 5590 .71 .82 38 92 195 73 51 46 41 37 38 38 32 33 42 45 41 38 34 32 30 29 34 40 57 41 54 58 52 65 166 158 1730 57.7 195 29 3430 .45 .50 , BY WATER YEAR (WY) 256 1174 1969 28.5 1984 FOR 1997 60512 166 4200 22 28 e 9800 unknown 21 120000 1 17 308 110 37 414 2293 1985 29.6 1994 WATER YEAR Jan 22 Aug 7 JUl 24 Jan 22 Jan 22 Aug 8 .30 .59 151 458 1979 17.8 1994 105 438 1979 14.1 1994 WATER 242 520 47 42700 8 9 128000 25 8 175500 1 25 438 113 51 148 1212 1979 27.0 1994 YEARS 1946 - .3 May 18 .5 JUl 28 .5 Jul 24 Sep 10 .20 Sep 10 .5 Jul 27 .89 .72 299 1295 1996 23.9 1994 1997 1971 1994 1985 1994 1994 1996 1996 1994 e Estimated 122 RIO GRANDE DE MANATI BASIN 50035500 RIO GRANDE DE MANATI AT HIGHWAY 149 AT CIALES, RP WATER-QUALITY RECORDS LOCATION.—Lat 18°20'46", long 66°28'06", at bridge on Highway 149, about 800 ft (244 m) upstream from confluence with Rio Cialitos, 0.5 mi (0.8 km) north of Ciales plaza. DRAINAGE AREA.—136 mi 2 (352 km2 ) this excludes the 6 mi 2 (15.5 km2 ) upstream from Lago El Guineo and Lago de Matrullas, flow from which is diverted to Rio Jacaguas. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 21... FEB 1997 20... JUN 04... AUG 28... TIME 0935 1100 1015 1330 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) TEMPER- ATURE WATER (DEG C) (00010) TUR- BID- ITY (NTU) (00076) OXYGEN, DIS- SOLVED (MG/L) (00300) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 157 191 59 113 226 257 272 243 7.2 7.0 8.1 7.7 27.0 21.5 29.5 29.0 2.0 0.60 1.9 3.3 7.2 8.6 8.4 8.6 88 94 111 111 K1100 310 K1300 580 280 240 410 420 DATE OCT 1996 21... FEB 1997 20... JUN 04... AUG 28... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT PET FIELD MG/L AS CAC03 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS S04) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 85 110 98 22 27 26 7.3 9.5 8.2 13 13 0.5 0.6 0.6 2.2 2.4 2.2 74 100 110 100 <0.5 <0.5 7.9 10 10 11 15 12 OCT 1996 21... FEB 1997 20... JUN 04... AUG 28. .. FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.10 21 0.15 0.15 27 27 127 170 158 53.8 27.2 48.2 0.480 0.010 0.500 0.010 0.310 <0.010 0.090 <0.010 NITRO- NITRO- NITRO- GEN, GEN, GEN, N02+N03 AMMONIA ORGANIC TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L AS N) AS N) AS N) (00630) (00610) (00605) 0.490 0.050 0.37 0.510 0.030 <0.20 0.320 0.040 0.23 0.100 0.020 0.25 DATE NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) OCT 1996 21... 0.41 FEB 1997 20... <0.20 JUN 04... 0.27 AUG 28... 0.28 K = non- ideal count 0.90 0.64 0.59 0.38 4.0 2.8 2.6 1.7 0.060 0.030 0.040 0.260 <100 <100 20 30 19 RIO GRANDE DE MANATI BASIN 50035500 RIO GRANDE DE MANATI AT HIGHWAY 149 AT CIALES, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 123 DATE IRON, TOTAL RECOV- ERABLE (UQ/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UQ/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 21... FEB 1997 20... JUN 04... AUO 28... 300 200 50 <0.10 56 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 <0.01 124 RIO GRANDE DE MANATI BASIN 50035950 RIO CIALITOS AT HIGHWAY 649 AT CIALES, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°20'18", long 66°28'28", 100 ft (30 m) upstream from bridge on Highway 649, upstream from mouth, and about 0.4 mi (0.6 km) west of Ciales plaza. DRAINAGE AREA.--17.0 mi* (44.0 km*). PERIOD OF RECORD.--Water years 1969-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 0.7 mi (1.1 km) DATE OCT 1996 21... FEE 1997 13... jtm 04... SEP 10... OCT 21 FEB 13 JUN 04 SEP 10 OCT 21 FEB 13 JUN 04 SEP 10 OCT 21 FEB 13 JUN 04 SEP 10 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1045 17 238 7.8 25.5 0.60 8.6 103 <10 K1600 3500 1135 34 233 6.6 22.0 0.50 9.1 102 <10 K900 310 1300 9.6 247 8.1 28.5 2.0 8.1 105 <10 K80 K120 1510 9.5 237 8.5 30.0 2.8 7.3 97 <10 300 270 ALKA- HARD- MAGNE- SODIUM POT AS- LINITY CHLO- DATE 1996 ... 1997 ... ... ... DATE 1996 ... 1997 ... DATE 1996 1997 . . . NESS TOTAL (MG/L AS CACO3) (00900) 92 -- 96 93 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.11 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.32 <0.20 <0.20 0.22 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 -- 27 27 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 29 -- 31 27 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.96 1.0 0.56 0.47 SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.6 -- 7.0 6.6 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 151 -- 156 145 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.2 4.5 2.5 2.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 11 -- 11 11 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.16 -- 4.05 3.70 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.050 0.050 0.030 AD- SORP- TION RATIO (00931) 0.5 -- 0.5 0.5 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 4 <1 <1 1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 -- 2.0 1.7 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.630 0.940 0.360 0.250 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 100 97 100 93 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 10 -- 20 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 "" NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.640 0.940 0.370 0.260 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 5.9 -- 6.5 5.5 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 <0.010 0.030 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 — 12 11 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.30 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- 11 — K « non-ideal count RIO GRANDE DE MANATI BASIN 50035950 RIO CIALITOS AT HIGHWAY 649 AT CIALES, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 125 IRON, TOTAL RECOV- ERABLE (OG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (OG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (OG/L AS HN) (01055) MERCURY TOTAL RECOV- ERABLE (OG/L AS HG) (71900) SELE- NIUM, TOTAL (OG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (OG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (OG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (OG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 21... FEB 1997 13... JON 04... SEP 10... 150 150 <1 <1 20 22 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 <0.01 126 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR LOCATION.—Lat 18°25'52", long 66°31'37", Hydrologic Unit 21010002, at bridge on Highway 2, and 2.3 mi (3.7 km) west of Manati. DRAINAGE AREA.—197 mi 2 (510 tan*), approximately, of which about 38 mi> (98 km 1 ) is partly or entirely noncontributing, excludes 6.0 mi* (15.5 km1 ) upstream from Lago El Guineo and Lago de Matrullas. WATER-DISCHARGE RECORDS PERIOD OF RECORD.—1963-68 (annual maximum discharge only), February 1970 to current year. REVISED RECORDS.—WRD PR-86-1: 1970-71 (M), 1975, 1979, 1982-85 (P). GAGE.—Water-stage recorder. Elevation of gage is 14 ft (4 m), from topographic map. Prior to 1968 crest-stage gage at same site and datum 3.57 ft (1.09 m) lower. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. Possible water extraction about 500 ft (152.4 m) upstream of gage by unknown source affecting low flow. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate gage heights to gage datum of major floods, pointed out by local residents, are as follows: Sept. 13, 1928, 36.6 ft (11.16 m), Sept. 27, 1932, 36.3 ft (11.06 m), and Aug. 4, 1945, 34.3 ft (10.45 m). DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV JAN FEB MAR APR JUL AUG 1 231 274 2 220 224 3 229 192 4 345 181 5 248 180 6 246 176 7 285 167 8 224 170 9 201 169 10 189 189 11 183 252 12 176 259 13 172 309 14 183 204 15 209 183 16 184 165 17 165 189 18 218 390 19 176 978 20 175 494 21 268 450 22 442 689 23 216 840 24 190 855 25 165 1190 26 225 615 27 1390 453 28 488 410 29 561 419 30 617 451 31 360 TOTAL 9181 11717 MEAN 296 391 MAX 1390 1190 MIN 165 165 AC -FT 18210 23240 CFSM 1.50 1.98 IN. 1.73 2.21 735 463 372 326 299 270 251 236 224 216 1690 1270 539 369 323 391 354 292 264 243 241 259 232 220 212 208 286 224 246 340 259 11854 382 1690 208 23510 1.94 2.24 233 221 1150 1310 483 331 276 248 236 221 211 205 200 243 300 216 196 186 205 513 4560 6880 2250 1710 1420 867 630 519 470 400 367 27257 879 6880 186 54060 4.46 5.15 349 386 330 305 295 290 268 259 257 255 238 233 229 227 217 212 209 207 215 216 224 239 206 203 200 192 190 178 __. ___ —— 6829 244 386 178 13550 1.24 1.29 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1970 MEAN 722 536 MAX 2958 1803 (WY) 1971 1971 MIN 154 71.0 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 361 1498 1971 71.8 1995 FOR 270 879 1997 59.1 1995 202 444 1988 72.0 1994 172 173 184 191 185 212 180 177 184 174 168 161 159 156 152 151 149 148 150 150 144 140 138 136 134 136 138 142 207 302 181 5174 167 302 134 10260 .85 .98 - 1997 185 521 1972 56.2 1994 1996 CALENDAR YEAR 153686 420 42000 70 74 304800 2.13 29.02 522 178 95 Sep 10 Jul 6 Jul 1 153 141 151 151 142 136 130 127 125 123 121 120 119 116 112 110 107 106 103 101 108 127 115 105 99 98 97 96 98 94 —— 3531 118 153 94 7000 .60 .67 , BY WATER 353 1037 1993 49.9 1995 93 e96 172 115 94 97 94 87 85 92 105 91 86 81 79 78 78 78 76 71 71 73 81 142 258 384 212 131 119 114 105 3538 114 384 71 7020 .58 .67 YEAR (WY) 654 3178 1985 93.7 1989 96 94 88 82 77 72 67 67 67 66 64 65 65 63 61 62 60 58 66 72 69 64 62 58 61 64 61 62 70 91 —— 2074 69.1 96 58 4110 .35 .39 230 747 1987 63.8 1994 FOR 1997 WATER YEAR 91051 249 6880 50 54 13400 28.58 51 180600 1.27 17.19 428 156 62 Jan 22 Jul 29 Jul 24 Jan 21 Jan 21 Sep 20 121 94 75 62 55 52 55 61 77 59 54 e54 e55 e55 e54 e62 e58 e58 e76 e94 e!40 e94 e72 e56 54 60 55 54 50 51 95 2112 68.1 140 50 4190 .35 .40 155 577 1979 53.0 1994 WATER 364 756 96. 55900 31 33 487 145 81 70 71 60 54 51 203 695 181 120 145 527 260 143 117 293 163 114 146 105 93 86 84 84 73 85 165 116 87 5104 165 695 51 10120 .84 .96 210 1644 1979 67.9 1984 YEARS 1970 - 5 May 18 Jan 24 Jul 23 Not determined Sep 10 36. 28 263800 1. 25. 633 166 84 39 Sep 10 Jan 23 85 11 77 72 266 149 107 90 81 73 74 71 65 61 69 88 69 63 59 57 55 54 56 59 70 e64 e86 e90 e82 e90 e96 287 —— 2680 89.3 287 54 5320 .45 .51 509 2506 1996 67.4 1994 1997 1971 1994 1985 1995 1994 1996 1996 1995 e Estimated RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR—Continued WATER-QUALITY RECORDS 127 PERIOD OF RECORD.—Water years 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 JUN 03 AUG DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. JATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) L996 1050 481 230 7.0 24.0 63 7.2 84 <10 K6500 5400 L997 1010 E199 220 7.0 25.0 5.2 7.5 88 <10 K9100 750 0945 88 334 7.5 28.5 6.0 6.8 87 <10 K7600 640 1125 70 332 7.6 28.5 10 6.6 85 <10 3400 540 ALKA- NOV HARD- NESS TOTAL (MG/L DATE AS CACO3) (00900) 1996 21... 89 FEB 26 JUN 03 AUG 28 NOV 21 FEB 26 JUN 03 AUG 28 NOV 21 FEB 26 JUN 03 AUG 1997 ... 140 . .. 140 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 ... 0.10 1997 ... 0.13 . .. 0.14 NITRO- GEN, AM- MONIA + ORGANIC TOTAL DATE (MG/L AS N) (00625) 1996 0.41 1997 0.28 0.56 28... 0.41 K m E « non-ideal count estimated CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 25 -- 41 43 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 21 -- 20 20 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.5 1.0 1.3 1.2 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.4 — 8.6 7.2 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 138 -- 192 182 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 6.6 4.4 5.8 5.3 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 9.6 — 11 11 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 179 -- 45.8 34.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.140 0.060 0.080 0.150 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- 0.4 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 60 12 15 20 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 -- 2.2 2.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 0.700 0.730 0.770 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 90 130 140 130 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.030 0.020 0.020 0.023 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 30 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.10 0.710 0.750 0.790 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 8.2 — 10 9.2 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.060 0.050 0.040 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 4 — 1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 -- 15 12 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.35 0.23 0.52 0.37 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- 11 — 128 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 21... FEB 1997 26... JUN 03... AUG 28... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) ;01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 3000 540 <1 160 87 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <0.01 <0.01 129 LACUNA TORTUGUERO BASIN 50038200 LAGONA TORTUOUERO OUTLET NEAR VEGA BAJA, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°28'29", long 66°26'50", at bridge on Highway 686, 4.2 mi (6.8 km) northeast of 4.4 mi (7.1 km) northwest of Vega Baja plaza. DRAINAGE AREA.—Indeterminate. PERIOD OF RECORD.—Water years 1964-66, 1969-71, 1974 to current year. Manati, and DATE NOV 1996 06... FEE 1997 18... MAY 16... SEP 04... TIME 1115 0815 1045 0950 WATER-QUA SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 1130 750 920 1140 LITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PH OXYGEN, OXYGEN COLI- WATER DIS- DEMAND, FORM, WHOLE FIELD (STAND- ARD UNITS) (00400) 6.7 7.0 7.8 7.7 TEMPER- ATURE WATER (DEG C) (00010) 28.5 25.0 29.0 30.5 OXYGEN, DIS- SOLVED (MG/L) (00300) 4.1 4.6 3.6 5.2 SOLVED (PER- CENT SATUR- ATION) (00301) 50 54 46 69 CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 20 14 31 28 FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K660 220 220 420 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 220 200 2700 810 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 150 140 120 100 DATE NOV 1996 06... FEB 1997 18... MAY 16... SEP 04... SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 2 <1 4 6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.230 0.580 0.100 0.150 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.020 <0.010 0.014 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.240 0.590 0.110 0.170 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.550 0.120 0.180 0.170 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.74 0.76 1.1 1.2 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.3 0.88 1.2 1.4 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.5 1.5 1.4 1.5 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 6.8 6.5 6.0 6.7 DATE NOV 1996 06... FEB 1997 18... MAY 16... SEP 04... PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 0.030 <0.020 <0.020 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 80 — 60 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 12 — IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 70 — 100 — MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) <10 — 11 — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) <10 -- <10 — CYANIDE TOTAL (MG/L AS CN) (00720) <0.010 -- <0.010 — PHENOLS TOTAL (UG/L) (32730) 1 — <1 -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 0.03 -- 0.07 — K - non-ideal count 130 THIS PAGE WAS LEFT BLANK INTENTIONALLY 131 ATLANTIC OCEAN Drainage boundaries in<jetermmat« Jrrrone I .—' igin«ou* and . stdim«ntory roch* Rto EXPLANATION 038320 SURFACE-WATER STATION AND NUMBER 0397 QUALITY-OF-WATER STATION AND NUMBER 213 WELL AND WELL NUMBER 01 23456 KILOMETERS 1234 MiLES Figure 16.-Rio Cibuco basin. 132 RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR LOCATION.—Lat 18°21'13", long 66°20'07", Hydrologic Unit 21010001, on right bank, 150 ft (46 m) downstream from junction with Rio Corozal, and 1.4 mi (2.3 km) northwest of Corozal. DRAINAGE AREA.—15.1 mi 2 (39.1 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—May 1969 to current year. GAGE.—water-stage recorder. Elevation of gage is 195 ft (59 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. Daily discharge affected by sewage treatment plant about 0.6 mi (1.0 km) upstream from station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV JAN FEB JUL AUG SEP 1 42 35 2 48 27 3 56 24 4 47 22 5 84 25 6 76 25 7 57 26 8 48 20 9 45 23 10 46 49 11 47 34 12 44 78 13 57 128 14 57 62 15 45 39 16 39 31 17 34 33 18 33 53 19 31 55 20 35 64 21 32 50 22 32 129 23 41 97 24 34 234 25 43 117 26 255 59 27 83 42 28 30 56 29 129 37 30 47 129 31 40 TOTAL 1737 1803 MEAN 56.0 60.1 MAX 255 234 MIN 30 20 AC-FT 3450 3580 CFSM 3.71 3.98 IN. 4.28 4.44 STATISTICS OF MONTHLY MEAN MEAN 41.1 47.8 MAX 135 155 (WY) 1991 1971 MIN 8.05 8.15 (WY) 1979 1974 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 63 49 41 36 31 31 30 28 26 28 164 54 35 34 82 69 43 33 30 e27 e28 e28 e26 e27 e26 55 e85 e52 e69 e94 e46 1470 47.4 164 26 2920 3.14 3.62 e36 e48 e49 e47 e44 e31 e29 e27 e27 e25 e25 e23 e23 e24 e23 e22 e20 e21 e47 e31 e200 e380 e!40 elSO e94 e64 e52 e46 38 36 36 1858 59.9 380 20 3690 3.97 4.58 DATA FOR WATER 35.5 169 1971 4.14 1995 FOR 25.3 69.6 1992 6.93 1995 33 32 30 29 26 31 31 36 30 28 28 29 29 27 25 25 26 27 29 27 58 33 25 30 26 23 20 19 --- 812 29.0 58 19 1610 1.92 2.00 YEARS 1969 21.2 51.3 1988 7.75 1994 18 21 27 32 33 24 23 42 29 23 18 18 19 18 16 16 16 18 17 16 14 14 12 12 11 13 12 13 12 11 12 580 18.7 42 11 1150 1.24 1.43 - 1997 21.4 65.1 1981 4.36 1984 1996 CALENDAR YEAR 15064. 41. 3070 3. 4. 29880 2. 37. 79 17 6. 2 2 Sep 10 2 Jul 23 9 Jul 17 73 11 0 11 11 13 15 12 10 9.6 8.8 10 10 11 11 9.5 10 9.0 9.0 9.2 9.3 9.2 12 14 13 10 9.0 8.5 8.9 11 9.2 7.9 7.9 309.0 10.3 15 7.9 613 .68 .76 , BY WATER 32.6 111 1973 3.32 1984 7.4 7.5 7.3 8.5 6.6 6.6 6.6 6.6 6.5 6.8 5.7 5.7 6.6 5.8 6.0 8.3 7.5 7.1 6.2 5.4 6.9 6.9 9.8 63 30 53 22 11 9.1 7.7 6.5 360.6 11.6 63 5.4 715 .77 .89 YEAR (WY) 44.1 157 1986 3.20 1977 6.3 7.1 7.0 6.7 6.7 6.5 e6.1 e5.8 e5.6 e5.6 e5.4 e5.4 e5.2 e4.7 e4.5 e4.5 e4.3 e4.0 8.6 8.2 6.2 5.7 6.8 8.9 8.1 6.7 6.9 5.3 5.1 4.6 —— 182.5 6.08 8.9 4.0 362 .40 .45 14.5 44.4 1987 1.63 1994 FOR 1997 WATER YEAR 9775.8 26.8 380 2.6 3.1 6930 15.61 19390 1.77 24.08 55 15 4.5 Jan 22 Aug 7 Aug 3 Jan 21 Jan 21 7.4 4.9 4.3 4.5 4.3 5.8 5.8 14 9.6 5.2 5.0 4.4 4.3 4.2 5.2 5.0 4.4 5.3 9.4 9.5 8.1 5.0 5.3 4.1 7.2 6.1 3.9 3.6 3.1 3.8 3.9 176.6 5.70 14 3.1 350 .38 .44 11.8 34.6 1979 2.19 1994 4.3 3.4 2.9 4.0 3.3 3.4 2.6 2.6 2.8 2.9 8.9 3.9 3.4 5.8 8.9 6.8 16 18 5.8 4.5 4.1 4.9 5.7 7.0 7.1 4.3 5.2 5.5 33 12 9.7 212.7 6.86 33 2.6 422 .45 .52 16.6 50.8 1979 3.44 1978 WATER YEARS 1969 28.8 56.5 7.47 3070 .91 1.2 20400 22.35 20870 1.91 25.92 50 13 5.2 Sep Jul Jun Nov Nov 6.2 5.6 4.9 5.1 4.5 4.4 4.3 4.2 20 10 4.5 4.5 15 13 8.4 5.3 4.4 4.1 3.9 3.7 7.5 7.2 12 8.2 45 e20 e!3 9.8 7.5 8.2 —— 274.4 9.15 45 3.7 544 .61 .68 32.5 191 1996 3.88 1994 - 1997 1971 1994 10 1996 17 1994 21 1994 9 1995 9 1995 e Estimated RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Wat«r y*ar> 1969-76, 1979 to currant year. 133 HATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARQE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 28... 0810 26 309 7.1 23.5 5.6 7.2 83 <10 K890 600 FEB 1997 26... 1430 22 395 7.1 25.0 1.3 7.7 91 <10 >60000 1000 MAY 14... 1140 6.9 387 8.0 27.0 1.7 8.3 105 <10 K1100 380 SEP 08... 0915 4.4 499 7.8 27.5 1.0 6.6 84 <10 K720 470 ALKA- DATE OCT 1996 28... FEB 1997 26... MAY 14... SEP 08... DATE OCT 1996 28... FEB 1997 26... MAY 14... SEP 08... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 120 -- 140 140 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.12 0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 29 -- 36 33 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 25 -- 33 34 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 11 — 12 12 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 189 — 225 210 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 14 -- 21 22 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 13.1 — 4.16 2.49 SODIUM AD- SORP- TION RATIO (00931) 0.6 -- 0.8 0.8 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 10 3 4 4 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.0 — 3.7 3.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.70 2.30 2.70 2.20 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 110 130 130 160 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.030 0.030 0.066 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.70 2.30 2.80 2.20 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 17 — 13 16 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.140 0.060 0.060 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 23 — 28 24 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.27 0.32 0.39 0.30 K - non- ideal count 134 RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 28... PEB 1997 26... MAY 14... SEP 08... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.30 0.47 0.46 0.36 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.0 2.8 3.2 2.6 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 8.8 12 14 12 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.130 0.210 0.340 0.680 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- <1 -- BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 -- CADMIUM MATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 — 1 -- COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 13 — DATE OCT 1996 28... FEB 1997 26... MAY 14... SEP 08... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- ZiENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 480 100 <1 <1 30 50 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.06 RIO CIBUCO BASIN 1 35 50039500 RIO CIBtJCO AT VEGA BAJA, PR LOCATION.--Lat 18°26'53«, long 66°22'29", Hydrologic Unit 21010002, on left bank, at bridge on Bwy 2, 0.6 mi (1.0 km) downstream from Rio Indio, and 0.8 mi (1.3 km) east of Vega Baja. DRAINAGE AREA.—99.1 mi 3 (256.7 km1 ), of which 25.4 mi 3 (65.8 km1 ), does not contribute directly to surface runoff. WATER-DISCHARGE RECORDS PERIOD OF RECORD.—January 1973 to current year. GAGE.—Hater-stage recorder. Datum of gage is 7.79 ft (2.374 m) above mean sea level. REMARKS.—Records fair, except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of Dec. 11, 1965 reached a stage of 26.2 ft (7.99 m), datum unknown, discharge about 28,000 ftVs (793 mVs). DISCHARGE, CUBIC FEET PER SECOND, WATER T DAY OCT NOV 1 88 155 2 83 115 3 77 124 4 117 97 5 133 82 6 126 115 7 75 104 8 63 115 9 72 94 10 65 92 11 58 161 12 54 219 13 50 725 14 86 292 15 54 243 16 60 145 17 44 121 18 42 205 19 e42 264 20 e46 324 21 e42 207 22 e42 656 23 e54 871 24 e45 676 25 e56 759 26 e330 335 27 e!20 245 28 e50 256 29 e200 250 30 e!80 423 31 163 —— TOTAL 2717 8470 MEAN 87.6 282 MAX 330 871 MIN 42 82 AC-FT 5390 16800 CFSM .88 2.85 IN. 1.02 3.18 STATISTICS OF MONTHLY MEAN MEAN 155 194 MAX 559 523 (WY) 1986 1980 MIN 45.9 40.0 (WY) 1974 1974 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 359 251 202 183 161 143 132 121 116 113 612 270 136 112 151 518 210 152 125 109 121 133 103 172 134 113 543 230 301 337 223 6586 212 612 103 13060 2.14 2.47 JAN 165 176 291 494 245 208 149 131 117 108 100 95 87 93 112 80 72 67 89 211 1250 2270 815 894 544 382 308 284 247 217 200 10501 339 2270 67 20830 3.42 3.94 DAILY FEB 188 184 161 151 173 144 139 131 153 129 110 114 134 107 102 92 94 86 103 97 225 217 125 128 125 90 80 70 —— 3652 130 225 70 7240 1.32 1.37 DATA FOR WATER YEARS 1973 172 1316 1982 25.1 1995 FOR 103 339 1997 30.2 1995 88.8 190 1988 27.3 1994 BAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN VALUES MAR 64 69 86 134 139 129 85 109 114 83 78 75 73 70 68 66 64 64 64 62 60 54 56 54 45 44 45 63 84 55 47 2303 74.3 139 44 4570 .75 .86 - 1997 83.6 339 1990 20.5 1994 1996 CALENDAR YEAR 55145 151 12800 18 20 109400 1.52 20.70 252 63 28 Sep 10 Jul 5 Jun 30 APR 47 45 52 56 60 58 52 50 50 49 47 45 42 41 39 36 35 36 36 35 45 39 41 35 33 35 34 35 32 32 —— 1272 42.4 60 32 2520 .43 .48 MAY 31 31 30 33 30 31 29 29 29 29 29 29 29 30 29 28 27 24 23 24 25 26 26 133 249 274 224 95 51 46 40 1763 56.9 274 23 3500 .57 .66 JUN 40 36 37 34 31 29 28 27 26 26 25 25 24 22 21 21 20 18 m28 36 25 24 26 34 45 28 25 23 22 22 —— 828 27.6 45 18 1640 .28 .31 JUL 26 27 21 19 19 22 22 25 39 27 22 20 20 20 21 28 31 31 44 46 47 39 28 *[26 25 40 27 23 22 22 36 865 27.9 47 19 1720 .28 .32 AUG 30 28 25 29 29 26 24 •20 •21 •18 •41 •22 •21 •30 •40 •31 •76 e82 48 25 25 •23 •26 •33 •33 •21 •24 •25 •150 •54 •45 1125 36.3 150 18 2230 .37 .42 SEP •28 •26 •22 e24 •21 e20 •20 •20 •94 •40 •21 •21 •70 •60 •38 •24 •22 •21 •20 •19 •35 •34 •54 •38 •210 •110 •60 •45 •35 e38 —— 1290 43.0 210 19 2560 .43 .48 , BY WATER YEAR (WY) 150 667 1987 16.2 1984 FOR 1997 41372 113 2270 18 22 2730 14 82060 1 15 244 54 23 190 655 1985 24.7 1977 WATER YEAR Jan 22 Jun 18 Jun 12 Jan 22 .66 Jan 22 .14 .53 70.3 239 1987 12.5 1994 51.4 162 1979 14.0 1994 78.6 461 1979 21.2 1978 WATER YEARS 1973 - 122 236 38.5 14600 7.2 8.1 34000 19.10 7.2 88060 1.23 16.67 225 58 22 Dec 13 May 3 • Apr 28 Apr 12 Apr 12 May 2 141 690 1996 26.7 1994 1997 1982 1994 1981 1995 1995 1987 1987 1995 e Estimated 136 RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEGA BAJA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1972 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. 1ATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1000 99 333 7.2 24.5 63 6.3 74 <10 K7700 K20000 .997 1140 85 448 6.8 23.5 18 7.9 91 <10 K1000 210 1445 28 470 8.0 27.5 3.0 6.6 83 <10 560 330 1200 21 479 7.8 29.5 2.5 5.2 68 <10 K1700 560 ALKA- DATE OCT 1996 28... FEB 1997 18... MAY 16... SEP 04... DATE OCT 1996 28... FEB 1997 18... MAY 16... SEP 04... DATE OCT 1996 28... FEB 1997 18... MAY 16... SEP 04... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 130 -- 200 190 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.14 0.11 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.71 <0.20 0.32 1.4 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 41 — 65 61 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 16 -- 20 16 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.1 1.7 2.2 3.5 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.0 -- 10 9.2 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 188 — 268 257 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 9.2 7.6 9.6 15 SODIUM, DIS- SOLVED (MG/L AS NA) (00.930) 11 -- 18 19 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 50.4 — 20.4 14.4 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.190 0.080 0.160 0.170 SODIUM AD- SORP- TION RATIO (00931) 0.4 — 0.6 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 84 <1 5 3 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.4 -- 2.7 3.1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.30 1.50 1.80 2.10 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 130 180 190 180 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.040 0.020 0.020 0.019 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- <10 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.40 1.60 1.80 2.10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 14 — 13 13 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.090 0.030 0.030 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 5 — 3 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 17 -- 26 28 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.62 <0.20 0.29 1.4 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 -- K - non- ideal count RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEQA BAJA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 137 IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) OCT 1996 28... FEB 1997 18... MAY 16... 2800 690 <1 130 110 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 <0.01 04... 138 THIS PAGE WAS LEFT BLANK INTENTIONALLY 139 SAN JUAN igneous and sedimentary rocfc* 8AYAMON / \ i Limestone x igneous ond \ s*dim*nfory rocks v / \ I J fifffrtSO • tf<? Corner EXPLANATION A 0460 SURFACE-WATER STATION ^ AND NUMBER V 0430 QUAUTY-OF-WATER STATION AND NUMBER 0399 V QUAUTY-OF-WATER PARTIAL 216 RECORD STATION AND NUMBER A 0438 DAILY SEDIMENT STATION AND -^ NUMBER 0 039990 WELL AND WELL NUMBER • 0450 LAKE-ELEVATION STATION AND ™ NUMBER "\U^..N -^" ) iftfl* iN.flaO) D0»'n"\^\^ j "V. 0 1' 2 3 4 5 6 KILOMETERS \ I i i J I i Rc-aman-V /> I I I ! I 'j,a,in '"**&,/' ^ 01234 MILES ^ Figure 17.--Rio de la Plata basin. 140 RIO DE LA PLATA BASIN 50039990 LAGO CARITE AT GATE TOWER NEAR CAYEY, PR LOCATION.--Lat 18°03'46", long 66°05'58", Hydrologic Unit 21010005, on top of a concrete tower at diversion tunnel on Carite Reservoir, 0.7 mi (1.1 km) northwest from Escuela Carite Chino, 1.2 mi (1.9 km) northeast from Central Hidroelectrica de Carite Num. 1 and 1.8 mi (2.9 km) northeast from Escuela Segunda Unidad. DRAINAGE AREA.--8.20 mi* (21.24 km2 ). ELEVATION RECORDS PERIOD OF RECORD.--Hay 1989 to current year. Prior to October 1994, published as Lago Carite at Gate Tower. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.--Lago Carite Dam was completed in 1913. The operation of the reservoir is controlled by the utilization of water to meet the demands for domestic, industrial and agricultural purposes in the Guayama Area. The dam is an earthfill with crest elevation of 1,806 ft (550 m) above mean sea level, with a structural height of 104 ft (32 m) and a lenght of 500 ft (152 m). The dam has a capacity of approximately 11,310 acre-feet (13.9 hm3 ). The Dam is operated by the Puerto Rico Electric and Power Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 1,788.73 ft (545.20 m), Sep. 10, 1996; minimum elevation, 1,761.22 ft (536.81 m), May 28, 1995. EXTREMES FOR CURRENT YEAR.--Maximum elevation 1,782.08 ft (543.18 m), Nov. 12; minimum elevation, 1,768.95 ft (539.18 m), Sep. 21. Capacity Table (based on Data from Puerto Rico Electric Power Authority) Contents, in acre-feet Elevation, in feet Elevation, in feet 1,746 0 1,760 2,471 1,769 4,561 1,775 1,780 1,790 Contents, in acre-feet 6,194 7,704 11,048 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT DEC JUN JUL AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN CAL WTR A A A A 1781.52 1781.54 1781.52 1781.49 1781.54 1781.67 1781.63 1781.56 1781.52 1781.52 1781.55 1781.55 1781.49 1781.53 1781.54 1781.50 1781.40 1781.36 1781.38 1781.48 1781.43 1781.47 1781.48 1781.49 1781.45 1781.45 1781.48 1781.67 1781.36 YR 1996 YR 1997 1781.55 1781.51 1781.50 1781.53 1781.51 1781.51 1781.51 1781.52 1781.50 1781.45 1781.91 1782.08 1781.85 1781.68 1781.59 1781.54 1781.54 1781.50 1781.50 1781.56 1781.88 1781.65 1781.62 1781.54 1781.48 1781.46 1781.44 1781.45 1781.44 1781.44 1782.08 1781.44 MAX 1782. MAX 1782. 1781.46 1781.45 1781.43 1781.41 1781.43 1781.46 1781.42 1781.43 1781.40 1781.38 1781.64 1781.55 1781.50 1781.50 1781.51 1781.45 1781.43 1781.43 1781.43 1781.42 1781.34 1781.37 1781.38 1781.37 1781.38 1781.35 1781.35 1781.34 1781.56 1781.56 1781.50 1781.64 1781.34 84 MIN 08 MIN 1781.47 1781.43 1781.48 1781.39 1781.40 1781.39 1781.34 1781.33 1781.31 1781.29 1781.38 1781.34 1781.34 1781.28 1781.25 1781.30 1781.20 1781.18 1781.18 1781.22 1781.36 1781.53 1781.50 1781.50 1781.49 1781.46 1781.42 1781.43 1781.43 1781.37 1781.38 1781.53 1781.18 1779.31 1768.99 1781.61 1781.56 1781.54 1781.49 1781.51 1781.47 1781.48 1781.44 1781.48 1781.44 1781.41 1781.41 1781.55 1781.57 1781.48 1781.49 1781.40 1781.47 1781.44 1781.44 1781.51 1781.53 1781.56 1781.47 1781.48 1781.57 1781.58 1781.51 ___ ___ ___ 1781.61 1781.40 1781.44 1781.47 1781.44 1781.44 1781.41 1781.38 1781.36 1781.40 1781.40 1781.37 1781.30 1781.32 1781.33 1781.29 1781.35 1781.39 1781.37 1781.39 1781.31 1781.37 1781.32 1781.25 1781.21 1781.25 1781.19 1781.10 1781.11 1781.19 1781.15 1781.12 1781.12 1781.47 1781.10 1780.99 1781.51 1781.48 1781.45 1781.41 1781.33 1781.33 1781.28 1781.28 1781.20 1781.17 1781.13 1781.15 1781.05 1781.04 1781.04 1780.98 1780.95 1780.91 1780.89 1780.70 1780.76 1780.68 1780.66 1780.63 1780.43 1780.29 1780.13 1779.99 1779.87 ___ 1781.51 1779.87 1779.70 1779.65 1779.51 1779.35 1779.25 1779.15 1778.99 1778.88 1778.80 1778.69 1778.58 1778.45 177*. 37 1778.28 1778.17 1778.08 1778.03 1777.91 1777.78 1777.67 1777.53 1777.38 1777.23 1777.13 1776.98 1776.82 1776.78 1776.66 1776.56 1776.46 1776.39 1779.70 1776.39 1776.27 1776.23 1776.30 1776.23 1776.12 1775.97 1775.84 1775.72 1775.57 1775.45 1775.31 1775.18 1775.04 1774.94 1774.81 1774.68 1774.55 1774.40 1774.25 1774.12 1774.01 1773.85 1773.73 1773.59 1773.45 1773.33 1773.21 1773.06 1772.92 1772.78 ___ 1776.30 1772.78 1772.63 1772.50 1772.36 1772.22 1772.11 1772.03 1771.92 1771.81 1771.67 1771.55 1771.40 1771.28 1771.17 1771.04 1770.91 1770.85 1770.75 1770.65 1770.64 1770.73 1770.90 1770.81 1770.72 1770.64 1770.52 1770.45 1770.39 1770.40 1770.29 1770.19 1770.24 1772.63 1770.19 1770.20 1770.14 1770.11 1770.09 1770.04 1770.00 1769.97 1769.94 1769.94 1770.02 1770.02 1770.01 1769.96 1769.85 1769.84 1769.76 1769.73 1769.68 1769.60 1769.51 1769.42 1770.85 1770.88 1771.11 1771.12 1771.09 1771.03 1770.96 1770.93 1770.92 1770.89 1771.12 1769.42 1770.81 1770.77 1770.66 1770.54 1770.45 1770.34 1770.22 1770.13 1770.02 1769.90 1769.78 1769.72 1769.67 1769.59 1769.52 1769.39 1769.32 1769.23 1769.11 1768.99 1769.23 1769.36 1769.46 1769.42 1769.44 1769.54 1769.53 1769.48 1769.47 1769.44 ___ 1770.81 1768.99 A No gage-height record RIO DE LA PLATA BASIN 50043000 RIO DE LA PLATA AT PROYECTO LA PLATA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1958 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 141 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. JATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) L996 1000 55 379 7.8 27.0 1.2 8.0 100 <10 K150 410 L997 1115 19 376 6.9 23.5 1.2 8.7 102 <10 K50 K73 0945 20 393 8.1 27.0 2.4 7.9 101 <10 250 360 1045 77 333 7.8 27.5 2.2 7.0 92 <10 24000 9400 ALKA- DATE OCT 1996 09... FEB 1997 19... MAY 13... SEP 09... DATE OCT 1996 09... FEB 1997 19... MAY 13... SEP 09... DATE OCT 1996 09... FEB 1997 19... MAY 13... SEP 09... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 140 -- 120 110 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.14 0.12 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 0.28 0.48 0.57 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 36 — 30 31 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 20 -- 22 17 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.4 1.7 1.8 1.8 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 -- 12 10 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 265 -- 221 203 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 6.2 7.5 7.9 7.8 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 28 -- 31 29 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 39.6 -- 12.0 42.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.130 0.170 0.320 0.150 SODIUM AD- SORP- TION RATIO (00931) 1 -- 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 2 <1 1 <1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 _- 1 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.4 -- 2.5 2.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.20 1.40 1.30 1.10 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 160 140 130 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.010 0.030 0.054 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 _- 60 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.30 1.40 1.30 1.20 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -_ <1 -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 19 -- 17 18 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.020 0.040 0.090 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 51 -- 29 36 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.26 0.43 0.48 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- 10 — K • non-ideal count 142 RIO DE LA PLATA BASIN 50043000 RIO DE LA PLATA AT PROYECTO LA PLATA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MANGA- DATE IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (OG/L (UG/L TOTAL RECOV- ERABLE (UG/L MERCURY SILVER, ZINC, TOTAL SELE- TOTAL TOTAL RECOV- NIUM, RECOV- RECOV- CYANIDE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (OG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 09... FEE 1997 19... MAY 13... SEP 09... 80 170 <1 <1 20 <0.10 27 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.10 143 RIO DE LA. PLATA BASIN 50043800 RIO BE LA PLATA AT COMERIO, PR LOCATION.--Lat 18e13'23", long 66»13'30", Hydrologic unit 21010005, on right bank 50 ft (15 m) upstream from bridge off Highway 167 in the Town of Comerio, 0.4 mi (0.6 km) southwest of Comerio High School, and 0.2 mi (0.3 km) northeast of Plaza de Comerio. DRAINAGE AREA.--109 mi* (282 km'). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—December 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 604.2 ft (184.160 m) above mean sea level. REMARKS.—Records fair. Filtration plant more or less 1,000 feet upstream from station. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO DAILY MEAN VALUES DAY OCT NOV JAN MAR APR MAY JUN 1997 JtJL AUQ SEP 1 84 65 2 82 67 3 83 67 4 85 62 5 79 64 6 79 60 7 87 57 8 77 58 9 75 61 10 80 65 11 94 217 12 86 409 13 79 489 14 75 252 15 77 186 16 75 153 17 66 134 18 63 184 19 84 199 20 92 215 21 76 212 22 73 445 23 66 293 24 62 193 25 58 151 26 64 99 27 108 82 28 87 88 29 123 84 30 161 93 31 69 —— TOTAL 2549 4804 MEAN 82.2 160 MAX 161 489 MIN 58 57 AC-FT 5060 9530 CFSM .76 1.48 IN. .87 1.65 STATISTICS OF MONTHLY MEAN MEAN 191 96.3 MAX 866 166 (WY) 1991 1993 MIN 40.6 19.0 (WY) 1992 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 129 101 84 72 71 65 62 63 57 55 194 153 73 60 55 51 48 46 41 39 34 35 33 33 35 35 36 35 47 64 98 2004 64.6 194 33 3970 .60 .69 56 41 36 34 32 31 30 31 31 29 30 37 33 30 36 33 31 27 29 45 153 627 249 e!90 el49 el!9 e90 e74 76 72 65 2546 82.1 627 27 5050 .76 .87 DATA FOR WATER 54.4 112 1993 17.1 1995 FOR 144 732 1992 21.3 1995 157 168 107 80 70 67 64 60 60 64 59 57 57 75 71 63 61 56 54 57 71 99 76 80 62 74 103 75 —— 2147 76.7 168 54 4260 .71 .74 YEARS 1989 81.6 247 1989 24.4 1990 66 62 62 63 64 60 54 54 54 51 49 44 44 45 45 48 52 47 41 41 39 38 35 31 30 30 29 40 89 66 39 1512 48.8 89 29 3000 .45 .52 - 1997 41.9 75.7 1989 20.6 1993 1996 CALENDAR YEAR 86395 236 32400 13 15 171400 2. 29. 320 66 21 Sep 10 May 5 May 1 18 62 35 33 344 82 60 51 42 38 36 35 34 34 34 33 32 32 31 30 30 29 29 30 30 29 28 28 29 38 41 40 —— 1397 46.6 344 28 2770 .43 .48 35 34 36 34 33 33 33 33 33 48 52 39 36 36 37 39 46 59 41 35 34 35 48 292 75 47 42 37 33 37 44 1496 48.3 292 33 2970 .44 .51 36 33 32 43 37 30 27 26 24 22 21 20 20 20 21 22 18 e!9 22 19 23 21 18 20 23 20 17 19 18 16 —— 707 23.6 43 16 1400 .22 .24 16 16 15 14 14 14 24 25 19 17 15 15 14 14 13 15 19 35 24 23 56 116 42 28 26 22 21 22 42 32 33 801 25.8 116 13 1590 .24 .27 31 24 19 16 14 12 12 12 12 13 14 13 13 14 14 13 18 20 19 23 15 222 261 54 359 56 28 24 40 24 16 1425 46.0 359 12 2830 .42 .49 14 14 14 12 11 11 11 14 141 31 16 16 20 26 19 18 14 12 12 11 12 23 51 37 32 49 78 31 20 16 —— 786 26.2 141 11 1560 .24 .27 , BY WATER YEAR (WY) 53.3 162 1993 22.3 1991 FOR 1997 22174 60 627 11 12 1750 6 43980 7 107 39 16 90.0 263 1992 19.7 1994 WATER YEAR .8 Jan 22 Sep 5 Sep 1 Aug 22 .19 Aug 22 .56 .60 77.5 213 1996 13.2 1994 97.0 291 1993 10.4 1994 WATER 113 239 35 32400 5 7 127000 29 81770 1 14 159 35 15 75.9 193 1996 12.7 1994 YEARS 1989 - .3 Sep 10 .8 Jun 25 .3 Jul 31 Jan 5 .22 Jan 5 .04 .13 382 1433 1996 26.2 1997 1997 1996 1994 1996 1994 1994 1992 1992 e Estimated 144 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COHERIO, PR—Continued WATER-QUALITY RECORDS PERIOD or RECORDS.-- Water years 1989 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1989 to current year. INSTRUMENTATION.— USD-77 sediment sampler since 1989. Automatic sediment sampler since 1989. REMARKS.—Sediment samples were collected by a local observer on a week basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 8,800 mg/L Jan. 05, 1992; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 950,000 tons (862,000 tonnes) Jan. 05, 1992; Minimum daily mean, 0.04 tons (0.04 tonne) November 28, 1994. EXTREMES FOR WATER YEARS 1997.— SEDIMENT CONCENTRATION: Maximun daily mean, 494 mg/1 May 24, 1997; Minimun daily mean, 1 mg/L April 18, 1997. SEDIMENT LOADS: Maximun daily mean, 611 tons (554 tonnes) January 22, 1997; Minimun daily mean .11 tons (.10 tonnes) April 18, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 84 82 83 85 79 79 87 77 75 80 94 86 79 75 77 75 66 63 84 92 76 73 66 62 58 64 108 87 123 161 69 10 11 11 10 9 8 39 17 7 10 14 18 18 18 16 11 8 6 24 16 6 11 18 19 19 23 57 47 18 83 31 2.3 2.3 2.4 2.2 1.9 1.7 9.5 3.6 1.4 2.0 3.5 4.3 3.9 3.6 3.3 2.3 1.4 1.0 6.3 4.2 1.3 2.2 3.1 3.1 3.0 4.1 17 11 8.8 53 5.8 65 67 67 62 64 60 57 58 61 65 217 409 489 252 186 153 134 184 199 215 212 445 293 193 151 99 82 88 84 93 65 67 67 62 64 60 57 58 61 65 217 409 489 252 186 153 134 184 199 215 212 445 293 193 151 99 82 88 84 93 19 14 10 8 10 11 13 14 21 20 111 228 347 121 51 24 22 64 116 243 375 239 163 168 61 22 45 79 59 42 3.2 2.5 1.8 1.4 1.7 1.9 2.0 2.2 3.6 3.7 228 267 481 85 26 10 8.1 45 65 163 228 329 134 90 26 6.0 9.9 19 13 11 TOTAL 2549 175.5 4804 2268.0 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) DECEMBER 129 101 84 72 71 65 62 63 57 55 194 153 73 60 55 51 48 46 41 39 34 35 33 33 35 35 36 35 47 64 98 2004 38 21 11 6 6 7 7 7 8 8 82 47 30 21 15 11 8 6 5 4 4 5 5 6 7 8 9 12 23 17 19 —— 13 5.6 2.4 1.2 1.2 1.2 1.2 1.2 1.2 1.2 57 22 5.9 3.5 2.3 1.5 1.0 .73 .57 .47 .39 .44 .48 .54 .66 .76 .93 1.1 3.3 2.9 5.9 141.77 RIO DE IA PLATA BASIN 50043800 RIO DE IA PIATA AT COMERIO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 745 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MO/L) (TONS/DAY) (CFS) (MO/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 56 41 36 34 32 31 30 31 31 29 30 37 33 30 36 33 31 27 29 45 153 627 249 e!90 e!49 el!9 e90 e74 76 72 65 8 7 9 10 13 15 18 20 17 14 12 17 10 23 90 20 23 20 15 23 71 338 133 55 23 10 4 3 8 7 5 1.2 .82 .85 .96 1.1 1.2 1.5 1.7 1.4 1.1 .99 1.8 .90 3.2 9.7 1.8 2.0 1.5 1.2 2.9 69 611 95 e22 e7.8 e2.7 e.96 e.61 1.8 1.3 .93 FEBRUARY 157 168 107 80 70 67 64 60 60 64 59 57 57 75 71 63 61 56 54 57 71 99 76 80 62 74 103 75 ___ 56 94 21 19 18 17 15 13 11 11 12 12 12 11 11 11 10 10 12 13 23 51 41 9 5 10 19 12 —— 64 51 6.2 4.0 3.4 3.2 2.6 2.0 1.8 2.0 1.9 1.8 1.8 2.3 2.1 1.8 1.7 1.6 1.7 2.1 4.8 14 8.4 2.1 .84 2.6 5.9 2.4 —— —— CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH TOTAL 2546 850.92 2147 200.04 66 62 62 63 64 60 54 54 54 51 49 44 44 45 45 48 52 47 41 41 39 38 35 31 30 30 29 40 89 66 39 1512 11 11 12 18 22 18 14 12 15 20 22 17 13 11 13 15 18 18 19 19 19 19 21 23 24 23 23 25 55 46 39 2.0 1.9 2.0 3.0 3.8 2.9 2.0 1.7 2.2 2.7 2.9 2.0 1.5 1.3 1.5 2.0 2.5 2.3 2.1 2.1 2.0 2.0 2.0 1.9 1.9 1.9 1.8 3.2 17 8.3 4.1 90.5 e Estimated 146 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CPS) (MG/L) (TONS/DAY) (CPS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 35 33 344 82 60 51 42 38 36 35 34 34 34 33 32 32 31 30 30 29 29 30 30 29 28 28 29 38 41 40 APRIL 31 22 159 50 39 31 24 19 17 18 19 18 15 13 9 4 2 1 3 7 11 11 10 9 11 12 14 19 16 13 —— MAY 2.9 1.9 227 11 6.3 4.2 2.8 2.0 1.6 1.7 1.7 1.7 1.4 1.1 .78 .36 .16 .11 .23 .51 .90 .88 .80 .73 .82 .95 1.1 1.9 1.7 1.4 —— 35 34 36 34 33 33 33 33 33 48 52 39 36 36 37 39 46 59 41 35 34 35 48 292 75 47 42 37 33 37 44 12 11 11 10 11 13 14 13 12 23 29 28 29 37 49 56 45 29 12 13 14 16 95 494 42 34 41 36 32 29 29 1.1 1.0 1.0 .96 1.0 1.1 1.2 1.1 1.0 3.3 4.1 2.9 2.8 3.6 5.0 6.0 5.6 4.7 1.3 1.2 1.3 1.5 25 387 8.9 4.3 4.6 3.6 2.8 2.9 3.4 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 36 33 32 43 37 30 27 26 24 22 21 20 20 20 21 22 18 »19 22 19 23 21 18 20 23 20 17 19 18 16 28 26 20 103 139 93 61 41 28 19 14 13 12 12 18 26 20 18 65 55 47 41 35 22 12 10 8 9 10 9 2.8 2.3 1.8 14 14 7.5 4.4 2.8 1.8 1.1 .80 .72 .67 .64 1.1 1.6 .99 el.l 3.8 2.9 3.0 2.3 1.7 1.2 .78 .54 .38 .46 .47 .39 TOTAL 1397 280.63 1496 495.26 707 78.04 e Estimated RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 147 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 16 16 15 14 14 14 24 25 19 17 15 15 14 14 13 15 19 35 24 23 56 116 42 28 26 22 21 22 42 32 33 801 22174 JULY 8 7 7 6 6 7 12 14 13 11 10 9 8 7 6 7 9 18 13 12 26 61 22 15 14 13 12 11 20 16 16 —— AUGUST .32 .29 .26 .24 .22 .26 .85 .96 .64 .50 .41 .34 .29 .25 .22 .29 .49 1.7 .82 .73 4.0 23 2.6 1.2 1.0 .75 .68 .63 2.7 1.4 1.4 49.44 5540.07 31 24 19 16 14 12 12 12 12 13 14 13 13 14 14 13 18 20 19 23 15 222 261 54 359 56 28 24 40 24 16 1425 15 12 9 8 7 6 6 6 6 7 7 6 6 7 7 7 9 11 10 10 7 109 136 28 183 29 14 12 26 25 28 —— 1.3 .74 .46 .32 .24 .20 .20 .20 .20 .24 .25 .22 .22 .26 .27 .27 .44 .60 .52 .64 .29 370 154 4.2 282 4.8 1.1 1.0 3.3 1.6 1.2 831.28 SEPTEMBER 14 14 14 12 11 11 11 14 141 31 16 16 20 26 19 18 14 12 12 11 12 23 51 37 32 49 78 31 20 16 —— 786 26 21 17 14 14 15 15 13 72 22 15 11 11 17 18 19 18 13 9 7 6 11 26 20 17 25 41 16 11 9 —— —— .97 .78 .63 .47 .44 .45 .43 .47 38 1.8 .66 .46 .64 1.2 .91 .90 .68 .44 .30 .20 .19 1.1 3.6 2.1 1.5 7.4 9.6 1.4 .59 .38 —— 78.69 148 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DATE MAY 1997 24... TIME 0645 DIS- CHARGE, INST. CUBIC PER SECOND (00061) 67 SEDI- MENT, SUS- PENDED (MO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- SED. SUSP. PALL DIAM. SED. SUSP. FALL DIAM. SED. SUSP. PALL DIAM. (T/DAY) (80155) * FINER * FINER * FINER THAN THAN THAN .002 MM .004 MM .008 MM (70326) (70327) (70328) 4230 788 44 56 67 DATE MAY 1997 24... SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. * FINER THAN .250 MM (70333) SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 81 89 99 100 100 100 100 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 149 NOV 13 JAN 23 MAY 24 SEP 09 DATE 1996 ... 1997 ... ... ... TIME 1910 0745 0630 0715 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 555 289 67 248 SEDI- MENT, SUS- PENDED (MG/L) (80154) 699 2370 318 129 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 1050 1850 57 86 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 100 100 100 91 150 RIO DE LA PLATA BASIN 50044000 RIO DE LA PLATA NEAR COMERIO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°14'33", long 66°12'28", at bridge on Highway 156, 0.56 mi (0.9 km) upstream from dam, about 2.0 mi (3.2 km) northeast of Comerio plaza. DRAINAGE AREA.--139 mi 1 (360 tan'), excludes 8.2 mi' (21.1 tan1 ) upstream from Carite Reservoir, the flow of which is diverted to Rio Guamani. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEW- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1230 91 0935 110 1105 36 1100 19 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 160 — 150 140 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 ~ 0.16 0.13 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.23 0.30 0.38 0.30 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 39 — 34 34 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 23 ~ 29 26 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.4 1.5 0.91 0.82 432 424 408 390 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 15 — 16 14 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 256 — 238 227 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 6.0 6.5 4.0 3.6 7.7 7.7 8.1 8.2 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 23 — 25 24 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 63.2 — 23.4 11.8 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.090 0.080 0.080 0.110 28.0 1 22.0 1 28.0 4 29.5 3 SODIUM AD- SORP- TION RATIO (00931) 0.8 — 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 3 <1 3 10 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — 1 __ .0 .2 .3 .1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.9 — 2.3 2.6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 1.20 0.520 0.500 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 __ 7.6 8.2 7.8 9.2 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 180 140 150 140 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.020 0.018 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 — 60 — 95 93 99 123 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.10 1.20 0.530 0.520 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — <10 K8600 K1500 11 <10 <10 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 17 — 15 16 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.070 0.030 0.040 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — 510 380 590 250 470 260 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 28 — 27 26 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.26 0.34 0.26 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — non-ideal count 151 RIO DE LA PLATA BASIN 50044000 RIO DE LA PLATA NEAR COMERIO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS UN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 08... FEE 1997 24... JUN 06... SEP 05... 100 200 <1 <1 30 37 <0.10 <0.10 <1 <1 <1 <1 <0.010 <10 <0.010 <1 <1 0.03 0.03 752 RIO DE LA PLATA BASIN 50044850 RIO GUADIANA NEAR NARANJITO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°18'39", long 66°13'28", at steel-cross-bridge 0.8 mi (1.3 km) northwest of Highway 164, 1.2 mi (1.9 km) upstream from mouth and about 2.0 mi (3.2 km) northeast of Naranjito plaza. DRAINAGE AREA.--4.0 mi 2 (10.3 km2 ). PERIOD OF RECORD.--Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DZS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DZS- DEMAND, FORM, STREP - ZNST. CZFZC WHOLE SOLVED CHEM- FECAL, TOCOCCZ CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. HATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEO C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 0850 8.6 338 7.4 26.0 19 7.2 87 <10 K14000 4900 .997 1145 13 390 7.5 23.0 26 8.0 91 <10 5800 K1800 1000 4.5 385 8.0 27.5 0.32 9.2 116 <10 5000 360 1225 3.4 445 7.9 32.0 0.52 7.3 101 <10 260 330 ALKA- DATE OCT 1996 15... FEB 1997 24... MAY 12... SEP 05... DATE OCT 1996 15... FEB 1997 24... MAY 12... SEP 05... DATE OCT 1996 15... FEB 1997 24... MAY 12... SEP 05... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 140 -- 160 180 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 -- 0.13 0.14 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.31 0.40 <0.20 0.21 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 30 -- 38 43 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 24 -- 27 25 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.0 2.2 1.2 1.6 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 15 -- 16 17 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 204 -- 239 254 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 8.7 9.6 5.3 6.9 SODIUM, Dis- SOLVED (MG/L AS NA) (00930) 16 __ 18 22 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.75 -- 2.91 2.31 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.170 0.140 0.100 0.130 SODIUM AD- SORP- TION RATIO (00931) 0.6 — 0.6 0.7 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 50 37 <1 2 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- 2 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.4 _- 2.6 2.4 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) -- 1.70 1.00 1.30 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 130 130 160 150 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) •eO.010 0.020 0.020 0.031 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- 30 -- SULFIDE TOTAL (MG/L AS S) (00745) 2.6 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.70 1.80 1.00 1.40 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 16 -- 16 26 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.040 0.020 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 4 -- <1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 22 -- 25 29 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.28 0.36 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 -- K » non- ideal count RIO DE LA PLATA BASIN 50044850 RXO GUADXANA NEAR NARANJITO, PR—Continued WATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 15$ DATE OCT 1996 15... FEE 1997 24... MAY 12... SEP 05... IRON, TOTAL RECOV- ERABLE (UO/L AS FB) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 2100 90 160 <0.10 100 <0.10 <1 <1 <1 <1 80 <0.010 <0.010 <1 <0.01 0.02 754 RIO DE LA PLATA BASIN 50045000 LAGO LA PLATA AT DAHSITE NEAR TOA ALTA, PR LOCATION.--Lat 18°20'40", long 66°14'10", Hydrologic Unit 21010005, 2.9 ml (4.7 km) at northeast of Plaza de Naranjito, 2.7 ml (4.3 km) West of Road 167, km 15.3, Buena Vista, Bayamon, 5.2 ml (8.4 km) east of Plaza de Corozal. DRAINAGE AREA.--181 ml 2 (469 km2 ). ELEVATION RECORDS PERIOD OF RECORD.--February 1989 to current year. Prior to October 1994, published as Lago La Plata at Damsite. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.--Lago La Plata first construction phase was completed in 1974 and the second construction phase to provide the spillway with bascule gates was completed in October 1989. The maximum storage is 37,000 ac-ft (45.6 hm3 ) and its purpose is the supply of water for domestic and industrial use. La Plata Dam is a concrete gravity structure located across the Rio de la Plata, the dam has an overall length of 774 ft (236 m) and a maximum height of about 131 ft (40 m). The dam spillway is provided with 6 bascule gates. The spillway crest has a total clear length of 690 ft (210 m), an elevation of 155 ft (47 m). The Dam is owned and operated by Puerto Rico Aqueduct and Sewer Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 170.90 ft (52.09 m), Sept. 10, 1996; minimum elevation, 107.95 ft (32.90 m), Feb. 21, 1995. EXTREMES FOR CURRENT YEAR.--Maximum elevation, 166.90 ft (50.87 m), Feb. 16; minimum elevation, 128.95 ft (39.30 m), Sept. 30. Capacity Table (based on data from Puerto Rico Aqueduct and Sewer Authority) Elevation, in feet 98.43 131.24 154.60 Contents, in acre-feet 2,760 11,360 22,720 Elevation, in feet 164.05 170.61 175.52 Contents, in acre-feet 28,550 33,160 37,040 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN OCT 166.30 A 166.29 165.90 165.98 166.06 166.14 166.18 166.22 166.28 166.36 165.84 165.90 165.92 165.93 165.94 165.93 165.88 165.90 165.99 166.01 166.01 166.01 165.98 165.93 NOV 165.87 165.86 165.88 165.87 165.94 165.94 165.93 165.94 166.00 166.10 166.34 166.00 165.89 165.70 165.95 166.09 166.24 165.81 166.01 166.28 166.32 166.05 166.40 165.79 165.99 DEC 166.12 165.81 166.05 166.22 165.88 165.61 165.69 165.75 165.78 165.84 166.07 165.68 165.99 166.30 165.86 165.97 165.74 165.85 165.93 165.97 166.03 166.04 166.06 166.10 166.12 JAN 165.81 165.92 166.00 166.03 166.06 166.06 166.03 165.99 165.94 165.89 165.86 165.82 165.83 165.78 165.82 165.81 165.77 165.75 165.80 165.95 166.73 166.65 166.65 166.64 166.58 FEB 166.69 166.64 166.69 166.62 166.74 166.70 166.61 166.69 166.56 166.63 166.68 166.75 166.58 166.67 166.73 166.71 166.56 166.60 166.64 166.70 166.78 166.60 166.69 166.72 166.61 MAR 166.61 166.62 166.69 166.72 166.64 166.66 166.67 166.70 166.68 166.63 166.57 166.51 166.44 166.37 166.30 166.23 166.16 166.12 166.04 165.93 165.80 165.68 165.57 165.43 165.29 APR 165.08 165.00 165.69 165.78 165.73 165.65 165.56 165.43 165.28 165.12 164.97 164.80 164.62 164.44 164.24 164.04 163.87 163.71 163.53 163.32 163.13 162.89 162.67 162.43 162.19 MAY 160.87 160.65 160.51 160.29 160.07 159.84 159.62 159.39 159.14 158.93 158.79 158.58 158.36 158.14 157.90 157.69 157.48 157.34 157.11 156.87 156.62 156.36 156.37 158.47 159.43 JUN 159.13 159.07 159.02 158.85 158.67 158.43 158.10 157.85 157.62 157.37 157.13 156.89 156.62 156.32 156.04 155.75 155.46 155.18 155.06 154.81 154.53 154.26 154.01 153.74 153.47 JUL 151.70 151.37 151.02 150.67 150.31 149.96 149.60 149.29 148.98 148.65 148.31 147.96 147.59 147.21 146.85 146.49 146.12 145.84 145.76 145.55 145.41 145.57 145.46 145.20 144.96 AUG 142.88 142.55 142.19 141.86 141.50 141.14 140.78 140.46 140.09 139.77 139.52 139.20 138.88 138.55 138.23 137.83 137.70 137.43 137.09 136.75 136.40 136.15 137.53 137.95 139.09 SEP 137.55 137.23 136.88 136.53 136.12 135.71 135.39 134.95 134.98 134.81 134.44 134.08 133.82 133.56 133.23 132.83 132.43 132.05 131.60 131.15 130.78 130.67 130.44 130.38 130.13 166.10 165.97 165.89 165.95 165.72 165.79 166.30 165.82 166.18 165.71 165.84 ___ 166.20 165.76 165.91 165.68 166.09 165.60 166.75 166.68 166.78 166.73 166.72 166.64 166.67 166.66 166.63 ___ ___ ___ 165.17 165.03 164.96 165.18 165.27 165.16 161.96 161.73 161.50 161.28 161.08 ___ 159.65 159.61 159.47 159.41 159.27 159.16 153.21 152.91 152.61 152.33 152.03 ___ 144.65 144.33 144.00 143.66 143.42 143.19 139.16 138.94 138.62 138.44 138.16 137.87 129.86 129.93 129.70 129.36 128.95 ___ 166.40 165.70 166.30 165.60 166.78 165.75 166.78 166.56 166.72 164.96 165.78 161.08 160.87 156.36 159.13 152.03 151.70 143.19 142.88 136.15 137.55 128.95 A No gage-height record RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR 755 LOCATION.--Lat 18°20'45", long 66°14'17», Hydrologic Unit 21010005, 2.8 mi (4.5 km) west of Road 167, km 15.3, Buena Vista, Bayamon, 5.0 mi (8.0 km) east of Plaza de Corozal, 3.0 mi (4.8 km) northeast of Plaza de Naranjito. DRAINAGE AREA.--173 mi 2 (448 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—July 1989 to current year. GAGE.—Water-stage recorder. Elevation of gage is 164 ft (30 m), from topographic map. REMARKS.--Records poor. Regulation at all stages by Puerto Rico Aqpieduct and Sewer Authority reservoir upstream from gage. Gage-height satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT DEC JAN FEB MAR APR MAY JUN AUG SEP 1 e8.4 e!4 2 e8.0 e6.6 3 e8.2 e8.2 4 elO e8.0 5 e7 . 8 e6 . 6 6 e7.2 e5.8 7 e8.4 e7.2 8 e6.8 e6.2 9 e5.8 eS.O 10 e5 . 3 e7 . 6 11 e5 . 0 e7 . 4 12 e4.9 e50 13 e4.8 e!70 14 eS.l e38 15 e5.5 e49 16 eS.O elO 17 e4 . 8 e7 . 0 18 e4.7 e23 19 e4.5 e60 20 e4.4 e!6 21 e4.7 e40 22 e4.4 e!20 23 e6.3 e!30 24 e4.9 e220 25 e4.2 elOO 26 eS.O e42 27 e76 e49 28 e32 e!5 29 elOO e26 30 e26 e68 31 e40 —— TOTAL 431.1 1315.6 MEAN 13.9 43.9 MAX 100 220 MIN 4.2 5.0 AC-FT 855 2610 CFSM .08 .25 IN. .09 .28 e64 e45 e23 elO e7.4 e44 ell e6.8 e5.8 e5.4 e68 e50 e25 e6.2 e31 e24 e42 eS.O e6.2 e5.2 e5.8 e5.2 e4.9 e!5 e9.0 e25 e80 e!3 e30 e46 elO 731.9 23.6 80 4.9 1450 .14 .16 STATISTICS OF MONTHLY MEAN DATA MEAN 187 74.8 MAX 1107 225 (WY) 1991 1993 MIN .048 .004 (WY) 1992 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 39.8 161 1993 .000 1995 e!2 e4.3 e7.8 e4.0 e2.2 e2.3 el. 8 el. 7 el. 6 el. 5 el. 5 el. 4 el. 4 el. 3 el. 3 el. 3 el. 2 el. 3 el. 6 el. 9 e35 e!20 e66 e60 e30 e20 e9.8 ell e8.2 e6.2 e3.3 422.9 13.6 120 1.2 839 .08 .09 eS.O ell e3.3 e3.5 e4.4 e2.9 e2.4 e2.8 el. 9 e3.5 el. 7 e2.2 e2.5 e3.5 el. 7 el. 7 e4.5 el. 7 el. 5 el. 4 e6.6 eS.O e4.0 e2.9 e2.5 e2.9 el. 4 e2.8 ___ ___ —— 91.2 3.26 11 1.4 181 .02 .02 FOR WATER YEARS 1989 242 1581 1992 .19 1990 37.2 222 1991 .14 1995 FOR 1996 CALENDAR YEAR 258269.20 706 141000 .40 .49 Sep 10 Jul 4 Jun 30 el. 5 el.l e.90 el. 9 e3.1 e4.1 e2.1 e2.1 el. 7 el. 5 el. 3 el. 3 el. 2 el. 2 el.l el.l el.l el. 2 el.l el.l el.O el.O .98 .92 .88 .84 .80 .88 .96 .82 .72 .70 .78 .80 .82 .80 .76 .78 .76 .74 .74 .80 .80 .78 .72 .70 .72 .76 .80 .82 .82 .82 .82 .70 .66 .62 .70 .72 .66 .64 .76 41.54 22.46 1.34 .75 4.1 .82 .76 .62 82 45 .01 .00 .01 .00 e.64 e.62 el.l el.O e.74 e.69 e.64 e.58 e.52 e.50 e.52 e.54 e.56 e.61 e.66 e.92 e.64 e.42 .34 .28 .35 .35 .34 2.6 1.4 .92 .53 .34 .32 .48 .29 20.44 .66 2.6 .28 41 .00 .00 .28 .22 .25 .23 .28 .30 .30 .24 .21 .25 .31 .36 .40 .45 .53 .63 .71 .93 1.5 1.3 .84 .14 .02 .02 .01 .01 .01 .01 .00 .00 —— 10.74 .36 1.5 .00 21 .00 .00 .00 .00 .00 .00 .01 .04 .07 .09 .03 .03 .02 .02 .02 .02 .06 .11 .14 .18 .40 .42 .34 .30 .23 .19 .16 .17 .16 .17 .15 .15 .26 3.94 .13 .42 .00 7.8 .00 .00 .32 .31 .29 .29 .30 .29 .28 .24 .26 .32 .46 .58 .65 .50 .45 .39 .41 .60 .49 .46 .48 .89 1.1 1.7 1.4 .82 .69 .63 .60 .91 1.1 18.21 .59 1.7 .24 36 .00 .00 .88 .82 .73 .73 .73 .73 .99 .97 1.1 1.1 .93 1.0 1.6 1.8 1.6 1.1 1.0 1.1 1.2 1.1 1.3 1.7 1.5 1.4 1.3 1.3 1.3 1.3 1.4 1.5 —— 35.21 1.17 1.8 .73 70 .01 .01 - 1997, BY WATER YEAR (WY) 17.8 34.7 83.2 231 1990 1993 .022 .011 1995 1995 FOR 1997 3145 8 220 123 494 1993 .000 1994 WATER YEAR .24 .62 Nov 24 .00 Jun 29 .00 Jun 28 43.0 220 1993 .002 1994 unknown Nov 24 unknown Nov 24 512300 4.08 55.60 116 3.8 .60 6240 24 1 .050 .68 .2 .23 72.7 384 1993 .037 1994 WATER 170 714 8 141000 197000 42 122900 13 159 1 29.8 129 1996 .020 1989 YEARS 1989 .62 Sep .00 Jul .00 Jul Sep .26 Sep .98 .34 .0 .00 1127 8046 1996 .001 1991 - 1997 1996 1997 10 1996 14 1989 14 1989 10 1996 10 1996 e Estimated 755 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA AT BELOW LA PLATA DAM, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1989 to current year. INSTRUMENTATION.-- Automatic sediment sampler since 1989. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 4,390 mg/L September 10, 1996; Minimum daily mean, <.05 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 1,810,000 tons (1,640,,000 tonnes) September 10, 1996; Minimum daily mean, <0.01 ton (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 181 mg/L January 16, 1997; Minimum daily mean, 1 mg/L July 1, 1997. SEDIMENT LOADS: Maximum daily mean, e!4 tons (e!3 tonnes) January 22, 1997; Minimum daily mean, <0.01 ton (<0.01 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e8.4 e8.0 e8.2 elO e7.8 e7.2 e8.4 e6.8 e5.8 e5.3 e5.0 e4.9 e4.8 e5.1 e5.5 e5.0 e4.8 e4.7 e4.5 e4.4 e4.7 e4.4 e6.3 e4.9 e4.2 e8.0 e76 e32 elOO e26 e40 13 .30 13 14 14 14 13 13 13 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 .29 .30 .37 .30 .26 .29 .24 .20 .18 .16 .16 .16 .16 .18 .16 .16 .15 .15 .14 .15 .14 .20 .16 .14 14 e.28 18 e3.2 18 el. 8 19 e4.7 18 el. 7 17 el. 8 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER e!4 e6.6 e8.2 e8.0 e6.6 e5.8 e7.2 e6.2 e5.0 e7.6 e7.4 e50 e!70 e38 e49 elO eV.O e23 e60 el 6 e40 e!20 e!30 e220 elOO e42 e49 el5 e26 668 ___ 17 14 13 13 13 13 13 13 13 13 13 15 20 21 19 16 14 14 17 17 16 18 20 23 23 20 18 16 16 19 ___ .75 .28 .28 .28 .24 .21 .25 .22 .18 .25 e.26 el. 8 e8.4 62.9 62.4 e.59 e.28 6.81 62.6 e.94 el. 6 65.3 67.0 613 66.9 62.6 62.3 e.79 el.l 63.1 ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 664 645 623 elO 67.4 644 ell 66.8 65.8 65.4 668 650 625 66.2 631 624 642 68.0 66.2 65.2 65.8 65.2 64.9 615 69.0 625 680 613 630 646 elO 19 18 16 15 14 15 17 15 14 13 16 19 16 14 14 15 17 17 14 13 13 12 12 13 15 17 19 17 15 17 17 63.3 62.2 el.l 6.46 e.28 el. 6 e.65 e.30 e.22 6.19 62.5 62.6 el. 2 6.30 el.O el.O el. 8 .50 .25 .19 .19 .18 .16 .47 .38 el.O e3.7 e.88 el.l e2.0 e.62 TOTAL 431.1 18.58 1315.6 67.61 731.9 32.32 e Estimated RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 157 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN DISCHARGE (CPS) e!2 e4.3 e7.8 e4.0 e2.2 e2.3 el. 8 el. 7 el. 6 el. 5 el. 5 el. 4 el. 4 el. 3 el. 3 el. 3 el. 2 el. 3 el. 6 el. 9 e35 e!20 e66 e60 e30 e20 e9.8 ell e8.2 e6.2 e3.3 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 16 .48 14 13 12 11 12 16 21 28 37 50 67 89 119 159 181 103 53 27 14 .19 .25 .14 .07 .07 .08 .10 .12 .15 .20 .25 .34 .42 .56 .64 .34 .18 .12 .07 17 el. 4 45 e!4 68 e!3 63 elO 59 e5.3 55 e3.2 50 el. 5 36 el.l 26 e.60 18 e.32 13 e.13 MEAN DISCHARGE (CPS) eS.O ell e3.3 e3.5 e4.4 e2.9 e2.4 e2.8 el. 9 e3.5 el. 7 e2.2 e2.5 e3.5 el. 7 el. 7 e4.5 el. 7 el. 5 el. 4 e6.6 eS.O e4-0 e2.9 e2.5 e2.9 el. 4 e2.8 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY 12 .15 13 14 13 12 12 11 11 10 10 10 10 11 11 11 11 12 12 12 13 13 13 12 11 11 10 9 9 .36 .15 .12 .14 .10 .08 .08 .05 .09 .05 .06 .07 .10 .06 .05 .13 .06 .05 .05 .20 .18 .13 .09 .07 .08 .04 .06 —— —— MEAN DISCHARGE (CPS) el. 5 el.l e.90 el. 9 e3.1 e4.1 e2.1 e2.1 el. 7 el. 5 el. 3 el. 3 el. 2 el. 2 el.l el.l el.l el. 2 el.l el.l el.O el.O .98 .92 .88 .84 .80 .88 .96 .82 .76 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 8 .05 8 7 7 7 7 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 .03 .02 .03 .05 .07 .06 .05 .04 .04 .03 .03 .03 .03 .03 .03 .03 .03 .03 .03 .03 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 422.9 55.32 91.2 2.85 41.54 0.97 Estimated 158 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN DISCHARGE DAY (CFS) 1 .72 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 .70 .78 .80 .82 .80 .76 .78 .76 .74 .74 .80 .80 .78 .72 .70 .72 .76 .80 .82 .82 .82 .82 .70 .66 .62 .70 .72 .66 .64 31 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 9 .02 9 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .01 .01 .02 .02 .02 .02 .02 .02 .02 .01 .01 .01 .01 .01 .01 —— —— MEAN DISCHARGE (CFS) e.64 e.62 el.l el.O e.74 e.69 e.64 e.58 e.52 e.50 e.52 e.54 e.56 e.61 e.66 e.92 e.64 e.42 .34 .28 .35 .35 .34 2.6 1.4 .92 .53 .34 .32 .48 .29 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 8 .01 8 8 8 8 8 8 8 8 8 8 8 8 8 17 23 23 14 .01 .02 .02 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .03 .05 .05 .02 8 .01 14 .01 27 .03 17 .02 9 .01 13 .10 10 .04 7 .02 5 .01 6 <.01 7 .01 13 .02 23 .02 MEAN DISCHARGE (CFS) .28 .22 .25 .23 .28 .30 .30 .24 .21 .25 .31 .36 .40 .45 .53 .63 .71 .93 1.5 1.3 .84 .14 .02 .02 .01 .01 .01 .01 .00 .00 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 27 29 31 29 15 9 14 20 16 11 7 4 6 8 7 7 6 6 5 5 5 6 8 11 14 19 25 31 30 29 .02 .02 .02 .02 .01 .01 .01 .01 .01 .01 .01 •c.Ol .01 .01 .01 .01 .01 .01 .02 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 TOTAL 22.46 0.52 20.44 0.62 10.74 0.26 e Estimated RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY}, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 759 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR .00 .00 .00 .00 .01 .04 .07 .09 .03 .03 .02 .02 .02 .02 .06 .11 .14 .18 .40 .42 .34 .30 .23 .19 .16 .17 .16 .17 .15 .15 .26 3.94 3145.24 JULY <1 .01 26 24 23 20 17 10 £ £ £ 3 2 g 35 28 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 21 .01 39 .01 81 .04 75 .08 61 .07 72 .07 69 .06 24 .01 8 <.01 3 <.01 1 <.01 5 <.01 19 .01 12 <.01 5 <.01 7 <.01 0.36 180.66 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) AUGUST .32 .31 .29 .29 .30 .29 .28 .24 .26 .32 .46 .58 .65 .50 .45 .39 .41 .60 .49 .46 .48 .89 1.1 1.7 1.4 .82 .69 .63 .60 .91 1.1 18.21 12 15 19 24 29 31 31 24 18 13 11 16 22 16 10 8 6 4 2 3 5 5 5 4 3 2 2 9 34 17 19 —— .01 .01 .01 .02 .02 .02 .02 .02 .01 .01 .01 .03 .04 .02 .01 .01 .01 .01 <.01 <.01 .01 .01 .01 .02 .01 <.01 <.01 .01 .05 .04 .05 0.50 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) .88 .82 .73 .73 .73 .73 .99 .97 1.1 1.1 .93 1.0 1.6 1.8 1.6 1.1 1.0 1.1 1.2 1.1 1.3 1.7 1.5 1.4 1.3 1.3 1.3 1.3 1.4 1.5 SEPTEMBER 20 12 7 3 2 1 4 8 3 1 2 4 3 2 5 9 8 6 8 8 5 4 6 12 14 14 12 11 16 20 35.21 .05 .03 .01 .01 .01 .02 .01 .01 .01 .01 .01 .02 .03 .02 .02 .02 .02 .02 .02 .03 .05 .05 .05 .04 .04 .06 .08 0.75 160 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE JAN 1997 27... JUN 30... JDL 02... 18... AUG 29... TIME 1045 0815 0830 1430 1400 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) e9.8 <0.01 <0.01 0.15 0.60 SEDI- MENT, SUS- FENDED (MQ/L) (80154) 52 77 66 95 48 SEDI- MENT, DIS- CHARGE, SUS- FENDED (T/DAY) (80155) el. 4 <0.01 <0.01 0.04 0.08 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 86 99 98 93 90 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HIGHWAY 2 NEAR TOA ALTA, PR 161 LOCATION.--Lat 18°24'41", long 66°15'39", Hydrologic Unit 21010005, on left bank, at downstream side of bridge on Highway 2, 1.3 mi ( 2.1 km) downstream from Rio Lajas, and 1.6 mi (2.6 km) northwest of Toa Alta, 11.3 mi (18.2 km) downstream from Puerto Rico Aqueduct and Sewer Authority reservoir. DRAINAGE AREA.--208 mi 2 (539 km2 ), excludes 8.2 mi 1 (21.2 km2 ) upstream from Lago Carite, flow from which is diverted to Rio Guamani. Area at site used prior to September 25, 1984, 200 mi 2 (518 km 2 ). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—November 1959 (measurement only), January 1960 to current year. Prior to October 1984, published as Rio de la Plata at Toa Alta, PR; October 1984 to September 1988 published as 50046900. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 9.15 ft (2.789 m), above mean sea level, to October, 1984, at site about 1.0 mi (1.6 km) upstream at mean sea level datum. Prior REMARKS.—Records poor. Regulation at all stages by Puerto Rico Aqueduct and Sewer Authority reservoir upstream from gage. Gage-height and precipitation satellite telemetry at station. Flow affected by bridge construction about 1.0 mi (1.6 km) upstream from station. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate discharges and elevations of major floods, as pointed out by local residents are as follows: Sept. 13, 1928, 120,000 ftVs (3,400 mVs), gage height, 37.4 ft (11.40 m); June 16, 1943, 82,000 ftVs (2,322 mVs), gage height, 34.4 ft (10.48 m), at site 1.0 mi upstream and different datum. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC JAN MAR JUN JUL AUG SEP 1 e65 59 2 e60 50 3 e65 63 4 e80 63 5 e55 50 6 e56 45 7 e65 57 8 e50 47 9 e45 38 10 e40 59 11 e39 56 12 e38 605 13 e37 1330 14 e40 289 15 e43 379 16 e40 58 17 e36 52 18 36 87 19 34 464 20 34 120 21 36 230 22 33 e963 23 49 elOOO 24 34 1710 25 32 684 26 60 311 27 603 e382 28 243 112 29 801 142 30 196 532 31 327 TOTAL 3372 10037 MEAN 109 335 MAX 801 1710 MIN 32 38 AC -FT 6690 19910 CFSM .54 1.67 IN. .63 1.87 STATISTICS OF MONTHLY MEAN MEAN 457 422 MAX 4813 2015 (WY) 1971 1985 MIN 18.8 18.4 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 496 305 153 71 64 350 64 55 53 50 615 403 221 55 263 190 336 56 47 45 47 46 43 137 e76 128 779 116 221 438 199 6122 197 779 43 12140 .99 1.14 232 82 151 108 44 44 35 33 31 30 30 28 27 26 26 24 23 23 30 32 1420 2680 1240 1130 682 386 178 200 159 146 94 9374 302 2680 23 18590 1.51 1.75 DATA FOR WATER 316 1352 1971 14.8 1995 FOR 187 929 1992 16.9 1984 149 366 109 112 149 96 79 95 62 121 57 e72 e74 126 56 55 e!71 e55 55 51 193 171 149 97 82 97 50 106 —— 3055 109 366 50 6060 .55 .57 YEARS 1960 126 409 1989 16.0 1983 48 48 53 58 103 149 75 75 62 50 43 45 43 41 40 40 39 41 39 38 36 36 34 32 30 29 27 28 33 29 25 1469 47.4 149 25 2910 .24 .27 - 1997 98.4 468 1969 8.31 1986 1996 CALENDAR YEAR 139193 380 68100 13 18 276100 1. 25. 445 50 22 Sep 10 May 15 May 12 90 92 25 25 27 27 28 28 26 27 26 26 25 28 27 27 25 24 25 26 27 28 29 29 29 24 23 21 24 25 23 22 —— 776 25.9 29 21 1540 .13 .14 22 21 39 37 24 24 22 20 20 21 21 21 21 21 22 24 24 21 22 22 29 23 23 e!46 e!09 75 57 35 28 28 29 1051 33.9 146 20 2080 .17 .20 34 35 31 31 32 31 25 26 26 28 25 25 24 22 22 23 22 e22 e80 49 28 26 54 47 35 40 55 47 41 39 —— 1025 34.2 80 22 2030 .17 .19 34 32 27 25 27 34 32 27 27 27 27 33 35 24 22 40 50 64 41 31 36 20 18 17 26 22 18 18 17 19 38 908 29.3 64 17 1800 .15 .17 33 20 19 18 17 17 15 15 27 45 53 74 62 62 51 74 143 121 48 33 74 134 89 199 212 53 35 28 24 23 26 1844 59.5 212 15 3660 .30 .34 25 18 16 13 12 11 12 12 11 12 12 12 61 176 68 30 22 20 20 20 50 60 44 86 65 37 31 27 36 60 —— 1079 36.0 176 11 2140 .18 .20 , BY WATER YEAR (WY) 181 723 1987 5.07 1984 FOR 1997 40112 110 2680 11 12 4350 10 11 79560 7 216 40 21 339 1939 1985 7.63 1984 WATER YEAR Jan 22 Sep 6 Sep 5 Jan 22 .80 Jan 22 Sep 6 .55 .47 160 847 1970 11.4 1977 146 690 1961 13.2 1994 242 1677 1979 16.5 1976 WATER YEARS 1960 - Not 254 824 31.5 68100 2.7 2.9 determined 27.33 184100 1.27 17.28 476 83 17 Sep 10 Apr 17 Apr 15 Sep 10 Sep 10 399 3173 1996 19.2 1991 1997 1971 1994 1996 1984 1984 1996 1996 e Estimated 162 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HWY 2 NR TOA ALTA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°24'41", long 66°15'39", at Highway 2, 1.3 mi (2.1 km) downstream from Rio Lajas, and 1.6 mi (2.6 km) northwest of Toa Alta, 11.3 mi (18.2 km) downstream from Puerto Rico A<xueduct and Sewer Authority reservoir. DRAINAGE AREA.--208 mi 2 (539 km2 ), exclude 8.2 mi 2 (21.2 km2 ) upstream from Lago Carite, flow from which is diverted to Rio Guamani. PERIOD OF RECORD.—Water years 1958 to current year WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 15... FEB 1997 20... MAY 14... SEP 08... DATE OCT 1996 15... FEB 1997 20... MAY 14... SEP 08... DATE OCT 1996 15... FEB 1997 20... MAY 14... SEP 08... OCT 1996 15... FEB 1997 20... MAY 14... SEP 08... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEC C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1130 43 410 6.7 29.5 0.40 7.7 99 <10 K720 K64 1305 51 500 7.0 25.0 1.8 7.4 86 <10 K1100 K140 1510 20 514 8.2 30.5 2.3 12.8 169 12 K740 K82 1130 13 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 160 — 200 170 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.12 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.50 0.48 0.45 0.36 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 47 — 57 42 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 16 — 18 19 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.3 0.84 0.85 566 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 9.5 — 14 9.8 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 231 — 288 218 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 4.7 5.8 3.7 3.8 7.6 30.0 0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 18 — 26 21 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) ,26.6 — 15.9 7.65 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 0.040 0.040 <0.020 SODIUM AD- SORP- TION RATIO (00931) 0.6 — 0.8 0.6 RESIDUE TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) (00530) 5 1 3 2 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — 2 __ .50 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.5 — 2.8 2.1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.510 0.770 0.360 0.490 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — 6.4 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 160 190 190 200 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.050 0.060 0.030 0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 — 50 — 85 SULFIDE TOTAL (MG/L AS S) (00745) 0.8 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.560 0.830 0.390 0.500 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — <10 K150 K100 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 16 — 18 12 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.130 0.010 0.050 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 25 — 38 19 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.48 0.35 0.44 0.31 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — non-ideal count DATE OCT 1996 15... FEB 1997 20... MAY 14... SEP 08... RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HWY 2 MR TOA ALT A, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MANGA- ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL PHENOLS (UG/L (MG/L TOTAL AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 163 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) NESE, TOTAL RECOV- ERABLE (UG/L AS MN) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) SELE- NIUM, TOTAL (UG/L AS SE) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) 210 140 <1 <1 120 160 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 0.05 164 THIS PAGE WAS LEFT BLANK INTENTIONALLY 165 ATLANTIC OCEAN tRUJILLO ALTO ^ •- ^y EXPLANATION A 047535 SURFACE-WATER STATION AND NUMBER T 0478 QUALJTY-OF-WATER STATION AND NUMBER DAILY SEDIMENT STATION AND NUMBER WELL AND WELL NUMBER 047560 219 047550 LAKE-ELEVATION STATION AND NUMBER ;-»c*»u*» J> fa10123456 KILOMETERS 01234 MILES Figure 18.-Rio Hondo to Rio Puerto Nuevo basins. 166 RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CATANO, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°26'13", long 66 009'36", at Rio Hondo Channel, 800 ft (245 m) below junction with Rio Hondo, 0.9 mi (1.5 km) downstream from bridge on de Diego Expressway and 1.1 mi (1.8 km) above mouth. DRAINAGE AREA.—Indeterminate. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... TIME 0800 0930 1045 1330 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) TEMPER- ATURE WATER (DEG C) (00010) TUR- BID- ITY (NTU) (00076) OXYGEN, DIS- SOLVED (MG/L) (00300) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 380 17500 3690 39000 7.2 6.9 7.7 7.8 25.0 25.0 30.5 32.0 73 1.6 43 17 4.2 4.2 2.9 7.6 50 53 38 96 27 89 36 92 K5600 4100 K71000 2100 450 500 4200 K70 DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS SO4) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 310 49 45 360 360 39 63 553 4500 320 902 7500 13 49 16 26 290 130 150 66 170 <0.5 95 620 <0.5 130 1000 1900 14000 DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.16 0.52 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 9.6 — 5.1 1.8 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 1270 — 1860 24900 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 72 17 39 38 NITRO GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.530 0.280 0.247 — NITRO- NITRO- NITRO- NITRO- GEN, GEN, GEN, GEN, NITRITE NO2+NO3 AMMONIA ORGANIC TOTAL TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L (MG/L AS N) AS N) AS N) AS N) (00615) (00630) (00610) (00605) 0.080 0.600 0.460 0.70 0.080 0.370 0.860 0.59 0.043 0.290 0.400 0.90 <0.010 0.020 0.030 1.2 NITRO- GEN, AM- MONIA + ORGANIC TOTAL DATE (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... 1.2 1.5 1.3 1.2 0.150 0.200 0.120 0.070 <100 <100 180 290 <1 <1 K - non-ideal count Discharge measurement values not available due to ponded conditions. DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 400 910 RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CATANO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 167 MANGA- LEAD, NESE, MERCURY SILVER, TOTAL TOTAL TOTAL SELE- TOTAL RECOV- RECOV- RECOV- NIUM, RECOV- ERABLE ERABLE ERABLE TOTAL ERABLE (UG/L (UG/L (UG/L (UG/L (UG/L ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL PHENOLS (UG/L (MO/L TOTAL AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 140 120 <0.10 <0.10 <1 <1 <1 <1 30 <0.010 <0.010 METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 0.08 0.12 168 RIO DE BAYAMON BASIN 50047535 RIO DE BAYAMON AT ARENAS, PR LOCATION.--Lat 18°10'11", long 66°07'18", Bydrologic Unit 21010005, at left bank, 2.61 ml (4.20 ka) southeast of plaza de Cldra, 0.56 ml (0.90 km) southwest from Escuela Segunda Unidad de Bayam6n, and 2.70 ml (4.34 km) northeast from Central Cayey. DRAINAGE AREA.--0.45 ml 2 (1.16 km2 ). PERIOD OF RECORD.--July 1992 to September 1993, October 1995 to current year. GAGE.—Water-stage recorder. Elevation of gage Is 1,378 ft (420 m), from topographic map. REMARKS.--Records fair. DISCHARGE, CUBIC FEET PER SECOND, MATER YEAR OCTOBER 1996 TO S DAY OCT NOV 1 .28 .28 2 .30 .31 3 .29 .24 4 .25 .25 5 .26 .24 6 .24 .23 7 .26 .26 8 .27 .24 9 .30 .26 10 .33 .25 11 .29 .66 12 .26 1.5 13 .25 .81 14 .24 .41 15 .25 .28 16 .24 .21 17 .24 .19 18 .24 .23 19 .24 .21 20 .24 .35 21 .24 .30 22 .25 .30 23 .24 .35 24 .24 .46 25 .24 .50 26 .36 .26 27 .40 .32 28 .38 .37 29 .79 .29 30 .46 1.1 31 .31 TOTAL 9.18 11.66 MEAN .30 .39 MAX .79 1.5 MIN .24 .19 AC-FT 18 23 CFSM .66 .86 IN. .76 .96 STATISTICS OF MONTHLY MEAN MEAN .31 .78 MAX .34 1.30 (WY) 1996 1993 MIN .30 .39 (WY) 1997 1997 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC .62 .67 .37 .32 .27 .23 .32 .24 .20 .20 .70 .37 .24 .21 .20 .21 .19 .18 .19 .21 .19 .18 .17 .17 .21 .18 .18 .24 .29 .84 .69 9.48 .31 .84 .17 19 .68 .78 JAN .36 .27 .23 .22 .19 .16 .15 .14 .14 .15 .29 .22 .18 .15 .18 .19 .16 .16 .19 .27 1.3 3.2 1.8 2.1 1.4 .73 .48 .51 .60 .41 .35 16.88 .54 3.2 .14 33 1.21 1.40 DATA FOR WATER .36 .63 1993 .16 1996 FOR .60 .63 1996 .54 1997 DAILY FEB 1.5 .73 .41 .25 .25 .28 .28 .25 .52 .32 .29 .31 .55 .48 .38 .25 .20 .20 .39 .36 1.3 .75 1.5 .50 .37 .34 .27 .25 ___ ___ —— 13.48 .48 1.5 .20 27 1.07 1.11 YEARS 1992 .29 .48 1997 .16 1993 EjrTBHhBR 1997 MEAN VALUES MAR .25 .23 .35 .31 .28 .21 .16 .29 .27 .21 .15 .11 .12 .09 .12 .13 .11 .12 .12 .12 .12 .12 .11 .12 .12 .12 .12 .15 .25 .22 .15 5.35 .17 .35 .09 11 .38 .44 - 1997 .14 .17 1997 .097 1993 1996 CALENDAR YEAR 421. 1. 141 . . 835 2. 34. 1. . . 09 15 Sep 10 03 May 2 04 Apr 28 56 81 5 24 07 APR .15 .26 .29 .15 .10 .09 .08 .08 .08 .07 .11 .09 .10 .09 .08 .07 .07 .07 .07 .07 .07 .08 .07 .07 .07 .07 .06 .06 .07 .06 —— 2.85 .095 .29 .06 5.7 .21 .24 MAY .07 .07 .07 .06 .06 .06 .06 .06 .07 .09 .06 .08 .07 .06 .07 .10 .32 .09 .07 .06 .08 .06 .06 .14 .08 .07 .08 .07 .22 .32 .33 3.16 .10 .33 .06 6.3 .23 .26 JUN .22 .31 .61 .22 .14 .11 .10 .09 .09 .09 .10 .09 .09 .21 .09 .07 .06 .05 .07 .09 .06 .05 .28 .21 .07 .09 .06 .04 .04 .03 —— 3.83 .13 .61 .03 7.6 .28 .32 JUL .03 .03 .02 .02 .04 .38 .08 .04 .06 .07 .05 .03 .03 .03 .02 .39 .16 .16 .14 .29 1.2 .60 .63 .50 .23 .26 .11 .72 .27 .12 .09 6.80 .22 1.2 .02 13 .49 .56 AUG .09 .04 .07 .07 .04 .04 .03 .04 .02 .05 .06 .03 .03 .03 .04 .07 .37 .17 .51 .10 .06 4.8 .66 14 1.8 .33 .15 .11 .09 .09 .24 24.23 .78 14 .02 48 1.74 2.00 SEP .22 .31 .18 .16 .15 .15 .24 1.0 .52 .12 .08 .32 .14 .17 .11 .10 .09 .11 .09 .07 .17 .16 .16 .22 .11 .35 .16 .11 .10 .09 —— 5.96 .20 1.0 .07 12 .44 .49 , BY WATER YEAR (WY) .22 .45 1993 .095 1997 FOR 1997 112 14 228 5 224 9 .75 2.02 1993 .10 1997 WATER YEAR .86 .31 Aug 24 . 02 Jul 3 .03 Jun 28 Aug 24 .21 Aug 24 .02 Jul 15 .69 .33 .51 .19 .06 .97 1.79 1996 .13 1997 1.31 2.12 1993 .22 1997 WATER 1 141 885 7 561 1 23 1 .96 1.87 1996 .46 1992 YEARS 1992 - .77 .16 .31 Sep 10 . 02 Jul 3 .03 Jun 28 Sep 10 .34 Sep 10 .02 Jul 15 .72 .36 .1 .18 .07 2.20 6.38 1996 .20 1997 1997 1996 1997 1996 1997 1997 1996 1996 1997 RIO DE BAYAMON BASIN 50047540 RIO SABANA AT VISTA MONTE, PR 169 LOCATION.—Lat 18°10'28", long 66°08'38", Hydrologic Unit 21010005, at left bank, 1.2 mi (1.9 km) southeast of Plaza de Cidra, 1.2 ml (1.9 km) southwest from Escuela Segunda Unidad de Bayamon, and 0.4 ml (0.6 km) upstream from Lago de Cidra. DRAINAGE AREA.--0.80 ml 2 (2.07 km2 ). PERIOD OF RECORD.—August 1992 to September 1993, October 1995 to current year. GAGE.—Hater-stage recorder and crest-stage gage. Elevation of gage is 1,345 ft (410 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV 1 1.0 .66 2 .93 .72 3 .91 .56 4 .81 .58 5 .80 .56 6 .82 .54 7 .76 .60 8 .69 .56 9 .81 .60 10 .75 .58 11 .67 el. 5 12 .68 e3.5 13 .63 e2.7 14 .60 el. 5 15 .59 el.O 16 .60 e.72 17 .60 e.64 18 .62 e.76 19 .63 e.78 20 .64 1.0 21 .61 1.3 22 .60 .99 23 .60 1.0 24 .57 1.1 25 .55 1.1 26 .73 .90 27 .85 1.2 28 .75 1.4 29 el. 8 .96 30 el.l 1.6 31 e.74 —— TOTAL 23.44 31.48 MEAN .76 1.05 MAX 1.8 3.5 MIN .55 .45 AC-FT 46 62 CFSM .95 1.31 IN. 1.09 1.46 DEC 1.1 1.1 .93 .95 .87 .84 .83 .79 .78 .75 1.1 .84 .79 .79 .80 .76 .75 .72 .70 .71 .74 .67 .68 .72 .72 .72 .73 .85 .78 1.1 1.9 26.51 .86 1.9 .67 53 1.07 1.23 STATISTICS OF MONTHLY MEAN DATA MEAN .79 1.22 MAX .86 1.56 (WY) 1993 1993 MIN .76 1.05 (WY) 1997 1997 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS .82 1.11 1993 .48 1996 FOR JAN .86 .79 .74 .71 .68 .66 .63 .64 .63 .66 .66 .62 .63 .64 .64 .64 .62 .63 .68 .70 1.4 4.4 1.8 1.9 1.8 1.3 1.1 1.1 1.1 1.1 .99 31.45 1.01 4.4 .62 62 1.27 1.46 FEB 2.0 1.4 1.2 1.0 1.1 1.1 .97 .94 1.1 .96 .94 .97 1.1 1.1 1.0 .94 .93 .91 1.1 1.0 1.6 1.1 1.5 .82 .73 .72 .66 .64 ___ —— 29.53 1.05 2.0 .64 59 1.32 1.37 FOR WATER YEARS 1992 .86 1.01 1997 .72 1993 .68 1.05 1997 .33 1993 MAR .62 .64 .72 .66 .70 .64 .61 .76 .60 .58 .56 .56 .58 .58 .63 .57 .56 .56 .56 .56 .55 .56 .56 .55 .56 .55 .56 3.1 .76 .53 .51 21.04 .68 3.1 .51 42 .85 .98 - 1997 .41 .68 1997 .15 1993 1996 CALENDAR YEAR 834.37 2.28 401 .23 .23 1650 2.85 38.80 1.6 .68 .34 Sep 10 Apr 11 Apr 17 APR .47 .60 .63 .49 .47 .46 .44 .44 .44 .44 .47 .44 .45 .43 .43 .47 .45 .44 .43 .44 .45 .46 .45 .44 .43 .44 .49 .48 .48 .43 —— 13.88 .46 .63 .43 28 .58 .65 MAY .42 .42 .42 .42 .41 .41 .42 .47 .46 .46 .44 .47 .45 .43 .43 .43 .77 .43 .38 .37 .35 .34 .39 .38 .34 .33 .40 .34 .38 .45 .42 13.03 .42 .77 .33 26 .53 .61 JUN .32 .41 .43 .28 .27 .25 .24 .23 .21 .21 .23 .21 .22 .24 .20 .20 .19 .20 .24 .19 .19 .19 .67 .24 .21 .22 .20 .19 .19 .19 —— 7.46 .25 .67 .19 15 .31 .35 JUL .19 .19 .19 .21 .21 .42 .25 .24 .25 .24 .28 .24 .23 .23 .24 1.0 .27 .20 .24 .28 .55 .29 .44 .26 .30 .25 .21 .35 .22 .20 .19 8.86 .29 1.0 .19 18 .36 .41 AUG .19 .18 .24 .20 .18 .18 .18 .18 .18 .25 .20 .21 .19 .18 .19 .20 .36 .23 .29 .20 .19 1.9 .31 6.6 .53 .26 .21 .19 .18 .19 .20 14.97 .48 6.6 .18 30 .60 .70 SEP .20 .22 .19 .19 .19 .19 .20 .83 .26 .26 .30 .32 .21 .26 .21 .21 .19 .19 .18 .18 .26 .27 .33 .24 .18 .21 .19 .36 .19 .19 7.40 .25 .83 .18 15 .31 .34 , BY WATER YEAR (WY) .69 1.23 1993 .37 1996 FOR 1997 229 6 46 2 454 10 1 1.05 2.26 1993 .42 1997 WATER YEAR .05 .63 .6 Aug 24 . 18 Aug 2 .19 Jun 27 Aug 24 .41 Aug 24 .16 Aug 7 .78 .65 .1 .55 .19 .78 1.21 1996 .25 1997 1.82 3.02 1993 .29 1997 WATER 1. 2. . 401 . . 2380 12. . 979 1. 22. 1. . . 1.19 2.15 1996 .48 1997 YEARS 1992 - 35 25 63 Sep 10 11 Mar 25 12 Jun 6 Sep 10 02 Sep 10 11 Mar 23 69 96 3 49 19 4.79 16.7 1996 .25 1997 1997 1996 1997 1996 1993 1993 1996 1996 1993 e Estimated 170 RIO DE BAYAMON BASIN 50047550 LAGO CIDRA AT DAMSITE NEAR CIDRA, PR LOCATION.--Lat 18°11'57", long 66°08'29", Rydrologic Unit 21010005, at Lago de Cidra Dan on Rio de Bayamon, 1.9 mi (3.0 km) northeast of Plaza de Cidra and 1.8 mi (2.9 km) northwest of Escuela Segunda Unidad de Bayamon. DRAINAGE AREA.--8.26 mi 2 (21.39 km2 ). ELEVATION RECORDS PERIOD OF RECORD.—January 1988 to current year. GAGE.—Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago de Cidra was completed in 1946. The maximum storage is 5,300 ac-ft (6.53 bra5 ) and provides supple- mental water to metropolitan San Juan. The dam is a concrete gravity and earthfill structure approximately 541 ft (165 m) long between abutments with a maximum structural height of about 78.7 ft (24.0 m). The spillway portion of the dam, length 131 ft (40 m) and crest elevation 1,322 ft (403 m), is an ungated ogee crest located 131 ft (40 m) from the right abutment. This dam is owned by Puerto Rico Aqueduct and Sewer Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 1,328.09 ft (404.80 m), Sep. 10, 1996; minimum elevation 1,295.86 ft (394.98 m), April 22,1995. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximum elevation, 1,322.06 ft (402.96 m), Oet.l; minimum elevation, 1,308.84 ft (398.93 m), Jan. 20,21. DAY MAX MXN Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 1,295 1,305 1,309 1,312 Contents, in acre-feet 860 1,970 2,610 3,100 Elevation, in feet 1,319 1,322 1,328 Contents, in acre-feet 4,400 5,200 6,920 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG 1321.90 1321.80 1321.80 1321.70 1321.57 1321.40 1321.30 1321.20 1321.09 1321.01 1320.90 1320.77 1320.65 1320.52 1320.38 1320.22 1320.06 1319.80 1319.69 1319.48 1319.30 1319.14 1318.96 1318.74 1318.51 1318.09 1317.91 1317.74 1317.54 1317.36 1317.17 1317.01 1316.83 1316.64 1316.44 1316.33 1316.34 1316.31 1316.18 1316.01 1315.83 1315.65 1315.47 1315.26 1315.09 1314.97 1314.81 1314.63 1314.49 1314.34 1313.63 1313.48 1313.29 1313.14 1312.95 1312.74 1312.55 1312.34 1312.11 1311.89 1311.90 1311.88 1311.74 1311.52 1311.34 1311.17 1310.96 1310.76 1310.59 1310.54 1310.48 1310.42 1310.33 1310.16 1309.98 1309.85 1309.84 1309.75 1309.68 1309.60 1309.48 1309.36 1309.26 1309.23 1309.19 1309.18 1309.17 1309.16 1309.07 1309.05 1308.99 1308.94 1308.90 1308.86 1308.84 1308.97 1309.16 1309.29 1309.39 1309.50 1309.93 1309.98 1310.03 1310.07 1310.11 1310.15 1310.18 1310.21 1310.25 1310.27 1310.31 1310.34 1310.38 1310.35 1310.34 1310.32 1310.29 1310.26 1310.23 1310.20 1310.19 1310.17 1310.17 1310.15 1310.13 1310.04 1310.01 1309.99 1309.97 1309.94 1309.90 1309.87 1309.84 1309.81 1309.77 1309.73 1309.69 1309.68 1309.68 1309.69 1309.67 1309.64 1309.63 1309.62 1309.50 1309.47 1309.47 1309.47 1309.47 1309.49 1309.68 1309.72 1309.75 1309.78 1309.81 1309.84 1309.87 1309.89 1309.91 1309.92 1309.93 1309.94 1309.95 1309.96 1309.98 1309.98 1310.00 1310.01 1310.02 1310.02 1310.02 1310.02 1310.02 1310.00 1310.00 1309.94 1309.93 1309.92 1309.85 1309.76 1309.70 1309.65 1309.60 1309.55 1309.52 1309.48 1309.45 1309.46 1309.49 1309.52 1309.56 1309.60 1309.63 1309.66 1309.69 1309.72 1309.76 1309.79 1309.82 1309.85 1309.98 1309.99 1309.98 1309.99 1309.99 1309.99 1310.09 1310.09 1310.09 1310.10 1310.10 1310.11 1310.11 1310.12 1310.12 1310.12 1310.12 1310.12 1309.90 1309.90 1309.90 1309.89 1309.87 1309.87 1309.80 1309.90 1309.89 1309.90 1309.89 1309.82 1309.77 1309.72 1309.72 1309.73 1309.74 1309.75 1309.76 1309.78 1309.79 1309.81 1309.84 1309.87 1309.91 1309.93 1309.98 1310.03 1310.08 1310.13 1310.18 1310.23 1310.55 1310.59 1310.63 1310.67 1310.70 1310.74 1310.78 1310.80 1310.83 1310.86 1310.87 1310.87 1310.86 1310.86 1310.84 1310.84 1310.85 1310.85 1310.85 1310.85 1310.85 1310.88 1310.90 1310.97 1312.79 1313.08 1313.12 1313.16 1313.19 1313.22 1313.24 1313.27 1313.29 1313.32 1313.34 1313.34 1313.31 1313.29 1313.26 1313.25 1313.22 1313.20 1313.17 1313.10 1313.11 1313.08 1313.06 1313.03 1313.01 1312.98 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 1318.36 1314.17 1309.81 1309.58 1310.11 1309.51 1309.99 1309.88 1309.80 1310.28 1312.84 1312.96 27 1318.21 28 1318.13 29 1318.20 30 1318.29 31 1318.26 1314.05 1314.01 1313.80 1313.70 1309.72 1309.69 1309.66 1309.68 1309.77 1309.65 1309.71 1309.77 1309.83 1309.88 1310.09 1310.07 ._. —— 1309.52 1309.55 1309.59 1309.62 1309.65 1309.98 1309.97 1309.96 1309.95 —— 1309.90 1309.93 1309.95 1309.96 1309.97 1309.89 1309.89 1309.89 1309.90 —— 1310.33 1310.38 1310.42 1310.47 1310.50 1312.88 1312.92 1312.96 1313.00 1313.04 1312.93 1312.91 1312.89 1312.85 1321.90 1318.13 1318.09 1313.70 1313.63 1309.66 1309.88 1308.84 1310.38 1309.93 1310.04 1310.02 1309.97 1310.12 1310.50 1313.04 1313.34 1309.47 1309.68 1309.45 1309.80 1309.72 1310.55 1312.85 WTR YR 1997 MAX 1321.90 MIN 1308.84 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR 171 LOCATION.--Lat 18°12'04", long 66°08'26", Hydrologic Unit 21010005, 0.2 ml (0.3 tan) downstream of Lago Cidra Dam on right bank, 2.1 mi (3.4 tan) northwest of Plaza de Cidra. DRAINAGE AREA.—8.31 mi 2 (21.5 tan2 ). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—November 1990 to current year. GAGE.—Hater-stage recorder. Elevation of gage is 1,279 ft (390 m), from topographic map. REMARKS.—Records poor. Regulation at all stages by Puerto Rico Acxueduct and Sewer Authority reservoir upstream from gage. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR JUN JUL AUG SEP 1 18 26 2 18 26 3 18 26 4 19 26 5 22 26 6 21 26 7 21 25 8 21 26 9 21 26 10 21 25 11 21 25 12 21 25 13 21 22 14 20 19 15 22 22 16 24 24 17 23 23 18 26 27 19 29 30 20 30 29 21 26 29 22 22 29 23 25 28 24 29 28 25 29 24 26 29 19 27 29 28 28 24 34 29 17 33 30 16 33 31 20 TOTAL 703 789 MEAN 22.7 26.3 MAX 30 34 MIN 16 19 AC-FT 1390 1560 CFSM 2.73 3.16 IN. 3.14 3.53 STATISTICS OF MONTHLY MEAN MEAN 14.6 22.8 MAX 22.7 41.2 (WY) 1997 1992 MIN 3.74 8.85 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 33 30 29 29 28 28 27 28 28 29 19 12 18 21 20 20 21 20 20 19 19 19 20 22 22 21 21 21 21 18 16 699 22.5 33 12 1390 2.71 3.13 17 19 19 19 e!6 el 5 e!4 e!3 e!4 e!4 e!3 e!3 e!4 e!2 e!3 e!2 ell e!2 e!2 ell e!2 e!2 6.4 5.8 5.4 4.9 6.9 9.1 7.2 10 13 375.7 12.1 19 4.9 745 1.46 1.68 DATA FOR HATER 15.3 30.4 1992 4.36 1994 FOR 18.4 59.6 1992 5.45 1995 13 12 12 11 15 20 16 10 12 13 13 13 18 24 27 27 26 21 16 13 13 14 14 21 23 20 17 15 ___ —— 469 16.8 27 10 930 2.01 2.10 YEARS 1991 17.6 36.5 1991 7.24 1994 15 17 17 16 15 15 16 16 16 16 16 16 18 19 20 18 19 16 23 16 11 10 10 8.6 7.8 8.6 9.3 9.2 9.4 8.7 9.0 441.6 14.2 23 7.8 876 1.71 1.97 - 1997 16.2 23.7 1992 11.4 1994 1996 CALENDAR YEAR 14121. 38. 5420 3. 4. 28010 4. 63. 32 19 11 7 6 Sep 10 4 Jul 24 1 Jun 8 64 14 8.3 7.9 7.9 7.8 7.6 7.6 5.5 4.3 4.8 5.0 5.1 5.2 5.2 5.1 4.8 4.4 4.3 6.0 7.6 7.4 7.3 5.7 5.3 5.4 5.3 5.3 5.1 4.0 3.2 3.2 —— 171.6 5.72 8.3 3.2 340 .69 .77 4.7 7.1 7.2 7.2 6.3 5.5 5.3 5.2 5.3 5.1 5.2 3.7 2.7 2.7 2.7 2.7 4.8 6.0 4.9 3.0 2.9 2.9 4.5 5.6 5.7 5.8 5.7 4.1 3.1 3.3 3.3 144.2 4.65 7.2 2.7 286 .56 .64 3.3 8.5 9.6 6.6 6.5 6.5 6.5 6.8 4.9 3.1 3.1 3.0 4.5 5.3 5.7 4.8 3.4 3.3 3.3 5.2 6.6 6.7 4.3 3.3 3.4 3.6 3.7 3.7 3.8 3.8 —— 146.8 4.89 9.6 3.0 291 .59 .66 3.8 4.1 6.7 6.7 7.2 7.7 6.5 .0 .1 .3 .1 .2 .1 .2 5.9 8.8 6.8 6.8 7.0 7.3 7.3 7.3 7.6 6.7 7.4 6.9 7.2 7.5 7.0 7.0 7.1 193.3 6.24 8.8 3.8 383 .75 .86 7.1 7.3 7.3 7.8 7.3 7.2 7.6 7.5 7.7 8.1 7.2 7.1 7.1 8.7 6.7 7.2 7.0 7.1 8.0 7.2 7.1 7.8 7.1 8.1 7.5 8.5 8.4 7.1 8.7 8.4 8.8 235.7 7.60 8.8 6.7 468 .91 1.05 8.7 10 14 14 13 11 8.8 10 11 11 8.6 7.0 5.8 5.8 5.9 7.2 8.0 8.0 8.1 8.2 8.5 8.7 8.5 8.1 8.0 8.1 8.5 8.2 8.0 8.2 —— 266.9 8.90 14 5.8 529 1.07 1.19 , BY HATER YEAR (WY) 13.1 24.5 1996 5.72 1997 FOR 1997 4635 12 34 2 3 72 9 9200 1 20 26 8 4 9.49 17.0 1996 4.13 1993 HATER YEAR .8 .7 Nov 28 .7 May 13 .5 May 11 Aug 24 .74 Aug 24 .53 .73 .8 .2 9.97 17.8 1992 3.47 1994 14.6 39.6 1993 1.56 1994 HATER 17 36 5 5420 15000 27 12340 2 27 27 11 2 13.5 29.2 1996 1.18 1995 YEARS 1991 .0 .1 .93 Sep . 60 Aug .80 May Sep .34 Sep .05 .82 .5 41.9 233 1996 1.64 1994 - 1997 1996 1994 10 1996 6 1992 1 1995 10 1996 10 1996 e Estimated 172 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1991 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: November 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 3,670 mg/L Jan. 05, 1992; Minimum daily mean, 3 mg/L November 27, 1993 and June 27-28, 1997. SEDIMENT LOADS: Maximum daily mean, 27,700 tons (25,100 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.02 tonne) November 21, 1993. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 256 mg/L August 25, 1997; Minimum daily mean, 3 mg/L June 27-28, 1997. SEDIMENT LOADS: Maximum daily mean, 13 tons (12 tonnes) several days; Minimum daily mean, 0.03 ton (0.03 tonne) June 28, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 (AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 18 18 18 19 22 21 21 21 21 21 21 21 21 20 22 24 23 26 29 30 26 22 25 29 29 29 29 24 17 16 20 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 18 18 18 19 22 21 21 21 21 21 21 21 21 20 22 24 23 26 29 30 26 22 25 29 29 29 29 24 17 16 20 206 219 233 244 223 197 177 178 184 169 142 161 180 182 180 179 174 168 163 158 153 148 143 139 134 130 126 122 120 128 140 9.7 11 11 13 13 11 10 10 11 9.6 7.9 9.2 10 10 11 11 11 12 13 13 11 8.8 9.7 11 10 10 9.7 7.9 5.4 5.5 7.7 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 26 26 26 26 26 26 25 26 26 25 25 25 22 19 22 24 23 27 30 29 29 29 28 28 24 19 28 34 33 33 149 134 116 101 101 105 109 103 94 86 79 72 66 60 55 50 45 41 38 35 26 22 21 23 23 23 26 34 30 31 11 9.3 8.2 7.1 7.1 7.4 7.5 7.2 6.6 5.9 5.3 4.8 3.8 3.1 3.2 3.2 2.8 3.1 3.1 2.8 2.1 1.8 1.6 1.8 1.5 1.2 2.0 3.1 2.7 2.8 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) DECEMBER 33 30 29 29 28 28 27 28 28 29 19 12 18 21 20 20 21 20 20 19 19 19 20 22 22 21 21 21 21 18 16 32 31 30 30 27 24 24 24 26 28 34 41 44 25 11 6 6 7 8 13 21 35 36 31 28 24 23 21 20 18 17 2.9 2.6 2.3 2.4 2.1 1.8 1.8 1.9 2.0 2.2 1.7 1.3 2.1 1.5 .60 .36 .35 .38 .47 .67 1.1 1.8 1.9 1.8 1.7 1.4 1.3 1.2 1.2 .91 .73 TOTAL 703 314.1 789 133.1 699 46.47 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 173 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 17 19 19 19 e!6 e!5 e!4 e!3 e!4 e!4 e!3 e!3 e!4 e!2 e!3 e!2 ell e!2 e!2 ell e!2 e!2 6.4 5.8 5.4 4.9 6.9 9.1 7.2 10 13 19 23 28 21 15 9 7 7 9 11 14 16 19 23 27 38 56 83 124 183 249 162 87 47 28 41 71 97 15 19 21 .90 1.2 1.5 1.1 e.79 .41 .26 .26 .33 .43 .50 .57 .70 .79 .92 el. 3 el. 7 e2.6 e4.0 e5.7 e7.7 e3.6 1.5 .72 .41 .55 1.4 2.3 .33 .70 .77 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 13 12 12 11 15 20 16 10 12 13 13 13 18 24 27 27 26 21 16 13 13 14 14 21 23 20 17 15 14 11 8 8 8 8 10 12 17 34 86 194 147 78 45 40 37 35 33 32 30 17 9 4 5 9 11 12 .49 .35 .28 .23 .33 .48 .41 .32 .58 1.2 3.0 6.9 6.7 5.0 3.3 2.9 2.6 2.0 1.4 1.1 1.1 .64 .36 .24 .35 .50 .52 .49 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (HG/L) (TONS/DAY) TOTAL 375.7 45.94 469 43.77 15 17 17 16 15 15 16 16 16 16 16 16 18 19 20 18 19 16 23 16 11 10 10 8.6 7.8 8.6 9.3 9.2 9.4 8.7 9.0 441.6 MARCH 12 12 15 14 14 18 27 34 27 19 15 23 44 91 66 33 18 13 13 10 11 10 11 11 11 12 12 11 13 9 10 .50 .57 .69 .62 .62 .79 1.1 1.5 1.2 .84 .67 1.0 2.2 4.6 3.5 1.6 .92 .59 .86 .43 .34 .28 .31 .25 .24 .30 .30 .28 .34 .23 .25 27.92 e Estimated 174 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 8.3 7.9 7.9 7.8 7.6 7.6 5.5 4.3 4.8 5.0 5.1 5.2 5.2 5.1 4.8 4.4 4.3 6.0 7.6 7.4 7.3 5.7 5.3 5.4 5.3 5.3 5.1 4.0 3.2 3.2 APRIL 8 8 10 15 18 15 11 11 12 15 18 16 13 12 10 10 9 10 11 11 10 10 9 8 8 7 7 6 5 6 —— MAY .19 .18 .22 .31 .37 .32 .17 .13 .16 .21 .25 .23 .19 .16 .13 .12 .11 .17 .23 .23 .20 .16 .13 .13 .12 .11 .09 .07 .05 .06 —— 4.7 7.1 7.2 7.2 6.3 5.5 5.3 5.2 5.3 5.1 5.2 3.7 2.7 2.7 2.7 2.7 4.8 6.0 4.9 3.0 2.9 2.9 4.5 5.6 5.7 5.8 5.7 4.1 3.1 3.3 3.3 6 7 9 9 9 12 15 19 16 13 10 8 8 8 6 6 6 7 5 8 12 21 36 20 18 15 10 7 10 17 27 .08 .15 .18 .18 .16 .18 .22 .27 .23 .18 .14 .08 .06 .07 .05 .05 .09 .12 .07 .07 .09 .17 .44 .30 .27 .23 .16 .08 .09 .15 .23 3.3 8.5 9.6 6.6 6.5 6.5 6.5 6.8 4.9 3.1 3.1 3.0 4.5 5.3 5.7 4.8 3.4 3.3 3.3 5.2 6.6 6.7 4.3 3.3 3.4 3.6 3.7 3.7 3.8 3.8 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 20 8 8 9 8 8 10 12 12 9 8 6 7 7 8 8 8 9 11 12 13 8 6 5 6 6 3 3 4 4 .18 .21 .21 .16 .14 .15 .19 .22 .16 .08 .07 .05 .09 .11 .12 .11 .08 .08 .10 .17 .23 .16 .07 .05 .06 .06 .04 .03 .04 .05 TOTAL 171.6 5.20 144.2 4.84 146.8 3.47 RZO OB BAYAMON BASIN 50047560 RZO OB BAYAMON BELOW LACK) CZDRA , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 175 DISCHARGE DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR (CFS) 3.8 4.1 6.7 6.7 7.2 7.7 6.5 4.0 4.1 4.3 4.1 4.2 4.1 4.2 5.9 8.8 6.8 6.8 7.0 7.3 7.3 7.3 7.6 6.7 7.4 6.9 7.2 7.5 7.0 7.0 7.1 193.3 4635.8 MEAN CONCEN- TRATION DISCHARGE (MG/L) (TOMS/DAY) JULY MEAN DISCHARGE (CP8) 3.8 4.1 6.7 6.7 7.2 7.7 6.5 4.0 4.1 4.3 4.1 4.2 4.1 4.2 5.9 8.8 6.8 6.8 7.0 7.3 7.3 7.3 7.6 6.7 7.4 6.9 7.2 7.5 7.0 7.0 7.1 7 14 36 82 51 21 9 4 4 4 3 4 4 5 5 6 8 6 7 17 58 176 82 20 6 5 8 13 14 14 16 .08 .16 .65 1.5 .98 .44 .18 .05 .05 .05 .04 .05 .05 .06 .09 .13 .14 .12 .13 .35 1.1 3.5 1.7 .36 .13 .11 .17 .27 .28 .27 .32 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 7.1 7.3 7.3 7.8 7.3 7.2 7.6 7.5 7.7 8.1 7.2 7.1 7.1 8.7 6.7 7.2 7.0 7.1 8.0 7.2 7.1 7.8 7.1 8.1 7.5 8.5 8.4 7.1 8.7 8.4 8.8 15 16 16 17 22 32 46 48 45 43 41 38 37 40 45 49 28 13 7 8 16 34 69 140 256 134 43 18 19 17 17 .28 .32 .33 .36 .43 .61 .93 .96 .94 .94 .79 .74 .70 .95 .83 .96 .52 .27 .16 .17 .32 .71 1.3 3.1 5.3 3.2 .94 .35 .45 .38 .41 MEAN DISCHARGE (CFS) 8.7 10 14 14 13 11 8.8 10 11 11 8.6 7.0 5.8 5.8 5.9 7.2 8.0 8.0 8.1 8.2 8.5 8.7 8.5 8.1 8.0 8.1 8.5 8.2 8.0 8.2 MEAN CONCEN- TRATION (MG/L) SEPTEMBER 19 22 25 30 37 44 33 21 14 14 16 18 17 13 13 15 21 28 28 23 20 18 16 13 11 11 10 16 28 47 SEDXtfiENT DISCHARGE (TONS/DAY) .44 .61 .95 1.1 1.2 1.3 .78 .60 .42 .41 .38 .35 .27 .21 .20 .31 .44 .61 .60 .51 .46 .44 .37 .29 .25 .24 .24 .35 .61 1.1 13.51 683.01 235.7 28.65 266.9 16.04 176 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE SEP 1997 21... TIME 1626 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 8.6 671 15 80 84 88 DATE SEP 1997 21... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 89 91 97 98 99 100 100 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW XAQO CIDRA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 177 DATE OCT 1996 10... FEB 1997 12... MAR 14... MAY 28... TIME 1507 1608 1738 1100 DIS- CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 22 13 18 3.2 SEDI- MENT, SUS- PENDED (MG/L) (80154) 191 243 114 57 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 11 8.5 5.5 0.49 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 100 58 86 97 RIO DE BAYAMON BASIN 50047600 RIO DE BAYAHON NEAR AGUAS BUENAS, PR MATER-QUALITY RECORDS LOCATION.—Lat 18°14'39", long 66°08'39", at bridge on Highway 156, and 2.9 mi (4.7 km) west of Aguas Buenas plaza. DRAINAGE AREA.—18.5 mi 2 (47.9 km2 ). PERIOD OF RECORD.—Hater years 1958-65, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 08... FEB 1997 19... MAY 13... SEP 09... OCT 08 FEB 19 MAY 13 SEP 09 OCT DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1010 30 173 7.4 24.0 0.30 8.0 93 <10 K700 K1900 0820 27 289 6.5 21.5 1.7 7.6 85 <10 590 K1300 1320 9.2 336 8.3 27.0 0.55 8.2 105 <10 K91 580 1305 14 299 8.2 28.0 0.89 7.8 103 <10 230 300 ALKA- HARD- MAGNE- SODIUM POT AS- LINITY CHLO- DATE 1996 ... 1997 ... ... ... DATE 1996 08... FEB 19 MAY 13 09 OCT 08 FEB 19 MAY 13 SEP 09 1997 ... ... ... DATE 1996 ... 1997 . . . . . . NESS TOTAL (MG/L AS CACO3) (00900) 75 — 130 99 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.28 0.24 0.22 0.24 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 18 — 30 23 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 18 — 29 26 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.0 0.99 0.68 0.86 SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.4 — 14 10 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 134 — 203 175 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.5 4.4 3.0 3.8 SODIUM, DIS-' SOLVED (MG/L AS NA) (00930) 8.2 — 18 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 10.8 -- 5.06 6.62 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.070 0.030 0.030 <0.020 AD- SORP- TION RATIO (00931) 0.4 — 0.7 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 52 <1 <1 14 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 — 1.7 2.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.720 0.750 0.450 0.620 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 100 110 130 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.030 <0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) 0.5 — <0.5 *.. NITRO- GEN, NO2+N03 TOTAL (MG/L AS N) (00630) 0.750 0.750 0.460 0.630 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 8.2 — 11 6.6 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.010 0.020 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 3 -- 1 — RIDE, DIS- SOLVED (MG/L AS CL) (00940) 12 — 22 15 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.25 0.23 0.20 0.21 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 11 — K » non-ideal count DATE OCT 1996 08... FEB 1997 19... MAY 13... SEP 09... RIO DE BAYAMON BASIN 50047600 RIO DE BAYAMON NEAR AGUAS BUENAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 179 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 2700 100 <1 100 32 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 0.03 180 RIO DB BAYAMON BASIN 50047850 RIO BAYAMON NR BAYAMON, PR LOCATION.--Lat 18»20'08", long 66°08'13", Hydrologic Unit 21010005, on left bank, at rock <juarry near Highway 174, 1.3 ml (2.1 km) south of colonia Santa Rosa and 4.7 ml (7.6 km) south of Bayamon. DRAINAGE AREA.--41.8 mi 2 (108.3 km2 ). PERIOD OF RECORD.—September 1964 to October 1970, June 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 98 ft (30 m), from topographic map. REMARKS.—Records fair. Diversion to the Guaynabo water treatment plant, for municipal supply, made upstream from station (at Represa de San Juan). Flow is regulated by storage and release of water at Lago de Cidra (capacity 5,220 acre-ft), 10.5 mi (16.9 km) upstream. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR JUN JUL AUG SEP 1 23 35 2 e24 22 3 e48 28 4 28 22 5 22 22 6 21 19 7 19 21 8 18 20 9 18 29 10 17 52 11 17 57 12 23 100 13 21 131 14 21 40 15 18 23 16 18 19 17 18 50 18 18 28 19 17 19 20 17 20 21 17 34 22 17 170 23 17 121 24 17 139 25 16 106 26 50 55 27 47 43 28 59 54 29 61 47 30 48 115 31 23 —— TOTAL 798 1641 MEAN 25.7 54.7 MAX 61 170 MIN 16 19 AC -FT 1580 3250 CFSM .62 1.31 IN. .71 1.46 STATISTICS OF MONTHLY MEAN MEAN 30.2 43.9 MAX 129 174 (WY) 1991 1970 MIN 4.30 7.91 (WY) 1969 1965 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 79 68 48 37 29 e24 •22 •21 •21 e22 •25 •22 e21 •20 •20 •22 e21 •21 •20 •20 •21 •19 •20 •22 •22 •98 •36 •52 •78 •45 •36 1032 33.3 98 19 2050 .80 .92 •34 •47 •28 •28 •28 •23 •23 •23 e22 •20 •20 •20 e20 •20 21 22 22 24 33 37 248 366 184 239 163 60 29 25 27 20 17 1893 61.1 366 17 3750 1.46 1.68 57 45 21 25 23 21 21 20 20 16 16 18 19 •21 •17 •17 17 •17 el8 •18 •60 35 22 24 24 21 20 19 —— 672 24.0 60 16 1330 .57 .60 DATA FOR WATER YEARS 1964 41.2 263 1966 5.19 1968 FOR 36.4 159 1969 5.30 1968 21.9 75.3 1989 4.75 1965 19 20 26 23 29 20 20 22 20 17 17 16 16 15 13 13 12 12 11 11 11 10 9.9 9.8 10 9.8 9.4 10 24 13 11 479.9 15.5 29 9.4 952 .37 .43 - 1997 17.7 52.9 1990 3.58 1965 1996 CALENDAR YEAR 19743.8 53.9 8640 7.8 8.7 39160 1.29 17.57 56 18 12 Sep 10 Apr 2 Mar 27 10 12 14 13 13 12 12 12 11 11 10 9.9 9.7 9.5 9.3 9.5 9.6 9.6 9.3 9.4 12 10 9.6 9.7 10 9.0 9.9 11 12 12—— 321.0 10.7 14 9.0 637 .26 .29 13 12 19 14 9.0 8.7 8.1 8.1 8.3 8.0 7.9 7.7 8.1 8.1 8.0 8.7 8.3 7.6 7.2 8.5 8.4 7.8 14 18 13 13 10 9.6 9.3 9.8 9.6 310.8 10.0 19 7.2 616 .24 .28 9.4 9.0 8.9 8.0 7.4 6.8 6.7 7.8 8.1 7.8 7.5 6.9 7.2 6.9 7.2 •6.8 •6.5 •6.5 •17 •9.0 •7.2 •6.9 •6.9 •7.2 •7.5 •8.7 7.1 7.3 7.2 7.5 —— 234.9 7.83 17 6.5 466 .19 .21 7.8 6.6 6.0 5.9 5.9 6.4 5.8 6.1 6.2 6.0 5.7 6.2 6.1 5.6 5.5 •5.9 •7.2 •9.1 13 13 7.5 •7.1 •7.5 •7.5 8.1 6.8 6.7 5.8 5.7 5.8 7.3 215.8 6.96 13 5.5 428 .17 .19 5.6 5.0 27 37 6.4 5.5 5.3 5.2 5.3 6.0 11 7.6 7.4 9.6 14 9.9 12 12 7.7 7.1 7.2 41 13 35 67 9.9 9.1 8.0 7.5 9.1 9.9 423.3 13.7 67 5.0 840 .33 .38 9.2 11 9.9 9.8 11 12 11 9.8 10 11 9.9 14 27 42 14 11 9.9 9.9 9.8 9.0 11 43 28 71 17 26 14 12 12 11—— 506.2 16.9 71 9.0 1000 .40 .45 , BY WATER YEAR (WY) 21.0 72.7 1971 5.36 1965 FOR 1997 8527 23 366 5 5 685 5 16920 7 46 14 6 39.6 131 1966 4.85 1994 WATER YEAR .9 .4 Jan 22 . 0 Aug 2 .9 Jul 10 Jan 21 .95 Jan 21 .56 .59 .9 18.9 60.8 1970 3.68 1994 21.4 46.6 1970 4.01 1994 WATER 32. 59. 10. 8640 2. 2. 65000 29. 23730 . 10. 55 13 4. 40.4 137 1970 7.47 1994 YEARS 1964 8 7 9 Sep 2 Apr 4 Apr Sep 07 Sep 78 65 9 60.3 360 1996 6.02 1967 - 1997 1966 1994 10 1996 19 1965 14 1965 10 1996 10 1996 e Estimated 181 RIO DE BAYAMON BASIN 50047990 RIO GUAYNABO NEAR BAYAMON, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°22'32", long 66°07'59", at bridge on Highway 833, 0.2 mi (0.3 km) upstream from Rio de Bayamon, and 2.3 mi (3.7 km) southeast of Bayamon plaza. DRAINAGE AREA.—73.2 mi 2 (189.6 km») . PERIOD OF RECORD.—Water years 1958, 1964, 1971-73, 1976, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 08... TIME 1200 0815 1020 0815 SPE- CIFIC CON- DUCT- ANCE (US/CM) PH WATER WHOLE FIELD (STAND- ARD UNITS) TEMPER- ATURE WATER (DEG C) TUR- BID- ITY (NTU) OXYGEN, DIS- SOLVED (MG/L) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) COLI- FORM, FECAL, 0.45 UM-MF (COLS . / 100 ML) STREP- TOCOCCI FECAL, (COLS . PER 100 ML) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 428 463 508 540 7.3 6.6 6.7 6.9 27.5 23.5 28.0 27.5 6.0 4.5 8.3 5.8 3.7 4.5 4.1 1.7 47 52 52 22 23 11 52000 34000 K770 K60000 3400 3500 370 63000 DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 08... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS SO4) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 160 41 180 48 160 41 13 14 13 27 30 23 0.9 1 0.8 3.3 3.8 2.5 180 180 200 240 2.1 <0.5 11 12 15 31 38 24 DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 08... FLUO- SILICA, RIDE, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS AS F) SIO2) (00950) (00955) SOLIDS, RESIDUE SUM OF TOTAL CONSTI- AT 105 TUENTS, DEG. C, DIS- SUS- SOLVED FENDED (MG/L) (MG/L) (70301) (00530) 0.10 27 0.19 32 0.20 27 261 299 248 38 22 10 12 NITRO- NITRO- NITRO- GEN, GEN, GEN, NITRATE NITRITE NO2+NO3 TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L AS N) AS N) AS N) (00620) (00615) (00630) 0.310 0.090 0.400 0.760 0.080 0.840 0.650 0.110 0.750 0.110 0.043 0.150 NITRO- NITRO- GEN, GEN, AMMONIA ORGANIC TOTAL TOTAL (MG/L (MG/L AS N) AS N) (00610) (00605) 0.840 0.250 0.260 1.50 0.34 0.37 0.34 0.88 DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 08... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS NO3) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 1.2 0.62 0.59 2.4 1.6 1.5 1.3 2.6 7.0 6.5 6.0 11 0.190 0.200 0.230 0.410 <100 <100 60 50 K * non-ideal count Discharge measurement values not available due to ponded conditions. 11 182 RIO DE BAYAMON BASIN 50047990 RIO GUAYNABO NEAR BAYAMON, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 08... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 1100 670 460 <0.10 310 <0.10 <1 <1 <1 <1 20 <0.010 10 <0.010 <1 0.12 0.06 183 RIO DE BAYAMON BASIN 50048510 RIO DE BAYAMON AT FLOOD CHANNEL AT BAYAMON, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°24'29", long 66°09'04", at bridge on Highway 890, 1.0 mi (1.6 km) downstream from bridge on Highway 2, and 3.2 mi (5.1 km) above mouth. DRAINAGE AREA.—71.9 mi* (186.2km*). PERIOD OF RECORD.—Water years 1974 to current year. REMARKS.—Prior to 1979 sampling site was 0.8 mile (1.3 km) downstream but was changed because of flood channel construction. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 17... 0900 61 404 7.3 28.0 1.2 7.7 98 13 420 3100 MAR 1997 07... 1115 18 453 7.2 29.0 5.1 7.2 93 11 K630 320 MAY 12... 1215 9.5 468 7.1 29.5 17 8.0 105 <10 560 240 SEP 05... 1035 12 491 7.2 29.5 5.7 6.3 82 <10 2300 120 ALKA- DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 05... DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 05... DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 05... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 150 — 180 180 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — 0.17 0.14 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.37 0.63 0.43 0.40 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 40 — 45 49 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 25 -- 29 27 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.83 1.2 0.43 0.62 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 — 16 15 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 193 — 290 296 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 3.7 5.4 1.9 2.7 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 22 -- 25 26 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 32.0 -- 7.42 9.44 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.130 0.030 0.030 SODIUM AD- SORP- TION RATIO (00931) 0.8 — 0.8 0.8 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 6 <1 7 9 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — 1 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.9 -- 2.5 2.6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.390 0.550 -- 0.190 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 78 85 210 220 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.060 0.030 <0.010 0.030 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- 40 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.460 0.580 <0.020 0.220 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 13 — 14 15 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.170 0.200 0.020 0.070 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — 1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 30 — 33 31 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.20 0.43 0.41 0.33 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <io — <10 -- K - non-ideal count 184 RIO DB BAYAMON BASIN 50048510 RIO DE BAYAMON AT FLOOD CHANNEL AT BAYAMON, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 17... MAR 1997 07... MAY 12... SEP 05... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 230 1000 <1 200 490 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 0.02 0.04 PESTICIDE ANALYSES DATE MAY 1997 12... TIME 1215 PCB, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFILT RECOVER (UG/L) (39360) P,P'- DDE, TOTAL (UG/L) (39365) P,P'- DDT UNFILT RECOVER (UO/L) (39370) DI- AZINON, TOTAL (UO/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UG/L) (39388) <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 MAY 1997 12... HEPTA- ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) (39390) (39398) (39410) HEPTA- METH- CHLOR MALA- OXY- CHLOR, EPOXIDE LINDANE THION, CHLOR, TOTAL TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39420) (39340) (39530) (39480) METHYL PARA- THION, MIREX, TOTAL TOTAL (UG/L) (UG/L) (39600) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE MAY 1997 12... PARA- THION, TOTAL (UG/L) (39540) PCNS UNFILT RECOVER (UG/L) (39250) PER- THANE TOTAL (UG/L) (39034) TOX- APHENE, TOTAL (UG/L) (39400) <0.010 <0.100 <0.100 <1.00 TOTAL TRI- THION (UG/L) (39786) <0.010 2,4-D, TOTAL (UG/L) (39730) 2,4,5-T TOTAL (UG/L) (39740) 2, 4-DP TOTAL (UG/L) (82183) SILVEX, TOTAL (UG/L) (39760) 0.040 <0.010 <0.010 <0.010 18** RIO PUERTO NUEVO BASIN ***' 50048680 LAGO LAS CURIAS AT DAMSITE NEAR RIO PIEDRAS, PR LOCATION.—Lat 18°24'23", long 66°03'05", Hydrologic Unit 21010005 at Lago Las Curias Dam on Rio Piedras, 4.15 mi (6.67 km) south of University of Puerto Rico Tower, 1.6 mi (2.57 km) northwest from Escuela Jose F. Diaz and 0.8 mi (1.28 km) north of Escuela Cupey Alto. DRAINAGE AREA.—0.97 mi* (2.51 km2 ). ELEVATION RECORDS PERIOD OF RECORD.—April to September 1997. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Las Curias was completed in 1946. The reservoir has a capacity of 1,135 ac-ft (1.40 hm3 ) at spillway crest elevation 315.78 ft (96.25 m) for water supply. The dam is earthfill and has a crest elevation of 327.3 ft (99.75 m). Masonry parapet walls continous from abutment on each side of the 25 ft (7.62 m) wide crest. The dam is about 82.0 ft (25.0 m) high and 984.2 ft (300.0 m) long. The morning-glory inlet conduit spillway in located along the left abutment of the dam and has an uncontrolled capacity of about 5,000 ftVs (141.6 mVs) at reservoir elevation 321.5 ft (98.0 m) . This dam is operated by Puerto Rico Aqueduct and Sewer Authority. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximum elevation, 316.22 ft (96.38 m), May 21; minimum elevation, 315.48 ft (96.15 m), May 20. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 284.7 154 314.3 1,078 298.2 462 317.5 1,232 307.1 770 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 315.86 315.65 315.79 315.63 315.79 315.81 2 315.87 315.63 315.77 315.61 315.77 315.84 3 315.87 315.63 315.77 315.60 315.76 315.82 4 315.86 315.64 315.75 315.59 315.75 315.81 5 315.85 315.63 315.74 315.58 315.73 315.81 6 315.83 315.61 315.72 315.58 315.72 315.81 7 315.82 A A 315.57 315.70 315.79 8 315.81 315.60 A 315.57 315.72 315.79 9 315.80 A 315.69 315.57 315.70 315.78 10 315.79 315.58 315.67 315.55 315.76 315.77 11 315.80 A 315.70 315.57 315.75 315.75 12 315.80 A 315.69 315.56 315.78 315.78 13 315.79 A 315.67 315.54 315.90 315.95 14 315.78 A 315.66 315.52 315.86 315.87 15 315.77 315.53 315.64 315.52 315.82 315.84 16 315.76 315.53 315.63 315.54 315.83 315.83 17 315.74 315.52 315.61 315.52 315.86 315.82 18 315.74 315.51 315.60 315.54 315.82 315.80 19 315.73 315.49 315.60 315.55 315.81 315.79 20 315.74 315.77 315.59 315.82 315.81 315.79 21 315.73 315.93 315.58 315.81 315.90 315.79 22 315.72 315.84 315.56 315.80 315.91 315.82 23 315.72 315.82 315.58 315.78 315.85 315.85 24 315.71 315.85 315.62 315.77 315.91 315.85 25 315.69 315.84 315.61 315.78 315.85 315.84 26 27 28 29 30 31 MEAN 315.77 -— -— 315.65 315.80 315.82 MAX 315.87 --- —— 315.85 315.91 315.95 MIN 315.66 —— --- 315.52 315.70 315.75 A No gage-height record 315.68 315.69 315.68 315.67 315.66 ___ 315.82 315.82 315.81 315.80 315.79 315.79 315.56 A A A 315.64 315.78 315.77 315.80 315.78 315.85 315.81 315.83 315.82 315.80 315.80 315.79 315.82 315.87 315.85 315.84 315.88 315.84 —— 186 RIO PUERTO NUEVO BASIN 50048800 RIO PIEORAS NEAR RIO PIEORAS, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°22'15", long 66°03'40", at bridge on Winston Churchill Avenue in the El Senorial Housing area, 0.5 mi (0.8 km) west of Highway 176, and 2.5 mi (4.0 km) southwest of Rio Piedras plaza. DRAINAGE AREA.—8.17 mi 2 (20.9 km2 ). PERIOD OF RECORD.—Water years 1972 to current year. WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 15... FEE 1997 18... MAY 27... SEP 05... TIME 1100 0800 0845 0745 DIS- CHARGE, INST. CUBIC FEET PER SECOND SPE- CIFIC CON- DUCT- ANCE (US/CM) PH WATER WHOLE FIELD (STAND- ARD UNITS) TEMPER- ATURE WATER (DEG C) TUR- BID- ITY (NTU) OXYGEN, DIS- SOLVED (MG/L) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 9.9 446 7.1 28.0 2.0 3.9 49 21 52000 58000 11 404 6.8 22.5 3.2 6.3 71 10 5600 K18000 6.6 473 7.1 25.0 3.9 6.3 77 <10 K150000 27000 6.9 508 7.3 26.5 1.2 1.9 24 40 570000 460000 DATE OCT 1996 15... FEB 1997 18... MAY 27... SEP 05... HARD- NESS TOTAL (M6/L AS CACO3) (00900) CALCIUM DIS- SOLVED (M6/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS SO4) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 150 170 160 39 42 47 13 13 13 27 28 30 3.3 3.0 4.2 174 180 180 200 1.0 <0.5 18 18 17 34 33 36 DATE OCT 1996 15... FEB 1997 18... MAY 27... SEP 05... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — 0.14 0.16 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 32 — 33 29 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 271 283 277 290 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.22 8.41 4.91 5.38 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 10 3 10 11 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.700 0.940 — 0.260 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.120 0.100 — 0.056 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.820 1.00 — 0.310 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 2.30 0.430 — 6.20 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.77 0.29 — 2.1 DATE OCT 1996 15... FEB 1997 18... MAY 27... SEP 05... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS NO3) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 3.1 0.71 8.3 E = estimate K " non-ideal count 3.9 1.8 8.7 17 7.8 38 0.400 0.140 0.870 200 300 50 40 <1 <1 <1 <1 10 18 RIO PUERTO NUEVO BASIN 187 50048800 RIO PIEDRAS NEAR RIO PIEDRAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE IRON, TOTAL RECOV- ERABLE (UQ/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UQ/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UQ/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UQ/L AS HQ) (71900) SELE- NIUM, TOTAL (UQ/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UQ/L AS AQ) (01077) ZINC, TOTAL RECOV- ERABLE (UQ/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UQ/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 15... FEB 1997 18... MAY 27... SEP 05... 390 370 250 230 <0.10 <0.10 <1 <1 <1 <1 20 <0.010 <0.010 <1 0.62 0.03 PESTICIDE ANALYSES CHLOR- DATE TIME PCB, TOTAL (UQ/L) (39516) ALDRIN, TOTAL (UQ/L) (39330) DANE, TECH- NICAL TOTAL (UQ/L) (39350) P,P'- DDD UNFILT RECOVER (UQ/L) (39360) P,P'- DDE, TOTAL (UQ/L) (39365) P,P'- DDT UNFILT RECOVER (UQ/L) (39370) DI- AZINON, TOTAL (UQ/L) (39570) DI- ELDRIN TOTAL (UQ/L) (39380) ENDO- SULPAN, I TOTAL (UQ/L) (39388) MAY 1997 27... 0845 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 0.030 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UQ/L) (UQ/L) (39390) (39398) HEPTA- HEPTA- CHLOR CHLOR, EPOXIDE LINDANE TOTAL TOTAL TOTAL (UQ/L) (UQ/L) (UQ/L) (39410) (39420) (39340) MALA- THION, TOTAL (UQ/L) (39530) METH- OXY- CHLOR, TOTAL (UQ/L) (39480) METHYL PARA- THION, TOTAL (UQ/L) (39600) MIREX, TOTAL (UQ/L) (39755) MAY 1997 27... <0.010 <0.010 <0.010 <0.010 <0.010 0.010 <0.010 <0.010 <0.010 PARA- THION, DATE TOTAL (UQ/L) (39540) PCNS PER- TOX- TOTAL UNFILT THANE APBENE, TRI- 2,4-D, 2,4,5-T 2, 4-DP SILVEX, RECOVER TOTAL TOTAL THION TOTAL TOTAL TOTAL TOTAL (UQ/L) (UQ/L) (UQ/L) (UQ/L) (UQ/L) (UQ/L) (UQ/L) (UQ/L) (39250) (39034) (39400) (39786) (39730) (39740) (82183) (39760) MAY 1997 27... <0.010 <0.100 <0.100 <1.00 <0.010 0.010 <0.010 <0.010 <0.010 188 RIO PUERTO NUEVO BASIN 50049100 RIO FIEDRAS AT HATO REY, PR LOCATION.--Lat 18°24'34", long 66°04'10", Bydrologic Unit 21010005, at bridge on Avenida Pineiro near Expreso Las Americas (Luis A. Farre), and 0.8 mi (1.3 km) southwest of Hato Rey. DRAINAGE AREA.--15.4 mi 2 (39.9 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—June 1970 to December 1987 (discharge measurements only), 1972 to December 1982 (maximum discharge only), January 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 16 ft (5 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Mean daily discharge affected by sewage discharges (approximately 2.0 ftVs (0.06 mVs)), 20 ft (6 m) upstream from gaging station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV FEE JUL AUG 1 elOO 18 2 e90 12 3 e90 35 4 e51 18 5 48 115 6 e57 22 7 e51 11 8 33 37 9 32 16 10 84 41 11 33 11 12 24 62 13 86 612 14 76 53 15 29 50 16 23 137 17 19 166 18 19 116 19 18 22 20 12 21 21 28 13 22 14 461 23 17 194 24 13 206 25 17 82 26 125 42 27 47 68 28 366 84 29 80 36 30 31 188 31 36 —— TOTAL 1749 2949 MEAN 56.4 98.3 MAX 366 612 MIN 12 11 AC -FT 3470 5850 CFSM 3.71 6.47 IN. 4.28 7.22 68 65 33 60 32 28 26 25 23 32 106 24 18 17 16 50 14 13 12 12 40 20 15 104 9.7 158 175 215 273 184 75 1942.7 62.7 273 9.7 3850 4.12 4.75 STATISTICS OF MONTHLY MEAN DATA MEAN 66.3 76.8 MAX 134 235 (WY) 1991 1993 MIN 16.6 23.9 (WY) 1992 1991 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 50.3 168 1993 18.8 1992 FOR 44 154 83 33 38 18 13 48 16 9.5 90 39 22 41 19 17 11 27 27 18 232 311 203 199 68 17 11 30 47 27 15 1927.5 62.2 311 9.5 3820 4.09 4.72 278 108 54 59 66 35 47 59 109 40 41 85 68 45 22 42 33 39 43 22 103 65 22 112 91 59 31 25 ___ ___ ___ 1803 64.4 278 22 3580 4.24 4.41 FOR WATER YEARS 1972 46.9 97.4 1993 12.9 1973 42.3 86.9 1995 10.8 1992 27 43 45 55 97 24 34 48 28 16 15 32 18 11 10 9.4 10 52 ellO e45 e!5 e!6 e!2 e!2 e!3 e!6 n9.3 52 121 41 22 1058.7 34.2 121 9.3 2100 2.25 2.59 - 1997 37.8 78.5 1972 11.5 1994 1996 CALENDAR YEAR 27238.8 74.4 4550 9.5 12 54030 4.90 66.66 151 29 12 Sep 10 Apr 2 Feb 27 21 28 31 21 23 17 18 el7 e!5 e!5 el5 el6 e!5 e!5 el4 e!5 e!5 e!4 e!5 e!5 el4 el3 e!5 el8 18 18 27 20 20 20 ___ 538 17.9 31 13 1070 1.18 1.32 18 13 35 18 13 29 15 13 18 14 13 12 40 31 18 40 12 9.5 9.5 203 284 78 26 83 117 38 15 18 13 11 11 1268.0 40.9 284 9.5 2520 2.69 3.10 51 21 16 12 12 12 12 12 12 11 92 21 16 16 16 14 12 12 17 16 11 10 125 87 35 16 14 16 15 42 ___ 774 25.8 125 10 1540 1.70 1.89 16 11 11 11 29 48 12 25 12 11 17 19 10 10 9.6 80 13 48 80 518 150 73 35 28 143 30 28 90 24 138 151 1880.6 60.7 518 9.6 3730 3.99 4.60 31 16 29 17 19 18 15 122 36 57 19 109 218 152 62 70 133 59 15 13 161 396 112 172 93 35 34 17 12 11 127 2380 76.8 396 11 4720 5.05 5.82 18 197 25 33 14 16 19 18 16 15 13 18 182 110 53 64 17 17 17 14 26 39 109 50 9.5 86 53 18 196 62—— 1524.5 50.8 197 9.5 3020 3.34 3.73 , BY WATER YEAR (WY) 56.4 150 1972 13.6 1995 FOR 1997 19795 54 612 9 12 6690 18 39260 3 48 126 27 12 45.8 97.5 1992 4.12 1972 WATER YEAR .0 .2 Nov 13 .3 Mar 27 Jun 4 Nov 22 .66 Nov 22 .57 .45 42.3 81.9 1995 20.0 1994 49.1 97.4 1993 12.8 1994 WATER 54 84 28 4550 1 1 10500 22 39190 3 48 121 22 9 57.1 84.2 1988 20.2 1993 YEARS 1972 .1 .0 .7 Sep .2 Jun .2 Jul Sep . 11 Sep .56 .36 .6 88.4 261 1996 26.3 1972 - 1997 1993 1994 10 1996 28 1972 5 1972 10 1996 10 1996 e Estimated 189 RIO PUERTO NUEVO BASIN 50049100 RIO PIEDRAS AT HATO REY, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°24'34", long 66°04'10", at bridge on Avenida Piniero at Expreso Las Americas, and 0.8 mi (1.3 km) southwest of Hato Rey. DRAINAGE AREA.--15.4 mi* (39.9 km 1 ). PERIOD OF RECORD.—Water years 1971 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 1996 30... FEB 1997 18... MAY 27... SEP 08... DATE OCT 1996 30... FEB 1997 18... MAY 27... SEP 08... OCT 1996 30... FEB 1997 18... MAY 27... SEP 08... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1045 22 390 6.5 27.5 2.8 5.2 65 11 230000 63000 1200 22 414 6.7 24.5 3.7 5.7 68 17 27000 3800 1105 13 465 7.0 29.0 4.6 5.0 65 16 39000 4100 1155 16 HARD- NESS TOTAL (MG/L AS CAC03) (00900) 140 — 160 170 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.30 — 0.15 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.6 2.0 1.3 3.1 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 39 — 44 47 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 24 — 27 27 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.6 2.9 2.3 3.6 485 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 10 — 11 12 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 251 — 285 268 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 0.62 13 10 16 7.1 30.0 2 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 26 — 28 29 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 15.0 — 10.4 11.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.200 0.310 0.170 0.350 SODIUM AD- SORP- TION RATIO (00931) 1 — 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 13 1 13 2 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ .9 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.5 — 3.1 3.4 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.800 0.780 0.840 0.270 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 __ 4.2 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 175 180 200 200 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.100 0.120 <0.00 0.230 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 — 20 — 55 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.900 0.900 0.970 0.500 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — 12 K170000 23000 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 15 — 18 23 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.590 1.50 0.720 2.10 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 28 — 33 29 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.6 0.49 0.62 1.0 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K » non-ideal count 190 RIO PUERTO NUEVO BASIN 50049100 RIO PIEDRAS AT HATO REY, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 30... FEE 1997 18... MAY 27... SEP 08... 600 370 <1 <1 80 50 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 0.17 0.11 191 RIO PUERTO NUEVO BASIN 50049820 LACUNA SAN JOSE NO. 2 AT SAN JUAN, PR HATER-QUALITY RECORDS LOCATION.—Lat 18°25'46", long 66°02'10", 0.2 mi (0.3 km) east of Cano de Martin Pefia, and 650 ft (200 m) south of Isla Guachinango. DRAINAGE AREA.—Indeterminate. PERIOD OF RECORD.—Hater years 1974 to current year. HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PH OXYGEN, COLI- ALKA- RESIDUE SPE- WATER TRANS- DIS- FORM, STREP- LINITY TOTAL CIFIC WHOLE PAR- SOLVED FECAL, TOCOCCI HAT WH AT 105 CON- FIELD TEMPER- ENCY OXYGEN, (PER- 0.45 FECAL, TOT PET DEG. C, DUCT- (STAND- ATURE (SECCHI DIS- CENT UM-MF (COLS. FIELD SUS- DATE TIME ANCE ARD WATER DISK) SOLVED SATUR- (COLS./ PER MG/L AS FENDED (US/CM) UNITS) (DEG C) (IN) (MG/L) ATION) 100 ML) 100 ML) CACO3 (MG/L) (00095) (00400) (00010) (00077) (00300) (00301) (31616) (31679) (00410) (00530) OCT 1996 21... 1030 14900 8.3 30.0 11.0 4.5 58 2300 2100 57 17 MAR 1997 06... 0945 16000 8.4 25.5 18.0 9.2 90 30000 540 95 13 JUN 23... 1000 30000 8.7 29.5 15.0 9.0 117 4600 720 120 13 SEP 09... 1000 24000 8.3 31.0 9.00 10.2 137 4500 4900 121 11 NITRO- DATE OCT 1996 21... MAR 1997 06... JUN 23... SEP 09... NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) — <0.010 0.400 0.020 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) •eO.010 0.020 0.020 0.024 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) <0.020 <0.020 <0.020 0.050 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.020 0.050 0.080 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.6 1.5 1.3 2.2 GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.6 1.7 1.5 2.3 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.6 1.7 1.5 2.4 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 7.2 7.5 6.0 10 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.230 0.140 0.290 0.360 CARBON, ORGANIC TOTAL (MG/L AS C) (00680) 9.8 7.4 8.2 13 192 RIO PUERTO NUEVO BASIN 50049920 BAHIA DE SAN JUAN NO. 5 AT SAN JUAN, PR WATER-QUALITY RECORDS LOCATION--Lat 18°26'37", long 66°05'11", 0.4 mi (0.6 km) west of Puente de la Constitucion, and 0.5 mi (0.8 km) south from U.S. Naval Reservation. DRAINAGE--Indeterminate. PERIOD OF RECORD--Water years 1974 to present. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PH OXYGEN, COLI- ALKA- RESIDUE SPE- WATER TRANS- DIS- FORM, STREP- LINITY TOTAL CIFIC WHOLE PAR- SOLVED FECAL, TOCOCCI WAT WH AT 105 CON- FIELD TEMPER- ENCY OXYGEN, (PER- 0.45 FECAL, TOT FET DEG. C, DUCT- (STAND- ATURE (SECCHI DIS- CENT UM-MF (COLS. FIELD SUS- DATE TIME ANCE ARD WATER DISK) SOLVED SATUR- (COLS./ PER MG/L AS FENDED (US/CM) UNITS) (DEG C) (IN) (MG/L) ATION) 100 ML) 100 ML) CACO3 (MG/L) (00095) (00400) (00010) (00077) (00300) (00301) (31616) (31679) (00410) (00530) OCT 1996 21... 1145 40000 7.9 30.5 23.0 2.4 31 570000 4300 39 17 MAR 1997 06... 1100 32000 7.3 26.6 22.0 0.89 10 4500000 240000 160 30 JUN 23... 1200 >50000 7.6 29.0 28.0 6.6 85 K91 230 160 24 SEP 09... 1140 28000 7.6 33.0 13.0 9.8 73 2600 79000 170 32 NITRO- DATE OCT 1996 21... MAR 1997 06... JUN 23... SEP 09... NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) <0.010 -- 0.310 0.020 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.010 0.170 0.014 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) <0.020 <0.020 <0.020 0.030 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 1.40 8.70 3.00 0.600 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.83 1.8 0.45 1.6 GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 2.2 10 3.4 2.2 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.3 10 3.9 2.3 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 10 46 17 10 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.280 1.30 0.590 0.220 CARBON, ORGANIC TOTAL (MG/L AS C) (00680) 7.2 13 9.6 8.4 193 ATLANTIC OCEAN / L-Drc^noge bouftdar . vjwnrnwf vvn A 0509 AND NUMBER ETERS 0 222 WELL AND WELL NUMBER Figure 19.--Rfo Grande de Lofza basin. 194 RIO GRANDE DE LOIZA BASIN 50050300 QUEBRADA BLASINA NEAR CAROLINA, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°23'27", long 65°58'28", at bridge on Highway 3, 1.4 mi (2.3 km) south of Valle Arriba Heights housing area, and 1.2 mi (1.9 km) west-southwest of Carolina plaza. DRAINAGE AREA.—2.96 mi 2 (7.67 km2 ). PERIOD OF RECORD.--Water years 1973 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1300 6.8 526 7.1 28.0 4.4 5.7 72 <10 27000 2700 1300 7.6 495 6.5 24.5 2.2 5.9 70 13 49000 310000 1145 2.7 625 7.0 28.0 1.2 3.6 46 13 32000 71000 1200 4 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 200 — 28 160 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 -- <0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.73 0.90 3.4 0.89 .2 505 7 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 64 — 6.3 49 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 28 — 17 22 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.1 2.2 3.9 2.2 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 10 — 3.0 8.0 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 305 -- 160 253 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 9.2 9.7 17 9.5 .3 28 SODIUM, pis- SOLVED (MG/L AS NA) (00930) 31 — 7.4 29 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 5.56 — 1.17 2.87 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.120 0.200 0.590 0.200 .5 3. SODIUM AD- SORP- TION RATIO (00931) 1 — 0.6 0.8 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 9 3 <1 7 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — 1 __ 2 5. POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.7 — 0.62 4.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 1.00 0.310 1.10 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — 4 70 <10 5500 K1600 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 190 200 190 210 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.230 0.260 0.170 0.170 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 60 — 70 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 1.40 1.30 0.480 1.30 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 17 — 2.0 34 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.560 0.590 3.00 0.390 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 37 — 9.6 33 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.31 0.45 0.50 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K » non-ideal count RIO GRANDE DE LOIZA BASIN 50050300 QUEBRADA BLASINA NEAR CAROLINA, PR—Continued MATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... 420 470 MANGA- IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L TOTAL RECOV- ERABLE (UG/L MERCURY SILVER, ZINC, TOTAL SELE- TOTAL TOTAL RECOV- NIUM, RECOV- RECOV- CYANIDE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 <1 170 430 <0.10 <0.10 <1 <1 <1 <1 20 <0.010 <0.010 <1 METHY- TtffNE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 0.06 0.07 195 196 RIO GRANDE DE LOIZA BASIN 50050900 RIO GRANDE DE LOIZA AT QUEBRADA ARENAS, PR LOCATION.--Lat 18°07'10", long 65°59'22", Hydrologic Unit 21010005, at intersection of Highways 181 and 9990, 0.2 mi (0.3 km) upstream from confluence with Rio Emajagua and about 7.1 mi (11.4 km) southwest of San Lorenzo. DRAINAGE AREA.—6.00 mi 2 (15.54 km2 ). PERIOD OF RECORD.--October 1977 to current year. GAGE.—Water-stage recorder. Elevation of gage is 640 ft (195 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES NOV JAN APR JUN JUL AUG SEP 1 29 49 2 e30 31 3 e45 19 4 29 32 5 26 23 6 e26 25 7 26 53 8 e25 23 9 33 41 10 62 21 11 39 59 12 27 205 13 24 128 14 28 35 15 40 27 16 25 23 17 21 21 18 23 20 19 22 39 20 20 29 21 19 44 22 19 48 23 18 35 24 18 e24 25 17 21 26 20 20 27 20 19 28 19 19 29 18 19 30 17 22 31 19 TOTAL 804 1174 MEAN 25.9 39.1 MAX 62 205 MIN 17 19 AC-FT 1590 2330 CFSM 4.32 6.52 IN. 4.98 7.28 STATISTICS OF MONTHLY MEAN MEAN 39.6 44.4 MAX 123 122 (WY) 1986 1988 MIN 13.1 8.34 (WY) 1990 1990 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 19 18 17 17 17 16 17 15 15 15 26 15 14 14 14 14 13 13 12 12 12 12 12 13 14 13 12 12 62 28 16 519 16.7 62 12 1030 2.79 3.22 DATA 25.0 55.2 1988 6.65 1990 13 12 12 12 12 11 11 11 11 11 111 14 11 10 9.7 9.5 9.3 8.9 9.0 11 19 71 14 14 12 13 10 11 9.8 11 10 514.2 16.6 111 8.9 1020 2.76 3.19 116 100 25 18 29 28 20 18 29 19 25 23 41 29 22 22 18 18 17 17 25 22 36 19 18 50 18 16 --. --. —— 838 29.9 116 16 1660 4.99 5.20 FOR WATER YEARS 1978 19.4 56.1 1992 8.16 1990 19.0 38.0 1982 6.36 1979 15 15 15 15 14 14 13 15 13 12 12 13 14 15 19 15 12 12 11 10 9.9 9.7 9.1 8.7 8.4 8.3 8.2 9.0 8.5 7.6 8.8 370.2 11.9 19 7.6 734 1.99 2.30 - 1997 13.8 34.4 1996 5.07 1979 FOR 1996 CALENDAR YEAR 19708 53.8 3740 10 11 39090 8.97 122.19 98 24 13 Sep 10 May 28 May 25 7.3 333 37 15 12 11 10 10 9.8 9.5 9.4 9.3 9.7 9.2 8.8 8.5 8.5 8.3 8.2 8.1 8.1 8.0 7.9 7.7 7.7 7.6 7.5 7.4 7.3 7.2 --- 619.0 20.6 333 7.2 1230 3.44 3.84 7.0 6.9 6.9 7.0 6.8 6.6 7.6 7.8 7.3 23 12 17 14 12 13 12 17 12 9.8 9.7 9.6 9.4 8.5 8.7 10 9.0 17 18 32 22 13 372.6 12.0 32 6.6 739 2.00 2.31 15 42 64 e24 e22 e23 e20 e!8 e!7 e!6 e!6 e!6 e26 e20 e!5 ell e!2 e!2 ell e!2 11 9.8 11 11 9.6 10 9.2 8.7 8.3 8.0 --- 508.6 17.0 64 8.0 1010 2.83 3.15 7.8 7.5 7.4 7.5 9.9 11 8.8 9.8 10 8.3 7.7 8.2 13 8.0 7.7 14 13 9.9 27 47 145 35 48 24 20 20 17 164 28 64 30 838.5 27.0 164 7.4 1660 4.51 5.20 22 19 18 18 17 16 16 17 20 69 35 29 23 20 21 27 25 110 27 21 21 352 46 126 46 31 63 32 31 26 44 1388 44.8 352 16 2750 7.46 8.61 26 26 22 21 20 19 18 19 18 17 16 16 16 18 33 17 16 21 16 15 71 169 48 40 24 59 28 22 24 66 —— 941 31.4 169 15 1870 5.23 5.83 , BY WATER YEAR (WY) 13.7 27.1 1985 4.64 1979 FOR 1997 8887 24 352 6 6 3620 9 6 17630 4 55 41 17 8 30.3 77.5 1985 9.56 1988 WATER YEAR .1 .3 Aug 22 .6 May 6 .9 Apr 30 Apr 2 .84 Apr 2 .3 May 5 .06 .10 .3 38.7 122 1979 11.3 1985 37.6 92.3 1993 12.5 1986 WATER 30 54 14 3740 3 3 44000 25 2 21880 5 68 50 15 7 33.9 90.0 1979 9.30 1991 YEARS 1978 - .2 .1 .5 Sep 10 .1 May 7 .6 May 1 Sep 10 .93 Sep 10 .8 May 5 .03 .39 .1 46.9 202 1996 11.8 1981 1997 1996 1990 1996 1979 1979 1996 1996 1979 e Estimated 197 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR LOCATION.--Lat 18°09'40", long 65°58'58", Hydrologic Unit 21010005, 0.1 mi (0.2 km) upstream from bridge on Highway 181, and 2.8 mi (4.5 km) southwest of San Lorenzo. DRAINAGE AREA. —3.25 mi* (8.42 tan1 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—October 1984 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 459 ft (140 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC JAN FEB MAR JUL AUG SEP 1 8.7 9.4 2 16 13 3 7.1 7.5 4 6.3 6.7 5 6.2 6.7 6 6.2 6.6 7 6.6 17 8 6.7 18 9 13 14 10 25 9.9 11 15 18 12 12 44 13 10 34 14 9.2 20 15 9.3 16 16 9.4 14 17 8.5 14 18 8.2 12 19 8.5 17 20 8.6 14 21 7.8 12 22 7.9 10 23 7.9 12 24 7.3 11 25 7.2 9.0 26 8.2 7.7 27 13 7.0 28 9.9 7.3 29 8.9 6.4 30 7.5 7.1 31 6.9 TOTAL 293.0 401.3 MEAN 9.45 13.4 MAX 25 44 MIN 6.2 6.4 AC-FT 581 796 CFSM 2.91 4.12 IN. 3.35 4.59 6.2 5.6 4.9 4.7 4.3 4.5 9.1 5.2 4.4 4.4 28 12 8.9 7.5 7.2 6.9 5.7 5.1 4.9 4.8 4.6 4.5 4.4 4.6 6.4 4.4 4.5 4.2 7.4 11 4.7 205.0 6.61 28 4.2 407 2.03 2.35 4.0 3.8 3.7 3.7 3.6 3.5 3.3 3.3 3.2 3.1 9.0 3.8 3.4 3.0 3.0 3.0 2.8 2.6 3.0 4.6 12 24 6.4 4.4 3.9 3.6 3.0 7.4 4.1 3.5 3.4 149.1 4.81 24 2.6 296 1.48 1.71 16 17 9.2 5.8 9.7 7.5 6.3 5.1 14 5.5 6.9 9.6 11 9.9 6.3 5.0 4.4 4.0 3.9 3.9 4.8 4.7 11 4.4 4.6 4.6 4.0 3.8 -__ —— 202.9 7.25 17 3.8 402 2.23 2.32 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1984 MEAN 10.0 15.0 MAX 47.8 36.9 (WY) 1986 1985 MZN 2.75 2.49 (WY) 1993 1990 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 6.80 30.1 1988 1.49 1990 FOR 4.81 9.94 1992 1.74 1995 4.20 8.21 1989 1.32 1985 3.6 3.6 3.8 3.8 3.6 3.3 3.1 3.2 3.4 3.2 2.9 2.9 2.9 2.9 4.1 3.4 3.0 3.2 3.0 2.7 2.6 2.6 2.5 2.5 2.3 2.3 2.2 2.2 2.3 2.3 2.4 91.8 2.96 4.1 2.2 182 .91 1.05 - 1997 3.93 20.7 1989 1.64 1993 1996 CALENDAR YEAR 3797.7 10.4 326 1.3 1.5 7530 3.19 43.47 21 6.0 1.7 Sep 10 Apr 2 Mar 27 2.3 24 13 4.0 3.1 2.6 2.4 2.4 2.3 2.2 2.2 2.2 2.8 2.2 2.0 1.9 2.0 2.0 2.0 1.9 1.9 1.9 1.8 2.1 1.9 1.6 1.7 1.8 1.8 1.8 —— 97.8 3.26 24 1.6 194 1.00 1.12 1.8 1.6 1.4 1.3 1.3 1.4 1.4 1.8 2.0 3.7 3.0 3.3 2.3 2.2 3.3 3.2 12 3.1 2.5 2.8 2.6 2.1 1.9 1.9 1.9 1.9 3.4 5.0 3.3 3.6 3.1 86.1 2.78 12 1.3 171 .85 .99 2.7 4.6 7.3 4.3 3.8 4.0 3.5 3.1 3.0 2.7 2.7 2.7 4.3 3.4 2.6 1.9 2.0 2.0 1.9 2.0 1.9 2.0 2.6 2.7 1.8 1.8 1.6 1.5 1.5 1.5 —— 83.4 2.78 7.3 1.5 165 .86 .95 1.6 1.3 1.1 1.1 2.2 12 3.9 1.9 2.0 1.3 1.2 1.1 1.2 1.1 1.1 2.2 2.5 2.4 1.9 9.7 34 18 5.6 4.3 2.0 1.7 1.3 7.0 2.5 3.8 2.4 135.4 4.37 34 1.1 269 1.34 1.55 1.9 1.4 1.6 2.6 2.0 1.7 1.4 1.7 1.7 2.6 3.9 2.6 2.3 1.8 1.6 2.5 2.5 5.1 4.1 2.6 4.9 39 12 el02 21 8.4 23 15 7.4 5.5 17 302.8 9.77 102 1.4 601 3.01 3.47 6.6 6.0 3.8 3.0 2.5 2.2 2.1 5.3 3.5 2.1 1.7 2.9 2.4 7.1 11 3.6 2.8 11 4.0 3.3 12 17 23 28 12 18 9.2 5.1 4.1 6.6 —— 221.9 7.40 28 1.7 440 2.28 2.54 , BY WATER YEAR (WY) 2.32 4.88 1989 .75 1994 FOR 1997 2270 6 102 1 1 1530 8 4500 1 25 13 3 1 6.72 31.5 1985 .62 1994 WATER YEAR .5 .22 Aug 24 .1 Jul 3 .3 Jul 9 Aug 24 .76 Aug 24 .96 Jul 15 .91 .99 .8 .8 6.24 21.3 1987 2.12 1994 6.31 15.0 1993 2.02 1986 WATER 6. 12. 2. 457 . . 7610 14. . 5030 2. 29. 12 2. 1. 7.15 20.2 1988 1.95 1994 YEARS 1984 - 94 3 50 Dec 7 33 May 20 37 Apr 26 Sep 10 64 Sep 10 30 May 21 13 00 6 0 9.67 27.7 1996 1.36 1990 1997 1988 1990 1987 1994 1994 1996 1996 1994 e Estimated 198 RIO GRANDE DB LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1985 to 1986 and water year 1989 to current year. PERIOD OF DAILY RECORD.-- SUSPENDBD-SBDIHENT DISCHARGE: October 1984 to September 1986 and from October 1989 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1989. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 7,300 mg/L Oct. 06, 1985; Minimum daily mean, <1 mg/L several days in 1996. SEDIMENT LOADS: Maximum daily mean, 4,940 tons (4,480 tonnes) May 17, 1985; Minimum daily mean, <0.01 ton (<0.01 tonne) several days. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 1,260 mg/L August 24, 1997; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 1,270 tons (1,150 tonnes) August 24, 1997; Minimum daily mean, 0.01 ton (0.01 tonnes) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 8.7 16 7.1 6.3 6.2 6.2 6.6 6.7 13 25 15 12 10 9.2 9.3 9.4 8.5 8.2 8.5 8.6 7.8 7.9 7.9 7.3 7.2 8.2 13 9.9 8.9 7.5 6.9 8 75 32 14 13 12 12 15 55 124 17 8 5 4 5 5 16 79 43 27 6 5 .19 9.5 .63 .25 .21 .21 .22 .26 2.7 8.5 .73 .25 .15 .10 .12 .12 .10 .09 .09 .09 .09 .09 .09 .08 .08 .49 3.3 1.3 .68 .13 .09 NOVEMBER 9.4 13 7.5 6.7 6.7 6.6 17 18 14 9.9 18 44 34 20 16 14 14 12 17 14 12 10 12 11 9.0 7.7 7.0 7.3 6.4 7.1 —— 6 68 37 35 35 35 92 112 68 25 80 247 149 33 11 62 68 12 78 35 20 13 12 30 15 7 5 6 7 7 .15 2.8 .74 .64 .63 .62 5.9 7.3 2.8 .66 5.7 35 16 1.9 .47 2.5 2.9 .39 4.1 1.4 .61 .35 .38 1.1 .39 .15 .10 .12 .12 .14 —— DECEMBER 6.2 5.6 4.9 4.7 4.3 4.5 9.1 5.2 4.4 4.4 28 12 8.9 7.5 7.2 6.9 5.7 5.1 .9 .8 .6 .5 .4 .6 .4 .4 .5 .2 7.4 11 4.7 7 8 16 25 13 6 47 13 3 3 327 5 2 2 2 2 4 8 11 12 7 4 2 2 10 6 6 6 28 63 17 .12 .12 .21 .32 .15 .07 1.4 .18 .04 .04 79 .17 .05 .04 .04 .04 .06 .11 .14 .16 .09 .05 .03 .03 .23 .07 .07 .07 .79 2.2 .22 293.0 30.93 401.3 96.06 205.0 86.31 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 199 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) JANUARY 4.0 3.8 3.7 3.7 3.6 3.5 3.3 3.3 3.2 3.1 9.0 3.8 3.4 3.0 3.0 3.0 2.8 2.6 3.0 4.6 12 24 6.4 4.4 3.9 3.6 3.0 7.4 4.1 3.5 3.4 11 10 12 14 13 13 11 5 2 2 62 10 3 5 10 5 2 2 3 3 38 173 32 9 8 10 12 50 9 4 3 .12 .11 .12 .14 .13 .12 .10 .04 .02 .02 2.4 .10 .03 .04 .09 .04 .02 .02 .02 .04 2.2 19 .61 .10 .09 .10 .10 1.8 .11 .04 .03 MEAN DISCHARGE (CFS) CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY 16 17 9.2 5.8 9.7 7.5 6.3 5.1 14 5.5 6.9 9.6 11 9.9 6.3 5.0 4.4 4.0 3.9 3.9 4.8 4.7 11 4.4 4.6 4.6 4.0 3.8 82 100 17 4 49 43 28 26 81 43 30 50 64 31 24 10 4 3 2 4 7 7 48 10 13 18 9 4 6.2 7.4 .49 .07 3.2 1.0 .53 .36 4.9 .65 .66 3.1 2.2 .91 .42 .13 .05 .03 .03 .04 .09 .09 2.2 .12 .16 .23 .10 .04 DISCHARGE (CFS) 3.6 3.6 3.8 3.8 3.6 3.3 3.1 3.2 3.4 3.2 2.9 2.9 2.9 2.9 4.1 3.4 3.0 3.2 3.0 2.7 2.6 2.6 2.5 2.5 2.3 2.3 2.2 2.2 2.3 2.3 2.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 3 2 2 6 13 13 12 12 11 10 10 10 14 19 24 10 3 3 3 2 2 4 6 10 11 10 9 42 33 21 14 .03 .02 .03 .06 .12 .12 .10 .10 .10 .09 .08 .08 .11 .15 .28 .09 .03 .03 .02 .02 .02 .03 .04 .06 .07 .06 .05 .25 .20 .13 .09 TOTAL 149.1 27.90 202.9 35.40 91.8 2.66 200 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAOUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 2.3 24 13 4.0 3.1 2.6 2.4 2.4 2.3 2.2 2.2 2.2 2.8 2.2 2.0 1.9 2.0 2.0 2.0 1.9 1.9 1.9 1.8 2.1 1.9 1.6 1.7 1.8 1.8 1.8 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 13 134 86 37 25 17 14 21 30 20 14 13 14 15 24 33 20 12 13 14 16 18 16 6 2 2 2 3 8 19 .08 29 4.4 .40 .22 .12 .09 .14 .18 .12 .08 .08 .10 .09 .13 .17 .10 .06 .07 .07 .08 .09 .08 .03 .01 .01 .01 .01 .04 .09 MEAN DISCHARGE (CFS) 1.8 1.6 1.4 1.3 1.3 1.4 1.4 1.8 2.0 3.7 3.0 3.3 2.3 2.2 3.3 3.2 12 3.1 2.5 2.8 2.6 2.1 1.9 1.9 1.9 1.9 3.4 5.0 3.3 3.6 3.1 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 7 2 2 2 2 2 2 6 12 20 10 5 3 3 11 35 78 11 3 3 4 3 3 3 2 1 11 36 17 32 27 .04 .01 .01 .01 .01 .01 .01 .03 .06 .22 .08 .05 .02 .02 .09 .31 4.3 .10 .02 .03 .03 .02 .01 .01 .01 .01 .27 .51 .16 .31 .23 i TO aEPTrln MEAN DISCHARGE (CFS) 2.7 4.6 7.3 4.3 3.8 4.0 3.5 3.1 3.0 2.7 2.7 2.7 4.3 3.4 2.6 1.9 2.0 2.0 1.9 2.0 1.9 2.0 2.6 2.7 1.8 1.8 1.6 1.5 1.5 1.5 BER 1997 MEAN CONCEN- TRATION (MO/L) JUNE 20 53 42 9 3 2 2 2 2 2 2 2 6 2 4 8 9 8 6 3 2 1 13 14 3 6 14 8 4 2 SEDIMENT DISCHARGE (TONS/DAY) .14 .75 .91 .11 .04 .02 .02 .02 .02 .01 .01 .01 .09 .02 .03 .04 .05 .04 .03 .02 .01 .01 .11 .11 .01 .03 .06 .03 .02 .01 TOTAL 97.8 36.15 86.1 7.00 83.4 2.78 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAQUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 201 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 1.6 1.3 1.1 1.1 2.2 12 3.9 1.9 2.0 1.3 1.2 1.1 1.2 1.1 1.1 2.2 2.5 2.4 1.9 9.7 34 18 5.6 4.3 2.0 1.7 1.3 7.0 2.5 3.8 2.4 TOTAL 135.4 YEAR • 2270.5 Estimated MEAN CONCEN- SEDIMENT TRATZON DISCHARGE (MO/L) (TONS/DAY) JULY 1.6 1.3 1.1 1.1 2.2 12 3.9 1.9 2.0 1.3 1.2 1.1 1.2 1.1 1.1 2.2 2.5 2.4 1.9 9.7 34 18 5.6 4.3 2.0 1.7 1.3 7.0 2.5 3.8 2.4 3 4 2 3 16 75 17 10 25 19 11 9 7 6 7 8 4 9 28 118 189 79 97 30 10 7 6 80 5 33 18 .01 .01 .01 .01 .10 3.1 .20 .05 .13 .07 .04 .03 .02 .02 .02 .04 .03 .09 .15 3.8 19 4.8 1.8 .56 .05 .03 .02 3.0 .04 .39 .12 37.74 1770.08 MEAN DISCHARGE (CFS) 1.9 1.4 1.6 2.6 2.0 1.7 1.4 1.7 1.7 2.6 3.9 2.6 2.3 1.8 1.6 2.5 2.5 5.1 4.1 2.6 MEAN CONCEN- SEDIMENT TRATZON DISCHARGE (MO/L) (TONS/DAY) AUGUST 302.8 6 7 9 10 3 1 4 10 11 9 7 3 1 1 1 1 2 12 7 7 .03 .03 .04 .07 .02 .01 .01 .05 .05 .07 .08 .02 .01 .01 .01 .01 .01 .26 .08 .05 4.9 39 12 •102 21 8.4 23 15 7.4 5.5 17 26 347 151 1260 86 41 202 115 12 8 87 .88 45 5.9 •1270 5.7 .95 19 5.6 .24 .12 5.1 1359.39 i TO SEPTEMBER 1997 MEAN DISCHARGE (CFS) SI 6.6 6.0 3.8 3.0 2.5 2.2 2.1 5.3 3.5 2.1 1.7 2.9 2.4 7.1 11 3.6 2.8 11 4.0 3.3 12 17 23 28 12 18 9.2 5.1 4.1 6.6 MEAN CONCEN- TRATION (MO/L) 10 9 13 8 4 4 3 22 29 4 3 14 12 47 55 20 16 65 14 9 63 50 149 105 22 93 57 22 14 51 SEDIMENT DISCHARGE (TONS/DAY) .19 .14 .13 .06 .03 .02 .02 .75 .32 .02 .01 .17 .09 1.2 2.5 .20 .13 2.9 .16 .08 2.8 2.4 12 11 .79 6.4 , 1.6 .30 .15 1.2 221.9 47.76 202 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGOAL, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE AUG 1997 24... TIME 1801 1070 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED* SUSP. FALL DIAH. % FINER THAN .002 MM (70326) SED. SUSP. FALL DIAH. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAH. % FINER THAN .008 MM (70328) 11000 31700 23 28 33 DATE AOG 1997 24... SED. SUSP. FALL DIAM. *» FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAH. % FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 43 57 79 94 98 99 100 203 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE NOV 1996 13... DEC 11... JAN 1997 11... 22. . . JUN 02... JUL 28... AUG 22... 27. .. TIME 1010 0501 1030 1040 1045 1130 1100 1040 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 34 203 18 22 4.0 19 53 24 SEDI- MENT, SUS- PENDED (MG/L) (80154) 124 8700 143 147 309 412 756 626 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 11 4770 6.9 8.7 3.3 21 108 41 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 78 72 98 90 98 100 99 10Q 204 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR LOCATION.--Lat 18°10'24", long 65°58'38", Hydrologic Unit 21010005, on left downstream side of bridge on Highway 181, 0.2 mi (0.3 km) upstream from Rio Grande de Loiza, and 1.5 mi (2.4 km) southwest of San Lorenzo. DRAINAGE AREA.--3.74 mi 2 (9.69 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--January 1984 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 330 ft (100 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV JAN FEB MAY JUN JUL AUG SEP 1 5.4 4.2 2 5.1 4.0 3 4.8 3.6 4 4.8 3.4 5 4.8 3.7 6 4.8 4.6 7 5.0 6.3 8 5.1 8.7 9 6.1 4.2 10 8.6 3.1 11 6.2 4.2 12 5.3 32 13 5.1 15 14 5.1 6.2 15 5.0 5.0 16 4.9 4.1 17 .6 9.7 18 .3 5.2 19 .6 7.9 20 .6 5.8 21 .3 5.0 22 .1 11 23 3.8 5.6 24 3.8 4.3 25 3.5 3.8 26 3.5 3.3 27 4.0 3.0 28 4.6 3.7 29 4.5 3.4 30 3.9 3.9 31 3.8 TOTAL 148.0 187.9 MEAN 4.77 6.26 MAX 8.6 32 MIN 3.5 3.0 AC-FT 294 373 CFSM 1.28 1.67 IN. 1.47 1.87 STATISTICS OF MONTHLY MEAN MEAN 8.68 12.1 MAX 36.2 33.4 (WY) 1986 1988 MIN 2.31 2.72 (WY) 1987 1990 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 3.6 4.0 3.3 3.0 3.3 3.3 3.9 3.3 2.8 2.8 48 7.4 5.7 5.0 4.1 4.1 3.8 3.6 3.5 3.4 3.4 3.4 3.3 3.1 3.5 3.1 3.0 2.8 3.3 14 3.7 168.5 5.44 48 2.8 334 1.45 1.68 DATA 5.11 22.8 1988 1.17 1990 2.7 2.7 2.6 2.6 2.5 2.5 2.5 2.4 2.3 2.3 3.6 2.6 2.3 2.2 2.3 2.2 2.2 2.2 2.4 3.8 13 47 7.7 5.6 5.6 4.5 3.9 4.2 4.3 3.8 3.5 154.0 4.97 47 2.2 305 1.33 1.53 21 12 6.4 4.5 6.4 6.2 5.0 3.9 17 5.1 3.6 3.0 3.5 3.0 2.4 2.5 2.4 2.3 2.5 2.4 3.2 2.9 5.9 2.6 2.6 2.6 2.3 2.2 ___ ___ --- 139.4 4.98 21 2.2 276 1.33 1.39 FOR WATER YEARS 1984 4.93 23.4 1992 1.16 1990 3.32 10.3 1984 1.23 1990 2.2 2.3 2.6 2.5 2.3 2.1 2.1 2.2 2.0 2.0 1.9 2.0 2.1 2.1 2.3 2.4 2.2 2.2 2.2 2.0 2.0 1.9 1.8 1.8 1.8 1.8 1.8 1.9 2.1 2.0 1.8 64.4 2.08 2.6 1.8 128 .56 .64 - 1997 3.02 17.4 1989 1.15 1992 FOR 1996 CALENDAR YEAR 4668 12 1750 9260 3 46 14 3 1 .25 .8 Sep 10 . 93 May 5 .99 May 1 .41 .43 .3 .2 1.8 28 12 3.0 2.2 1.9 1.9 1.6 1.6 1.6 1.5 1.5 1.7 1.5 1.4 1.5 1.5 1.4 1.3 1.3 1.3 1.3 1.2 1.2 1.1 1.1 1.1 .98 1.1 1.0 —— 81.58 2.72 28 .98 162 .73 .81 , BY WATER 2.41 6.60 1985 .66 1995 .95 .90 .89 .91 .85 .79 .78 1.0 1.4 1.7 3.7 1.3 1.1 .94 .94 1.1 2.0 1.1 .90 .90 1.1 1.0 1.0 1.1 1.1 1.1 1.4 2.9 2.0 2.6 1.6 41.05 1.32 3.7 .78 81 .35 .41 YEAR (WY) 6.20 35.8 1985 .86 1995 1.6 2.5 2.5 1.5 1.3 1.3 1.1 .88 .90 .78 .78 .70 .98 .85 .66 .56 .50 .52 .56 .60 .57 .53 .63 1.2 .66 .62 .59 .55 .53 .52 --- 27.47 .92 2.5 .50 54 .24 .27 6.53 17.5 1996 .92 1997 FOR 1997 WATER YEAR 1436.82 3.94 88 .48 .51 962 8.14 .47 2850 1.05 14.29 6.2 2.3 .85 Aug 24 Jul 2 Jun 28 Aug 24 Aug 24 Jul 2 .51 .48 .48 .48 .59 1.2 .74 .61 .62 .60 .53 .48 .58 .55 .58 .93 .99 .94 .91 1.0 9.2 8.0 2.7 3.8 1.6 1.4 1.2 2.3 1.5 1.7 1.2 48.40 1.56 9.2 .48 96 .42 .48 5.68 20.5 1993 1.45 1994 WATER 6. 12. 3. 1750 . . 15000 20. . 4830 1. 24. 10 2. . .99 .85 .94 1.3 1.4 1.5 .90 .87 .88 1.3 2.3 1.5 1.2 1.1 1.0 1.1 1.0 1.2 1.3 1.0 1.4 40 5.5 88 37 7.8 14 12 6.0 4.6 19 258.93 8.35 88 .85 514 2.23 2.58 6.20 14.5 1996 1.51 1994 YEARS 1984 66 4 19 29 41 87 26 78 20 0 92 Sep Sep May Sep Sep May 8.3 5.4 4.5 2.5 1.5 1.4 1.4 38 7.3 2.1 1.5 1.5 1.6 1.4 8.6 1.3 1.1 3.8 1.3 1.0 2.0 1.6 1.4 3.3 1.1 8.0 1.3 .92 e.97 el.l —— 117 . 19 3.91 38 .92 232 1.04 1.17 15.8 76.5 1996 1.88 1990 - 1997 1996 1990 10 1996 12 1990 19 1990 10 1996 10 1996 30 1990 e Estimated RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR—Continued HATER-QUALITY RECORDS PERIOD OF RECORD.— Water years 1984 to 1986 and water years 1989 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1984 to September 1986 and from October 1989 to current year. INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler since 1989. REMARKS.— Sediment samples were collected by local observer on a weekly basis. During high flow sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 7,300 mg/L Oct. 06, 1985; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 33,000 tons (29,900 tonnes) Sep. 10, 1996; Minimum daily mean, <0.01 ton (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 502 mg/L August 24, 1997; Minimum daily mean, 1.0 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 475 tons (431 tonnes) August 24, 1997; Minimum daily mean, <0.01 ton (<0.01 tonne) several days. 205 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 5.4 5.1 4.8 4.8 4.8 4.8 5.0 5.1 6.1 8.6 6.2 5.3 5.1 5.1 5.0 .9 .6 .3 .6 .6 .3 .1 3.8 3.8 3.5 3.5 4.0 4.6 4.5 3.9 3.8 5 8 12 17 16 14 11 5 2 11 2 3 8 14 4 1 1 1 1 1 1 1 1 1 1 2 2 2 1 1 1 .07 .11 .16 .22 .21 .19 .15 .06 .04 .32 .04 .04 .11 .19 .05 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .02 .02 .01 .01 NOVEMBER 4.2 4.0 3.6 3.4 3.7 4.6 6.3 8.7 4.2 3.1 4.2 32 15 6.2 5.0 4.1 9.7 5.2 7.9 5.8 5.0 11 5.6 4.3 3.8 3.3 3.0 3.7 3.4 3.9 1 1 1 1 1 7 21 51 13 6 8 223 124 53 17 13 48 19 32 15 10 45 18 17 15 13 12 10 9 9 .01 .01 .01 .01 .01 .10 .41 2.7 .16 .05 .13 31 5.3 .91 .23 .15 3.5 .27 .75 .24 .14 8.0 .28 .19 .15 .12 .09 .10 .08 .09 ___ DECEMBER 3.6 4.0 3.3 3.0 3.3 3.3 3.9 3.3 2.8 2.8 48 7.4 5.7 5.0 4.1 4.1 3.8 3.6 3.5 3.4 3.4 3.4 3.3 3.1 3.5 3.1 3.0 2.8 3.3 14 3.7 8 7 5 3 2 1 2 4 8 9 426 7 3 3 3 3 5 7 3 1 1 4 10 12 13 9 6 7 8 102 27 .08 .08 .04 .02 .01 .01 .02 .04 .06 .06 308 .14 .05 .04 .03 .04 .05 .06 .03 .01 .01 .03 .09 .10 .12 .08 .05 .05 .07 7.6 .33 148.0 2.15 187.9 55.19 168.5 317.40 206 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 2.7 2.7 2.6 2.6 2.5 2.5 2.5 2.4 2.3 2.3 3.6 2.6 2.3 2.2 2.3 2.2 2.2 2.2 2.4 3.8 13 47 7.7 5.6 5.6 4.5 3.9 4.2 4.3 3.8 3.5 9 6 7 9 10 10 10 8 6 5 4 2 2 9 14 11 8 8 8 13 58 262 22 10 6 3 3 10 24 8 2 .06 .05 .05 .06 .07 .07 .07 .05 .04 .03 .04 .01 .01 .05 .09 .07 .05 .05 .05 .13 5.0 109 .46 .16 .09 .04 .03 .12 .28 .08 .02 FEBRUARY 21 12 6.4 4.5 6.4 6.2 5.0 3.9 17 5.1 3.6 3.0 3.5 3.0 2.4 2.5 2.4 2.3 2.5 2.4 3.2 2.9 5.9 2.6 2.6 2.6 2.3 2.2 ___ ___ ___ 127 49 48 10 19 22 10 10 78 14 11 9 6 5 7 11 15 7 4 8 13 9 26 17 8 4 3 2 ___ ___ ___ 20 2.2 .88 .12 1.2 .47 .13 .10 8.4 .20 .11 .08 .06 .04 .05 .08 .10 .04 .03 .05 .12 .07 .52 .12 .05 .03 .02 .01 ___ ___ ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) MARCH 2.2 2.3 2.6 2.5 2.3 2.1 2.1 2.2 2.0 2.0 1.9 2.0 2.1 2.1 2.3 2.4 2.2 2.2 2.2 2.0 2.0 1.9 1.8 1.8 1.8 1.8 1.8 1.9 2.1 2.0 1.8 6 15 24 7 3 6 7 4 3 3 7 17 19 19 17 15 12 5 2 2 2 2 3 3 6 10 6 2 2 2 2 .03 .09 .16 .05 .02 .03 .04 .02 .01 .01 .04 .09 .10 .10 .10 .09 .07 .03 .01 .01 .01 .01 .01 .02 .03 .05 .03 .01 .01 .01 .01 TOTAL 154.0 116.38 139.4 35.28 64.4 1.30 207 RIO GRANDE DB LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1.8 28 12 3.0 2.2 1.9 1.9 1.6 1.6 1.6 1.5 1.5 1.7 1.5 1.4 1.5 1.5 1.4 1.3 1.3 1.3 1.3 1.2 1.2 1.1 1.1 1.1 .98 1.1 1.0 —— APRIL 4 211 298 117 50 22 11 12 15 21 27 19 13 9 9 8 4 2 3 6 8 7 5 4 3 4 4 5 3 2 .02 68 12 .96 .30 .11 .06 .05 .06 .09 .11 .08 .06 .04 .04 .03 .02 .01 .01 .02 .03 .02 .02 .01 .01 .01 .01 .01 .01 .01 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) .95 .90 .89 .91 .85 .79 .78 1.0 1.4 1.7 3.7 1.3 1.1 .94 .94 1.1 2.0 1.1 .90 .90 1.1 1.0 1.0 1.1 1.1 1.1 1.4 2.9 2.0 2.6 1.6 MAY 5 8 7 5 4 5 6 5 5 5 10 3 3 5 4 3 17 21 13 5 2 2 3 3 4 4 5 6 4 4 5 .01 .02 .02 .01 .01 .01 .01 .01 .02 .02 .16 .01 .01 .01 .01 .01 .11 .06 .03 .01 .01 .01 .01 .01 .01 .01 .03 .05 .02 .03 .02 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 1.6 2.5 2.5 1.5 1.3 1.3 1.1 .88 .90 .78 .78 .70 .98 .85 .66 .56 .50 .52 .56 .60 .57 .53 .63 1.2 .66 .62 .59 .55 .53 .52 .02 .04 .03 .02 .02 .03 .01 .01 <.01 .01 .01 .01 .02 .01 .01 t.Ol .01 .01 .01 t.Ol .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 TOTAL 81.58 82.21 41.05 0.77 27.47 0.28 208 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY DISCHARGE (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 .51 .48 .48 .48 .59 1.2 .74 .61 .62 .60 .53 .48 .58 .55 .58 .93 .99 .94 .91 1.0 9.2 8.0 2.7 3.8 1.6 1.4 1.2 2.3 1.5 1.7 1.2 TOTAL 48.40 YEAR • 1436.82 Estimated MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) JULY 3 4 3 3 3 2 2 2 2 1 1 1 1 1 2 4 5 11 10 7 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .03 .02 .02 47 36 8 14 5 4 3 12 9 4 3 3.5 1.6 .06 .20 .02 .02 .01 .09 .04 .02 .01 5.67 1313.97 MEAN DISCHARGE (CFS) .99 .85 .94 1.3 1.4 1.5 .90 .87 .88 1.3 2.3 1.5 1.2 1.1 1.0 1.1 1.0 1.2 1.3 1.0 1.4 40 5.5 88 37 7.8 14 12 6.0 4.6 19 258.93 CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) AUGUST 3 3 4 4 4 3 3 2 2 3 4 3 3 2 2 2 3 3 2 1 4 201 18 502 93 14 49 57 6 4 88 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .01 .01 .01 .01 .01 .01 .01 .01 59 .03 » .32 475 18 .30 3.0 2.2 .10 .05 6.8 564.99 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 8.3 5.4 4.5 2.5 1.5 1.4 1.4 38 7.3 2.1 1.5 1.5 1.6 1.4 8.6 1.3 1.1 3.8 1.3 1.0 2.0 1.6 1.4 3.3 1.1 8.0 1.3 .92 • .97 •1.1 117.19 6 2 1 1 2 2 2 254 25 7 5 4 4 4 65 9 4 11 5 4 10 9 5 18 5 32 6 5 5 4 121 .15 .03 .01 .01 .01 .01 .01 L .71 .04 .02 .02 .02 .01 i.O .03 .01 .22 .02 .01 .08 .04 .02 .20 .02 4.6 .02 .01 • .01 • .01 132.35 209 RIO QRANDE DE LOXZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE DEC 1996 11... TXME 0529 DIS- CHARGE, XNST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DXAM. \ FINER THAN .002 MM (70326) SED. SUSP. FALL DXAM. * FINER THAN .004 MM (70327) SED. SUSP. FALL DXAM. * FINER THAN .008 MM (70328) 382 7430 7660 25 35 49 DATE DEC 1996 11... SED. SUSP. FALL DIAM. \ FINER THAN .016 MM (70329) SED. SUSP. FALL DXAM. \ FINER THAN .031 MM (70330) SED. SUSP. SIEVE DXAM. \ FINER THAN .062 MM (70331) SED. SUSP. SIEVE DXAM. \ FINER THAN .125 MM (70332) SED. SUSP. SIEVE DXAM. \ FINER THAN .250 MM (70333) SED. SUSP. SIEVE DXAM. * FINER THAN .500 MM (70334) SED. SUSP. SIEVE DXAM. \ FINER THAN 1.00 MM (70335) 63 74 93 98 99 99 100 210 RIO ORANDE DE LOIZA BASIN 50051180 QUEBRADA 8ALVATIERRA NEAR SAN IXXRENZO—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE NOV 1996 13... DEC 11... 11... 30... JAN 1997 22... APR 04... SEP 08... 18... TIME 0950 0500 0614 1030 1010 1000 1626 1011 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 20 34 40 10 58 3.0 117 10 SEDI- MENT, SUS- PENDED (MO/L) (80154) 190 4050 3180 91 282 98 1050 353 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 10 372 343 2.4 44 0.80 332 9.5 SED. SUSP. SIEVE DIAM. \ FINER THAN .062 MM (70331) 99 89 97 98 99 30 98 98 RIO GRANDE DE LOIZA BASIN 50051310 RIO CAYAGUAS AT CERRO GORDO, PR LOCATION.—Lat 18°09'13", long 65°57'20", Hydrologic Unit 21010005, at downstream side of bridge on Highway 912, at Barrio Cerro Gordo, 2.8 mi (4.5 km) south of San Lorenzo. DRAINAGE AREA.—10.2 mi* (26.4 km1 ). PERIOD OF RECORD.--October 1977 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 490 ft (150 m), from topographic map. Prior to Oct. 1, 1983, at site 2,000 ft (610 m) downstream at different datum. REMARKS.—Records poor. Sand removal at a commercial level is practiced at times during the year. This takes place about one hundred feet downstream from the low water control. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 211 OCT NOV JAN FEB MAY JUL AUG SEP 1 e60 61 2 e55 56 3 e67 41 4 64 73 5 61 43 6 52 54 7 56 185 8 48 56 9 55 61 10 103 56 11 71 121 12 44 239 13 41 226 14 40 85 15 52 46 16 41 73 17 37 48 18 36 45 19 37 144 20 36 96 21 36 76 22 35 78 23 35 77 24 34 49 25 34 55 26 41 39 27 39 44 28 36 50 29 40 38 30 38 37 31 39 TOTAL 1463 2352 MEAN 47.2 78.4 MAX 103 239 MIN 34 37 AC-FT 2900 4670 CFSM 4.63 7.69 IN. 5.34 8.58 STATISTICS OF MONTHLY MEAN MEAN 58.9 69.1 MAX 176 196 (WY) 1986 1988 MIN 14.4 19.2 (WY) 1992 1982 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 28 30 30 36 33 39 59 42 43 44 42 26 24 25 24 24 24 21 24 24 23 21 18 22 19 18 14 17 34 75 17 920 29.7 75 14 1820 2.91 3.36 DATA 44.5 163 1988 12.5 1992 16 17 18 17 19 17 17 20 21 20 114 25 21 21 18 20 18 19 20 25 40 102 16 22 17 25 21 22 22 23 18 811 26.2 114 16 1610 2.56 2.96 162 371 124 63 60 91 45 39 84 64 98 84 113 94 72 82 57 37 34 32 47 40 50 23 23 50 19 16 ___ —— 2074 74.1 371 16 4110 7.26 7.56 FOR WATER YEARS 1977 30.0 50.0 1993 14.6 1990 29.3 74.1 1997 11.0 1992 21 25 27 29 26 23 24 25 20 21 21 28 32 34 40 52 29 32 27 24 24 26 36 32 32 28 30 26 23 24 27 868 28.0 52 20 1720 2.75 3.17 - 1997 22.2 45.4 1989 11.3 1992 FOR 1996 CALENDAR YEAR 24058 65.7 5120 13 14 47720 6.44 87.74 102 35 17 Sep 10 May 29 May 25 26 244 182 32 19 16 17 16 617 19 18 21 22 18 16 16 16 15 12 12 11 11 13 18 e!4 12 10 elO e!2 e!3 —— 878 29.3 244 10 1740 2.87 3.20 13 12 11 12 9.3 8.4 10 12 10 31 31 27 14 14 24 20 89 13 11 17 17 12 11 10 11 13 29 35 23 23 19 591.7 19.1 89 8.4 1170 1.87 2.16 22 38 41 16 16 14 14 11 11 11 11 9.9 13 17 11 11 11 9.6 16 14 12 9.6 16 21 13 17 13 13 13 16 461.1 15.4 41 9.6 915 1.51 1.68 15 12 9.7 12 13 24 11 11 15 10 10 12 20 11 10 31 18 13 15 44 399 100 30 22 12 14 11 247 39 178 33 1401.7 45.2 399 9.7 2780 4.43 5.11 14 14 16 23 21 19 18 26 23 128 82 59 28 27 64 80 81 332 96 35 35 489 147 394 151 32 158 166 30 29 79 2896 93.4 489 14 5740 9.16 10.56 33 43 31 28 27 29 29 37 37 25 23 29 28 86 181 34 28 95 33 29 116 359 157 150 28 207 60 26 34 195 —— 2217 73.9 359 23 4400 7.25 8.09 , BY WATER YEAR (WY) 20.4 46.0 1985 10.7 1980 FOR 1997 16933 46 489 8 10 1690 11 33590 4 61 95 27 12 43.3 155 1985 9.68 1990 WATER YEAR .5 .4 Aug 22 . 4 May 6 May 3 Feb 2 .40 Feb 2 .55 .76 45.4 140 1979 10.9 1994 44.0 118 1979 15.4 1994 WATER 43 89 18 5120 7 8 13200 9 31700 4 58 69 24 12 48.8 202 1979 14.5 1991 YEARS 1977 - .8 .7 .6 Sep 10 . 1 Feb 4 .5 Jun 19 Aug 31 .44 Aug 31 .29 .28 68.7 298 1996 16.9 1980 1997 1979 1990 1996 1981 1994 1979 1979 e Estimated 212 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR LOCATION.--Lat 18°11'09", long 65°57'42", Hydrologic Unit 21010005, at upstream side of bridge on Highway 183 by-pass, 0.4 mi (0.6 km) south from Plaza de San Lorenzo, 1.4 mi (2.2 km), southwest from Escuela Rafael Colon Garcia and 2.0 mi (3.2 km) northwest from Escuela Segunda Unidad de Carlos Zayas. DRAINAGE AREA.--25.0 mi 2 (64.8 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--February 1990 to current year. GAGE.—Water-stage recorder. Elevation of gage is 262 ft (80 m), from topographic map. REMARKS.—Records fair except those for estimated discharges, which are poor. Water purification plant located about 0.2 mi (0.3 km) upstream from gage. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES NOV DEC JAN FEB APR MAY JUN ADG SEP 1 e200 141 2 elBO 135 3 e!70 94 4 el60 130 5 elSO 91 6 e!40 104 7 e!30 274 8 6130 175 9 166 147 10 317 116 11 232 240 12 160 735 13 141 583 14 144 239 15 177 174 16 155 151 17 131 162 18 124 133 19 129 223 20 119 168 21 111 172 22 106 161 23 102 159 24 99 127 25 94 113 26 98 104 27 129 100 28 103 104 29 96 99 30 86 107 31 84 —— TOTAL 4363 5461 MEAN 141 182 MAX 317 735 MIN 84 91 AC-FT 8650 10830 CFSM 5.63 7.28 IN. 6.49 8.13 STATISTICS OF MONTHLY MEAN MEAN 122 131 MAX 266 223 (WY) 1991 1992 MIN 77.6 69.2 (WY) 1993 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 102 97 89 89 87 83 106 83 78 77 230 101 86 80 77 81 75 72 69 67 67 65 63 67 76 67 66 63 92 157 90 2702 87.2 230 63 5360 3.49 4.02 DATA 89.3 110 1993 69.7 1994 72 65 64 66 61 59 57 58 57 56 197 94 68 64 61 53 49 49 47 69 113 294 83 70 61 65 52 61 53 47 51 2316 74.7 294 47 4590 2.99 3.45 271 465 152 91 93 132 84 75 122 83 93 84 128 106 84 78 69 63 63 60 81 79 112 70 67 101 67 58 _-_ —— —— 3031 108 465 58 6010 4.33 4.51 FOR WATER YEARS 1990 101 192 1992 50.1 1995 72.4 108 1997 21.0 1992 FOR 1996 CALENDAR YEAR 60107 164 10000 22 26 119200 6 89 269 100 44 Sep 10 May 30 May 25 .57 .44 55 54 58 61 55 54 54 61 59 54 62 56 56 57 75 80 58 59 58 49 48 47 43 53 37 36 39 40 46 43 45 1652 53.3 80 36 3280 2.13 2.46 - 1997, 49.9 76.5 1995 17.4 1992 42 439 252 88 72 62 56 54 51 51 48 48 55 48 44 41 41 38 34 35 34 32 30 30 30 30 31 29 29 28 --- 1902 63.4 439 28 3770 2.54 2.83 BY WATER 36.4 63.4 1997 16.8 1992 27 31 28 29 25 24 26 31 38 62 66 61 47 41 58 53 114 64 45 43 51 43 40 36 42 40 45 90 89 86 61 1536 49.5 114 24 3050 1.98 2.29 YEAR (WY) 63.4 186 1992 25.2 1995 60 89 167 88 66 63 54 47 45 41 42 41 51 70 47 38 36 36 44 49 37 33 37 46 36 38 33 28 27 25 1514 50.5 167 25 3000 2.02 2.25 116 290 1992 42.3 1994 FOR 1997 WATER YEAR 33325 91.3 735 21 24 3420 12.93 66100 3.65 49.59 160 68 34 NOV 12 Jul 3 Jun 28 Aug 24 Aug 24 23 23 21 21 32 47 32 30 32 29 25 23 35 28 22 36 53 36 40 109 337 148 93 75 56 54 46 237 89 155 90 2077 67.0 337 21 4120 2.68 3.09 101 208 1993 42.3 1994 WATER 102 154 67. 10000 6. 7. 56800 35. 74220 4. 55. 173 61 24 68 59 58 59 55 54 49 56 63 109 93 81 67 59 61 70 69 203 87 66 66 588 150 476 205 118 203 159 110 95 135 3791 122 588 49 7520 4.89 5.64 108 196 1996 39.3 1994 YEARS 1990 - 8 Sep 10 3 Apr 29 4 Apr 25 Sep 10 62 Sep 10 10 68 98 98 87 83 79 73 71 89 79 68 65 73 67 92 161 82 73 101 76 66 117 233 153 155 88 148 101 81 81 142 2980 99.3 233 65 5910 3.97 4.43 200 631 1996 59.7 1990 1997 1996 1994 1996 1992 1992 1996 1996 e Estimated RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1990 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: February 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 2,530 mg/L September 10, 1996; Minimum daily mean, 5 mg/L Several days. SEDIMENT LOADS: Maximum daily mean, 80,600 tons (73,100 tonnes) September 10, 1996; Minimum daily mean, 0.20 ton (0.18 tonne) May 05, 1992. EXTREMES FOR CURRENT YEAR 1997-- SEDIMENT CONCENTRATION: Maximum daily mean, 1,650 mg/L August 22, 1997; Minimum daily mean, 8 mg/L April 17-18, 1997. SEDIMENT LOADS: Maximum daily mean, 4,040 tons (3,665 tonnes) November 12, 1996; Minimum daily mean, 0.76 ton (0.69 tonne) April 18, 1997. 213 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) e200 e!80 e!70 e!60 e!50 e!40 e!30 e!30 166 317 232 160 141 144 177 155 131 124 129 119 111 106 102 99 94 98 129 103 96 86 84 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 60 61 64 55 66 84 103 118 150 432 285 159 99 63 139 127 182 134 105 82 70 80 93 104 112 105 185 189 197 206 215 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 4363 e32 e31 e30 e24 e28 e33 e38 e41 70 453 186 69 38 25 71 53 64 45 37 27 21 23 26 28 29 28 64 52 51 48 49 1814 141 135 94 130 91 104 274 175 147 116 240 735 583 239 174 151 162 133 223 168 172 161 159 127 113 104 100 104 99 107 217 107 62 100 77 61 435 179 135 97 323 1560 780 171 76 99 132 64 236 118 163 143 137 58 37 63 96 63 42 56 82 39 16 39 19 17 728 89 61 32 472 4040 1710 114 36 41 64 23 204 54 98 66 61 20 11 18 26 17 11 16 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 102 97 89 89 87 83 106 83 78 77 230 101 86 80 77 81 75 72 69 67 67 65 63 67 76 67 66 63 92 157 90 82 117 156 184 131 87 86 85 78 73 179 54 45 58 78 85 35 15 18 23 19 16 14 17 23 30 38 38 63 570 59 22 31 37 44 31 19 25 19 16 15 207 15 11 13 16 19 7.2 2.9 3.4 4.1 3.5 2.8 2.4 3.2 4.8 5.4 6.7 6.4 20 285 14 5461 8224 2702 911.8 e Estimated 214 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CPS) 72 65 64 66 61 59 57 58 57 56 197 94 68 64 61 53 49 49 47 69 113 294 83 70 61 65 52 61 53 47 51 MEAN CONCEN- TRATION (MG/L) JANUARY 67 77 70 60 44 31 26 42 64 60 1480 1110 431 183 89 108 133 92 59 38 92 483 74 70 65 61 58 57 61 82 111 SEDIMENT DISCHARGE (TONS/DAY) 13 14 12 11 7.3 5.0 4.0 6.7 9.8 8.9 1130 294 80 32 15 15 18 12 7.4 7.2 45 800 17 13 11 11 8.1 9.4 8.7 10 15 MEAN DISCHARGE (CFS) 271 465 152 91 93 132 84 75 122 83 93 84 128 106 84 78 69 63 63 60 81 79 112 70 67 101 67 58 ___ —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 271 465 152 91 93 132 84 75 122 83 93 84 128 106 84 78 69 63 63 60 81 79 112 70 67 101 67 58 514 732 117 54 52 217 176 135 133 79 89 94 76 54 47 42 42 64 88 73 59 51 78 28 22 184 96 82 843 2250 53 13 20 78 39 28 47 18 23 23 26 15 11 8 7 11 15 12 13 11 25 5 4 77 17 13 .9 .7 .3 .0 55 54 58 61 55 54 54 61 59 54 62 56 56 57 75 80 58 59 58 49 48 47 43 53 37 36 39 40 46 43 45 85 90 91 82 78 99 113 84 60 50 82 129 150 163 150 135 125 136 146 141 136 132 128 126 101 81 67 60 53 46 40 13 13 14 14 12 14 17 14 9. 7. 14 20 23 25 30 29 19 22 23 19 17 17 15 20 10 7. 7. 6. 6. 5. 4. 4 4 9 0 5 6 4 9 2316 2650.5 3031 3706.9 1652 469.1 215 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 42 439 252 88 72 62 56 54 51 51 48 48 55 48 44 41 37 34 32 33 32 30 29 28 29 28 30 29 28 28 APRIL 33 741 321 78 41 22 12 10 9 10 10 12 14 15 12 10 8 8 18 42 68 30 13 10 9 15 27 37 21 12 ___ 3.7 3170 364 19 8.0 3.7 1.9 1.5 1.3 1.3 1.3 1.5 2.1 2.0 1.5 1.1 .82 .76 1.6 3.8 5.8 2.5 .98 .73 .71 1.2 2.2 2.8 1.6 .93 26 30 27 29 25 24 26 31 38 62 66 61 47 41 58 53 114 64 45 43 51 43 40 36 42 40 45 90 89 86 61 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 26 30 27 29 25 24 26 31 38 62 66 61 47 41 58 53 114 64 45 43 51 43 40 36 42 40 45 90 89 86 61 16 22 31 43 56 55 54 61 76 129 229 339 251 167 101 62 202 285 271 258 246 234 207 120 65 43 66 139 155 173 164 1.1 1.8 2.3 3.3 3.7 3.5 3.8 5.1 7.8 22 40 56 32 19 16 8.9 73 49 33 30 34 27 22 12 7.5 4.8 9.4 34 38 40 27 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 60 89 167 88 66 63 54 47 45 41 42 41 51 70 47 38 36 36 44 49 37 33 37 46 36 38 33 28 27 25 151 136 139 67 42 33 41 55 69 67 62 33 66 42 48 47 62 87 127 174 104 47 26 39 69 144 232 146 82 51 24 32 66 16 7.5 5.5 6.0 7.0 8.4 7.4 6.9 3.7 11 8.1 6.1 4.7 5.8 7.8 15 23 11 4.2 2.6 4.8 6.7 15 20 11 5.9 3.4 TOTAL 1878 3610.33 1533 667.0 1514 356.5 216 RIO GRANDE DB LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR MEAN DISCHARGE (CFS) 23 23 21 21 32 47 32 30 32 29 25 23 35 28 22 36 53 36 40 109 337 148 93 75 56 54 46 237 89 155 90 2077 33298 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 53 59 66 73 82 92 96 71 51 36 31 59 122 190 97 54 82 63 47 75 779 346 93 54 22 17 15 453 51 345 124 3.3 3.6 3.8 4.1 7.1 12 8.4 5.7 4.4 2.8 2.0 3.6 12 14 5.8 5.5 11 6.0 5.1 31 1100 187 25 11 3.4 2.5 1.8 849 13 190 31 2564.9 34597.53 MEAN DISCHARGE (CFS) 68 59 58 59 55 54 49 56 63 109 93 81 67 59 61 70 69 203 87 66 66 588 150 476 205 118 203 159 110 95 135 3791 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 81 84 91 91 58 34 17 9 31 177 252 66 19 19 21 22 26 268 34 16 31 1650 157 852 282 47 334 565 42 22 86 15 13 14 14 8.5 5.0 2.3 1.4 5.1 59 65 15 3.4 2.9 3.5 4.2 5.1 237 8.1 2.9 5.7 3910 66 3150 223 15 263 269 13 5.6 34 8438.7 i TO SEPTEMBER 1997 MEAN DISCHARGE (CFS) HI 98 98 87 83 79 73 71 89 79 68 65 73 67 92 161 82 73 101 76 66 117 233 153 155 88 148 101 81 81 142 MEAN CONCEN- TRATION (MG/L) 21 13 13 39 98 111 114 141 145 105 130 162 160 154 194 137 120 111 94 65 93 286 145 217 109 131 129 118 107 132 SEDIMENT DISCHARGE (TONS/DAY) 5.7 3.4 3.0 8.7 21 22 22 37 32 19 23 32 29 39 90 30 24 31 19 12 38 235 72 97 26 65 35 26 23 64 2980 1183.8 217 RIO ORANDE DE LOIZA BASIN 50051800 RIO ORANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DIAM. * FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) DATE TIME NOV 1996 12... 0800 1580 7010 29900 13 16 21 JAN 1997 24... 1135 69 1320 246 41 51 61 FEB 26... 0915 206 2590 1440 11 13 17 JUL 21... 1010 776 4140 8680 34 39 48 28... 1000 625 4620 7800 34 40 50 AUO 27... 1000 304 940 771 69 79 81 SED. SED. SED. SED. SED. SED. SED. SUSP. SUSP. SUSP. SUSP. SUSP. SUSP. SUSP. FALL FALL SIEVE SIEVE SIEVE SIEVE SIEVE DIAM. DIAM. DIAM. DIAM. DIAM. DIAM. DIAM. % FINER % FINER % FINER % FINER % FINER % FINER % FINER DATE THAN THAN THAN THAN THAN THAN THAN .016 MM .031 MM .062 MM .125 MM .250 MM .500 MM 1.00 MM (70329) (70330) (70331) (70332) (70333) (70334) (70335) NOV 1996 12... 30 48 72 94 99 100 100 JAN 1997 24... 79 82 99 100 100 100 100 FEB 26... 28 47 78 98 100 100 100 JUL 21... 61 74 94 98 99 100 100 28... 64 79 93 98 100 100 100 AUO 27... 88 90 97 99 99 100 100 218 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE TIME DIS- CHARGE, INST. CUBIC FEET PER SECOND SEDI- MENT, SUS- PENDRD (MO/L) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (00061) (80154) (80155) (70331) NOV 1996 12... DEC 30... JAN 1997 11... MAR 17... MAY 12... JUL 30... AUO 25... 1445 1250 0940 1030 0950 1030 1030 526 134 340 57 83 151 189 900 853 3090 122 379 397 142 1280 308 2840 19 85 162 72 96 94 93 82 99 96 98 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR LOCATION.--Lat 18°09'35", long 66°02'26", Hydrologic Unit 21010005, on left bank at Highway 765, 1.2 mi (1.9 km) south of villa Borinquen, 8.1 mi (13.0 km) upstream from Rio Grande de Loiza. DRAINAGE AREA.--7.14 mi' (18.49 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—January 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 492 ft (150 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 219 DAY OCT NOV JAN FEB MAY JUN JUL AUG SEP 1 28 20 2 27 22 3 28 17 4 26 18 5 25 17 6 24 17 7 24 28 8 25 27 9 29 21 10 58 17 11 29 49 12 23 137 13 22 90 14 22 38 15 23 26 16 21 22 17 19 28 18 19 22 19 20 25 20 19 24 21 18 44 22 17 28 23 17 24 24 16 22 25 15 19 26 21 18 27 31 17 28 23 21 29 18 18 30 17 26 31 17 —— TOTAL 721 902 MEAN 23.3 30.1 MAX 58 137 MIN 15 17 MED 22 22 AC-FT 1430 1790 CFSM 3.26 4.21 IN. 3.76 4.70 STATISTICS OF MONTHLY MEAN MEAN 23.9 23.6 MAX 48.2 37.9 (WY) 1991 1992 MIN 10.3 18 . 6 (WY) 1994 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 25 19 17 16 16 el7 24 17 16 15 115 32 26 23 22 21 19 18 17 17 17 16 16 17 17 16 17 16 26 44 22 716 23.1 115 15 17 1420 3.23 3.73 DATA 17.6 23.1 1991 10.6 1994 21 21 32 28 24 23 22 22 21 21 49 26 23 21 21 20 20 20 21 31 60 94 27 26 23 21 17 26 19 17 17 834 26.9 94 17 22 1650 3.77 4.35 FOR WATER 22.6 47.5 1992 7.85 1990 54 63 29 21 21 20 20 18 28 20 23 22 38 28 23 22 19 18 19 18 27 24 27 19 20 24 18 17 ___ ___ --- 700 25.0 63 17 22 1390 3.50 3.65 YEARS 1990 17.1 25.0 1997 8.93 1990 16 16 17 17 16 16 15 16 16 15 14 14 14 13 17 21 15 15 15 13 13 12 12 12 11 11 11 13 13 12 11 442 14.3 21 11 14 877 2.00 2.30 - 1997 12.0 18.8 1996 7.35 1993 FOR 1996 CALENDAR YEAR 14079. 38. 1940 7. 7. 27930 5. 73. 68 17 9. 8 5 Sep 10 2 May 31 6 May 28 39 36 1 11 69 31 15 13 12 11 11 11 10 11 10 11 10 9.7 9.4 9.2 9.1 8.8 8.6 8.5 8.4 8.1 8.1 8.2 7.8 8.3 8.4 8.3 8.1 —— 373.0 12.4 69 7.8 9.5 740 1.74 1.94 7.9 7.7 7.6 7.7 7.6 7.6 7.7 8.6 7.9 14 9.0 11 8.7 8.0 12 11 33 11 8.5 8.5 9.2 7.8 7.6 7.8 7.9 7.2 11 13 24 17 12 329.5 10.6 33 7.2 8.5 654 1.49 1.72 12 26 54 19 13 12 11 9.9 9.7 9.2 9.9 9.2 12 19 9.7 8.6 8.1 8.8 12 9.8 8.5 7.8 9.0 11 8.5 8.3 7.6 7.3 7.1 7.1 —— 365.1 12.2 54 7.1 9.7 724 1.70 1.90 6.9 6.7 6.5 6.3 8.0 14 8.0 7.6 9.1 7.8 7.2 6.8 7.3 6.6 6.5 17 12 9.0 13 36 90 26 20 14 11 10 9.4 43 15 19 14 473.7 15.3 90 6.3 9.4 940 2.14 2.47 11 10 9.6 10 9.2 8.7 8.3 8.6 9.0 13 11 10 9.6 8.6 8.8 11 9.8 25 13 9.4 9.9 166 25 102 45 24 22 18 16 15 17 673.5 21.7 166 8.3 11 1340 3.04 3.51 15 16 13 13 12 12 12 29 15 12 11 12 11 14 14 11 11 14 11 10 29 35 26 27 16 19 15 13 13 13 474 15.8 35 10 13 940 2.21 2.47 , BY WATER YEAR (WY) 8.77 12.4 1997 6.18 1990 FOR 1997 7003 19 166 6 6 1020 10 2 13890 2 36 28 16 8 14.6 31.9 1993 6.11 1994 WATER YEAR .8 .2 Aug 22 .3 Jul 4 .8 Jun 28 Aug 24 .81 Aug 24 .6 Jul 17 .69 .49 .1 27.0 67.9 1996 9.59 1991 23.8 54.6 1993 8.42 1995 WATER 22 38 12 1940 3 3 15200 22 2 16090 3 42 34 11 5 21.7 41.4 1996 6.98 1994 YEARS 1990 - .2 .1 .1 Sep 10 .3 Aug 17 .8 Aug 11 Sep 10 .60 Sep 10 .6 Jul 17 .11 .26 .9 43.8 123 1996 14.1 1990 1997 1996 1994 1996 1994 1994 1996 1996 1997 e Estimated 220 RZO GRANDE DE LOIZA BASIN 50053025 RIO TORABO ABOVE BORINQUEN, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: January 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 9,230 mg/L September 10, 1996; Minimum daily mean, 1 mg/L Several years. SEDIMENT LOADS: Maximum daily mean, 80,900 tons (73,400 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) Several days. EXTREMES FOR CURRENT YEAR 1997. SEDIMENT CONCENTRATION: Maximum daily mean, 693 mg/L August 22, 1997; Minimum daily mean, 1 mg/L July 13-15, 1997. SEDIMENT LOADS: Maximum daily mean, 732 tons (664 tonnes) August 22, 1997; Minimum daily mean, 0.02 ton (0.02 tonne) July 13-15, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 28 27 28 26 25 24 24 25 29 58 29 23 22 22 23 21 19 19 20 19 18 17 17 16 15 21 31 23 18 17 17 30 30 30 30 30 30 30 30 40 162 179 83 48 30 18 15 14 13 11 8 7 5 4 3 3 19 57 74 70 33 24 2.3 2.2 2.2 2.1 2.0 1.9 2.0 2.0 3.3 39 15 5.2 2.8 1.7 1.1 .84 .73 .65 .58 .43 .32 .24 .18 .14 .12 3.6 9.1 6.0 3.5 1.5 1.2 NOVEMBER 20 22 17 18 17 17 28 27 21 17 49 137 90 38 26 22 28 22 25 24 44 28 24 22 19 18 17 21 18 26 ___ 35 35 25 24 24 23 67 53 34 25 166 427 222 80 68 61 71 33 68 29 125 99 41 36 21 17 15 22 16 38 ___ 2.0 2.2 1.1 1.2 1.1 1.0 9.1 5.8 2.0 1.2 54 225 69 8.7 4.7 3.6 7.5 1.9 4.8 1.9 33 7.7 2.7 2.3 1.1 .83 .71 1.3 .79 2.9 ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 25 19 17 16 16 el7 24 17 16 15 115 32 26 23 22 21 19 18 17 17 17 16 16 17 17 16 17 16 26 44 22 26 11 9 8 8 8 21 9 10 12 346 43 18 16 18 20 22 23 23 15 9 6 4 4 3 4 5 7 40 103 27 2.0 .55 .43 .36 .32 e.35 1.6 .42 .44 .49 264 3.9 1.2 .96 1.0 1.1 1.1 1.1 1.1 .70 .41 .24 .19 .17 .15 .17 .24 .28 4.7 22 1.6 TOTAL 721 113.93 902 461.13 716 313.27 e Estimated 221 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 21 21 32 28 24 23 22 22 21 21 49 26 23 21 21 20 20 20 21 31 60 94 27 26 23 21 17 26 19 17 17 25 30 55 39 29 32 35 36 37 37 99 41 35 28 22 21 23 25 28 51 201 231 42 53 71 47 30 55 28 25 24 1.4 1.7 5.5 3.0 1.9 2.0 2.1 2.1 2.1 2.1 19 2.9 2.1 1.6 1.2 1.2 1.2 1.3 1.7 4.8 65 106 3.1 4.2 4.4 2.7 1.4 5.6 1.5 1.1 1.1 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 54 63 29 21 21 20 20 18 28 20 23 22 38 28 23 22 19 18 19 18 27 24 27 19 20 24 18 17 135 212 154 115 115 108 58 28 36 7 27 23 139 116 94 94 98 100 65 34 26 30 39 13 22 35 20 16 39 53 13 6.6 6.4 5.8 3.0 1.4 3.4 .35 1.8 1.6 15 8.9 5.8 5.6 5.1 5.0 3.3 1.7 2.0 2.0 3.0 .68 1.3 2.6 .96 .73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 16 16 17 17 16 16 15 16 16 15 14 14 14 13 17 21 15 15 15 13 13 12 12 12 11 11 11 13 13 12 11 13 10 9 9 8 8 7 7 7 7 7 8 9 12 25 30 9 13 30 27 24 21 18 13 9 6 6 6 6 6 6 .55 .45 .44 .41 .36 .34 .29 .30 .31 .28 .26 .31 .35 .42 1.2 1.8 .39 .57 1.2 .98 .81 .68 .56 .40 .28 .19 .19 .20 .21 .19 .18 TOTAL 834 257.0 700 199.02 442 15.10 222 i 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CPS) (MG/L) (TONS/DAY) APRIL 11 69 31 15 13 12 11 11 11 10 11 10 11 10 9.7 9.4 9.2 9.1 8.8 8.6 8.5 8.4 8.1 8.1 8.2 7.8 8.3 8.4 8.3 8.1 6 442 103 11 21 26 28 30 31 32 30 13 4 1 1 2 4 7 13 23 26 26 25 25 25 25 24 24 24 25 .17 380 12 .47 .72 .85 .87 .91 .90 .89 .86 .35 .13 .04 .04 .05 .09 .17 .31 .55 .59 .58 .55 .55 .55 .52 .55 .55 .54 .54 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 7.9 7.7 7.6 7.7 7.6 7.6 7.7 8.6 7.9 14 9.0 11 8.7 8.0 12 11 33 11 8.5 8.5 9.2 7.8 7.6 7.8 7.9 7.2 11 13 24 17 12 MAY 25 25 20 14 10 9 9 9 10 9 3 15 8 4 14 14 34 7 6 7 11 9 8 9 9 8 15 29 41 25 15 .54 .53 .40 .29 .22 .19 .18 .22 .22 .35 .06 .49 .18 .09 .48 .43 8.0 .19 .14 .18 .28 .19 .17 .18 .18 .16 .78 1.1 3.8 1.2 .47 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 12 26 54 19 13 12 11 9.9 9.7 9.2 9.9 9.2 12 19 9.7 8.6 8.1 8.8 12 9.8 8.5 7.8 9.0 11 8.5 8.3 7.6 7.3 7.1 7.1 16 47 101 30 18 14 12 11 9 9 10 11 16 31 12 10 9 9 15 12 8 8 10 57 15 5 9 13 18 25 .50 4.9 18 1.6 .65 .46 .35 .28 .24 .23 .27 .26 .58 2.1 .31 .22 .20 .21 .54 .33 .18 .17 .26 1.7 .37 .10 .18 .26 .35 .48 TOTAL 373.0 405.89 329.5 21.89 365.1 36.28 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 223 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CPS) (MO/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 6.9 6.7 6.5 6.3 8.0 14 8.0 7.6 9.1 7.8 7.2 6.8 7.3 6.6 6.5 17 12 9.0 13 36 90 26 20 14 11 10 9.4 43 15 19 14 473.7 7003.8 JULY 33 37 40 38 10 19 10 8 11 7 4 2 1 1 1 27 21 12 24 85 252 41 43 45 38 27 18 99 9 28 13 —— .63 .68 .71 .65 .22 .80 .22 .17 .27 .14 .07 .04 .02 .02 .02 3.1 .79 .29 1.3 18 100 3.5 2.4 1.7 1.1 .76 .46 28 .37 1.6 .49 168.52 3120.42 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) AUGUST MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) 11 10 9.6 10 9.2 8.7 8.3 8.6 9.0 13 11 10 9.6 8.6 8.8 11 9.8 25 13 9.4 9.9 166 25 102 45 24 22 18 16 15 17 5 4 5 5 6 6 7 8 8 15 15 13 12 12 13 13 12 43 17 13 13 693 38 329 95 34 30 13 10 10 14 .15 .12 .12 .14 .14 .15 .16 .17 .20 .64 .44 .35 .31 .28 .30 .37 .32 5.2 .63 .32 .37 732 2.8 309 14 2.3 1.8 .64 .43 .39 .70 SEPTEMBER 673.5 1074.94 15 16 13 13 12 12 12 29 15 12 11 12 11 14 14 11 11 14 11 10 29 35 26 27 16 19 15 13 13 13 474 10 19 5 6 9 13 15 70 12 7 9 11 11 19 21 11 6 16 21 15 58 57 41 67 36 28 22 15 11 8 16 .41 .86 .17 .22 .30 .43 .48 .54 .23 .26 .33 .33 .78 .86 .34 .18 .67 .64 .43 10 5.7 3.1 5.0 1.6 1.5 .91 .52 .38 .28 53.45 224 RIO ORANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN,PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OD SUSPENDED-SEDIMENT DATE AUO 1997 22... TIME 0445 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (HO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SBD. SUSP. FALL DIAM. * FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. \ FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. \ FINER THAN .008 MM (70328) 482 9750 12700 22 26 43 DATE AUO 1997 22... SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) 59 SKD. SUSP. FALL DIAM. * FINER THAN SED. SUSP. SIEVE DIAM. * FINER THAN .031 MM .062 MM (70330) (70331) SED. SED. SUSP. SUSP. SIEVE SIEVE DIAM. DIAM. * FINER * FINNER THAN THAN .125 MM .250 MM (70332) (70333) 77 90 98 100 SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) 100 SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 100 RZO QRANDE DE LOZZA BASIN 50053025 RZO TDRABO ABOVE BORZNQUEN,PR—Continued 225 iTER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 3 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DZS- SEDZ- SED. DATE OCT 1996 12... APR 1997 02... 17... AUG 22... 25... SEP 24... TIME 1505 1745 1347 1546 1300 1500 CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 22 364 9.6 201 38 21 SEDI- MENT, SUS- PENDED (MG/L) (80154) 73 6940 83 77 75 64 MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 4.3 6820 2.2 42 7.7 3.7 SUSP. SIEVE DIAM. \ FINER THAN .062 MM (70331) 97 94 98 99 98 97 226 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR LOCATION.--Lat 18°14'33", long 66°00'34", Hydrologic Unit 21010005, on right bank 250 ft (76 m) upstream from bridge on Highway 189, 1.2 mi (1.9 km) downstream from Rio Turabo, and 1.8 mi (2.9 km) east of Plaza de Caguas. DRAINAGE AREA.—89.8 mi 2 (232.6 km2 ). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—1959 (low-flow measurement only), February to November 1959 (monthly measurements only). December 1959 to current year. GAGE.—Hater-stage recorder. Datum of gage is 143.28 ft (43.672 m) above mean sea level. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e320 317 2 e309 349 3 e320 273 4 e300 293 5 e286 258 6 e278 279 7 e275 520 8 e290 373 9 e340 361 10 e650 325 11 e457 438 12 363 1260 13 326 1050 14 326 345 15 350 249 16 331 210 17 291 263 18 280 215 19 289 336 20 275 285 21 264 296 22 254 509 23 251 327 24 249 248 25 240 222 26 265 191 27 355 180 28 285 208 29 294 194 30 274 234 31 242 —— TOTAL 9629 10608 MEAN 311 354 MAX 650 1260 HIN 240 180 AC-FT 19100 21040 CFSH 3.46 3.94 IN. 3.99 4.39 STATISTICS OF MONTHLY MEAN MEAN 355 315 MAX 1910 1131 (WY) 1971 1988 HIN 44.2 64.9 (WY) 1968 1968 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 222 216 172 165 158 147 193 154 139 135 538 178 123 115 109 116 107 101 99 97 97 96 93 94 130 104 102 103 129 405 212 4849 156 538 93 9620 1.74 2.01 132 106 102 107 92 89 83 84 87 79 290 161 95 87 82 84 77 72 71 114 e250 e400 224 182 168 128 99 105 112 86 86 3934 127 400 71 7800 1.41 1.63 625 782 258 124 117 225 153 133 212 151 146 109 208 152 120 98 87 81 84 82 129 120 171 106 95 140 102 83 ___ ___ 4893 175 782 81 9710 1.95 2.03 DATA FOR HATER YEARS 1960 220 714 1988 33.6 1968 FOR 145 559 1992 45.3 1968 109 291 1984 35.6 1968 78 78 79 97 83 80 75 88 84 74 71 75 85 87 116 136 111 98 113 88 84 79 74 . 73 75 63 67 71 89 82 75 2628 84.8 136 63 5210 .94 1.09 - 1997 91.2 306 1989 23.2 1968 1996 CALENDAR YEAR 121761 333 20000 30 34 241500 3.70 50.44 555 151 57 Sep 10 May 31 May 26 76 823 691 158 124 103 91 88 82 81 77 72 82 78 69 63 62 61 58 55 60 50 43 41 40 40 40 33 30 30 ___ 3401 113 823 30 6750 1.26 1.41 29 30 34 34 30 28 28 40 55 98 137 89 87 74 75 80 171 117 57 44 57 48 43 45 43 39 45 118 114 162 102 2153 69.5 171 28 4270 .77 .89 73 85 288 178 98 79 e66 e56 e54 e52 e54 e53 e65 el08 e54 e42 e37 36 38 69 51 38 49 100 55 45 46 36 32 29 2066 68.9 288 29 4100 .77 .86 29 25 26 23 29 59 75 38 42 49 35 29 42 45 30 37 110 58 63 146 679 471 191 178 120 93 87 444 199 246 146 3844 124 679 23 7620 1.38 1.59 96 76 79 75 66 64 52 56 62 129 157 103 87 64 62 78 82 315 154 88 70 1420 344 1200 613 199 274 292 156 126 195 6834 220 1420 52 13560 2.45 2.83 145 126 114 95 90 86 88 295 179 87 69 85 99 109 239 113 79 113 103 67 126 348 344 236 116 225 177 120 97 205 —— 4375 146 348 67 8680 1.62 1.81 , BY HATER YEAR (WY) 89.7 355 1978 30.6 1995 FOR 1997 59214 162 1420 23 28 7780 12 18 117500 1 24 325 102 43 227 863 1985 33.7 1974 HATER YEAR Aug 22 Jul 4 Jun 29 Aug 24 .78 Aug 24 Jul 5 .81 .53 247 1283 1979 34.1 1975 229 660 1961 21.8 1974 HATER 215 526 82 25300 11 11 83000 32 17 156000 2 32 360 106 39 266 949 1979 51.4 1994 YEARS 1960 - .3 Sep 6 Apr 8 Apr 8 Sep 10 .32 Sep 10 Aug 18 .40 .58 317 1438 1960 37.4 1967 1997 1979 1967 1960 1968 1968 1996 1996 1994 e Estimated RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1959 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1983 to current year. INSTRUMENTATION.— USD-49 sediment sampler since October 1983. Automatic sediment sampler since 1984. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean,14,500 rag/L Nov 27, 1987; Minimum daily mean, 8 mg/L January 23, 1992. SEDIMENT LOADS: Maximum daily mean, 396,000 tons (359,000 tonnes) September 10, 1996; Minimum daily mean, 0.65 tons (0.59 tonnes) May 25,1995. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,610 mg/L April 2, 1997 ; minimum daily mean, 11 mg/L April 27, 1997. SEDIMENT LOADS: Maximum daily mean, 14,600 tons (13,300 tonnes) April 2, 1997; minimum daily 1.0 ton (0.90 tonnes) May 1-2,1997. 227 WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 20... MAR 1997 04... MAY 20... SEP 04... NOV 20 MAR 04 MAY 20 SEP 04 NOV 20 MAR 04 MAY 20 SEP 04 K - DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CREM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1015 378 248 6.9 25.5 80 6.2 74 <10 41000 25000 0830 103 258 6.9 24.5 18 7.0 83 <10 K9100 750 0930 45 272 6.8 28.5 20 6.5 82 <10 560 K110 0950 95 239 6.9 29.5 6.5 6.4 84 <10 3900 240 ALKA- HARD- NESS TOTAL (MG/L DATE AS CACO3) (00900) 1996 61 1997 ... 78 69 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 0.10 1997 ... 0.15 0.11 non- ideal count CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 16 -- 20 18 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 27 -- 32 32 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.1 -- 6.6 5.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 130 -- 171 156 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 16 -- 21 18 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 133 -- 20.7 40.1 SODIUM AD- SORP- TION RATIO (00931) 0.9 -- 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 124 25 31 15 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.3 -- 2.3 2.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.590 0.410 0.470 0.360 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 67 84 86 85 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.050 0.020 0.040 0.040 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.640 0.430 0.520 0.400 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 9.2 -- 16 10 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.130 0.070 0.010 0.140 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 14 -- 21 18 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.57 0.24 0.33 0.28 228 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR—Continued DATE NOV 1996 20... MAR 1997 04... MAY 20... SEP 04... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.70 0.32 0.43 0.42 NITRO- GEN, TOTAL (HG/L AS N) (00600) 1.3 0.75 0.94 0.82 NITRO- GEN, TOTAL (HG/L AS N03) (71887) 5.9 3.3 4.2 3.6 PHOS- PHORUS TOTAL (HG/L AS P) (00665) 0.160 0.090 0.080 0.050 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- 100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 _- 30 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — DATE NOV 1996 20... MAR 1997 04... MAY 20... SEP 04... IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L AS FE) AS PB) (01045) (01051) 4200 870 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) 310 230 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) <0.10 <0.10 SILVER, SELE- TOTAL NIUM, RECOV- TOTAL ERABLE (UG/L (UG/L AS SE) AS AG) (01147) (01077) <1 <1 <1 <1 ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL (UG/L (MG/L AS ZN) AS CN) (01092) (00720) 20 <0.010 10 <0.010 METHY- LENE BLUE ACTIVE PHENOLS SUB- TOTAL STANCE (UG/L) (MG/L) (32730) (38260) <1 <1 <0.01 <0.01 non-ideal count RIO GRANDE DE LOIZA BASIN 50055000 RIO ORANDE DE LOIZA AT CAGDAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 229 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 •320 •309 •320 •300 •286 •278 •275 •290 e340 e650 e457 363 326 326 350 331 291 280 289 275 264 254 251 249 240 265 355 285 294 274 242 175 228 152 189 263 253 248 242 189 189 520 397 359 362 388 264 376 356 173 75 105 166 216 262 268 293 389 196 331 121 70 elSl •194 •129 •158 •208 •193 e!85 e!85 e!60 e261 •688 390 316 319 371 237 295 270 134 56 75 114 147 176 174 214 378 154 265 92 46 NOVEMBER 1 317 349 273 293 258 279 520 373 361 325 438 1260 1050 345 249 210 263 215 336 285 296 509 327 248 222 191 180 208 194 234 —— 312 323 117 230 159 237 488 409 408 362 420 1150 681 304 136 126 186 250 313 287 269 499 327 180 184 205 211 101 40 179 ___ 286 310 87 197 111 183 912 426 408 327 693 5160 2390 281 93 73 193 147 334 225 281 936 294 121 110 106 103 55 21 129 —— 222 216 172 165 158 147 193 154 139 135 538 178 123 115 109 116 107 101 99 97 97 96 93 94 130 104 102 103 129 405 212 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) 222 216 172 165 158 147 193 154 139 135 538 178 123 115 109 116 107 101 99 97 97 96 93 94 130 104 102 103 129 405 212 99 218 98 44 41 48 141 52 46 53 513 254 97 42 19 18 22 23 24 23 21 20 19 20 130 118 110 118 141 389 237 62 129 46 20 18 19 80 22 17 19 1120 130 33 13 5.6 5.7 6.4 6.4 6.3 5.9 5.6 5.3 4.8 5.0 47 33 30 33 55 445 139 TOTAL 9629 6735 10608 14992 4849 2567.0 • Estimated 230 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGDAS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 132 106 102 107 92 89 83 84 87 79 290 161 95 87 82 84 77 72 71 114 e250 6400 224 182 168 128 99 105 112 86 86 111 35 28 30 29 29 29 32 36 36 290 169 61 62 73 90 79 70 63 70 113 357 261 279 194 115 65 97 132 102 96 41 9. 7. 8. 7. 6. 6. 7. 8. 7. 331 81 16 15 16 20 16 14 12 22 e43 e399 161 138 91 40 17 31 41 24 22 9 8 5 3 8 4 3 5 7 625 782 258 124 117 225 153 133 212 151 146 109 208 152 120 98 87 81 84 82 129 120 171 106 95 140 102 83 592 730 261 139 138 250 186 134 204 173 184 114 221 166 139 106 65 56 52 89 173 142 216 121 148 220 271 92 2120 3710 211 47 44 167 80 50 151 73 77 35 127 68 46 28 15 12 12 20 66 47 113 35 39 101 77 21 MEAN DISCHARGE (CPS) 78 78 79 97 83 80 75 88 84 74 71 75 85 87 116 136 111 98 113 88 84 79 74 73 75 63 67 71 89 82 75 MEAN CONCEN- TRATION (MG/L) MARCH 91 90 90 169 146 136 101 96 83 52 63 82 88 88 123 137 116 64 122 109 114 115 111 91 72 64 74 87 101 43 35 SEDIMENT DISCHARGE (TONS/DAY) 19 19 19 44 33 29 21 23 19 10 12 17 20 21 40 53 36 17 38 26 26 24 22 18 15 11 14 17 24 9.5 7.2 3934 1661.2 4893 7592 2628 703.7 e Estimated 231 MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MO/L) (TONS/DAY) MAY JUKE TOTAL RIO ORAKDE DE LOIZA BASIN 50055000 RIO ORANOE DE LOIZA AT CAGUAS, W--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN DISCHARGE (CFS) 73 85 288 178 98 79 •66 •56 •54 •52 •54 •S3 •65 •108 •54 •42 •37 36 38 69 51 38 49 100 55 45 46 36 32 29 2066 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 76 823 691 158 124 103 91 88 82 81 77 72 82 78 69 63 62 61 58 55 60 50 43 41 40 40 40 33 30 30 APRIL 32 1610 512 191 93 37 26 20 20 21 19 16 15 17 22 19 16 16 17 18 16 13 14 15 14 12 11 15 22 18 6.7 14600 1440 83 32 11 6.3 4.8 4.4 4.5 3.9 3.2 3.2 3.6 4.0 3.3 2.6 2.6 2.7 2.8 2.5 1.7 1.6 1.7 1.5 1.3 1.1 1.3 1.8 1.5 SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) 3401 16240.6 29 30 34 34 30 28 28 40 55 98 137 89 87 74 75 80 171 117 57 44 57 48 43 45 43 39 45 118 114 162 102 2153 13 13 38 37 37 39 30 34 58 113 133 97 76 54 74 89 213 189 63 40 65 89 70 48 40 43 58 142 157 173 113 1.0 1.0 3.5 3.5 3.0 2.9 2.2 3.8 10 33 50 24 18 11 15 19 137 65 9.9 4.7 10 11 8.1 5.8 4.6 4.6 7.3 48 49 76 31 672.9 78 102 353 194 81 76 94 112 104 90 66 49 63 96 146 193 146 99 48 59 41 38 50 95 51 47 51 39 35 33 16 24 283 99 22 16 •16 •18 •15 •13 •9.4 •7.0 •10 •22 •30 •25 •16 9.6 5.0 11 5.6 3.9 8.2 26 7.7 5.8 6.3 3.7 3.1 2.6 739.9 • Estimated 232 RIO GRANDE KB LOZZA BASIN 50055000 RIO ORANDB KB LOZZA AT CAOOAS, PR—Continued SEDIMENT DZSCBAROB, SUSPENDED (TONS/DAY), KATBR YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY DISCHARGE (CFS) CQMCEN** TRATZON DZSCHAROE (MO/L) (TOMS/DAY) JULY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL 29 25 26 23 29 59 75 38 42 49 35 29 42 45 30 37 110 58 63 146 679 471 191 178 120 93 87 444 199 246 146 3844 35 28 28 24 33 63 73 40 34 S3 34 26 30 75 100 60 124 68 70 159 772 475 165 62 40 30 29 402 230 217 143 2.7 1.9 2.0 1.5 2.7 11 15 4.1 3.9 7.0 3.3 2.0 3.6 9.0 8.0 6.0 39 11 12 67 1910 729 83 30 13 7.6 6.8 1010 131 174 57 4364.1 DZSCHARQE (CPS) 96 76 79 75 66 64 52 56 62 129 157 103 87 64 62 78 82 315 154 88 70 1420 344 1200 613 199 274 292 156 126 195 6834 CONCEN- SEDIMENT TRATZON DISCHARGE (MO/L) (TONS/DAY) DISCHARGE (CPS) CONCBN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) AUGUST SEPTEMBER 46 31 51 29 22 23 19 16 15 97 79 43 36 28 31 86 38 343 121 44 22 1080 292 569 332 45 215 441 175 144 208 12 6.4 11 5.8 3.9 3.9 2.7 2.4 2.5 49 36 12 8.5 4.8 5.6 19 9.0 411 55 11 4.1 6710 330 7320 840 25 230 375 74 49 120 16748.6 145 126 114 95 90 86 88 295 179 87 69 85 99 109 239 113 79 113 103 67 126 348 344 236 116 225 177 120 97 205 4375 107 108 25 15 15 37 76 233 195 S3 34 59 110 120 364 117 44 95 128 76 137 303 350 196 107 250 201 135 55 192 43 38 7.7 3.9 3.7 10 19 486 113 13 6.3 16 30 39 279 38 9.4 40 37 14 57 348 406 140 34 209 107 47 14 153 2761.0 YEAR 59214 75778.0 233 RIO ORMJDE DB LOIZA BASIN 50055000 RIO QRANDE DB LOIZA AT CAOUAS, PR—Continued WATER QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE APR 1997 02... 02... JUL 21... AUO 22... 22... TIME 2015 2115 1445 1050 0900 1700 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 4270 4510 SEDI- MENT, SUS- PENDED (MO/L) (80154) 17000 6750 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 196000 82200 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 23 28 SED. SUSP. FALL DIAM. \ FINER THAN .004 MM (70327) 32 33 SED. SUSP. FALL DIAM. \ FINER THAN .008 MM (70328) 46 49 2210 3130 2680 7600 2450 14600 2830 23900 60 45 51 72 54 58 80 62 64 DATE APR 1997 02... 02... JUL 21... AUO 22... 22... SED. SUSP. FALL DIAM. \ FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. \ FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. \ FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP SIEVE DIA \ FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. \ FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. \ FINER THAN 1.00 MM (70335) 65 64 88 80 77 82 81 90 87 86 95 94 99 98 99 99 98 100 100 100 100 99 100 100 100 100 100 100 100 100 100 100 100 100 100 234 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS—Continued HATER QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 06... DEC 12... 30... APR 1997 03... 03... 03... JUN 03... JUL 22... 28... AUG 25... 28... SEP 26... TIME 1410 0653 1205 0030 0330 1630 1515 0215 1630 0315 1515 16CO DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) £27 8 193 443 2850 1240 75 258 1100 902 1030 225 285 SEDI- MENT, SUS- PENDED (MG/L) (80154) 248 300 267 1560 789 325 431 899 882 736 593 177 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) E186 156 319 12000 2640 66 300 2670 2150 2050 360 136 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 96 90 90 98 100 98 100 100 100 100 100 99 235 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AQUAS BUENAS, PR LOCATION.--Lat 18°14'48", long 66°05'37», Hydrologic Unit 21010005, on right bank 450 ft (137 m) upstream from bridge on Highway 777, 1.0 mi (1.6 km) southeast from Aguas Buenas, 3.9 mi (6.3 km) northwest from Caguas, and 2.1 mi (3.4 km) southwest from Las Carolinas. DRAINAGE AREA.--5.30 mi 1 (13.72 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 394 ft (120 m), from topographic map. REMARKS.—Records fair. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN PEB MAR APR MAY JUN JUL AUG SEP 1 9.6 6.8 2 10 7.0 3 8.2 5.6 4 8.0 6.0 5 7.6 6.5 6 7.9 5.9 7 7.4 8.9 8 7.1 5.1 9 7.1 4.6 10 8.1 3.5 11 7.4 5.2 12 6.8 9.0 13 6.9 9.1 14 6.8 5.0 15 6.2 4.0 16 5.9 3.6 17 5.6 5.0 18 5.6 5.0 19 5.4 4.7 20 5.2 5.2 21 5.3 14 22 5.2 9.1 23 5.2 7.8 24 5.2 6.7 25 5.0 7.3 26 8.4 5.4 27 6.7 8.6 28 16 12 29 10 7.4 30 7.8 19 31 6.2 TOTAL 223.8 213.0 MEAN 7.22 7.10 MAX 16 19 MIN 5.0 3.5 AC-FT 444 422 CFSM 1.36 1.34 IN. 1.57 1.50 14 12 8.3 8.2 6.5 7.7 8.3 6.2 4.2 3.5 8.0 4.9 4.2 3.9 4.1 4.8 3.9 3.6 3.3 3.1 3.4 3.3 3.1 3.1 4.3 3.8 3.4 2.8 6.6 6.1 4.4 167.0 5.39 14 2.8 331 1.02 1.17 3.3 3.5 2.9 2.7 2.5 2.6 2.6 2.4 2.4 2.7 3.6 2.4 2.4 2.3 2.5 2.6 2.4 3.3 4.8 3.6 46 64 16 34 25 10 6.8 9.8 6.7 6.1 6.2 288.1 9.29 64 2.3 571 1.75 2.02 7.4 6.8 4.3 4.8 5.4 5.0 5.1 3.9 5.5 3.9 3.5 4.0 7.6 4.3 3.5 2.9 2.7 2.8 3.3 3.8 13 6.9 5.6 5.1 4.7 5.4 4.9 4.4 ___ ___ --- 140.5 5.02 13 2.7 279 .95 .99 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1990 MEAN 7.93 7.21 MAX 20.9 12.3 (WY) 1991 1993 MIN 3.17 2.66 (WY) 1996 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 6.43 13.4 1993 2.34 1995 FOR 8.54 16.7 1992 2.48 1995 4.81 8.00 1991 2.96 1995 4.1 4.3 5.0 3.8 5.9 4.1 3.4 5.0 3.4 3.0 2.6 2.7 2.4 1.9 2.0 2.0 1.8 1.8 1.8 1.8 1.9 1.9 1.8 1.8 1.8 1.8 3.4 6.8 4.3 2.7 2.2 93.2 3.01 6.8 1.8 185 .57 .65 - 1997 4.56 8.87 1990 2.09 1996 1996 CALENDAR YEAR 3361.5 9.18 1260 1.2 1.2 6670 1.73 23.59 11 3.3 1.6 Sep 10 May 1 Apr 30 2.1 2.5 3.2 2.7 2.5 2.3 2.3 2.3 2.1 1.9 1.9 1.9 1.7 1.7 1.7 1.8 1.8 1.7 1.7 1.8 1.9 2.3 2.4 2.1 1.8 1.6 2.2 2.3 2.2 2.1 --- 62.5 2.08 3.2 1.6 124 .39 .44 , BY WATER 4.58 13.1 1993 1.84 1995 2.0 1.9 2.3 2.1 2.0 2.0 2.0 2.0 2.0 2.5 2.4 2.0 2.3 2.0 1.8 1.6 2.0 1.7 1.7 1.6 1.9 1.4 1.6 2.2 1.9 1.4 1.3 1.8 3.4 2.8 2.3 61.9 2.00 3.4 1.3 123 .38 .43 YEAR (WY) 5.35 18.0 1993 2.00 1997 2.0 2.1 2.9 2.2 1.9 1.9 1.8 2.0 2.2 1.8 1.8 1.8 2.6 1.6 1.6 1.6 1.8 1.9 1.7 1.2 1.2 1.1 1.3 2.7 2.1 1.8 2.0 1.7 1.8 1.8 --- 55.3 1.84 2.9 1.1 110 .35 .39 4.23 8.05 1993 1.84 1997 FOR 1997 WATER YEAR 1574.0 4.31 64 1.0 1.3 217 11.45 .82 3120 .81 11.05 7.8 2.7 1.6 jan 22 Aug 1 Sep 5 Jan 21 Jan 21 Jul 29 2.0 2.0 1.9 1.8 1.9 2.2 5.1 3.2 1.9 1.8 2.0 2.5 1.8 1.5 1.3 1.5 1.5 6.5 7.7 3.3 5.2 3.7 1.7 2.2 1.5 1.4 1.8 1.9 1.3 2.1 1.3 77.5 2.50 7.7 1.3 154 .47 .54 5.92 18.6 1993 1.86 1994 1.0 1.5 25 9.4 4.2 2.8 2.5 1.9 1.6 2.4 1.9 1.7 1.8 1.8 1.4 1.4 2.3 2.6 1.5 1.3 1.4 8.3 2.8 14 9.1 2.9 2.2 1.9 1.7 1.8 2.2 118.3 3.82 25 1.0 235 .72 .83 6.09 11.2 1993 1.85 1994 WATER YEARS 1990 - 6.68 11.1 4.31 1260 1.0 1.2 4490 21.22 .82 4840 1.26 17.13 9.2 4.1 1.9 Sep 10 Aug 1 Apr 30 Sep 10 Sep 10 Jul 29 1.8 1.8 1.7 1.6 1.5 1.4 1.3 1.1 1.3 1.2 1.1 7.8 3.5 2.2 1.8 1.5 1.3 2.2 1.5 2.3 3.9 2.6 2.8 1.8 1.5 6.3 2.4 6.5 2.9 2.3 72.9 2.43 7.8 1.1 145 .46 .51 12.9 52.9 1996 2.43 1997 1997 1993 1997 1996 1997 1996 1996 1996 1997 236 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: February 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 5,300 mg/L September 10, 1996; Minimum daily mean, 1 mg/L July 16-17, 1997. SEDIMENT LOADS: Maximum daily mean, 24,500 tons (22,200 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) July 16-17, 1997. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,580 mg/L August 03, 1997; Minimum daily mean, 1 mg/L July 16-17, 1997. SEDIMENT LOADS: Maximum daily mean, 443 tons (401 tonnes) August 3, 1997; Minimum daily mean, <0.01 ton «.01 tonne) July 16-17, 1997 . SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.6 10 8.2 8.0 7.6 7.9 7.4 7.1 7.1 8.1 7.4 6.8 6.9 6.8 6.2 5.9 5.6 5.6 5.4 5.2 5.3 5.2 5.2 5.2 5.0 8.4 6.7 16 10 7.8 6.2 53 40 30 22 17 12 9 7 5 5 5 5 7 9 11 7 4 2 2 2 2 3 3 4 6 78 59 315 49 72 50 1.4 1.0 .68 .48 .34 .27 .19 .13 .10 .11 .10 .09 .13 .16 .18 .11 .06 .03 .03 .03 .03 .04 .05 .06 .09 2.6 1.1 40 1.9 1.6 .83 NOVEMBER 6.8 7.0 5.6 6.0 6.5 5.9 8.9 5.1 4.6 3.5 5.2 9.0 9.1 5.0 4.0 3.6 5.0 5.0 4.7 5.2 14 9.1 7.8 6.7 7.3 5.4 8.6 12 7.4 19 37 34 32 30 28 25 51 47 45 180 191 142 107 85 70 55 100 164 131 80 587 65 98 85 73 53 94 100 53 259 .69 .64 .48 .49 .49 .41 1.5 .66 .57 1.9 2.6 3.4 2.7 1.2 .75 .53 1.6 2.2 1.7 1.1 87 1.8 2.0 1.5 1.4 .76 4.5 3.5 1.0 18 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 14 12 8.3 8.2 6.5 7.7 8.3 6.2 4.2 3.5 8.0 4.9 4.2 3.9 4.1 4.8 3.9 3.6 3.3 3.1 3.4 3.3 3.1 3.1 4.3 3.8 3.4 2.8 6.6 6.1 4.4 76 42 32 24 16 10 7 12 24 48 74 27 7 6 7 8 13 20 34 82 222 500 224 59 24 17 34 27 63 53 36 2.8 1.3 .72 .54 .28 .21 .16 .19 .27 .47 1.7 .38 .08 .06 .08 .10 .13 .19 .29 .69 2.1 4.5 1.9 .49 .31 .20 .31 .20 1.7 .93 .51 TOTAL 223.8 53.92 213.0 147.07 167.0 23.79 237 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 3.3 3.5 2.9 2.7 2.5 2.6 2.6 2.4 2.4 2.7 3.6 2.4 2.4 2.3 2.5 2.6 2.4 3.3 4.8 3.6 46 64 16 34 25 10 6.8 9.8 6.7 6.1 6.2 31 26 12 7 7 9 12 15 19 29 188 166 147 130 115 111 111 120 47 33 736 703 157 370 178 94 73 114 44 25 17 .28 .25 .10 .05 .05 .07 .08 .10 .12 .28 1.8 1.1 .94 .80 .79 .78 .70 1.9 .94 .37 240 165 7.9 56 15 2.6 1.3 5.2 .82 .42 .28 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 7.4 6.8 4.3 4.8 5.4 5.0 5.1 3.9 5.5 3.9 3.5 4.0 7.6 4.3 3.5 2.9 2.7 2.8 3.3 3.8 13 6.9 5.6 5.1 4.7 5.4 4.9 4.4 89 148 132 86 52 31 16 9 5 6 9 14 58 15 10 14 22 33 42 52 133 52 18 7 12 32 75 45 2.1 2.7 1.5 1.1 .74 .43 .21 .09 .07 .06 .09 .16 1.5 .17 .10 .11 .16 .25 .37 .54 5.6 1.0 .28 .09 .15 .48 .99 .54 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 4.1 4.3 5.0 3.8 5.9 4.1 3.4 5.0 3.4 3.0 2.6 2.7 2.4 1.9 2.0 2.0 1.8 1.8 1.8 1.8 1.9 1.9 1.8 1.8 1.8 1.8 3.4 6.8 4.3 2.7 2.2 17 7 7 7 8 12 20 28 18 10 6 5 5 5 5 5 5 4 4 4 7 13 21 15 8 4 22 73 46 14 9 .19 .08 .09 .07 .13 .13 .18 .39 .17 .08 .04 .04 .03 .03 .03 .03 .02 .02 .02 .02 .04 .07 .10 .07 .04 .02 .78 2.8 .70 .11 .05 TOTAL 288.1 506.02 140.5 21.58 93.2 6.57 238 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AQUAS BDENAS , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 2.1 2.5 3.2 2.7 2.5 2.3 2.3 2.3 2.1 1.9 1.9 1.9 1.7 1.7 1.7 1.8 1.8 1.7 1.7 1.8 1.9 2.3 2.4 2.1 1.8 1.6 2.2 2.3 2.2 2.1 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 7 15 28 9 4 4 4 4 5 6 8 9 9 10 10 11 9 8 8 7 5 4 3 5 7 11 11 11 10 10 .04 .15 .25 .06 .03 .03 .03 .03 .03 .03 .04 .04 .04 .05 .05 .05 .05 .04 .04 .03 .03 .03 .02 .03 .04 .05 .06 .07 .06 .06 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) MAY 2.0 1.9 2.3 2.1 2.0 2.0 2.0 2.0 2.0 2.5 2.4 2.0 2.3 2.0 1.8 1.6 2.0 1.7 1.7 1.6 1.9 1.4 1.6 2.2 1.9 1.4 1.3 1.8 3.4 2.8 2.3 10 10 9 9 9 9 9 9 8 8 8 11 16 22 16 9 6 8 12 18 23 27 31 19 9 5 5 7 29 25 11 .05 .05 .06 .05 .05 .05 .05 .05 .04 .05 .05 .06 .10 .12 .08 .04 .03 .04 .05 .08 .11 .10 .14 .12 .05 .02 .02 .03 .57 .21 .07 2.0 2.1 2.9 2.2 1.9 1.9 1.8 2.0 2.2 1.8 1.8 1.8 2.0 1.6 1.6 1.6 1.8 1.9 1.7 1.2 1.2 1.1 1.3 2.7 2.1 1.8 2.0 1.7 1.8 1.8 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 3 3 8 9 7 5 7 9 20 23 16 11 12 16 21 .05 .04 .05 .03 .03 .03 .02 .02 .03 .02 .02 .02 .02 .02 .01 .01 .01 .08 .04 .02 .02 .02 .03 .24 .13 .08 .06 .06 .08 .11 TOTAL 62.5 1.56 61.9 2.59 55.3 1.40 239 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGtflTAS NEAR AQUAS BDENAS , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 2.0 2.0 1.9 1.8 1.9 2.2 5.1 3.2 1.9 1.8 2.0 2.5 1.8 1.5 1.3 1.5 1.5 6.5 7.7 3.3 5.2 3.7 1.7 2.2 1.5 1.4 1.8 1.9 1.3 2.1 1.3 77.5 1574.0 JULY 27 20 12 8 6 5 37 29 17 12 9 6 4 3 2 1 1 75 634 35 47 26 22 29 35 27 19 13 9 6 4 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) AUGUST .14 .10 .06 .04 .03 .03 1.1 .28 .09 .06 .05 .04 .02 .01 .01 <.01 <.01 4.3 52 .34 .79 .28 .10 .16 .14 .10 .09 .06 .03 .03 .01 60.49 1459.97 1.0 1.5 25 9.4 4.2 2.8 2.5 1.9 1.6 2.4 1.9 1.7 1.8 1.8 1.4 1.4 2.3 2.6 1.5 1.3 1.4 8.3 2.8 14 9.1 2.9 2.2 1.9 1.7 1.8 2.2 118.3 4 4 1580 324 35 16 8 7 10 19 19 15 14 14 13 13 19 30 15 14 16 176 33 620 448 84 58 40 28 19 14 —— .01 .02 443 10 .40 .12 .05 .04 .04 .19 .10 .07 .07 .07 .05 .05 .22 .24 .06 .05 .06 8.0 .25 79 14 .67 .34 .21 .13 .09 .08 557.68 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 1.8 1.8 1.7 1.6 1.5 1.4 1.3 1.1 1.3 1.2 1.1 7.8 3.5 2.2 1.8 1.5 1.3 2.2 1.5 2.3 3.9 2.6 2.8 1.8 1.5 6.3 2.4 6.5 2.9 2.3 12 11 10 11 11 12 10 9 8 9 10 494 48 91 71 49 35 31 30 29 29 29 29 26 18 76 67 241 144 95 .06 .05 .05 .05 .04 .04 .04 .03 .03 .03 .03 49 .61 .55 .34 .20 .12 .18 .12 .18 .31 .20 .22 .13 .07 2.4 .44 20 1.2 .58 72.9 77.30 240 RIO ORANDE DC LOIZA BASIN 50055100 RIO CAO0ITAS NEAR AGRJAS BUENAS, PR—Continued HATER QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DIS- CHARGE, INST. CUBIC SEDI- DATE NOV 1996 21... AUO 1997 03... TIME 1700 1745 PER SECOND SUS- PENDED (MO/L) SEDI- MENT, DIS- CHARGE, SUS- SED. SUSP. PALL DIAM. SED. SED. SUSP. SUSP. PALL PALL DIAM. DIAM. (T/DAY) % FINER % FINER % FINER THAN THAN THAN .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) 92 167 7660 1900 19000 8570 29 28 37 33 52 46 DATE NOV 1996 21... AUO 1997 03... SED. SUSP. PALL DIAM. % FINER THAN .016 MM (70329) 67 60 SED. SUSP. PALL DIAM. % FINER THAN .031 MM (70330) 77 73 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 95 91 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 97 97 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 jog. M MM M A<OM O M » W W O M AO M M MO M M M»OMWO MO O *W M O M M Ul O M M W M W ill »M M •J O M A MMMMWM IOOWOOA « U> M0> M O 242 RIO GRANDE OB LOXZA BASIN 50055170 RIO CAGUITAS NEAR CAOOAS, PR LOCATION.--Lat 18°13'59", long 66«02'53", Bydrologic Unit 21010005, on l«£t bank, 0.9 mi (1.4 km) southwest from Plaza da Caguas, 0.6 mi (1.0 km) northeast from Escuela Bunker, and 1.2 mi (1.9 km) northwest from Escuela Antonio S. Pedreira. DRAINAGE AREA.—8.27 mi* (21.42 k»»). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—May 1992 to September 30, 1997. (discontinued) GAGE.—Water-stage recorder and erect-stage gage. Elevation of gage is 216 ft (66 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV JAN MAR APR MAY JUN JUL AUG SEP 1 e!2 ell 2 e!3 ell 3 ell e8.6 4 elO e9.4 5 e9.8 elO 6 elO e9.0 7 e9.7 e!4 8 e9.2 e7.6 9 e9.2 e7.0 10 ell e6.0 11 e9.6 e9.2 12 e8.8 el4 13 e9 . 0 e!4 14 e8.8 e8.0 15 e8.2 e5.8 16 e7.7 e5.6 17 e7 . 2 e7 . 6 18 e7.2 e7.6 19 e7.0 e7.0 20 e6.8 e7.8 21 e7.0 e23 22 e6.7 e!7 23 e6.7 18 24 e6.7 15 25 e6.4 13 26 e!2 9.9 27 elO 14 28 e22 21 29 e!7 16 30 e!2 38 31 e9.4 TOTAL 301.1 365.1 MEAN 9.71 12.2 MAX 22 38 MIN 6.4 5.6 AC-FT 597 724 CFSM 1.17 1.47 IN. 1.35 1.64 STATISTICS OF MONTHLY MEAN MEAN 11.0 17.9 MAX 16.0 37.4 (WY) 1994 1993 MIN 7.35 5.14 (WY) 1996 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 20 20 14 13 11 10 9.6 8.5 8.5 8.5 13 11 8.5 8.5 8.6 9.2 8.6 7.8 7.7 7.8 7.5 7.5 7.2 7.0 9.7 8.2 8.4 8.3 13 13 16 319.6 10.3 20 7.0 634 1.25 1.44 10 13 9.7 8.8 8.3 8.6 8.1 8.2 8.0 8.5 10 7.9 7.8 7.4 7.2 7.4 7.0 7.7 12 10 77 141 31 64 52 21 14 15 13 10 9.6 623.2 20.1 141 7.0 1240 2.43 2.80 18 11 10 11 11 14 15 13 16 12 11 11 15 11 9.7 8.9 8.5 8.7 9.5 9.3 18 13 11 10 9.8 11 9.8 9.2 —— —— —— 325.4 11.6 18 8.5 645 1.41 1.46 DATA FOR WATER YEARS 1992 13.7 37.0 1993 4.17 1995 FOR 14.1 20.6 1996 1.90 1995 1996 CALBffi 6230.6 17.0 1320 2.4 3.1 12360 2.06 28.03 24 8.4 4.2 7.56 11.6 1997 2.45 1995 MR YEAR Sep 10 May 5 Apr 30 9.2 9.1 9.3 9.5 9.8 9.0 8.5 11 9.2 8.6 8.2 8.6 8.4 7.8 8.0 8.2 8.3 8.5 8.0 7.7 7.2 7.2 7.1 6.9 6.9 6.8 8.3 14 13 9.7 8.1 270.1 8.71 14 6.8 536 1.05 1.21 - 1997, 6.06 8.71 1997 1.75 1995 7.7 10 10 8.4 8.2 8.2 8.2 8.5 8.3 8.0 8.2 7.3 6.4 6.0 6.0 6.1 6.1 6.0 5.6 5.3 5.8 6.3 5.7 5.6 5.7 5.5 5.6 5.6 6.1 5.5 —— 205.9 6.86 10 5.3 408 .83 .93 5.5 5.6 6.2 6.7 6.8 6.7 6.9 7.2 6.9 7.2 7.5 6.7 6.7 7.0 8.2 8.4 7.9 7.0 6.3 5.8 6.2 6.6 6.4 7.4 7.2 7.2 8.3 11 12 15 11 235.5 7.60 15 5.5 467 .92 1.06 9.6 8.5 9.2 8.5 7.5 7.5 7.5 6.9 7.5 6.9 6.3 6.0 7.1 7.5 6.9 6.3 6.5 8.5 7.8 7.7 7.2 6.6 7.7 9.9 8.4 7.5 7.1 6.5 6.4 6.5 —— 224.0 7.47 9.9 6.0 444 .90 1.01 6.9 6.7 6.0 6.1 6.6 8.6 12 12 9.1 8.2 7.5 6.6 6.9 6.0 5.4 6.5 6.7 8.9 14 16 17 16 11 10 8.9 8.0 9.6 13 9.6 9.4 11 290.2 9.36 17 5.4 576 1.13 1.31 8.1 7.0 43 26 11 9.0 7.6 7.0 6.3 8.1 8.6 6.5 5.7 5.5 5.5 5.5 5.8 7.5 5.9 5.2 5.5 29 14 33 32 12 9.7 8.2 7.2 6.3 7.2 358.9 11.6 43 5.2 712 1.40 1.61 5.8 6.7 6.5 6.3 5.6 6.4 7.1 7.5 8.3 6.9 5.4 14 14 10 8.9 8.2 6.9 8.1 7.6 6.4 9.0 9.3 8.3 6.5 6.0 34 15 14 16 10 284.7 9.49 34 5.4 565 1.15 1.28 BY WATER YEAR (WY) 9.48 27.8 1993 1.16 1995 FOR 1997 - 3803 10 141 5 5 395 19 7540 1 17 14 8 6 12.0 41.2 1993 2.31 1994 WATER YEAR .7 .4 Jan 22 .2 Aug 20 .6 Apr 26 Jan 21 .07 Jan 21 .26 .11 .3 .1 8.31 15.8 1996 1.71 1994 14.5 45.5 1993 2.65 1995 11.9 20.2 1993 4.63 1995 WATER YEARS 1992 13.6 24.5 8.33 1320 .72 .77 9040 31.60 9870 1.65 22.39 21 7.0 2.2 Sep Apr Apr sep Sep 32.9 70.6 1996 9.49 1997 - 1997 1993 1994 10 1996 30 1995 27 1995 10 1996 10 1996 e Estimated RIO GRANDE DE LOIZA BASIN 243 50055170 RIO CAGUITAS NEAR CAGUAS, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1992 to 1997. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: June 1992 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1992. REMARKS.-- Sediment Samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 3,820 mg/L September 10, 1996; Minimum daily mean, 1 mg/L July 18-19, 1994. SEDIMENT LOADS: Maximum daily mean,19,100 tons (17,300 tonnes) September 10, 1996; Minimum daily mean, eO.Ol ton (eO.Ol tonne) several days. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 699 mg/L January 22, 1997; Minimum daily mean, 7 mg/L March 4, 1997. SEDIMENT LOADS: Maximum daily mean, 456 tons (413 tonnes) January 21, 1997; Minimum daily mean, 0.16 ton (0.14 tonne) May 22, September 21, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL e!2 e!3 ell elO e9.8 elO e9.7 e9.2 e9.2 ell e9.6 e8.8 e9.0 e8.8 e8.2 e7.7 e7.2 e7.2 e7.0 e6.8 e7.0 e6.7 e6.7 e6.7 e6.4 e!2 elO e22 e!7 e!2 e9.4 301.1 11 11 12 12 12 13 13 14 14 14 15 15 16 16 16 17 17 18 18 19 19 20 21 21 22 25 31 61 59 51 45 ___ e.36 e.40 e.35 e.33 e.33 e.35 e.34 e.34 e.35 e.43 e.38 e.36 e.38 e.38 e.38 e.35 e.34 e.35 e.35 e.35 e.37 e.36 e.37 e.38 e.38 e.80 e.83 e3.6 e2.7 el. 7 el.l 19.79 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER ell ell e8.6 e9.4 elO e9.0 e!4 e7.6 e7.0 e6.0 e9.2 e!4 e!4 e8.0 e5.8 e5.6 e7.6 e7.6 e7.0 e7.8 e23 e!7 18 15 13 9.9 14 21 16 38 --- 365.1 40 35 31 29 30 31 42 37 29 23 27 43 36 28 23 20 20 21 23 25 27 28 29 48 68 72 52 98 59 119 --- ___ el. 2 el.O e.72 e.74 e.81 e.75 el. 6 e.77 6.55 e.37 a. 68 el. 6 el. 4 6.60 e.37 6.31 6.41 6.44 6.44 e.53 el. 6 el. 4 1.4 2.0 2.3 1.9 2.3 5.7 2.5 16 52.39 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 20 20 14 13 11 10 9.6 8.5 8.5 8.5 13 11 8.5 8.5 8.6 9.2 8.6 7.8 7.7 7.8 7.5 7.5 7.2 7.0 9.7 8.2 8.4 8.3 13 13 16 319.6 77 64 83 110 59 29 29 32 40 52 67 80 57 38 29 47 82 49 21 24 30 37 42 31 34 43 66 47 53 48 94 ___ 4.2 3.4 3.3 3.8 1.8 .83 .75 .74 .93 1.2 2.4 2.2 1.3 .86 .66 1.2 1.9 1.0 .44 .49 .61 .75 .82 .59 .93 .95 1.5 1.1 2.2 1.8 5.3 49.95 e Estimated 244 RIO GRANDE BE LOZZA BASIN 50055170 RIO CAG0ITAS NEAR CAOUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 10 13 9.7 8.8 8.3 8.6 8.1 8.2 8.0 8.5 10 7.9 7.8 7.4 7.2 7.4 7.0 7.7 12 10 77 141 31 64 52 21 14 15 13 10 9.6 134 113 122 96 54 43 57 59 42 32 31 32 40 30 20 25 33 30 42 31 588 699 96 229 160 80 59 58 27 17 15 3.6 4.5 3.2 2.3 1.2 1.0 1.2 1.3 .92 .78 .84 .68 .85 .59 .39 .50 .62 .67 1.4 .85 456 365 8.3 60 28 4.5 2.3 2.6 .98 .47 .40 18 11 10 11 11 14 15 13 16 12 11 11 15 11 9.7 8.9 8.5 8.7 9.5 9.3 18 13 11 10 9.8 11 9.8 9.2 —— —— —— 57 34 22 14 12 43 49 58 233 103 26 20 43 26 12 12 12 13 13 14 51 51 43 40 34 30 37 47 3.9 1.0 .61 .40 .38 1.6 2.1 2.1 12 3.5 .80 .60 1.8 .77 .32 .28 .28 .30 .34 .34 3.1 1.8 1.3 1.1 .91 .87 .97 1.2 MEAN DISCHARGE (CFS) 9.2 9.1 9.3 9.5 9.8 9.0 8.5 11 9.2 8.6 8.2 8.6 8.4 7.8 8.0 8.2 8.3 8.5 8.0 7.7 7.2 7.2 7.1 6.9 6.9 6.8 8.3 14 13 9.7 8.1 MEAN CONCEN- TRATION (MG/L) MARCH 45 36 15 7 16 41 42 32 18 10 11 12 15 18 27 35 21 13 28 63 34 12 11 13 21 34 27 88 45 24 24 SEDIMENT DISCHARGE (TONS/DAY) 1.1 .87 .37 .17 .41 1.0 .95 .92 .44 .23 .23 .29 .33 .37 .59 .76 .46 .31 .61 1.3 .67 .23 .21 .24 .40 .62 .62 3.5 1.6 .67 .51 TOTAL 623.2 955.94 325.4 44.67 270.1 20.98 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 245 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) 7.7 10 10 8.4 8.2 8.2 8.2 8.5 8.3 8.0 8.2 7.3 6.4 6.0 6.0 6.1 6.1 6.0 5.6 5.3 5.8 6.3 5.7 5.6 5.7 5.5 5.6 5.6 6.1 5.5 APRIL 31 39 42 20 13 24 41 24 14 29 54 22 12 11 11 13 18 37 66 42 23 13 11 12 16 20 14 12 32 77 MAY .65 1.2 1.2 .46 .29 .54 .90 .55 .31 .62 1.2 .44 .21 .18 .18 .21 .30 .60 1.0 .60 .35 .22 .18 .17 .24 .29 .20 .18 .53 1.1 5.5 5.6 6.2 6.7 6.8 6.7 6.9 7.2 6.9 7.2 7.5 6.7 6.7 7.0 8.2 8.4 7.9 7.0 6.3 5.8 6.2 6.6 6.4 7.4 7.2 7.2 8.3 11 12 15 11 84 73 35 18 34 64 32 18 35 68 47 26 41 74 77 72 67 63 59 50 18 9 16 30 52 63 35 35 42 30 35 1.2 1.1 .58 .32 .63 1.1 .59 .34 .65 1.3 .95 .48 .75 1.4 1.7 1.6 1.4 1.2 1.0 .77 .30 .16 .27 .58 1.0 1.2 .86 1.2 1.4 1.3 1.1 JUNE 9.6 8.5 9.2 8.5 7.5 7.5 7.5 6.9 7.5 6.9 6.3 6.0 7.1 7.5 6.9 6.3 6.5 8.5 7.8 7.7 7.2 6.6 7.7 9.9 8.4 7.5 7.1 6.5 6.4 6.5 ___ 24 15 13 13 16 21 19 16 12 10 11 11 12 13 12 11 11 21 15 12 11 10 15 32 11 18 19 29 34 21 —— .60 .35 .32 .29 .34 .41 .38 .30 .24 .19 .18 .18 .23 .25 .22 .19 .18 .85 .32 .25 .21 .17 .35 .88 .26 .36 .37 .50 .58 .37 TOTAL 205.9 15.10 235.5 28.43 224.0 10.32 246 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE THAT ION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 6.9 6.7 6.0 6.1 6.6 8.6 12 12 9.1 8.2 7.5 6.6 6.9 6.0 5.4 6.5 6.7 8.9 14 16 17 16 11 10 8.9 8.0 9.6 13 9.6 9.4 11 290.2 3803.7 JULY 14 13 14 15 17 16 32 42 36 22 18 15 13 12 13 32 30 31 49 55 53 58 39 32 29 27 33 48 32 41 36 —— .26 .24 .22 .25 .29 .38 1.4 1.4 .90 .49 .37 .28 .23 .19 .19 .71 .54 .86 2.1 2.5 2.6 2.5 1.1 .89 .71 .59 .93 2.0 .84 1.2 1.0 28.16 1398.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 8.1 7.0 43 26 11 9.0 7.6 7.0 6.3 8.1 8.6 6.5 5.7 5.5 5.5 5.5 5.8 7.5 5.9 5.2 5.5 29 14 33 32 12 9.7 8.2 7.2 6.3 7.2 26 21 150 86 29 17 21 15 12 20 23 17 14 12 12 14 16 17 14 12 11 94 43 111 95 38 31 28 23 22 29 .57 .40 63 7.5 .89 .40 .43 .29 .20 .53 .54 .30 .21 .18 .17 .20 .25 .34 .22 .17 .16 12 1.9 27 10 1.3 .84 .63 .45 .38 .60 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 358.9 132.05 5.8 6.7 6.5 6.3 5.6 6.4 7.1 7.5 8.3 6.9 5.4 14 14 10 8.9 8.2 6.9 8.1 7.6 6.4 9.0 9.3 8.3 6.5 6.0 34 15 14 16 10 284.7 20 12 13 13 14 22 26 26 28 24 20 48 51 35 30 27 24 27 26 21 30 32 27 21 19 103 52 49 55 33 .31 .22 .22 .23 .21 .49 .51 .59 .65 .45 .30 2.4 2.2 .99 .74 .61 .46 .62 .53 .36 .76 .81 .62 .36 .31 17 2.2 2.3 2.6 .90 40.95 RXO GRANDE DE LOIZA BASIN 50055170 RIO CAGUXTAS NEAR CAGUAS, PR—Continued MATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 247 DATE DEC 1996 04... JAN 1997 21... 22... FEB 09... MAR 28... TIME 1330 2220 0845 1405 0800 DIS- CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 13 393 323 17 10 SEDI- MENT, SUS- FENCED (MO/L) (80154) 127 4520 2730 367 123 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 4.5 4800 2380 17 3.3 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 57 99 98 99 96 248 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR LOCATION.—Lat 18°14'55", long 66°01'40", Bydrologic Unit 21010005, on left bank, at C. 4 street Villa Blanca housing area at Caguas, 1.8 mi (2.9 km) upstream from Rio Grande de Loiza, and 0.95 mi (1.53 km) northeast from caguas Plaza. DRAINAGE AREA.—11.71 mi 2 (30.33 km*). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—December 1990 to current year. GAGE.—Water-stage recorder. Elevation of gage is 164 ft (50 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. Low-flow affected by pluvial discharge about 50 ft upstream from station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e42 e31 2 e42 629 3 e36 e28 4 636 e27 5 e35 628 6 635 628 7 634 6158 8 e31 675 9 e31 e46 10 e35 636 11 633 644 12 631 641 13 631 637 14 631 627 15 e28 e21 16 626 21 17 625 21 18 625 22 19 624 21 20 623 22 21 624 e45 22 623 e36 23 623 625 24 623 623 25 622 621 26 e37 620 27 e30 e22 28 668 28 29 645 25 30 635 44 31 628 —— TOTAL 992 1052 MEAN 32.0 35.1 MAX 68 158 MIN 22 20 MED 31 28 AC-FT 1970 2090 CFSM 2.73 2.99 IN. 3.15 3.34 STATISTICS OF MONTHLY MEAN MEAN 24.8 33.9 MAX 32.0 56.8 (WY) 1997 1993 MIN 18.7 12.2 (WY) 1996 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS e23 e20 617 e23 622 618 618 e!8 e!7 618 24 18 19 19 18 19 16 17 17 16 18 19 17 19 30 19 18 18 24 25 35 619 20.0 35 16 18 1230 1.71 1.97 DATA 22.2 58.4 1993 8.87 1995 21 46 26 22 20 30 e20 e!8 e!8 621 e29 el 8 e!8 e!7 e20 19 18 21 25 24 80 157 49 75 59 34 32 32 30 25 25 1049 33.8 157 17 25 2080 2.89 3.33 FOR WATER 38.0 120 1992 14.2 1995 46 25 23 23 25 26 31 24 40 32 31 28 44 30 26 19 19 21 22 19 45 23 17 18 18 30 20 20 —— 745 26.6 46 17 25 1480 2.27 2.37 YEARS 1991 18.9 26.6 1997 10.8 1992 20 20 23 24 28 24 19 33 28 26 22 25 25 30 25 24 22 21 21 24 23 27 25 24 34 28 33 50 71 38 35 872 28.1 71 19 25 1730 2.40 2.77 - 1997 14.8 28.1 1997 7.54 1994 FOR 1996 CALENDAR YEAR 21075. 57. 8600 7. 8. 41800 4. 66. 69 20 12 2 6 Sep 10 5 May 31 3 May 28 92 95 631 e77 30 22 19 23 27 29 28 21 27 23 18 19 19 18 17 15 13 14 14 14 14 13 12 12 16 14 14 14 —— 627 20.9 77 12 18 1240 1.78 1.99 12 13 12 12 ell ell e9.7 614 615 620 619 e!5 618 615 614 615 614 e!3 e!3 614 14 14 17 15 17 14 22 21 20 15 18 466.7 15.1 22 9.7 14 926 1.29 1.48 11 10 12 12 11 13 14 15 17 15 11 12 14 10 13 18 21 e46 643 e30 e24 e28 638 623 e!6 e!3 ell 69.5 e!2 ell 533.5 17.8 46 9.5 14 1060 1.52 1.69 69.4 68.4 69.7 69.4 e!2 el 8 e25 el 8 el 8 614 613 elO e!3 elO e8.7 620 614 e!5 621 630 e53 638 617 624 e!3 e!2 623 e45 ell 619 614 565.6 18.2 53 8.4 14 1120 1.56 1.80 ell e9.7 6121 661 e24 e!7 619 e!7 614 626 e20 e!2 e!3 e!3 614 e!3 e20 e!7 e9.5 e9.4 612 189 33 166 88 27 35 615 615 612 e29 1081.6 34.9 189 9.4 17 2150 2.98 3.44 612 612 e20 613 e!2 e!2 ell e9.4 elO e9.3 e8.9 85 70 20 21 14 13 621 615 e22 638 625 628 617 615 e60 e23 660 628 622 726.6 24.2 85 8.9 19 1440 2.07 2.31 , BY WATER YEAR (WY) 16.5 39.8 1993 5.49 1994 24.2 59.8 1993 3.35 1994 22.6 45.6 1996 2.86 1994 FOR 1997 WATER YEAR 9330.0 25.6 189 8.4 9.9 1060 11.37 18510 2.18 29.64 40 21 12 Aug 22 Jul 2 Jun 28 Aug 22 Aug 22 29.7 74.6 1993 4.13 1994 WATER 32 55 11 8600 1 1 25000 23 23250 2 37 42 16 6 33.0 58.0 1995 3.82 1994 YEARS 1991 .1 .2 .9 Sep .3 Jun .4 Jun Sep . 89 Sep .74 .24 .0 85.5 364 1996 8.82 1994 - 1997 1996 1994 10 1996 8 1994 8 1994 10 1996 10 1996 e Estimated 249 RIO QRANDB DE LOIZA BASIN 50055225 RIO CAOVITAS AT VILLA BLANCA AT CAOUAS, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1991 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCBAROE: December 1990 to current year. INSTRUMENTATION.-- USDB-48 sediment sanpler and automatic sediment sampler since 1991. REMARKS.— Sediment samples collected by local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,5700 mg/L September 10, 1996; Minimum daily mean, 3 mg/L August 2, 1997. SEDIMENT LOADS: Maximum daily mean, e34,700 tons (e31,500 tonnes) September 10, 1996; Minimum daily mean, eO.03 ton (eO.02 tonne) June 15, 1994. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 450 mg/L February 2, 1997; Minimum daily mean, 3 mg/L August 2, 1997. SEDIMENT LOADS: Maximum daily mean, e388 tons (e352 tonnes) November 7 , 1996; Minimum daily mean, eO.08 ton (eO.07 tonne) August 2, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCBAROE (MG/L) (TONS/DAY) OCTOBER DISCBAROE (CFS) TRATION DISCBAROE (MG/L) (TONS/DAY) DISCBAROE (CFS) TRATION DISCBAROE (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL e42 e42 e36 e36 e35 e35 e34 e31 e31 e35 e33 e31 e31 e31 e28 e26 e25 e25 e24 e23 e24 e23 e23 e23 e22 e37 e30 e68 e45 e35 e28 992 31 33 35 37 39 41 43 46 48 47 44 43 47 52 58 65 73 80 65 49 38 41 48 53 47 40 34 80 48 43 51 e3.5 e3.7 e3.4 e3.6 e3.7 e3.9 e4.0 e3.8 e4.0 e4.4 e4.0 e3.6 e3.9 e4.4 e4.4 e4.6 e4.9 e5.4 e4.2 e3.1 e2.5 e2.6 e3.0 e3.3 e2.8 e4.0 e2.7 e!5 e5.9 e4.1 e3.9 e31 e29 e28 e27 e28 e28 e!58 e75 e46 e36 e44 e41 e37 e27 e21 21 21 22 21 22 e45 e36 e25 e23 e21 e20 e22 28 25 44 NOVEMBER 60 64 67 71 78 88 319 146 127 121 119 117 114 90 85 84 83 83 82 81 108 82 74 46 41 40 59 97 86 135 130.3 1052 eS.O eS.O e5.2 e5.2 e5.9 e6.6 B388 e30 el6 el2 el7 el3 ell e6.6 e4.9 e4.7 e4.7 e4.8 e4.6 e4.8 el9 e8.6 eS.O e2.9 e2.3 e2.2 e4.0 7.3 5.8 22 634.1 e23 e20 el7 e23 e22 el8 el8 el8 el7 el8 24 18 19 19 18 19 16 17 17 16 18 19 17 19 30 19 18 18 24 25 35 119 79 50 32 39 57 70 61 70 47 93 93 86 79 73 87 75 73 139 78 79 60 41 55 113 89 75 95 100 85 83 e7.5 e4.4 e2.3 e2.0 e2.2 e2.9 e3.5 e3.0 e3.2 e2.2 6.1 4.6 4.3 4.0 3.5 4.5 3.3 3.4 6.5 3.5 3.9 3.1 1.9 2.9 9.6 4.5 3.6 4.9 6.9 5.9 10 619 134.1 e Estimated 250 RIO GRANDE DE LOZZA BASIN 50055225 RIO CAGOITAS AT VILLA BLANCA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN MEAN MEAN iN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT iRGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE !) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 21 46 26 22 20 30 e20 e!8 e!8 a21 e29 e!8 e!8 a 17 e20 19 18 21 25 24 80 157 49 75 59 34 32 32 30 25 25 86 119 64 25 20 63 59 55 65 77 92 111 134 161 188 146 99 81 89 93 166 271 125 161 159 106 78 84 106 93 90 4.8 21 4.6 1.5 1.1 7.5 e3.0 e2.7 e3.2 e4.4 e7.2 e5.4 e6.5 e7.4 elO 7.5 4.7 4.8 6.0 6.1 62 144 17 39 27 9.7 6.7 7.5 8.6 6.2 6.1 FEBRUARY 46 25 23 23 25 26 31 24 40 32 31 28 44 30 26 19 19 21 22 19 45 23 17 18 18 30 20 20 ___ ___ ___ 299 450 406 380 360 306 128 96 68 21 55 34 108 93 33 29 39 50 75 80 87 61 61 60 60 130 130 107 ___ --_ 46 31 26 23 24 22 11 6.2 7.5 1.8 4.8 2.5 14 7.8 2.3 1.5 2.0 2.9 4.5 4.2 11 3.8 2.7 2.9 2.9 11 6.9 5.9 —— ___ _-_ MARCH 20 20 23 24 28 24 19 33 28 26 22 25 25 30 25 24 22 21 21 24 23 27 25 24 34 28 33 50 71 38 35 90 84 145 144 117 100 86 106 86 67 54 70 99 84 50 41 34 28 23 20 21 23 25 24 75 32 76 120 150 103 110 4.8 4.6 8.9 9.3 8.9 6.5 4.3 9.8 6.4 4.8 3.2 4.9 6.6 6.7 3.4 2.6 2.0 1.6 1.3 1.3 1.3 1.7 1.7 1.6 7.6 2.4 7.1 17 32 11 10 1049 453.2 745 292.1 872 195.3 a Estimated RXO GRANDE DE LOXZA BASIN 50055225 RXO CAGUXTAS AT VILLA BLANCA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 251 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATXON DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e31 e77 30 22 19 23 27 29 28 21 27 23 18 19 19 18 17 15 13 14 14 14 14 13 12 12 16 14 14 14 —— APRXL 103 168 131 85 57 80 83 23 16 17 55 73 40 23 27 37 47 38 28 21 19 18 18 17 16 16 36 47 29 24 ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATXON DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CPS) MAY e8.7 e77 11 5.0 2.9 5.1 6.3 1.7 1.2 .95 4.5 4.6 1.9 1.2 1.3 1.8 2.1 1.5 .96 .79 .73 .70 .69 .62 .54 .49 1.9 1.8 1.1 .91 ___ 12 13 12 12 ell ell e9.7 e!4 elS e20 e!9 elS e!8 elS e!4 e!5 el4 e!3 e!3 e!4 14 14 17 15 17 14 22 21 20 15 18 22 30 17 18 18 19 20 65 102 81 92 60 88 54 62 225 31 15 13 12 14 15 39 67 71 24 51 77 62 57 75 .73 1.2 .57 .57 e.55 e.54 e.50 e5.7 e!2 e4.3 elO e2.6 ell e6.8 e2.8 e!55 e!8 e2.8 e2.3 el. 3 .51 .59 2.7 2.8 3.4 .93 5.2 5.2 4.2 2.3 4.1 11 10 12 12 11 13 14 15 17 15 11 12 14 10 13 18 21 e46 e43 e30 e24 e28 e38 e23 e!6 e!3 ell e9.5 e!2 ell—— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 11 10 12 12 11 13 14 15 17 15 11 12 14 10 13 18 21 e46 e43 e30 e24 828 838 823 e!6 e!3 ell e9.5 e!2 ell 97 91 85 73 60 53 69 94 128 155 184 211 187 155 128 98 72 125 115 57 84 97 108 123 119 110 101 91 81 72 2.8 2.5 2.9 2.3 1.7 1.9 2.5 3.8 5.8 6.3 5.5 6.8 6.9 4.3 4.5 4.7 4.5 e!9 e!4 e4.9 e5.7 e6.9 e!2 e7.6 e5.1 e3.8 e3.0 e2.3 e2.6 e2.1 TOTAL 627 149.98 466.7 271.19 533.5 158.7 e Estimated 252 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) e9.4 e8.4 e9.7 e9.4 e!2 e!8 e25 e!8 e!8 e!4 e!3 elO e!3 elO e8.7 e20 e!4 e!5 e21 e30 e53 e38 e!7 e24 e!3 e!2 e23 e45 ell e!9 e!4 JULY 55 38 40 42 38 71 70 85 105 99 89 53 29 15 8 34 63 70 82 82 124 90 35 72 25 20 76 124 41 62 26 TOTAL 565.6 —— YEAR e 9330.0 Estimated el e el el el e4 e7 e4 e5 e3 e3 .4 .86 .1 .1 .2 .2 .8 .1 .0 .6 .2 el. 5 el e e e3 e2 e3 e5 e7 e25 e!4 .0 .42 .19 .7 .4 .2 .2 .3 el. 9 e6 e e e6 e35 el e4 e 154 3995 .1 .94 .63 .2 .2 .1 .93 .47 .86 MEAN DISCHARGE (CFS) ell e9.7 e!21 e61 e24 e!7 e!9 e!7 e!4 e26 e20 e!2 e!3 e!3 e!4 e!3 e20 e!7 e9.5 e9.4 e!2 189 33 166 88 27 35 e!5 e!5 e!2 e29 1081.6 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST ell e9.7 •121 e61 e24 e!7 e!9 e!7 e!4 e26 e20 e!2 e!3 e!3 e!4 e!3 e20 e!7 e9.5 e9.4 e!2 189 33 166 88 27 35 elS elS e!2 e29 5 3 358 158 84 65 67 100 64 86 142 138 135 134 135 138 162 195 222 134 67 243 103 168 199 96 99 66 68 43 85 e.14 e.08 e295 e33 eS.S e2.9 e3.7 e4.7 e2.4 e8.7 e7.5 e4.5 e4.7 e4.8 eS.l e4.8 e8.8 e8.8 e5.7 e3.4 e2.0 314 9.6 163 55 7.1 16 e2.8 e3.1 el. 4 eS.S 996.72 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) ( (MG/L) (TONS/DAY) SEPTEMBER e!2 e!2 e20 e!3 e!2 e!2 ell e9.4 elO e9.3 e8.9 85 70 20 21 14 13 e21 elS e22 e38 e25 e28 e!7 elS e60 e23 e60 e28 e22 45 37 66 82 62 52 66 87 91 50 32 335 286 81 68 47 62 71 40 40 39 38 38 49 103 80 50 50 56 61 el. 4 el. 2 e4.4 e3.3 el. 9 el. 7 e2.0 e2.4 e2.6 el. 3 el. 2 208 126 4.5 4.3 1.7 2.2 e4.0 el. 4 e2.4 e4.0 e2.6 e2.8 e2.2 e4.2 e!3 e3.1 eS.l e4.2 e3.6 726.6 425.7 RIO GRANDE DE LOIZA BASIN 253 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGOAS, PR—Continued MATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE JUL 1997 28... AU6 22... DIS- CHARGE, INST. CUBIC FEET TIME PER SECOND (00061) 1002 287 1315 872 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1760 1940 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 1370 4570 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 48 41 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 54 50 SED. SUSP. FALL DIAM. H FINER THAN .008 MM (70328) 58 56 DATE JUL 1997 28... AUG 22... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 70 71 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 81 81 SED. SUSP. SIEVE DZAM. % FINER THAN .062 MM (70331) 93 95 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 100 SED* SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 SED. SUSP. SIEVE DZAM. % FINER THAN 1.00 MM (70335) 100 100 254 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE NOV 1996 10... FEB 1997 03... AUG 03... 03... 19... 24... 25... SEP 13... TIME 1431 1528 1845 2300 1500 1830 0030 1645 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 30 26 391 218 8.1 877 223 SEDI- MENT, SUS- PENDED (MG/L) (80154) 122 398 900 2500 241 225 314 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 9.9 28 950 1470 5.3 533 189 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 96 99 98 100 86 96 99 304 1590 1300 99 RIO GRANDE DE LOIZA BASIN 50055250 RIO CAGUITAS AT HIGHWAY 30 AT CAGUAS, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°15'11", long 66°01'26", at Highway 30 bridge, and 0.8 mi (1.3 km) east of Caguas plaza. DRAINAGE AREA.—14.1 mi 2 (36.5 km2 ). PERZOD OF RECORD.—Water years 1972 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 255 DATE NOV 1996 07... PEB 1997 10... MAY 16... SEP 02... NOV 07 PEB 10 MAY 16 SEP 02 NOV 07 PEB 10 MAY 16 SEP 02 NOV 07 FEB 10 MAY DZS- PH OXYGEN, OXYGEN COLZ- CHARGE, SPE- WATER DZS- DEMAND, FORM, STREP - INST. CZFZC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FZELD TEMPER- TOR- OXYGEN, (PER- ZCAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BZD- DZS- CENT (HIGH UM-MF (COLS. TZME PER ANCE ARD WATER ZTY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATZON) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0945 20 446 6.9 26.0 5.3 6.3 77 16 36000 4600 0850 19 499 6.7 22.5 14 4.0 45 19 K170000 27000 1025 14 509 6.8 26.5 72 3.5 43 65 47000 77000 0755 9.8 514 6.9 27.0 5.9 3.9 49 <10 K8100 2900 ALKA- HARD- MAGNE- SODIUM POTAS- LINZTY CHLO- DATE 1996 ... 1997 ... ... ... DATE 1996 ... 1997 ... ... DATE 1996 ... 1997 ... 16... SEP 02 K = ... NESS TOTAL (MG/L AS CACO3) (00900) 160 — 160 160 FLUO- RZDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.17 0.14 NZTRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.50 2.3 3.4 1.8 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 44 -- 43 44 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 28 — 29 36 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.2 3.1 3.6 2.2 SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 -- 13 13 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 274 — 307 314 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.2 14 16 9.7 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 25 -- 34 31 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 15.1 — 11.3 8.34 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.140 0.370 0.600 0.310 AD- SORP- TION RATIO (00931) 0.9 — 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 26 16 186 12 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 — 3.4 3.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.570 0.730 0.120 0.290 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 141 190 160 180 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.110 0.140 0.050 0.160 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 60 -- 40 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.680 0.880 0.170 0.450 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 43 — 52 39 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.330 1.70 2.00 1.00 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 -- 1 — RIDE, DIS- SOLVED (MG/L AS CL) (00940) 34 — 36 39 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.60 1.5 0.71 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 — 20 — non-ideal count 256 RIO ORANDE DE LOIZA BASIN 50055250 RIO CAOUITAS AT BIOBMAY 30 AT CAOUAS, PR—Continued MATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 07... FEB 1997 10... MAY 16... SEP 02... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 960 780 320 210 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 20 <0.010 0.03 <0.01 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR 257 LOCATION.--Lat 18°15'32", long 66°02'24", Bydrologic Unit 21010005, on left bank, in the Bairoa Housing Area, 1.6 mi (2.6 Ion) northwest of Plaza de Caguas, 4.1 mi (6.6 Ion) east of Plaza de Aguas Buenas, and 0.9 mi (1.4 km) northwest of Escuela Pepita Garriga. DRAINAGE AREA.—5.08 mi 2 (13.15 km2 ). MATER-DISCHARGE RECORDS PERIOD OF RECORD.—November 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 131 ft (40 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. Mean daily discharge affected by domestic discharge from nearby station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEE MAR MAY JUN JUL AUG SEP 1 ell e7 . 0 2 elO e8.0 3 ell e6.2 4 e9.8 e6.4 5 e9.4 e6.2 6 e9.0 e6.2 7 e9.0 elO 8 e9.4 e9.6 9 ell e7 . 2 10 e20 e6.0 11 ell e25 12 e8.4 e47 13 e8.0 e30 14 e8.0 e!2 15 e8.2 e9.4 16 e7.4 e8.2 17 e7 . 0 elO 18 e7 . 0 e8 . 0 19 e7.2 e8.8 20 e6.6 e8.6 21 e6.4 e!6 22 e6.2 elO 23 e6.0 e8.4 24 e5.6 e7.4 25 e5.4 e6.8 26 e8.8 e6.4 27 ell e6.0 28 e7.8 e7.4 29 e6.4 e6.6 30 e6.2 e9.2 31 e6.4 TOTAL 264.6 324.0 MEAN 8.54 10.8 MAX 20 47 MIN 5.4 6.0 AC-FT 525 643 CFSM 1.68 2.13 IN. 1.94 2.37 e9.0 e7.0 e6.2 e5.8 e5.8 e6.2 e8.6 e6.0 e5.6 e5.2 e39 ell elO e8.6 e7.6 e7.4 e7.0 e6.6 e6.2 e6.0 e6.0 e5.6 e5.8 e6.1 e6.0 e5.8 e6.0 e5.6 elO e!5 e8.0 254.7 8.22 39 5.2 505 1.62 1.87 67.4 68.0 ell 69.2 68.4 68.0 67.8 67.6 67.4 e7.4 e!7 e9.0 e8.0 e7.4 e7.4 e7.0 e7.2 e7.3 e7.4 613 e22 e32 e9.8 e9.4 68.6 67.6 66.2 69.0 67.0 66.2 66.0 296.7 9.57 32 6.0 589 1.88 2.17 e!9 622 e9.0 e7.6 e7.4 67.2 67.0 66.4 69.8 67.2 68.2 68.0 e!4 elO e8.2 e8.0 e7.0 e6.2 e6.6 e6.4 a9.2 a8.6 a9.2 66.8 e7.2 e8.2 e6.4 e6.0 —— —— 246.8 8.81 22 6.0 490 1.74 1.81 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1991 MEAN 9.61 10.1 MAX 25.3 22.2 (WY) 1991 1993 MIN 4.30 5.71 (WY) 1992 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 8.84 19.7 1993 4.63 1992 FOR 9.10 14.7 1996 4.12 1995 5.63 8.81 1997 3.42 1994 e5.6 e5.6 66.0 e6.0 65.8 65.8 65.4 65.8 65.8 65.4 64.9 65. 0 64.9 64.6 e6.6 67.2 65.2 65.2 65.4 64.8 64.6 64.3 64.2 64.2 63.9 63.9 63.9 64.7 e4.7 e4.3 e4.0 157.7 5.09 7.2 3.9 313 1.00 1.15 - 1997 4.31 5.53 1996 2.87 1994 1996 CALENDAR YEAR 5356.9 14.6 1700 2.9 3.1 10630 2.88 39.23 19 6.1 3.5 Sep 10 Jul 6 Jul 1 64.0 625 elO e7.8 66.6 66.0 65.4 65.4 65.4 65.0 65.6 65. 0 65.6 65. 1 64.9 e4.8 eS.O e4.8 e4.8 a4.6 e4.8 e4.6 e4.5 e4.5 64.5 e4.4 e4.7 64.8 e4.2 64.1 ___ 175.9 5.86 25 4.0 349 1.15 1.29 64.0 63.9 e3.9 63.9 a3. 8 63.8 63.9 64.4 64.0 67.0 e4.6 e5.6 a4.5 e4.1 e6.0 e5.8 e!9 e5.2 e4.4 e4.4 e4.7 e4.0 a3.9 e4.0 a3.9 e3.7 e5.6 e6.6 612 eS.O e6.2 168.8 5.45 19 3.7 335 1.07 1.24 e6.2 e!2 627 e9.0 e6.6 e6.0 e5.6 65. 0 64.9 64.6 65. 0 64.6 66.6 69.6 66.0 64.3 64.1 64.5 64.3 64.3 64.1 64.1 64.1 64.3 64.1 64.0 64.0 63.9 63.8 64.0 —— 180.6 6.02 27 3.8 358 1.19 1.32 63.7 a3. 4 63.3 63.3 63.3 63.2 63.3 63.8 63.7 63.5 63.3 63.4 63.5 63.3 63.2 63.5 63.3 a20 e24 elO 616 e!2 e5.4 e6.8 e4.7 e4.4 e5.6 e5.8 64.1 66.4 65. 0 188.2 6.07 24 3.2 373 1.20 1.38 e3.8 64.6 688 629 615 68.9 e7.8 e6.0 eS.O e7.4 e6.0 e5. 0 e4.3 4.1 3.9 3.9 4.6 4.4 3.9 3.8 elO a54 e8.1 e33 e!2 e7.6 e6.8 e5.6 eS.O e4.7 e5.4 371.6 12.0 88 3.8 737 2.36 2.72 e4.8 65.2 64.1 64.1 63.8 63.8 63.8 69.2 64.5 63.8 63.5 63.8 63.5 64.0 63.5 a4.9 4.2 5.6 3.4 4.7 10 6.9 5.0 3.6 3.3 10 6.7 7.8 6.6 5.5 153.6 5.12 10 3.3 305 1.01 1.12 , BY WATER YEAR (WY) 4.93 9.23 1996 2.61 1992 FOR 1997 2783 7 88 3 3 260 9 5520 1 20 11 6 3 6.05 12.5 1993 2.91 1994 WATER YEAR .2 .63 Aug 3 .2 Jul 6 .4 Jul 1 Aug 3 .25 Aug 3 .50 .38 .0 .9 5.28 8.64 1993 2.72 1995 8.06 16.5 1991 4.35 1994 WATER 8 14 4 1700 1 1 6190 18 6100 1 22 12 4 2 8.78 17.7 1996 4.09 1991 YEARS 1991 .42 .5 .52 Sep .3 Jul .6 Jun Sep .16 Sep .66 .51 .6 .8 20.3 76.9 1996 4.50 1991 - 1997 1996 1994 10 1996 2 1995 30 1995 10 1996 10 1996 e Estimated 258 RIO ORANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1991 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1994 to current year. INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler since 1991. REMARKS:-- Sediment samples were collected by a local observer on a weekly. During high flows events sediment samples were collected and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 7,040 mg/L September 10, 1996; Minimum daily mean, 2 mg/L Several years. SEDIMENT LOADS: Maximum daily mean, 37,900 tons (34,300 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.01 tonne) Several years. EXTREME FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 336 mg/L January 24, 1997; Minimum daily mean, 3 mg/L Several days. SEDIMENT LOADS: Maximum daily mean, 31 tons (28 tonnes) August 4, 1997; Minimum daily mean, 0.03 ton (0.03 tonne) Several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 ell elO ell e9.8 e9.4 e9.0 e9.0 e9.4 ell e20 ell e8.4 eS.O e8.0 e8.2 e7.4 e7.0 e7.0 e7.2 e6.6 e6.4 e6.2 e6.0 e5.6 e5.4 e8.8 ell e7.8 e6.4 e6.2 e6.4 22 .67 18 12 14 18 12 7 4 3 17 24 17 13 11 11 10 17 34 39 42 .52 .35 .40 .47 .30 .17 .11 .09 .77 .99 .45 .28 .25 .23 .22 .34 .63 .76 .77 54 e.94 71 el. 2 84 el. 4 94 el. 5 77 el.l 57 el.l 42 el.l 35 e.86 44 e.83 53 e.90 49 e.83 e7.0 e8.0 e6.2 e6.4 e6.2 e6.2 elO e9.6 e7.2 e6.0 e25 e47 e30 e!2 e9.4 e8.2 elO eB.O e8.8 e8.6 e!6 elO e8.4 e7.4 e6.8 e6.4 e6.0 e7.4 e6.6 e9.2 ___ CONCEN- TRATION DISCHARGE (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER e7.0 eS.O e6.2 e6.4 e6.2 e6.2 elO e9.6 e7.2 e6.0 e25 e47 e30 e!2 e9.4 e8.2 elO eB.O e8.8 e8.6 e!6 elO e8.4 e7.4 e6.8 e6.4 e6.0 e7.4 e6.6 e9.2 45 44 45 63 89 82 66 54 44 36 59 182 284 115 52 58 74 51 34 37 45 56 68 75 49 31 21 30 51 59 e.82 e.90 e.86 el.l el. 5 el. 4 el. 4 el. 4 e.99 e.63 e2.5 el 8 e29 e6.6 el. 5 el. 4 el. 8 el. 3 e.78 e.87 el. 5 el. 9 el. 7 el. 6 e.95 e.55 e.34 e.55 e.95 el. 2 e9.0 e7.0 e6.2 e5.8 e5.8 e6.2 e8.6 e6.0 e5.6 e5.2 e39 ell elO e8.6 •7.6 e7.4 e7.0 e6.6 e6.2 e6.0 e6.0 e5.6 e5.8 e6.1 e6.0 e5.8 e6.0 e5.6 elO elS eB.O 61 55 48 42 24 12 10 21 13 8 71 28 11 12 13 10 7 6 6 7 8 9 11 12 14 17 19 2? 49 103 82 el. 5 el. 2 e.86 e.68 e.38 e.20 e.20 e.41 e.21 e.12 e4.9 e2.3 e.30 e.30 e.29 e.20 e.13 e.ll e.10 e.ll e.13 e.14 e.16 e.20 e.23 e.26 e.31 e.36 el.l e3.5 e2.5 TOTAL 264.6 20.53 324.0 85.99 254.7 23.39 e Estimated RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY 259 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e7.4 eS.O ell e9.2 e8.4 eS.O e7.8 e7.6 e7.4 e7.4 e!7 e9.0 eS.O e7.4 e7.4 e7.0 e7.2 e7.3 e7.4 e!3 e22 e32 e9.8 e9.4 e8.6 e7.6 e6.2 e9.0 e7.0 e6.2 e6.0 55 37 25 17 12 9 7 7 7 7 32 45 8 5 4 5 6 7 8 13 50 196 299 336 129 34 43 75 73 68 61 el. 2 .77 .63 .46 .29 .20 .15 .14 .14 .14 el. 2 el. 6 .18 .10 .08 .09 .11 .13 .17 .35 e2.5 e!5 e!5 e8.7 e3.2 e.74 e.79 el. 5 el. 6 el. 2 el.O e!9 e22 e9.0 e7.6 e7.4 e7.2 e7.0 e6.4 e9.8 e7.2 e8.2 eS.O e!4 elO e8.2 eS.O e7.0 e6.2 e6.6 e6.4 e9;2 e8.6 e9.2 e6.8 e7.2 e8.2 e6.4 e6.0 —— e!9 e22 e9.0 e7.6 e7.4 e7.2 e7.0 e6.4 e9.8 e7.2 e8.2 eS.O e!4 elO e8.2 eS.O e7.0 e6.2 e6.6 e6.4 e9;2 e8.6 e9.2 e6.8 e7.2 e8.2 e6.4 e6.0 55 49 43 26 14 16 22 42 65 28 10 9 10 11 13 16 18 18 20 44 101 64 29 42 82 88 76 50 el. 7 e2.7 el. 7 e.59 e.29 e.31 e.43 e.75 el. 4 e.66 e.21 e.19 e.29 e.37 e.33 e.34 e.36 e.33 e.35 e.77 e2.1 el. 5 e.70 e.89 el. 5 el. 8 el. 5 e.83 296.7 59.36 246.8 24.89 MEAN DISCHARGE (CFS) e5.6 e5.6 e6.0 e6.0 e5.8 e5.8 e5.4 e5.8 e5.8 e5.4 e4.9 eS.O e4.9 e4.6 e6.6 e7.2 e5.2 e5.2 e5.4 e4.8 e4.6 e4.3 e4.2 e4.2 e3.9 e3.9 e3.9 e4.7 e4.7 e4.3 e4.0 157.7 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 30 «.47 21 «.32 35 e.55 62 el.O 75 el. 2 79 «1.2 74 el.l 67 el.O 60 51 30 16 11 8 7 8 7 6 8 , 11 10 8 6 7 8 5 3 5 15 31 27 .94 .77 .41 .22 .14 .10 .11 .14 .12 .09 .12 .15 .13 .09 .07 .08 .09 .05 .03 .06 .19 .38 .30 11.62 e Estimated 260 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY}, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e4.0 e25 elO e7.8 e6.6 e6.0 e5.4 e5.4 e5,4 eS.O e5.6 eS.O e5.6 eS.l e4.9 e4.8 eS.O e4.8 e4.8 e4.6 e4.8 e4.6 e4.5 e4.5 e4.5 e4.4 e4.7 e4.8 e4.2 e4.1 ___ APRIL 23 e.25 78 e3.0 39 e2.1 10 9 9 9 10 9 8 9 10 11 10 9 14 27 25 17 11 5 3 5 13 14 12 15 18 9 6 .23 .18 .15 .14 .14 .13 .12 .13 .14 .15 .14 .12 .19 .37 .32 .21 .14 .07 .03 .06 .16 .17 .14 .20 .23 .10 .07 —— —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY e4.0 e3.9 e3.9 e3.9 e3.8 e3.8 e3.9 e4.4 e4.0 e7.0 e4.6 e5.6 e4.5 e4.1 e6.0 e5.8 e!9 e5.2 e4.4 e4.4 e4.7 e4.0 e3.9 e4.0 e3.9 e3.7 e5.6 e6.6 e!2 eS.O e6.2 5 8 17 37 68 111 83 49 38 31 28 33 41 40 38 54 89 53 51 73 50 27 23 22 22 21 20 22 23 21 17 e.05 e.08 e.18 e.39 e.71 el.l e.86 e.55 e.43 e.45 e.42 e.46 e.55 e.46 e.51 e.69 e2.5 el. 7 e.65 e.87 e.61 e.32 e.24 e.24 e.23 e.21 e.25 e.35 e.57 e.55 e.33 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE e6.2 e!2 e27 e9.0 e6.6 e6.0 e5.6 eS.O e4.9 e4.6 eS.O e4.6 e6.6 e9.6 e6.0 e4.3 e4.1 e4.5 e4.3 e4.3 e4.1 e4.1 e4.1 e4.3 e4.1 e4.0 e4.0 e3.9 e3.8 e4.0 ___ 14 13 28 83 19 15 16 19 19 19 14 9 9 10 11 12 10 9 10 12 11 9 8 7 7 9 12 11 8 19 e.24 e.30 el. 7 e4.1 e.41 e.25 e.26 e.26 e.26 e.25 e.18 e.12 e.13 e.21 e.22 e.16 e.12 e.ll e.12 e.13 e.12 e.10 e.09 e.09 e.08 e.10 e.13 e.ll e.09 e.26 175.9 9.58 168.8 17.51 180.6 10.70 e Estimated RIO ORANDE DE LOIZA BASIN 261 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) AUGUST DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) e3.7 e3.4 e3.3 e3.3 e3.3 e3.2 e3.3 e3.8 e3.7 e3.5 e3.3 e3.4 e3.5 e3.3 e3.2 e3.5 e3.3 e20 e24 elO el6 el2 e5.4 e6.8 e4.7 e4.4 e5.6 e5.8 e4.1 e6.4 eS.O JULY 18 10 12 12 10 9 8 7 10 5 5 6 7 5 3 17 10 10 54 82 26 17 13 9 7 7 10 16 77 319 203 TOTAL 188.2 —— YEAR e 2783.2 Estimated e.18 e.09 e.ll e.10 e.09 e.08 e.07 e.08 e.10 e.05 e.05 e.05 e.06 e.04 e.03 e.16 e.09 6.13 e2.3 e3.8 6.87 6.64 e.28 6.15 e.10 e.09 6.13 e.25 e.96 64.6 e3.2 18.93 394.98 MEAN DISCHARGE (CFS) 63.8 64.6 688 629 e!5 e8.9 e7.8 e6.0 eS.O e7.4 66.0 65.0 64.3 4.1 3.9 3.9 4.6 4.4 3.9 3.8 elO e54 68.1 e33 e!2 e7.6 e6.8 e5.6 eS.O 64.7 65.4 371.6 e3.8 e4.6 e88 e29 e!5 e8.9 e7.8 e6.0 eS.O e7.4 e6.0 eS.O e4.3 4.1 3.9 3.9 4.6 4.4 3.9 3.8 elO e54 e8.1 e33 e!2 e7.6 e6.8 e5.6 eS.O e4.7 e5.4 78 47 208 174 25 6 4 4 5 7 9 13 23 18 9 8 18 13 5 4 19 162 86 37 96 18 14 17 15 12 10 e.93 e.54 e26 e31 el. 5 e.20 e.09 e.08 e.07 e.ll e.15 e.19 e.28 e.20 e.10 e.08 e.24 e.16 e.05 e.04 e.41 e!4 e8.4 e2.7 e6.1 e.48 e.26 e.28 e.22 e.16 e.13 MEAN DISCHARGE (CFS) k>i e4.8 e5.2 e4.1 e4.1 e3.8 e3.8 e3.8 e9.2 e4.5 e3.8 e3.5 e3.8 e3.5 e4.0 e3.5 e4.9 4.2 5.6 3.4 4.7 10 6.9 5.0 3.6 3.3 10 6.7 7.8 6.6 5.5 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 8 .11 6 5 5 4 4 3 11 23 4 13 81 88 56 37 .09 .06 .05 .04 .04 .03 .24 .44 .04 .12 .81 .86 .57 .37 29 e.36 24 .27 49 1.0 22 .21 27 .48 57 2.2 36 .93 31 .44 11 .11 9 .08 107 4.7 42 .77 46 1.3 24 .47 10 .14 95.15 153.6 17.33 262 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 24... NOV 13... JAN 1997 28... FEE 09... MAY 06... JUL 30... AUG 04... SEP 26... TIME 1545 1640 1633 1118 1610 1530 1245 1700 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) e5.6 e30 e9.0 e9.8 83.8 e6.4 e29 14 SEDI- MENT, SUS- PENDED (MG/L) (80154) 99 302 854 81 129 458 95 212 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) el. 5 825 e21 e2.1 el. 3 e7.9 e7.4 8.0 SED. SUSP. SIEVE DIAM. «6 FINER THAN .062 MM (70331) 96 98 99 91 99 100 96 98 e Estimated RIO ORANDE DE LOIZA BASIN 263 50055400 RIO BAIROA NEAR CAGUAS, PR MATER-QUALITY RECORDS LOCATION.—Lat 18°15'28", long 66°02'13", at bridge on Highway 1, about 2.5 mi (4.0 km) upstream from Rio Orande de Loiza, and 1.4 mi (2.3 km) north of Caguas plaza. DRAINAGE AREA.—5.4 mi' (14.0 km2 ). PERIOD OF RECORD.—Water years 1958, 1962-66, 1973-74, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PB OXYGEN, OXYGEN COLI- CHAROE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CBEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. HATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1200 -- 386 7.0 25.5 4.5 8.4 101 <10 2700 7200 .997 1035 6.1 395 6.7 23.0 1.2 5.1 57 14 21000 2200 1100 3.1 482 7.0 26.0 20 2.8 34 11 K7100 670 0930 2.8 454 6.8 27.0 17 3.2 40 <10 K63000 2800 ALKA- DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 150 — 160 160 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — 0.21 0.16 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.83 0.76 1.2 0.80 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 36 — 39 39 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 27 -- 31 30 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.1 1.9 2.3 1.9 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 14 -- 16 15 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 238 — 283 263 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 9.4 8.6 10 8.3 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 23 — 26 25 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) -- — 2.34 1.97 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.340 0.270 0.380 0.310 SODIUM AD- SORP- TION RATIO (00931) 0.8 — 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 20 6 30 25 ARSENIC TOTAL (UG/L AS AS) (01002) 2 __ <1 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.8 _- 4.4 4.1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.20 1.10 0.890 0.980 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 __ <100 — LINXTY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 142 180 190 160 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.050 0.100 0.180 0.100 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.30 1.20 1.10 1.10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 _- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 18 — 15 18 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.200 0.330 0.800 0.260 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 2 — 1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 31 -- 38 35 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.62 0.43 0.45 0.54 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 — 10 — K » non- ideal count 264 RIO GRANDE DE LOIZA BASIN 50055400 RIO BAIROA NEAR CAGUAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UQ/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 660 510 150 <0.10 130 <0.10 <1 <1 <1 <1 20 <0.010 10 <0.010 0.05 0.03 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR 265 LOCATION.--Lat 18°14'02", long 65°53'07", Hydrologic Unit 21010005, on left bank, 2.43 ml (3.91 km) northeast of Plaza de Juncos, 1.3 mi (2.1 km) southeast of Escuela La Placita and 0.35 ml (0.56 km ) southwest of El Mango. DRAINAGE AREA.--22.3 mi 2 (57.8 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—March 1990 to current year. GAGE.--Water-stage recorder. Elevation of gage is 230 ft (70 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. Low-flow is affected by sewage discharges from a water treatment plant, 0.60 mi (0.96 m) upstream from gaging station since 1990. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT JAN MAR APR JUL AUG SEP 1 20 28 2 18 51 3 17 22 4 22 19 5 21 19 6 17 30 7 25 414 8 21 46 9 22 40 10 41 26 11 31 132 12 19 506 13 17 231 14 16 43 15 15 30 16 15 32 17 14 47 18 13 45 19 13 70 20 13 43 21 12 40 22 12 57 23 12 39 24 12 60 25 20 34 26 49 21 27 32 18 28 37 19 29 51 18 30 19 39 31 15 —— TOTAL 661 2219 MEAN 21.3 74.0 MAX 51 506 MIN 12 18 AC-FT 1310 4400 CFSM .96 3.32 IN. 1.10 3.70 STATISTICS OF MONTHLY MEAN MEAN 43.7 66.7 MAX 161 109 (WY) 1991 1992 MIN 4.01 13 . 6 (WY) 1993 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 31 27 22 20 19 18 17 17 16 16 38 27 18 16 15 16 16 15 14 14 14 14 14 13 15 14 15 16 29 46 27 609 19.6 46 13 1210 .88 1.02 17 15 14 13 12 12 12 13 14 12 12 11 10 10 9.8 9.5 9.1 8.8 8.8 13 23 elOS 632 633 620 el2 e9.7 619 615 68.4 68.6 521.7 16.8 105 8.4 1030 .75 .87 DATA FOR WATER 29.8 59.0 1991 12.0 1994 FOR 38.8 103 1996 6.34 1995 6270 6210 656 616 621 652 639 624 628 625 620 621 668 640 626 el 8 621 e!7 e!7 e!4 621 623 647 e!7 626 628 e!3 11 ___ ___ —— 1189 42.5 270 11 2360 1.90 1.98 YEARS 1990 32.3 66.7 1995 10.4 1993 11 11 15 19 17 13 12 12 13 11 10 11 11 10 10 12 12 11 11 9.9 9.5 9.6 9.1 8.8 8.6 8.6 8.0 8.5 13 11 9.5 346.1 11.2 19 8.0 686 .50 .58 - 1997 12.1 18.1 1991 5.63 1993 1996 CALENDAR YEAR 20769. 56. 4040 4. 5. 41200 2. 34. 80 15 5. 5 7 Sep 10 1 Aug 13 1 May 24 54 65 7 9.5 53 39 10 8.0 7.8 6.9 6.7 6.5 6.3 6.0 6.1 6.2 6.1 6.1 5.8 5.8 5.8 5.7 5.7 5.6 5.5 .9 .8 .8 .9 .8 5.2 5.3 5.0 --- 263.8 8.79 53 4.8 523 .39 .44 .6 .6 .4 .1 .2 4.3 5.8 16 13 13 8.3 6.8 6.8 12 8.0 7.4 7.6 7.2 6.0 6.2 6.6 5.8 5.4 5.1 5.3 5.0 6.3 16 8.9 16 8.0 238.7 7.70 16 4.1 473 .35 .40 7.2 10 23 12 8.7 7.2 6.7 6.3 6.4 6.1 5.6 5.2 5.0 4.8 5.7 4.8 5.5 8.2 16 33 41 49 156 216 150 56 9.5 7.3 6.6 6.4 885.2 29.5 216 4.8 1760 1.32 1.48 5.6 5.4 4.8 4.5 4.3 4.8 5.0 4.9 6.5 8.0 6.4 5.1 6.5 5.9 6.3 7.1 7.8 8.8 8.2 40 171 95 35 23 11 18 13 72 24 76 21 714.9 23.1 171 4.3 1420 1.03 1.19 14 10 14 14 10 7.6 6.3 6.3 69.3 632 612 ell 620 613 68.0 632 613 670 618 elO 646 6440 646 6650 670 e!6 ell 619 e!4 67.0 638 1687.5 54.4 650 6.3 3350 2.44 2.82 e!3 e!2 e8.5 67.5 67.3 6.7 6.2 6.1 7.1 5.7 5.0 6.1 6.9 8.3 27 9.5 6.3 8.0 5.8 4.7 7.9 11 18 8.0 5.8 308 39 14 18 46 643.4 21.4 308 4.7 1280 .96 1.07 , BY WATER YEAR (WY) 8.62 11.0 1993 5.29 1995 FOR 1997 9979 27 650 4 4 3570 15 19790 1 16 46 13 5 26.7 123 1992 4.83 1990 WATER YEAR .3 .3 Aug 24 .1 May 4 .5 Apr 30 Nov 12 .79 Nov 12 .23 .65 .6 48.9 117 1992 14.7 1991 48.9 147 1993 6.74 1994 WATER 40. 52. 22. 4040 1. 1. 19100 24. 29200 1. 24. 69 11 4. 35.8 54.4 1997 10.2 1993 YEARS 1990 3 3 0 Sep 1 Oct 4 Oct Sep 12 Sep 81 55 4 77.1 189 1996 21.4 1997 - 1997 1992 1994 10 1996 27 1992 22 1992 10 1996 10 1996 e Estimated 266 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water year 1990 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: March 1990 to current year. INSTRUMENTATION.—USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,490 mg/L September 10, 1996; Minimum daily mean, 2 mg/L May 5,1997. SEDIMENT LOADS: Maximum daily mean, 17,900 tons (16,200 tonnes) September 10, 1996; Minimum daily mean, 0.05 ton (0.3 tonne) several days. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 775 mg/L November 07, 1996; Minimum daily mean, 2 mg/L May 5, 1997. SEDIMENT LOADS: Maximum daily mean, 1,880 tons (1,710 tonnes) January 22, 1997; Minimum daily mean, 0.90 ton (0.82 tonne) May 5, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 20 18 17 22 21 17 25 21 22 41 31 19 17 16 15 15 14 13 13 13 12 12 12 12 20 49 32 37 51 19 15 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 20 18 17 22 21 17 25 21 22 41 31 19 17 16 15 15 14 13 13 13 12 12 12 12 20 49 32 37 51 19 15 88 85 83 91 105 109 110 111 112 117 98 58 47 45 43 42 40 42 86 172 247 313 238 167 126 141 74 107 135 59 35 137 144 149 148 157 85 125 45 35 27 17 9.1 13 17 47 63 40 58 35 72 376 425 368 219 163 65 50 23 38 85 52 28 51 22 19 19 30 414 46 40 26 132 506 231 43 30 32 47 45 70 43 40 57 39 60 34 21 18 19 18 39 47 92 41 34 35 58 775 91 72 54 251 640 436 83 51 57 89 87 125 91 72 103 74 122 61 39 33 33 33 69 75 37 16 29 14 39 720 91 38 40 208 423 476 77 27 48 39 158 287 202 92 181 116 76 73 45 37 17 28 35 MEAN DISCHARGE (CFS) DI 31 27 22 20 19 18 17 17 16 16 38 27 18 16 15 16 16 15 14 14 14 14 14 13 15 14 15 16 29 46 27 MEAN CONCEN- TRATION (MG/L) SCEMBER 60 45 41 38 35 34 33 32 31 30 67 49 36 30 28 27 27 26 26 25 25 25 26 26 26 26 27 28 52 83 51 SEDIMENT DISCHARGE (TONS/DAY) 73 64 40 21 41 37 50 25 40 40 75 28 11 29 28 37 23 16 14 13 14 14 19 18 11 31 31 14 21 84 31 TOTAL 661 3287.1 2219 3744 609 993 RIO ORANDE DE LOIZA BASIN 50055750 RIO ODRABO BELOW EL MANGO, PR—Continued 267 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) DISCHARGE (CTS) MEAN ___ CONCEN • 8EPIJUBNT TRATION DISCHARGE (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL 17 15 14 13 12 12 12 13 14 12 12 11 10 10 9.8 9.5 9.1 8.8 8.8 13 23 •105 •32 •33 •20 •12 •9.7 •19 •15 •8.4 •8.6 521.7 JANUARY 31 26 25 23 22 21 20 24 26 22 21 20 19 18 17 17 16 16 17 24 41 205 58 58 37 21 19 37 24 20 16 12 11 11 23 12 11 8.4 17 8.8 5.2 18 7.0 11 22 19 15 14 10 11 17 101 •1880 •163 •106 •67 •29 •28 •53 •29 •23 •19 2761.4 •270 •210 •56 •16 •21 •52 •39 •24 •28 •25 •20 •21 •68 •40 •26 •18 •21 •17 •17 •14 •21 •23 •47 •17 •26 •28 •13 11 FEBRUARY 299 306 58 31 35 71 56 42 39 37 36 36 83 58 44 39 35 31 28 26 31 37 56 24 16 10 9 8 •113 •174 •41 •28 •36 •68 •38 •22 •19 •39 •37 •40 •78 •50 •21 •31 •22 •18 •19 •22 •31 •30 •27 •17 elO 1189 •9.6 •8.5 7.1 1056.2 i TO SEVTEM MEAN DISCHARGE (CFS) 11 11 15 19 17 13 12 12 13 11 10 11 11 10 10 12 12 11 11 9.9 9.5 9.6 9.1 8.8 8.6 8.6 8.0 8.5 13 11 9.5 BER 1997 MEAN CONCEN- TRATION (MG/L) MARCH 8 8 17 69 36 16 11 24 25 7 8 14 8 8 12 15 11 7 7 8 10 11 10 12 16 21 19 16 19 26 24 SEDIMENT DISCHARGE (TONS/DAY) 2.8 2.0 13 60 26 11 11 8.3 5.7 4.5 7.9 11 6.7 7.4 7.5 13 9.2 4.8 5.6 5.8 5.3 2.9 6.2 8.7 13 19 18 7.8 7.6 14 17 346.1 342.7 e Eitinated 268 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGEE TRATION DISCHARGE DAY (CFS) (M6/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.5 53 39 10 8.0 7.8 6.9 6.7 6.5 6.3 6.0 6.1 6.2 6.1 6.1 5.8 5.8 5.8 5.7 5.7 5.6 5.5 4.9 4.8 4.8 4.9 4.8 5.2 5.3 5.0 APRIL 25 99 111 27 13 11 11 10 9 8 7 8 10 14 21 15 8 7 10 14 18 17 16 18 22 22 20 12 6 5 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MAY 17 68 37 20 7.6 4.1 2.0 6.3 7.1 7.4 6.6 3.0 1.9 2.4 12 13 6.7 7.4 3.6 3.3 6.6 6.3 14 15 10 4.0 19 8.0 3.3 4.2 —— .6 .6 .4 .1 .2 4.3 5.8 16 13 13 8.3 6.8 6.8 12 8.0 7.4 7.6 7.2 6.0 6.2 6.6 5.8 5.4 5.1 5.3 5.0 6.3 16 8.9 16 8.0 6 5 4 3 2 4 8 28 23 25 11 9 8 17 11 10 10 9 8 10 11 10 10 9 9 9 11 35 16 29 13 4.5 4.2 2.3 1.2 .90 2.3 5.5 16 6.9 18 6.2 6.0 7.4 8.6 9.3 6.8 2.7 6.2 6.9 4.1 2.8 2.1 3.4 4.2 4.4 6.5 7.5 7.2 6.1 8.9 2.2 7.2 10 23 12 8.7 7.2 6.7 6.3 6.4 6.1 5.6 5.2 5.0 4.8 5.7 4.8 5.5 8.2 16 33 41 49 156 216 150 56 9.5 7.3 6.6 6.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 21 37 42 25 32 48 30 15 18 24 17 11 11 12 12 13 13 12 27 40 26 45 289 168 36 24 28 34 29 24 2.0 3.4 11 21 24 35 14 2.9 6.6 3.3 7.1 2.3 1.2 1.1 1.0 1.6 2.6 2.0 2.4 3.5 2.0 6.4 174 41 3.7 2.4 2.3 2.8 2.6 2.4 263.8 326.8 238.7 181.30 885.2 387.6 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 269 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 5.6 5.4 4.8 4.5 4.3 4.8 5.0 4.9 6.5 8.0 6.4 5.1 6.5 5.9 6.3 7.1 7.8 8.8 8.2 40 171 95 35 23 11 18 13 72 24 76 21 JULY 20 17 18 20 23 26 32 38 29 21 20 19 20 21 18 15 17 39 16 75 147 171 116 97 39 34 27 113 37 147 40 TOTAL 714.9 —— YEAR e 9979.3 Estimated MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 10 12 9.3 3.8 2.5 2.6 3.1 7.7 5.8 2.1 4.4 2.9 2.0 2.0 5.9 2.9 2.5 8.5 4.4 13 41 51 25 35 12 3.9 2.8 54 29 76 28 465.1 14997.70 14 10 14 14 10 7.6 6.3 6.3 e9.3 e32 e!2 ell e20 e!3 e8.0 e32 e!3 e70 e!8 elO e46 e440 e46 e650 e70 e!6 ell e!9 e!4 e7.0 e38 1687.5 43 28 25 23 22 21 29 43 47 45 24 218 29 55 57 48 54 27 12 23 49 206 76 360 130 43 13 13 15 14 207 —— 26 9.1 6.6 2.6 2.2 3.7 6.0 11 e8.8 e8.5 e4.2 e!54 elS eSO e90 e36 e34 elS eS.S e22 e!7 e!67 eSl e88 e90 e24 elO ell e6.0 e3.8 e26 1004.0 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER e!3 e!2 e8.5 e7.5 e7.3 6.7 6.2 6.1 7.1 5.7 5.0 6.1 6.9 8.3 27 9.5 6.3 8.0 5.8 4.7 7.9 11 18 8.0 5.8 308 39 14 18 46—— 643.4 22 98 27 32 22 15 14 14 18 24 21 18 14 20 50 16 13 15 16 22 30 21 36 30 30 473 73 37 36 77 —— —— e4.9 e74 e35 e29 e!4 9.7 3.8 10 17 14 12 5.2 2.5 2.6 6.5 6.6 3.2 3.7 3.7 2.8 6.7 2.3 3.7 5.3 3.8 47 9.5 12 48 50—— 448.5 270 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DATE NOV 1996 07... AUO 1997 12... 31... SEP 02... TIME 0336 1470 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. PALL DIAM. % PINER THAN .002 MM (70326) SED* SUSP. PALL DIAM. * PINER THAN .004 MM (70327) SED. SUSP. PALL DIAM. * FINER THAN .008 MM (70328) 2215 1507 1651 ell e38 el2 5600 22200 1698 eSO 2560 e262 1810 e58 32 70 66 60 41 74 68 67 51 76 73 72 DATE NOV 1996 07... AUO 1997 12... 31... SEP 02... SED. SUSP. PALL DIAM. % PINBR THAN .016 MM (70329) 65 80 78 SED. SUSP. PALL DIAM. % PINER THAN .031 MM (70330) 78 86 84 86 SED. SUSP. SIEVE DIAM. % PINER THAN .062 MM (70331) 93 98 99 98 SED. SUSP. SIEVE DIAM. % PINER THAN .125 MM (70332) 98 99 100 99 SUSP. SIEVE DIAM. % PINER THAN .250 MM (70333) 99 100 100 100 SUSP. SIEVE DIAM. % PINER THAN .500 MM (70334) 100 100 100 100 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 100 e - estimate RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 271 DATE OCT 1996 24... NOV 07... 07... MAR 1997 20... JUN 30... JUL 24... TIME 1801 1245 1445 1830 1200 1200 DIS- CHARGE, XNST. CUBIC FEET PER SECOND (00061) 12 1234 361 9.6 6.3 56 SEDI- MENT, SUS- PENDED (MG/L) (80154) 2200 1270 1260 109 229 2010 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 71 4230 1230 2.8 3.9 304 SED. SUSP. SIEVE DIAM. «s FINER THAN .062 MM (70331) 14 94 99 98 76 99 272 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR LOCATION.—Lat 18°12'58", long 65°55'34", Hydrologic Unit 21010005, on left bank at Highway 919, 0.5 mi (0.8 km) upstream from Quebrada Don Victor, 1.7 mi (2.7 km) upstream from Rio Gurabo and 1.0 mi (1.6 km) south of Juncos. DRAINAGE AREA.—16.4 mi* (42.5 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—January 1971 to current year. GAGE.—Water-stage recorder. Elevation of gage is 320 ft (98 m), from topographic map. REMARKS.—Records poor. Minor diversion from public water supply tank, 0.5 mi upstream, during low flow. Gage-height and precipitation satellite telemetry at station. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate discharges (no stages were recorded) of major floods are as follows: Sept. 6, 1960, 37,100 ftVs (1,050 m'/S), Oct. 9, 1970, 18,200 ftVs (515 mVs) . DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR MAY JUN JUL 1 38 e34 2 38 e68 3 36 e30 4 34 e25 5 37 e25 6 31 ellO 7 44 308 8 32 68 9 e34 49 10 e65 49 11 e44 161 12 e25 543 13 e23 203 14 e22 65 15 e20 58 16 e20 40 17 e!9 59 18 e!7 54 19 e!7 311 20 e!7 91 21 e!6 97 22 e!6 60 23 e!6 52 24 e!6 51 25 e30 36 26 e65 29 27 e42 24 28 e50 28 29 e68 29 30 e25 32 31 e20 TOTAL 977 2789 MEAN 31.5 93.0 MAX 68 543 MIN 16 24 AC-FT 1940 5530 CFSM 1.92 5.67 IN. 2.22 6.33 STATISTICS OF MONTHLY MEAN MEAN 71.6 87.1 MAX 293 461 (WY) 1986 1988 MIN 19.9 16.8 (WY) 1993 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 24 22 18 18 17 16 27 16 15 14 e!6 e!2 12 12 11 13 17 16 16 16 15 14 14 13 31 13 13 13 21 63 37 575 18.5 63 11 1140 1.13 1.30 16 14 13 12 13 11 10 10 10 10 e!9 9.6 8.8 8.9 8.8 8.2 7.6 7.5 7.8 13 21 128 17 26 12 12 9.8 15 8.8 6.7 6.9 481.4 15.5 128 6.7 955 .95 1.09 DATA FOR WATER 52.8 550 1988 11.0 1990 FOR 24.6 77.0 1992 11.4 1976 217 174 46 23 27 43 32 19 23 20 16 17 55 32 22 15 17 14 14 11 17 19 38 14 21 22 e!7 e9.0 —— 994.0 35.5 217 9.0 1970 2.16 2.25 YEARS 1971 19.5 47.9 1984 7.21 1974 e9.0 e9.0 e!3 e!6 e!4 ell 69.8 12 9.0 8.3 8.4 8.9 8.9 8.1 7.9 17 11 9.7 10 8.6 7.9 7.6 7.5 7.7 7.3 7.6 8.5 8.1 17 12 9.7 310.5 10.0 17 7.3 616 .61 .70 - 1997 18.5 39.7 1973 7.01 1977 1996 CALENDAR YEAR 24930. 68. 5000 4. 5. 49450 4. 56. 116 27 11 9 1 Sep 10 1 May 28 5 May 22 15 55 9.2 271 90 24 18 15 15 14 13 13 11 12 10 10 8.5 7.8 8.1 7.7 7.1 7.0 7.6 7.6 5.8 5.7 5.8 5.5 5.6 6.6 6.3 6.1 —— 634.0 21.1 271 5.5 1260 1.29 1.44 5.1 5.1 4.4 5.2 5.8 4.6 4.8 5.5 15 33 39 24 18 13 27 20 14 9.3 7.8 7.3 12 7.4 7.0 6.5 6.7 6.4 29 37 24 16 26 445.9 14.4 39 4.4 884 .88 1.01 20 25 37 20 15 11 8.4 8.0 8.0 6.9 8.3 6.1 9.9 5.6 5.0 4.4 4.3 3.9 8.2 7.9 4.9 4.4 50 48 12 11 7.8 5.8 5.0 4.8 —— 376.6 12.6 50 3.9 747 .77 .85 4.9 4.7 4.0 4.0 4.9 20 6.7 5.4 7.4 5.8 5.0 4.8 16 7.9 7.1 9.1 12 24 15 25 498 160 26 60 17 12 19 100 23 68 18 1194.7 38.5 498 4.0 2370 2.35 2.71 17 12 14 11 9.3 8.7 7.7 10 12 40 15 14 26 16 10 41 17 87 22 12 e62 6900 57 795 125 34 23 40 31 15 81 2564.7 82.7 900 7.7 5090 5.04 5.82 27 26 19 14 12 10 11 69 26 12 11 24 15 39 72 20 15 17 12 10 44 25 37 69 19 146 34 18 16 62 ___ 931 31.0 146 10 1850 1.89 2.11 , BY WATER YEAR (WY) 15.2 41.7 1985 5.17 1995 FOR 1997 12273 33 900 3 4 6290 12 24350 2 27 60 15 6 47.3 268 1985 5.02 1990 WATER YEAR .8 .6 Aug 22 .9 JUn 18 .6 Jun 29 Aug 24 .37 Aug 24 .05 .84 .5 51.6 188 1979 4.95 1994 47.8 163 1981 4.61 1994 WATER 48 121 17 9100 1 1 40000 25 35230 2 40 71 18 6 61.7 231 1979 4.71 1994 YEARS 1971 - .6 .1 Dec 8 .4 JUl 15 .7 JUl 10 Dec 8 .63 Dec 8 .97 .29 .9 83.6 255 1979 10.8 1987 1997 1988 1990 1987 1994 1994 1987 1987 e Estimated 273 RIO GRANDE DE LOZZA BASIN 50056400 RZO VALENCZANO NEAR JUNCOS, PR—Continued WATER-QUALITY RECORDS PERZOD OF RECORDS.— Water years 1983 to 1986 and water year 1989 to current year. PERZOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October 1994 to current year. INSTRUMENTATION.— Automatic sediment sampler since 1984. REMARKS:— Sediment samples ware collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERZOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 8,340 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 263,000 tons (238,000 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) several days. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,300 mg/L February 1, 1997; Minimum daily mean, 5 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 6,930 tons (6,290 tonnes) August 24, 1997; Minimum daily mean, 0.06 tons (0.05 tonne) May 3, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 38 38 36 34 37 31 44 32 e34 e65 e44 e25 e23 e22 e20 e20 e!9 e!7 e!7 e!7 e!6 e!6 e!6 e!6 e30 e65 e42 eSO e68 e25 e20 36 36 35 32 56 37 152 157 72 24 18 18 18 17 18 21 24 28 33 39 45 53 62 72 109 222 58 134 286 98 34 3.7 3.6 3.5 3.0 6.1 3.1 21 13 e9.5 e4.2 e2.1 el. 6 el. 2 el.l el.O el.l el. 2 el. 3 el. 5 el. 8 el. 9 e2.3 e2.7 e3.1 e6.8 e39 e8.7 e!7 e46 e!4 el. 8 NOVEMBER e34 e68 e30 e25 e25 ellO 308 68 49 49 161 543 203 65 58 40 59 54 311 91 97 60 52 51 36 29 24 28 29 32 —— 48 170 225 140 128 488 1120 722 214 160 649 1040 664 307 304 179 272 142 896 480 425 170 39 131 145 76 74 118 131 103 —— e3.5 e25 e30 elO e8.6 e393 1560 137 29 25 386 2810 464 55 50 20 57 22 978 127 126 29 5.6 22 14 5.9 4.8 9.4 11 11—— DECEMBER 24 22 18 18 17 16 27 16 15 14 e!6 e!2 12 12 11 13 17 16 16 16 15 14 14 13 31 13 13 13 21 63 37 120 98 93 89 84 80 139 77 70 63 58 53 48 44 40 35 20 14 28 58 95 78 59 44 111 70 74 78 104 1230 192 7.8 5.8 4.7 4.2 3.9 3.5 12 3.4 2.8 2.4 e2.5 el. 9 1.6 1.4 1.2 1.3 .89 .61 1.2 2.5 3.9 3.0 2.2 1.6 11 2.5 2.6 2.9 6.6 290 26 TOTAL 977 227.9 2789 7428.8 575 417.90 e Estimated 274 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MO/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 16 14 13 12 13 11 10 10 10 10 •19 9.6 8.8 8.9 8.8 8.2 7.6 7.5 7.8 13 21 128 17 26 12 12 9.8 15 8.8 6.7 6.9 67 28 15 14 27 17 15 14 13 12 83 55 42 28 24 42 59 41 28 19 81 612 131 126 63 55 47 69 46 37 37 2.9 1.1 .53 .47 .93 .52 .41 .38 .35 .33 •4.4 1.4 1.0 .67 .56 .92 1.2 .83 .58 .65 8.4 410 6.3 12 2.1 1.7 1.3 3.2 1.1 .67 .68 (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CrS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) FEBRUARY 217 174 46 23 27 43 32 19 23 20 16 17 55 32 22 15 17 14 14 11 17 19 38 14 21 22 •17 •9.0 ... —— 1300 598 220 125 114 233 184 267 110 82 68 97 250 160 103 74 89 90 76 53 85 96 218 90 110 96 93 28 ... —— 2010 577 29 7.9 18 44 21 14 7.2 4.4 2.9 5.6 42 14 6.3 3.0 4.2 3.4 3.0 1.6 4.5 5.2 32 3.6 7.2 6.7 6.1 .68 —— MARCH •9.0 •9.0 •13 •16 •14 •11 •9.8 12 9.0 8.3 8.4 8.9 8.9 8.1 7.9 17 11 9.7 10 8.6 7.9 7.6 7.5 7.7 7.3 7.6 8.5 8.1 17 12 9.7 10 9 10 13 17 17 17 48 43 30 21 17 15 17 18 58 16 12 12 11 11 10 10 9 9 11 13 13 62 58 27 .25 .23 .29 .51 .67 .48 .42 1.8 1.1 .68 .47 .40 .37 .36 .38 3.6 .47 .32 .32 .26 .23 .21 .20 .19 .19 .23 .30 .28 4.9 1.9 .70 TOTAL 481.4 467.58 994.0 2884.48 310.5 22.71 • Estimated RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 275 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 ^ 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.2 271 90 24 18 15 15 14 13 13 11 12 10 10 8.5 7.8 8.1 7.7 7.1 7.0 7.6 7.6 5.8 5.7 5.8 5.5 5.6 6.6 6.3 6.1 APRIL 15 353 85 15 14 13 13 12 9 8 7 7 9 12 11 10 40 45 38 31 26 23 18 10 7 8 11 11 7 5 .36 1360 56 .99 .69 .54 .50 .44 .34 .27 .21 .22 .25 .33 .25 .21 .91 .94 .72 .60 .54 .47 .28 .16 .10 .12 .16 .20 .12 .08 —— MEAN DISCHARGE (CFS) 5.1 5.1 4.4 5.2 5.8 4.6 4.8 5.5 15 33 39 24 18 13 27 20 14 9.3 7.8 7.3 12 7.4 7.0 6.5 6.7 6.4 29 37 24 16 26 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 5.1 5.1 4.4 5.2 5.8 4.6 4.8 5.5 15 33 39 24 18 13 27 20 14 9.3 7.8 7.3 12 7.4 7.0 6.5 6.7 6.4 29 37 24 16 26 5 5 5 20 15 13 13 13 62 163 184 127 117 72 71 55 31 34 52 43 37 15 9 9 10 10 154 308 106 84 125 .07 .07 .06 .35 .24 .16 .17 .19 3.9 18 34 9.3 6.2 2.8 6.0 3.3 1.2 .85 1.1 .88 1.3 .30 .17 .16 .17 .17 83 64 9.2 3.8 14 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 20 25 37 20 15 11 8.4 8.0 8.0 6.9 8.3 6.1 9.9 5.6 5.0 4.4 4.3 3.9 8.2 7.9 4.9 4.4 50 48 12 11 7.8 5.8 5.0 4.8 104 175 101 94 54 70 54 36 27 21 36 31 48 24 13 7 6 7 28 36 25 21 375 213 40 18 15 13 11 9 7.2 13 11 5.5 2.4 2.0 1.2 .79 .58 .40 .95 .52 1.4 .37 .17 .09 .08 .07 .86 .77 .33 .24 142 39 1.3 .53 .31 .20 .14 .12 TOTAL 634.0 1427.00 445.9 265.11 376.6 233.52 276 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) .9 .7 .0 .0 .9 20 6.7 5.4 7.4 5.8 5.0 4.8 16 7.9 7.1 9.1 12 24 15 25 498 160 26 60 17 12 19 100 23 68 18 JULY 8 8 8 8 21 88 50 32 38 33 28 23 78 29 24 22 21 259 313 97 1140 329 93 223 51 42 89 346 123 284 91 TOTAL 1194.7 —— YEAR e 12273.8 Estimated MEAN DISCHARGE (CPS) MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) AUGUST .11 .10 .09 .09 .29 6.5 .93 .46 .83 .51 .38 .30 4.3 .63 .46 .54 .68 36 13 9.2 5020 236 6.8 62 2.4 1.4 5.0 182 8.5 78 4.4 5681.90 28585.81 17 12 14 11 9.3 8.7 7.7 10 12 40 15 14 26 16 10 41 17 87 22 12 e62 e900 57 795 125 34 23 40 31 15 81 2564.7 98 59 74 39 23 20 18 44 61 200 54 34 137 109 109 232 111 295 69 48 61 630 339 1030 414 90 96 126 211 303 392 —— 4.8 1.8 3.0 1.2 .58 .47 .38 1.2 2.1 26 2.3 3.6 14 5.4 3.0 44 5.8 93 4.1 1.5 e6.4 e937 58 6930 188 8.1 5.9 21 23 12 111 8518.63 SEPTEMBER 27 26 19 14 12 10 11 69 26 12 11 24 15 39 72 20 15 17 12 10 44 25 37 69 19 146 34 18 16 62 —— 931 105 95 106 36 11 8 8 360 131 17 15 105 92 198 220 17 15 103 138 86 281 140 139 298 105 372 158 54 43 261 —— —— 8.6 12 5.7 1.3 .33 .22 .23 307 12 .54 .43 13 4.2 33 64 .94 .59 5.3 4.5 2.3 51 10 17 77 5.6 281 16 2.7 1.8 72—— 1010.28 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 277 DATE NOV 1996 07... 12... 19... DEC 30... JAN 1997 22... FEB 01... MAY 27... JUL 21... 30... AUG 22... SEP 26... TIME 1400 1600 0545 0630 0710 1215 2245 1145 0734 1900 1325 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1270 195 658 39 284 1170 231 405 95 331 370 SEDI- MENT, SUS- PENDED (MG/L) (80154) 4510 2570 1850 6600 2270 9020 2200 1530 917 1490 928 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 15500 1350 3280 695 1740 28500 1370 1670 235 1330 927 SED. SUSP. FALL DIAM. «6 FINER THAN .002 MM (70326) 27 47 51 49 39 27 68 69 79 53 73 SED. SUSP. FALL DIAM. «6 FINER THAN .004 MM (70327) 42 52 55 57 46 33 74 76 85 62 81 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 58 78 66 67 59 39 82 80 88 71 86 DATE NOV 1996 07... 12... 19... DEC 30... JAN 1997 22... FEB 01... MAY 27... JUL 21... 30... AUG 22... SEP 26... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 65 79 77 79 68 50 88 88 91 82 89 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 74 88 83 86 76 64 90 89 93 85 93 SED. SUSP. SIEVE DIAM. 96 FINER THAN .062 MM (70331) 86 99 94 99 89 83 99 99 99 96 99 SED. SUSP. SIEVE DIAM. 96 FINER THAN .125 MM (70332) 96 100 98 100 96 93 99 99 99 98 100 SED. SUSP. SIEVE DIAM. «6 FINER THAN .250 MM (70333) 98 100 99 100 99 98 100 100 100 99 100 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 100 100 100 100 100 100 100 100 100 100 SED. SUSP. SIEVE DIAM. 96 FINER THAN 1.00 MM (70335) 100 100 100 100 100 100 100 100 100 100 100 278 RIO ORANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JTJNCOS, PR—Continued DATE NOV 1996 06... 11... 13... 13... 19... DEC 21... JAN 1997 22... 22... FEB 08... •TON 02... JUL 19... 24... AUG 30... SEP 08... 21... ni OATf ,T AND TIME 1700 0100 0545 0815 0230 0740 0610 0730 1720 0745 0715 1145 1548 2030 1740 L, WATER YEAR OCTOBER 1995 TO SEPTEMBER CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, INST. CUBIC FEET PER SECOND (00061) 678 278 367 387 492 15 161 434 18 19 13 220 14 218 61 SEDI- MENT, SUS- PENDED (MO/L) (80154) 1970 646 3860 1080 1290 105 1820 2820 291 232 524 658 313 1030 1050 MENT, DIS- CHARGE, SUS- PENDBD (T/DAY) (80155) 3610 485 3830 1130 1710 4.3 791 3300 14 12 18 391 12 606 173 SUSP. SIEVE DXAM. * FINER THAN .062 MM (70331) 91 96 94 95 92 97 94 94 98 99 99 93 99 95 99 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR 279 LOCATION.—Lat 18°15'30", long 65°58'05", Hydrologic Unit 21010005, on left bank, at bridge on Highway 181, 0.3 mi (0.5 km) east of Gurabo, and 4.5 mi (7.6 km) upstream from Rio Grande de Loiza. DRAINAGE AREA.--60.2 mi* (155.9 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--1958 (occasional low-flow measurements only), January to September 1959 (monthly measurements only), October 1959 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 131.58 ft (40.106 m) above mean sea level. Prior to Oct. 1, 1989 datum 5.0 ft (1.5 m) higher. REMARKS.--Records fair. Gage-height and precipitation satellite telemetry at station. Low flow affected by diversions for water supply about, 400 ft (121 m) upstream from station by PRASA. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN AUG SEP 1 78 74 2 73 135 3 68 66 4 74 54 5 72 46 6 63 134 7 81 804 8 76 167 9 93 101 10 153 82 11 113 344 12 71 1390 13 60 654 14 56 148 15 53 93 16 50 82 17 45 109 18 43 147 19 40 332 20 40 158 21 36 139 22 89 379 23 48 179 24 38 154 25 33 120 26 107 67 27 104 53 28 94 60 29 165 62 30 67 77 31 47 —— TOTAL 2230 6410 MEAN 71.9 214 MAX 165 1390 MXN 33 46 AC-FT 4420 12710 CFSM 1.19 3.55 IN. 1.38 3.96 STATISTICS OF MONTHLY MEAN MEAN 212 211 MAX 1414 1045 (WY) 1971 1988 MIN 16 . 0 23 . 7 (WY) 1968 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 88 67 50 44 41 35 41 33 29 28 83 62 34 28 26 29 28 25 24 22 24 24 23 23 33 27 24 37 48 132 83 1295 41.8 132 22 2570 .69 .80 46 34 32 26 24 26 22 25 29 24 32 22 21 19 20 19 19 17 17 30 64 365 94 100 77 31 22 24 43 25 20 1369 44.2 365 17 2720 .73 .85 613 208 99 39 48 68 64 65 54 62 50 50 91 67 60 47 44 43 42 45 48 57 52 37 35 37 36 25 ___ ___ —— 2186 78.1 613 25 4340 1.30 1.35 DATA FOR WATER YEARS 1960 148 863 1988 10.7 1968 FOR 61.5 204 1992 16.4 1968 47.2 131 1989 12.6 1968 26 24 28 35 31 30 24 24 26 24 22 21 22 22 21 22 26 24 25 21 20 19 18 17 17 17 17 16 18 30 22 709 22.9 35 16 1410 .38 .44 - 1997 38.6 97.5 1985 11.2 1965 1996 CALENDAR YEAR 64679.7 177 26200 3.7 5.2 128300 2.94 39.97 210 36 11 Sep 10 May 27 May 25 19 65 224 32 22 18 16 15 14 14 14 13 13 12 11 11 11 11 11 11 10 11 11 9.6 9.6 9.1 10 11 11 11—— 660.3 22.0 224 9.1 1310 .37 .41 10 9.7 9.7 9.8 10 10 9.9 16 20 31 29 24 16 20 24 21 22 18 15 13 16 13 12 11 11 12 12 43 21 26 20 535.1 17.3 43 9.7 1060 .29 .33 23 22 38 28 24 18 17 15 14 14 15 16 15 15 13 14 12 11 12 17 17 13 25 126 37 23 22 18 15 14 —— 663 22.1 126 11 1320 .37 .41 13 12 11 11 11 13 21 14 18 20 18 15 17 23 18 18 24 21 32 33 315 377 55 59 34 25 28 106 55 95 39 1551 50.0 377 11 3080 .83 .96 27 20 24 21 21 16 14 13 21 183 72 59 230 80 43 39 52 105 46 28 22 905 170 782 302 62 44 44 33 27 73 3578 115 905 13 7100 1.92 2.21 51 55 48 24 20 18 17 25 35 15 12 17 23 25 64 31 18 19 16 13 19 32 44 43 22 401 78 32 23 79 —— 1319 44.0 401 12 2620 .73 .82 , BY WATER YEAR (WY) 41.3 108 1978 13.1 1995 FOR 1997 22505 61 1390 9 9 6290 17 44640 1 13 106 27 12 141 746 1985 12.7 1990 WATER YEAR .4 .7 Nov 12 .1 Apr 26 .9 May 1 Nov 12 .42 Nov 12 .02 .91 130 468 1970 16.8 1972 114 376 1993 20.7 1994 WATER 129 286 42. 26200 3. 5. 62100 31. 93230 2. 29. 202 47 16 163 610 1979 24.8 1967 YEARS 1960 - 2 Sep 10 7 May 27 2 May 25 Sep 10 44 Sep 10 14 04 235 1225 1960 8.76 1967 1997 1979 1967 1996 1996 1996 1996 1996 280 RIO GRANDB DE LOIZA BASIN 50057000 RIO OORABO AT OURABO—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.— Water years 1985 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October 1983 to current year. INSTRUMENTATION.— USDH-48 and USD-77 sediment sampler, since 1984. Automatic sediment sampler, since 1984. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 9,220 mg/L Nov 27, 1987; Minimum daily mean, 3 mg/L August 09, 1994. SEDIMENT LOADS: Maximum daily mean, 686,000 tons (622,340 tonnes) Nov 27, 1987; Minimum daily mean, 0.08 tons (0.07 tonne) August 09, 1994. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,090 mg/L January 22, 1997; minimum daily mean, 4 mg/L December 10, 1996. SEDIMENT LOADS: Maximum daily mean, 4,790 tons (4,350 tonnes) November 12, 1996; minimum daily 0.22 tons (0.20 tonne) April 16, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 78 73 68 74 72 63 81 76 93 153 113 71 60 56 53 50 45 43 40 40 36 89 48 38 33 107 104 94 165 67 47 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 78 73 68 74 72 63 81 76 93 153 113 71 60 56 53 50 45 43 40 40 36 89 48 38 33 107 104 94 165 67 47 42 34 12 9 10 12 12 10 15 35 102 88 80 55 35 23 20 18 15 12 11 125 289 162 79 94 88 79 144 85 47 8.8 6.6 2.1 1.9 2.0 2.1 2.6 2.0 3.8 15 32 17 13 8.3 5.1 3.1 2.4 2.1 1.6 1.3 1.1 51 38 17 7.1 29 25 23 67 16 6.1 74 135 66 54 46 134 804 167 101 82 344 1390 654 148 93 82 109 147 332 158 139 379 179 154 120 67 53 60 62 77 NOVEMBER 155 121 102 41 28 104 578 148 87 75 276 782 555 123 53 53 70 131 397 150 126 213 150 117 101 52 29 39 26 54 DECEMBER 28 47 19 6.0 3.5 54 1810 73 26 18 515 4790 1290 51 13 12 35 55 442 65 52 380 75 52 34 9.6 4.1 6.6 4.5 14 88 67 50 44 41 35 41 33 29 28 83 62 34 28 26 29 28 25 24 22 24 24 23 23 33 27 24 37 48 132 83 41 26 22 18 13 9 22 16 7 4 57 34 26 23 20 18 16 11 8 7 6 6 6 5 16 23 21 32 42 87 69 10 4.8 3.0 2.2 1.5 .87 2.7 1.5 .56 .31 16 5.9 2.4 1.7 1.4 1.4 1.2 .77 .51 .41 .40 .38 .35 .32 1.7 1.7 1.4 3.3 5.8 38 16 2230 413.1 6410 9984.3 1295 128.48 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 281 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CPS) 46 34 32 26 24 26 22 25 29 24 32 22 21 19 20 19 19 17 17 30 64 365 94 100 77 31 22 24 43 25 20 MEAN CONCEN- TRATION (MO/L) JANUARY 39 24 16 11 12 19 11 18 11 10 11 9 12 16 10 9 9 10 11 14 32 1090 84 77 62 30 19 20 36 17 18 SEDIMENT DISCHARGE (TONS/DAY) 4.9 2.2 1.3 .78 .80 1.4 .65 1.2 .86 .62 .96 .56 .74 .85 .54 .46 .45 .46 .54 1.2 7.2 2040 22 22 14 2.5 1.1 1.8 4.8 1.1 .98 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 613 208 99 39 48 68 64 65 54 62 50 50 91 67 60 47 44 43 42 45 48 57 52 37 35 37 36 25 343 180 133 33 35 58 68 74 76 65 21 17 22 31 41 54 59 30 14 10 16 48 37 31 23 23 13 9 1500 138 37 3.5 4.8 11 13 14 11 11 2.8 2.3 5.5 5.5 6.5 6.9 7.0 3.4 1.6 1.2 2.6 7.4 5.2 3.1 2.2 2.4 1.3 .64 MEAN DISCHARGE (CFS) 26 24 28 35 31 30 24 24 26 24 22 21 22 22 21 22 26 24 25 21 20 19 18 17 17 17 17 16 18 30 22 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 9 8 7 6 7 9 11 13 16 18 13 8 10 17 32 54 50 42 26 15 11 9 7 7 8 8 9 10 13 57 27 .60 .52 .53 .59 .59 .70 .68 .86 1.1 1.2 .74 .46 .61 .99 1.8 3.3 3.5 2.7 1.8 .84 .58 .44 .35 .34 .36 .39 .40 .42 .65 4.6 1.6 TOTAL 1369 2138.95 2186 1810.84 709 34.24 282 RIO GRANDB DE LOIZA BASIN 50057000 RIO GURABO AT GURABO—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 19 65 224 32 22 18 16 15 14 14 14 13 13 12 11 11 11 11 11 11 10 11 11 9.6 9.6 9.1 10 11 11 11 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) APRIL 20 47 359 167 108 69 44 27 16 9 14 26 41 20 8 7 9 14 24 37 25 14 12 12 12 13 17 12 13 13 —— MAY 1.0 92 320 15 6.5 3.3 1.8 1.1 .59 .35 .51 .88 1.4 .67 .23 .22 .26 .41 .71 1.1 .68 .40 .34 .31 .32 .31 .50 .36 .37 .37 10 9.7 9.7 9.8 10 10 9.9 16 20 31 29 24 16 20 24 21 22 18 15 13 16 13 12 11 11 12 12 43 21 26 20 13 16 19 24 34 48 38 28 19 25 22 21 17 16 17 20 14 10 10 9 13 10 9 9 9 11 13 34 18 22 18 .37 .41 .51 .63 .92 1.3 1.0 1.2 1.0 2.2 1.9 1.4 .77 .89 1.2 1.2 .83 .52 .38 .32 .55 .37 .28 .26 .28 .35 .40 4.6 1.1 1.6 .95 JUNE 23 22 38 28 24 18 17 15 14 14 15 16 15 15 13 14 12 11 12 17 17 13 25 126 37 23 22 18 15 14 40 21 21 26 28 27 24 22 22 24 34 50 51 46 42 41 46 49 29 15 17 25 38 209 148 69 82 47 21 15 2.5 1.3 2.2 2.0 1.8 1.4 1.1 .92 .84 .87 1.4 2.1 2.1 1.9 1.5 1.5 1.5 1.5 .89 .65 .75 .88 5.2 73 15 4.4 4.9 2.3 .87 .56 —— TOTAL 660.3 451.99 535.1 29.69 663 137.83 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 283 DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 13 12 11 11 11 13 21 14 18 20 18 15 17 23 18 18 24 21 32 33 315 377 55 59 34 25 28 106 55 95 39 1551 22505.4 13 12 11 11 11 13 21 14 18 20 18 15 17 23 18 18 24 21 32 33 315 377 55 59 34 25 28 106 55 95 39 13 12 13 12 11 12 17 14 12 11 10 10 13 19 11 11 27 19 27 30 234 144 53 51 45 39 30 83 50 108 97 .44 .41 .39 .37 .32 .46 .93 .50 .58 .60 .51 .41 .66 1.2 .54 .55 1.8 1.1 2.4 3.0 463 339 7.9 9.8 4.1 2.7 2.3 42 8.3 34 10 27 20 24 21 21 16 14 13 21 183 72 59 230 80 43 39 52 105 46 28 22 905 170 782 302 62 44 44 33 27 73 69 38 25 14 11 9 9 10 16 223 243 48 229 219 132 38 58 102 106 79 56 608 137 602 408 294 150 32 27 23 86 5.1 2.2 1.7 .81 .62 .41 .36 .36 1.4 141 54 39 162 47 16 4.7 8.6 37 13 5.9 3.4 3530 76 3290 456 48 18 3.9 2.6 1.7 29 51 55 48 24 20 18 17 25 35 15 12 17 23 25 64 31 18 19 16 13 19 32 44 43 22 401 78 32 23 79 129 64 125 26 19 16 14 23 110 71 31 20 19 21 57 62 52 29 15 13 17 23 37 39 20 496 184 29 19 64 20 22 19 1.6 1.0 .77 .65 4.3 11 2.8 1.0 1.1 1.2 1.6 11 5.3 2.6 1.5 .65 .46 1.0 2.1 4.8 5.2 1.2 1340 36 2.5 1.2 18 940.27 25590.98 3578 7999.76 1319 1521.53 284 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR—Continued MATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE NOV 1996 07... AUG 1997 22... 22... SEP 26... DATE NOV 1996 07... AUG 1997 22... 22... TIME 0655 1515 1705 1905 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 63 69 74 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 2120 2580 3170 375 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 73 80 81 SEDI- MENT, SUS- PENDED (MG/L) (80154) 4450 2860 2050 2560 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 87 91 92 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 25500 19900 17500 2590 SED. SUSP. SIEVE DIAM. 9g FINER THAN .125 MM (70332) 97 97 96 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 35 35 45 34 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 99 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 41 44 54 40 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 100 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 52 55 64 48 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 26... 60 69 83 95 99 99 100 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 285 DATE OCT 1996 22... JAN 1997 22... APR 03... JUN 18... AUG 22... 22... 24... SEP 26... 26... TIME 1737 1535 1600 1545 1725 1930 2045 1222 1530 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 589 340 77 12 3180 2240 3950 843 1190 SEDI- MENT, SUS- PENDED (MG/L) (80154) 443 2960 240 53 1600 887 1430 1010 1010 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 704 2720 50 1.7 13700 5360 15200 2300 3240 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 99 100 99 98 94 97 92 87 97 286 RIO GRANDE DE LOIZA BASIN 50057025 RIO GURABO NEAR GURABO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°15'56", long 65°59'04", at bridge on Highway 941, 1.2 mi (1.9 km) west-northwest from gaging station 50057000, and 1.0 mi (1.6 km) northwest of Gurabo plaza. DRAINAGE AREA.—62.8 mi 2 (162.7 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DZS- DEMAND, FORM, STREP - ZNST. CZFZC WHOLE SOLVED CHEM- FECAL, TOCOCCZ CUBIC CON- FZELD TEMPER- TUR- OXYGEN, (PER- ZCAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BZD- DZS- CENT (HZGH UM-MF (COLS. TZME PER ANCE ARD WATER ZTY SOLVED SATDR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATZON) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1300 E65 387 7.4 30.0 1.6 8.2 106 <10 3300 420 0800 E44 490 6.6 24.5 2.7 2.8 33 <10 41000 280 0830 29 323 6.5 27.0 12 3.8 48 12 2000 160 1105 E44 287 6.6 30.0 17 2.3 30 14 2900 510 ALKA- HARD- NESS TOTAL (MG/L AS CACO3) (00900) 130 — 92 83 FLUO- RZDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.15 0.15 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) — 0.82 0.80 0.84 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 32 — 21 20 SILICA, DZS- SOLVED (MG/L AS SZO2) (00955) 30 — 31 27 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.9 1.9 1.6 1.6 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 — 9.2 8.0 SOLZDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 244 — 192 174 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 0.73 8.6 7.3 6.9 SODIUM, DZS- SOLVED (MG/L AS NA) (00930) 30 — 25 20 SOLZDS, DZS- SOLVED (TONS PER DAY) (70302) E42.8 — 14.8 E20.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.230 0.200 0.200 0.520 SODIUM AD- SORP- TION RATZO (00931) 1 — 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 8 7 23 36 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.1 — 3.6 4.5 NZTRO- GEN, NZTRATE TOTAL (MG/L AS N) (00620) 1.10 1.10 0.730 0.660 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — LZNZTY WAT WH TOT FET FZELD MG/L AS CACO3 (00410) 140 160 100 98 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.040 0.060 0.120 0.062 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 — <10 — SULFZDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, N02+NO3 TOTAL (MG/L AS N) (00630) 1.10 1.10 0.850 0.720 CADMIUM WATER UNPLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 18 — 15 14 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.240 0.430 0.270 0.120 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 33 — 27 21 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.49 0.40 0.53 0.72 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — DATE OCT 1996 09... FEB 1997 20... MAY 16... AUG 28... DATE OCT 1996 09... FEB 1997 20... MAY 16... AUG 28... DATE OCT 1996 09... FEB 1997 20... MAY 16... AUG 28... K - non-ideal count E - Estimated near station 50057000 RIO GRANDE DE LOIZA BASIN 50057025 RIO GURABO NEAR GURABO, PR—Continued MATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 287 DATE OCT 1996 09... FEB 1997 20... MAY 16... AUO 28... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (U6/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 370 220 <1 <1 350 190 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 0.02 <0.01 288 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR LOCATION.--Lat 18°17'41", Ion? 66°02'44", Hydrologic Unit 21010005, at right bank, off road 798, upstream side of bridge on Highway 52, 0.5 mi (0.8 km ) northeast from Escuela Segunda Unidad de Francisco Valdes, and 0.8 mi (1.3 km) north of La Barra. DRAINAGE AREA.--7.53 mi 2 (19.50 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—March 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 164 ft (50 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC APR MAY JUN JUL SEP 1 20 11 2 18 8.6 3 9.5 13 4 9.1 9.5 5 8.8 11 6 8.7 9.2 7 8.6 13 8 8.3 8.9 9 8.2 7.6 10 8.1 11 11 8.2 19 12 9.6 38 13 8.6 29 14 7.9 12 15 7.4 9.4 16 7.4 8.4 17 7.3 18 18 7.3 9.2 19 7.4 7.4 20 7.4 6.9 21 7.3 18 22 7.2 65 23 7.0 17 24 6.7 15 25 6.7 11 26 24 9.2 27 9.4 11 28 46 10 29 11 10 30 9.7 21 31 9.5 TOTAL 330.3 447.3 MEAN 10.7 14.9 MAX 46 65 MIN 6.7 6.9 AC-FT 655 887 CFSM 1.41 1.98 IN. 1.63 2.21 15 13 11 11 10 9.4 8.8 8.4 8.3 8.4 10 8.7 8.4 8.0 8.0 8.4 8.1 8.0 7.8 7.8 8.0 7.6 7.7 8.6 8.7 38 14 18 30 19 14 360.1 11.6 38 7.6 714 1.54 1.78 STATISTICS OF MONTHLY MEAN DATA MEAN 15.1 14.0 MAX 39.4 36.2 (WY) 1991 1993 MIN 4.60 7.18 (WY) 1992 1991 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 11.7 29.9 1993 5.55 1994 13 18 12 12 12 10 10 9.8 9.3 8.5 8.7 8.7 8.8 8.5 8.3 8.6 8.6 9.0 9.0 8.9 49 42 27 41 21 14 12 12 12 11 10 452.7 14.6 49 8.3 898 1.94 2.24 30 16 11 e!2 e!3 e!2 e!3 e9.4 e!4 e9.0 e9.4 9.5 9.8 10 9.0 8.6 8.5 9.0 9.2 9.4 14 10 8.9 8.8 8.9 8.7 8.4 8.3 ___ ___ 307.8 11.0 30 8.3 611 1.46 1.52 FOR WATER YEARS 1990 11.7 24.5 1992 4.48 1994 9.96 18.8 1995 4.29 1994 8.2 8.5 11 8.9 11 8.5 8.8 9.2 8.7 7.6 7.3 7.7 7.7 7.6 7.7 7.7 7.3 8.1 7.1 6.8 6.8 6.9 7.0 7.3 7.3 7.7 7.8 10 7.5 6.9 6.4 247.0 7.97 11 6.4 490 1.06 1.22 - 1997 5.26 7.97 1997 2.48 1994 FOR 1996 CALENDAR YEAR 6450.7 17.6 1670 2.1 3.3 12790 2.34 31.87 24 7.4 3.7 Sep 10 Apr 19 Mar 27 6.3 7.0 6.9 6.2 5.8 5.5 5.2 5.1 5.0 4.9 .6 .6 .6 .4 .5 .4 .3 .3 .2 .2 .2 .1 .0 3.9 3.8 3.7 3.8 3.8 3.7 3.6 140.6 4.69 7.0 3.6 279 .62 .69 3.6 3.4 4.2 3.8 3.5 3.4 3.3 3.3 3.4 3.4 3.4 3.6 4.1 3.5 3.4 3.8 3.6 3.3 3.1 3.1 5.3 3.3 4.4 4.4 3.3 3.2 3.3 3.8 3.2 3.2 3.1 110.7 3.57 5.3 3.1 220 .47 .55 2.8 2.7 3.1 2.7 2.7 2.8 2.7 2.7 2.7 2.6 2.6 2.7 2.5 2. 2. 2. 2. 2. 10 3.2 2.8 2.7 2.8 3.4 2.7 2.9 2.4 2.3 2.3 13--- 97.8 3.26 13 2.3 194 .43 .48 4.7 3.7 3.6 3.5 3.5 3.5 3.5 3.5 3.3 3.3 3.3 3.4 3.3 3.2 3.1 3.2 3.2 4.4 6.4 4.6 5.1 4.4 4.0 3.8 4.6 3.8 3.6 4.1 3.7 3.6 3.6 118.5 3.82 6.4 3.1 235 .51 .59 3.5 3.4 3.7 3.7 3.4 3.2 3.2 3.2 3.2 8.3 10 3.6 29 59 9.9 5.4 5.2 4.7 4.1 3.9 3.8 e382 7.6 7.7 6.1 3.7 4.9 3.5 3.2 6.2 3.8 606.1 19.6 382 3.2 1200 2.60 2.99 4.9 5.3 3.3 3.1 3.2 3.4 2.9 2.6 2.7 2.8 2.7 6.0 7.5 10 4.9 4.6 2.9 2.7 2.6 2.9 2.9 4.7 3.5 7.9 3.4 10 3.8 3.9 3.2 3.2 127.5 4.25 10 2.6 253 .56 .63 , BY WATER YEAR (WY) 5.57 11.1 1993 3.24 1995 FOR 1997 3346 9 382 2 2 2330 17 2 6640 1 16 13 7 3 8.69 19.5 1992 2.50 1994 WATER YEAR .4 .17 Aug 22 .3 Jun 28 .5 Jun 12 Aug 22 .88 Aug 22 .3 Jun 27 .22 .53 .3 .1 7.60 20.0 1993 1.78 1994 8.67 24.9 1993 3.40 1990 WATER 11. 17. 5. 1670 1. 1. 7500 24. 1. 8600 1. 21. 18 5. 2. 15.6 36.8 1996 4.36 1990 YEARS 1990 9 7 77 Sep 1 Jun 2 Jun Sep 60 Sep 0 Jun 58 42 1 6 22.4 81.6 1996 4.25 1997 - 1997 1996 1994 10 1996 8 1994 8 1994 10 1996 10 1996 21 1994 e Estimated RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD 07 DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October 1994 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 12,9000 mg/L September 10, 1996; Minimum daily mean, 1 mg/L September 11,1991 and 1996 several days. SEDIMENT LOADS: Maximum daily mean, 95,000 tons (86,200 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) January 08, 1995. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 2,220 mg/L January 21, 1997; Minimum daily mean, 3 mg/L May 3, 1997. SEDIMENT LOADS: Maximum daily mean,e3,030 tons (e2,750 tonnes) August 22, 1997; Minimum daily mean, 0.03 ton (0.03 tonne) several days. 289 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 20 18 9.5 9.1 8.8 8.7 8.6 8.3 8.2 8.1 8.2 9.6 8.6 7.9 7.4 7.4 7.3 7.3 7.4 7.4 7.3 7.2 7.0 6.7 6.7 24 9.4 46 11 9.7 9.5 MEAN CONCEN- TRATION (MG/L) OCTOBER 61 37 21 19 19 17 19 22 14 7 7 76 62 30 19 18 20 23 17 11 9 8 12 23 26 707 116 1690 97 31 61 SEDIMENT DISCHARGE (TONS/DAY) 3.2 1.6 .57 .47 .46 .40 .44 .49 .31 .16 .16 4.3 1.5 .65 .38 .35 .39 .46 .34 .22 .18 .15 .23 .41 .47 109 3.5 584 3.0 .81 1.7 MEAN DISCHARGE (CFS) 11 8.6 13 9.5 11 9.2 13 8.9 7.6 11 19 38 29 12 9.4 8.4 18 9.2 7.4 6.9 18 65 17 15 11 9.2 11 10 10 21—— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 'NOVEMBER 11 8.6 13 9.5 11 9.2 13 8.9 7.6 11 19 38 29 12 9.4 8.4 18 9.2 7.4 6.9 18 65 17 15 11 9.2 11 10 10 21 234 47 268 51 257 52 286 52 46 181 576 1680 942 139 40 23 596 57 31 30 1260 1740 305 201 70 29 98 90 84 451 9.7 1.1 20 1.3 11 1.3 24 1.3 .93 9.8 97 425 116 4.9 1.0 .52 83 1.5 .61 .55 203 1470 15 8.8 2.1 .72 4.5 3.3 2.6 43 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 15 13 11 11 10 9.4 8.8 8.4 8.3 8.4 10 8.7 8.4 8.0 8.0 8.4 8.1 8.0 7.8 7.8 8.0 7.6 7.7 8.6 8.7 38 14 18 30 19 14 240 197 176 161 157 155 126 63 56 59 82 88 40 17 8 7 8 6 4 4 4 5 5 42 153 1090 591 656 1190 451 146 13 6.8 5.1 4.6 4.3 4.0 3.0 1.4 1.2 1.3 2.3 2.1 .92 .38 .17 .16 .18 .14 .09 .09 .10 .10 .10 1.2 4.4 549 41 61 171 30 5.7 330.3 720.30 447.3 2563.53 360.1 914.83 290 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED {TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 13 18 12 12 12 10 10 9.8 9.3 8.5 8.7 8.7 8.8 8.5 8.3 8.6 8.6 9.0 9.0 8.9 49 42 27 41 21 14 12 12 12 11 10 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 57 337 103 27 83 97 35 16 8 6 5 5 4 6 7 6 5 36 51 57 2220 1480 629 1170 146 55 51 59 33 15 12 1.9 26 3.4 .85 3.3 2.7 .95 .44 .21 .14 .13 .11 .10 .13 .16 .14 .13 .90 1.2 1.4 467 245 97 155 8.7 2.1 1.6 1.9 1.0 .42 .34 MEAN DISCHARGE (CFS) 30 16 11 e!2 e!3 e!2 e!3 e9.4 e!4 e9.0 e9.4 9.5 9.8 10 9.0 8.6 8.5 9.0 9.2 9.4 14 10 8.9 8.8 8.9 8.7 8.4 8.3 MEAN CONCEN- TRATION (MG/L) FEBRUARY 834 293 40 32 49 40 25 33 66 36 17 12 10 56 92 84 77 70 63 57 246 126 84 48 26 16 10 10 SEDIMENT DISCHARGE (TONS/DAY) 254 26 1.2 e.85 el. 6 el. 4 e.89 e.98 e2.1 el.l e.42 .31 .27 1.7 2.2 2.0 1.8 1.7 1.6 1.5 11 3.5 2.0 1.1 .63 .37 .23 .23 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 8.2 8.5 11 8.9 11 8.5 8.8 9.2 8.7 7.6 7.3 7.7 7.7 7.6 7.7 7.7 7.3 8.1 7.1 6.8 6.8 6.9 7.0 7.3 7.3 7.7 7.8 10 7.5 6.9 6.4 12 14 108 23 108 73 22 16 13 12 15 20 21 20 10 5 7 46 23 7 5 5 5 7 9 11 12 239 65 9 8 .27 .32 3.5 .57 3.7 1.7 .52 .40 .31 .24 .29 .41 .44 .41 .20 .10 .13 1.1 .44 .13 .09 .09 .10 .13 .17 .22 .26 13 1.4 .17 .15 452.7 1024.35 307.8 322.68 247.0 30.96 e Estimated 291 RIO QRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CPS) 1 6.3 2 7.0 3 6.9 4 6.2 5 5.8 6 5.5 7 5.2 8 5.1 9 5.0 10 4.9 11 12 13 14 15 16 17 18 19 20 21 22 23 .6 .6 .6 .4 .5 .4 .3 .3 .2 .2 .2 .1 .0 24 3.9 25 3.8 26 3.7 27 3.8 28 3.8 29 3.7 30 3.6 31 APRIL 9 27 33 7 7 7 9 12 11 9 9 10 11 9 7 6 6 6 7 7 10 15 14 12 14 19 24 20 15 16 .15 .78 .69 .12 .11 .11 .13 .17 .14 .11 .11 .13 .14 .11 .08 .07 .07 .07 .07 .08 .12 .17 .15 .13 .14 .19 .25 .20 .15 .15 —— 3.6 3.4 4.2 3.8 3.5 3.4 3.3 3.3 3.4 3.4 3.4 3.6 4.1 3.5 3.4 3.8 3.6 3.3 3.1 3.1 5.3 3.3 4.4 4.4 3.3 3.2 3.3 3.8 3.2 3.2 3.1 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 17 18 25 18 9 5 7 11 10 7 6 6 13 7 4 3 4 4 4 4 26 14 64 45 23 18 20 23 23 22 20 .17 .17 .32 .18 .08 .04 .06 .10 .09 .07 .05 .06 .17 .06 .03 .03 .04 .04 .03 .03 .59 .13 2.0 1.1 .21 .16 .18 .23 .20 .19 .17 MEAN DISCHARGE (CFS) MEAN ___ CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 2.8 2.7 3.1 2.7 2.7 2.8 2.7 2.7 2.7 2.6 2.6 2.7 2.5 2. 2. 2. 2. 2. 10 3.2 2.8 2.7 2.8 3.4 2.7 2.9 2.4 2.3 2.3 13 19 14 11 18 32 25 16 11 9 7 11 17 16 13 11 9 9 9 341 37 28 23 19 23 14 18 17 14 12 273 56 .14 .10 .09 .13 .23 .19 .12 .08 .06 .05 .08 .12 .11 .09 .07 .06 .06 .06 .32 .21 .17 .15 .26 .10 .15 .11 .09 .08 54 140.6 5.09 110.7 6.98 97.8 113.48 292 RIO GRANDS DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JULY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 4.7 3.7 3.6 3.5 3.5 3.5 3.5 3.5 3.3 3.3 3.3 3.4 3.3 3.2 3.1 3.2 3.2 4.4 6.4 4.6 5.1 4.4 4.0 3.8 4.6 3.8 3.6 4.1 3.7 3.6 3.6 TOTAL 118.5 YEAR e 3346.4 Estimated 4.7 3.7 3.6 3.5 3.5 3.5 3.5 3.5 3.3 3.3 3.3 3.4 3.3 3.2 3.1 3.2 3.2 4.4 6.4 4.6 5.1 4.4 4.0 3.8 4.6 3.8 3.6 4.1 3.7 3.6 3.6 38 25 19 15 12 10 8 7 6 6 8 24 61 22 6 5 7 20 103 31 68 19 13 12 13 13 13 27 15 10 15 .49 .25 .19 .14 .12 .09 .08 .07 .06 .06 .07 .23 .55 .19 .05 .05 .06 .30 4.3 .39 1.2 .23 .14 .13 .16 .13 .13 .33 .15 .10 .15 10.59 10134.18 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 3.5 3.4 3.7 3.7 3.4 3.2 3.2 3.2 3.2 8.3 10 3.6 29 59 9.9 5.4 5.2 4.7 4.1 3.9 3.8 .382 7.6 7.7 6.1 3.7 4.9 3.5 3.2 6.2 3.8 25 23 19 14 8 5 4 5 5 260 436 23 1530 1150 87 16 11 12 15 17 20 1420 81 129 66 15 80 14 12 72 25 .24 .22 .19 .14 .08 .04 .04 .04 .04 17 33 .22 398 785 3.6 .23 .15 .15 .16 .18 .21 B3030 1.8 3.8 1.3 .15 2.3 .13 .10 2.3 .26 606.1 4281.07 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 4.9 5.3 3.3 3.1 3.2 3.4 2.9 2.6 2.7 2.8 2.7 6.0 7.5 10 4.9 4.6 2.9 2.7 2.6 2.9 2.9 4.7 3.5 7.9 3.4 10 3.8 3.9 3.2 3.2 73 124 101 36 18 13 10 8 9 10 10 208 159 306 78 72 28 25 32 27 20 154 28 522 21 504 22 23 20 17 1.2 2.7 .91 .30 .16 .12 .08 .06 .06 .07 .07 6.3 14 15 1.2 1.0 .22 .19 .23 .21 .16 2.8 .29 32 .20 60 .22 .25 .17 .15 127.5 140.32 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT CANAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 293 DATE DEC 1996 28... AU6 1997 22... 22... SEP 24... TIME 1630 1245 1820 1630 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 34 2140 31 13 3040 279 8672 50200 1110 93 3380 119 41 30 60 59 52 39 69 68 65 47 70 76 DATE DEC 1996 28... AUG 1997 22... 22... SEP 24... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 75 57 81 83 86 65 83 88 94 77 95 99 98 85 97 100 100 96 99 100 100 99 100 100 100 100 100 100 294 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT CANAS, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 28... NOV 22... 24... DEC 26... JAN 1997 22... FED 21... JUL 21... AUG 11... 13... 22... SEP 12... TIME 0944 1400 1005 2145 1630 1530 1100 1615 1745 1500 1630 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 11 1200 17 327 29 17 8.5 15 204 1300 12 SEDI- MENT, SUS- PENDED (MG/L) (80154) 510 16600 532 6870 470 485 663 1710 14900 5650 2380 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 15 53800 24 6060 37 22 15 69 8210 19900 77 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 77 71 99 79 95 96 98 99 95 83 100 295 RIO GRANDE DE LOIZA BASIN 50059000 LAGO LOIZA AT DAMSITE HEAR TRXJJILLO ALTO, PR LOCATION.--Lat 18°19'49", long 66°01'00", Hydrologic Unit 21010005, at pumpsite at damsite, and 1.9 mi (3.1 km) south of Trujillo Alto plaza. DRANAIGE AREA.--208 mi 3 (539 km») . ELEVATION RECORDS PERIOD OF RECORD.—December 1987 to current year. Prior to October 1994, published as Lago Loiza at Damsite. GAGE.—Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lake is formed by Loiza Dam, a concrete structure completed in 1954. Useable capacity of impoundment is 30,000 acre-ft (37.0 hmj ). Out flow from lake is controlled by five slide gates in powerplant and pump intake structure, four sluice gates, and concrete spillway with eight radial gates. Lake is used for municipal water supply and intermittent power generation. Gage-height satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 147.42 ft (44.93 m), Sept. 18, 1989; minimum elevation, 108.52 ft (33.08 m), July 18, 1994. EXTREMES FOR CURRENT YEAR.—Maximum elevation 135.44 ft (41.82 m), Feb. 02; minimum elevation, 112.76 ft (34.37 m), July 17. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 98.4 111.5 120.4 Contents in acre-feet 5,000 8,900 13,000 Elevation, in feet 128.6 137.8 147.6 Contents in acre-feet 18,000 26,000 35,000 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES NOV 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN CAL WTR 134.46 A 134.60 134.96 134.34 134.62 134.88 134.56 134.90 A 135.12 134.72 134.20 134.42 134.64 134.82 134.92 134.56 134.66 134.76 134.80 134.61 134.70 134.76 134.80 134.30 134.80 134.76 134.33 134.54 134.64 135.12 134.20 YR 1996 YR 1997 134.92 134.80 135.00 134.68 134.84 134.55 134.82 134.90 134.92 134.46 134.54 134.52 A A 134.40 134.86 134.76 134.04 134.10 134.90 134.20 133.27 134.24 133.60 134.18 134.50 134.78 134.18 134.50 134.20 —— 135.00 133.27 MAX 135.12 MAX 135.18 134.68 133.80 134.00 134.16 134.28 134.40 134.56 134.64 134.70 134.74 134.48 134.74 134.82 134.86 134.88 133.96 133.96 133.92 133.88 133.84 133.84 133.82 133.76 133.72 133.78 134.28 134.30 134.52 134.88 134.80 134.63 134.88 133.72 MIN 130 MIN 112 134.76 134.98 135.02 135.04 135.00 135.00 134.96 134.92 134.88 134.80 135.14 134.46 134.42 134.34 134.26 134.20 134.06 133.96 133.88 133.96 134.96 134.62 134.88 134.28 134.92 135.12 135.18 134.96 135.12 135.16 135.18 135.18 133.88 .07 .76 FEB 134.26 134.38 134.98 134.96 134.78 134.82 135.08 134.66 135.00 134.86 135.00 134.72 135.00 135.04 134.70 134.76 134.78 134.78 134.82 134.84 135.10 134.88 135.10 134.96 134.97 135.10 134.96 134.86 135.10 134.26 MAR 134.82 134.76 134.74 134.74 134.74 134.68 134.56 134.56 134.48 134.32 134.18 134.06 133.96 133.84 133.76 133.72 133.68 133.64 133.52 133.40 133.24 133.08 132.90 132.72 132.52 132.36 132.18 132.06 132.02 131.92 131.78 134.82 131.78 APR 131.62 133.42 135.10 134.92 134.84 134.70 134.54 134.36 134.14 133.94 133.76 133.56 133.38 133.18 132.96 132.74 132.48 132.26 132.04 132.02 131.74 131.44 131.16 130.86 130.56 130.24 129.94 129.58 129.26 128.92 135.10 128.92 MAY 128.56 128.20 127.94 127.56 127.19 126.80 126.41 126.10 125.84 125.78 125.84 125.76 125.70 A A A A A A 124.70 124.86 124.58 124.32 124.02 123.66 123.30 122.96 123.14 123.12 123.34 123.34 128.56 122.96 JUN 123.20 123.02 123.38 123.74 123.64 123.44 123.07 122.75 122.38 122.00 121.58 121.20 120.78 120.52 120.18 119.84 119.36 118.87 118.80 118.60 118.40 118.16 118.02 118.86 118.78 118.64 118.48 118.23 117.99 117.83 123.74 117.83 JUL 117.51 117.15 116.75 116.31 115.90 115.63 115.67 115.44 115.22 114.93 114.63 114.18 113.86 113.57 113.14 112.76 113.02 113.04 113.20 113.94 118.82 123.42 123.84 124.24 124.35 124.22 124.15 125.82 126.27 127.02 127.14 127.14 112.76 AUG 127.11 127.05 127.47 127.48 127.31 127.09 126.82 126.56 126.33 127.23 127.69 127.66 129.10 129.93 129.92 129.87 129.98 130.78 130.86 130.68 130.55 134.60 134.37 134.17 134.62 134.23 134.72 134.61 134.66 134.72 134.14 134.72 126.33 SEP 134.31 134.42 134.48 134.41 134.32 132.90 132.79 133.18 133.39 133.25 133.07 133.30 133.51 133.63 134.15 134.22 134.12 134.10 134.05 133.94 134.01 134.58 134.73 134.72 134.79 134.45 134.57 134.70 134.74 134.53 134.79 132.79 A No gage-height record 296 RIO GRANDE DE LOIZA BASIN 50059000 LAGO LOIZA AT DAMSITE, PR WATER-QUALITY RECORDS at pumphouse at damsite, and 1.9 ml (3.1 km) south of Trujillo Alto LOCATION.—Lat 18°19'49", long 66°01'00 plaza. DRAINAGE AREA.--208 ml 2 (539 km*). PERIOD OF RECORD.—Water years 1974 to current year. HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 02... PB OXYGEN, OXYGEN COLI- ALKA- SPE- WATER DIS- DEMAND, FORM, STREP- LINITY CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI HAT WH CON- FIELD TEMPER- OXYGEN, (PER- ICAL 0.45 FECAL, TOT FET DUCT- (STAND- ATURE DIS- CENT (HIGH UM-MF (COLS. FIELD TIME ANCE ARD WATER SOLVED SATDR- LEVEL) (COLS./ PER MG/L AS (US/CM) UNITS) (DEG C) (MG/L) ATION) (MG/L) 100 ML) 100 ML) CACO3 (00095) (00400) (00010) (00300) (00301) (00340) (31616) (31679) (00410) 1100 240 6.7 27.0 2.3 29 <10 50 220 100 1130 256 6.7 27.5 3.0 38 <10 K69 K31 100 1025 389 6.7 29.0 0.2 3 <10 K19 40 150 1100 196 6.7 30.5 0.5 7 15 84 83 66 RESIDUE NITRO- TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- GEN,AM- AT 105 GEN, GEN, GEN, GEN, GEN, MONIA + NITRO- NITRO- SULFZDE DEO. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC GEN, GEN, DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 02... DATE OCT 1996 24... FEB 1997 20... JDN 04... SEP 02... TOTAL SUS- TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL (MG/L FENDED (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L AS S) (MG/L) AS N) AS N) AS N) AS N) AS N) AS N) AS N) AS NO3) (00745) (00530) (00620) (00615) (00630) (00610) (00605) (00625) (00600) (71887) <0.5 4 0.360 0.030 0.400 0.120 0.53 0.66 1.1 4.7 1 0.570 <0.010 0.580 0.030 0.34 0.36 0.94 4.2 <0.5 <1 0.070 0.120 0.190 0.440 0.60 1.0 1.2 5.4 3 0.230 <0.010 0.240 0.150 0.70 0.86 1.1 4.9 MANGA- METHY- BORON, COPPER, IRON, NESE, ZINC, LENE PHOS- TOTAL TOTAL TOTAL TOTAL TOTAL BLUE PHORUS RECOV- RECOV- RECOV- RECOV- RECOV- CYANIDE ACTIVE TOTAL ERABLE ERABLE ERABLE ERABLE ERABLE TOTAL PHENOLS SUB- (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS P) AS B) AS CO) AS FE) AS HN) AS ZN) AS CN) (UG/L) (MG/L) (00665) (01022) (01042) (01045) (01055) (01092) (00720) (32730) (38260) 0.040 30 <10 90 120 <10 <0.010 1 <0.01 0.040 0.040 60 24 110 240 10 <0.010 <1 0.06 0.140 non-ideal count 297 RIO GRANDE DE LOZZA BASIN 50059050 RIO GRANDE DE LOZZA BELOW DAMSITE, PR LOCATION.—Lat 18°20'33", long 66°00'20", Hydrologic Unit 21010005, on left bank of Highway 175, 1.1 mi (1.8 km) downstream of Lago Loiza Dam. DRAINAGE AREA.—209 mi 2 (541 km*). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—December 1986 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 32 ft (10 m), from topographic map. REMARKS.—Records poor. Flow regulated by Lago Loiza Dam. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV JAN FEB MAR APR MAY JUN JUL AUG SEP 1 45 1.6 2 e43 180 3 e!75 2.6 4 26 143 5 278 3.1 6 e21 178 7 21 805 8 178 151 9 17 e!24 10 223 258 11 157 460 12 196 2050 13 220 1190 14 5.2 293 15 e4.3 252 16 e3 . 9 5.0 17 e3.6 308 18 e200 413 19 e6.0 387 20 eS.O 5.9 21 e4.5 430 22 e!70 1460 23 e6.0 106 24 eS.O 389 25 e4.0 7.2 26 e350 e6.1 27 e20 6.0 28 e250 264 29 e300 8.9 30 e2.2 295 31 1.9 TOTAL 2941.6 10182.4 MEAN 94.9 339 MAX 350 2050 MIN 1.9 1.6 AC-FT 5830 20200 CFSM .45 1.62 IN. .52 1.81 8.5 352 7.1 7.0 6.8 6.8 6.4 6.2 6.2 6.0 351 e6.0 e5.4 e5.4 e6.3 e6.0 e5.6 e5.8 e5.7 e5.6 e5.6 e5.9 e5.6 e5.6 e5.5 e5.8 e6.4 e5.8 e7.0 e6.4 e5.8 881.2 28.4 352 5.4 1750 .14 .16 e5.6 e5.6 e5.4 e5.2 eS.O eS.O eS.O e4.9 e5.2 e4.9 eS.O e4.8 e4.9 eS.O eS.O e5.2 e5.2 e5.2 eS.O e4.9 e4.8 e4.8 e4.8 e4.8 eS.O e5.4 e5.4 e5.4 e5.2 eS.O e5.2 157.8 5.09 5.6 4.8 313 .02 .03 e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.2 e5.2 e5.2 e5.4 e5.4 eS.O e5.2 eS.O e5.2 e5.2 eS.O eS.O eS.O e5.2 eS.O e5.2 eS.O e4.9 e5.2 e5.2 e5.2 e5.4 —— 145.1 5.18 5.4 4.9 288 .02 .03 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1987 MEAN 222 495 MAX 842 2732 (WY) 1991 1988 MIN 44.7 37.6 (WY) 1992 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 340 2603 1988 17.2 1994 FOR 151 733 1992 2.49 1995 69.1 242 1989 4.52 1990 e5.2 e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.4 e5.2 e5.4 e5.4 e5.4 eS.O e5.4 e5.8 e5.6 e5.8 e5.4 e5.4 e5.4 e5.4 e5.6 e5.8 e5.6 e5.2 e4.9 e4.6 e4.2 e4.1 e4.1 e3.9 161.0 5.19 5.8 3.9 319 .02 .03 - 1997 44.9 299 1989 5.19 1997 1996 CALENDAR YEAR 184152 503 110000 1 1 365300 2 32 461 5 2 .7 Sep 10 .2 Jun 5 .3 Jun 1 .41 .78 .8 .4 e3.9 e3.9 e4.1 e4.0 e3.8 e3.7 e3.6 e3.6 83.5 83.4 83.4 83.3 83.3 83.2 83.2 84.4 83.2 83.4 83.4 83.7 83.5 83.5 83.9 84.6 85.3 84.1 83.9 87.6 4.7 4.0 —— 117.1 3.90 7.6 3.2 232 .02 .02 4.0 3.9 3.9 3.9 3.9 3.7 3.8 3.7 3.7 3.7 3.6 3.5 3.6 3.6 4.1 3.9 3.8 3.9 4.0 4.8 6.3 5.1 4.3 4.3 4.2 4.0 3.9 4.0 3.8 4.0 4.1 125.0 4.03 6.3 3.5 248 .02 .02 4.2 4.2 4.4 5.2 5.0 .5 .5 .3 .5 .5 .9 .6 .3 .0 3.9 3.8 3.6 e3.5 3.4 2.9 82.9 2.9 3.4 3.6 3.8 3.3 3.3 2.6 2.5 2.4 —— 114.9 3.83 5.2 2.4 228 .02 .02 2.2 2.1 2.2 2.3 2.5 2.7 2.7 3.5 2.9 2.8 2.6 2.4 2.2 1.9 1.8 2.6 5.5 4.9 5.0 11 7.7 4.4 3.3 3.2 3.5 3.0 2.6 3.1 2.5 2.9 3.5 105.5 3.40 11 1.8 209 .02 .02 2.4 2.1 2.2 2.4 2.3 2.5 2.7 2.8 3.0 3.2 3.7 3.2 821 6.1 3.6 3.4 4.6 4.1 3.0 2.9 4.8 1140 528 1750 8645 262 11 8222 e!3 89.1 297 4963.1 160 1750 2.1 9840 .77 .88 el? 113 ell ell elO 8394 881 e!5 e!4 e!4 e!4 e9.4 15 19 11 8.1 8.1 9.4 10 9.4 9.5 8.9 172 173 9.0 659 158 6.5 6.7 184—— 2180.0 72.7 659 6.5 4320 .35 .39 , BY WATER YEAR (WY) 29.3 112 1987 1.20 1995 FOR 1997 22074 60 2050 1 2 18100 18 43790 3 179 5 2 85.2 367 1992 1.03 1995 WATER YEAR .7 .5 NOV 12 .6 NOV 1 .3 Jun 29 Aug 22 .56 Aug 22 .29 .93 .2 .9 171 784 1987 1.96 1994 160 672 1993 1.62 1994 WATER 224 652 37 110000 223000 49 162400 1 14 368 7 2 198 718 1988 2.21 1994 YEARS 1987 .8 Sep .42 May .49 Aug Sep .31 Sep .07 .58 .9 .3 726 4255 1996 29.7 1990 - 1997 1988 1994 10 1996 13 1995 11 1994 10 1996 10 1996 e Estimated 298 RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.— Water years 1987 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: December 1986 to current year. INSTRUMENTATION.— Automatic sediment sampler, since 1987. EXTREMES FOR PERIOD OF DAILY RECORD.» SEDIMENT CONCENTRATION: Maximum daily mean, 4,290 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 1,500,000 tons (1,360,000 tonnes) September 10, 1996; Minimum daily mean, <0.01 tons (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 328 mg/L September 3, 1997; minimum daily mean, 9 mg/L February 26-28, 1997. SEDIMENT LOADS: Maximum daily mean, 1,530 tons (1,390 tonnes) August 24, 1997; minimum daily 0.06 tons (0.05 tonne) July 12-13, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 45 e43 e!75 26 278 821 21 178 17 223 157 196 220 5.2 e4.3 e3.9 e3.6 e200 e6.0 eS.O e4.5 e!70 e6.0 eS.O e4.0 e350 e20 e250 e300 e2.2 1.9 46 45 49 40 51 37 36 46 36 45 37 39 40 26 23 22 22 23 24 24 23 43 16 10 17 48 58 45 69 35 18 5.6 eS.l eSO 2.8 92 e2.1 2.0 52 1.6 67 46 57 81 .37 e.27 e.23 e.22 e.25 e.34 e.36 e.30 e7.2 e3.8 e.15 e.20 elS e21 e!2 e52 e6.5 .09 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER DECEMBER TOTAL 2941.6 584.48 1.6 180 2.6 143 3.1 178 805 151 e!24 258 460 2050 1190 293 252 5.0 308 413 387 5.9 430 1460 106 389 7.2 e6.1 6.0 264 8.9 295 10182.4 18 28 21 32 22 30 52 19 28 34 42 124 75 42 38 25 38 49 52 26 42 86 30 43 31 28 26 43 30 42 .08 51 .15 41 .19 40 250 40 e33 70 149 1160 379 97 76 .34 74 134 116 .42 120 654 22 118 .60 .47 .42 78 .71 79 3784.38 8.5 352 7.1 7.0 6.8 6.8 6.4 6.2 6.2 6.0 351 e6.0 e5.4 e5.4 e6.3 e6.0 e5.6 e5.8 e5.7 e5.6 e5.6 e5.9 e5.6 e5.6 eS.S e5.8 e6.4 eS.8 e7.0 e6.4 e5.8 881.2 28 47 11- 27 27 26 26 26 26 25 25 40 9< 25 26 27 29 30 30 30 29 29 29 29 29 29 28 28 28 28 28 28 28 .65 r .51 .50 .49 .48 .45 .43 .42 .41 .40 .39 .40 .45 .49 .47 .46 .46 • 45 .44 .45 .45 .43 .43 .43 .46 .46 .48 .50 .45 226.29 e Estimated 299 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) e5.6 e5.6 e5.4 e5.2 eS.O eS.O eS.O e4.9 e5.2 e4.9 eS.O e4.8 e4.9 eS.O eS.O e5.2 e5.2 e5.2 eS.O e4.9 e4.8 e4.8 e4.8 e4.8 eS.O e5.4 e5.4 e5.4 e5.2 eS.O e5.2 RIO QRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 27 27 27 27 27 27 26 26 26 26 26 26 26 25 25 25 25 25 25 24 24 24 24 43 24 23 22 22 21 21 20 e.42 e.41 e.40 e.38 e.37 e.36 e.36 e.35 e.36 e.35 e.34 e.34 e.33 e.34 e.34 e.34 e.35 e.35 e.34 e.33 e.32 e.31 e.31 e.55 e.31 e.32 e.33 e.32 e.30 e.28 e.28 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.2 e5.2 e5.2 e5.4 e5.4 eS.O e5.2 eS.O e5.2 e5.2 eS.O eS.O eS.O e5.2 eS.O e5.2 eS.i) e4.9 e5.2 e5.2 e5.2 e5.4 —— 19 19 18 18 17 17 16 16 15 15 15 14 14 13 13 13 12 12 12 11 11 11 10 10 10 9 9 9 —— ... —— e.27 e.26 e.26 e.25 e.25 e.25 e.23 e.22 e.22 e.22 e.21 e.20 e.19 .18 .18 .18 .17 .16 .16 e.16 e.15 e.15 e.14 e.13 e.13 e.13 e.13 e.13 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH e5.2 e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.4 e5.2 e5.4 e5.4 e5.4 eS.O e5.4 e5.8 e5.6 e5.8 e5.4 e5.4 e5.4 e5.4 e5.6 e5.8 e5.6 e5.2 e4.9 e4.6 e4.2 e4.1 e4.1 e3.9 10 10 11 12 13 14 15 16 17 19 20 22 23 24 24 25 25 26 27 27 28 28 29 30 31 31 32 31 31 30 30 e.14 e.15 e.16 e.17 e.19 e.20 e.22 e.23 e.25 e.27 e.29 e.31 e.32 e.33 e.37 e.38 e.39 e.39 e.39 e.40 e.41 e.42 e.45 e.46 e.44 e.43 e.41 e.37 e.35 e.34 e.32 TOTAL 157.8 10.79 145.1 5.31 161.0 9.95 e Estimated 300 RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL APRIL e3.9 e3.9 e4.1 e4.0 e3.8 e3.7 e3.6 e3.6 e3.5 e3.4 e3.4 e3.3 e3.3 e3,2 e3.2 e4.4 e3.2 e3.4 e3.4 e3.7 e3.5 e3.5 e3.9 e4.6 e5.3 e4.1 e3.9 e7.6 4.7 4.0 117.1 29 29 28 28 28 27 27 26 26 25 25 24 24 24 23 23 23 23 23 23 24 24 24 24 24 24 23 26 23 22 .31 .31 .31 .31 .29 .27 .26 .25 .25 .24 .23 .22 .22 .21 .20 .27 .20 .21 .21 .23 .22 .22 .25 .30 .35 .26 .24 .57 .30 .24 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY 4.0 3.9 3.9 3.9 3.9 3.7 3.8 3.7 3.7 3.7 3.6 3.5 3.6 3.6 4.1 3.9 3.8 3.9 4.0 4.8 6.3 5.1 4.3 4.3 4.2 4.0 3.9 4.0 3.8 4.0 4.1 21 20 19 18 18 17 16 16 15 14 14 13 13 12 12 11 13 15 17 20 45 85 87 92 96 101 107 112 117 118 118 .23 .21 .20 .19 .19 .17 .17 .16 .15 .14 .13 .12 .12 .12 .13 .12 .13 .15 .18 .25 .94 1.2 1.0 1.1 1.1 1.1 1.1 1.2 1.2 1.3 1.3 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 4.2 4.2 4.4 5.2 5.0 4.5 4.5 4.3 .5 .5 .9 .6 .3 .0 3.9 3.8 3.6 e3.5 3.4 2.9 e2.9 2.9 3.4 3.6 3.8 3.3 3.3 2.6 2.5 2.4 118 118 118 118 117 112 106 101 96 91 87 83 79 80 81 82 83 84 84 77 70 64 58 53 48 44 24 12 13 13 1.4 1.3 1.4 1.7 1.6 1.4 1.3 1.2 1.2 1.1 1.2 1.0 .92 .86 .85 .83 .81 e.79 .76 .61 e.55 .50 .53 .52 .50 .39 .22 .09 .09 .09 7.95 125.0 15.80 114.9 25.71 e Estimated RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 301 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 2.2 2.1 2.2 2.3 2.5 2.7 2.7 3.5 2.9 2.8 2.6 2.4 2.2 1.9 1.8 2.6 5.5 4.9 5.0 11 7.7 4.4 3.3 3.2 3.5 3.0 2.6 3.1 2.5 2.9 3.5 JULY 14 14 15 15 16 16 17 17 18 18 12 10 11 13 15 20 25 26 25 29 27 26 24 23 22 21 21 20 19 38 74 TOTAL 105.5 —— YEAR e 22074.7 Estimated MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST .08 .08 .09 .09 .11 .12 .12 .16 .14 .14 .09 .06 .06 .07 .07 .14 .38 .34 .34 .91 .57 .30 .22 .20 .21 .17 .14 .16 .13 .39 .71 6.79 9628.25 2.4 2.1 2.2 2.4 2.3 2.5 2.7 2.8 3.0 3.2 3.7 3.2 621 6.1 3.6 3.4 4.6 4.1 3.0 2.9 4.8 1140 528 1750 6645 262 11 6222 613 e9.1 297 4963.1 63 59 55 52 48 45 42 39 34 30 26 23 33 27 26 24 24 24 22 21 23 62 51 85 91 230 36 47 31 29 68 —— .41 .34 .33 .33 .30 .31 .31 .30 .28 .25 .26 .20 e3.1 .46 .25 .22 .30 .26 .18 .17 .33 1120 165 1530 6253 1020 1.1 658 el.l e.72 250 4407.81 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 617 113 ell ell elO 6394 681 615 614 614 e!4 69 15 19 11 8 8 9 10 9 9 8 172 173 9 659 158 6 6 184 .4 .1 .1 .4 .4 .5 .9 .0 .5 .7 34 288 328 147 73 42 39 37 36 34 33 32 40 175 136 111 91 75 61 50 41 34 58 40 37 39 29 27 26 31 1.6 108 9.9 4.2 2.0 665 68.0 el. 5 el. 4 el. 3 el. 2 6.83 2.6 9.2 4.2 2.4 2.0 1.9 1.7 1.3 1.1 .82 87 31 .90 147 10 .47 .47 34 2180.0 542.99 302 RIO GRANDE DE LOIZA BASIN 50059050 RXO GRANDE DE LOIZA BELOW DAMSITE LOIZA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- CHARGE, INST. SEDI- CUBIC MENT, SUS- DATE AUG 1997 26... SEP 23... TIME PER 1011 1780 0734 1630 SEDI- MENT, DIS- CHARGE, SUS- SED. SUSP. FALL DIAM. SED • SUSP. FALL DIAM. SED • SUSP. PALL DIAM. FINER % FINER % FINER PENDED FENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) 13800 66300 807 3550 13 65 16 72 19 74 DATE AUG 1997 26... SEP 23... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 31 78 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 51 86 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 83 94 SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM (70332) 94 97 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 98 98 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 99 RIO GRANDE DE LOIZA BASIN 50059050 RZO GRANDB DE LOIZA BELOW DAMSITE LOIZA, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 303 DATE JUN 1997 13... SEP 03... 24... 26... TIME 0845 1014 1402 1412 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 4.5 11 2400 4930 SEDI- MENT, SUS- PENDED (MG/L) (80154) 79 305 74 98 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 0.96 9.1 480 1300 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 99 89 92 92 304 RIO GRANDE DE LOIZA BASIN 50059100 RIO GRANDE DE LOIZA BELOW TRUJILLO ALTO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°21'35", long 66°00'15", 100 ft (30 m) downstream of Highway 181 bridge, 0.4 mi (0.6 km) northwest of Trujillo Alto plaza, and 2.2 mi (3.5 km) northeast of Lago Loiza Reservoir. DRAINAGE AREA. —213 mi> (552 km2 ). PERIOD OF RECORD.—Water years 1981 to current year. REMARKS: Flow controlled by Lago Loiza reservoir. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1200 55 1040 29 0900 4 1205 14 HARD- NESS TOTAL (MG/L DATE AS CAC03) (00900) .0 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 380 354 540 336 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.8 6.5 7.3 7.4 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 27.5 0 24.5 3 29.0 2 31.5 7 SODIUM AD- SORP- TION RATIO (00931) .60 .7 .6 .5 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 6.5 8.4 7.6 7.8 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 81 99 99 106 11 <10 13 14 2800 290 K160 3900 CHLO- K110 240 70 K190 SULFATE RIDE, SULFIDE TOTAL (MG/L AS S) (00745) DIS- DIS- SOLVED SOLVED (MG/L AS S04) (00945) (MG/L AS CL) (00940) OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... 130 -- 190 110 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.14 0.13 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.42 0.31 0.64 0.60 33 — 45 28 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 29 -- 32 24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.2 0.81 1.2 12 — 18 11 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 210 -- 339 214 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.9 5.1 3.6 5.4 25 __ 39 22 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 31.0 — 3.66 8.20 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.050 0.100 0.080 0.9 __ 1 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 1 <1 12 15 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 -- 2.8 — 2.8 2.9 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.690 0.830 0.160 0.600 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 -- 107 150 230 150 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 •eO.010 0.031 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 — 70 — <0.5 _- <0.5 — NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.700 0.840 0.170 0.630 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 -- 17 -_ 23 15 NITRO- GEN* AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.030 0.030 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — 1 -- 27 -- 41 22 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.39 0.28 0.61 0.58 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 24 — K » non-ideal count DATE OCT 1996 24... FEE 1997 20... JUN 04... SEP 04... RIO GRANDE DE LOIZA BASIN 50059100 RIO GRANDE DE LOIZA BELOW TRUJILLO ALTO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L 100 300 MANGA- NESE, MERCORY TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L SILVER, ZINC, SELE- TOTAL TOTAL NIUM, RECOV- RECOV- CYANIDE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 40 160 <0.10 0.22 <1 <1 <1 <1 10 <0.010 10 <0.010 <1 MBTHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 0.02 0.06 305 306 RIO GRANDE DE LOXZA BASIN 50061800 RIO CANOVANAS NEAR CAMPO RICO, PR LOCATION.--Lat 18°19'08", long 65°53'21", Hydrologic Unit 21010005, at upstream side of bridge, on paved secondary road, 0.4 mi (0.6 km) northeast of junction of Highways 185 and 186, 1.5 mi (2.4 km) south of Campo Rico, and 4.4 mi (7.1 km) south of Loiza. DRAINAGE AREA.--9.84 mi* (25.48 km*). PERIOD OF RECORD.--March 1967 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 225 ft (68 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 18 17 2 18 27 3 25 15 4 18 14 5 15 20 6 54 27 7 27 117 8 20 38 9 16 23 10 17 19 11 22 25 12 14 262 13 13 107 14 12 44 15 11 34 16 11 26 17 11 67 18 10 64 19 9.5 39 20 10 33 21 10 40 22 10 364 23 11 68 24 9.8 180 25 11 71 26 el20 47 27 e36 40 28 e68 70 29 35 50 30 21 87 31 15 —— TOTAL 698.3 2035 MEAN 22.5 67.8 MAX 120 364 MIN 9.5 14 AC-FT 1390 4040 CFSM 2.29 6.89 IN. 2.64 7.69 STATISTICS OF MONTHLY MEAN MEAN 40.6 44.9 MAX 273 125 (WY) 1971 1985 MIN 6.74 6.66 (WY) 1968 1981 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 60 46 38 36 33 30 28 26 24 23 229 62 36 30 34 34 28 24 22 21 22 20 19 18 18 27 25 57 61 44 30 1205 38.9 229 18 2390 3.95 4.56 DATA 32.6 116 1971 5.82 1968 24 22 19 18 20 17 17 20 18 15 15 13 13 12 12 11 10 10 10 25 89 165 87 137 76 43 35 37 34 29 45 1098 35.4 165 10 2180 3.60 4.15 FOR WATER 25.2 62.4 1969 6.66 1977 109 40 31 31 39 32 24 23 33 27 24 26 47 28 23 21 18 18 29 25 64 56 30 28 28 25 22 20 ... —— 921 32.9 109 18 1830 3.34 3.48 YEARS 1967 19.7 48.4 1988 4.04 1977 20 20 23 28 31 22 18 29 23 18 17 16 16 15 16 16 15 15 14 13 14 13 13 13 13 13 14 16 20 17 15 546 17.6 31 13 1080 1.79 2.06 - 1997 14.1 36.2 1969 3.54 1977 FOR 1996 CALENDAR YEAR 15118. 41. 4230 5. 6. 29990 4. 57. 60 14 6. 5 3 Sep 10 4 Apr 3 0 Mar 28 20 16 6 13 17 32 17 15 14 13 11 12 11 12 11 11 11 10 10 9.4 9.3 9.1 14 9.6 9.1 8.6 8.4 8.5 8.2 8.5 8.7 8.0 7.6 —— 347.0 11.6 32 7.6 688 1.18 1.31 7.7 7.7 7.7 7.6 7.7 7.3 9.1 21 16 14 10 9.1 9.6 16 9.6 8.2 8.4 8.1 7.2 6.7 7.1 8.1 7.3 6.9 7.0 6.4 8.0 24 13 21 9.2 316.7 10.2 24 6.4 628 1.04 1.20 6.9 7.4 19 12 7.6 6.8 6.3 5.4 5.5 5.1 5.2 5.2 5.0 .9 .5 .1 .0 .0 3.9 4.2 4.2 3.8 5.5 9.3 6.1 .6 .3 .3 .0 .0 --- 177.1 5.90 19 3.8 351 .60 .67 3.9 3.9 4.0 3.9 4.4 4.4 4.2 4.3 7.5 13 11 9.7 9.0 8.3 8.8 10 11 10 9.8 21 43 28 29 17 13 12 13 20 17 13 18 385.1 12.4 43 3.9 764 1.26 1.46 15 13 12 18 17 12 9.8 9.0 13 26 18 12 13 14 11 11 23 58 21 14 12 262 42 22 28 14 14 14 12 13 13 785.8 25.3 262 9.0 1560 2.58 2.97 13 11 9.0 7.6 7.4 7.7 9.0 9.5 15 12 11 14 17 35 20 17 14 13 13 12 15 21 18 18 12 45 27 18 17 18—— 476.2 15.9 45 7.4 945 1.61 1.80 , BY WATER YEAR (WY) 15.0 53.2 1971 4.36 1994 FOR 1997 8991 24 364 3 4 4010 9 17830 2 33 44 15 7 27.6 93.2 1969 4.28 1974 WATER YEAR .2 .6 Nov 22 .8 Jun 22 .0 Jun 28 Nov 22 .71 Nov 22 .50 .99 .0 18.0 63.7 1970 2.80 1974 19.1 63.7 1979 3.72 1974 WATER 27. 58. 10. 4230 . 1. 15000 13. . 19540 2. 37. 43 12 5. 25.4 137 1979 5.69 1991 YEARS 1967 0 0 5 Sep 80 Jul 5 Jul Sep 10 Sep 80 Jul 74 25 1 38.1 196 1996 5.20 1967 - 1997 1971 1994 10 1996 24 1977 18 1977 13 1982 13 1982 24 1977 e Estimated 307 ATLANTIC OCEAN LAS PIEDRAS Csr Mop orec EXPLANATION ^0670 SURFACE-WATER STATION AND NUMBER V0725 QUALITY-OF-WATER STATION AND NUMBER DA(LY SED |MENT STATION AND NUMBER NUMBER 01 23456 KILOMETERS 01234 MILES Figure 20.--Northeastern river basins the Rfo Herrera to Ri'o Ant6n Ruiz basins. 308 RIO ESPIRITU SANTO BASIN 50063440 QUEBRADA SONADORA NEAR EL VERDE, PR LOCATION.—Lat 18°19'24", long 65°49'03", Hydrologic Unit 21010005, in Caribbean National Forest, at El Yunque, 0.6 mi (1.0 km) upstream from Rio Espiritu Santo, 0.2 mi (0.3 km) upstream from Highway 186, and about 1.2 mi (1.9 km) south of El Verde. DRAINAGE AREA.—1.01 mi* (2.62 km1 ). PERIOD OF RECORD.—March 1983 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 1,230 ft (375 m), from topographic map. REMARKS.—Records poor. REVISIONS.—The maximum discharges for some water years have been revised as shown in the following tables. They supersede figures published in the reports for 1984-1986, 1988, 1989, and 1992-1995. Water Discharge Gage-height Water Year Date (ftVs) (ft) Year Date 1984 Dec. 2, 1983 1,260 8.60 1992 May 1, 1985 May 14, 1985 1,820 9.36 1993 Sept. 15, 1986 Aug. 24, 1986 1,790 9.32 1994 Oct. 22, 1988 Dec. 7, 1987 1,870 9.42 1995 Oct. 20, 1989 Sept. 18, 1989 1,340 8.72 DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO DAY OCT NOV 1 1.5 1.6 2 1.6 e!9 3 1.5 e!9 4 1.1 e8.0 5 6.9 e7 . 8 6 9.5 e26 7 5.0 e4 . 8 8 9.6 e4.5 9 4.7 e2.4 10 8.3 e2.4 11 2.0 e2 . 0 12 1.5 e2.0 13 7.9 e3 . 0 14 1.9 e2.1 15 .89 el. 9 16 7.2 e2 . 2 17 2.6 e2.1 DEC .25 1.2 .65 .44 .49 .18 .13 5.9 3.7 .89 1.3 15 14 1.3 1.8 37 e60 18 3.7 el. 7 e!20 19 6.1 el. 9 20 1.4 el. 2 21 .89 el. 2 22 1.1 el.O 23 27 el.O 24 20 e3.9 25 3.1 el. 5 26 2.6 el. 5 27 1.3 e.93 28 .96 el. 5 29 .85 3.2 30 .71 1.1 31 1.1 TOTAL 144.50 132.43 MEAN 4.66 4.41 MAX 27 26 MIN .71 .93 AC-FT 287 263 CFSM 4.62 4.37 IN. 5.32 4.88 e25 e3.5 e3.1 e2.5 e2.1 el. 8 el. 9 el. 7 el. 9 e4.0 e2.0 el. 9 el. 8 317.43 10.2 120 .13 630 10.1 11.69 JAN el. 6 el. 6 el. 6 el. 6 e2.0 e3.7 e!5 e!4 e2.1 el. 4 e2.7 e!4 e2.5 e45 e24 e21 e5.2 e8.0 e20 e50 e!4 elO e6.8 elO eS.O e3.1 e6.0 e37 e9.0 3.2 4.2 345.3 11.1 50 1.4 685 11.0 12.72 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN 5.69 9.37 MAX 16.8 19.8 (WY) 1986 1985 MIN .22 2.47 (WY) 1993 1991 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 8.11 20.9 1988 .92 1990 FOR 6.85 11.1 1996 3.42 1985 DAILY FEB 3.7 2.2 10 8.8 5.3 25 12 3.0 2.6 1.8 1.4 1.1 1.0 1.1 .95 1.1 1.0 .95 1.4 1.2 .99 .93 .90 15 3.0 1.3 1.0 .85 .76 —— 110.33 3.80 25 .76 219 3.77 4.06 YEARS 1983 6.14 11.9 1988 1.56 1992 Discharge (ftVs) 1992 993 1993 688 1993 537 1994 685 SEPTEMBER 1996 Gage-height (ft) 8.14 7.56 7.20 7.56 MEAN VALUES MAR .68 .65 .73 .74 17 4.7 4.3 5.2 9.4 1.9 6.4 2.5 1.3 1.0 .97 1.9 1.2 .99 .82 .63 .50 .40 .34 .28 .21 .35 1.8 6.8 5.0 .67 .42 79.78 2.57 17 .21 158 2.55 2.94 - 1996 4.82 14.3 1990 1.53 1993 1995 CALENDAR YEAR 2467. 6. 120 . . 4890 6. 90. 17 2. . 03 76 Dec 18 11 Fab 14 21 Apr 27 69 86 2 44 APR .29 .19 .13 55 4.1 .91 .63 .52 .45 .40 .37 19 4.6 4.5 16 10 1.4 1.0 .70 .72 e.99 el. 4 e26 el. 5 el. 5 el. 8 el. 4 e2.1 e5.6 el. 6 —— 164.80 5.49 55 .13 327 5.44 6.07 MAY el.l e.92 e.90 e.80 e2.5 09.8 05.2 07.8 04.6 02.2 02.1 e!2 03.5 02.2 el. 7 1.3 1.1 .88 .81 .93 1.3 1.9 2.9 5.4 .94 .66 .56 .45 .41 .36 .59 77.81 2.51 12 .36 154 2.49 2.87 JUN 1.1 4.2 1.5 14 5.3 14 9.3 3.1 1.1 1.1 20 26 11 20 46 31 5.7 8.3 3.7 2.0 3.9 13 2.9 1.4 1.2 1.1 1.5 7.1 1.2 .88 —— 262.58 8.75 46 .88 521 8.67 9.67 JUL .78 .69 .95 .62 .51 .52 1.4 75 11 4.5 1.6 14 10 e44 elO 03.9 03.2 03.0 02.5 012 02.3 el. 6 1.3 1.7 15 12 1.7 3.4 2.4 1.2 2.3 245.07 7.91 75 .51 486 7.83 9.03 AUG 11 4.9 25 16 12 6.9 2.0 1.6 3.2 1.2 .94 1.2 36 52 9.4 20 5.2 2.1 2.0 1.2 .97 .80 26 13 2.2 1.3 1.2 2.7 1.1 .76 .65 264.52 8.53 52 .65 525 8.45 9.74 SEP .45 .32 .28 .36 2.4 1.2 .51 10 61 0425 029 02.7 2.2 2.9 21 020 el. 4 02.3 02.4 04.2 012 el. 6 el. 5 el. 5 el. 4 02.0 06.8 029 07.6 03.5 —— 656.52 21.9 425 .28 1300 21.7 24.18 , BY WATER YEAR (WY) 4.80 9.76 1987 1.09 1984 FOR 1996 2801 7 425 4020 11 5560 7 103 19 2 7.81 14.3 1992 2.51 1996 6.06 13.7 1987 .98 1985 WATER YEAR .07 .65 .13 .39 .35 .06 .58 .17 .0 .65 Sep 10 Dec 7 Mar 20 Sep 10 Sep 10 Dec 7 6.62 12.7 1983 2.33 1991 6.73 14.2 1988 .50 1993 WATER YEARS 1983 6.63 9.32 3.91 425 .00 Sep Aug .01 Mar 4020 11.35 .00 4800 6.56 89.15 17 2.6 .43 Sep Sep Aug 7.28 21.9 1996 2.45 1986 - 1996 1988 1994 10 1996 14 1993 31 1994 10 1996 10 1996 13 1993 a Estimated RIO ESPIRITU SANTO BASIN 50063440 QUEBRADA SONADORA NEAR EL VERDE, PR—Continued DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 309 DAY OCT NOV 1 1.7 5.6 2 2.3 12 3 4.6 3.1 4 1.8 3.3 5 1.4 17 6 1.2 3.9 7 1.8 44 8 1.5 4.0 9 1.2 11 10 3.9 2.4 11 1.6 24 12 1.4 e64 13 3.1 elS 14 2.2 e7 . 0 15 1.3 e4.5 16 1.1 e2.9 17 .99 e!6 18 .94 e6.2 19 .89 e4.0 20 .84 e2.8 21 .80 e2.9 22 .77 e34 23 .98 eS.O 24 1.1 e52 25 2.3 e7.2 26 36 e3.3 27 4.6 e2 . 5 28 22 e!7 29 13 e4.0 30 1.6 e30 31 1.5 —— TOTAL 120.41 410.6 MEAN 3.88 13.7 MAX 36 64 MIN .77 2.4 AC -FT 239 814 CFSM 3.85 13 . 6 IN. 4.43 15.12 DEC eS.O e4.5 e2.4 e2.4 e2.2 e2.0 el. 8 el. 6 el. 5 el. 7 e40 eB.O e2.7 e2.0 e2.4 elO e2.5 el. 6 1.5 1.4 1.4 1.9 1.5 3.8 1.8 e4.1 e6.2 elO e24 e7.4 e4.1 163.4 5.27 40 1.4 324 5.22 6.02 JAN e2.5 e2.8 el. 9 el. 4 e2.2 el. 9 el. 7 el. 4 el. 7 el. 3 el. 2 el.l el.O e.98 e.90 e.82 .77 .73 5.3 11 e36 e46 e36 e41 e9.0 e7.8 e3.4 e6.4 e5.2 e3.9 e4.8 242.10 7.81 46 .73 480 7.73 8.92 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN 5.56 9.68 MAX 16.8 19.8 (WY) 1986 1985 MIN .22 2.47 (WY) 1993 1991 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 7.90 20.9 1988 .92 1990 FOR 6.92 11.1 1996 3.42 1985 FEB e20 eS.O e4.1 e3.9 e!2 elO e3.0 e2.8 elS e3.3 e2.7 e5.2 e20 e3.4 e2.4 e2.0 el. 8 el. 8 elO e4.0 e29 elO e3.1 e3.1 e2.8 e3.2 e2.2 el. 7 ___ ___ ___ 187.5 6.70 29 1.7 372 6.63 6.91 YEARS 1983 6.18 11.9 1988 1.56 1992 MAR 1.7 3.1 6.8 6.3 13 2.8 1.9 11 8.0 1.9 1.5 2.5 2.6 1.7 2.7 3.1 el. 3 el.l el. 2 el.l el.O e.98 e.92 e.88 e.85 .83 .80 .78 1.0 .89 .72 84.95 2.74 13 .72 168 2.71 3.13 - 1997 4.67 14.3 1990 1.53 1993 1996 CALENDAR YEAR 2901. 7. 425 . . 5750 7. 106. 20 2. . 12 93 Sap 10 13 Apr 3 39 Mar 20 85 85 3 71 APR .68 2.1 2.7 2.6 4.3 1.1 .88 .84 .79 .76 .78 .77 .77 .64 .50 .48 .46 .50 .67 .79 .51 .43 .41 .38 .36 .35 .37 .36 .33 .33 ___ 26.94 .90 4.3 .33 53 .89 .99 MAY .32 .32 .31 .31 .31 .31 19 e24 el 6 2.2 11 3.1 9.9 2.5 1.2 2.9 3.6 1.4 1.0 1.1 e2.2 el.O e.88 e.93 e.82 e.76 el.l el. 7 ell e3.0 e2.0 126.17 4.07 24 .31 250 4.03 4.65 JUN e4.3 e35 e25 el.O e.89 e.86 e.80 e.77 e.74 e.71 e.70 e.68 el.l e3.2 e.90 e.73 e.70 e.73 el. 6 e4.3 e4.7 el. 4 e!6 e6.4 e2.7 1.7 1.1 .89 .83 .80 ___ 121.23 4.04 35 .68 240 4.00 4.47 JUL .78 .69 .65 .65 .72 1.3 1.5 1.5 2.6 2.3 1.0 .90 4.0 1.8 1.3 8.3 3.6 1.5 8.4 18 e23 e5.6 e!3 el. 7 el. 7 e2.1 el. 2 el. 5 el. 4 e2.0 ell 125.69 4.05 23 .65 249 4.01 4.63 AUG e3.0 el. 2 e5.8 ell el. 7 el. 2 1.1 1.0 2.4 18 1.6 5.1 2.4 1.2 1.1 7.6 14 16 1.9 1.4 1.2 e37 e7.4 e6.8 e6.4 e4.3 e4.9 e3.3 e2.1 el. 9 el. 9 175.9 5.67 37 1.0 349 5.62 6.48 SEP el. 9 e2.5 e2.3 el. 9 el. 6 el. 3 el. 5 el. 4 e3.6 e2.3 el. 3 el. 7 e4.0 elO e3.5 e2.0 el. 4 el. 5 el. 5 el. 3 e4.5 e7.0 e5.6 4.8 11 e!6 e3.8 e2.3 e2.0 e2.1 107.6 3.59 16 1.3 213 3.55 3.96 , BY WATER YEAR (WY) 4.54 9.76 1987 .90 1997 FOR 1997 1892 5 64 614 7 3750 5 69 13 2 7.56 14.3 1992 2.51 1996 WATER YEAR .49 .18 Nov 12 . 31 May 3 .32 Apr 30 Jul 21 .39 Jul 21 .31 May 1 .13 .70 .0 .75 5.93 13.7 1987 .98 1985 6.45 12.7 1983 2.33 1991 WATER 6 9 3 425 4020 11 4730 6 87 16 2 6.66 14.2 1988 .50 1993 YEARS 1983 .52 .32 .91 .00 .01 .35 .00 .46 .77 .6 .46 Sep Aug Mar Sep Sep Aug 7.04 21.9 1996 2.45 1986 - 1997 1988 1994 10 1996 14 1993 31 1994 10 1996 10 1996 13 1993 e Estimated 310 RIO ESPIRITU SANTO BASIN 50063800 RIO ESPIRITU SANTO NEAR RIO ORANDE, PR LOCATION.—Lat 18°21'37", long 65°48'49", Hydrologic Unit 21010005, at downstream side of bridge on Highway 966, 0.1 mi (0.2 km) upstream from Quebrada Jimenez, and 1.9 mi (3.1 km) southeast of Rio Orande. DRAINAGE AREA.—8.62 mi 2 (22.33 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February 1959 to April 1963 (annual low-flow and occasional measurements only), August 1966 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 40 ft (12 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR MAY JUN JUL AUG SEP 1 49 61 2 54 124 3 77 48 4 51 76 5 38 163 6 34 84 7 34 400 8 34 92 9 26 86 10 45 60 11 37 146 12 29 694 13 41 383 14 38 122 15 26 67 16 23 48 17 20 168 18 19 121 19 18 226 20 18 57 21 19 41 22 18 310 23 19 85 24 25 656 25 30 102 26 206 59 27 69 43 28 138 156 29 e!20 73 30 e32 278 31 e27 TOTAL 1414 5029 MEAN 45.6 168 MAX 206 694 MIN 18 41 AC-FT 2800 9980 CFSM 5.29 19.4 IN. 6.10 21.70 85 79 42 42 48 47 41 37 35 35 212 88 43 39 41 98 49 36 29 28 28 30 30 49 48 110 145 222 347 124 90 2377 76.7 347 28 4710 8.90 10.26 63 86 e60 e45 e70 e60 e52 e45 e52 e42 e38 e34 e32 e31 e29 e29 28 26 30 104 377 499 405 500 156 148 60 91 113 59 66 3430 111 500 26 6800 12.8 14.80 270 142 82 85 111 88 61 50 213 60 54 121 153 57 46 40 36 36 62 37 252 208 47 53 44 56 35 28 —— —— 2527 90.3 270 28 5010 10.5 10.91 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1966 MEAN 59.7 85.7 MAX 202 196 (WY) 1971 1985 MZN 12.3 29.1 (WY) 1969 1982 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 72.3 179 1971 16.8 1994 FOR 55.1 119 1969 18.5 1977 51.2 117 1982 10.8 1983 27 36 55 65 102 49 35 87 83 39 32 35 35 30 37 41 36 35 34 31 29 28 25 21 20 21 21 21 24 23 21 1178 38.0 102 20 2340 4.41 5.08 - 1997 38.6 153 1990 9.53 1996 1996 CALENDAR YEAR 27444.4 75.0 2000 3.6 5.5 54440 8.70 118.44 161 37 10 Sep 10 Apr 2 Mar 20 20 19 56 33 56 26 23 22 21 20 19 18 18 18 15 14 14 14 16 26 16 16 20 20 19 17 18 20 20 19 —— 653 21.8 56 14 1300 2.53 2.82 18 17 17 20 21 19 141 186 93 53 77 76 66 49 19 32 63 34 25 22 41 24 22 26 21 22 26 56 72 65 32 1455 46.9 186 17 2890 5.44 6.28 51 410 102 24 15 13 12 12 11 11 12 12 13 33 14 12 11 11 12 19 19 14 75 69 51 32 20 14 12 12 —— 1128 37.6 410 11 2240 4.36 4.87 12 12 12 13 15 20 22 26 30 33 23 22 26 34 25 58 55 31 66 197 330 105 112 38 62 50 33 37 33 66 86 1684 54.3 330 12 3340 6.30 7.27 36 30 29 48 28 21 20 20 41 148 44 55 59 32 30 75 102 236 88 73 71 923 103 140 105 49 35 27 23 24 31 2746 88.6 923 20 5450 10.3 11.85 39 48 34 48 30 23 24 28 97 38 24 33 197 259 223 61 38 93 55 31 e80 e!28 e82 e61 e48 e350 elOO e48 e42 e45 2407 80.2 350 23 4770 9.31 10.39 , BY WATER YEAR (WY) 43.1 119 1981 6.27 1984 FOR 1997 26028 71 923 11 12 4700 8 51630 8 112 147 39 18 66.1 185 1979 14.9 1973 WATER YEAR .3 Aug 22 Jun 9 Jun 6 Aug 22 .33 Aug 22 .27 .33 45.8 120 1970 10.0 1975 52.2 114 1983 11.1 1975 WATER 57 98 21 2600 3 4 21200 16 41710 6 90 123 26 10 60.4 123 1988 18.5 1994 YEARS 1966 .6 .6 .6 Dec .6 Apr .4 Jun Aug . 62 Aug .68 .74 59.6 191 1989 17.7 1971 - 1997 1979 1994 7 1987 2 1996 30 1975 13 1990 13 1990 e Estimated RIO ESPIRITU SANTO BASIN 50063800 RIO ESPIRITU SANTO NEAR RIO GRANDE, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1958, 1961-66, 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 311 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 31... 1200 26 116 6.2 26.5 2.0 6.7 85 <10 4300 290 FEB 1997 19... 0900 47 107 6.5 21.5 3.2 8.6 96 <10 2600 K1700 JUN 06... 0940 13 92 6.8 26.5 2.8 7.8 97 <10 330 510 SEP 10... 1020 27 68 6.5 25.0 2.6 7.7 94 <10 K1500 2200 ALKA- DATE OCT 1996 31... FEB 1997 19... JUN 06... SEP 10... DATE OCT 1996 31... FEB 1997 19... JUN 06... SEP 10... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 35 — 210 44 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- 0.13 <0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 7.9 — 66 9.5 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 19 -- 38 23 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 3.7 — 11 4.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 71 — 236 100 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 7.9 __ 38 9.6 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.98 — 8.41 7.29 SODIUM AD- SORP- TION RATIO (00931) 0.6 __ 1 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 1 <1 7 7 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 0.50 — 3.5 5.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.080 0.090 0.040 0.090 LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 39 34 31 20 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 <0.010 <0.010 <0.010 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.00 0.090 0.050 0.090 SULFATE DIS- SOLVED (MG/L AS 304) (00945) 1.8 — 11 1.9 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.010 0.020 0.020 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 9.1 -- 50 15 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.36 <0.20 <0.20 0.23 DATE OCT 1996 31... FEB 1997 19... JUN 06... SEP 10... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.40 <0.20 <0.20 0.24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.28 0.22 0.22 0.33 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 1.3 0.97 0.97 1.5 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 <0.020 <0.020 <0.020 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- 20 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K - non-ideal count 312 RIO ESPIRITTJ SANTO BASIN 50063800 RIO ESPIRITtJ SANTO NEAR RIO GRANDE, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1958, 1961-66, 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 31... FEE 1997 19... JUN 06... SEP 10... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 260 120 <1 <1 10 10 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.02 <0.02 RIO ESFZRITU SANTO BASIN 50064200 RIO GRANDE NEAR EL VERDE, PR LOCATION.—Lat 18°20'42", long 65°50'30", Hydrologic Unit 21010005, on left bank 250 ft (7.6 m) upstream side of bridge at Hwy 960, 0.05 mi (0.08 km) southwest of junction of Highways 956 and 960, 1.1 mi (1.8 km) west of El Verde, and 2.7 mi (4.3 km) south of Rio Grande. DRAINAGE AREA.--7.31 mi 2 (18.93 km*). PERIOD OP RECORD.--May 1967 to December 1970, January 1972 to September 1982, August 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 131 ft (40 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, wich are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 313 DAY OCT NOV JAN APR JUL AUG SEP 1 12 26 2 13 62 3 25 17 4 14 21 5 9.6 49 6 12 36 7 23 140 8 15 38 9 11 20 10 33 14 11 20 44 12 8.6 e292 13 10 138 14 7.7 64 15 6.8 41 16 6.2 26 17 5.5 72 18 5.0 56 19 5.0 37 20 4.5 25 21 4.3 26 22 4.1 155 23 5.4 42 24 4.7 237 25 36 62 26 140 e28 27 41 e21 28 77 e76 29 49 e35 30 13 e!40 31 8.6 TOTAL 630.0 2040 MEAN 20.3 68.0 MAX 140 292 MIN 4.1 14 AC-FT 1250 4050 CFSM 2.78 9.30 IN. 3.21 10.38 STATISTICS OF MONTHLY MEAN MEAN 55.7 67.7 MAX 392 172 (WY) 1971 1970 MIN 8.45 14.3 (WY) 1969 1981 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS e42 e38 e20 e20 19 17 15 14 13 14 185 68 23 17 20 48 24 15 13 12 14 16 13 16 19 37 55 94 134 68 37 1140 36.8 185 12 2260 5.03 5.80 23 25 17 13 20 17 15 13 15 12 11 9.9 9.2 8.8 8.2 7.4 6.8 6.9 7.7 34 170 213 163 192 , 77 65 29 53 43 33 41 1358.9 43.8 213 6.8 2700 6.00 6.92 DATA FOR WATER 47.0 140 1971 13.8 1968 FOR 43.0 151 1969 10.1 1977 96 41 35 34 58 47 25 24 71 28 23 44 95 28 20 17 15 15 49 34 137 76 26 26 24 27 18 15 ... ... —— 1148 41.0 137 15 2280 5.61 5.84 YEARS 1967 31.0 76.4 1969 5.80 1977 15 21 28 38 55 23 17 44 31 18 14 13 14 12 12 13 10 8.5 8.7 8.2 8.2 7.7 7.2 6.8 6.9 7.5 7.3 6.6 7.5 7.2 6.0 482.3 15.6 55 6.0 957 2.13 2.45 - 1997 20.7 54.4 1969 4.50 1977 1996 CALENDAR YEAR 13344. 36. 1100 4. 4. 26470 4. 67. 72 18 6. 8 5 Sep 10 1 Oct 22 7 Oct 18 99 91 2 6.0 13 35 11 21 10 8.1 7.7 7.4 7.1 7.4 7.7 7.2 7.0 6.5 6.0 5.8 5.6 6.7 15 6.3 5.1 4.7 4.7 4.7 4.7 5.0 4.9 4.2 4.0 —— 249.5 8.32 35 4.0 495 1.14 1.27 3.9 4.5 4.1 3.9 3.6 4.1 57 67 46 25 21 21 26 29 11 9.8 28 15 8.5 8.0 9.0 7.8 7.4 7.5 7.2 6.7 42 43 29 40 16 612.0 19.7 67 3.6 1210 2.70 3.11 20 106 72 27 14 13 11 8.9 8.4 7.3 7.0 6.8 6.9 12 7.4 6.6 5.6 e5.6 12 10 67.5 5.6 44 43 622 26 11 7.6 6.4 5.8 546.4 18.2 106 5.6 1080 2.49 2.78 5.2 5.0 4.6 4.5 5.4 7.1 5.8 7.2 7.7 7.8 5.3 4.9 4.6 5.4 10 11 17 14 20 102 129 51 75 26 26 31 19 23 21 32 60 747.5 24.1 129 4.5 1480 3.30 3.80 26 18 30 56 25 18 17 16 53 95 30 25 48 22 20 49 112 162 39 27 24 348 69 66 62 42 48 29 22 19 20 1637 52.8 348 16 3250 7.22 8.33 21 26 25 21 17 16 17 16 39 27 15 20 62 106 41 25 18 19 19 17 53 67 53 41 19 152 36 22 19 20 1049 35.0 152 15 2080 4.78 5.34 , BY WATER YEAR (WY) 26.8 119 1978 6.29 1995 FOR 1997 11640 31 348 3 4 3100 11 3 23090 4 59 68 19 5 50.6 203 1969 10.2 1974 WATER YEAR .6 .9 Aug 22 .6 May 5 .0 Apr 30 Nov 12 .73 Nov 12 .4 May 5 .36 .24 .7 30.8 86.5 1968 6.22 1975 36.7 109 1969 8.66 1994 WATER 40 87 17 3470 2 2 17400 15 1 29040 42.7 90.0 1968 7.39 1991 YEARS 1967 - .1 .1 .3 May 21 .2 Aug 15 .5 Aug 10 Sep 16 .50 Sep 16 .6 Mar 13 48.6 153 1975 12.4 1967 1997 1969 1994 1969 1991 1991 1975 1975 1977 5.48 74 78 17 6 .51 .6 e Estimated 314 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR LOCATION.--Lat 180 19'46", long 65°45'04", Hydrologic Unit 21010005, on left bank, at bridge on Highway 988, 1.4 mi (2.3 km) west of Sabana, 2.0 mi (3.2 km) downstream from Rio da la Mina, and 3.2 mi (5.1 km) southeast of Mameyes. DRAINAGE AREA.--6.88 mi 2 (17.82 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—August 1967 to December 1973, June 1983 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 275 ft (84 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 32 44 2 e36 e57 3 e49 39 4 e43 42 5 e69 87 6 e36 50 7 e31 362 8 e!9 64 9 22 e47 10 e78 e35 11 e26 131 12 19 e326 13 29 e286 14 25 e83 15 22 e70 16 29 e56 17 e28 elOO 18 26 e58 19 e25 109 20 e23 e47 21 e22 e54 22 e23 e62 23 e23 e50 24 e23 e280 25 e26 e62 26 91 e50 27 30 e52 28 163 e66 29 108 e60 30 21 6200 31 32 —— TOTAL 1229 3029 MEAN 39.6 101 MAX 163 362 MIN 19 35 AC -FT 2440 6010 CFSM 5.76 14.7 IN. 6.65 16.38 STATISTICS OF MONTHLY MEAN MEAN 63.5 80.3 MAX 240 191 (WY) 1971 1985 MIN 20.3 36.3 (WY) 1969 1974 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS e90 e60 e41 e39 e34 e32 e32 e29 e27 e30 42 29 23 23 25 39 25 22 21 20 21 21 20 23 23 29 42 46 67 44 41 1060 34.2 90 20 2100 4.97 5.73 30 41 33 30 40 37 32 34 29 27 26 25 24 23 23 22 e26 21 21 35 e90 e!80 e!30 e!40 e60 e66 e37 e56 e50 e40 e42 1470 47.4 180 21 2920 6.89 7.95 elOO e54 e74 e60 e70 e56 e54 e45 e80 e48 e48 e78 e86 e47 e40 34 34 33 45 36 e70 e50 35 36 36 36 32 30 ___ ... —— 1447 51.7 100 30 2870 7.51 7.82 DATA FOR WATER YEARS 1967 58.7 164 1971 16.6 1990 FOR 54.4 105 1969 25.0 1985 42.3 68.0 1988 21.7 1968 29 33 e40 e35 e50 34 31 e44 e41 32 e28 e33 e32 e28 29 29 25 28 26 e26 e30 e27 e26 e26 e28 e30 e45 e48 e60 e32 e31 1036 33.4 60 25 2050 4.86 5.60 - 1997 37.2 79.7 1990 18.1 1968 1996 CALENDAR YEAR 21383 58 2140 12 15 42410 8 115 92 31 17 .4 Sep 10 May 28 May 25 .49 .62 e29 e49 e39 e76 e80 e37 e34 e33 e30 e29 e30 e29 e43 e30 e29 e29 e31 e31 e38 e30 e28 e27 e25 e21 e21 e21 e26 e22 e21 e21 --- 989 33.0 80 21 1960 4.79 5.35 e20 e!9 e!8 e!8 e!7 e!7 e82 131 50 34 72 46 91 44 29 36 55 38 30 31 45 29 50 52 e37 e94 el!9 e44 54 42 44 1488 48.0 131 17 2950 6.98 8.05 56 225 93 45 35 30 26 23 20 18 18 17 23 34 18 16 16 e29 32 67 654 27 86 60 42 46 31 27 25 22 --- 1261 42.0 225 16 2500 6.11 6.82 21 19 19 18 20 21 19 23 28 24 19 20 59 33 24 44 34 24 42 63 213 71 86 32 47 38 25 33 24 68 47 1258 40.6 213 18 2500 5.90 6.80 28 29 39 55 35 33 33 35 40 109 36 37 37 28 29 63 63 70 36 33 30 373 59 66 58 41 41 35 30 29 41 1671 53.9 373 28 3310 7.83 9.04 53 40 34 47 30 27 26 27 62 34 26 31 95 101 135 41 32 54 32 29 43 76 64 46 162 401 60 47 47 45 1947 64.9 401 26 3860 9.43 10.53 , BY WATER YEAR (WY) 39.8 83.1 1973 14.5 1984 FOR 1997 17885 49 401 16 19 11400 10 35470 7 96 82 35 21 64.3 147 1970 18.7 1973 WATER YEAR .0 Sep 26 Jun 16 Apr 30 Sep 26 .65 Sep 26 .12 .70 54.9 112 1970 12.4 1985 49.7 93.4 1969 20.3 1994 WATER 55. 78. 33. 2780 6. 9. 20500 13. 5. 40140 8. 109. 100 33 16 52.6 81.4 1988 20.4 1994 YEARS 1967 4 0 1 Sep 9 Apr 4 Jun Sep 19 Sep 1 Apr 05 43 60.3 166 1989 26.6 1986 - 1997 1971 1994 18 1989 20 1970 12 1985 18 1989 18 1989 8 1970 e Estimated RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA,PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.-- Water years 1992 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1992 to current year. INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler, since 1993. REMARKS:-- Sediment samples were collected by a local observer on a weekly basis and during high flow events. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 484 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, e4,290 tons (e3,891 tonnes) September 10, 1996; Minimum daily mean, 0.03 tons (0.02 tonne) October 05, 1994. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 162 mg/L November 7,1996 - September 26, 1997; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 938 tons (851 tonnes) September 26, 1997; Minimum daily mean, 0.04 tons (0.04 tonne) May 4-6, 1997. 375 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 32 e36 e49 e43 e69 e36 e31 e!9 22 e78 e26 19 29 25 22 29 e28 26 e25 e23 e22 e23 e23 e23 e26 91 30 163 108 21 32 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 32 e36 e49 e43 e69 e36 e31 e!9 22 e78 e26 19 29 25 22 29 e28 26 e25 e23 e22 e23 e23 e23 e26 91 30 163 108 21 32 11 10 16 12 23 15 11 6 7 30 9 7 9 7 7 4 5 12 11 7 4 4 10 15 21 30 9 109 52 18 12 .99 e.98 e3.2 el. 7 e5.5 el. 5 e.99 e.32 .47 ell e.72 .34 1.1 .56 .46 .31 e.35 .84 .72 .42 .27 .21 .62 .94 el. 5 9.4 .82 264 41 1.0 1.1 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) NOVEMBER 44 e57 39 42 87 50 362 64 e47 e35 131 e326 e286 e83 e70 e56 elOO e58 109 e47 e54 e62 eSO e280 e62 eSO e52 e66 e60 e200 ___ 16 17 13 13 27 15 162 24 16 10 44 115 84 19 9 5 14 12 39 32 20 17 17 42 44 15 10 9 16 38 ___ 2.4 e3.3 2.5 1.7 10 2.3 285 4.5 2.1 .99 20 e!76 e!62 e4.5 e2.0 e.91 e3.2 e2.1 20 e5.9 e2.7 e2.7 e2.6 e!9 e20 e2.2 el. 4 el. 5 e2.7 e!4 ___ DECEMBER e90 e60 e41 e39 e34 e32 e32 e29 e27 e30 42 29 23 23 25 39 25 22 21 20 21 21 20 23 23 29 42 46 67 44 41 40 17 11 8 4 1 1 2 4 6 15 10 8 7 8 12 7 4 2 2 2 3 3 6 10 10 24 15 20 13 14 e!6 e3.5 el. 5 .90 .36 .12 .13 .19 .28 .41 1.9 .74 .51 .43 .57 1.4 .46 .23 .13 .12 .13 .15 .16 .36 .65 .91 3.1 2.3 4.4 1.5 1.6 TOTAL 1229 353.33 3029 780.20 1060 45.14 e Estimated 316 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA,PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) JANUARY 30 41 33 30 40 37 32 34 29 27 26 25 24 23 23 22 e26 21 21 35 e90 e!80 e!30 e!40 e60 e66 e37 e56 e50 e40 e42 15 14 7 6 13 12 11 12 17 21 16 10 6 4 3 5 9 14 11 11 55 41 48 66 30 18 17 18 19 14 12 1.2 1.6 .58 .47 1.4 1.2 .92 1.1 1.3 1.5 1.1 .68 .42 .27 .20 .30 e.50 .78 .61 1.1 e8.1 e!4 e20 e24 e7.9 e3.1 e2.3 e2.2 e2.7 el. 6 el. 2 elOO e54 e74 e60 e70 e56 e54 e45 eSO e48 e48 e78 e86 e47 e40 34 34 33 45 36 e70 eSO 35 36 36 36 32 30 —— 35 40 18 19 17 14 12 14 17 16 15 19 24 20 17 14 8 5 12 7 21 15 9 6 4 4 5 5 e7.0 e8.2 e3.1 e3.5 e3.0 e2.4 el. 7 el. 8 e2.8 e2.7 el. 9 e3.3 e5.2 e3.6 e2.0 1.3 .73 .42 1.6 .69 e3.9 e2.0 .88 .61 .42 .41 .39 .39 MEAN DISCHARGE (CFS) 29 33 040 035 050 34 31 044 041 32 028 033 032 028 29 29 25 28 26 026 030 027 026 026 028 030 045 048 060 032 031 MEAN CONCEN- TRATION (MG/L) MARCH 4 13 11 12 13 11 9 14 13 10 9 8 8 7 11 15 9 5 4 5 5 5 6 6 5 4 4 15 17 20 7 SEDIMENT DISCHARGE (TONS/DAY) .35 1.3 el.l el. 2 el. 4 1.0 .80 el. 8 el. 4 .82 0.64 0.72 0.66 0.56 .85 1.2 .62 .37 .29 0.32 .37 .40 .40 .38 .33 .31 .46 el. 8 02.5 02.5 0.61 1470 104.33 1447 65.94 1036 27.46 e Estimated RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 317 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e29 e49 e39 e76 e80 e37 e34 e33 e30 e29 e30 829 e43 e30 829 829 e31 e31 e38 e30 e28 827 e25 e21 821 e21 826 e22 821 821 APRIL 4 9 13 17 16 5 2 1 2 6 14 12 23 10 6 4 3 2 3 5 7 6 4 7 13 23 17 14 12 10 —— MAY 8.31 e.94 el. 6 e2.7 83.4 8.81 8.23 e.ll 8.18 e.45 el.l e.92 82.2 e.99 8.47 8.29 e.22 8.18 e.29 8.48 e.57 e.42 e.31 8.41 e.63 el.l e.90 8.71 e.56 e.47 820 e!9 e!8 e!8 e!7 e!7 e82 131 50 34 72 46 91 44 29 36 55 38 30 31 45 29 50 52 837 894 el!9 844 54 42 44 10 10 4 1 1 1 28 43 16 13 21 13 29 14 10 7 15 4 6 16 14 9 29 15 7 19 17 20 17 14 14 e.45 e.43 8.15 8.04 8.04 8.04 837 37 2.2 1.2 7.6 2.0 14 1.8 .75 .72 2.6 .40 .49 1.4 1.9 .71 6.7 2.3 8.96 84.0 84.9 83.4 3.4 1.7 1.7 56 225 93 45 35 30 26 23 20 18 18 17 23 34 18 16 16 829 32 67 e54 27 86 60 42 46 31 27 25 22 ___ MEAN ___ CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) JUNE 13 88 30 12 5 2 2 2 2 2 2 2 3 10 2 2 3 9 4 19 17 9 26 18 13 15 9 6 4 2 2.1 218 8.1 1.5 .51 .20 .14 .12 .11 .10 .10 .09 .25 1.0 .12 .09 .14 a. 79 .34 6.6 e3.4 .66 12 3.1 1.5 1.9 .79 .46 .26 .14 TOTAL 989 23.95 1488 141.98 1261 264.61 e Estimated 318 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA,PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR MEAN DISCHARGE (CFS) 21 19 19 18 20 21 19 23 28 24 19 20 59 33 24 44 34 24 42 63 213 71 86 32 47 38 25 33 24 68 47 1258 17885 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 2 2 3 5 8 6 2 7 5 2 3 5 16 10 3 14 4 2 8 20 93 23 20 4 12 12 8 20 5 17 14 — .11 .11 .14 .24 .42 .32 .11 .45 .38 .10 .14 .26 4.1 .96 .28 1.7 .40 .13 1.4 4.9 214 5.7 9.0 .34 2.0 1.2 .54 2.3 .33 7.0 1.9 260.96 3613.72 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 28 29 39 55 35 33 33 35 40 109 36 37 37 28 29 63 63 70 36 33 30 373 59 66 58 41 41 35 30 29 41 4 6 12 10 2 2 2 2 4 36 7 5 10 5 2 17 17 22 7 3 2 123 19 20 18 13 12 11 10 9 20 .32 .47 1.3 1.8 .19 .18 .18 .19 .48 15 .68 .74 1.0 .37 .19 4.9 3.1 4.9 .71 .25 .19 307 3.1 5.1 3.0 1.4 1.4 1.0 .79 .68 2.8 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 53 40 34 47 30 27 26 27 62 34 26 31 95 101 135 41 32 54 32 29 43 76 64 46 162 401 60 47 47 45 17 8 3 14 11 10 9 9 19 11 9 10 36 38 42 12 5 16 11 9 12 22 20 7 59 162 9 6 9 9 4.6 .90 .28 1.9 .92 .76 .65 .63 6.5 1.0 .61 .85 36 26 19 1.3 .43 2.6 .92 .72 1.4 7.7 4.6 1.2 118 938 1.7 .74 1.1 1.4 1671 363.41 1947 1182.41 RIO MAMEYES BASIN 50065500 RIO MAMEYES NR SABANA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 319 DATE OCT 1996 28... NOV 13... JUL 1997 21... AUG 22... SEP 13... 26... TIME 2300 0150 0700 1235 2350 1030 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1250 1370 1490 2760 799 5920 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1240 938 1050 683 591 2201 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 4180 3470 4240 5090 1274 35200 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 38 31 21 26 24 20 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 42 43 31 32 34 25 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 51 58 43 43 48 33 DATE OCT 1996 28... NOV 13... JUL 1997 21... AUG 22... SEP 1997 13... 26... SED. SUSP. FALL DIAM. *S FINER THAN .016 MM (70329) 71 71 59 58 65 47 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 83 83 72 71 79 62 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 97 95 88 88 90 81 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 98 98 93 93 95 87 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 98 98 98 95 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 99 99 99 98 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 99 100 99 320 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 10... NOV 07... 07... 07... 13... 22. .. MAY 1997 23... JUN 02... 02... JUL 21... 21... AUG 22... 22... 22. .. 22... 31... SEP 1997 13... 25... 26... TIME 1656 0240 0300 1445 0225 1558 1540 1630 1655 0640 0725 1255 1325 1545 1623 1255 2350 1516 0836 DIS- CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 234 1060 965 811 1150 62 62 1830 1570 1750 1030 1740 873 1060 861 54 799 1310 990 SEDI- MENT, SUS- PENDED (MG/L) (80154) 240 1120 600 454 591 233 61 815 546 1140 533 443 262 168 201 36 591 811 470 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 152 3200 1560 994 1830 39 10 4030 2310 5390 1480 2070 617 481 467 5.2 1270 2870 1260 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 89 94 92 92 95 93 97 78 83 76 87 92 92 87 93 94 90 92 90 321 RIO SABANA BASIN 50067000 RIO SABANA AT SABANA, PR LOCATION.--Lat 18°19'52", long 65°43'52", Hydrologic Unit 21010005, on right bank along Highway 988, 0.3 mi (0.5 km) north of junction of Highways 988 and 983 in Sabana, and 3.3 mi (5.3 km) south of Luquillo. DRAINAGE AREA.--3.96 mi' (10.26 kma ). PERIOD OF RECORD.—October 1979 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 260 ft (80 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Low-flow affected by Puerto Rico Aqueduct and Sewer Authority Water Intake 1.0 mi (1.6 km) upstream, and purification plant 0.2 mi (0.32 km), Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER DAY OCT NOV 1 20 28 2 18 30 3 16 28 4 32 29 5 37 50 6 20 41 7 37 350 8 20 42 9 18 31 10 38 16 11 23 18 12 17 90 13 19 147 14 21 30 15 20 17 16 18 12 17 16 12 18 17 20 19 18 56 20 16 20 21 15 59 22 15 87 23 18 43 24 15 180 25 14 32 26 21 22 27 17 20 28 69 34 29 79 25 30 21 84 31 19 TOTAL 744 1653 MEAN 24.0 55.1 MAX 79 350 MIN 14 12 AC-FT 1480 3280 CFSM 6.06 13.9 IN. 6.99 15.53 STATISTICS OF MONTHLY MEAN MEAN 22.4 32.6 MAX 66.4 79.7 (WY) 1986 1988 MIN 6.48 8.15 (WY) 1983 1981 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 34 31 25 22 19 19 18 17 16 16 18 16 15 14 16 43 17 13 13 12 13 13 12 12 12 12 26 31 125 40 24 714 23.0 125 12 1420 5.82 6.71 JAN 16 16 14 16 42 23 16 33 18 14 14 13 12 11 10 11 11 11 10 13 32 130 92 105 32 15 11 13 15 13 29 811 26.2 130 10 1610 6.61 7.62 SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBE) DAILY MEAN VALUES FEB 125 73 19 38 35 15 14 11 38 12 15 25 20 10 8.7 8.3 8.8 8.7 13 11 52 28 11 9.6 8.9 8.1 7.7 17—— —— —— 650.8 23.2 125 7.7 1290 5.87 6.11 DATA FOR WATER YEARS 1980 25.1 64.1 1982 3.92 1990 FOR 15.6 48.5 1996 6.12 1986 13.0 23.2 1997 2.94 1983 MAR 7.2 8.0 12 14 19 12 11 18 19 17 15 16 15 13 12 12 11 13 11 11 12 9.6 8.6 8.0 8.1 8.4 8.3 14 13 9.3 8.0 373.5 12.0 19 7.2 741 3.04 3.51 - 1997 11.3 36.0 1987 2.71 1994 1996 CALENDAR YEAR 11581.2 31.6 1100 2.2 2.8 22970 7.99 108.79 59 18 3.9 Sep 10 May 29 Mar 20 APR 6.6 21 23 12 9.4 6.3 5.5 5.2 5.1 4.8 4.6 4.9 4.4 4.5 4.1 3.7 3.9 4.4 4.5 5.3 5.5 5.5 .4 .3 .2 .1 .9 .1 .4 .6 —— 190.2 6.34 23 3.7 377 1.60 1.79 MAY .7 .4 .4 .0 .9 .1 .8 13 6.8 4.7 22 13 16 8.2 3.9 3.6 4.5 3.8 2.7 3.0 3.4 2.9 6.4 17 9.6 147 124 18 8.4 6.0 7.4 485.6 15.7 147 2.7 963 3.96 4.56 JUN 5.4 4.4 10 4.8 3.0 2.3 e2.1 e2.6 e2.1 el. 8 el. 7 e3.7 eS.l e3.7 el. 9 el. 7 el. 8 e3.6 e4.0 e9.4 e2.7 el. 8 e9.0 eS.O e2.0 3.6 2.8 3.0 2.2 2.1 —— 109.3 3.64 10 1.7 217 .92 1.03 R 1997 JUL 1.6 1.9 2.0 2.1 2.1 2.5 2.5 3.3 4.2 5.6 4.0 3.8 93 24 4.9 6.6 5.0 3.6 4.0 7.4 166 54 34 9.3 14 12 6.3 10 6.1 27 20 542.8 17.5 166 1.6 1080 4.42 5.10 AUG 6.5 6.0 8.1 5.7 4.5 3.8 3.9 3.7 4.6 12 5.1 4.1 3.1 3.0 3.4 4.1 7.9 8.4 4.3 3.2 3.5 124 11 22 17 6.2 7.8 6.6 11 9.2 29 352.7 11.4 124 3.0 700 2.87 3.31 SEP 34 14 7.9 9.6 7.0 6.4 6.6 5.9 17 9.3 5.0 9.1 23 45 63 13 8.0 11 7.4 6.7 8.8 30 16 15 166 e400 e21 e9.2 eS.O e52 1034.9 34.5 400 5.0 2050 8.71 9.72 , BY WATER YEAR (WY) 11.3 33.5 1990 2.20 1984 FOR 1997 7661 21 400 1 2 2960 14 15200 5 71 38 12 3 31.2 63.9 1982 4.65 1994 WATER YEAR .8 .0 Sep 26 .6 Jul 1 .0 Jun 29 Sep 26 .15 Sep 26 .30 .97 .6 20.4 50.6 1987 3.64 1997 16.8 36.0 1996 5.84 1986 WATER 20 31 7 1100 1 9600 19 14600 5 69 38 8 2 17.9 39.9 1995 3.09 1994 YEARS 1980 .2 .9 .85 .96 .0 .74 .86 .09 .17 .8 .7 Sep Apr Apr Jan Jan Apr 23.9 74.2 1996 7.23 1987 - 1997 1996 1994 10 1996 10 1983 6 1983 5 1992 5 1992 17 1983 e Estimated 322 RIO FAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, PR LOCATION.--Lat 18°16'21", long 65°43'18", Bydrologic Unit 21010005, on right bank, 4.1 mi (6.6 km) from Plaza de Naguabo, 0.5 mi (0.8 km) northeast from Escuela Sonadora, 1.5 mi (2.4 km) southwest of Colonia Paraiso, and 2.5 mi (4.0 km) norht from Escuela Segunda Unidad Mariana. DRAINAGE AREA.—3.69 mi 2 (9.56 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—Oct. 1, 1995 to Nov. 8, 1995 (estimated discharge). Nov. 9, 1995 to current year. GAGE.—Water-stage recorder. Datum of gage is 328 ft (100 m) above mean sea level, from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV 1 e7.2 ell 2 e!2 e25 3 e9.2 e54 4 el? e32 5 e!9 e45 6 ell ellO 7 e9.4 e28 8 e20 e23 9 e20 e!9 10 e!9 e!7 11 e!8 e!4 12 e!7 e!2 13 e!70 e30 14 e39 e!4 15 e32 ell 16 e!6 e21 17 e!7 e!4 18 ell elO 19 ell e9.2 20 e9.0 e8.5 21 68.5 8.5 22 e7.3 8.3 23 e25 8.0 24 e47 8.8 25 e60 9.1 26 e42 13 27 e!3 8.3 28 ell 8.9 29 e9.0 11 30 e7.4 10 31 e9.4 TOTAL 723.4 601.6 MEAN 23.3 20.1 MAX 170 110 MIN 7.2 8.0 AC-FT 1430 1190 CFSM 6.32 5.43 IN. 7.29 6.06 DEC 7.9 7.6 7.7 7.5 7.1 8.0 7.2 8.3 11 16 13 17 58 57 18 25 107 172 60 68 25 21 19 18 17 15 15 24 15 14 13 879.3 28.4 172 7.1 1740 7.69 8.86 STATISTICS OF MONTHLY MEAN DATA MEAN 23.3 20.1 MAX 23.3 20.1 (WY) 1996 1996 MIN 23.3 20.1 (WY) 1996 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 28.4 28.4 1996 28.4 1996 JAN 13 13 14 15 13 26 16 56 18 14 113 59 56 453 106 40 27 34 45 75 37 27 21 23 26 23 49 71 27 19 18 1547 49.9 453 13 3070 13.5 15.60 FOR WATER 49.9 49.9 1996 49.9 1996 FEB MAR 18 10 18 9.9 18 10 20 11 17 33 19 15 29 14 17 14 29 16 18 15 18 14 15 12 28 11 16 10 20 12 17 IS 15 11 14 12 21 11 14 10 13 10 13 9.8 11 9.7 45 9.7 15 9.7 13 9.8 12 9.8 12 15 11 15 13 —— 12 526 389.4 18.1 12.6 45 33 11 9.7 1040 772 4.92 3.40 5.30 3.93 YEARS 1996 - 1996 18.1 12.6 18.1 12.6 1996 1996 18.1 12.6 1996 1996 APR 9.7 9.5 9.2 13 18 11 9.5 9.2 9.2 9.0 8.9 39 19 11 12 12 9.8 16 16 10 9.6 12 25 18 12 12 12 23 16 19—— 419.6 14.0 39 8.9 832 3.79 4.23 , BY WATER 14.0 14.0 1996 14.0 1996 MAY 13 12 11 11 10 11 72 69 42 31 19 18 332 42 22 16 15 13 12 11 13 14 17 15 11 10 11 10 11 19 24 937 30.2 332 10 1860 8.19 9.45 YEAR (WY) 30.2 30.2 1996 30.2 1996 JUN 26 48 19 71 53 74 44 23 23 21 46 155 31 43 128 105 52 57 e55 e43 e43 e47 e46 e35 e30 e26 44 62 31 28 --- 1509 50.3 155 19 2990 13.6 15.21 50.3 50.3 1996 50.3 1996 JUL 26 25 32 25 25 26 25 332 65 32 26 38 35 229 66 29 24 21 e!7 e36 e25 e!9 e!6 e!5 e!6 e28 e!4 e!3 e!4 ell elO 1315 42.4 332 10 2610 11.5 13.26 42.4 42.4 1996 42.4 1996 AUG e!3 e!7 e21 e24 e!5 e!3 e!2 elO e!7 e!6 ell e!5 eSO e220 e90 elSO e76 e41 e34 e20 e!7 e!5 e28 e!20 e90 e33 e!7 e!9 e!5 e!4 e!2 1275 41.1 220 10 2530 11.1 12.85 41.1 41.1 1996 41.1 1996 SEP e29 e!3 elO e24 e64 e27 e!5 e35 e400 e!700 e260 e90 e98 e!30 e!40 e92 e40 e46 e41 54 49 32 32 29 27 25 26 29 25 35 — - 3617 121 1700 10 7170 32.7 36.46 121 121 1996 121 1996 FOR 1996 WATER YEAR 13739.3 37.5 1700 7.1 7.6 5110 10.72 7.0 27250 10.2 138.51 64 18 9.7 Sep 10 Dec 5 Dec 1 Sep 10 Sep 10 Dec 7 e Estimated RIO PAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, PR--Continued DISCHARGEE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 323 OCT NOV DEC JAN JUN JUL AUO SEP 1 23 23 2 24 22 3 19 28 4 19 23 5 26 20 6 19 19 7 24 164 8 17 32 9 17 67 10 36 39 11 16 69 12 14 172 13 13 87 14 13 72 15 15 33 16 11 27 17 11 43 18 17 31 19 19 79 20 18 33 21 15 99 22 14 35 23 17 24 24 15 191 25 14 20 26 27 15 27 19 20 28 56 42 29 50 26 30 17 82 31 16 —— TOTAL 631 1637 MEAN 20.4 54.6 MAX 56 191 MIN 11 15 AC-PT 1250 3250 CFSM 5 . 52 14 . 8 IN. 6.36 16.50 STATISTICS OF MONTHLY MEAN MEAN 21.8 37.3 MAX 23.3 54.6 (WY) 1996 1997 MIN 20.4 20.1 (WY) 1997 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 39 22 17 15 14 15 15 15 15 16 45 14 14 14 18 45 16 14 13 13 14 14 13 15 17 17 53 68 114 57 38 809 26.1 114 13 1600 7.07 8.16 DATA 27.2 28.4 1996 26.1 1997 21 17 16 24 40 19 19 49 20 15 14 18 14 14 14 13 14 14 17 42 89 216 135 153 e33 e28 e20 e28 e27 el9 e23 1185 38.2 216 13 2350 10.4 11.95 FOR WATER 44.1 49.9 1996 38.2 1997 e200 e28 e68 e29 e31 e!8 e!9 e!4 e43 e!7 e!5 e82 e58 e27 e!6 15 16 16 23 21 47 28 19 18 19 19 18 16 —— ___ —— 940 33.6 200 14 1860 9.10 9.48 YEARS 1996 25.7 33.6 1997 18.1 1996 16 18 23 21 27 16 16 24 19 15 15 15 15 13 13 13 12 11 11 10 13 9.9 9.8 9.5 9.5 9.5 9.8 19 16 11 11 451.0 14.5 27 9.5 895 3.94 4.55 - 1997 13.6 14.5 1997 12.6 1996 FOR 1996 CALENDAR YEAR 14612. 39. 1700 8. 9. 28980 10. 147. 71 19 11 0 9 Sep 10 9 Apr 11 8 Mar 21 8 31 10 35 18 16 19 11 10 10 9.6 9.4 9.0 8.6 8.7 8.5 8.2 7.7 7.7 7.4 7.6 7.7 7.0 7.0 7.0 7.3 7.3 7.3 7.7 7.6 7.6 7.6 —— 302.5 10.1 35 7.0 600 2.73 3.05 7.4 7.3 7.3 7.6 7.7 7.8 21 26 11 10 13 11 28 13 10 10 14 10 9.5 11 13 10 10 10 9.8 27 22 14 15 13 14 400.4 12.9 28 7.3 794 3.50 4.04 15 e50 e!8 12 11 9.7 9.4 10 9.0 8.7 8.7 8.5 11 10 8.1 7.5 8.0 elO 12 e20 ell 8.6 18 12 9.7 15 9.4 8.6 8.4 8.4 —— 365.7 12.2 50 7.5 725 3.30 3.69 8.4 8.2 8.0 8.0 7.9 7.6 7.9 9.1 8.9 8.1 7.8 8.6 11 9.1 8.1 9.4 9.6 9.7 12 17 99 29 29 15 15 19 13 17 13 18 16 467.4 15.1 99 7.6 927 4.09 4.71 13 13 13 17 13 12 12 12 15 45 14 13 14 16 16 31 23 24 15 14 13 61 20 25 20 18 16 15 14 13 19 579 18.7 61 12 1150 5.06 5.84 28 16 15 13 12 12 11 19 17 13 12 14 21 22 36 16 14 17 14 14 20 20 21 17 34 e430 e!9 16 15 28 —— 956 31.9 430 11 1900 8.64 9.64 , BY WATER YEAR (WY) 12.0 14.0 1996 10.1 1997 FOR 1997 8724 23 430 7 7 1580 6 7 17300 6 87 42 15 8 21.6 30.2 1996 12.9 1997 WATER YEAR .0 .9 Sep 26 .0 Apr 21 .2 Apr 20 Sep 26 .49 Sep 26 .0 Apr 20 .48 .95 .4 31.2 50.3 1996 12.2 1997 28.7 42.4 1996 15.1 1997 WATER 30 37 23 1700 7 7 5110 10 7 22260 8 113 54 16 9 29.9 41.1 1996 18.7 1997 YEARS 1996 - .7 .5 .9 Sep 10 .0 Apr 21 .2 Apr 20 Sep 10 .72 Sep 10 .0 Dec 7 .33 .15 .1 76.2 121 1996 31.9 1997 1997 1996 1997 1996 1997 1997 1996 1996 1995 e Estimated 324 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, PR—Continued HATER-QUALITY RECORDS PERIOD OF RECORD.—Hater years 1996 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1995 to current year . INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1995. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 477 mg/L September 26, 1997; Minimum daily mean, 1 mg/L several days, 1996-97. SEDIMENT LOADS: Maximum daily mean, 1,540 tons (1,4000 tonnes) January 14, 1996; Minimum daily mean, 0.01 tons (0.01 tonnes)several days, 1996-97. EXTREMES FOR HATER YEARS 1996-1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 366 mg/L May 13, 1996; minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 1,540 tons (1,400 tonnes) January 14, 1996; minimum daily mean 0.02 tons (0.02 tonnes) several days. SEDIMENT CONCENTRATION: Maximum daily mean, 477 mg/L September 26, 1997; minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 719 tons (652 tonnes) September 26, 1997; minimum daily mean 0.02 tons (0.02 tonnes) Jseveral days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) e7.2 e!2 e9.2 e!7 e!9 ell e9.4 e20 e20 e!9 e!8 e!7 e!70 e39 e32 e!6 e!7 ell ell e9.0 e8.5 e7.3 e25 e47 e60 e42 e!3 ell e9.0 e7.4 e9.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 2 1 2 3 3 1 2 4 4 3 3 3 25 8 5 3 3 2 2 1 1 1 3 11 14 5 2 1 1 1 1 e.04 e.04 e.05 e.12 e.14 e.06 e.06 e.15 e.19 e.18 e.16 e.14 e4.5 el. 9 e.46 e.19 e.12 e.08 e.05 e.04 e.03 e.02 e.12 el.O e2.0 .71 .12 .04 .03 .02 .03 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 723.4 12.79 ell e25 e54 e32 e45 ellO e28 e23 e!9 e!7 e!4 e!2 e30 e!4 ell e21 e!4 elO e9.2 e8.5 8.5 8.3 8.0 8.8 9.1 13 8.3 8.9 11 10 601.6 3 4 9 8 10 20 5 4 3 3 2 2 4 2 2 3 1 1 1 1 1 1 1 1 1 2 1 1 1 1 e.07 e.19 e.98 e.88 el.O e3.7 e.83 e.26 e.18 e.14 e.10 e.08 e.19 e.ll e.07 e.12 e.07 e.03 e.03 e.02 .02 .02 .02 .02 .03 .10 .02 .03 .04 .03 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 9.38 7.9 7.6 7.7 7.5 7.1 8.0 7.2 8.3 11 16 13 17 58 57 18 25 107 172 60 68 25 21 19 18 17 15 15 24 15 14 13 879.3 1 1 1 1 2 2 2 2 2 3 2 3 24 9 4 3 43 59 17 25 1 1 1 1 1 1 1 6 6 11 3 .03 .03 .03 .03 .03 .04 .03 .04 .06 .14 .08 .26 6.6 1.8 .20 .27 64 47 3.9 12 .08 .06 .05 .05 .05 .04 .04 .46 .25 .42 .12 138.19 e Estimated RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 325 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 13 13 14 15 13 26 16 56 18 14 113 59 56 453 106 40 27 34 45 75 37 27 21 23 26 23 49 71 27 19 18 1 1 1 2 2 7 4 24 2 1 42 16 18 282 28 2 2 5 10 23 8 2 1 1 5 2 14 19 29 33 33 .04 .04 .05 .10 .07 .65 .66 7.4 .12 .05 28 3.5 4.7 1540 11 .25 .15 .57 1.6 6.7 .90 .15 .07 .06 .39 .14 2.2 4.1 2.1 1.8 1.6 18 18 18 20 17 19 29 17 29 18 18 15 28 16 20 17 15 14 21 14 1? 13 11 45 15 13 12 12 11 ___ ___ MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 26 11 5 3 2 3 7 2 7 4 2 2 9 5 5 3 12 17 8 8 7 4 2 13 5 4 10 18 13 1.2 .54 .24 .20 .07 .15 .71 .10 .79 .22 .10 .09 1.9 .22 .29 .15 .48 .64 .53 .29 .24 .13 .06 4.4 .19 .14 .32 .55 .40 MEAN DISCHARGE (CFS) 10 9.9 10 11 33 15 14 14 16 15 14 12 11 10 12 15 11 12 11 10 10 9.8 9.7 9.7 9.7 9.8 9.8 15 15 13 12 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 9 5 3 2 9 4 2 3 8 2 1 3 4 3 2 1 1 2 8 18 6 2 2 2 2 4 5 5 4 3 2 .25 .14 .09 .06 .97 .15 .07 .18 .41 .10 .05 .09 .12 .07 .05 .04 .03 .05 .23 .49 .16 .06 .05 .05 .06 .10 .14 .25 .18 .12 .08 TOTAL 1547 1619.16 526 15.34 389.4 4.89 326 RIO PAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPT! 1996 DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.7 9.5 9.2 13 18 11 9.5 9.2 9.2 9.0 8.9 39 19 11 12 12 9.8 16 16 10 9.6 12 25 18 12 12 12 23 16 19 1 2 2 2 4 2 1 1 2 2 1 9 4 2 1 1 1 3 2 1 1 1 5 3 2 1 1 5 1 1 .03 .04 .04 .11 .22 .06 .03 .03 .04 .05 .03 1.4 .25 .05 .03 .03 .03 .20 .09 .03 .03 .05 .54 .19 .06 .04 .04 .59 .06 .05 13 12 11 11 10 11 72 69 42 31 19 18 332 42 22 16 15 13 12 11 13 14 17 15 11 10 11 10 11 19 24 1 1 1 1 1 1 30 30 2 6 1 1 366 12 2 1 1 1 1 1 2 2 3 1 1 1 1 1 1 4 4 .04 .03 .03 .03 .03 .03 28 29 .30 .57 .06 .05 1500 1.7 .12 .06 .04 .03 .03 .03 .06 .07 .14 .05 .03 .03 .03 .03 .03 .51 .27 26 48 19 71 53 74 44 23 23 21 46 155 31 43 128 105 52 57 e55 e43 e43 e47 e46 e35 e30 e26 44 62 31 28 9 14 4 24 18 27 4 1 3 1 12 43 3 10 53 41 8 13 2 2 1 1 1 1 1 1 5 17 3 2 2.1 5.6 .23 16 13 16 .77 .06 .23 .07 4.3 39 .22 4.0 41 19 1.1 2.4 1.33 1.19 .14 .12 .13 .11 .09 e.08 .66 5.0 .26 .15 419.6 4.44 937 1561.43 1509 172.34 e Estimated 327 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 26 25 32 25 25 26 25 332 65 32 26 38 35 229 66 29 24 21 a!7 a36 a25 a!9 a!6 a!5 al6 a28 a!4 e!3 a!4 all alO JULY 2 2 2 2 3 4 5 219 13 2 1 9 25 141 22 3 1 2 2 1 1 1 2 3 3 2 2 1 1 1 2 TOTAL 1315 —— YEAR a 13739.3 Estimated .14 .14 .17 .14 .18 .26 .34 639 3.4 .19 .08 1.9 2.4 227 5.1 .23 .09 .10 .07 .07 .08 .06 .08 .14 .13 .12 .09 .05 .04 .04 .05 881.88 4706.69 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST •13 •17 a21 •24 •15 •13 a!2 •10 •17 •16 •11 a!5 •50 a220 •90 •180 a? 6 •41 •34 •20 a!7 •15 •28 •120 •90 a33 •17 •19 •15 •14 •12 1275 2 2 2 2 2 2 2 2 2 2 1 1 2 a •: 4 •] 2 2 2 2 2 2 2 11 2 1 1 1 1 2 3 4 .06 .08 .10 .12 .10 .08 .07 .06 .07 .07 .05 .04 .17 2.2 L.6 .80 .65 .30 .20 .14 .10 .09 .58 .36 .34 .15 .06 .05 .08 .13 .14 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 9.04 •29 •13 •10 •24 •64 •27 •15 •35 •400 •1700 •260 •90 •98 •130 •140 •92 •40 •46 •41 54 49 32 32 29 27 25 26 29 25 35 3617 4 4 4 5 11 8 5 5 8 48 40 3 3 7 8 6 5 4 2 15 12 5 3 3 2 2 1 1 1 9 • .21 • .21 • .13 • .21 •1.4 •1.0 • .27 • .35 •3.3 •167 •86 •1.3 • .64 a2.2 •2.7 •1.9 • .82 a.44 • .28 2.9 2.1 .48 .29 .20 .15 .11 .09 .08 .07 .98 277.81 328 RIO PAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 23 24 19 19 26 19 24 17 17 36 16 14 13 13 15 11 11 17 19 18 15 14 17 15 14 27 19 56 50 17 16 19 20 16 8 9 10 8 9 10 10 6 2 1 2 3 2 1 12 64 14 2 1 1 1 1 6 5 30 19 2 1 1.2 1.3 .85 .42 .92 .55 .56 .42 .44 1.1 .26 .06 .05 .08 .14 .07 .04 1.7 3.4 .68 .07 .04 .05 .04 .04 .56 .25 27 5.8 .09 .06 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 23 22 28 23 20 19 164 32 67 39 69 172 87 72 33 27 43 31 79 33 99 35 24 191 20 15 20 42 26 82 9 12 13 9 6 4 108 8 27 14 24 74 48 3 2 3 14 16 21 16 67 10 7 122 7 4 5 14 8 17 .55 .74 1.1 .55 .33 .21 101 .75 7.1 2.1 5.4 45 15 .58 .18 .27 4.3 2.0 7.7 2.2 55 1.8 2.0 111 .47 .18 .25 2.7 .58 6.4 MEAN MEAN CONCEN- SEDIMENT DISCBARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 39 22 17 15 14 15 15 15 15 16 45 14 14 14 18 45 16 14 13 13 14 14 13 15 17 17 53 68 114 57 38 14 7 2 2 4 7 7 5 3 3 19 4 2 1 4 18 3 1 1 1 1 3 6 4 2 3 17 11 33 22 12 2.9 .49 .09 .08 .15 .30 .28 .19 .13 .12 2.8 .16 .06 .04 .62 2.8 .14 .04 .04 .04 .04 .10 .23 .16 .09 .17 2.9 4.7 19 4.0 1.4 TOTAL 631 48.24 1637 377.44 809 44.26 329 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 21 17 16 24 40 19 19 49 20 15 14 18 14 14 14 13 14 14 17 42 89 216 135 153 e33 e28 e20 e28 e27 e!9 e23 9 3 2 10 17 4 3 17 4 3 4 5 2 1 1 2 3 4 11 17 58 129 67 48 43 9 2 2 3 3 2 .52 .15 .10 1.4 2.4 .19 .15 4.4 .21 .11 .14 .23 .08 .04 .05 .08 .13 .16 .69 2.6 17 200 28 22 e!6 el. 4 e.16 e.16 e.21 e.16 e.13 FEBRUARY e200 e28 e68 e29 e31 e!8 e!9 e!4 e43 e!7 e!5 e82 e58 e27 e!6 15 16 16 23 21 47 28 19 18 19 19 18 16 —— —— —— 14 35 7 13 5 2 2 4 26 8 3 4 7 5 3 3 4 3 6 5 17 29 10 3 4 4 3 3 —— —— —— e5.5 ell e.91 el. 7 e.43 e.16 e.12 e.19 el. 8 e.68 e.ll e.51 el. 3 e.57 e.17 .14 .16 .15 .42 .29 3.0 2.3 .49 .17 .18 .20 .16 .12 MARCH 16 18 23 21 27 16 16 24 19 15 15 15 15 13 13 13 12 11 11 10 13 9.9 9.8 9.5 9.5 9.5 9.8 19 16 11 11 2 3 5 5 8 5 3 6 5 2 2 2 2 2 2 2 3 4 5 3 3 1 1 2 2 3 2 7 10 4 2 .10 .14 .30 .33 .77 .21 .12 .45 .28 .09 .08 .08 .08 .07 .07 .09 .10 .13 .15 .08 .11 .04 .03 .04 .06 .07 .07 .56 .48 .14 .06 TOTAL 1185 299.05 940 32.93 451.0 5.38 e Estimated 330 RIO PAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CPS) 10 35 18 16 19 11 10 10 9.6 9.4 9.0 8.6 8.7 8.5 8.2 7.7 7.7 7.4 7.6 7.7 7.0 7.0 7.0 7.3 7.3 7.3 7.7 7.6 7.6 7.6 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MO/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MO/L) (TONS/DAY) APRIL 1 72 10 5 6 5 4 3 2 2 1 1 1 1 1 1 1 1 2 2 1 2 11 31 18 9 4 2 1 1 TOTAL 302.5 .04 26 .53 .23 .32 .15 .11 .08 .05 .04 .04 .03 .03 .02 .02 .02 .02 .03 .04 .03 .02 .04 .22 .61 .35 .18 .08 .04 .03 .02 29.42 7.4 7.3 7.3 7.6 7.7 7.8 21 26 11 10 13 11 28 13 10 10 14 10 9.5 11 13 10 10 10 9.8 27 22 14 15 13 14 400.4 MAY 2 3 4 5 4 3 9 9 4 2 3 6 16 23 13 3 3 3 2 3 4 3 3 3 2 14 5 5 5 3 2 .04 .06 .08 .09 .09 .07 1.6 .87 .12 .06 .15 .18 1.7 .78 .36 .09 .11 .08 .06 .08 .13 .08 .08 .08 .06 2.9 .83 .18 .19 .09 .10 JUNE 11.39 15 e50 e!8 12 11 9.7 9.4 10 9.0 8.7 8.7 8.5 11 10 8.1 7.5 8.0 elO 12 e20 ell 8.6 18 12 9.7 15 9.4 8.6 8.4 8.4 365.7 4 31 3 1 1 1 1 2 2 1 1 4 8 4 2 1 1 1 2 17 2 1 13 7 1 4 3 2 1 1 .15 e!3 e.16 .04 .03 .03 .03 .04 .04 .03 .03 .10 .23 .11 .04 .02 .02 e.03 .05 e2.2 e.05 .03 1.1 .26 .03 .16 .07 .04 .03 .03 18.18 e Estimated 331 RIO PAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CPS) (MO/L) (TONS/DAY) (CPS) (MG/L) (TONS/DAY) 8.4 8.2 8.0 8.0 7.9 7.6 7.9 9.1 8.9 8.1 7.8 8.6 11 9.1 8.1 9.4 9.6 9.7 12 17 99 29 29 15 15 19 13 17 13 18 16 JULY 2 2 1 1 1 1 1 2 3 4 5 5 5 3 2 1 2 3 4 5 29 11 6 2 2 6 5 6 4 5 2 TOTAL 467.4 —— YEAR e 8724.0 Estimated AUGUST .04 .04 .03 .02 .02 .02 .03 .05 .08 .09 .10 .12 .15 .07 .03 .03 .05 .08 .12 .33 22 1.2 .76 .06 .10 .30 .19 .26 .13 .32 .13 26.95 1649.98 13 13 13 17 13 12 12 12 15 45 14 13 14 16 16 31 23 24 15 14 13 61 20 25 20 18 16 15 14 13 19 579 1 1 4 6 2 1 1 2 6 16 2 4 9 6 4 10 12 10 4 1 3 28 5 6 5 2 10 9 6 3 6 —— .05 .05 .13 .27 .08 .04 .04 .05 .34 2.6 .06 .16 .32 .25 .16 1.5 .87 .62 .14 .05 .10 8.1 .26 .58 .32 .10 .46 .34 .23 .12 .32 18.71 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) SEPTEMBER 28 16 15 13 12 12 11 19 17 13 12 14 21 22 36 16 14 17 14 14 20 20 21 17 34 e430 e!9 16 15 28 23 5 2 3 2 1 1 6 8 4 2 2 7 9 9 2 1 3 2 2 3 4 5 2 27 477 7 2 1 14 4.4 .22 .09 .09 .05 .03 .03 .74 .41 .13 .05 .09 .45 .64 1.1 .10 .05 .14 .08 .07 .19 .28 .29 .08 6.9 e719 e.40 .08 .05 1.8 956 738.03 332 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DATE SEP 1997 26... TIME 0745 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. PALL DIAM. 9s FINER THAN .002 MM (70326) SED. SUSP. PALL DIAM. 9s FINER THAN .004 MM (70327) SED. SUSP. PALL DIAM. 9s FINER THAN .008 MM (70328) 908 3510 8610 22 26 34 DATE SEP 1997 26... SED. SUSP. PALL DIAM. 9s FINER THAN .016 MM (70329) SED. SUSP. PALL DIAM. 9s FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. 9s FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. 9s FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. 9s FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. 9s FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. 9s FINER THAN 1.00 MM (70335) 46 56 67 82 91 94 97 WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OP SUSPENDED SEDIMENT DATE OCT 1996 28... NOV 07... DEC 29... FEE 1997 09... MAR 28... MAY 08... JUN 20... SEP 25... 26... TIME 2245 1700 1700 0700 1800 0600 0600 1720 0759 DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- 9s FINER PER FENDED FENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) 436 161 128 e!4 22 57 43 77 1530 337 42 28 43 27 37 119 397 18 9.7 el.6 1.6 5.7 14 49 10 4670 19400 94 96 79 97 99 93 93 95 68 e Estimated RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJARDO, PR LOCATION.--Lat 18°17'56", long 65°41'42", Hydrologic Unit 21010005, on left bank off Highway 976, 0.1 mi (0.2 km) upstream from Highway 977 bridge, 0.3 mi (0.5 km) downstream from Quebrada Penon, 1.1 mi (1.8 km) northeast of Colonia Paralso, and 3.3 mi (5.3 km) southwest of Fajardo. 333 DRAINAGE AREA.--14.9 mi* (38.6 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—1960-61 (occasional low and peak-flow measurements only). March 1961 to current year. GAGE.—Water-stage recorder. Datum of gage is 137.60 ft (41.940 m) above mean sea level. Due to flood damage, gage datum has had changes as follows: Mar. 24, 1961 to May 5, 1969, 138.95 ft (42.352 m); May 6, 1969 to Mar. 16, 1972, 135.05 ft (41.163 m); Mar. 17, 1972 to Mar 25, 1975, 138.60 ft (42.245 m). REMARKS.—Records fair except those for estimated daily discharges, which are poor. Low flow affected by diversions for water supply about 400 m upstream from gaging station (estimated mean daily discharges is 9.0 ftVs (0.255 m'/s). Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT MOV DEC JAN FEB MAR APR MAY JDL AUG SEP 1 22 51 2 136 50 3 11 51 4 18 70 5 28 41 6 41 36 7 54 685 8 19 68 9 26 161 10 105 156 11 30 246 12 13 570 13 12 314 14 16 187 15 28 86 16 12 66 17 9.3 83 18 26 170 19 49 281 20 11 117 21 11 407 22 8.2 127 23 16 88 24 12 489 25 8.8 119 26 47 64 27 44 50 28 81 110 29 239 89 30 30 255 31 24 —— TOTAL 1187.3 5287 MEAN 38.3 176 MAX 239 685 MIN 8.2 36 AC-FT 2360 10490 CFSM 2.57 11.8 IN. 2.96 13.20 STATISTICS OF MONTHLY MEAN MEAN 91.0 105 MAX 260 295 (WY) 1971 1975 MIN 19.1 26.0 (WY) 1969 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 104 72 43 35 30 28 26 23 22 21 128 45 23 29 27 82 25 19 16 15 15 14 13 14 17 14 73 151 348 221 86 1779 57.4 348 13 3530 3.85 4.44 40 31 27 30 93 47 35 152 45 25 21 27 17 14 13 12 11 11 9.9 48 123 410 215 205 78 52 37 51 50 36 43 2008.9 64.8 410 9.9 3980 4.35 5.02 DATA FOR WATER 79.6 237 1976 14.9 1990 FOR 47.8 150 1996 15.4 1977 359 52 125 53 57 33 35 26 79 31 29 153 107 49 41 35 33 35 55 42 162 116 39 38 42 36 34 30 ___ ___ --- 1926 68.8 359 26 3820 4.62 4.81 YEARS 1961 38.8 80.4 1982 10.8 1983 26 32 46 45 61 31 27 55 41 27 24 25 26 22 23 26 23 22 20 20 31 19 18 18 18 17 17 37 70 26 21 914 29.5 70 17 1810 1.98 2.28 - 1997 35.0 109 1987 9.70 1977 1996 CALENDAR YEAR 29142. 79. 2610 4. 7. 57800 5. 72. 169 34 9. 5 6 Sep 10 6 May 29 4 May 24 34 76 6 18 224 126 54 77 35 30 27 26 24 24 24 23 22 20 19 18 18 17 20 17 17 17 17 16 15 17 18 16 16 --- 1012 33.7 224 15 2010 2.26 2.53 , BY WATER 43.4 129 1963 4.02 1984 19 20 20 19 19 18 77 89 22 17 25 26 80 30 15 14 23 15 13 12 24 12 11 12 13 90 88 36 23 22 23 927 29.9 90 11 1840 2.01 2.31 YEAR (WY) 90.0 399 1979 17.7 1973 26 207 31 22 14 11 10 12 9.8 8.4 8.2 8.0 12 15 8.8 7.2 7.5 17 19 64 19 10 61 29 14 25 13 10 8.8 8.1 --- 715.8 23.9 207 7.2 1420 1.60 1.79 59.2 166 1962 10.0 1985 FOR 1997 WATER YEAR 20317.9 55.7 771 6.5 7.2 6270 9.57 40300 3.74 50.73 126 26 11 Sep 26 Jul 7 JUl 1 Sep 26 Sep 26 8.0 7.8 7.6 7.1 6.9 6.6 6.5 9.9 9.4 8.4 7.8 8.0 15 13 8.1 9.8 12 10 12 40 e363 102 132 34 30 43 23 37 21 31 47 1076.9 34.7 363 6.5 2140 2.33 2.69 50.6 132 1969 11.4 1994 WATER 65 140 19 8800 1 1 21700 20 47610 4 59 128 32 10 23 19 17 28 18 14 13 15 17 190 27 18 18 24 22 66 78 52 21 15 13 e310 44 77 56 26 22 21 42 20 66 1392 44.9 310 13 2760 3.01 3.48 56.0 159 1979 9.70 1994 YEARS 1961 - .7 .0 Sep 18 .0 May 6 .5 Apr 18 Sep 18 .00 Sep 18 .86 May 3 .41 .93 219 49 28 21 17 15 14 29 37 18 11 14 34 38 194 30 20 21 15 14 28 30 33 29 185 771 42 18 16 102 —— 2092 69.7 771 11 4150 4.68 5.22 87.9 421 1989 18.9 1994 1997 1979 1994 1989 1984 1984 1989 1989 1984 e Estimated 334 RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJARDO, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1960 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1982 to September 1986 and October 1995 to current year . INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler since 1995. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 2,210 mg/L October 6, 1985; Minimum daily mean, 1 mg/L several days, 1996-97. SEDIMENT LOADS: Maximum daily mean, 22,100 tons (20,000 tonnes) October 6, 1985; Minimum daily mean, 0.01 tons (0.01 tonnes) May 06,1996. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 620 mg/L September 26, 1997; minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 4,050 tons (3,670 tonnes) September 26, 1997; minimum daily mean 0.02 tons (0.02 tonnes) July 10-12, 1997. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 31... 0930 28 120 6.9 26.5 1.3 8.4 104 <10 53000 390 FEB 1997 13... 0930 148 81 6.4 23.0 17 8.3 95 <10 2000 3800 JUN 10... 0905 8.4 124 6.6 27.0 0.25 7.1 87 <10 30 110 SEP 11... 0905 11 119 6.5 26.5 1.2 7.9 99 <10 130 200 ALKA- DATE OCT 1996 31... FEB 1997 13... JUN 10... SEP 11... DATE OCT 1996 31... FEB 1997 13... JUN 10... SEP 11... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 33 -- 33 32 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- <0.10 0.20 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 7.5 -- 7.4 6.9 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 27 -- 26 27 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 3.5 -- 3.5 3.5 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 95 -- 93 101 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 11 -- 11 13 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.15 -- 2.12 3.00 SODIUM AD- SORP- TION RATIO (00931) 0.8 -- 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) <1 14 <1 2 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.0 -- 1.0 1.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.240 0.160 0.380 0.130 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 41 30 46 39 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 0.020 <0.010 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -- NITRO- GEN, NO2+N03 TOTAL (MG/L AS N) (00630) 0.240 0.160 0.400 0.140 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 5.0 -- 3.4 3.6 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 <0.010 0.450 0.030 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 15 -- 13 14 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.26 0.05 0.21 335 RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJAROO, PR—Continued WATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE IRON, TOTAL RECOV- ERABLE (UO/L LEAD, TOTAL RECOV- ERABLE (UO/L MANGA- NESE, TOTAL RECOV- ERABLE (UO/L MERCURY TOTAL RECOV- ERABLE (UO/L SELE- NIUM, TOTAL (UO/L SILVER, TOTAL RECOV- ERABLE (UO/L ZINC, TOTAL RECOV- ERABLE (UO/L CYANIDE TOTAL (MG/L PHENOLS TOTAL METHY- LENE BLUE ACTIVE SUB- STANCE AS FB) AS PB) AS MN) AS BG) AS SE) AS AO) AS ZN) AS CN) (UO/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) OCT 1996 31... FEB 1997 13... JDN 10... SEP 11... 270 90 <10 <0.10 11 <0.10 <1 <1 <1 <1 <0.010 <1 <0.010 <1 <0.02 <0.02 PESTICIDE ANALYSES CBLOR- DATE TIME PCS, TOTAL (UO/L) (39516) ALDRIN, TOTAL (UO/L) (39330) DANE, TECB- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFILT RECOVER (UO/L) (39360) P,P'- DDE, TOTAL (UO/L) (39365) P,P'- DDT UNFILT RECOVER (UO/L) (39370) DI- AZINON, TOTAL (UO/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UO/L) (39388) JUN 1997 10... 0905 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 BNDRIN MATER UNFLTRD ETHION, DATE REG TOTAL (UQ/L) (UO/L) BEPTA- BEPTA- CHLOR MALA- CHLOR, EPOXIDE LINDANE TBION, TOTAL TOTAL TOTAL TOTAL (UO/L) (UG/L) (UO/L) (UO/L) (39390) (39398) (39410) (39420) (39340) (39530) METH- OXY- CBLOR, TOTAL (UO/L) (39480) METHYL PARA- THION, MXREX, TOTAL TOTAL (UO/L) (UO/L) (39600) (39755) JUN 1997 10... <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE PARA- PCNS THION, UNFILT TOTAL RECOVER (UO/L) (UO/L) (39540) (39250) PER- TBANE TOTAL (UO/L) (39034) TOX- APHENE, TOTAL (UG/L) (39400) TOTAL TRI- THION (UG/L) (39786) 2,4-D, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL TOTAL TOTAL (UO/L) (UG/L) (UO/L) (UG/L) (39730) (39740) (82183) (39760) JUN 1997 10... <0.010 <0.100 <0.100 <1.00 <0.010 <0.010 <0.010 <0.010 <0.010 336 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJARDO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN DISCHARGE (CFS) 22 136 11 18 28 41 54 19 26 105 30 13 12 16 28 12 9.3 26 49 11 11 8.2 16 12 8.8 47 44 81 239 30 24 MEAN CONCEN- TRATION (MG/L) OCTOBER 8 84 7 13 10 27 22 7 10 50 21 16 12 9 34 33 14 18 39 15 14 17 11 6 3 15 18 57 161 6 8 SEDIMENT DISCHARGE (TONS /DAY) .52 103 .21 .68 1.1 5.3 5.2 .37 .88 24 2.2 .54 .39 .41 2.9 1.0 .34 12 9.0 .44 .40 .37 .44 .19 .07 4.0 3.3 83 212 .56 .58 51 50 51 70 41 36 685 68 161 156 246 570 314 187 86 66 83 170 281 117 407 127 88 489 119 64 50 110 89 255 16 25 30 28 14 13 511 25 72 84 159 425 126 80 28 23 42 104 111 67 258 67 17 350 12 3 6 64 25 134 3.4 3.5 10 8.5 2.6 1.6 1410 5.1 46 64 184 770 186 72 8.8 4.4 28 70 150 34 696 36 4.3 625 5.5 .57 .85 28 7.2 128 i TO SEFTEHE MEAN DISCHARGE (CPS) DI 104 72 43 35 30 28 26 23 22 21 128 45 23 29 27 82 25 19 16 15 15 14 13 14 17 14 73 151 348 221 86 USK i»9Y MEAN CONCEN- TRATION (MG/L) 5CEMBER 35 54 27 10 4 5 7 9 10 9 54 18 5 10 8 37 7 5 4 4 4 4 5 5 5 5 23 113 202 211 106 SEDIMENT DISCHARGE (TONS/DAY) 17 11 3.2 .96 .32 .35 .51 .56 .58 .53 28 2.5 .34 .81 .77 10 .51 .24 .19 .17 .16 .16 .17 .19 .23 .20 6.4 130 274 134 25 TOTAL 1187.3 475.39 5287 4593.32 1779 649.05 RIO PAJARDO BASIN 50071000 RIO PAJARDO NR PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 337 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE THAT ION DISCHARGE DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) (CPS) (MG/L) (TONS/DAY) (CPS) (MO/L) (TONS /DAY) JANUARY 40 31 27 30 93 47 35 152 45 25 21 27 17 14 13 12 11 11 9.9 48 123 410 215 205 78 52 37 51 50 36 43 91 82 77 75 45 81 18 33 16 7 6 6 3 3 3 4 4 3 3 28 71 261 143 119 41 5 3 11 15 4 8 9.8 6.8 5.5 6.6 14 11 1.9 20 2.1 .45 .34 .55 .14 .12 .12 .13 .11 .09 .08 5.5 51 929 127 93 10 .75 .34 1.7 2.1 .34 1.6 FEBRUARY 359 52 125 53 57 33 35 26 79 31 29 153 107 49 41 35 33 35 55 42 162 116 39 38 42 36 34 30 —— ___ —— 259 18 67 20 9 2 7 12 34 9 3 87 29 4 6 4 2 2 56 13 144 68 38 37 38 37 34 11 ___ ___ —— 963 2.5 88 9.3 2.0 .22 .74 .83 19 .77 .21 122 12 .47 .66 .39 .20 .19 12 1.5 109 46 3.9 3.8 4.3 3.6 3.0 .93 —— MARCH 26 32 46 45 61 31 27 55 41 27 24 25 26 22 23 26 23 22 20 20 31 19 18 18 18 17 17 37 70 26 21 3 9 19 16 32 17 22 21 19 15 12 10 9 7 6 5 4 5 6 6 10 8 9 9 8 4 7 16 34 14 11 .19 .95 2.5 2.1 8.7 1.4 1.7 3.7 2.2 1.1 .81 .70 .62 .43 .37 .36 .26 .29 .31 .33 .90 .40 .44 .44 .39 .18 .31 3.2 11 .97 .63 TOTAL 2008.9 1302.16 1926 1410.51 914 47.88 338 RIO FAJARDO BASIN 50071000 RIO FAJARDO NR FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 18 224 126 54 77 35 30 27 26 24 24 24 23 22 20 19 18 18 17 20 17 17 17 17 16 15 17 18 16 16 MEAN ___ CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 9 156 77 19 28 4 4 9 9 7 6 6 10 17 18 16 9 5 5 7 8 7 7 7 6 4 3 2 2 3 .47 403 64 3.3 6.8 .35 .34 .64 .60 .47 .38 .35 .59 .99 .99 .85 .44 .23 .26 .40 .35 .32 .33 .32 .25 .17 .14 .11 .10 .13 MEAN DISCHARGE (CFS) 19 20 20 19 19 18 77 89 22 17 25 26 80 30 15 14 23 15 13 12 24 12 11 12 13 90 88 36 23 22 23 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 5 10 8 4 4 5 44 42 9 4 9 14 48 10 5 4 8 8 3 2 8 3 2 4 4 53 52 11 6 4 5 .27 .53 .40 .23 .23 .24 40 23 .55 .21 .97 1.0 33 .95 .21 .15 .61 .34 .12 .06 .56 .09 .06 .14 .13 63 47 1.6 .50 .27 .40 MEAN DISCHARGE (CFS) 26 207 31 22 14 11 10 12 9.8 8.4 8.2 8.0 12 15 8.8 7.2 7.5 17 19 64 19 10 61 29 14 25 13 10 8.8 8.1 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 5 118 9 8 3 2 3 3 3 4 3 2 3 4 3 4 4 5 9 38 7 2 38 8 2 5 1 2 2 1 362 .40 ! .86 .50 .10 .07 .07 .10 .09 .09 .07 .05 .15 .21 .07 .09 .08 .29 .45 33 33 .43 .07 I .90 .08 .43 .05 .05 .04 .03 TOTAL 1012 487.67 927 216.82 715.8 433.82 RIO FAJARDO BASIN 50071000 RIO FAJARDO NR FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 339 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 8.0 7.8 7.6 7.1 6.9 6.6 6.5 9.9 9.4 8.4 7.8 8.0 15 13 8.1 9.8 12 10 12 40 e363 102 132 34 30 43 23 37 21 31 47 TOTAL 1076.9 YEAR e 20317.9 Estimated MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 2 6 4 2 2 2 2 2 1 1 1 1 4 5 6 12 7 3 3 17 245 40 85 25 14 10 6 12 9 14 26 —— .05 .13 .09 .04 .04 .04 .04 .05 .04 .02 .02 .02 .27 .18 .13 .32 .24 .10 .11 3.3 ellOO 17 63 2.4 1.1 1.3 .37 1.5 .53 1.9 5.2 1199.53 15989.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 23 19 17 28 18 14 13 15 17 190 27 18 18 24 22 66 78 52 21 15 13 1310 44 77 56 26 22 21 42 20 66 4 3 2 6 3 4 7 4 3 119 7 2 1 7 5 31 32 19 6 5 6 43 27 60 71 45 89 96 75 94 57 .23 .13 .09 .57 .15 .14 .23 .18 .14 108 .53 .12 .06 .47 .30 24 17 4.4 .37 .22 .20 e63 3.9 35 13 3.5 5.4 6.2 11 5.2 13 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 219 49 28 21 17 15 14 29 37 18 11 14 34 38 194 30 20 21 15 14 28 30 33 29 185 771 42 18 16 102 139 133 109 111 110 35 7 13 47 35 26 8 12 17 151 93 93 96 95 31 6 8 11 11 133 620 9 4 3 56 232 19 8.3 6.3 5.1 1.4 .26 5.3 5.6 1.8 .79 .31 1.1 2.5 164 7.6 4.9 5.4 3.8 1.1 .40 .94 1.3 .94 272 4050 1.4 .17 .14 53 1392 316.73 2092 4856.85 340 RIO FAJARDO BASIN 50071000 RIO FAJARDO NR FAJARDO, P.R.—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE SEP 1997 01... 26... DATE SEP 1997 01... 26... TIME 1800 0820 SED. SUSP. FALL DIAM. 9s FINER THAN .016 MM (70329) 83 45 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1010 1480 SED. SUSP. FALL DIAM. 9s FINER THAN .031 MM (70330) 89 63 SEDI- MENT, SUS- PENDED (MG/L) (80154) 969 5580 SED. SUSP. SIEVE DIAM. 9s FINER THAN .062 MM (70331) 95 76 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 2640 2230 SED. SUSP. SIEVE DIAM. 9s FINER THAN .125 MM (70332) 99 91 SED. SUSP. FALL DIAM. 9s FINER THAN .002 MM (70326) 54 21 SED. SUSP. SIEVE DIAM. * FINER THAN .250 MM (70333) 99 97 SED. SUSP. FALL DIAM. 9s FINER THAN .004 MM (70327) 62 23 SED. SUSP. SIEVE DIAM. 9s FINER THAN .500 MM (70334) 100 99 SED. SUSP. FALL DIAM. 9s FINER THAN .008 MM (70328) 71 32 SED. SUSP. SIEVE DIAM. 9s FINER THAN 1.00 MM (70335) 100 99 RIO FAJARDO BASIN 50071000 —RIO FAJARDO NR FAJARDO, P.R.—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OP SUSPENDED SEDIMENT 341 DATE NOV 1996 13... 21... 21... 21... DEC 29... JAN 1997 08... FEB 01... 19... JUL 21... AUG 22... SEP 01... 26... TIME 1140 1000 1150 1540 1400 1355 1130 1610 0652 1440 1610 0822 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 212 893 505 234 878 465 2830 93 614 1400 115 1760 SEDI- MENT, SUS- PENDED (MG/L) (80154) 46 387 241 262 78 72 2460 434 1500 83 445 5240 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 26 933 328 165 185 90 18800 109 2490 314 141 24800 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 88 97 97 97 93 98 96 94 90 95 98 90 342 LOCATION.—Lat 18°19'35", east of Fajardo plaza. RIO FAJARDO BASIN 50072500 RIO FAJARDO BELOW FAJARDO, PR WATER-QUALITY RECORDS long 65°38'47", 1.2 mi (1.9 km) southwest of Playa de Fajardo, and 0.5 mi (0.8 km) DRAINAGE AREA.—23.4 mi* (60.6 km*). PERIOD OF RECORD.—Water years 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) NOV 1996 13... 1125 E250 120 6.2 25.0 79 7.3 86 21 3800 3600 FEB 1997 13... 1115 E175 103 6.3 23.5 17 8.2 98 <10 2500 4100 JUN 10... 1105 8.8 143 6.6 30.0 0.47 7.4 98 <10 220 K140 SEP 11... 1035 13 132 6.3 30.0 0.70 6.8 90 23 440 280 ALKA- DATE NOV 1996 13... FEB 1997 13... JUN 10... SEP 11... DATE NOV 1996 13... FEB 1997 13... JUN 10... SEP 11... DATE NOV 1996 13... FEB 1997 13... JUN 10... 11... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 24 — 37 36 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — <0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.63 1.0 <0.20 0.23 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 5.6 — 8.2 7.7 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 17 -- 23 25 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.97 1.2 <0.20 0.26 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 2.5 — 4.1 4.0 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 64 — 101 113 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.3 5.4 0.56 1.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 8.3 -- 13 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 43 — 2.40 3.96 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.090 0.040 <0.020 <0.020 SODIUM AD- SORP- TION RATIO (00931) 0.7 — 0.9 1.0 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 44 12 <1 2 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 — 1.1 1.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.320 0.180 <0.010 0.030 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 21 31 56 44 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.340 0.190 <0.020 0.030 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 5.3 — 3.9 4.8 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.070 0.030 0.050 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 — 15 16 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.60 0.97 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- <10 — E • estimated K • non-ideal count RIO FAJARDO BASIN 50072500 RIO FAJARDO BELOW FAJARDO, PR—Continued HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 343 DATE IRON, TOTAL RECOV- ERABLE (UG/L AS FE) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS HN) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) SELE- NIUM, TOTAL (UO/L AS SE) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) CYANIDE TOTAL (MO/L AS CN) PHENOLS TOTAL (UO/L) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 1996 13... FEB 1997 13... JUN 10... SEP 11... 2300 170 <1 <1 70 18 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 344 RIO BLANCO BASIN 50074950 QUEBRADA OUABA NEAR NAGUABO, PR LOCATION.—Lat 18°17'02", long 65°47'20", Hydrologie Unit 21010005, on right bank, off Highway 191 at El Yungue Caribbean National Forest, 4.8 mi (7.7 km) southeast of Campamento Eliza Colberg, 1.3 mi (2.1 km) southeast of Mt. Britton, 2.0 mi (3.2 km) northwest of Pico del Este and 7.3 mi (11.7 km) southeast of Rio Orande Plaza. DRAINAGE AREA.—0.05 mi 3 (0.13 km3 ). PERIOD OF RECORD.—June 1992 to current year. GAGE.—Water-stage recorder. Elevation of gage is 2,100 ft (640 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY OCT NOV 1 .29 .43 2 .24 .44 3 .35 .29 4 .22 .25 5 .21 .25 6 e.25 .27 7 e.30 1.7 8 .21 .34 9 .26 .29 10 .60 .27 11 .26 .47 12 .22 2.7 13 .25 .84 14 e.22 .56 15 e.26 .44 16 .30 .39 17 .29 .50 18 .29 .38 19 .30 .46 20 .24 .38 21 .24 .32 22 .22 .40 23 .28 .34 24 .23 2.0 25 .63 .57 26 .82 .45 27 .32 .42 28 .81 .52 29 .43 .39 30 .26 1.2 31 .22 TOTAL 10.02 18.26 MEAN .32 .61 MAX .82 2.7 MIN .21 .25 AC-FT 20 36 CFSM 2.69 5.07 IN. 3.11 5.66 DEC .61 .56 .56 .58 .52 .50 .45 .47 .43 .42 1.1 .57 .46 .42 .44 .56 .44 .43 .40 .43 .41 .38 .37 .45 .47 .56 .68 .86 1.3 .63 .63 17.09 .55 1.3 .37 34 4.59 5.30 JAN .49 .55 .47 .44 .49 .43 .39 .44 .38 .37 .38 .38 .37 .34 .36 .36 .36 .34 .41 .69 2.1 2.5 1.8 1.9 .83 .74 .49 .59 .48 .52 .51 20.90 .67 2.5 .34 41 5.62 6.48 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN .33 .49 MAX .41 .76 (WY) 1994 1993 MIN .25 .32 (WY) 1993 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS .40 .61 1993 .22 1994 FOR .47 .67 1997 .28 1994 DAILY FEB .86 .41 .52 .57 .56 .40 .41 .35 .60 .33 .34 .58 .74 .36 .33 .34 .33 .37 .46 .56 1.0 .39 .32 .32 .37 .48 .36 .32 —— —— 12.98 .46 1.0 .32 26 3.86 4.02 YEARS 1992 .44 .60 1994 .32 1993 MEAN VALUES MAR .31 .34 .39 .34 .41 .30 .30 .51 .43 .36 .34 .36 .34 .31 .34 .29 .25 .27 .24 .25 .21 .21 .18 .19 .18 .19 .18 .24 .34 .17 .17 8.94 .29 .51 .17 18 2.40 2.77 - 1997 .28 .30 1995 .23 1994 1996 CALENDAR YEAR 193. f 23 . . 384 4. 59. . . . 42 53 Sep 10 10 Apr 10 13 May 24 40 96 74 33 17 APR .16 .25 .22 .58 .54 .29 .27 .26 .27 .25 .26 .21 .25 .22 .21 .20 .21 .18 .20 .19 .16 .15 .14 .12 .12 .12 .17 .12 .11 .11 —— 6.54 .22 .58 .11 13 1.82 2.03 MAY .09 .09 .09 .10 .08 .09 .77 1.1 .55 .47 .59 .45 .68 .43 .33 .38 .76 .33 .23 .26 .31 .32 .28 .27 .22 .34 .48 .32 .50 .30 .29 11.50 .37 1.1 .08 23 3.09 3.57 JUN .37 5.3 .51 .33 .23 .21 .22 .22 .20 .18 .15 .14 .34 .19 .15 .13 .18 .32 .26 .25 .18 .16 .43 .27 .22 .31 .18 .15 .15 .14 —— 12.07 .40 5.3 .13 24 3.35 3.74 JUL .14 .15 .14 .13 .13 .13 .13 .15 .22 .14 .13 .13 .20 .26 .23 .27 .22 .18 .30 .51 1.3 .25 .52 .22 .24 .30 .20 .22 .16 .50 .25 8.05 .26 1.3 .13 16 2.16 2.50 AUG .18 .14 .28 .40 .18 .16 .20 .21 .71 .92 .32 .34 .31 .25 .28 .73 .55 .71 .28 .24 .25 2.6 .44 .52 .41 .36 .33 .29 .28 .30 .35 13.52 .44 2.6 .14 27 3.63 4.19 SEP .39 .37 .29 .23 .21 .22 .22 .30 .31 .23 .22 .26 .77 .41 .51 .28 .23 .28 .22 .26 .48 .47 .39 .32 .76 1.4 .50 .43 .44 .44 —— 11.84 .39 1.4 .21 23 3.29 3.67 , BY WATER YEAR (WY) .28 .33 1994 .21 1995 FOR 1997 151 5 92 10 301 3 47 .39 .61 1993 .32 1996 WATER YEAR .71 .42 .3 Jun 2 .08 May 5 .09 Apr 30 Jun 2 .58 Jun 2 . 05 May 1 .46 .03 .63 .33 .16 .38 .50 1996 .32 1993 .53 1.18 1992 .22 1994 WATER 23 102 10 290 3 45 .37 .56 1992 .19 1993 YEARS 1992 .40 .49 .32 Sep .08 May .09 Apr Sep .74 Sep .05 May .34 .37 .70 .28 .16 .58 1.42 1996 .34 1993 - 1997 1996 1994 10 1996 5 1997 30 1997 10 1996 10 1996 1 1997 e Estimated RIO BLANCO BASIN 50075000 RIO ICACOS NEAR NAGUABO, PR 345 LOCATION.—Lat 18°16'38", long 65°47'09", Hydrologic Unit 21010005, in Caribbean National Forest, at Highway 191, at El Yunque, 1.6 mi (2.6 km) upstream from confluence with Rio Cubuy, 2.8 mi (4.5 km) north of Florida, and 5.3 mi (8.5 km) northwest of Naguabo Plaza. DRAINAGE AREA.--1.26 mi a (3.26 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—July 1945 to March 1953 (operated by Puerto Rico Water Resources Authority), annual maximum, water years 1953-62, annual low-flow measurements 1962-66, October 1979 to current year. GAGE.—Water-stage recorder, crest-stage gage and sharp-crested weir. Elevation of gage is 2,020 ft (616 m), from topographic map. REMARKS.—Records fair. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC MAR JUN AUG SEP 1 15 23 2 16 25 3 23 19 4 16 14 5 13 16 6 12 18 7 15 97 8 11 20 9 15 16 10 30 16 11 13 43 12 11 124 13 12 56 14 11 41 15 14 31 16 10 30 17 10 38 18 10 32 19 10 36 20 10 32 21 10 28 22 8.7 33 23 12 29 24 9.2 113 25 27 36 26 44 29 27 15 30 28 39 39 29 25 34 30 11 83 31 10 —— TOTAL 487.9 1181 MEAN 15.7 39.4 MAX 44 124 MIN 8.7 14 AC-FT 968 2340 CFSM 12.5 31.2 IN. 14.40 34.87 49 26 17 17 15 14 14 13 12 13 56 21 13 13 14 21 12 11 10 10 10 9.7 8.0 12 16 22 29 40 61 32 31 641.7 20.7 61 8.0 1270 16.4 18.95 19 25 19 19 22 18 16 19 17 15 16 15 14 14 13 13 13 13 19 28 72 92 74 74 33 36 22 31 27 25 28 861 27.8 92 13 1710 22.0 25.42 55 29 40 39 40 31 30 25 47 26 26 43 47 26 24 23 22 23 32 33 64 31 24 24 25 30 21 17 —— —— 897 32.0 64 17 1780 25.4 26.48 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1945 MEAN 15.3 19.1 MAX 32.1 46.9 (WY) 1986 1951 MIN 4.78 8.03 (WY) 1993 1948 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 15.6 31.3 1988 4.99 1990 FOR 14.0 28.4 1996 6.65 1994 14.4 44.0 1950 4.86 1983 13 15 20 17 26 12 11 25 16 11 9.6 11 10 9.3 12 11 8.8 9.0 8.2 8.2 9.0 8.0 8.1 8.0 8.8 9.4 9.8 14 19 10 9.7 376.9 12.2 26 8.0 748 9.65 11.13 - 1997 10.5 26.2 1949 3.90 1951 1996 CALENDAR YEAR 8296.6 22.7 737 3.2 4.4 16460 18.0 244.95 37 15 6.5 Sep 10 Apr 10 Apr 5 9.0 14 12 24 25 10 9.0 9.0 8.2 8.0 8.2 8.0 11 8.0 7.9 8.0 8.6 8.4 11 8.4 7.9 7.2 6.7 5.7 5.7 5.7 7.2 5.9 5.7 5.7 —— 279.1 9.30 25 5.7 554 7.38 8.24 , BY WATER 12.1 34.4 1950 4.77 1984 FOR 1997 6888 18 172 2 3 1110 6 2 13660 15 203 37 13 5 5.5 5.1 4.8 4.7 4.5 4.5 46 37 11 7.6 17 9.3 21 10 7.2 9.3 20 10 8.6 10 11 8.7 8.0 8.8 8.0 15 19 8.2 22 9.1 11 381.9 12.3 46 4.5 757 9.78 11.28 YEAR (WY) 16.5 26.6 1948 6.84 1994 15 172 19 9.6 7.6 7.3 6.4 7.7 6.5 6.4 6.4 6.1 17 9.9 6.0 5.7 7.3 13 11 20 11 6.9 23 9.6 6.8 16 5.3 4.2 3.6 3.5 —— 449.8 15.0 172 3.5 892 11.9 13.28 12.7 23.7 1996 5.19 1985 WATER YEAR .3 .9 .7 .2 .42 .5 .0 .37 .6 Jun 2 Jul 11 Jul 6 Jun 2 Jun 2 Jul 6 3.5 3.4 3.2 3.2 3.6 3.1 2.9 3.9 3.8 2.9 2.7 2.9 6.1 5.3 6.2 7.6 5.7 3.8 12 23 69 12 23 3.7 5.6 7.5 3.3 4.7 3.2 23 8.6 272.4 8.79 69 2.7 540 6.97 8.04 13.8 39.0 1952 7.21 1994 WATER 14 21 8 737 1 2 2860 8 2 10650 11 158 29 8 4 4.3 4.1 14 20 6.0 4.9 6.2 6.0 17 50 21 26 26 21 24 46 38 44 22 19 18 114 14 19 11 8.7 6.9 6.0 5.7 5.4 9.2 637.4 20.6 114 4.1 1260 16.3 18.82 14.7 24.5 1945 5.91 1993 YEARS 1945 .7 .1 .00 Sep .5 Mar .0 Apr Apr .96 Apr .5 Jul .7 .48 .4 .6 13 9.1 7.7 6.9 5.3 5.2 5.0 11 13 5.8 5.1 7.5 32 22 24 8.2 6.4 9.4 5.7 6.5 18 21 18 8.4 29 75 10 10 13 11—— 422.2 14.1 75 5.0 837 11.2 12.46 18.0 51.7 1996 7.03 1986 - 1997 1952 1994 10 1996 22 1946 7 1946 21 1983 21 1983 6 1997 346 THIS PAGE WAS LEFT BLANK INTENTIONALLY 0123456 KILOMETERS H-——-L-——i 01234 MILES I.X Mop or<?a~ CARIBBEAN SEA EXPLANATION A0920 SURFACE-WATER STATION AND NUMBER ^0835 QUALITY-OF-WATER STATION AND NUMBER 096 WELL AND WELL NUMBER H093045 LAKE-ELEVATION STATION AND NUMBER Figure 21.--Southeastern river basins the Rfo Humacao to Rfo Seco basins. c* fe N 348 RIO HUMACAO BASIN 50081000 RIO HUMACAO AT LAS PIEDRAS, PR LOCATION.—Lat 18°10'27", long 65°52'11", Hydrologic unit 21010005, on left bank at downstream side of bridge on Highway 921, 0.6 mi (1.0 km) southeast of junction with Highway 30, 0.8 mi (1.3 km) downstream from Quebrada Blanca and 0.8 mi (1.3 km) south of Las Piedras. DRAINAGE AREA.—6.65 mi* (17.22 km2 ). PERIOD OF RECORD.—September 1958 to December 1967 (monthly discharge measurements), July 1974 to September 1977, October 1987 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 260 ft (79 m), from topographic map. Prior to July 1974, crest-stage gage at different datum. July 1974 to September 1977 at site 90 ft (27 m) upstream at present datum. REMARKS.—Records fair except those for estimated daily discharges, and above 1,000 ftVs (28.3 mVs), which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR JUN JUL AUG SEP 1 33 22 2 e33 22 3 e31 22 4 31 35 5 30 21 6 e29 27 7 35 181 8 28 38 9 35 27 10 55 25 11 35 48 12 29 120 13 27 93 14 28 51 15 27 44 16 26 35 17 25 31 18 24 28 19 24 105 20 23 37 21 23 79 22 22 35 23 22 e33 24 21 30 25 21 28 26 25 27 27 26 26 28 e24 26 29 26 26 30 22 26 31 21 TOTAL 861 1348 MEAN 27.8 44.9 MAX 55 181 MIN 21 21 AC-FT 1710 2670 CFSM 4.18 6.76 IN. 4.82 7.54 STATISTICS OF MONTHLY MEAN MEAN 28.5 36.9 MAX 74.9 126 (WY) 1975 1988 MIN 12.8 13.4 (WY) 1995 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 25 24 24 23 23 22 27 23 22 22 e24 e21 e21 e20 e22 e21 e!9 e!9 e!9 19 19 18 18 18 19 18 18 18 21 27 19 653 21.1 27 18 1300 3.17 3.65 DATA 30.0 112 1988 11.5 1992 17 17 17 16 16 16 16 16 16 16 17 15 15 15 15 15 14 14 14 15 15 37 18 17 15 17 14 15 15 14 15 504 16.3 37 14 1000 2.44 2.82 42 55 21 16 29 27 20 17 19 16 17 24 28 23 20 21 19 18 18 17 21 21 21 17 19 23 17 16 —— —— —— 622 22.2 55 16 1230 3.34 3.48 FOR WATER YEARS 1974 18.9 34.1 1992 10.5 1995 15.8 22.2 1997 11.0 1977 16 16 16 18 16 16 15 16 16 15 15 16 16 15 15 19 16 17 16 15 14 14 14 13 13 13 14 13 14 14 14 470 15.2 19 13 932 2.28 2.63 - 1997 11.6 16.4 1989 8.87 1996 FOR 1996 CALENDAR YEAR 11642.0 31.8 2010 6.2 6.8 23090 4.78 65.13 53 18 7.8 Sep 10 May 5 May 1 13 78 41 17 16 15 14 14 13 13 13 13 13 12 12 12 12 11 11 11 11 10 10 10 9.8 9.6 9.8 9.7 9.7 9.5 —— 453.1 15.1 78 9.5 899 2.27 2.53 9.1 8.9 8.6 8.6 9.0 8.5 8.2 8.5 11 16 27 15 13 11 15 13 12 10 9.6 11 12 9.8 9.3 9.1 9.8 9.2 29 17 19 12 16 385.2 12.4 29 8.2 764 1.87 2.15 12 14 16 12 12 ell e9. 8 e9.0 e9. 5 e9.0 e9.0 e8.5 e8.5 e!4 e8.6 e8.6 e8.0 e7.6 14 11 8.2 7.2 13 13 8.9 11 8.5 7.7 7.4 7.2 —— 304.2 10.1 16 7.2 603 1.52 1.70 7.2 6.8 6.9 6.4 7.4 13 7.8 7.9 10 7.5 7.0 7.0 12 7.0 6.3 9.7 8.7 9.2 9.3 10 261 e65 19 23 15 13 13 23 13 50 17 679.1 21.9 261 6.3 1350 3.29 3.80 14 13 14 13 12 12 12 13 14 17 14 14 13 13 15 18 14 98 24 16 25 71 25 138 41 20 18 39 24 17 29 820 26.5 138 12 1630 3.98 4.59 17 17 15 15 14 14 13 20 14 13 12 14 13 23 19 14 13 15 13 12 21 19 21 51 18 73 22 18 19 25 —— 587 19.6 73 12 1160 2.94 3.28 , BY WATER YEAR (WY) 9.61 15.1 1997 5.88 1977 13.9 42.2 1992 7.26 1990 17.5 41.1 1996 5.91 1977 FOR 1997 WATER YEAR 7686.6 21.1 261 6.3 7.0 1890 6.10 5.5 15250 3.17 43.00 31 16 9.1 Jul 21 Jul 15 Jun 29 Jul 21 Jul 21 Jul 4 19.7 38.1 1993 7.95 1990 20.0 34.7 1996 9.45 1974 WATER YEARS 1974 - 21.7 37.6 12.1 2010 2.2 2.8 20800 34.40 15730 3.27 44.37 32 13 7.1 Sep 10 Jul 15 Jul 19 Sep 6 Sep 6 36.4 121 1996 10.0 1990 1997 1988 1990 1996 1974 1974 1960 1960 e Estimated 349 RIO HUMACAO BASIN 50082000 RIO HOMACAO AT HIGHWAY 3 AT BOMACAO, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°08'49", long 65°49'37", at bridge on Highway 3,300 ft (91 m) downstream from Quebrada Mariana, and 0.4 mi (0.6 km) south of Humacao. DRAINAGE AREA.—17.3 mi' (44.8 km1 ). PERIOD OF RECORD.—Hater years 1958-66, 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. 1ATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DBG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) L996 1050 34 302 7.0 29.5 6.2 7.4 96 <10 5700 450 L997 1115 22 475 6.7 26.5 5.5 6.6 81 12 3400 2800 0835 11 368 6.8 26.0 6.0 6.9 85 <10 21000 4100 1000 150 147 6.9 26.5 320 7.1 88 20 55000 55000 ALKA- DATE OCT 1996 18... FEB 1997 24... MAY 22... AUG 28... DATE OCT 1996 18... FEB 1997 24... MAY 22... AUG 28... DATE OCT 1996 18... FEB 1997 24... MAY 22... AUG 28... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 93 — 110 38 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.35 0.53 0.36 2.3 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 — 32 10 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 38 — 39 20 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.95 1.2 0.79 2.7 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.9 — 7.5 2.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 191 — 229 91 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 4.2 5.2 3.5 12 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 24 — 29 11 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 17.8 — 6.91 36.9 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.070 0.040 0.500 SODIUM AD- SORP- TION RATIO (00931) 1 — 1 0.8 RESIDUE TOTAL AT 105 DBG. C, SUS- PENDED (MG/L) (00530) 18 16 8 556 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 ~ POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 — 2.4 3.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620> 0.600 0.630 0.420 0.390 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 ~ LINITY WAT HH TOT FET FIELD MG/L AS CACO3 (00410) 93 120 110 43 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.020 0.020 0.018 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.600 0.650 0.440 0.410 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS 804) (00945) 9.3 — 11 4.7 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.230 0.060 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 29 — 42 13 NITRO- GEMy ORGANIC TOTAL (MG/L AS N) (00605) 0.33 0.29 0.30 2.2 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K - non- ideal count 350 RIO HOMACAO BASIN 50082000 RIO HUMACAO AT HIGHWAY 3 AT HUMACAO, PR—Continued HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 18... FEB 1997 24... MAY 22... AUO 28... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 830 400 120 <0.10 70 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.02 RIO GUAYANES BASIN 50083500 RIO GUAYANES AT YABUCOA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°03'33", long 65°54'03", at bridge on Highway 182, 1.4 mi (2.2 km) west-northwest of Yabucoa plaza. DRAINAGE AREA.—17.2 mi* (44.6 km*). PERIOD OF RECORD.—Water years 1958-62, 1968-70, 1980 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 351 DATE OCT 1996 10... FEB 1997 21... HAY 19... AUO 22... OCT 10 FEB 21 MAY 19 AUG 22 OCT 10 FEB 21 MAY 19 AUG 22 OCT DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (HG/L) ATION) (HO/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0930 62 175 6.6 25.0 34 7.2 85 <10 2700 3400 1030 65 212 6.6 22.0 54 8.6 96 17 49000 31000 1115 20 210 6.6 26.5 47 7.0 86 12 2500 4100 1045 E350 74 6.6 25.5 52 7.2 88 20 32000 61000 ALKA- DATE 1996 ... 1997 ... ... ... DATE 1996 ... 1997 ... ... DATE 1996 10... FEB 21 MAY 19 AUG 1997 ... ... 22... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 51 -- 66 44 FLUO- RIDE, DIS- SOLVED (HG/L AS F) (00950) 0.10 — 0.12 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.22 0.65 0.47 2.2 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 13 — 17 11 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 35 -- 38 33 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.75 1.1 0.74 2.5 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 4.5 __ 5.5 3.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (HG/L) (70301) 123 -- 151 107 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 3.3 4.9 3.3 11 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 14 __ 17 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 21 -_ 8.02 E101 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.050 0.100 0.080 0.270 SODIUM AD- SORP- TION RATIO (00931) 0.9 — 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 48 27 92 88 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.7 __ 1.8 1.6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.520 0.450 0.260 0.220 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 57 66 84 20 NITRO- GEN, NITRITE TOTAL (HG/L AS N) (00615) <0.010 0.010 <0.010 0.059 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- 50 — SULFIDE TOTAL (HG/L AS S) (00745) 1.8 __ <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (HG/L AS N) (00630) 0.530 0.460 0.270 0.280 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 4.4 __ 5.2 3.6 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.330 0.040 0.030 0.070 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 15 -_ 16 12 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.61 0.44 2.1 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 <10 — K « non-ideal count E « estimated 352 RIO GUAYANES BASIN 50083500 RIO GUAYANES AT YABUCOA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 10... FEE 1997 21... HAY 19... AU6 22... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) SELE- NIUM, TOTAL (UG/L AS SE) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) CYANIDE TOTAL (MG/L AS CN) PHENOLS TOTAL (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 2600 800 <1 <1 160 120 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 <0.01 PESTICIDE ANALYSES DATE MAY 1997 19... PCB, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFILT RECOVER (UG/L) (39360) P,P'- DDE, TOTAL (UG/L) (39365) P,P'- DDT UNPILT RECOVER (UG/L) (39370) DI- AZINON, TOTAL (UG/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UG/L) (39388) 1115 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) MAY 1997 19... HEPTA- HEPTA- CHLOR MALA- CHLOR, EPOXIDE LINDANE THION, TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) METH- OXY- CHLOR, TOTAL (UG/L) METHYL PARA- THION, MIREX, TOTAL TOTAL (UG/L) (UG/L) (39390) (39398) (39410) (39420) (39340) (39530) (39480) (39600) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE MAY 1997 19... PARA- THION, TOTAL (UG/L) (39540) <0.010 PCNS UNFILT RECOVER (UG/L) (39250) <0.100 PER- THANE TOTAL (UG/L) (39034) <0.100 TOX- APHENE, TOTAL (UG/L) (39400) <1.00 TOTAL TRI- THION (UG/L) (39786) <0.010 2,4-D, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (39730) (39740) (82183) (39760) <0.010 <0.010 <0.010 <0.010 RIO GUAYANES BASIN 50086500 RIO GUAYANES ABOVE MOUTH AT PLAYA DE GUAYANES, PR WATER-QUALITY RECORDS LOCATION.—Lat 18»03'45", long 65°49'42", at old railroad croiiing, 0.2 mi (0.3 km) from mouth, 0.4 mi (0.6 km) weit of Playa de Guayanei, and 3.5 mi (5.6 km) northeait of Yabucoa plaza. DRAINAGE AREA.— 34.0 mi» (88.1km2 ). PERIOD OF RECORD.—Water yeari 1974 to current year. 353 OCT 10 FEB 24 MAY 22 AUG 28 DATE 1996 1997 . . . ... ... DATE OCT 1996 10... FEB 1997 24... MAY 22... AUG 28... WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DBG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1100 110 0915 1000 0835 300 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 53 -- 59 58 - - CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 14 -- 15 15 184 450 209 232 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 4.5 -- 4.9 5.1 6.8 6.7 6.8 6.7 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 15 -- 18 19 26.5 54 25.0 17 26.0 18 28.0 59 SODIUM AD- SORP- TION RATIO (00931) 0.9 — 1 1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 -- 2.2 3.2 7.2 5.0 6.4 4.2 ALKA- LINITY WAT WH TOT PET FIELD MG/L AS CACO3 (00410) 62 110 82 79 88 59 78 54 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — <10 2200 17 5200 <10 K900 4100 4400 600 16 22000 53000 CHLO- SULFATE RIDE, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS SO4) AS CL) (00945) (00940) 6.4 18 — 5.3 18 3.8 19 DATE OCT 1996 10... FEB 1997 24... MAY 22... AUG 28... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.12 0.15 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 36 — 38 32 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 131 — 151 144 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 39 — — 117 RESIDUE TOTAL AT 105 DBG. C, SUS- PENDED (MG/L) (00530) 92 22 25 58 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.610 <0.230 0.270 0.230 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 <0.010 0.015 NITRO- GEN* NO2+N03 TOTAL (MG/L AS N) (00630) 0.620 0.240 0.270 0.250 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.050 0.040 0.050 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.41 0.27 0.72 DATE OCT 1996 10... FEB 1997 24... NAY 22... AUG 28... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.23 0.46 0.31 0.77 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.85 0.71 0.58 1.0 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 3.8 3.1 2.6 4.5 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.080 0.070 0.040 0.200 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- <10 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 -- COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) ^10 — ^10 — non-ideal count 354 OCT 1996 10... FEE 1997 24... HAY 22... AUG 28... RIO GUAYANES BASIN 50086500 RIO GUAYANES ABOVE MOUTH AT PLAYA DE GUAYANES, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IRON, TOTAL RECOV- ERABLE (UG/L 3500 2900 MANGA- METHY- LEAD, TOTAL RECOV- ERABLE (UG/L TOTAL RECOV- ERABLE (UG/L MERCURY SILVER, ZINC, TOTAL SELE- TOTAL TOTAL RECOV- NIUM, RBCOV- RECOV- CYANIDE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 180 120 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 <0.01 RIO MAUNABO BASIN 50090500 RIO MAUNABO AT LIZAS, PR LOCATION.—Lat 18°01'38", long 65°56'24", Hydrologic Unit 21010005, on right bank, off Highway 759 at Lizas, about 1.0 mi (1.6 km) downstream from Quebrada Coroco, and about 3.0 mi (4.8 km) northwest of Maunabo. DRAINAGE AREA.--5.38 mi* (13.93 km*). PERIOD OF RECORD.—February 1971 to January 1985, February 1991 to current year. GAGE.—water-stage recorder and crest-stage gage. Elevation of gage is 230 ft (70 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 355 OCT NOV DEC JAN FEB HAY JUL AUG SEP 1 36 23 2 e35 22 3 e34 e!8 4 31 24 5 31 18 6 e29 el? 7 47 23 8 29 e!7 9 28 e39 10 e33 22 11 e28 56 12 25 156 13 23 48 14 24 43 15 26 28 16 22 22 17 e21 18 18 e31 17 19 e30 28 20 22 30 21 20 18 22 19 15 23 18 16 24 18 e!5 25 17 e!4 26 34 e!3 27 25 13 28 45 12 29 22 e!2 30 19 13 31 18 TOTAL 840 810 MEAN 27.1 27.0 MAX 47 156 MIN 17 12 AC-PT 1670 1610 CFSM 5.04 5.02 IN. 5.81 5.60 11 10 e9.4 e8.2 8.1 8.4 e9.5 e8.3 8.3 e9.4 e9.2 8.3 8.2 8.3 8.6 8.5 8.2 8.0 7.8 8.1 8.1 7.7 7.7 11 12 9.7 9.7 9.3 14 e!2 9.2 284.2 9.17 14 7.7 564 1.70 1.97 STATISTICS OF MONTHLY MEAN DATA MEAN 26.7 31.1 MAX 52.6 88.9 (WY) 1979 1978 MIN 10.4 7.46 (WY) 1994 1982 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 17.7 35.2 1978 8.74 1994 FOR 8.9 8.6 9.0 9.0 8.8 8.6 e8.8 e9.2 e9.6 9.5 17 11 e9.9 8.9 8.3 8.4 e8.5 8.0 7.7 8.0 8.4 30 e!2 9.5 8.3 12 8.0 e21 12 11 10 327.9 10.6 30 7.7 650 1.97 2.27 FOR WATER 13.0 27.1 1992 7.79 1981 54 27 21 13 e56 36 15 11 14 10 11 10 33 21 13 12 10 9.5 12 11 38 21 13 14 11 19 12 9.0 —— —— 536.5 19.2 56 9.0 1060 3.56 3.71 YEARS 1971 12.5 24.5 1982 6.10 1979 9.4 e9.7 ell e!4 13 e9.7 e8.0 e9.8 7.9 7.1 6.9 9.1 9.2 7.4 e8.4 18 10 21 11 7.9 7.0 6.2 5.8 5.8 6.2 6.2 6.1 6.5 6.8 6.7 8.7 280.5 9.05 21 5.8 556 1.68 1.94 - 1997 9.80 18.9 1976 4.32 1979 1996 CALENDAR YEAR 10006. 27. 1280 5. 6. 19850 5. 69. 47 17 8. 9 3 Sep 10 7 May 30 5 May 24 08 19 1 8.0 40 25 11 8.7 7.6 7.4 7.2 7.1 7.0 6.8 6.8 7.3 6.8 6.4 6.1 6.0 6.1 5.6 5.5 5.5 5.4 5.3 5.1 5.0 5.4 5.2 5.3 5.2 5.8 —— 245.6 8.19 40 5.0 487 1.52 1.70 5.8 5.2 4.8 5.0 5.0 5.2 8.0 6.6 9.0 7.9 6.2 7.0 7.2 6.3 6.1 6.4 6.8 6.8 5.4 5.4 5.6 5.0 5.0 5.5 6.7 6.9 7.0 8.0 27 13 11 226.8 7.32 27 4.8 450 1.36 1.57 11 elO 15 9.0 8.3 8.3 e7.7 e6.5 e6.0 e5.8 e6.2 e6.0 e8.0 e!2 e7.0 e6.3 e5.8 e5.5 e6.1 e5.9 eS.l 4.7 4.9 4.4 3.8 4.2 3.8 3.6 3.5 4.6 —— 199.0 6.63 15 3.5 395 1.23 1.38 4.1 3.7 3.5 3.3 3.9 4.1 3.7 3.8 .0 .2 .1 .5 .6 .3 .4 4.8 5.2 11 21 31 88 18 e30 e!8 15 22 13 74 e!7 e!2 8.7 450.9 14.5 88 3.3 894 2.70 3.12 7.6 e7.1 e8.2 11 8.1 7.7 7.0 6.6 14 14 elO e8.9 20 8.4 8.5 9.3 16 93 14 9.7 8.7 63 26 16 15 11 28 28 15 13 21 533.8 17.2 93 6.6 1060 3.20 3.69 13 12 9.8 10 8.9 8.6 8.2 8.1 7.9 7.9 7.7 7.6 7.6 8.3 79 12 9.5 8.5 7.7 7.5 35 22 19 21 12 113 15 13 15 17—— 531.8 17.7 113 7.5 1050 3.29 3.68 , BY WATER YEAR (WY) 7.21 10.8 1976 3.92 1979 12.7 25.1 1979 5.13 1974 17.9 47.1 1979 4.40 1974 FOR 1997 WATER YEAR 5267.0 14.4 156 3.3 3.7 1080 7.97 10450 2.68 36.42 28 9.3 5.2 Nov 12 Jul 4 Jul 2 Sep 26 Sep 26 17.6 40.2 1993 3.70 1974 WATER 18 36 10 2480 2 2 9950 17 13200 3 46 33 11 5 22.7 131 1979 6.18 1974 YEARS 1971 .2 .7 .8 Aug .2 Jul .8 Jul Sep .46 Sep .39 .02 .2 28.6 94.6 1996 7.99 1980 - 1997 1979 1994 31 1979 16 1974 11 1974 20 1994 20 1994 e Estimated 356 RIO MAUNABO BASIN 50091000 RIO MAUNABO AT MAUNABO, PR HATER-QUALITY RECORDS LOCATION.--Lat 18°00'24-, long 65°54'19-, at bridge on Highway 3, 0.4 mi (0.6 km) southwest of Maunabo plaza, and 1.3 mi (2.1 km) upstream from mouth. DRAINAGE AREA.--12.4 mi 2 (32.1 km 2 ). PERIOD OF RECORD.--Hater years 1958-66, 1975 to current year. HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 18 FEB 21 MAY 19 AUG 22 DATE 1996 1997 . . . ... DATE OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- HATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD HATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0900 24 0900 0850 7 0900 75 HARD- NESS TOTAL (MG/L AS CAC03) (00900) 86 -- 89 73 - .7 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 22 -- 22 18 270 210 273 172 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.6 -- 8.1 6.8 6.9 6.7 6.8 6.6 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 20 __ 21 19 25.0 5. 22.5 240 25.5 2. 26.0 2. SODIUM AD- SORP- TION RATIO (00931) 0.9 -- 1 1 5 2 8 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.5 — 1.3 1.5 7.3 6.8 7.5 7.9 ALKA- LINITY HAT HH TOT PET FIELD MG/L AS CACO3 (00410) 92 85 100 66 87 77 91 97 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — <10 2000 800 55 210000 220000 <10 K1800 870 <10 46000 69000 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 9.0 -- 13 10 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 20 -- 26 20 DATE FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... 0.10 -- 0.14 0.10 37 39 36 172 191 154 11.1 3.99 31.2 NITRO- NITRO- NITRO- NITRO- NITRO- GEN, GEN, GEN, GEN, GEN, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC TOTAL TOTAL TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L (MG/L (MG/L AS N) AS N) AS N) AS N) AS N) (00620) (00615) (00630) (00610) (00605) 46 810 6 19 0.470 0.360 0.150 0.220 <0.010 0.020 <0.010 0.028 0.480 0.380 0.160 0.250 0.020 0.060 0.020 0.040 0.41 2.7 <0.20 1.0 DATE OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.43 2.7 0.20 1.1 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.91 3.1 0.36 1.3 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.0 14 1.6 5.8 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.070 0.610 <0.020 0.130 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 -- BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- <10 — CADMIUM HATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- <10 — non-ideal count RIO MAUNABO BASIN 50091000 RIO MAUNABO AT MAUNABO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 357 DATE IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) HETHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... 2000 730 150 <0.10 60 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 358 RIO CHICO BASIN 50091800 RIO CHICO AT PROVIDENCIA, PR WATER-QUALITY RECORDS LOCATION.—Lat 17°59'16", long 66°00'18", at flat low bridge 200 ft (61 m) south of Highway above mouth, and 1.5 mi (2.4 km) southeast of patillas plaza. DRAINAGE AREA.—4.9 mi 2 (12.8 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. HATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 3, 0.5 mi (0.8 km) DATE OCT 1996 29... FEE 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DIS- PH OXYGEN, OXYGEN COLI- CHAR6E, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0850 4.0 374 7.3 27.0 3.4 6.7 82 18 K7200 2000 0850 2.4 434 7.0 24.5 3.0 6.0 71 37 K930 700 0920 2.7 513 6.9 28.0 74 0.9 12 320 K600000 780000 0905 3.8 365 7.0 27.5 3.6 5.7 72 24 K730 570 ALKA- HARD- NESS TOTAL (MG/L AS CACO3) (00900) 97 — 83 100 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — 0.12 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.2 13 36 1.6 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 24 — 20 25 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 29 — 25 30 NITRO- GEN, TOTAL (MG/L AS N) (00600) 4.6 13 36 4.8 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 9.0 — 7.9 10 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 214 — 262 207 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 21 59 160 21 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 36 — 38 36 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 2.29 — 1.94 2.12 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 1.10 1.40 5.90 1.00 SODIUM AD- SORP- TION RATIO (00931) 2 — 2 2 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 48 9 180 18 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.4 — 5.9 2.8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 3.40 0.220 0.00 3.00 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 100 170 180 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.090 0.160 0.020 0.170 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 70 — 80 __ SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+N03 TOTAL (MG/L AS N) (00630) 3.50 0.380 0.020 3.10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 __ SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 17 — 15 19 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.150 13.0 20.0 0.730 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — 3 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 34 — 42 28 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.0 0.0 16 0.92 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 69 — K = non-ideal count RIO CHICO BASIN 50091800 RIO CHICO AT PROVIDENCIA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 359 DATE OCT 1996 29... FEB 1997 12... MAY 13... AUO 25... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) SELE- NIUM, TOTAL (UO/L AS SB) SILVER, TOTAL RECOV- ERABLE (UO/L AS AC) ZINC, TOTAL RBCOV- ERABL1 (UO/L AS ZN; 1600 3900 TOTAL PHENOLS (MO/L TOTAL AS CN) (UO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 90 <0.10 170 <0.10 <1 <1 10 <0.010 250 <0.010 BLUE ACTIVE SUB- STANCE (MO/L) (38260) 0.04 4.8 360 RZO GRANDE DE PATZLLAS BASIN 50092000 RZO GRANDE DE PATZLLAS NEAR PATILIAS, PR LOCATION.--Lat 18°02'04", long 66°01'58", Hydrologic Unit 21010004, on left bank, at foot bridge, off Highway 184, 1.2 mi (1.9 km) upstream from Lago Patillas Dam and 2.2 mi (3.5 km) northwest of Patillas. DRAINAGE AREA.--18.3 mi 2 (47.4 km2 ). WATER-DISCHARGE RECORDS PERZOD OF RECORD.—February 1959 to October 1965 (annual low-flow and occasional measurements only), January 1966 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 235 ft (72 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY OCT NOV 1 e62 59 2 e60 53 3 e62 41 4 e58 68 5 e54 42 6 e54 46 7 e52 42 8 e56 42 9 e66 42 10 e!20 37 11 e75 160 12 e60 333 13 e50 210 14 e48 84 15 e50 62 16 e43 52 17 e39 47 18 42 44 19 83 45 20 69 46 21 45 55 22 38 51 23 35 50 24 33 42 25 32 37 26 35 35 27 36 34 28 36 35 29 35 33 30 33 37 31 48 —— TOTAL 1609 1964 MEAN 51.9 65.5 MAX 120 333 MZN 32 33 AC-FT 3190 3900 CFSM 2.84 3.58 ZN. 3.27 3.99 STATZSTZCS OF MONTHLY MEAN MEAN 95.9 89.0 MAX 593 393 (WY) 1971 1978 MZN 14.4 16.1 (WY) 1968 1968 SUMMARY STATZSTZCS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAZLY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 34 33 30 31 28 26 27 26 26 25 49 30 26 25 25 24 23 23 22 22 22 21 21 22 24 22 21 20 37 68 24 857 27.6 68 20 1700 1.51 1.74 JAN 22 21 20 19 18 18 18 18 18 18 72 27 21 19 19 18 18 17 17 20 28 118 28 25 24 26 21 22 21 21 22 794 25.6 118 17 1570 1.40 1.61 DAILY FEE 104 55 40 28 30 43 28 27 31 29 29 28 86 54 39 34 30 28 29 26 42 38 41 33 29 76 35 29 —— 1121 40.0 104 26 2220 2.19 2.28 DATA FOR WATER YEARS 1966 50.2 152 1971 8.63 1968 FOR 34.3 125 1992 14.0 1973 28.7 94.6 1982 7.09 1973 MEAN VALUES MAR 27 26 27 27 24 23 23 25 23 22 20 21 24 22 28 31 24 25 22 20 20 19 17 16 15 15 15 15 18 16 18 668 21.5 31 15 1320 1.18 1.36 - 1997 24.5 45.5 1996 6.74 1968 1996 CALENDAR YEAR 22945 62.7 1770 18 19 45510 3.43 46.64 113 36 22 Sep 10 Apr 20 May 2 APR 17 145 60 20 17 16 15 15 15 14 14 14 16 14 14 13 13 13 13 13 14 13 13 13 14 14 14 14 14 14 —— 608 20.3 145 13 1210 1.11 1.24 MAY 14 14 14 13 13 13 15 17 19 25 18 19 26 25 29 36 44 34 28 24 22 20 26 26 27 25 40 33 43 66 25 793 25.6 66 13 1570 1.40 1.61 JUN 26 40 253 33 24 21 20 24 21 15 15 15 16 21 14 12 11 11 14 26 18 16 15 15 14 14 13 13 13 11 —— 774 25.8 253 11 1540 1.41 1.57 JUL 10 10 11 13 19 18 17 18 19 15 12 12 20 19 19 30 43 24 50 95 231 53 47 33 26 26 29 178 48 39 46 1230 39.7 231 10 2440 2.17 2.50 AUG e35 e30 e32 e29 e26 e25 e21 e23 e25 e56 e64 e40 e35 e26 e24 e31 e33 el63 e57 e35 e28 e580 102 134 75 38 46 39 42 33 36 1963 63.3 580 21 3890 3.46 3.99 SKf 28 28 25 22 20 18 18 17 17 16 15 16 16 23 73 24 19 19 18 16 94 198 111 60 41 78 57 36 34 49 —— 1206 40.2 198 15 2390 2.20 2.45 , BY WATER YEAR (WY) 21.7 43.4 1976 9.98 1968 FOR 1997 13587 37 580 10 12 2410 9 9 26950 2 27 61 26 14 50.5 172 1969 10.3 1974 WATER YEAR .2 Aug 22 Jul 1 Jun 27 Aug 22 .06 Aug 22 .8 Jul 1 .03 .62 64.3 200 1979 13.1 1974 64.4 164 1979 14.1 1974 69.5 231 1979 17.2 1994 WATER YEARS 1966 - 56.2 117 19.8 4780 4.8 5.0 30900 unknown 4.6 40730 3.07 41.74 96 28 12 Sep 16 May 9 Apr 10 Jan 5 Jan 5 May 13 87.7 314 1979 12.1 1967 1997 1979 1994 1975 1968 1968 1992 1992 1968 e Estimated RIO GRANDE DE PATILLAS BASIN 50092000 RIO GRANDE DE PATILLAS NEAR PATILLAS, PR—Continued WATER-QUALITY RECORDS 361 PERIOD OF RECORD.—Water years 1960 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1025 37 177 7.4 24.5 8.6 7.7 90 <10 2100 620 1110 26 154 6.7 23.5 0.70 7.7 89 <10 K660 3100 1135 27 174 6.9 26.5 41 6.8 85 <10 K8200 5900 1110 64 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 53 — 55 48 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 <0.20 <0.20 <0.20 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 13 — 13 11 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 25 — 21 24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.32 <0.20 0.22 0.33 115 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.1 — 5.3 4.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 115 — 118 120 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 1.4 0.45 0.97 1.5 6.8 26.5 46 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 14 — 13 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 11.4 — 8.60 21.0 PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 <0.020 <0.020 <0.020 SODIUM AD- SORP- TION RATIO (00931) 0.8 — 0.8 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 20 2 39 26 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 0.90 — 0.79 0.60 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.150 0.030 0.030 0.180 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 __ 7.5 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 56 56 67 34 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 — 94 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.150 0.030 0.040 0.180 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — <10 K1700 620 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 11 — 12 11 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 <0.010 0.020 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 12 — 12 12 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K • non-ideal count 362 DATE RIO GRANDE DE PATILLAS BASIN 50092000 RIO GRANDE DE PATILLAS NEAR PATILLAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MANGA- IRON, LEAD, NESE, MERCURY TOTAL TOTAL TOTAL TOTAL RECOV- RECOV- RECOV- RECOV- ERABLE ERABLE ERABLE ERABLE (UG/L (UG/L (UG/L (UG/L AS FE) AS PB) AS MN) AS HG) (01045) (01051) (01055) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SOB- STANCE (MG/L) (38260) OCT 1996 29... FEB 1997 12... HAY 13... AUG 25... 910 1500 100 <0.10 110 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 RIO PATILLAS BASIN 50093045 LAGO PATILLAS AT DAMSITE NEAR PATILLAS, PR 363 LOCATION.—Lat 18°01'15" / long 66°01'19", Hydrologic Unit 21010004, on right bank, in a concrete tower at Damsite, 1.05 mi (1.69 km) northeast from Patillas plaza, 0.45 mi (0.72 km) northeast from Escuela Segunda Unidad de Real and 2.30 mi (3.70 km) from Escuela Segunda Unidad de Jesus Maria Rodriguez. DRAINAGE AREA.—25.2 mi 1 (65.3 km1 ). ELEVATION RECORDS PERIOD OF RECORD.--March 1995 to current year. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Patillas was completed in 1914. The dam is a semihydraulic earthfill structure about 147 ft (45 m) height, a top width of 15 ft (4.6 m), maximum pool elevation of 230 ft (70.1 m), a base width of 625 ft (190 m), a crest lenght of 1,067 ft (325 m) and has maximum pool storage of 17,073 ac-ft (21.05 hm} ) . The Patillas Dam is owned by the Puerto Rico Electric Power Authority (P.R.E.P.A) and its primary purpose is for irrigation of lands served by the Patillas irrigation canal. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 225.92 ft (68.86 m) Sept. 10, 1996; minimum elevation, 211.19 ft (64.37 m), May 29, 1995, July 19, 1997. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximun elevation, 222.22 ft (67.73 m), Nov. 12; minimum elevation, 211.19 ft (64.37 m), July 19. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 143 190 Contents, in acre-feet 0 5,492 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN Elevation, in feet 200 225 230 Contents, in acre-feet 7,752 15,005 16,773 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES NOV DEC JAN 221.41 A 221.90 221.77 221.76 221.90 221.84 221.73 220.92 220.98 220.79 220.54 220.27 221.03 221.29 221.45 221.53 221.77 221.98 221.99 221.87 221.70 221.60 221.51 221.48 221.56 221.62 221.85 221.91 221.92 222.02 222.02 220.27 1996 1997 221.97 221.79 221.56 221.63 221.56 221.49 221.44 221.42 221.51 221.47 222.05 221.98 220.88 220.69 220.45 220.17 219.92 219.66 219.45 219.25 219.26 219.47 219.75 219.97 220.11 220.21 220.31 220.44 220.55 220.72 --- 222.05 219.25 MAX 223.60 MAX 222.05 220.83 220.91 220.95 220.92 220.86 220.81 220.80 220.78 220.76 220.72 220.81 220.78 220.71 220.67 220.64 220.61 220.45 220.42 220.37 220.33 220.31 220.29 220.23 220.23 220.23 A 220.15 220.05 220.15 220.38 220.37 220.95 220.05 MIN 216 MIN 211 220.34 220.32 220.28 220.26 220.23 220.19 220.13 220.06 219.97 219.79 220.11 220.11 220.03 219.97 219.93 219.86 219.75 219.69 219.59 219.56 219.55 220.15 220.20 220.22 220.26 220.30 220.23 220.28 220.23 220.20 220.20 220.34 219.55 .02 .26 FEB 220.80 221.06 221.24 221.31 221.61 221.81 221.87 221.85 221.90 221.86 221.81 221.77 221.85 221.08 220.84 220.86 220.86 220.88 220.96 220.98 221.29 221.42 221.57 221.61 221.61 221.95 221.87 221.74 221.95 220.80 MAR 221.61 221.50 221.44 221.39 221.35 221.29 221.26 221.25 221.21 221.10 221.01 220.94 220.83 220.83 220.89 220.98 220.65 220.87 220.83 220.72 220.62 220.49 220.42 220.31 220.15 220.10 219.98 219.94 219.84 219.75 219.69 221.61 219.69 APR 219.62 220.43 220.64 220.65 220.61 220.53 220.45 220.40 220.31 220.23 220.12 220.04 219.98 219.85 219.73 219.61 219.50 219.38 219.24 219.10 218.99 218.86 218.72 218.54 218.43 218.27 218.14 218.05 217.88 217.71 220.65 217.71 MAY 217.58 217.47 217.30 217.15 216.99 216.88 216.74 216.67 216.56 216.49 216.39 216.29 216.24 216.12 216.03 215.97 215.93 215.86 215.70 215.59 215.43 215.26 215.08 214.98 214.88 214.69 214.85 214.86 214.97 215.24 215.26 217.58 214.69 JUN 215.25 215.31 215.82 215.99 215.94 215.85 A A A A A A A A A A 214.54 214.35 214.28 214.34 214.31 214.22 214.07 213.92 213.83 213.67 213.59 213.47 213.35 213.21 215.99 213.21 JUL 213.11 212.98 212.79 212.66 212.56 212.50 212.34 212.24 212.14 212.00 211.83 211.66 211.52 211.36 211.30 211.30 211.30 211.26 211.32 211.79 212.84 213.04 213.25 213.37 213.42 213.52 213.54 214.47 214.60 214.69 214.80 214.80 211.26 AUG 214.80 214.77 214.73 214.73 214.69 214.59 214.51 214.44 214.43 214.60 214.73 214.77 214.81 214.77 214.73 214.78 214.98 215.94 216.01 215.99 215.93 219.77 220.34 220.91 221.22 221.34 221.62 221.75 221.83 221.78 221.79 221.83 214.43 SEP 221.69 221.62 221.49 221.41 221.56 A A A A A A A A A A A A A A A A A A A A A A A A A 221.69 221.41 A No gage-height record 364 THIS PAGE WAS LEFT BLANK INTENTIONALLY AI8GNIT0 EXPLANATION A 1080 SURFACE-WATER STATION AND NUMBER V 1085 QUAUTY-OF-WATER STATION AND NUMBER A 1109 DAILY SEDIMENT STATION AND NUMBER 87 WELL AND WELL NUMBER 1113 LAKE-ELEVATION STATION AND NUMBER CAYE V boundary Islarx: CARIBBEAN SEA 4- 0123456 KILOMETERS 01234 MILES -Wop oreo Figure 22.-South coast river basins the Rio Salinas to Rio Jacaguas basins. 366 RIO SALINAS BASIN 50100200 RIO LAPA NEAR RABO DEL BUEY, PR LOCATION.—Lat 18°03'36", long 66°14'28", Hydrologic Unit 21010004, on left bank, at bridge on Highway 1, Km 9.7, 1.5 mi (2.4 km) north of Rabo del Busy, and 4.4 mi (7.1 km) northeast of salinas Plaza. DRAINAGE AREA.--9.92 mi 1 (25.69 tan'). PERIOD OF RECORD.—1953-63 (annual low-flow measurements only), September 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 394 ft (120 m), from topographic map. REMARKS.—Records poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT DEC JAN FEE APR JUN JUL AUG SEP 1 5.1 1.2 2 4.1 1.1 3 3.8 .89 4 3.8 .80 5 3.8 .59 6 6.3 .66 7 4.8 .51 8 4.7 .32 9 5.1 .37 10 5.7 .49 11 6.1 6.5 12 6.1 e6.7 13 6.2 e5.4 14 7.0 e3.6 15 7.6 e2.8 16 7.8 e2.1 17 7.9 e2.4 18 8.1 e2.2 19 8.9 e2.1 20 9.4 e2.5 21 9.2 66.0 22 8.7 e4.0 23 7.6 63.6 24 5.5 e3.2 25 3.6 e2.7 26 3.3 e2.0 27 4.3 el. 8 28 2.8 e2.0 29 2.0 e2.2 30 1.2 e2.4 31 .95 —— TOTAL 171.45 73.13 MEAN 5.53 2.44 MAX 9.4 6.7 MIN .95 .32 AC-FT 340 145 CFSM .55 .24 IN. .64 .27 STATISTICS OF MONTHLY MEAN MEAN 13.5 5.31 MAX 76.1 28.4 (WY) 1991 1991 MIN 1.46 1.07 (WY) 1992 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 62.8 62.5 e2.5 e2.5 e2.5 e2.5 e2.7 e2.3 el. 9 el. 8 e5.4 e3.0 e2.4 e2.2 62.1 el. 7 el. 5 el. 3 el. 2 el.l el.l el. 3 el. 2 el. 2 el. 2 el.l el. 2 el.l el.l e2.4 e2.0 60.8 1.96 5.4 1.1 121 .20 .23 el. 3 el.l el.l e.96 e.86 e.94 e.96 e.78 e.82 e.86 el. 3 el. 8 el.l e.96 e.86 e.86 e.86 e.78 e.82 e.78 e.78 e3.6 el. 8 e.86 e.70 e.60 e.47 e.40 e.40 e.40 e.40 30.21 .97 3.6 .40 60 .10 .11 DATA FOR WATER 2.06 6.09 1991 .75 1995 FOR 8.86 68.8 1992 .47 1994 el.O el. 3 e.80 e.58 e.50 e.68 a. 56 e.50 e.50 e.54 e.56 e.50 e2.0 el. 8 el. 2 a. 76 a. 62 e.58 e.56 e.56 a. 88 el. 4 el.l e.80 el. 3 e5.4 e4.8 el.O —— —— 32.78 1.17 5.4 .50 65 .12 .12 YEARS 1988 2.75 12.4 1991 .49 1990 e.82 e.70 a. 52 e.70 e.70 a. 66 e.54 e.52 a. 60 a. 60 e.37 a. 30 a. 28 a. 35 e.30 a. 45 a. 66 e.50 el.O el.l el.l el. 2 el.O el. 2 a. 84 e.68 e.84 a. 74 el.O a. 90 e.74 21.91 .71 1.2 .28 43 .07 .08 - 1997 .94 2.08 1992 .44 1990 1996 CALENDAR YEAR 3176. 8. 1900 . . 6300 . 11. 7. 1. . 39 68 03 05 87 82 6 1 12 Sap 10 May 25 May 29 a. 45 a. 46 el. 2 e.80 e.52 a. 45 e.33 6.31 .33 .33 .33 .33 .34 .41 .43 .44 .57 .56 .56 .55 .87 .52 .33 .32 .28 .26 .26 .23 .22 .23 —— 13.22 .44 1.2 .22 26 .04 .05 .23 .23 .23 .23 .23 .20 .18 .37 .24 .32 .20 .36 .23 .20 .16 .21 .14 .13 .11 .08 .07 .09 .09 .09 .09 .09 .09 .09 .09 .08 .09 5.24 .17 .37 .07 10 .02 .02 .08 .09 .09 .08 .09 .09 .09 .09 .08 .08 .08 .08 .08 .07 .07 .07 .06 .06 .06 .06 .05 .05 .05 .04 .04 .04 .04 .03 .03 .03 —— 1.95 .065 .09 .03 3.9 .01 .01 .03 .03 .03 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .03 .03 .04 .03 .03 .05 .05 .05 .05 .06 .06 .06 .06 .07 .07 .07 .08 1.20 .039 .08 .02 2.4 .00 .00 .08 .07 .08 .08 .07 .07 .07 .07 .07 .08 .13 .15 .20 .17 .13 .14 .19 .18 .14 .12 .17 1.2 .62 .34 .31 .21 .24 .26 .21 .18 .17 6.20 .20 1.2 .07 12 .02 .02 .17 .16 .13 .09 .08 .07 .05 .03 .03 .02 .01 .02 .02 .01 .01 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .60 .03 .01 .01 .01 —— 1.56 .052 .60 .00 3.1 .01 .01 , BY WATER YEAR (WY) 1.03 3.07 1992 .28 1990 4.68 36.6 1992 .086 1994 2.32 10.4 1993 .036 1994 FOR 1997 WATER YEAR 419.65 1.15 9.4 .00 .00 unknown unknown 832 .11 1.56 3.6 .46 .03 Oct 20 Sep 16 Sep 16 Nov 11 Nov 11 1.92 7.80 1993 .009 1994 WATER 5 11 1900 18100 18 3850 7 5 1 2.36 6.06 1990 .001 1994 YEARS 1988 - .31 .2 .57 Sep 10 .00 Jun 24 .00 Jul 21 Sep 10 .65 Sep 10 .53 .22 .4 .0 .10 17.9 81.2 1996 .052 1997 1997 1991 1994 1996 1994 1994 1996 1996 e Estimated RIO SALINAS BASIN 50100450 RIO MAJADA AT LA PLENA, PR 367 LOCATION.—Lat 18«02'40", long 66°12'27", Hydrologic Unit 21010004, on right bank, upstream side of bridge on Hwy 712, about 0.3 mi (0.5 km) southwest of La Plena. DRAINAGE AREA.—16.7 mi* (43.3 km*). PERIOD OF RECORD.—January 1973 to April 1979 (montly measurements only), September 1988 to current year. GAGE.—Water-stage recorder. Elevation of gage is 410 ft (125 m), from topographic map. REMARKS.-Records fair except those for estimated daily discharges, which are poor. Some regulation at low flow upstream from station by local residents for agricultural purposes. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB APR MAY JUN JUL AUG SEP 1 16 5.4 2 13 6.0 3 12 5.1 4 11 .9 5 9.8 .3 6 11 .4 7 8.4 .9 8 7.4 .3 9 6.4 .2 10 7.9 3.0 11 10 14 12 7.1 22 13 6.0 8.2 14 6.3 3.5 15 6.0 2.8 16 6.2 2.1 17 6.1 2.4 18 8.0 2.2 19 9.9 2.1 20 6.4 2.7 21 5.9 7.0 22 5.5 5.1 23 4.6 3.3 24 4.4 2.9 25 4.0 2.4 26 5.0 1.6 27 8.0 1.4 28 6.8 1.6 29 6.4 1.7 30 6.5 1.9 31 6.0 TOTAL 238.0 137.4 MEAN 7.68 4.58 MAX 16 22 MIN 4.0 1.4 AC-FT 472 273 CFSM .46 .27 IN. .53 .31 STATISTICS OF MONTHLY MEAN MEAN 12 . 5 6 . 53 MAX 76.4 25.2 (WY) 1991 1991 MIN 1.43 1.53 (WY) 1992 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 2.2 2.0 2.0 2.0 2.0 2.0 2.1 1.8 1.5 1.4 4.3 2.4 1.6 1.3 1.2 1.0 .86 .78 .71 .67 .67 .74 .73 .71 .71 .66 .70 .69 .68 1.4 1.2 42.71 1.38 4.3 .66 85 .08 .10 .76 .64 .63 .58 .52 .56 .51 .47 .49 .52 .77 1.1 .63 .58 .52 .52 .52 .47 .49 .47 .47 2.2 1.1 .51 .42 .36 .28 .24 .24 .24 .24 18.05 .58 2.2 .24 36 .03 .04 .59 .76 .48 .35 .30 .41 .33 .30 .30 .32 .33 .30 1.2 1.1 .55 .46 .36 .35 .34 .34 .55 .84 .69 .48 .80 3.3 2.9 1.9 —— —— 20.93 .75 3.3 .30 42 .04 .05 DATA FOR WATER YEARS 1973 3.24 9.67 1991 .62 1995 FOR 9.74 68.8 1992 .37 1995 3.07 12.1 1991 .63 1990 1.5 1.3 .96 1.3 1.3 1.2 1.0 .96 1.1 1.1 .70 .54 .52 .63 .55 .82 1.2 .90 1.8 2.0 2.1 2.2 1.9 2.3 1.6 1.3 1.6 1.4 1.9 1.7 1.4 40.78 1.32 2.3 .52 81 .08 .09 - 1997 1.92 3.92 1991 .59 1990 1996 CALENDAR YEAR 4464.33 12.2 2270 .51 .69 8850 .73 9.94 10 2.4 .86 Sep 10 May 22 May 6 .86 .88 2.2 1.5 1.0 .85 .62 .57 .54 .66 .52 .52 .61 .57 .64 1.2 .85 .66 .37 .29 .29 .32 .29 .29 .29 .35 .32 .31 .32 .38 —— 19.07 .64 2.2 .29 38 .04 .04 .47 .58 .52 .49 .87 .53 .66 1.4 .99 1.0 1.1 1.2 1.1 1.2 1.3 1.2 1.7 1.1 ,.62 .38 .30 .39 .31 .38 .58 .54 .33 .33 .30 .28 .35 22.50 3. .73 1.7 .28 45 7 .04 .05 33 .04 21 .03 23 .02 30 .02 47 .02 30 .01 27 .01 17 .01 17 .02 09 .01 10 .03 06 .01 06 .01 05 .01 06 .02 06 .02 04 .02 02 .01 04 .00 04 .00 05 .00 04 .00 02 .00 05 .00 06 .00 06 .00 05 .00 05 .01 04 .01 05 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .02 .03 .02 .02 .02 .03 .03 .02 .02 .02 .17 .08 .05 .04 .03 .04 .04 .03 .03 .02 .02 .02 .01 .01 .01 .01 .01 .01 .00 .00 .01 .01 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .09 .00 .00 .00 .00 .02 54 0.36 0.88 0.23 12 .012 .028 .008 47 .04 .17 .09 02 .00 .01 .00 .0 .7 1.7 .5 01 .00 .00 .00 01 .00 .00 .00 , BY WATER YEAR (WY) 1.43 3.69 1992 .30 1995 3.78 3. 25.5 12 18 3.21 2.17 19.9 .1 12.9 7.74 109 1992 1992 1993 1992 1996 .21 .042 .012 .010 .008 1994 1994 1997 1994 1997 FOR 1997 WATER YEAR 544.45 1.49 22 .00 .00 47 3.51 1080 .089 1.21 4.9 .52 .01 NOV 12 Jul 19 Jul 19 NOV 11 Nov 11 WATER YEARS 1973 - 1997 5.90 12.1 1992 .81 1994 2270 Sep 10 1996 .00 Oct 3 1994 .00 Oct 8 1994 17700 Sep 10 1996 19.69 Sep 10 1996 4270 .35 4.80 7.8 1.6 .15 e Estimated 368 RIO COAMO BASIN 50106100 RIO COAMO AT COAMO, PR LOCATION.—Lat 18°05'00", long 66°21'16", Hydrologic Unit 21010004, on Highway 14 bridge, 0.8 mi (1.3 km) northeast from Parque Atletico, 1.2 mi (1.9 km) southeast from (W.C.P.R.) Antena de Radio. DRAINAGE AREA.—3.5 mi* (112.7 km*). PERIOD OF RECORD.—January 1987 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 335 ft (110 m), from topographic map. REMARKS.—Records poor. Low flow is affected by domestic discharges about 200 ft (65.6 m), upstream from gaging station. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT JAN FEB MAR APR MAY JUN JUL AUG SEP 1 21 19 2 19 20 3 28 21 4 27 23 5 22 22 6 47 21 7 34 21 8 27 18 9 27 25 10 29 37 11 30 30 12 25 25 13 26 21 14 24 18 15 22 16 16 24 18 17 36 66 18 35 49 19 47 45 20 34 61 21 38 112 22 31 51 23 28 58 24 25 51 25 23 34 26 24 25 27 27 18 28 29 17 29 28 15 30 37 14 31 22 TOTAL 896 971 MEAN 28.9 32.4 MAX 47 112 MIN 19 14 AC -FT 1780 1930 CFSM .66 .74 IN. .77 .83 STATISTICS OF MONTHLY MEAN MEAN 55.5 27.2 MAX 274 62.9 (WY) 1991 1988 MIN 10.3 4.91 (WY) 1989 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 14 12 14 16 17 16 15 15 14 14 15 15 12 13 15 14 13 11 11 11 11 11 11 10 10 10 10 11 13 35 13 422 13.6 35 10 837 .31 .36 13 20 16 16 12 12 10 10 9.9 9.3 8.7 9.3 7.7 6.8 7.7 7.7 7.2 6.8 6.5 7.9 7.7 15 14 11 10 9.6 8.6 8.1 7.7 7.0 7.3 310.5 10.0 20 6.5 616 .23 .27 DATA FOR WATER 17.7 83.8 1988 3.72 1989 FOR 18.4 79.0 1992 2.71 1995 7.8 10 8.4 7.6 7.3 7.3 7.2 7.1 7.2 7.2 6.9 6.7 6.9 6.6 5.8 5.9 6.3 5.8 5.9 6.1 5.8 6.1 6.3 5.8 5.4 6.0 6.0 5.3 —— 186.7 6.67 10 5.3 370 .15 .16 YEARS 1987 9.26 17.0 1988 3.17 1989 5.4 5.8 5.4 5.5 5.0 4.9 5.1 5.1 5.2 5.0 .6 .6 .7 .5 .8 .6 .8 .7 5.1 4.4 4.2 3.9 3.9 4.7 3.8 3.6 5.3 13 e8.8 6.5 5.6 162.5 5.24 13 3.6 322 .12 .14 - 1997 5.86 9.79 1988 3.09 1987 1996 CALENDAR YEAR 7560. 20. 1440 1. 1. 15000 . 6. 35 8. 4. 1 7 Sep 10 3 Jul 6 6 Jun 30 47 47 5 1 5.3 18 15 6.5 5.5 5.2 5.1 5.1 .6 .6 .5 .1 .1 3.7 3.5 3.6 3.4 3.7 3.7 4.0 4.0 3.7 3.8 3.6 3.7 3.8 3.5 3.4 3.1 3.0 —— 148.8 4.96 18 3.0 295 .11 .13 3.1 3.0 3.3 3.2 3.5 3.1 2.9 2.7 3.0 3.1 3.0 3.2 2.8 2.8 2.9 3.1 3.9 4.4 4.0 3.5 3.2 3.8 3.5 3.3 3.2 3.9 4.6 4.1 3.9 3.5 3.3 104.8 3.38 4.6 2.7 208 .08 .09 3.7 3.5 3.4 2.7 2.5 2.5 2.9 3.4 3.4 3.8 4.5 4.0 3.2 2.8 2.5 2.8 2.1 2.2 2.6 2.5 2.9 2.7 2.6 2.9 2.3 2.2 2.3 2.9 2.5 2.7 —— 87.0 2.90 4.5 2.1 173 .07 .07 2.5 2.1 2.2 2.1 2.2 2.2 1.9 2.1 2.6 2.5 1.9 1.9 1.9 1.9 2.0 2.1 2.0 2.4 2.8 5.1 4.2 3.3 3.1 2.8 3.0 2.5 2.8 2.9 2.8 2.5 1.9 78.2 2.52 5.1 1.9 155 .06 .07 2.0 2.1 2.8 2.7 1.7 2.0 1.8 1.9 5.1 3.8 2.4 2.2 79 4.3 2.2 2.0 2.0 1.8 1.7 1.7 1.6 1.8 1.8 2.2 2.1 1.7 1.6 1.8 1.7 1.7 1.6 144.8 4.67 79 1.6 287 .11 .12 1.8 1.7 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.4 1.4 1.5 1.7 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.5 1.6 1.5 1.7 1.6 2.1 19 7.5 —— 69.3 2.31 19 1.4 137 .05 .06 , BY WATER YEAR (WY) 10.5 27.6 1987 2.49 1995 FOR 1997 3581 9 112 1 1 977 7 7100 3 25 4 1 15.8 69.6 1992 1.66 1989 WATER YEAR .6 .81 Nov 21 .4 Sep 12 .4 Sep 16 Nov 21 .18 Nov 21 .23 .06 .7 .8 14.2 76.1 1987 1.99 1989 7.27 15.5 1988 .78 1989 WATER 17. 36. 4. 1580 . . 51600 25. 12850 . 5. 33 6. 2. 8.75 23.3 1990 1.28 1994 YEARS 1987 - 7 8 52 jan 5 67 Aug 2 70 Jul 27 Jan 8 67 Jan 8 41 54 8 1 28.8 92.8 1996 1.61 1994 1997 1991 1994 1992 1989 1989 1992 1992 e Estimated RIO COAHO BASIN 369 50106500 RIO COAHO NEAR COAHO, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°03'52", long 66°22'10", Hydrologic Unit 21010004, on Highway 153 bridge, 0.4 mi (0.6 km) above Rio de la Mina, and 1.8 mi (2.9 km) south of Coamo plaza. DRAINAGE AREA.--46.0 mi' (119.1 km'). PERIOD OF RECORD.—Water years 1978 to current year. WATER-QUALITY RECORDS, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 24 FEB 26 MAY 21 SEP 03 DATE 1996 ... 1997 ... ... ... DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1035 19 0915 8 0905 4 1145 2 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 240 — 200 230 .4 .4 .2 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 63 -- 70 59 564 620 612 607 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 19 _- 6.8 20 8.2 7.3 7.2 7.5 28.0 25.0 27.0 33.0 0.70 0.30 1.5 1.5 SODIUM POTAS- SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 31 — 14 35 AD- SORP- TION RATIO (00931) 0.9 — 0.4 1 SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.9 — 1.4 2.7 8.5 8.8 8.4 8.0 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 200 250 230 250 106 104 104 113 <10 <10 <10 <10 K730 K91 3100 K170 K140 K110 370 K1800 CHLO- SULFATE RIDE, SULFIDE TOTAL (MG/L AS S) (00745) <0.5 __ <0.5 — DIS- DIS- SOLVED SOLVED (MG/L AS SO4) (00945) 36 — 7.9 33 (MG/L AS CL) (00940) 37 — 25 39 DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — <0.10 0.18 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 31 — 6.2 36 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 340 -- 269 374 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 17.4 -- 3.19 2.26 RESIDUE TOTAL AT 105 DEG. C, SUS- FENDED (MG/L) (00530) 3 <1 2 4 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 2.30 2.00 0.830 0.960 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.020 0.020 NITRO- NITRO- NITRO- GEN, GEN/ GEN/ N02+N03 AMMONIA ORGANIC TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L AS N) AS N) AS N) (00630) (00610) (00605) 2.30 0.020 0.43 2.00 0.020 0.24 0.030 0.030 <0.20 0.980 0.040 0.20 DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.45 0.26 <0.20 0.24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.8 2.3 1.0 1.2 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 12 10 4.6 5.4 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.150 0.100 0.080 0.160 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 70 — 20 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 __ <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 20 -- <10 — K - non-ideal count 370 RIO COMIO BASIN 50106500 RIO COAMO NEAR COAMO, PR—Continued WATER-QUALITY RECORDS, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... IRON, TOTAL RECOV- ERABLE (UG/L AS PE) 170 110 MANOA- LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) TOTAL RECOV- ERABLE (UG/L AS MN) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) SILVER, ZINC, SELE- NIUM, TOTAL (UO/L AS SE) TOTAL RECOV- ERABLE (UO/L AS AG) TOTAL RECOV- ERABLE (UO/L AS ZN) CYANIDE TOTAL PHENOLS (MO/L TOTAL AS CN) (UO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 20 <0.10 30 <0.10 <1 <1 <1 <1 <0.010 <0.010 METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) <0.01 <0.01 RIO DESCALABRADO BASIN 50108000 RIO DESCALABRADO NEAR LOS LLANOS, PR 371 LOCATION.--Lat 18°03'08", long 66°25'34", Hydrologic Unit 21010004, at bridge on Highway 14, 1.5 mi (2.4 km) west of Los Llanos, and 5.3 mi (8.5 km) east of JUana Diaz. DRAINAGE AREA.—12.9 mi* (33.4 tan') - PERIOD OP RECORD.—1959-65 (annual low-flow measurements only), 1965 (annual maximum discharge), January 1966 to June 1969, July to December 1969 (maximum discharge only), February 1984 to current year. GAGE.—Water-stage recorder. Elevation of gage is 220 ft (67 m), from topographic map. REMARKS.--Records poor. Some regulation at low flow by local resident upstream from station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY OCT NOV 1 ell e7 . 0 2 elO e6.2 3 e9.2 e5.8 4 9.2 e5.4 5 8.8 e5 . 0 6 8.1 e4.7 7 7.6 4.5 8 7.2 4.2 9 6.3 30 10 6.1 16 11 5.9 8.9 12 4.7 8.8 13 4.3 6.8 14 3.9 5.2 15 3.7 5.4 16 3.3 19 17 3.1 e97 18 3.1 e!8 19 36 13 20 23 22 21 53 e71 22 73 e!9 23 22 e!06 24 12 e46 25 9.4 13 26 7.9 10 27 7.6 9.4 28 10 8.4 29 9.5 8.0 30 14 7.7 31 elO —— TOTAL 402.9 591.4 MEAN 13.0 19.7 MAX 73 106 MIN 3.1 4.2 AC-FT 799 1170 CFSM 1.01 1.53 IN. 1.16 1.71 STATISTICS OF MONTHLY MEAN MEAN 26.6 14.8 MAX 117 41.0 (WY) 1986 1985 MIN 2.02 1.04 (WY) 1968 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 8.4 8.1 7.6 7.5 7.3 6.6 6.3 6.6 6.7 6.3 6.3 5.8 5.7 6.3 11 11 5.5 4.9 4.1 3.9 4.2 4.0 3.7 3.5 3.4 3.1 3.0 4.8 5.5 5.5 5.1 181.7 5.86 11 3.0 360 .45 .52 JAN 4.5 8.6 13 7.4 3.7 3.5 3.2 4.4 5.8 3.2 4.9 3.8 3.4 3.6 3.4 3.3 3.5 3.5 3.3 3.1 3.1 4.5 3.1 2.9 2.6 2.8 2.4 2.6 2.5 2.3 2.7 124.6 4.02 13 2.3 247 .31 .36 DAILY FEB 2.4 2.3 2.2 2.2 2.1 1.9 2.1 1.9 1.8 1.8 1.9 1.8 1.6 1.5 1.7 1.7 1.6 1.6 1.5 1.6 1.4 1.4 1.4 1.5 1.3 1.1 1.2 1.2 —— —— —— 47.7 1.70 2.4 1.1 95 .13 .14 DATA FOR WATER YEARS 1966 5.02 24.5 1988 .19 1968 FOR 4.84 36.4 1992 .057 1968 3.64 23.9 1995 .020 1968 MEAN VALUES MAR 1.1 1.0 .95 .95 .88 .83 .87 .85 .83 .73 .69 .73 .73 .77 .77 1.2 1.3 .86 .56 .55 .57 .52 .54 .57 .62 .55 .46 .35 .42 .60 .62 22.97 .74 1.3 .35 46 .06 .07 - 1997 1.97 8.93 1996 .012 1968 1996 CALENDAR YEAR 15617.79 42.7 10000 .34 .38 30980 3.31 45.04 27 4.0 .65 Sep 10 Jan 24 Jan 22 APR .68 .55 .47 .56 .56 .56 .53 .58 .49 .56 .57 .53 .54 .51 .49 .51 .47 .48 .51 .52 .52 .46 .47 .51 .47 .49 .45 .44 .45 .40 —— 15.33 .51 .68 .40 30 .04 .04 MAY .36 .32 .32 .31 .31 .32 .30 .30 .31 .26 .28 .28 .28 .29 .29 .24 .25 .24 .25 .25 .21 .17 .17 .19 .19 .18 .17 .18 .16 .17 .16 7.71 .25 .36 .16 15 .02 .02 JUN .18 .15 .16 .15 .15 .15 .16 .15 .13 .14 .14 .15 .12 .13 .13 .13 .13 .14 .12 .14 .15 .18 .25 .38 .77 .15 .43 .39 .30 .14 —— 5.99 .20 .77 .12 12 .02 .02 JUL .13 .14 .16 .18 .32 .16 .30 .17 .14 .31 .34 .25 .38 .18 .57 .20 1.2 .28 .15 .15 .15 .15 .21 .24 .24 .39 .68 .30 .85 .50 .52 9.94 .32 1.2 .13 20 .02 .03 AUG 1.2 2.7 1.5 1.8 2.3 2.6 3.8 1.5 2.3 .33 e.30 e.18 e6.4 e.35 e.18 e.16 e.16 e.15 e.14 e.14 e.13 e.15 e.15 e.18 e.17 e.14 e.13 e.15 e.14 e.14 e.13 29.80 .96 6.4 .13 59 .07 .09 SEP e.15 e.14 e.12 e.12 e.12 e.12 e.12 e.12 e.12 e.12 e.12 e.25 .40 .57 .43 1.3 .47 .14 .13 .11 .23 .85 .25 .17 .19 .57 .45 3.8 98 20—— 129.68 4.32 98 .11 257 .34 .37 , BY WATER YEAR (WY) 4.22 18.8 1985 .000 1968 FOR 1997 1569 4 106 1530 7 3110 4 8 14.8 62.2 1985 .032 1968 WATER YEAR .72 .30 NOV 23 .11 Sep 20 . 12 Sep 3 Sep 29 .77 Jul 22 .33 .53 .8 .77 .15 4.98 25.2 1987 .000 1967 2.69 10.5 1991 .000 1967 WATER 10 41 1 10000 30000 24 7830 11 14 1 3.98 13.1 1996 .19 1990 YEARS 1966 .8 .7 .69 .00 .00 .37 .84 .38 .3 .05 Sep Jun Jun Oct Oct 34.8 395 1996 .063 1967 - 1997 1996 1994 10 1996 22 1966 22 1966 7 1985 7 1985 e Estimated 372 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR LOCATION.--Lat 18°07'37", long 66°27'24", Hydrologic Unit 21010004, on right bank, off a dirt road about 0.3 mi (0.5 tan) from road 553, 2.4 mi (3.9 tan) southeast from Villalba plaza, and 0.2 mi (0.3 tan) downstream from confluence with Quebrada Limon. DRAINAGE AREA.—7.64 mi 1 (19.79 tan'). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--April 1989 to current year. GAGE.—Water stage recorder. Elevation of gage is 525 ft (160 m ), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor, satellite telemetry at station. Gage-height and precipitation DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN MAX MIN AC-FT CFSM IN. el6 el4 e21 e22 19 24 26 21 18 18 17 n!6 15 16 15 13 13 14 28 17 53 40 39 28 23 21 21 20 21 30 21 680 21.9 53 13 1350 1.54 1.78 STATISTICS OF MEAN MAX (WY) MIN (WY) 42.2 109 1991 4.61 1992 18 18 17 17 17 16 16 16 33 24 41 29 21 17 16 24 54 57 44 47 69 46 79 73 39 29 25 21 20 19 —— 962 32.1 79 16 1910 2.26 2.52 19 17 17 17 16 15 14 13 13 13 17 13 12 11 11 9.9 9.0 8.6 8.5 8.0 7.6 7.3 7.0 6.8 6.8 6.6 6.8 6.8 9.3 7.8 7.0 341.8 11.0 19 6.6 678 .78 .90 MONTHLY MEAN DATA 17.1 40.1 1991 2.19 1992 6.98 12.4 1993 1.42 1992 7.0 10 8.9 11 7.0 6.3 6.6 6.5 6.3 6.4 6.8 7.1 7.3 20 12 6.8 6.2 7.1 7.1 7.1 7.2 11 12 9.1 8.6 7.2 6.3 5.7 5.5 5.2 5.2 246.5 7.95 20 5.2 489 .56 .65 FOR WATER 9.97 43.1 1992 1.79 1995 5.6 5.3 4.7 4.5 4.5 .3 .4 .4 .2 .1 4.0 3.8 3.8 3.7 3.5 3.6 3.3 3.3 3.4 3.3 3.0 3.3 3.1 3.0 3.0 3.1 3.1 3.0 ___ 106.3 3.80 5.6 3.0 211 .27 .28 YEARS 1989 5.45 12.6 1996 2.38 1990 3.0 3.0 2.9 3.0 3.0 2.9 2.9 2.9 2.8 2.9 2.7 2.6 2.6 2.6 2.6 2.6 2.5 2.4 2.6 2.5 2.4 2.4 2.5 2.5 2.4 2.4 2.6 2.8 4.2 3.2 2.5 84.9 2.74 4.2 2.4 168 .19 .22 - 1997, 3.49 5.01 1996 1.67 1990 2.4 2.6 2.6 2.3 2.2 2.0 1.9 2.0 2.1 2.0 1.8 1.8 1.8 1.9 1.9 1.7 1.7 1.7 1.6 1.7 1.6 1.8 1.9 1.7 1.5 1.3 1.4 1.3 1.4 1.3 —— 54.9 1.83 2.6 1.3 109 .13 .14 BY WATER 7.94 26.3 1993 1.46 1990 1.2 1.2 1.2 1.2 1.2 1.1 1.1 1.1 1.2 1.5 1.4 1.1 1.1 1.1 1.1 .98 1.1 1.1 1.0 .91 1.1 1.4 1.0 1.0 1.2 2.3 4.5 3.4 1.8 1.7 1.6 43.89 1.42 4.5 .91 87 .10 .11 YEAR (WY) 19.5 76.1 1995 1.42 1997 1.7 1.6 1.6 1.5 1.4 1.5 1.6 1.2 1.3 1.2 1.3 1.3 1.3 1.3 1.2 .96 1.5 1.4 1.2 1.2 1.1 1.1 1.0 1.1 1.0 .98 .97 1.1 1.9 1.7 —— 39.21 1.31 1.9 .96 78 .09 .10 10.2 35.4 1992 1.23 1990 1.7 1.2 1.1 1.1 .95 .82 .76 .92 .98 1.1 1.2 1.4 1.3 1.3 1.4 1.4 1.9 2.0 2.1 3.5 1.5 .74 .63 .60 .57 .57 .64 .73 .81 .95 1.2 37.07 1.20 3.5 .57 74 .08 .10 6.69 14.4 1992 .71 1990 1.3 1.3 1.3 1.3 1.5 1.5 1.5 1.8 36 9.9 2.6 2.2 17 7.5 2.7 1.8 1.7 1.6 1.5 1.4 1.5 1.6 1.6 1.9 2.7 1.8 2.1 7.0 3.8 2.1 1.8 125.3 4.04 36 1.3 249 .28 .33 6.91 11.9 1989 2.74 1990 1.9 28 15 3.7 4.9 2.0 1.7 1.4 1.2 1.2 1.1 1.1 1.4 1.5 1.4 1.4 1.3 1.3 1.2 1.0 1.1 1.4 1.3 1.2 1.2 1.9 1.5 2.1 79 29 --- 193.4 6.45 79 1.0 384 .45 .51 32.6 94.6 1996 3.21 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS FOR 1996 CALENDAR YEAR 6940.7 19.0 2050 Sep 10 2.2 Aug 9 2.7 Aug 4 13770 1.34 18.18 29 7.4 3.3 FOR 1997 WATER YEAR WATER YEARS 1989 - 1997 2915 7 79 821 6 5780 7 21 2 1 .27 .99 .57 .64 .19 .42 .56 .64 .6 .1 Nov Jul Jul Sep Sep Jul 23 25 22 29 29 14 14.2 20.3 4.02 2050 .45 .61 15000 18.65 .42 10290 1.00 13.59 31 4.1 1.3 1996 1994 Sep 10 1996 Aug 7 1990 Jul 9 1990 Sep 10 1996 Sep 10 1996 Jul 14 1997 e Estimated RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1988 to current year. PERIOD OP DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: April 1988 to current year. INSTRUMENTATION.-- USDH-48 and automatic sediment sampler since 1988. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 10,200 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 75,700 tons (68,600 tonnes) September 10, 1996; Minimum daily mean, <0.01 ton (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,810 mg/L September 29, 1997; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 1,550 tons (1,406 tonnes) September 29, 1997; Minimum daily mean, 0.01 ton (0.01 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e!6 e!4 e21 e22 19 24 26 21 18 18 17 16 15 16 15 13 13 14 28 17 53 40 39 28 23 21 21 20 21 30 21 16 17 21 27 34 113 136 23 5 6 11 12 11 10 11 13 25 59 281 102 720 538 193 50 22 20 24 27 25 212 100 el. 2 el. 3 el. 5 el. 6 1.7 9.1 10 1.3 .22 .28 .52 .51 .44 .43 .44 .49 .88 2.4 43 4.9 252 134 22 3.8 1.4 1.2 1.4 1.5 1.4 36 5.9 18 18 17 17 17 16 16 16 33 24 41 29 21 17 16 24 54 57 44 47 69 46 79 73 39 29 25 21 20 19 27 19 20 21 23 26 22 18 345 183 518 251 136 120 106 206 941 855 1030 689 1060 581 1330 686 9 6 16 12 6 9 1.3 .89 .91 .95 1.1 1.1 .96 .77 69 12 107 21 7.6 5.6 4.5 19 323 153 125 87 461 79 520 175 1.1 .43 1.1 .72 .33 .46 TOTAL 680 542.81 962 2180.82 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) DECEMBER 19 17 17 17 16 15 14 13 13 13 17 13 12 11 11 9.9 9.0 8.6 8.5 8.0 7.6 7.3 7.0 6.8 6.8 6.6 6.8 6.8 9.3 7.8 7.0 341.8 18 33 40 44 53 64 58 48 40 33 81 77 55 42 33 26 26 28 19 12 8 6 15 19 19 11 5 8 18 36 40 —— .88 1.5 1.8 2.0 2.3 2.6 2.3 1.7 1.4 1.1 4.2 2.8 1.8 1.3 .95 .69 .63 .64 .44 .26 .17 .11 .30 .34 .35 .19 .09 .15 .45 .77 .76 34.97 e Estimated 374 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 7.0 10 8.9 11 7.0 6.3 6.6 6.5 6.3 6.4 6.8 7.1 7.3 20 12 6.8 6.2 7.1 7.1 7.1 7.2 11 12 9.1 8.6 7.2 6.3 5.7 5.5 5.2 5.2 39 54 49 80 79 75 55 38 35 37 37 36 36 141 56 10 14 22 21 19 20 21 11 5 4 4 4 8 16 24 30 .72 1.8 1.2 2.3 1.5 1.3 .95 .65 .60 .63 .67 .69 .70 11 2.7 .22 .26 .42 .39 .37 .39 .62 .37 .12 .09 .08 .07 .12 .24 .33 .42 FEBRUARY 5.6 5.3 .7 .5 .5 .3 .4 .4 .2 .1 4.0 3.8 3.8 3.7 3.5 3.6 3.3 3.3 3.4 3.3 3.0 3.3 3.1 3.0 3.0 3.1 3.1 3.0 —— 28 24 21 16 12 10 11 14 17 22 28 34 38 41 44 47 51 53 39 26 18 21 29 38 23 17 15 7 —— —— .42 .35 .26 .19 .15 .11 .13 .16 .20 .24 .30 .35 .39 .41 .45 .46 .45 .47 .35 .25 .16 .19 .24 .31 .19 .14 .12 .05 ___ —— MARCH 3.0 3.0 2.9 3.0 3.0 2.9 2.9 2.9 2.8 2.9 2.7 2.6 2.6 2.6 2.6 2.6 2.5 2.4 2.6 2.5 2.4 2.4 2.5 2.5 2.4 2.4 2.6 2.8 4.2 3.2 2.5 3 1 1 1 1 2 4 8 10 12 13 7 3 1 2 7 17 14 8 5 5 7 8 5 2 1 2 4 13 17 11 .02 .01 .01 .01 .01 .01 .03 .06 .08 .09 .09 .05 .02 .01 .02 .05 .11 .09 .05 .03 .03 .04 .05 .03 .02 .01 .01 .03 .19 .15 .08 TOTAL 246.5 31.92 106.3 7.49 84.9 1.49 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE IiAOO TOA VACA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (NG/L) (TONS/DAY) APRIL MAY JUNE 1 2.4 8 .05 1.2 8 .03 1.7 4 .02 2 2.6 11 .08 1.2 9 .03 1.6 3 .01 3 2.6 20 .14 1.2 12 .04 1.6 3 .01 4 2.3 35 .22 1.2 15 .05 1.5 3 .01 5 2.2 34 .20 1.2 13 .04 1.4 4 .01 6 2.0 27 .14 1.1 10 .03 1.5 4 .01 7 1.9 22 .12 1.1 8 .03 1.6 4 .01 8 2.0 27 .15 1.1 8 .02 1.2 3 .01 9 2.1 37 .20 1.2 8 .03 1.3 3 .01 10 2.0 48 .27 1.5 8 .03 1.2 3 .01 11 1.8 50 .24 1.4 8 .03 1.3 4 .01 12 1.8 47 .23 1.1 8 .03 1.3 4 .01 13 1.8 45 .22 1.1 8 .03 1.3 5 .02 14 1.9 47 .24 1.1 8 .03 1.3 7 .02 15 1.9 51 .26 1.1 8 .02 1.2 8 .03 16 1.7 55 .25 .98 8 .02 .96 5 .01 17 1.7 49 .22 1.1 8 .02 1.5 2 .01 18 1.7 41 .19 1.1 8 .02 1.4 1 <.01 19 1.6 34 .15 1.0 8 .02 1.2 1 <.01 20 1.7 32 .14 .91 8 .02 1.2 1 <.01 21 1.6 31 .13 1.1 8 .02 1.1 2 <.01 22 1.8 29 .14 1.4 8 .03 1.1 2 .01 23 1.9 23 .12 1.0 8 .02 1.0 3 .01 24 1.7 17 .08 1.0 8 .02 1.1 3 .01 25 1.5 13 .05 1.2 8 .03 1.0 3 .01 26 1.3 18 .06 2.3 12 .17 .98 3 .01 27 1.4 30 .11 4.5 33 1.9 .97 2 <.01 28 1.3 47 .17 3.4 19 .25 1.1 2 .01 29 1.4 32 .12 1.8 6 .03 1.9 2 .01 30 1.3 16 .05 1.7 4 .02 1.7 2 .01 31 —— —— —— 1.6 4 .02 —— —— --- TOTAL 54.9 —— 4.74 43.89 —— 3.08 39.21 —— 0.30 376 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAOO TOA VACA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 1.7 1.2 1.1 1.1 .95 .82 .76 .92 .98 1.1 1.2 1.4 1.3 1.3 1.4 1.4 1.9 2.0 2.1 3.5 1.5 .74 .63 .60 .57 .57 .64 .73 .81 .95 1.2 37.07 2915.27 JULY 2 2 3 3 3 3 5 10 20 30 40 52 29 12 5 5 6 7 8 23 5 4 5 7 7 7 7 7 7 7 7 —— .01 .01 .01 .01 .01 .01 .01 .03 .05 .09 .13 .19 .10 .04 .02 .02 .03 .04 .04 .65 .02 .01 .01 .01 .01 .01 .01 .01 .01 .02 .02 1.64 4798.04 MEAN DISCHARGE (CFS) 1.3 1.3 1.3 1.3 1.5 1.5 1.5 1.8 36 9.9 2.6 2.2 17 7.5 2.7 1.8 1.7 1.6 1.5 1.4 1.5 1.6 1.6 1.9 2.7 1.8 2.1 7.0 3.8 2.1 1.8 125.3 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 1.3 1.3 1.3 1.3 1.5 1.5 1.5 1.8 36 9.9 2.6 2.2 17 7.5 2.7 1.8 1.7 1.6 1.5 1.4 1.5 1.6 1.6 1.9 2.7 1.8 2.1 7.0 3.8 2.1 1.8 6 6 6 6 6 17 50 39 557 58 14 11 142 21 12 12 13 9 6 4 4 5 5 5 6 6 10 94 16 7 6 .02 .02 .02 .02 .03 .07 .20 .26 200 2.7 .10 .06 22 .40 .08 .06 .06 .04 .03 .02 .02 .02 .02 .03 .04 .03 .06 14 .20 .04 .03 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 1.9 28 15 3.7 4.9 2.0 1.7 1.4 1.2 1.2 1.1 1.1 1.4 1.5 1.4 1.4 1.3 1.3 1.2 1.0 1.1 1.4 1.3 1.2 1.2 1.9 1.5 2.1 79 29 5 534 103 26 59 101 90 81 72 65 56 49 42 41 40 40 43 48 53 54 55 54 47 40 33 28 23 19 1810 235 .03 163 6.3 .26 2.1 .56 .41 .31 .24 .20 .16 .15 .16 .16 .15 .15 .16 .16 .17 .15 .16 .21 .17 .13 .11 .14 .09 .11 1550 22 240.68 193.4 1748.10 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 377 DATE NOV 1996 21... 21... 21... SEP 1997 29... 29... DATE NOV 1996 21... 21... 21... SEP 1997 29... 29... TIME 1445 1455 1520 1510 1545 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 27 52 63 22 69 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 392 392 247 418 821 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 34 61 76 31 82 SEDI- MENT, SUS- PENDED (M6/L) (80154) 16400 5860 3290 36600 6328 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 46 77 90 50 93 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 17300 6200 2190 41300 14000 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 74 92 97 68 98 SED. SUSP. PALL DIAM. % FINER THAN .002 MM (70326) 12 23 28 7 30 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 95 98 99 92 99 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 15 30 37 10 41 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 100 100 98 100 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 21 40 49 15 51 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 99 100 378 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT OCT 1996 21... NOV 21... JAN 1997 06... MAR 29... AUO 09... SEP 29... TIME 1521 1450 1420 1630 1700 1600 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 594 392 6.5 3.2 224 427 SEDI- MENT, SUS- PENDED (MO/L) (80154) 112 7820 77 8 4120 6170 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 180 8300 1.4 0.10 2490 7110 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 99 72 98 53 99 94 RIO JACAGUAS BASIN 50111300 LAGO GUAYABAL AT DAMSITE NEAR JUANA DIAZ, PR 379 LOCATION.—Lat 18°05'17", long 66°30'09", Hydrologic Unit 21010004, at Damsite, 2.30 mi (3.70 km) northeast from Juana Diaz plaza, 0.70 mi (1.13 km) northeast from Escuela Salvador Bous<iuets and 2.45 mi (3.94 km) southeast from Escuela Zoilo Gracia. DRAINAGE AREA.--21.0 mi 2 (54.4 km 2 ). ELEVATION RECORDS PERIOD OP RECORD.--April 1995 to current year. GAGE.--Water stage recorder. Datum of gage is mean sea level. REMARKS.--Lago Guayabal was completed in 1913. The dam is a reinforced concrete, flatslab and buttress-type structure about 130 ft (40 m) height, a net crest lenght at the right side of the dam of 693 ft (211 m) and a crest elevation of 331 ft (101 m). It has a maximum storage capacity of 7,600 acre-feet (9.37 hm3 ) . The Guayabal Dam is owned by the Puerto Rico Electric Power Authority (P.R.E.P.A) and its primary purpose is for irrigation of lands served by the Juana Diaz Canal. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 341.55 ft (104.10 m), Sept. 10, 1996; minimum elevation, 325.99 ft (99.36 m), Sept. 29, 1997. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 341.39 ft (104.06 m), Nov. 22, 23; minimum elevation, 325.99 ft (99.36 m) , Sept. 29. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 305 321 Contents, in acre-feet 366 2,010 Elevation, in feet 330 341 Contents, in acre-feet 3,885 7,360 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 340.85 A 340.90 340.85 340.71 A 340.81 340.86 340.85 340.86 340.85 340.71 340.65 340.76 340.80 340.82 340.83 340.80 340.87 340.89 340.91 340.85 340.80 340.82 340.82 NOV 340.82 340.72 340.65 340.71 340.71 340.70 340.72 340.73 340.76 340.91 340.98 340.92 340.91 340.87 340.88 340.78 341.02 341.04 340.91 341.00 340.85 340.91 340.82 341.07 341.02 DEC 340.83 340.76 340.76 340.70 340.66 340.65 340.55 340.48 340.53 340.56 340.67 340.76 340.83 340.72 340.67 340.73 340.72 340.71 340.73 340.72 340.62 340.55 340.59 340.65 340.64 JAN 340.57 340.96 340.91 340.78 340.69 340.63 340.69 340.75 340.83 340.85 340.73 340.63 340.76 341.01 340.92 340.85 340.81 340.70 340.63 340.62 340.71 340.84 340.89 340.96 340.97 FEB 340.81 340.87 340.86 340.88 340.89 340.88 340.88 340.77 340.72 340.81 340.89 340.91 340.89 340.85 340.72 340.65 340.60 340.67 340.73 340.73 340.77 340.65 340.56 340.63 340.68 MAR 340.65 340.56 340.65 340.68 340.72 340.71 340.63 340.46 340.32 340.33 340.32 340.32 340.32 340.31 340.16 340.08 340.04 340.04 340.00 339.98 339.98 339.81 339.67 339.69 339.66 APR 339.39 339.47 339.42 339.42 339.24 339.09 339.08 339.03 338.97 338.91 338.85 338.68 338.52 338.55 338.58 338.58 338.58 338.54 338.37 338.20 338.13 338.13 337.97 337.82 337.65 MAY 337.33 337.32 337.17 337.00 337.03 337.01 336.95 336.89 336.83 336.69 336.53 336.53 336.44 336.39 336.34 336.31 336.11 335.91 335.87 335.86 335.89 335.93 335.87 335.69 335.52 JUN 335.49 335.69 335.98 A A A 336.45 336.43 336.36 336.26 336.16 336.02 335.85 335.58 335.29 335.18 335.07 334.93 A A 334.52 A A 334.20 334.04 JUL 333.09 332.93 332.77 332.54 332.30 332.06 331.97 331.85 331.72 331.57 331.38 331.12 330.86 330.79 330.67 330.54 330.42 330.39 330.27 330.57 330.82 330.95 331.06 331.15 331.15 AUG 330.48 330.13 329.81 329.58 329.31 328.79 328.55 A 328.42 328.49 328.45 328.33 328.72 329.44 329.69 329.54 329.38 329.38 329.22 329.23 329.30 329.27 329.01 328.81 328.80 SEP 328.89 329.80 329.96 329.88 329.91 330.02 330.11 330.26 330.21 330.06 329.89 329.74 329.51 329.27 329.16 328.94 328.71 328.41 328.17 327.84 327.53 327.34 327.09 326.83 326.64 26 27 28 29 30 31 MAX MIN 340.71 340.99 340.66 340.82 340.68 340.78 340.82 340.96 340.84 340.96 340.65 340.96 340.88 340.95 340.87 341.07 340.65 340.65 340.54 340.48 340.56 340.65 340.83 340.48 340.91 340.94 340.93 340.93 340.88 341.01 340.57 340.73 340.76 340.78 ___ ___ ___ 339.64 339.60 339.50 339.39 339.31 339.33 337.50 337.34 337.37 337.37 337.34 ___ 335.50 335.60 335.76 335.80 335.83 335.66 333.89 333.73 333.52 333.31 333.25 ___ 331.15 331.17 331.24 331.02 330.85 330.62 328.60 328.67 329.09 329.37 329.23 329.05 326.46 326.22 326.09 328.66 328.88 ___ 340.91 340.56 340.72 339.31 339.47 337.34 337.33 335.50 336.45 333.25 333.09 330.27 330.48 328.33 330.26 326.09 CAL YR 1996 WTR YR 1997 MAX 341.10 MAX 341.07 MIN 339.38 MIN 326.09 A No gage-height record 380 RIO JACAGUAS BASIN 50111500 RIO JACAGUAS AT JUANA DIAZ, PR LOCATION.—Lat 18°03'16", long 66°30'40", Bydrologic Unit 21010004, on Highway 14 bridge, 0.4 mi (0.6 km) wast of Juana Diaz plaza, and 4.0 mi (6.4 km) downstream from Lago Guayabal. DRAINAGE AREA.—49.8 mi 3 (129.0 km2 ). PERIOD OF RECORD.—March 1984 to current year. GAGE.—Hater-stage recorder and crest-stage gage. Elevation of gage is 131 ft (40 m), from topographic map. REMARKS.—Records poor. Flow regulation from Lago Guayabal. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB APR MAY JUN JUL AUG SEP 1 54 e!8 2 e38 e!7 3 e57 e!7 4 59 e!7 5 43 e!5 6 e27 e!5 7 25 e!5 8 38 e32 9 47 e28 10 e45 e45 11 e47 e35 12 35 e27 13 21 e21 14 19 e20 15 25 e27 16 31 e80 17 34 e84 18 33 e66 19 51 e70 20 e81 elOO 21 71 e70 22 55 e!20 23 39 ellO 24 31 e80 25 30 e54 26 28 e49 27 20 e40 28 19 e38 29 e28 e36 30 e20 e36 31 e!8 TOTAL 1169 1382 MEAN 37.7 46.1 MAX 81 120 MIN 18 15 AC-FT 2320 2740 CFSM .76 .93 IN. .87 1.03 STATISTICS OF MONTHLY MEAN MEAN 117 86.0 MAX 445 287 (WY) 1986 1988 MIN 4.31 7.57 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS e33 e33 e33 e31 e29 e27 e25 e25 e25 e32 e25 e23 e23 e23 e22 e22 e22 e21 e20 e!9 e!8 e!8 e!8 e!8 e!7 e!8 e!8 e23 e20 e!8 e!8 717 23.1 33 17 1420 .46 .54 e27 e25 e30 e!9 e!8 e!9 e!8 e!8 e!8 e!9 e20 e20 e74 e43 e26 e25 e31 e31 e31 e31 e48 e51 e39 e38 e31 e27 e25 e24 e23 e23 e24 896 28.9 74 18 1780 .58 .67 e23 e20 e!9 e!9 e!8 e!9 e!9 e!8 e!7 e!6 e!5 e!5 e!4 e!3 e!3 e!2 ell e!2 elO e9.2 elO e9.4 e9.2 e9.2 e9.4 e9.4 8.4 10___ —— 387.2 13.8 23 8.4 768 .28 .29 DATA FOR WATER YEARS 1984 34.5 151 1988 7.31 1995 FOR 24.7 144 1992 3.77 1995 8.88 16.9 1991 1.98 1994 12 8.4 8.0 7.7 7.8 e8.8 e9.1 e8.3 8.3 8.1 7.6 7.4 7.4 7.4 7.4 7.4 6.6 7.1 e7.3 e6.6 e6.6 e7.0 e7.0 e6.6 e6.6 6.2 6.2 6.1 6.2 6.4 5.7 229.3 7.40 12 5.7 455 .15 .17 - 1997 5.16 8.60 1996 1.95 1994 1996 CALENDAR YEAR 13219 36 1100 2 2 .7 .1 Sep 10 . 0 Feb 4 .2 Jan 30 5.4 6.2 eS.O e4.8 e4.3 e4.1 e4.2 e4.5 e4.2 e3.5 e3.5 e3.5 e3.7 e3.7 e3.4 e3.3 e3.3 e3.2 e3.3 e3.2 e3.5 e4.1 e3.6 e3.3 e3.0 e3.4 e3.2 e3.7 e3.4 e3.2 —— 114.7 3.82 6.2 3.0 228 .08 .09 e3.2 e3.2 e3.2 e3.2 e3.0 e3.0 e3.0 e3.2 e4.0 e3.7 e2.9 e2.9 e2.9 e2.9 e2.6 e2.9 e2.9 e2.7 e2.5 e3.0 e3.7 e2.6 e2.6 e3.2 e8.6 elO e8.8 e4.8 e4.5 e4.3 e4.5 118.5 3.82 10 2.5 235 .08 .09 e4.3 e4.3 e3.9 e3.8 e4.0 e4.3 e3.2 e3.5 e3.2 e3.5 e3.5 e3.5 e3.5 e2.7 e2.3 e3.4 e2.6 e2.2 e2.2 e2.0 e2.0 el. 6 el. 7 el. 4 el. 3 el. 3 el. 4 e2.0 el. 9 el. 9 —— 82.4 2.75 4.3 1.3 163 .06 .06 el. 4 el.l e.90 e.90 e.86 e.80 e.94 el.O el.l el. 2 el. 4 el. 3 el. 3 el. 4 el. 4 e2.0 e2.1 e2.1 e3.5 el. 5 .76 .66 .62 .60 .60 .68 .76 .86 el.O el. 2 el. 3 37.24 1.20 3.5 .60 74 .02 .03 el. 3 el. 3 el. 3 el. 3 el. 5 el. 5 el. 8 e37 e9.0 e2.7 e2.3 e!7 eS.O e3.8 1.9 1.4 1.1 1.1 .87 .83 .94 1.0 1.0 .85 .69 .82 1.1 .89 .90 .84 .68 106.71 3.44 37 .68 212 .07 .08 .51 .46 .37 .43 .43 .70 e.94 e.98 el.O .95 .81 .70 e.82 e.78 e.78 e.76 .64 .58 .56 .50 .51 .74 .81 .62 .38 .55 .82 .68 1.2 2.9 —— 22.91 .76 2.9 .37 45 .02 .02 , BY WATER YEAR (WY) 10.9 34.7 1992 1.84 1994 FOR 1997 5262 14 120 7210 65.5 215 1985 1.46 1994 38.3 198 1987 .93 1994 WATER YEAR .96 .4 .37 .51 15.29 26220 9 77 21 4 .73 .87 .2 10440 3 36 6 .29 .93 .6 .84 Nov 22 Sep 3 Aug 31 Nov 21 Nov 21 21.9 82.4 1987 1.04 1994 19.1 41.1 1985 1.59 1994 WATER YEARS 1984 40.3 80.9 6.23 4530 .24 .51 40000 29.42 29210 .81 11.00 87 8.1 2.3 Nov Jan Aug Oct Oct 40.0 164 1985 .76 1997 - 1997 1986 1994 27 1987 3 1992 31 1997 7 1985 7 1985 e Estimated A1125 CARIBBEAN SEA n 0123456 KILOMETERS I I I 1132 EXPLANATION SURFACE-WATER STATION AND NUMBER QUALJTY-QF-WATER STATION AND NUMBER WELL AND WELL NUMBER -Mop area 1125780 LAKE-ELEVATION STATION AND NUMBER 01 i r i 234 MILES Figure 23.-South coast river basins the Rfo Inabdn to Rfo Loco basins. 382 RIO INABON BASIN 50112500 RIO INABON AT REAL ABAJO, PR LOCATION.—Lat 18°05'10", long 66 033'46", Hydrologic Unit 21010004, at bridge on private road, off Highway 511 at Hacienda La Concordia, 0.4 mi (0.6 km) upstream from diversion canal, 0.5 mi (0.8 km) north of Real Aba jo, and 6.1 mi (9.8 km) northeast of Plaza Degetau in Ponce. DRAINAGE AREA.—9.70 mi 2 (25.12 km*). PERIOD OF RECORD.—1962-63 (annual low-flow measurements only), February to June 1964 (monthly measurements only)! July 1964 to July 1970, April 1971 to current year. GAGE.--Water-stage recorder. Elevation of gage is 410 ft (125 m), from topographic map. Prior to April 1971 non-recording gage and crest-stage gage at different datum. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT DEC APR MAY JUN SEP 1 43 17 2 31 15 3 32 14 4 26 13 5 23 12 6 21 13 7 21 12 8 21 12 9 21 14 10 20 12 11 21 12 12 20 16 13 19 13 14 20 11 15 22 10 16 21 11 17 20 21 18 21 e40 19 34 23 20 27 19 21 45 e86 22 33 37 23 23 e!07 24 20 103 25 17 41 26 16 29 27 15 22 28 17 19 29 16 16 30 19 15 31 19 —— TOTAL 724 785 MEAN 23.4 26.2 MAX 45 107 MIN 15 10 AC-FT 1440 1560 CFSM 2.41 2.70 IN. 2.78 3.01 13 12 11 11 9.7 8.9 8.9 8.7 8.6 8.6 12 9.3 8.5 8.8 10 9.5 9.2 8.9 8.8 9.7 11 10 8.9 8.5 8.9 10 12 12 12 11 10 309.4 9.98 13 8.5 614 1.03 1.19 9.4 28 16 11 9.3 9.7 8.9 22 14 9.9 8.8 8.4 16 16 14 9.0 7.6 8.2 9.1 10 12 14 10 8.1 7.8 7.6 7.7 7.6 7.5 7.3 7.0 341.9 11.0 28 7.0 678 1.14 1.31 8.0 15 11 7.5 7.1 6.8 6.2 6.1 6.1 6.6 6.5 6.3 5.7 4.9 4.8 4.5 4.6 4.6 5.2 4.5 5.0 5.0 4.2 4.2 4.3 4.6 4.5 4.5 —— 168.3 6.01 15 4.2 334 .62 .65 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1964 MEAN 45.2 33.2 MAX 148 77.9 (WY) 1986 1978 MIN 14.5 8.32 (WY) 1994 1977 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 12.2 26.5 1966 4.43 1977 FOR 8.60 45.5 1992 4.11 1989 5.75 13.1 1996 3.05 1977 .7 .7 .2 .9 .6 .9 .8 .4 .3 .1 .0 .2 .2 e .1 e4.0 e3.9 e3.8 e4.0 e8.8 eS.O e3.7 e3.3 e3.2 e3.1 e3.0 e3.4 e7.0 e6.0 eS.O e4.0 e3.5 137.8 4.45 8.8 3.0 273 .46 .53 - 1997 5.73 16.4 1972 1.85 1977 1996 CALENDAR YEAR 7499.9 20.5 754 4.1 4.4 14880 2.11 28.76 34 11 6.2 Sep 10 Feb 4 Jan 31 4.2 4.4 3.7 3.4 3.1 2.7 2.9 2.8 2.8 2.7 2.8 2.7 2.6 2.8 2.8 2.7 2.6 2.7 2.7 2.7 3.0 2.5 2.3 2.5 2.9 2.7 2.6 2.2 2.1 2.3 —— 84.9 2.83 4.4 2.1 168 .29 .33 2.7 2.8 7.2 5.9 2.9 e2.9 e3.0 e3.0 2.4 7.0 2.9 2.5 2.3 2.4 2.0 1.9 2.0 1.9 2.0 2.0 2.6 2.2 1.9 1.8 1.7 4.8 26 16 5.3 4.0 3.6 131.6 4.25 26 1.7 261 .44 .50 3.4 3.4 3.3 3.3 3.4 3.4 2.9 2.9 3.4 3.5 3.4 3.3 3.1 3.0 2.7 2.7 2.9 2.8 4.6 6.3 3.6 3.1 3.5 3.2 2.2 2.2 2.6 3.0 2.9 3.6 ___ 97.6 3.25 6.3 2.2 194 .34 .37 2.3 2.6 2.8 3.3 4.0 3.5 3.7 6.0 5.8 3.9 e4.2 e4.7 e4.9 3.8 3.2 3.0 2.8 3.9 5.3 8.6 11 6.7 4.6 3.8 3.4 3.4 3.6 3.5 3.3 3.3 3.5 132.4 4.27 11 2.3 263 .44 .51 3.5 3.4 7.7 7.8 3.7 3.0 2.8 el9 e!5 e!3 e7.8 e8.8 e!3 e38 e25 e23 15 15 12 11 8.7 7.9 10 ell 7.7 5.2 5.8 e38 e!7 e!3 7.4 379.2 12.2 38 2.8 752 1.26 1.45 6.8 e!8 e!4 11 5.6 4.8 4.1 3.6 3.1 2.8 3.0 4.5 5.9 4.3 5.1 4.0 3.3 2.9 2.6 2.2 2.6 3.5 3.5 e4.3 e3.0 3.6 2.7 4.9 e29 e!6—— 184.7 6.16 29 2.2 366 .63 .71 , BY WATER YEAR (WY) 8.06 19.2 1992 2.76 1975 FOR 1997 3476 9 107 1 2 1270 12 6900 13 20 5 2 19.2 76.7 1969 1.94 1967 WATER YEAR .8 .53 Nov 23 .7 May 25 .0 May 14 Nov 23 .55 Nov 23 .98 .33 .6 .7 15.7 49.8 1969 2.75 1967 11.7 32.7 1979 1.77 1990 WATER 17 30 7 2500 1 19000 25 12890 1 24 39 8 3 16.9 46.1 1979 4.47 1974 YEARS 1964 .8 .9 .44 Sep .80 Jul .1 Mar Oct .30 Oct .83 .92 .9 .2 32.9 119 1975 6.16 1997 - 1997 1969 1994 16 1975 23 1977 31 1977 7 1985 7 1985 e Estimated RIO BUCANA BASIN 50113800 RIO CERRILLOS ABOVE LAGO CERRILLOS NEAR PONCE, PR 383 LOCATION.--Lat 18°07'01", long 66°36'17", Hydrologic Unit 21010004, on right bank, 0.3 mi (0.5 km) downstream from confluence with Rio San Patricio, 0.1 mi (0.2 km) southwest of Hwy 139 and 2.4 mi (3.7 km) northwest of Mayaguez. DRAINAGE AREA.-- 15.4 mi 2 (39.9 km2 ). PERIOD OF RECORD.--December 1988 to current year. GAGE.--Water-stage recorder and crest-stage gage. Elevation of gage is 720 ft (210 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DXSCBAR6E DAY OCT NOV 1 85 28 2 67 25 3 72 24 4 56 23 5 47 22 6 40 27 7 36 24 8 33 23 9 32 34 10 31 31 11 29 28 12 30 42 13 29 32 14 28 24 15 36 22 16 29 22 17 26 77 18 27 84 19 44 56 20 55 47 21 80 162 22 62 90 23 41 241 24 34 141 25 31 74 26 29 57 27 29 47 28 36 42 29 31 38 30 28 36 31 34 TOTAL 1267 1623 MEAN 40.9 54.1 MAX 85 241 MIN 26 22 AC-FT 2510 3220 CFSM 3.43 4.55 IN. 3.96 5.07 STATISTICS OF MONTHLY MEAN MEAN 65.5 33.5 MAX 154 59.3 (WY) 1991 1993 MIN 24.6 9.77 (WY) 1992 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS :, CUB DEC 33 31 29 28 27 26 26 25 24 24 30 23 22 21 21 20 19 18 17 17 17 16 16 15 15 15 15 16 15 14 14 649 20.9 33 14 1290 1.76 2.03 1C FEET PER JAN 13 35 24 19 17 16 14 15 16 15 14 13 19 18 15 14 13 13 13 15 26 23 17 15 14 13 13 13 12 11 11 499 16.1 35 11 990 1.35 1.56 SECOND, V DAILY FEB 12 16 12 11 11 11 10 10 10 10 11 11 9.6 9.2 9.2 8.9 8.7 8.7 8.8 8.6 8.5 8.1 7.9 7.7 7.8 7.7 7.7 7.4 ___ ___ —— 269.5 9.63 16 7.4 535 .81 .84 DATA FOR WATER YEARS 1989 15.7 26.2 1993 8.10 1995 FOR 16.7 59.0 1992 6.59 1995 12.2 26.1 1996 6.34 1990 1996 CALENDAR YEAR 13792.8 37.7 1580 6.6 6.9 27360 3.17 43.12 73 22 8.7 Sep 10 May 8 May 6 «ATEK YEAR OCTOBER 1995 TO SEFTEHBER 1997 MEAN VALUES MAR 7.2 7.2 7.2 7.3 7.1 7.0 6.9 6.9 6.8 6.8 6.5 6.3 6.3 6.2 6.3 6.4 6.2 6.7 10 6.2 5.9 5.7 5.5 5.5 5.6 5.5 9.9 9.2 8.3 7.7 6.4 212.7 6.86 10 5.5 422 .58 .66 APR 6.6 7.0 8.2 6.6 6.2 5.9 5.7 5.9 5.5 4.8 4.9 4.8 .7 .7 .6 .6 .5 .5 .4 .4 .4 .6 .5 .3 .1 .1 .0 .0 3.9 3.9 —— 150.3 5.01 8.2 3.9 298 .42 .47 MAY 3.9 3.9 7.8 5.0 4.1 5.9 5.4 4.3 8.2 8.4 5.6 .9 .6 .6 .2 .3 .5 4.1 3.9 3.9 4.2 4.0 3.9 4.0 3.9 4.1 12 10 4.9 4.3 4.1 160.9 5.19 12 3.9 319 .44 .50 JUN .1 .1 .0 .0 .0 4.0 3.8 3.7 3.6 3.6 3.5 3.5 3.4 3.4 3.3 3.2 3.2 3.5 12 6.3 4.2 4.1 4.8 4.5 3.7 3.5 3.8 4.0 3.6 3.7 —— 124.1 4.14 12 3.2 246 .35 .39 JUL 3.5 3.4 3.3 3.3 3.2 3.1 3.4 23 8.9 4.9 4.2 19 8.9 5.2 4.6 4.5 4.4 5.0 5.3 11 15 10 6.4 5.2 4.7 .4 .3 .3 .2 .0 4.1 198.7 6.41 23 3.1 394 .54 .62 AUG 4.3 4.1 24 11 6.1 5.4 5.1 7.4 21 20 14 15 e23 e34 e31 e!3 e9.7 e8.2 e7.3 6.9 7.6 24 18 19 13 8.7 10 22 19 14 10 435.8 14.1 34 4.1 864 1.18 1.36 SEP 43 60 37 16 11 9.7 8.4 7.6 7.1 6.7 6.4 11 8.7 6.7 6.6 6.3 6.4 6.0 5.8 5.4 5.7 7.7 6.8 30 13 9.8 7.7 8.7 16 12 393.2 13.1 60 5.4 780 1.10 1.23 - 1997, BY WATER YEAR (WY) 11.1 27.5 1989 4.77 1990 FOR 13.7 24.3 1989 5.01 1997 1997 5983 16 241 3 3 2120 5 3 11870 1 18 34 8 4 24.0 68.2 1993 4.58 1990 WATER YEAR .2 .4 Nov 23 .1 Jul 6 .3 Jul 1 Nov 23 .72 Nov 23 .0 Jul 6 .38 .70 .9 .0 22.6 46.4 1996 4.14 1997 14.6 26.7 1991 3.37 1994 WATER 25 35 9 1580 3 3 10600 10 18580 2 29 56 13 4 28.2 53.1 1991 11.3 1994 YEARS 1989 .7 .7 .94 Sep .0 Jul .2 Jul Sep .62 Sep .16 .29 .7 55.2 126 1996 13.1 1997 - 1997 1993 1994 10 1996 6 1994 27 1994 10 1996 10 1996 e Estimated 384 RIO BUCANA BASIN 50113950 LAGO CERRILLOS AT DAMSITE NEAR PONCE, PR LOCATION.--Lat 18°04'41", long 66°34'38", Hydrologic Unit 21010004, on left bank west from intake house of dam, 0.7 mi (1.1 km) southwest from Iglesia San Hateo at Real Abajo, 3.2 mi (5.1 km) northeast from Hospital de Distrito de Ponce, and 2.2 mi (3.5 km) northwest from Escuela YUca. DRAINAGE AREA.--17.4 mi' (45.1 km 2 ). ELEVATION RECORDS PERIOD OP RECORD.--October 1992 to current year . REVISED RECORDS.--WDR PR-94-1: 1993,1994. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.--Lake is formed by Cerrillos Dam, a rockfilled ungated structure completed in 1992. Elevation of crest is 611 ft (186 m) above mean sea level, with a structural height of 323 ft (98 m) and a lenght of 1,555 ft (474 m) . The dam has a capacity of approximately 47,900 ac-ft (59.1 hm3 ). The dam is operated by U.S. Army Corps of Engineers and its purpose is for flood control, water supply, power generation, and recreation. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 580.83 ft (177.04 m), Nov. 24, 1996; Minimum elevation, 416.63 ft (126.99 m), Oct. 1, 1992, (Revised). EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 580.83 ft (177.04 m), Nov. 24; minimum elevation, 558.76 ft (170.31 m), Sept. 29. Capacity Table Elevation , in feet 328 426 492 (based on data from U.S. Army Corps of Engineers) Contents in acre-feet Elevation, in feet 0 3,206 10,621 525 558 590 Contents in acre-feet 16,990 25,786 37,509 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 MAX MIN OCT 574.37 A 573.47 573.40 573.29 573.15 572.99 572.80 572.67 572.63 572.55 572.62 572.67 572.59 573.20 573.30 573.39 573.39 573.36 573.34 573.29 572.35 571.63 571.77 571.87 27 572.08 28 572.22 29 572.33 30 572.44 31 572.56 574.37 571.63 NOV 572.66 572.75 572.83 572.89 572.95 573.05 573.11 573.23 573.37 573.46 573.59 573.86 574.01 574.10 574.16 574.22 574.81 575.24 575.48 575.81 577.66 578.00 580.39 580.05 578.60 DEC 577.78 577.78 577.91 578.02 578.11 578.11 578.08 577.98 577.91 577.95 578.06 578.13 578.20 578.28 578.37 578.36 578.28 578.17 578.08 577.98 577.98 578.04 578.07 578.11 578.17 578.34 578.23 578.09 577.95 580.39 572.66 578.26 578.32 578.39 578.33 578.24 578.39 577.78 JAN 578.10 578.26 578.21 578.16 578.06 577.96 577.96 578.07 578.11 578.17 578.21 578.24 578.30 578.37 578.41 578.45 578.38 578.25 578.11 578.07 578.17 578.28 578.33 578.37 578.38 572.00 578.42 578.20 578.43 578.35 578.22 578.07 578.05 578.06 578.45 577.96 FEB 578.11 578.22 578.26 578.29 578.30 578.32 578.33 578.33 578.35 578.36 578.38 578.40 578.41 578.42 578.42 578.43 578.43 578.43 578.43 578.43 578.43 578.44 578.44 578.44 578.44 578.45 578.11 MAR 578.44 578.44 578.44 578.46 578.45 578.45 578.44 578.43 578.42 578.41 578.35 578.32 578.33 578.33 578.33 578.33 578.33 578.38 578.42 578.41 575.95 575.85 575.85 575.85 575.89 APR 576.02 576.03 576.04 576.04 576.04 576.01 575.99 576.00 575.98 575.98 575.98 575.96 575.94 575.93 575.92 575.90 575.89 575.88 575.87 575.86 575.85 575.84 575.82 575.81 575.78 MAY 575.68 575.66 575.70 575.68 575.67 575.68 575.66 575.64 575.65 575.69 575.69 575.68 575.67 575.68 575.66 575.63 575.63 575.61 575.55 575.53 575.56 575.51 575.51 575.50 575.49 JUN 575.66 575.65 575.65 575.64 575.48 575.36 575.13 574.95 574.81 574.65 574.50 574.33 574.15 574.00 573.85 573.65 573.52 573.36 573.25 573.11 572.96 572.82 572.69 572.53 572.38 JUL 571.48 571.32 571.16 571.01 570.84 570.67 570.50 570.46 570.36 570.21 570.09 570.01 569.89 569.76 569.61 569.56 569.39 569.24 569.10 569.06 569.00 568.90 568.73 568.55 568.33 AUG 566.99 566.73 566.78 566.65 566.46 566.25 566.12 565.96 565.85 565.81 565.67 565.54 565.44 565.67 565.67 565.50 565.26 565.00 A 564.72 564.52 564.35 564.19 564.10 563.95 578.46 575.83 576.04 575.69 575.70 575.49 575.66 571.63 571.48 567.12 566.99 562.93 SEP A 563.29 563.24 563.12 562.96 562.79 562.61 562.43 562.24 562.05 561.85 561.69 561.51 561.31 561.11 560.89 560.69 560.48 560.29 560.06 559.83 559.67 559.47 559.43 559.25 578.45 578.45 578.45 ___ ___ ___ 575.83 575.90 575.93 575.95 576.01 576.01 575.76 575.74 575.72 575.69 575.70 ___ 575.52 575.63 575.69 575.69 575.68 575.67 572.22 572.04 571.90 571.73 571.63 ___ 568.12 567.95 567.76 567.56 567.34 567.12 563.75 563.60 563.50 563.41 563.26 562.93 559.06 558.87 558.84 558.98 558.88 563.29 558.84 CAL YR 1996 WTR YR 1997 MAX 580.39 MAX 580.39 MIN 541.26 MIN 558.84 A No gage-height record RIO BUCANA BASIN 50114000 RIO CERRILLOS NEAR PONCE, PR 385 LOCATION. "Lat 18°04'15", long 66°34'51", Hydrologic Unit 21010004, on right bank off Highway 139, 0.8 mi (1.3 km) below Lago Cerrillos Dam, 2.3 mi (3.7 km) upstream from Quebrada Ausubo and 4.6 mi (7.4 km) northeast of Plaza Degetau in Ponce. DRAINAGE AREA.—17.8 mi' (46.1 km»), excludes 17.4 mi* (45.1 km2 ) upstream from Lago Cerrillos Dam. WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February to April 1964 (monthly measurements only). May 1964 to June 1985, July 1985 to April 1991 (semi-monthly measurements only). May 1991 to current year. GAGE.—Water-stage recorder. Datum of gage is 253.10 ft (77.145 m), above mean sea level. March 22, 1977 at site 0.15 mi (0.24 km) upstream and datum 9.90 ft (3.018 m) higher. Prior to REMARKS.—Records poor. Flow regulated by Lago Cerrillos Dam since May 1991. Gage-height and precipitation satellite telemetry at station. Prior to June 1985 some low-flow regulation by construction upstrream. Maximum discharge prior to regulation, 22,400 ftVs (6.34 mVs), Sept. 16, 1975, gage-height, 11.2 ft (3.414 m), site and datum then in use from floodmarks, from rating curve extended above 150 ftVs (4.25 mVs), on basis of slope-area measurements of peak flow; minimum discharge prior to regulation, 2.2 ftVs ( 0.062 mVs), May 28, 1967. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEW DAILY MEAN VALUES DAY OCT NOV DEC JAN MAR APR MAY JUN 1997 JUL AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN MAX MIN AC-FT CFSM IN. 145 239 131 80 80 80 80 93 69 35 18 5.1 5.2 5.1 5.0 17 25 38 80 80 185 291 185 6.0 5.3 5.3 5.3 5.5 8.7 12 13 2032.5 65.6 291 5.0 4030 3.68 4.25 STATISTICS OF MEAN MAX (WY) MIN (WY) 70.8 202 1971 4.93 1996 13 13 9.8 5.0 4.8 5.0 5.3 6.3 5.4 5.3 5.7 6.2 5.5 5.3 5.3 5.6 5.5 5.5 6.0 6.0 5.9 65 197 319 354 114 76 74 74 74—— 1482.4 49.4 354 4.8 2940 2.78 3.10 74 28 4.5 4.6 4.7 23 40 41 41 16 .3 .1 .1 .1 .0 23 37 37 37 37 15 3.9 3.9 3.8 3.8 3.8 3.8 3.7 3.7 21 43 577.8 18.6 74 3.7 1150 1.05 1.21 MONTHLY MEAN DATA 54.3 124 1978 5.21 1996 21.8 49.1 1966 4.81 1995 43 43 43 43 43 43 18 4.9 4.9 5.0 5.2 5.0 5.1 5.0 5.1 5.1 30 43 43 28 5.1 4.9 4.7 4.7 4.7 4.7 27 48 51 22 5.7 647.8 20.9 51 4.7 1280 1.17 1.35 FOR WATER 14.9 74.2 1992 4.52 1993 5.6 5.7 5.7 5.7 5.7 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.6 5.7 5.7 5.7 5.7 5.7 5.7 5.7 5.7 —— 156.6 5.59 5.7 5.5 311 .31 .33 YEARS 1964 9.64 20.0 1969 4.37 1993 5.6 5.5 5.5 6.3 5.5 5.6 5.5 5.5 5.5 5.5 5.5 5.5 5.5 7.0 5.7 5.8 5.7 6.3 5.7 5.5 329 40 8.5 7.9 7.6 7.6 7.7 8.0 7.8 8.2 7.7 554.2 17.9 329 5.5 1100 1.00 1.16 - 1997, 10.1 20.3 1969 5.07 1995 7.2 7.1 6.9 6.7 6.3 6.1 5.9 5.6 5.6 5.7 5.9 5.8 5.6 5.8 6.0 6.0 5.9 6.0 6.0 6.1 6.1 6.1 6.0 6.4 6.5 6.7 7.1 7.4 6.9 6.7 —— 188.1 6.27 7.4 5.6 373 .35 .39 BY WATER 15.4 106 1985 4.93 1979 6.7 5.4 6.6 5.2 6.9 4.9 7.2 6.1 7.2 4.9 7.2 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.4 7.3 7.4 7.3 7.3 7.4 7.5 8.6 7.3 7.1 7.0 6.7 6.6 6.3 6.0 5.8 .9 .9 .9 .8 .8 .8 .8 .7 .8 .7 .7 .7 .8 .9 .9 .9 .8 .9 .9 .9 .9 .9 .9 .9 .9 5.7 220.5 147.5 7.11 4.92 8.6 6.1 5.7 4.7 437 293 .40 .28 .46 .31 YEAR (WY) 37.3 26.3 221 88.9 1985 1969 4.14 3.69 1967 1995 4.9 6.3 5.0 5.1 5.1 5.2 5.1 5.2 5.2 5.2 5.6 5.3 5.4 5.5 5.6 5.9 5.9 5.9 5.8 6.1 6.1 6.0 5.9 5.9 5.9 5.9 6.0 6.0 6.0 6.1 8.0 177.1 5.71 8.0 4.9 351 .32 .37 23.5 71.1 1968 4.75 1995 5.9 5.5 8.8 5.7 5.3 5.3 5.1 4.8 4.8 6.4 5.0 4.6 4.6 4.7 4.6 4.7 5.0 5.1 5.1 5.1 5.1 5.2 5.3 5.3 5.3 5.3 5.6 5.7 5.7 5.7 5.7 166.0 5.35 8.8 4.6 329 .30 .35 31.6 82.4 1968 5.26 1995 5.9 5.9 5.9 8.1 5.8 5.5 5.2 .7 .5 .1 .9 .1 .0 3.9 4.0 3.8 3.9 3.9 3.9 3.9 3.9 3.9 3.9 3.9 4.0 .0 .1 .1 .5 .3 —— 135.5 4.52 8.1 3.8 269 .25 .28 59.7 256 1975 4.52 1997 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS FOR 1996 CALENDAR YEAR 8518.8 23.3 536 Sep 11 3.5 Jul 27 3.8 Dec 23 16900 1.31 17.80 64 5.7 4.4 FOR 1997 WATER YEAR WATER YEARS 1964 - 1997 6486.0 17.8 354 3.7 3.8 1250 7.55 12860 1.00 13.56 42 5.7 4.6 NOV 25 Dec 28 Dec 23 Mar 21 Mar 21 30.7 53.9 5.35 11500 .64 1.7 1320 7.74 22270 1.73 23.47 73 14 5.0 1969 1995 Oct 7 1985 Aug 19 1992 Aug 24 1992 Sep 10 1996 Sep 10 1996 386 RIO BUCANA BASIN 50114000 RIO CERRILLOS NEAR PONCE, PR--Continued WATER-QUALITY RECORDS Location.--Lat 18°04'15", long 66°34'51", Hydrologic unit 21010004, on right bank off Highway 139, 2.3 mi (3.7 km) upstream from Quebrada Ausubo and 4.6 mi (7.4 km) northeast of Plaza Degetau in Ponce. DRAINAGE AREA.—17.8 mi* (46.1 km2 ) PERIOD OF RECORD.—Water years 1964 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 16 FEB 28 JUN 03 SEP 03 DATE 1996 1997 . . . ... DATE OCT 1996 16... FEB 1997 28... JUN 03... SEP 03... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0945 1015 1040 0940 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 150 -- 130 140 FLUO- RIDE, DIS- 5.0 6.6 5.7 5.8 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 51 — 42 46 SILICA, DIS- SOLVED SOLVED (MG/L DATE OCT 1996 16... FEB 1997 28... JUN 03... SEP 03... (MG/L AS F) (00950) 0.30 -- 0.26 0.22 AS SIO2) (00955) 25 — 24 24 372 321 324 347 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.8 — 6.0 5.2 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 236 — 200 227 8.0 26.0 0 7.2 24 . 0 0 7.2 26.0 0 7.2 25.5 0 SODIUM SODIUM, AD- DIS- SORP- SOLVED TION (MG/L RATIO AS NA) (00930) (00931) 17 0.6 __ 15 0.6 15 0.5 RESIDUE SOLIDS, TOTAL DIS- AT 105 SOLVED DEG. C, (TONS SUS- PER PENDED DAY) (MG/L) (70302) (00530) 3.19 1 5 3.08 4 3.53 2 .50 .70 .47 .45 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.0 — 1.1 0.73 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.200 0.060 0.030 0.040 8.5 8.6 7.7 8.2 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 150 140 150 170 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 <0.010 103 100 95 101 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.210 0.070 0.030 0.040 <10 <10 <10 <10 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 39 -- 24 26 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.010 0.020 0.020 K90 K10 K64 350 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 7.4 — 7.5 7.8 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 <0.20 <0.20 310 70 K73 330 DATE OCT 1996 16... FEB 1997 28... JUN 03... SEP 03... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.02 <0.20 <0.20 <0.20 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.24 <0.20 <0.20 <0.20 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 1.1 0.45 0.48 0.84 PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 0.050 <0.020 0.220 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- <10 — non-ideal count RIO BOCANA BASIN 50114000 RIO CERRILLOS NEAR PONCE, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 387 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (OO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (OO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (DG/L AS EG) (71900) SELE- NIUM, TOTAL (OO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (OO/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (DO/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (DG/L) (32730) METHY- LENE BLUE ACTIVE SOB- STANCE (MG/L) (38260) OCT 1996 16... FEB 1997 28... JON 03... SEP 03... 80 50 <1 <1 40 18 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 388 RIO BUCANA BASIN 50114390 RIO BUCANA AT HWY 14 BRIDGE NEAR PONCE, PR LOCATION.—Lat 18°02'29", long 66°34'58", Hydrologic Unit 21010004, on left bank, 200 ft (61 m) upstream from bridge on Highway 14 and 4.0 mi (6.4 km) downstream from Lago Cerrillos Dam, 2.8 mi (4.5 km) northeast of Degetau Plaza in Ponce. DRAINAGE AREA.--24.9 mi 2 (64.5 km2 ). PERIOD OF RECORD.—October 1985 to September 1986 (maximum only), published as "Rio Bucana Floodway Channel at Highway 14 bridge", October 1986 to July 1987 (maximum only), August 1987 to current year. GAGE.--Water-stage recorder and crest-stage gage. Datum of gage is 116.40 ft (35.500 m) above mean sea level. Prior to Oct. 1, 1986, crest-stage gage located at Highway 14 bridge, at elevation of mean sea level. REMARKS.--Records poor. Flow regulated by Lago Cerrillos Dam 0.4 mi upstream. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEE MAR APR AUG SEP 1 78 7.4 2 314 7.2 3 155 6.9 4 73 7.0 5 70 6.8 6 66 6.9 7 63 7.5 8 62 8.4 9 76 11 10 32 8.9 11 24 8.9 12 9.0 20 13 8.0 12 14 7.5 5.4 15 7.3 4.6 16 7.2 4.6 17 6.8 5.6 18 9.9 6.1 19 61 5.0 20 61 7.5 21 148 14 22 433 25 23 447 392 24 24 608 25 9.6 750 26 9.0 159 27 8.7 90 28 8.7 80 29 8.2 76 30 7.6 69 31 7.5 TOTAL 2302.0 2420.7 MEAN 74.3 80.7 MAX 447 750 MIN 6.8 4.6 AC-FT 4570 4800 CFSM 2.98 3.24 IN. 3.44 3.62 71 54 15 14 13 21 41 42 42 30 11 11 10 13 13 22 44 45 42 42 30 10 9.3 8.5 8.7 8.4 8.1 7.9 7.9 15 38 747.8 24.1 71 7.9 1480 .97 1.12 STATISTICS OF MONTHLY MEAN DATA MEAN 122 61.0 MAX 527 222 (WY) 1991 1988 MIN 6.34 5.09 (WY) 1996 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 17.0 49.1 1988 5.03 1996 FOR 38 39 41 41 41 41 28 8.1 7.6 7.0 8.2 7.6 7.3 7.3 7.2 7.0 18 34 35 31 7.8 7.7 6.9 6.6 6.6 6.6 15 36 36 25 6.9 615.4 19.9 41 6.6 1220 .80 .92 6.5 6.3 6.3 6.0 5.8 5.7 5.9 6.0 6.1 6.1 6.1 6.5 6.8 6.8 6.6 6.3 6.3 6.2 6.1 6.0 6.5 6.7 6.8 6.9 6.8 6.6 6.6 6.6 ___ ___ ___ 177.9 6.35 6.9 5.7 353 .26 .27 FOR WATER YEARS 1987 43.9 337 1992 4.51 1994 10.1 19.3 1995 4.10 1994 6.7 6.6 6.6 7.5 7.1 6.6 6.6 6.6 6.8 7.2 7.0 7.1 7.0 7.6 7.2 6.6 6.6 7.1 7.6 6.8 664 60 8.8 5.4 4.8 4.4 5.2 7.2 6.4 5.9 6.5 917.5 29.6 664 4.4 1820 1.19 1.37 - 1997 14.4 48.0 1989 4.49 1994 1996 CALENDAR YEAR 12696 34 1430 2 3 25180 1 18 53 7 4 .8 .7 Sep 11 .8 Jul 27 .4 Jul 21 .39 .97 .1 .5 5.6 7.2 6.6 6.0 5.6 5.6 5.6 5.6 5.6 5.4 5.4 5.4 5.3 5.0 5.1 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.0 5.0 5.0 5.0 5.0 5.0 5.0 161.6 5.39 7.2 5.0 321 .22 .24 5.0 4.9 5.0 .9 .7 .6 .6 .6 .6 .6 .6 .6 .4 .4 .4 .2 .4 .3 .4 .4 4.4 5.1 5.7 5.2 5.1 5.2 5.2 5.6 5.1 5.1 5.0 148.3 4.78 5.7 4.2 294 .19 .22 5.2 5.0 5.0 5.1 9.4 5.3 5.2 5.2 5.3 5.4 5.4 5.4 5.2 5.2 5.2 4.9 5.0 5.1 5.3 5.3 5.3 5.2 5.0 5.0 5.0 5.1 5.3 4.8 4.7 5.0 158.5 5.28 9.4 4.7 314 .21 .24 5.5 6.5 5.7 5.1 5.0 5.2 5.8 4.8 4.6 4.7 4.8 5.2 4.7 4.8 4.7 5.6 5.4 5.2 5.4 7.9 8.8 9.2 7.9 7.9 7.5 6.8 6.7 6.2 5.8 6.0 6.6 186.0 6.00 9.2 4.6 369 .24 .28 5.5 4.9 33 9.8 6.7 6.3 6.1 5.9 5.6 21 11 8.0 7.9 12 9.6 8.0 8.3 8.4 7.8 7.6 7.6 7.8 7.7 7.5 7.6 7.2 7.0 6.8 6.8 6.5 6.3 272.2 8.78 33 4.9 540 .35 .41 6.7 7.3 6.7 7.6 7.3 6.6 6.0 5.8 5.8 5.5 5.2 5.0 5.0 4.9 5.1 5.0 4.6 4.6 4.7 4.4 4.4 5.9 5.9 5.2 5.3 6.6 5.9 5.3 5.5 6.1 --- 169.9 5.66 7.6 4.4 337 .23 .25 , BY WATER YEAR (WY) 13.9 42.5 1992 4.74 1994 FOR 1997 8277 22 750 4 4 3170 12 16420 12 41 6 4 24.2 94.9 1992 4.29 1994 WATER YEAR .8 .7 Nov 25 .2 May 16 .4 May 13 Mar 21 .68 Mar 21 .91 .37 .6 .9 23.8 80.5 1989 4.90 1994 17.5 51.4 1991 4.37 1994 WATER 39 78 7 4340 2 2 17400 13 28420 1 21 68 9 4 40.8 169 1988 4.06 1994 YEARS 1987 .2 .0 .43 Jan .5 Sep .8 Sep Oct .48 Oct .58 .41 .0 .6 73.7 265 1989 5.66 1997 - 1997 1991 1994 6 1992 28 1992 23 1992 7 1995 7 1995 RIO PORTUGUES BASIN 50115000 RIO PORTUGUES NEAR PONCE, PR 389 LOCATION.--Lat 18°04'45", long 66°38'01", Hydrologic Unit 21010004, on right bank 30 ft (9 m) upstream from bridge on Highway 504, 0.2 mi (0.3 km) upstream from small unnamed tributary, 4.4 mi (7.1 km) upstream from Rio Chiquito, and 4.7 mi (7.6 km) north of Plaza Degetau in Ponce. DRAINAGE AREA.--8.82 mi' (22.84 km'). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February to June 1964 (monthly measurements only), July 1964 to current year. GAGE.—Hater-stage recorder. Elevation of gage is 470 ft (143 m), from topographic map. Prior to Dec. 4, 1964, non-recording gage at same site and datum. REMARKS.—Records poor. Some low-flow regulation due to unknown activity upstream. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR MAY JON JDL AUG SEP 1 e26 8.1 2 e21 7.4 3 e!8 7.2 4 e!6 7.0 5 el? 6.7 6 el? 7.2 7 e!8 7.7 8 e!5 e? . 1 9 e!4 ell 10 e!4 13 11 e!3 9.6 12 e!3 e53 13 e!3 41 14 e!3 20 15 e!4 17 16 e!3 13 17 12 46 18 12 33 19 10 15 20 17 12 21 24 67 22 21 13 23 15 180 24 10 110 25 9.3 31 26 8.3 21 27 7.9 17 28 8.0 16 29 8.3 15 30 7.9 15 31 8.5 TOTAL 434.2 827.0 MEAN 14.0 27.6 MAX 26 180 MIN 7.9 6.7 AC -FT 861 1640 CFSM 1.59 3.13 IN. 1.83 3.49 14 14 13 13 13 13 13 13 12 12 14 12 12 12 12 12 11 11 10 9.4 9.4 9.9 8.4 10 10 10 11 11 8.8 7.6 8.2 349.7 11.3 14 7.6 694 1.28 1.47 STATISTICS OF MONTHLY MEAN DATA MEAN 45.0 31.3 MAX 120 80.1 (WY) 1986 1988 MIN 11.9 5.82 (WY) 1992 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-PT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 12.0 27.3 1988 2.71 1992 FOR e!2 e26 e!4 elO e!5 elO e9.0 elO e8.0 e8.5 e9.2 elO elO e8.0 e7.6 e6.7 e6.4 e6.2 e6.2 e6.8 e9.2 e9.4 e7.6 e6.8 e6.6 e6.5 e6.4 e6.5 e6.2 e6.4 e6.4 277.6 8.95 26 6.2 551 1.02 1.17 e6.3 e8.6 e7.6 e6.6 e6.6 e6.4 e5.8 e5.2 e5.2 e5.0 e4.6 e4.7 e4.5 e4.6 e4.7 e4.7 e4.7 e4.6 e4.6 e5.0 e4.9 e4.8 e4.7 e4.6 e4.5 e4.6 e4.7 e4.6 —— —— 147.4 5.26 8.6 4.5 292 .60 .62 FOR HATER YEARS 1964 8.74 45.5 1992 3.65 1989 6.48 14.6 1996 2.62 1989 e4.0 e3.9 e4.1 e4.2 e4.3 e4.0 e4.0 e3.9 e3.9 e3.7 e3.6 e3.8 e4.1 e4.1 e4.7 e4.4 e4.5 eS.O 8.8 e5.9 e4.0 e3.7 e3.5 e3.5 e3.6 e3.5 4.6 eS.O e3.8 e3.2 e3.0 130.3 4.20 8.8 3.0 258 .48 .55 - 1997 5.67 13.4 1976 2.08 1977 1996 CALENDAR YEAR 11280.6 30.8 1470 3.0 3.7 22380 3.49 47.58 49 11 4.4 Sep 10 May 14 Mar 24 e2.8 e3.1 e3.8 e3.7 e3.7 e2.8 e2.7 e2.8 e2.7 e2.5 e2.0 e2.1 e2.1 e2.1 e2.8 e3.9 e3.6 e3.6 e3.4 e2.6 e2.6 e2.9 e2.9 e2.1 e2.0 el. 9 el. 8 e2.0 el. 9 e2.0 —— 80.9 2.70 3.9 1.8 160 .31 .34 e2.2 e3.1 e3.1 e2.9 el. 8 el. 6 el. 7 el. 7 e2.3 e2.7 e3.0 e2.0 el. 9 e2.0 el. 8 e2.1 e2.0 el. 9 el. 9 e2.1 e2.3 e2.5 e2.4 e2.3 e2.4 e3.5 e4.5 e3.3 e2.4 e2.3 e2.2 73.9 2.38 4.5 1.6 147 .27 .31 e2.5 e2.4 e2.4 e2.2 e2.1 e2.0 e2.0 e2.0 el. 9 el. 9 el. 7 el. 7 el. 7 el. 7 el. 6 el. 6 el. 6 e3.0 e5.8 e2.8 e2.1 e2.0 e2.3 e2.1 el. 7 el. 8 el. 7 el. 9 el. 8 el. 8 —— 63.8 2.13 5.8 1.6 127 .24 .27 el. 5 el. 5 el. 4 el. 4 el. 4 el. 3 el. 5 elO e3.5 e2.1 el. 8 e8.0 e3.5 e2.2 e2.2 el. 9 el. 9 e2.2 e2.3 e4.0 e5.3 e3.5 e2.3 el. 9 el. 7 el. 6 el. 5 el. 5 el. 5 el. 4 el. 4 79.2 2.55 10 1.3 157 .29 .33 el. 5 el. 5 e4.0 e3.5 e2.2 el. 9 el. 8 e2.9 e7.4 e7.0 eS.O e5.4 e!3 e4.3 eS.O e2.2 el. 7 el. 5 e6.0 e!5 e28 e26 e!3 e6.0 e3.5 e2.3 e2.8 e8.0 e6.0 e3.5 e2.6 194.5 6.27 28 1.5 386 .71 .82 61 e24 e!3 eS.O e3.5 e2.7 e2.3 e2.0 el. 9 e2.6 e2.1 e3.5 e2.4 el. 7 el. 7 el. 6 eS.O e4.9 e4.0 e2.2 e2.3 e3.0 e2.7 ell eS.O e3.8 e3.0 e3.4 e6.0 e4.7 —— 192.0 6.40 61 1.6 381 .73 .81 , BY HATER YEAR (WY) 7.36 27.1 1983 2.45 1974 FOR 1997 2850 7 180 1 1 1530 7 5650 12 14 4 1 19.2 72.9 1985 1.65 1973 HATER YEAR .5 .81 Nov 23 .3 JUl 6 .4 JUl 1 Nov 23 .87 Nov 23 .89 .02 .6 .8 15.1 48.3 1979 2.13 1997 15.3 65.5 1996 1.49 1994 HATER 18. 38. 7. 2440 . 1. 21000 20. 13540 2. 28. 39 8. 2. 21.2 87.5 1979 4.20 1972 YEARS 1964 7 0 04 Sep 61 Jul 0 Jul Oct 20 Oct 12 80 0 9 35.9 132 1975 6.40 1997 - 1997 1979 1994 16 1975 29 1994 9 1994 7 1985 7 1985 e Estimated 390 RIO PORTUGUES BASIN 50115000 RIO PORTUGUES NEAR PONCE, PR—Continued HATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1964 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. IATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1200 15 312 7.9 25.5 1.5 8.3 101 <10 430 410 .997 1005 4.7 332 7.1 21.5 40 9.1 103 <10 210 450 1005 2.1 344 7.5 26.0 20 7.5 93 <10 K680 2400 1010 2.7 392 7.5 26.5 8.7 7.2 91 <10 2000 3300 ALKA- OCT 16 FEB 27 JUN 05 SEP 09 OCT 16 FEB 27 JUN 05 SEP 09 OCT 16 FEB 27 JUN 05 SEP 09 K = HARD- NESS TOTAL (MG/L DATE AS CAC03) (00900) 1996 130 1997 150 200 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 <0.10 1997 ... 0.11 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL DATE (MG/L AS N) (00625) 1996 <0.20 1997 <0.20 0.30 0.40 non-ideal count CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 41 -- 45 53 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 21 -- 21 31 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.97 0.89 0.68 1.5 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.8 -- 9.3 16 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 190 — 218 241 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.3 3.9 3.0 6.5 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 11 -- 13 34 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.48 -- 1.22 1.76 PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 0.020 <0.020 0.110 SODIUM AD- SORP- TION RATIO (00931) 0.4 — 0.5 1.0 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 7 44 18 4 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.4 -- 1.8 4.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.950 0.700 0.380 1.10 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 150 190 180 220 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- 20 — SULFIDE TOTAL (MG/L AS S) (00745) 2.4 -- <0.5 -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.960 0.720 0.380 1.10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 8.9 — 9.7 8.3 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) <0.010 0.030 0.030 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CD (00940) 8.6 — 10 8.4 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 0.27 0.36 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 28 — 391 RIO PORTUOUES BASIN 50115000 RIO PORTUOUES NEAR PONCE, PR—Continued MATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 16... FEB 1997 27... JUN 05... SEP 09... IRON, TOTAL RECOV- ERABLE (UO/L LEAD, TOTAL RECOV- ERABLE (UO/L MANGA- NESE, TOTAL RECOV- ERABLE (UO/L MERCURY TOTAL RECOV- ERABLE (UO/L SELE- NIUM, TOTAL (UO/L SILVER, TOTAL RECOV- ERABLE (UO/L ZINC, TOTAL RECOV- ERABLE (UO/L CYANIDE TOTAL (MO/L PHENOLS TOTAL METHY- LENE BLUE ACTIVE SUB- STANCE AS FE) AS PB) AS MN) AS BO) AS SE) AS AO) AS ZN) AS CN) (UO/L) 220 790 (MO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) 20 <0.10 48 <0.10 <10 <0.010 20 <0.010 <0.01 0.01 392 RIO PORTUOUES BASIN 50116200 RIO PORTUOUES AT PONCE, PR HATER-QUALITY RECORDS LOCATION.--Lat 18°00'20", long 66°36'28", 1,300 ft (400 m) south of Las Anericas Avenue Bridge, 1.2 ml (1.9 km) south of CSC 50115900, 0.8 ml (1.3 km) west of Highways 1 and 2 junction, and 0.7 mi (1.1 km) southeast of Ponce. DRAINAGE AREA.—18.9 mi 2 (49.0 tan'). PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 24... 0845 30 340 7.0 23.5 98 8.1 93 <10 K16000 K18000 FEB 1997 26... 1115 4.5 600 7.2 25.0 4.5 7.2 86 <10 2200 370 MAY 21... 1045 1.2 588 7.8 31.0 2.0 10.9 146 15 2600 K140 SEP 09... 1215 4.0 469 7.7 34.0 10 8.2 116 <10 K1700 560 ALKA- DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 09... DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 09... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 130 -- 180 180 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.18 0.20 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 39 — 48 61 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 18 — 19 22 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 9.0 — 13 6.7 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 187 -- 363 257 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 14 -- 54 18 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 15.2 — 1.14 2.78 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 2 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 204 10 8 22 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 -- 1.5 0.90 NITRO- GEN* NITRATE TOTAL (MG/L AS N) (00620) — 0.080 0.060 0.210 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 120 170 150 120 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.020 <0.010 0.060 0.050 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) — 0.080 0.120 0.260 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 18 -- 85 45 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.050 0.030 0.090 0.070 CHLO- RIDE, DIS- SOLVED (MG/L AS CD (00940) 14 — 51 7.0 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.60 0.28 0.86 0.50 K « non-ideal count OCT 1996 24... FEB 1997 26... MAY 21... SEP 09... RIO PORTUGUES BASIN 50116200 RIO PORTUGUES AT PONCE, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 393 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 0.64 0.31 0.95 0.56 0.64 0.40 1.1 0.82 2.9 0.180 1.8 <0.020 4.7 0.130 3.6 0.040 <1 <1 <100 <100 50 30 <1 <1 <1 DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 09... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 7700 2400 <1 300 240 <0.10 <0.10 <1 <1 <1 <1 20 <0.010 <0.010 <1 <0.01 <0.01 PESTICIDE ANALYSES DATE JUN 1997 05... TIME PCB, TOTAL (UG/L) ALDRIN, TOTAL (UG/L) CHLOR- DANE, TECH- NICAL TOTAL (UG/L) P,P'- P,P'- ENDO- DDD P,P'- DOT DI- DI- SULFAN, UNFILT DDE, UNFILT AZINON, ELDRIN I RECOVER TOTAL RECOVER TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) iuv*/u; luu/u; iuu/ij; vuva/ii/ iuu/ij; luu/u; iuu/ij; iuu/u; vuv»/u; (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) 1125 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 0.010 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) JUN 1997 05... HEPTA- HEPTA- CHLOR CHLOR, EPOXIDE LINDANE TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) MALA- THION, TOTAL (UG/L) (39530) METH- OXY- CHLOR, TOTAL (UG/L) (39480) METHYL PARA- THION, TOTAL (UG/L) (39600) MIREX, TOTAL (UG/L) (39755) (39390) (39398) (39410) (39420) (39340) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE JUN 1997 05... PARA- PCNS THION, UNFILT TOTAL (UG/L) RECOVER (UG/L) PER- THANE TOTAL (UG/L) TOX- TOTAL (UG/L) <0.010 <0.100 <0.100 <1.00 TOTAL TRI- THION (UG/L) (39540) (39250) (39034) (39400) (39786) <0.010 2,4-D, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (39730) (39740) (82183) (39760) 0.120 <0.010 <0.010 <0.010 394 RIO GUAYANILLA BASIN 50124200 RIO GUAYANILLA NEAR GUAYANILLA, PR LOCATION.—Lat 18°02'40", long 66°47'53", Hydrologic unit 21010004, on left bank, 0.7 mi (1.1 km) north of junction of Highways 2 and 132, 0.6 mi (1.0 km) downstream from Quebrada Consejo, 1.8 mi (2.9 km) north-northwest from Plaza de Guayanilla. DRAINAGE AREA.--18.9 mi 2 (49.0 km2 ). PERIOD OF RECORD.—March 1981 to current year. GAGE.—Water-stage recorder. Elevation of gage is 80 ft (24 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR MAY JUN JUL AUG SEP 1 48 40 2 638 28 3 629 22 4 28 19 5 26 16 6 624 15 7 23 30 8 25 16 9 22 45 10 20 34 11 19 30 12 17 69 13 16 52 14 16 27 15 15 19 16 16 17 17 14 64 18 13 112 19 36 67 20 42 51 21 74 54 22 106 62 23 107 77 24 66 52 25 48 642 26 35 638 27 168 634 28 67 632 29 161 629 30 120 625 31 50 —— TOTAL 1489 1218 MEAN 48.0 40.6 MAX 168 112 MIN 13 15 AC -FT 2950 2420 CFSM 2.54 2.15 IN. 2.93 2.40 STATISTICS OF MONTHLY MEAN MEAN 59.4 47.5 MAX 167 110 (WY) 1986 1988 MIN 16.0 17.0 (WY) 1983 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 623 621 620 620 e!9 e!8 el 8 e!8 e!7 e!7 e!8 e!7 e!6 616 e!5 e!4 e!4 e!3 e!3 e!2 e!2 e!2 ell ell e!2 e!4 e!2 e!2 e!3 e!2 e!9 479 15.5 23 11 950 .82 .94 DATA 18.2 41.9 1988 6.72 1994 621 e21 656 636 645 626 632 625 626 624 e!9 e!6 e!5 e25 e!5 e!4 e!2 e!2 ell ell elO e!8 e!4 ell e9.5 e9.0 e9.5 e8.5 68.5 68.0 eS.O 576.0 18.6 56 8.0 1140 .98 1.13 FOR WATER 10.6 27.5 1992 4.21 1994 68.0 69.5 69.5 ell 622 e!5 e!9 e!2 e9.5 eS.O 67.5 e6.5 e6.5 e6.0 66.0 65.5 e5.5 65.5 65.0 65.0 64.8 65.0 64.8 64.5 64.3 64.4 64.4 64.3 —— —— 219.0 7.82 22 4.3 434 .41 .43 YEARS 1981 7.48 11.6 1996 3.10 1990 64.2 64.0 64.0 64.2 64.0 64.0 64.0 64.0 64.2 64.0 63.8 63.6 63.6 63.6 e3.6 63.4 e3.4 64.0 64.2 64.0 e3.6 e3.2 63.0 62.9 62.8 62.8 64.0 67.0 elO e!2 e7.5 136.6 4.41 12 2.8 271 .23 .27 - 1997 6.14 13.2 1989 2.85 1981 FOR 1996 CALENDAR YEAR 8879. 24. 922 2. 3. 17610 1. 17. 52 12 5. 3 3 Sep 10 8 May 7 5 May 12 28 48 1 ell e5.5 64.8 64.4 64.2 63.6 63.2 63.1 63.0 62.8 62.8 62.8 62.7 62.7 62.7 62.6 62.5 62.4 62.4 62.3 62.3 63.5 62.8 62.6 62.5 62.4 62.5 62.5 63.2 63.0 —— 98.8 3.29 11 2.3 196 .17 .19 63.0 63.2 63.3 63.3 62.8 62.6 62.5 62.4 62.3 62.3 62.1 62.1 el. 9 el. 8 el. 7 el. 7 el. 7 el. 7 el. 7 el. 7 el. 9 e2.3 e3.4 eS.O e8.0 67.3 67.8 64.6 63.2 62.6 62.5 94.4 3.05 8.0 1.7 187 .16 .19 e3.6 62.7 62.1 e2.0 el. 9 el. 8 el. 7 el. 7 el. 7 el. 6 el. 6 el. 6 el. 6 el. 6 el. 6 el. 5 el. 6 e9.0 e8.5 3.7 2.1 1.9 el. 8 1.7 1.7 1.8 1.7 1.6 1.6 1.6 —— 70.6 2.35 9.0 1.5 140 .12 .14 1.7 1.6 1.5 1.6 1.7 1.7 3.8 4.4 2.2 1.9 1.9 2.0 2.1 2.0 1.9 1.9 2.2 2.4 2.8 2.9 5.6 66.1 65.0 64.0 e3.7 3.4 3.3 3.0 2.8 2.8 5.2 89.1 2.87 6.1 1.5 177 .15 .18 3.1 2.5 23 14 5.7 4.5 3.9 3.5 3.4 3.3 4.7 3.3 3.9 3.5 3.7 3.1 63.2 63.4 3.5 3.0 2.7 2.9 63.0 63.2 4.5 3.2 2.9 2.9 2.8 14 15 159.3 5.14 23 2.5 316 .27 .31 5.3 9.2 7.3 6.1 4.1 3.4 3.2 2.9 3.2 2.8 2.8 3.5 4.5 3.0 2.9 2.5 2.3 2.2 2.2 2.0 2.1 3.4 2.7 2.3 2.6 2.8 2.5 3.6 6.2 65.1 —— 108.7 3.62 9.2 2.0 216 .19 .21 , BY WATER YEAR (WY) 9.83 26.6 1983 2.76 1995 FOR 1997 4738 13 168 1 1 1500 10 9400 9 31 4 1 25.6 80.4 1985 2.33 1994 WATER YEAR .5 .0 Oct 27 .5 Jun 16 .6 Jun 10 Oct 27 .71 Oct 27 .69 .33 .4 .9 14.1 41.0 1987 2.35 1997 11.8 25.9 1986 2.45 1994 WATER 21. 33. 8. 1500 . 1. 14700 20. 15860 1. 15. 48 9. 3. 17.0 48.5 1988 5.14 1997 YEARS 1981 9 1 94 Oct 77 Jul 1 Sep Sep 40 Sep 16 74 5 2 39.3 102 1981 3.62 1997 - 1997 1986 1994 7 1985 30 1994 4 1994 12 1982 12 1982 e Estimated 395 RIO GUAYANILLA BASIN 50124700 RIO GUAYANILLA AT CENTRAL RUFINA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°00'40", long 66°46'49", at dirt road bridge, 0.7 mi (1.1 Ion) from mouth, 0.9 mi (1.4 km) east of Central Rufina and 0.9 mi (1.4 km) southeast of Guayanilla. DRAINAGE AREA.--22.8 mi* (59.1 km2 ). PERIOD OF RECORD.—Water years 1960-65, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MAY 28 AUG DIS- PH OXYGEN, OXYGEN COLI- CBARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CREM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. IATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1020 56 418 7.8 24.0 6.5 8.1 94 <10 4100 3000 .997 1030 3.0 580 7.4 25.5 7.8 6.4 77 12 460 210 0945 2.0 521 7.1 26.5 4.5 5.9 74 <10 K16000 27000 1115 1.1 940 7.0 30.0 1.6 4.6 61 11 3800 3700 ALKA- DATE NOV 1996 01... MAR 1997 06... MAY 28... AUG 20... DATE NOV 1996 01... MAR 1997 06... MAY 28... AUG 20... DATE NOV 1996 01... MAR 1997 06... MAY 28... AUG 20... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 180 — 170 170 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — 0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.35 0.86 0.72 0.97 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 49 — 42 28 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 19 -- 19 28 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.7 9.0 4.2 21 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 14 — 15 25 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 243 -- 238 234 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 12 40 19 95 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 12 -- 21 13 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 36.5 -- 1.28 0.69 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.130 1.00 0.610 2.50 SODIUM AD- SORP- TION RATIO (00931) 0.4 — 0.7 14 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 22 <1 20 <:L ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- 2 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 -- 2.4 3.8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 2.30 8.10 3.50 20.0 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- 100 -- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 150 130 160 210 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.040 0.040 0.070 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- 70 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 2.30 8.10 3.50 20.0 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 40 -- 41 27 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.080 0.060 0.060 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 — 1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 17 — 20 19 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.32 0.79 0.66 0.90 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K • non- ideal count 396 RIO GUAYANILLA BASIN 50124700 RIO GUAYANILLA AT CENTRAL RUFINA, PR—Continue WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 01... MAR 1997 06... MAY 28... AUG 20... IRON, TOTAL RECOV- ERABLE (OG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (OG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (OG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (OG/L AS H6) (71900) SELE- NIUM, TOTAL (U6/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (U6/L AS A6) (01077) ZINC, TOTAL RECOV- ERABLE (U6/L AS ZN) (01092) CYANIDE TOTAL (M6/L AS CN) (00720) PHENOLS TOTAL (U6/L) (32730) METHY- TLEMK BLUE ACTIVE SUB- STANCE (MG/L) (38260) 1100 560 <1 60 48 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.03 PESTICIDE ANALYSES CHLOR- DATE MAY 1997 28... TIME 0945 PCB, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) DANE, TECH- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFILT RECOVER (UG/L) (39360) P,P'- DDE, TOTAL (UG/L) (39365) P,P'- DDT UNFILT RECOVER (UG/L) (39370) DI- AZINON, TOTAL (UG/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UG/L) (39388) <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) MAY 1997 28... HEPTA- HEPTA- CHLOR CHLOR, EPOXIDE LINDANE TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) MALA- THION, TOTAL (UG/L) (39530) METH- OXY- CHLOR, TOTAL (UG/L) (39480) METHYL PARA- THION, TOTAL (UG/L) (39600) MI REX, TOTAL (UG/L) (39755) (39390) (39398) (39410) (39420) (39340) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE MAY 1997 28... PARA- THION, TOTAL (UG/L) (39540) PCNS UNFILT RECOVER (UG/L) (39250) PER- THANE TOTAL (UG/L) (39034) TOX- APHENE, TOTAL (UG/L) (39400) TOTAL TRI- THION (UG/L) (39786) 2,4-D, TOTAL (UG/L) (39730) 2,4,5-T TOTAL (UG/L) (39740) 2, 4-DP TOTAL (UG/L) (82183) SILVEX, TOTAL (UG/L) (39760) <0.010 <0.100 <0.100 <1.00 <0.010 <0.010 <0.010 <0.010 <0.010 RIO YAUCO BASIN 50125780 LAGO LUCCHETTI AT DAMSITE NEAR YAUCO, PR 397 LOCATION.--Lat 18°05'37", long 66°51'54, Hydrologic Unit 21010004, at Antonio Lucchetti Dam on Rio Yauco, 3.9 mi (6.3 km) north of Yauco. DRAINAGE AREA.--17.4 mi 2 (45.1 km1 ). ELEVATION RECORDS PERIOD OF RECORD.—December 1989 to current year. Prior to October 1994, published as Lago Lucchetti at Damsite. GAGE.—Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Lucchetti was completed in 1952. The dam is on Rio Yauco and is a unit of the Southwestern Puerto Rico Project. It provides 16,500 acre-feet (20.3 hm3 ) of usable storage for power generation and irrigation. The dam is a concrete gravity structure with a total length of 591 ft (180 m), a maximum height of 178 ft (54 m), and a maximum width at the base of 150 ft (46 m). An ungated, overflow tupe spillway with a clear length of 171 ft (52 m), and a maximum capacity of 62,800 ftVs (1,778 mVs) at a design head of 20 ft (6 m). The dam is owned by Puerto Rico Electric Power Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 572.19 ft (174.40 m), May 27, 1993; minimum elevation, 512.09 ft (156.08 m), Sept. 9, 1994. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 570.08 ft (173.76 m), Nov. 4, minimum elevation, 524.29 ft (159.80 m), Aug. 21. Capacity Table (based on data from Puerto Rico Hater Resources Authority) Elevation, in feet 512 520 525 527 530 532 Contents, in acre-feet 1,505 2,385 2,965 3,255 3,695 3,975 Elevation, in feet 540 550 561 563 571 573 Contents, in acre-feet 5,165 7,020 9,600 10,125 12,125 12,645 ELEVATION (FEET NGVD), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN OCT NOV DEC 566.68 A 563.93 562.64 561.15 A 559.05 557.48 555.76 553.96 551.76 549.90 549.56 547.72 547.80 547.79 548.28 548.14 548.32 548.48 550.54 553.97 555.16 556.85 557.42 559.57 562.30 566.08 566.39 567.51 568.00 568.00 547.72 1996 1997 569.14 569.58 570.00 569.06 569.27 567.82 566.87 565.58 565.36 567.37 567.44 567.95 568.25 566.68 564.63 564.68 565.68 566.52 566.60 565.69 564.85 563.78 563.58 562.91 562.63 562.11 562.15 562.37 561.67 562.17 --- 570.00 561.67 MAX 570.83 MAX 570.00 562.33 562.46 562.19 561.36 560.81 559.98 559.13 559.24 559.33 559.24 559.36 559.52 559.59 559.88 560.04 559.42 559.52 559.69 559.51 559.70 560.01 560.74 561.43 561.60 561.63 561.61 A 561.06 561.07 560.22 560.28 562.46 559.13 MIN 547 MIN 524 560.30 560.45 560.55 560.63 561.04 561.38 561.25 560.12 559.77 560.67 561.07 561.29 561.69 561.13 560.39 560.33 560.33 560.13 560.13 559.59 559.49 559.45 559.48 558.92 558.92 558.61 556.95 557.00 557.00 557.01 556.96 561.69 556.95 .72 .30 FEB 556.95 556.87 556.86 558.21 558.93 559.22 559.48 559.47 559.46 559.44 559.41 559.37 559.64 560.26 560.30 561.58 561.66 561.71 562.80 563.67 563.58 563.54 563.55 563.52 563.44 562.67 562.68 562.21 563.67 556.86 MAR 562.17 562.13 562.05 561.97 561.89 561.36 560.72 560.69 560.64 560.15 559.98 A A 559.44 559.37 559.40 559.43 A 558.12 A A 559.07 560.44 560.58 560.70 A 560.66 560.69 560.67 560.77 559.84 562.17 558.12 APR 560.77 561.46 561.65 561.59 561.56 561.47 561.41 560.80 A A 560.95 561.01 560.95 560.88 560.73 560.55 560.67 560.07 560.57 560.74 560.87 561.09 560.49 560.60 559.91 559.84 559.82 559.76 558.85 558.98 561.65 558.85 MAY 558.03 558.85 558.99 558.93 559.07 558.08 558.46 558.76 558.57 559.37 559.52 560.17 560.26 560.44 561.07 560.51 560.44 560.76 561.11 561.07 561.01 561.05 560.42 559.56 559.50 559.45 559.79 560.22 559.50 559.44 559.38 561.11 558.03 JUN 559.34 559.87 560.37 561.29 561.44 561.47 A A A A A A A A A A 559.65 A 559.25 558.92 557.99 557.91 557.15 556.01 555.93 554.43 554.02 553.94 553.85 552.67 561.47 552.67 JUL 551.69 551.52 549.30 546.95 546.88 546.79 545.30 544.46 544.37 543.55 543.16 543.08 543.01 541.59 539.74 539.69 539.60 537.77 537.78 537.75 537.83 537.81 537.73 536.40 535.06 534.97 534.87 534.76 534.64 A 534.79 551.69 534.64 AUG 534.42 A 535.68 535.82 533.50 533.08 532.71 532.70 532.65 532.76 532.74 531.01 531.18 529.76 527.78 527.76 527.75 527.39 527.61 524.30 527.12 528.64 528.81 528.92 525.73 526.17 527.90 527.89 524.84 525.30 525.84 535.82 524.30 SEP 526.28 526.98 528.97 530.08 532.09 534.52 534.46 536.07 536.29 538.48 539.73 540.27 540.23 540.22 538.00 537.96 536.24 536.17 534.62 534.53 534.44 531.60 530.53 528.44 528.43 528.37 528.30 528.26 528.76 529.98 540.27 526.28 A No gage-height record 398 RIO LOCO BASIN 50128900 LAGO LOCO AT DAMSITE NEAR YAUCO, PR LOCATION.--Lat 18°02'41", long 66°53'16", Hydrologic Onit 21010004, at Damaite, 2.60 mi (4.18 km) northwest from Yauco plaza, 0.45 mi (0.72 km) northeast from Escuela Rio Cafias and 0.95 mi (1.53 km) northwest from Escuela Susua Alta. DRAINAGE AREA.--8.40 mi 2 (21.8 km2 ). PERIOD OF RECORD.—May 1995 to current year. ELEVATION RECORDS GAGE. — Water stage recorder. Datum of gage is mean sea level. REMARKS. — Lago Loco was completed in 1951. The dam is a concrete gravity structure with a total lenght of 600 ft (183 m), maximum structural height of 72 ft (21.9 m), the ungated overflow spillway is 150 ft (47.7 m) long with crest at elevation of 230 ft (70.1 m) . It has a normal storage capacity of 1,950 acre-feet (2.40 hm1 ) as for May 4, 1979. The Loco Dam is owned by the Puerto Rico Electric Power Authority (P.R.E.P.A) and its part of the Southwestern Puerto Rico Project which was developed for electric power generation and irrigation of the lands in the Lajas Valley, some of the Project waters are used for water supply in the Lajas area. The maximum drawdown of the Dam is from 230 ft (70.1 m) to 220 ft (67.1 m) and the Capacity Table provided by P.R.E.P.A includes only that portion of the storage for the dam. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.— Maximum elevation, 231.95 ft (70.7 m) , Nov. 18, 1997; minimum elevation, 217.77 ft (66.4 m), June 10, 1997. EXTREMES OBSERVED FOR CURRENT YEAR .- -Maximum elevation, 231.95 ft (70.7 m) , Nov. 18; minimum elevationm, June 10. 217.77 ft (66.4 m) Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 220 225 Contents, in acre-feet 0 299 Elevation, in feet 230 232 Contents, in acre-feet 639 787 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN OCT ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES NOV DEC JAN FEB MAR APR MAY JUN JUL AU6 SEP 230.45 A 230.28 230.41 230.42 230.88 230.34 230.36 230.33 230.39 230.95 230.33 230.34 230.25 229.34 228.02 226.17 225.96 226.17 225.96 230.32 230.70 230.93 230.37 230.30 230.35 A 230.34 A A 230.53 230.24 230.48 230.20 230.50 230.13 231.05 230.50 230.41 A A A 230.67 A A A A A A A A A 231.03 A 230.75 A 230.39 A 230.09 230.40 230.06 —— 230 230 230 230 230 230 230 230 229 229 229 230 A A 229.22 .32 230.25 229 .38 230.71 229 .34 230.16 229 .48 A 228 .67 A A .19 229. .40 229. .34 .85 A A A A .59 A A A A A .49 A A A A .20 A 230 229 .81 .52 .17 .74 .12 .75 229.49 9 229 6 229 229 230 229 229 228 228 229 229 228 227 230 229 230 230 230 230 230 A 229.63 A 229.51 .23 .90 .83 .00 .55 .25 .96 .63 .11 .14 .09 .08 .32 .92 .41 A A A A A A A 226.03 228.81 A A A A A A A A A A A 226.84 225.55 227.53 .01 229.11 225.19 .24 227.57 228.84 .34 226.44 228.01 .28 A A A A 224.91 A 226.42 —— A 224.67 —— A —— 226.22 227.65 227.01 225.69 224.52 226.06 A 226.13 227.25 230.53 230.23 230.03 227.92 228.25 229.77 229.79 228.68 229.78 229.39 226.54 227.18 226.68 226.80 228.86 227.52 226.01 225.54 225.19 225.27 223.25 222.41 A 223.68 224.80 226.82 223.71 223.39 224.09 223.22 219.32 217.77 219.75 221.08 222.05 222.77 223.96 224.28 224.29 224.06 223.71 223.88 227.16 226.51 227.36 228.12 224.89 227.32 226.58 225.46 224.24 225.98 —— 226.36 222.62 229.07 229.89 228.88 227.80 229.47 229.11 226.60 226.21 226.11 225.87 225.52 227.49 229.50 227.42 224.65 228.93 228.63 228.33 228.15 226.92 A 227.15 229.87 229.49 229.14 228.78 226.99 223.96 222.69 226.75 226.51 226.52 A 230.16 229.72 A 227.58 227.32 227.05 225.42 226.76 223.43 223.76 227.14 226.78 226.43 228.72 226.15 229.70 227.26 A 225.62 A 230.00 229.14 226.91 224.99 229.63 A A A 228.98 226.69 229.91 229.13 A A 229.45 230.31 228.02 226.81 225.48 224.98 224.10 228.76 226.27 228.48 226.15 228.82 228.45 227.96 230.80 229.90 229.92 227.20 225.40 224.61 223.76 228.91 227.19 —— A No gage-height record LOCATION.—Lat 17°58'33' Bnsenada. RIO LOCO BASIN 399 50129700 RIO LOCO AT GUANXCA, PR WATER-QUALITY RECORDS long 66°54'52", 0.6 mi (1.0 km) northwest of Guanica and 1.2 mi (1.9 km) northeast of DRAINAGE AREA.—Indeterminate. PERIOD OF RECORD.—Water years 1975 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MAY 28 ADG )ATE TIME PH OXYGEN, OXYGEN COLI- SPE- WATER DIS- DEMAND, FORM, STREP - CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER (OS/CM) UNITS) (DEG C) (NTU) (MG/L) ATI ON) (MG/L) 100 ML) 100 ML) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 .997 ... ... DATE NOV 1996 01... MAR 1997 05... MAY 28... AUG 20... DATE NOV 1996 01... MAR 1997 05... MAY 28... AUG 20... DATE NOV 1996 01... MAR 1997 05... MAY 28... AUG 20... 0900 1010 1100 1000 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 110 — 2900 680 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- 0.47 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.38 0.36 0.48 0.30 298 1010 28000 33000 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 — 210 90 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 22 — 12 68 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.5 1.1 0.66 0.40 6.7 27 7.1 25 7.1 30 7.0 31 MAGNE- SIUM, SODIUM, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS MG) AS HA) (00925) (00930) 12 12 __ 573 4520 110 855 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 174 — 15600 1570 NITRO- PHOS- GEN, PHORUS TOTAL TOTAL (MG/L (MG/L AS N03) AS P) (71887) (00665) 6.9 0.060 4.8 0.070 2.9 0.120 1.8 0.100 .0 19 .5 3 .0 2 .0 4 SODIUM AD- SORP- TION RATIO (00931) 0.5 -- 37 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 14 11 34 40 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- 1 -- 4.0 49 <10 510 K1900 .9 4.5 55 11 K880 710 .9 5.4 79 50 3300 670 .9 5.9 88 <10 K100 490 ALKA- POTAS- LINITY CHLO- SIUM, WAT WH SULFATE RIDE, DIS- TOT PET SULFIDE DIS- DIS- SOLVED FIELD TOTAL SOLVED SOLVED (MG/L MG/L AS (MG/L (MG/L (MG/L AS K) CACO3 AS S) AS SO4) AS CL) (00935) (00410) (00745) (00945) (00940) 2.9 110 <0.5 16 17 130 170 260 <0.5 1300 8600 38 210 — 110 180 NITRO- NITRO- NITRO- NITRO- NITRO- GEN* GEN* GEN/ GEN* GEN* NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC TOTAL TOTAL TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L (MG/L (MG/L AS N) AS N) AS N) AS N) AS N) (00620) (00615) (00630) (00610) (00605) 1.20 <0.010 1.20 0.050 0.34 0.710 0.010 0.720 0.060 0.30 0.180 0.010 0.190 0.040 0.43 0.010 <0.010 <0.020 0.030 0.25 CHRO- BARIUM, BORON, CADMIUM MIUM, COPPER, TOTAL TOTAL WATER TOTAL TOTAL RECOV- RECOV- UNFLTRD RECOV- RECOV- ERABLE ERABLE TOTAL ERABLE ERABLE (UG/L (UG/L (UG/L (UG/L (UG/L AS BA) AS B) AS CD) AS CR) AS CU) (01007) (01022) (01027) (01034) (01042) <100 40 <1 3 <10 — 200 2200 <10 4 32 -- K » Non- ideal count 400 RIO LOCO BASIN 50129700 RIO LOCO AT GUANICA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996TO SEPTEMBER 1997 DATE IRON, TOTAL RECOV- ERABLE (UG/L AS PE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELR— NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LEN& BLUE ACTIVE SUB- STANCE (MG/L) (38260) NOV 1996 01... MAR 1997 05... MAY 28... AUG 20... 830 260 <1 40 240 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.06 PESTICIDE ANALYSES DATE TIME PCS, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFILT RECOVER (UG/L) (39360) P,P'- DDE, TOTAL (UG/L) (39365) P,P'- DDT UNFILT RECOVER (UG/L) (39370) DI- AZINON, TOTAL (UG/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UG/L) (39388) MAY 1997 28... 1100 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) MAY 1997 28... HEPTA- METH- HEPTA- CHLOR MALA- OXY- CHLOR, EPOXIDE LINDANE THION, CHLOR, TOTAL TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) METHYL PARA- THION, MIREX, TOTAL TOTAL (UG/L) (UG/L) (39390) (39398) (39410) (39420) (39340) (39530) (39480) (39600) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE PARA- THION, TOTAL (UG/L) (39540) PCNS UNFILT RECOVER (UG/L) (39250) PER- THANE TOTAL (UG/L) (39034) TOX- APHENE, TOTAL (UG/L) (39400) TOTAL TRI- THION (UG/L) (39786) 2,4-D, TOTAL (UG/L) (39730) 2,4,5-T TOTAL (UG/L) (39740) 2, 4-DP TOTAL (UG/L) (82183) SILVEX, TOTAL (UG/L) (39760) MAY 1997 28... <0.010 <0.100 <0.100 <1.00 <0.010 <0.010 <0.010 <0.010 <0.010 01 23456 KILOMETERS L.....1.....,..]...........{........i......_.i......._.i..... 01234 MILES ..-^•-A _x^—^^" I R " EXPLANATION A 138° SURFACE-WATER STATION AND NUMBER 1297 QUAUTY-OF-WATER STATION AND NUMBER 1364 r»Aii v SEDIMENT STATION AND NUMBER 143 WELL ANP WELL NUMBER CARIBBEAN SEA Figure 24.--Rio Guanajibo basin. 402 RIO OUANAJIBO BASIN 50131990 RIO OUANAJIBO AT HWY 119 AT SAN GERMAN, PR LOCATION.—Lat I8e 05'06", long 67»02'02", Hydrologic Unit 21010003, on left bank, at bridge on Bwy 119, 0.6 mi (1.0 km) southwest of junction of Highways 119 and 2, 0.2 mi (0.3 km) northeast of junction of Highways 119 and 102, 0.7 mi (1.1 km) east from public Plasa of San German. DRAINAGE AREA.—34.6 mi* (89.6 km1 ). PERIOD or RECORD.--April 1991 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 148 ft (45 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHAROI DAY OCT NOV 1 83 147 2 187 60 3 125 42 4 54 42 5 42 34 6 36 32 7 33 73 8 30 241 9 28 152 10 26 98 11 25 68 12 23 519 13 23 248 14 23 91 15 21 63 16 20 54 17 19 100 18 19 269 19 20 124 20 22 95 21 79 414 22 159 151 23 186 174 24 121 125 25 47 100 26 27 75 27 198 60 28 412 55 29 187 54 30 88 50 31 197 TOTAL 2560 3810 MEAN 82.6 127 MAX 412 519 MXN 19 32 MED 36 93 AC-FT 5080 7560 CFSM 2.39 3 . 67 IN. 2.75 4.10 STATISTICS OF MONTHLY MEAN MEAN 89.0 72.2 MAX 205 127 (WY) 1993 1997 MXN 20.4 15.8 (WY) 1992 1992 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS E, GUI DEC 48 48 43 36 35 36 37 33 32 29 31 25 24 23 24 23 21 19 19 18 18 17 16 16 16 17 16 20 19 25 70 854 27.5 70 16 24 1690 .80 .92 DATA 25.4 52.2 1993 8.21 1992 FOI IIC FEET FER JAN 31 286 122 95 122 88 110 48 42 37 33 31 35 42 27 25 23 21 22 19 19 24 22 20 19 21 19 18 17 16 17 1471 47.5 286 16 25 2920 1.37 1.58 FOR MATER T 24.6 47.5 1997 9.87 1996 t 1996 CALENI 18722.2 51.2 659 4.9 6.2 37140 1.48 20.13 130 22 7.5 SECOND, 1 DAILY FEB 19 23 24 33 48 27 22 20 18 17 16 14 14 13 13 12 12 11 12 11 11 11 11 10 10 9.9 9.6 9.5 —— —— —— 461.0 16.5 48 9.5 13 914 .48 .50 BARS 1991 18.7 36.5 1995 4.32 1992 BAR YEAR Sep 10 Feb 17 Mar 23 IATER Y MEAN V MAR 9.7 9.5 9.6 9.5 9.0 9.0 8.9 9.3 9.2 9.0 8.3 7.8 7.9 8.0 8.1 8.1 8.0 11 8.7 8.6 8.2 8.0 7.6 7.3 7.1 7.5 12 14 52 21 14 335.9 10.8 52 7.1 8.9 666 .31 .36 - 1997 11.6 25.8 1995 3.52 1992 EAR OCTO ALUES APR 14 13 11 11 9.1 8.1 8.3 7.8 7.4 7.1 7.2 6.8 7.3 6.4 5.9 7.0 •6.2 e5.6 •5.5 •5.5 elO •12 •5.9 •5.1 •6.0 •6.2 •7.2 •8.6 •6.7 e5.9 —— 233.8 7.79 14 5.1 7.1 464 .23 .25 , BY NAT 21.5 55.9 1996 7.79 1997 FOR 1997 11268 30 519 3 3 2540 9 22350 12 75 11 4 BER 1996 TO i MAY •6.6 •61 •45 •12 •9.0 e6.8 •5.4 •7.8 •7.3 •7.2 •7.0 •6.0 eS.O .4 .4 .9 .8 .8 .5 .8 5.0 8.8 5.7 11 12 5.7 5.0 5.5 4.8 4.5 4.8 291.5 9.40 61 4.4 5.7 578 .27 .31 ER YEAR (WY) 40.2 72.0 1995 5.11 1994 WATER YEAR .0 .9 Nov 12 .1 Jun 10 .7 Jun 8 Jan 2 .99 Jan 2 .89 .11 .5 SEPTEMBE JUN 5.6 .1 .8 .3 .0 .7 .5 3.4 3.3 3.1 3.5 3.4 4.7 4.4 4.4 4.5 4.0 8.5 18 9.5 6.3 5.5 .7 .2 .8 .8 .9 .4 .5 .2 —— 155.0 5.17 18 3.1 4.5 307 .15 .17 18.6 46.3 1993 3.91 1994 X 1997 JUL 6.3 4.9 4.4 4.3 4.0 4.1 4.8 15 6.3 4.9 4.9 5.0 6.9 5.8 4.3 5.5 4.8 4.6 14 16 8.6 13 7.7 5.8 4.7 4.6 4.4 3.7 3.8 8.7 24 219.8 7.09 24 3.7 4.9 436 .20 .24 17.9 37.6 1995 6.68 1994 WATER 37. 58. 16. 913 1. 1. 6610 13. 27120 1. 14. 85 15 4. AUG 8.2 6.7 26 38 16 9.0 7.3 6.3 5.8 10 33 12 8.8 77 69 20 12 9.5 18 10 8.7 7.1 9.3 21 22 8.6 7.0 5.7 6.3 11 32 541.3 17.5 77 5.7 10 1070 .50 .58 39.5 109 1995 17.2 1994 YEARS 1991 - 4 6 6 Sep 16 5 May 9 8 May 6 Jan 6 23 Jan 6 08 70 a SEP 11 29 15 35 16 12 8.7 7.1 7.2 6.3 5.3 6.4 8.4 5.5 5.3 4.6 4.1 3.6 4.4 3.9 4.1 4.5 9.1 5.1 6.0 5.6 4.4 4.1 76 17 ___ 334.7 11.2 76 3.6 6.2 664 .32 .36 55.1 119 1995 11.2 1997 1997 1995 1994 1995 1992 1992 1992 1992 e Estimated 403 RIO GUANAJIBO BASIN 50133600 RIO GUANAJIBO NEAR SAN GERMAN, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°07'18", long 67°03'56", at bridge on Highway 347, 2.2 mi (3.5 km) northwest of San German. DRAINAGE AREA.--45.5 mi' (117.8 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. WATER QUALITY DATA, WATER YEARS OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEC C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) NOV 1996 12... 1100 76 369 6.6 24.5 3.5 7.3 86 <10 K2200 320 MAR 1997 05... 1130 25 705 6.9 24.5 0.60 4.8 57 13 K73 K140 MAY 28... 1310 8.6 835 7.3 29.0 5.6 4.5 59 39 2700 510 AUG 19... 1100 20 617 6.9 27.0 4.4 4.2 52 15 400 270 ALKA- DATE NOV 1996 12... MAR 1997 05... MAY 28... AUG 19... DATE NOV 1996 12... MAR 1997 05... MAY 28... AUG 19... DATE NOV 1996 12... MAR 1997 05... MAY 28... AUG 19... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 180 -- 280 200 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — 0.63 0.31 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.46 1.5 2.4 2.0 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 19 — 26 21 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 35 -- 37 35 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.7 3.6 3.8 3.7 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 32 -- 52 36 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 230 -- 571 367 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 7.3 16 17 17 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 13 — 132 42 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 47.2 — 13.3 19.8 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.200 0.550 0.940 0.630 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- 3 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 14 3 6 <1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.6 — 12 6.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 1.90 1.20 1.60 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- 100 -- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 160 300 280 240 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.060 0.190 0.150 0.160 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 70 -- 400 __ SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 1.20 2.10 1.40 1.80 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 16 -- 64 43 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.190 0.750 1.50 1.20 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 12 — 2 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CD (00940) 16 -- 80 39 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.28 0.71 0.86 0.81 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- 12 -- K - non-ideal count 404 RIO GOANAJIBO BASIN 50133600 RIO GUANAJIBO NEAR SAN GERMAN, PR—Continued WATER QUALITY DATA, WATER YEARS OCTOBER 1996 SEPTEMBER 1997 DATE NOV 1996 12... MAR 1997 05... MAY 28... AUG 19... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) SELE- NIUM, TOTAL (UG/L AS SE) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) CYANIDE TOTAL (MG/L AS CN) PHENOLS TOTAL (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 460 280 40 130 <0.10 <0.10 <1 <1 <1 <1 <0.010 20 <0.010 <1 <1 METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 0.08 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR 405 LOCATION.--Lat 18°09'36", long 67°05'08' southwest of Rosario plaza. DRAINAGE AREA.—18.3 mi 2 (47.4 km2 ). Hydrologic Dnit 21010003, at bridge on Highway 348, 0.5 mi (0.8 km) WATER-DISCHARGE RECORDS PERIOD OF RECORD.--October 1985 to current year. GAGE.--Water-stage recorder. Elevation of gage is 50.0 ft (15.2 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES NOV DEC JAN FEB APR MAY JUN AUG SEP 1 75 120 2 67 100 3 131 85 4 97 76 5 74 81 6 69 75 7 62 76 8 61 72 9 59 123 10 60 137 11 51 106 12 51 147 13 49 125 14 69 91 15 51 78 16 46 72 17 43 109 18 44 108 19 45 85 20 47 88 21 122 99 22 80 87 23 57 79 24 50 72 25 47 66 26 44 62 27 71 58 28 74 57 29 178 55 30 130 53 31 86 TOTAL 2190 2642 MEAN 70.6 88.1 MAX 178 147 MIN 43 53 AC-FT 4340 5240 CFSM 3.86 4.81 IN. 4.45 5.37 STATISTICS OF MONTHLY MEAN MEAN 102 70.8 MAX 206 117 (WY) 1986 1990 MIN 33.2 16.1 (WY) 1992 1992 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 52 48 47 45 44 42 41 40 38 37 44 38 36 35 35 35 34 34 34 33 33 33 33 35 35 40 34 33 35 35 34 1172 37.8 52 33 2320 2.07 2.38 DATA 32.3 53.7 1995 9.92 1992 FOR 32 35 71 66 57 40 40 37 53 47 37 34 33 36 34 32 31 31 31 36 50 103 52 35 29 27 26 25 23 23 25 1231 39.7 103 23 2440 2.17 2.50 26 35 27 27 24 52 45 26 25 24 25 22 21 21 20 20 20 19 19 19 19 19 18 18 18 19 19 18 _-- ___ —— 665 23.8 52 18 1320 1.30 1.35 FOR WATER YEARS 1986 23.1 39.7 1997 15.1 1994 19.7 37.8 1995 8.55 1992 18 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 16 16 16 19 16 15 15 15 14 15 15 20 21 21 24 536 17.3 24 14 1060 .94 1.09 - 1997 22.0 77.0 1989 10.1 1992 1996 CALENDAR YEAR 18040.8 49.3 262 8.6 9.3 35780 2.69 36.67 107 38 15 May 19 Mar 25 Mar 23 29 17 16 15 13 13 13 13 12 12 12 12 12 12 11 11 11 11 11 11 12 14 19 14 12 12 14 12 11 11 --- 398 13.3 29 11 789 .72 .81 , BY WATER 24.2 57.7 1989 11.9 1991 11 14 20 14 11 14 11 9.7 10 13 9.6 9.4 8.8 8.4 8.3 8.7 9.0 9.2 9.5 9.4 10 15 18 34 43 45 25 17 12 11 10 458.0 14.8 45 8.3 908 .81 .93 YEAR (WY) 44.5 122 1993 14.8 1997 10 9.3 9.1 9.1 8.8 8.5 8.6 8.8 8.9 8.7 8.9 9.1 9.1 10 10 11 12 19 73 32 37 83 38 21 127 72 38 26 30 29 784.9 26.2 127 8.5 1560 1.43 1.60 42.8 91.1 1993 12.0 1992 FOR 1997 WATER YEAR 14124.9 38.7 258 8.3 8.7 4340 11.40 8.2 28020 2.11 28.71 79 30 11 Sep 29 May 15 Jun 5 Sep 29 Sep 29 May 14 25 19 17 15 20 35 33 136 53 27 20 18 23 19 17 16 14 39 31 28 23 21 20 16 32 29 18 16 15 15 17 827 26.7 136 14 1640 1.46 1.68 41.9 75.2 1989 23.2 1990 WATER 47. 70. 30. 1550 3. 4. 7480 13. 3. 34600 2. 35. 110 28 11 16 18 50 47 25 19 17 24 39 71 101 65 122 112 127 90 59 66 60 49 41 37 47 53 40 33 30 32 131 82 65 1768 57.0 131 16 3510 3.12 3.59 60.1 102 1989 25.1 1991 YEARS 1986 - 8 6 8 Oct 7 9 May 9 2 May 6 Aug 24 64 Aug 24 7 May 9 61 46 58 56 58 49 39 37 33 30 35 28 26 32 29 41 31 24 22 22 22 24 36 47 44 79 46 31 27 26 258 163 —— 1453 48.4 258 22 2880 2.65 2.95 88.2 157 1993 32.7 1986 1997 1993 1992 1985 1992 1992 1988 1988 1992 406 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1979 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October 1985 to current year. INSTRUMENTATION.—US D-49 sediment sampler since October 1985. Automatic sediment sampler since 1986. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATIONS: Maximum daily mean, 8,150 mg/L October 7, 1985; Minimum daily mean, 1.0 mg/L several days. SEDIMENT LOADS: Maximum daily, 74,700 tons (67,800 tonnes) October 7, 1985; Minimum daily, 0.05 ton (0.04 Tonne) several days. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATIONS: Maximum daily mean, 685 mg/L October 29, 1996; Minimum daily mean, 4.0 mg/L April 20, 1997. SEDIMENT LOADS: Maximum daily, 1,950 tons (1,770 tonnes) September 29, 1997; Minimum daily 0.12 ton (0.11 tonne) April 20, 1997. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 NOV 12 MAR 05 MAY 29 AUO 19 DATE 1996 ... 1997 ... ... ... DATE NOV 1996 12... MAR 1997 05... MAY 29... AU6 19... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1235 72 1245 17 0950 13 1300 57 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 120 — 120 110 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 19 — 24 19 273 275 277 250 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 18 — 14 16 6.7 7.3 7.2 7.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 6.0 — 7.8 7.0 23.5 3 23.5 0 24.5 3 26.0 38 SODIUM AD- SORP- TION RATIO (00931) 0.2 __ 0.3 0.3 .7 .50 .5 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.5 -_ 1.7 1.7 7.9 9.8 7.7 7.4 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 120 150 140 120 92 114 93 91 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -_ <0.5 — 12 <10 <10 3900 810 60 440 240 660 <10 K6700 960 SULFATE DIS- CHLO- RIDE, DIS- SOLVED SOLVED (MG/L AS S04) (00945) 6.2 -- 7.6 7.0 (MG/L AS CL) (00940) 6.5 — 8.9 7.2 DATE NOV 1996 12... MAR 1997 05... MAY 29... AUG 19... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- 0.10 <0.10 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 32 — 27 28 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 161 — 149 158 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 31.5 -- 5.23 24.3 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 11 4 13 33 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.980 0.630 0.700 0.980 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 <0.010 NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.990 0.640 0.710 0.980 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) <0.010 0.020 0.040 0.020 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 <0.20 <0.20 K » non-ideal count RIO GUANAJIBO BASIN 407 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR—Continued WATER QUALITY DATA, WATER YEARS OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 12... MAR 1997 05... MAY 29... AUG 19... DATE NOV 1996 12... MAR 1997 05... MAY 29... AUG 19... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 <0.20 0.23 0.22 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 360 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.2 0.73 0.94 1.2 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) <1 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.2 3.2 4.2 5.3 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) 20 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 0.070 0.090 0.050 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) <0.10 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — SELE- NIUM, TOTAL (UG/L AS SE) (01147) <1 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) <1 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 30 — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) <10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — CYANIDE TOTAL (MG/L AS CN) (00720) <0.010 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 11 — 3 — PHENOLS TOTAL (UG/L) (32730) 3 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 220 <1 21 <0.10 <1 <1 <0.010 <1 <0.01 408 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMZOBEROS, PR— Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MO/L) (TONS/DAY) (CFS) (MO/L) (TONS/DAY) (CPS) (MO/L) (TONS/DAY) OCTOBER NOVEMBER DECEMBER 1 75 31 6.3 120 244 145 52 10 1.5 2 67 14 2.5 100 107 31 48 7 .97 3 131 316 325 85 74 19 47 7 .82 4 97 99 27 76 72 15 45 6 .74 5 74 46 9.2 81 112 30 44 6 .66 6 69 29 5.4 75 37 7.8 42 5 .58 7 62 18 3.0 76 34 8.6 41 5 .57 8 61 14 2.2 72 31 6.3 40 5 .59 9 59 11 1.8 123 300 239 38 6 .59 10 60 9 1.5 137 326 217 37 6 .59 11 51 8 1.0 106 117 36 44 19 2.4 12 51 6 .88 147 453 347 38 16 1.7 13 49 6 .79 125 150 56 36 11 1.1 14 69 68 37 91 35 8.8 35 10 .91 15 51 24 3.3 78 20 4.3 35 10 .93 16 46 10 1.2 72 14 2.6 35 11 .99 17 43 9 .99 109 126 68 34 8 .76 18 44 9 1.1 108 89 28 34 6 .52 19 45 14 1.9 85 39 9.0 34 7 .60 20 47 29 3.7 88 75 23 33 9 .80 21 122 323 332 99 66 18 33 10 .89 22 80 120 28 87 17 4.1 33 10 .89 23 57 93 14 79 13 2.8 33 10 .90 24 50 60 8.1 72 10 1.9 35 10 .94 25 47 28 3.5 66 8 1.4 35 11 1.0 26 44 12 1.4 62 10 1.7 40 17 1.9 27 71 60 23 58 9 1.4 34 12 1.1 28 74 131 26 57 8 1.2 33 10 .93 29 178 685 1050 55 7 1.1 35 9 .89 30 130 311 176 53 12 1.7 35 9 .82 31 86 60 14 —— —— —— 34 8 .74 TOTAL 2190 —— 2111.76 2642 —— 1336.7 1172 —— 29.32 RIO GOANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGDEROS, PR-- Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 409 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 32 35 71 66 57 40 40 37 53 47 37 34 33 36 34 32 31 31 31 36 50 103 52 35 29 27 26 25 23 23 25 8 10 71 67 46 41 36 25 35 32 17 13 11 10 8 9 10 9 11 14 18 161 74 43 28 19 13 10 9 8 8 .66 1.1 25 13 7.1 4.5 3.9 2.5 6.0 4.1 1.7 1.2 .99 .93 .76 .75 .82 .77 .92 1.4 3.2 57 11 4.2 2.2 1.4 .93 .64 .54 .51 .58 FEBRUARY 26 35 27 27 24 52 45 26 25 24 25 22 21 21 20 20 20 19 19 19 19 19 18 18 18 19 19 18 ___ ___ —— 9 15 17 17 17 110 41 27 23 20 32 29 24 16 9 7 6 7 8 7 5 5 5 5 8 14 13 9 ___ .65 1.8 1.3 1.3 1.1 68 6.0 1.9 1.6 1.3 2.2 1.7 1.4 .88 .51 .38 .33 .35 .40 .34 .27 .26 .24 .25 .39 .71 .66 .47 ___ ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 18 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 16 16 16 19 16 15 15 15 14 15 15 20 21 21 24 8 6 6 6 6 6 6 7 9 13 11 9 11 15 14 12 12 12 9 9 8 7 6 6 7 8 8 12 12 12 15 .37 .31 .29 .30 .28 .29 .30 .34 .43 .57 .51 .40 .48 .69 .64 .50 .52 .53 .41 .48 .34 .27 .23 .25 .27 .32 .31 .68 .67 .66 1.0 TOTAL 1231 160.30 665 96.69 536 13.64 410 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR— Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 29 17 16 15 13 13 13 13 12 12 12 12 12 12 11 11 11 11 11 11 12 14 19 14 12 12 14 12 11 11 —— APRIL 19 10 13 20 23 26 19 11 7 6 5 5 6 7 6 5 6 9 6 4 8 9 9 9 11 11 8 5 6 10 MAY 1.6 .49 .55 .78 .83 .94 .70 .40 .22 .18 .17 .17 .18 .22 .19 .14 .18 .29 .18 .12 .25 .34 .50 .32 .36 .38 .29 .16 .19 .30 11 14 20 14 11 14 11 9.7 10 13 9.6 9.4 8.8 8.4 8.3 8.7 9.0 9.2 9.5 9.4 10 15 18 34 43 45 25 17 12 11 10 16 11 12 9 8 15 15 15 7 7 7 9 8 6 7 9 9 9 10 10 8 11 10 24 37 78 72 38 22 13 10 .47 .48 .69 .35 .24 .56 .44 .39 .21 .27 .17 .23 .19 .15 .16 .20 .22 .23 .26 .27 .22 .49 .51 2.3 5.2 13 5.1 1.8 .72 .36 .28 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 10 9.3 9.1 9.1 8.8 8.5 8.6 8.8 8.9 8.7 8.9 9.1 9.1 10 10 11 12 19 73 32 37 83 38 21 127 72 38 26 30 29 9 9 9 8 8 9 11 10 10 9 11 13 11 8 7 6 7 11 181 21 40 320 109 109 589 101 83 25 20 22 .25 .22 .21 .20 .19 .21 .24 .25 .23 .22 .26 .32 .26 .20 .18 .18 .27 .58 97 2.1 13 335 12 7.6 903 22 8.9 1.8 1.7 1.8 TOTAL 398 11.62 458.0 36.16 784.9 1410.37 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR-- Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 411 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 25 19 17 15 20 35 33 136 53 27 20 18 23 19 17 16 14 39 31 28 23 21 20 16 32 29 18 16 15 15 17 827 14124.9 JULY 20 12 7 8 10 21 11 429 35 11 9 10 12 8 5 6 7 51 22 15 8 7 7 7 18 24 16 14 12 11 9 —— 1.4 .60 .34 .32 .60 2.1 1.1 712 6.0 .83 .51 .50 .80 .43 .24 .27 .27 12 2.0 1.1 .51 .40 .37 .31 3.0 2.0 .79 .61 .50 .42 .43 752.75 9881.30 16 18 50 47 25 19 17 24 39 71 101 65 122 112 127 90 59 66 60 49 41 37 47 53 40 33 30 32 131 82 65 1768 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 16 18 50 47 25 19 17 24 39 71 101 65 122 112 127 90 59 66 60 49 41 37 47 53 40 33 30 32 131 82 65 9 50 111 61 18 8 8 15 52 105 180 40 320 101 302 78 38 68 39 27 36 30 54 113 48 24 20 19 435 101 40 .39 3.9 55 8.8 1.2 .40 .38 2.2 6.6 39 105 7.5 229 32 246 23 6.4 19 6.5 3.8 3.9 3.0 12 16 5.3 2.2 1.6 1.7 767 25 7.4 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 58 56 58 49 39 37 33 30 35 28 26 32 29 41 31 24 22 22 22 24 36 47 44 79 46 31 27 26 258 163 50 49 38 26 20 14 10 10 12 7 5 12 13 26 15 9 9 8 7 8 17 39 48 88 22 13 14 14 286 222 14 7.4 7.0 3.5 2.2 1.5 .88 .82 1.2 .51 .38 1.2 1.1 3.2 1.3 .58 .53 .48 .43 .51 1.8 7.3 12 30 2.9 1.1 1.0 1.0 1950 225 1641.17 1453 2280.82 412 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE AUO 1997 11... TIME 1810 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SOS- PENPEP (T/DAY) (80155) SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 318 1200 1030 47 57 65 DATE AUO 1997 11... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 78 SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) 86 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 94 SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 98 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 100 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 22... DEC 23... JAN 1997 09... JUN 19... JUL 18... DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDBP (T/DAY) (80155) SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 1253 1410 1749 1440 1449 62 34 42 61 22 103 759 105 147 88 17 70 12 24 5.2 94 37 96 98 91 RIO GUANAJXBO BASIN 50138000 RIO GUANAJIBO NEAR HORMIGUEROS, PR 413 LOCATION.--Lat 18°08'36", long 67°08'57", Hydrologic Unit 21010003, at bridge on Highway 100, 1.4 mi (2.3 km) west of Hormigueros, and 2.0 mi (3.2 km) downstream from Rio Rosario. DRAINAGE AREA. —120 mi 2 (311 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—Annual low-flow measurements 1959, monthly measurements April 1959 to November 1967, January 1973 to current year. GAGE.—Hater-stage recorder. Datum of gage is at mean sea level. Previous to Nov. 7, 1980, at site 0.3 mi (0.5 km) upstream at datum 7.36 ft (2.243 m) higher. REMARKS.—Records fair. Gage-height and precipitation satellite telemetry at station. Daily discharges affected by sewage treatment plant about 2.1 mi (3.4 km) upstream from gage. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO S DAY OCT NOV 1 228 479 2 348 365 3 520 224 4 386 227 5 235 327 6 180 263 7 144 229 8 118 549 9 106 910 10 94 733 11 90 467 12 85 641 13 79 1060 14 91 640 15 96 442 16 73 370 17 63 463 18 63 673 19 60 473 20 76 411 21 193 467 22 260 559 23 308 449 24 191 360 25 171 311 26 90 249 27 244 216 28 702 188 29 537 160 30 499 140 31 599 TOTAL 6929 13045 MEAN 224 435 MAX 702 1060 MIN 60 140 AC-FT 13740 25870 CFSM 1.86 3.62 IN. 2.15 4.04 STATISTICS OF MONTHLY MEAN MEAN 461 409 MAX 1254 1518 (WY) 1986 1978 MIN 97.5 42.7 (WY) 1992 1992 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 127 116 111 108 106 102 102 101 99 96 99 94 90 86 83 81 76 74 70 67 65 65 61 62 66 78 66 67 70 67 108 2663 85.9 127 61 5280 .72 .83 DATA 127 422 1976 15.4 1992 JAN 118 117 312 202 250 142 181 142 147 135 105 90 80 138 82 75 68 64 60 61 58 145 109 86 76 74 77 70 69 65 65 3463 112 312 58 6870 .93 1.07 FOR WATER 60.8 112 1997 13.8 1973 DAILY FEB 64 77 77 89 176 123 154 88 74 65 61 54 52 49 47 44 43 42 41 40 39 40 39 36 35 36 36 35 —— —— 1756 62.7 176 35 3480 .52 .54 YEARS 1973 51.4 119 1996 13.9 1977 EPT1EMMW 1997 MEAN VALUES MAR 34 33 32 33 32 33 33 32 33 32 30 30 30 30 29 28 28 30 29 29 26 23 22 21 20 20 27 51 75 100 59 1064 34.3 100 20 2110 .29 .33 - 1997 46.5 244 1989 10.6 1977 FOR 1996 CALENDAR YEAR 56761 155 1260 27 28 112600 1. 17. 373 90 40 May 20 Mar 29 Mar 24 29 60 APR 93 44 40 36 34 29 26 25 24 24 23 23 23 21 20 20 19 18 18 18 26 32 31 27 21 18 23 24 19 16 —— 815 27.2 93 16 1620 .23 .25 MAY 14 16 91 35 23 23 22 20 23 24 19 18 16 15 14 14 14 14 14 14 15 17 27 37 54 50 54 27 20 18 17 779 25.1 91 14 1550 .21 .24 JUN 25 17 14 14 13 12 12 12 12 11 11 11 11 11 11 10 11 68 122 110 59 103 131 44 83 149 70 39 39 37 —— 1272 42.4 149 10 2520 .35 .39 JUL 48 31 26 22 21 21 30 138 152 50 34 29 35 27 24 23 23 31 58 75 43 37 31 25 23 53 26 22 19 26 61 1264 40.8 152 19 2510 .34 .39 AUG 40 48 92 137 68 44 34 46 71 99 181 129 472 582 437 265 126 104 139 93 80 67 65 98 91 63 53 47 95 194 208 4268 138 582 34 8470 1.15 1.32 SEP 95 111 132 191 92 77 62 55 61 51 45 45 51 51 56 41 37 36 34 33 41 51 57 95 71 47 41 39 168 390 —— 2356 78.5 390 33 4670 .65 .73 , BY WATER YEAR (WY) 69.6 316 1989 16.1 1977 FOR 1997 39674 109 1060 10 11 1700 18 78690 12 261 61 19 168 636 1980 12.7 1977 WATER YEAR Nov 13 Jun 16 Jun 10 Nov 9 .90 Nov 9 .91 .30 105 504 1979 9.23 1977 98.5 240 1984 26.4 1976 WATER 190 402 69 35000 5 5 128000 28 4 138000 1 21 414 76 21 217 757 1988 42.3 1976 YEARS 1973 - .6 Sep 16 .0 Jun 18 .5 Jun 17 Sep 16 .50 Sep 16 .6 Jun 22 .59 .56 448 2075 1975 78.5 1997 1997 1979 1994 1975 1977 1977 1975 1975 1977 414 RIO GUANAJIBO BASIN 50138000 RIO GUANAJIBO NEAR HORMIGUEROS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—water years 1958 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MAY 30 AU6 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. ATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 0740 608 314 7.1 23.5 60 5.8 67 18 K6500 7700 .997 0835 32 450 7.0 22.5 72 6.7 77 <10 300 400 0945 17 474 6.9 27.0 14 6.5 82 <10 290 K1600 0820 91 400 6.9 26.0 10 5.7 70 12 480 4100 ALKA- NOV 14 MAR 06 MAY 30 AUG 20 NOV 14 MAR 06 MAY 30 AUG 20 NOV 14 MAR 06 MAY 30 AUG 20 K « HARD- NESS TOTAL (MG/L DATE AS CAC03) (00900) 1996 130 1997 ... 210 170 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 <0.10 1997 ... 0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL DATE (MG/L AS N) (00625) 1996 0.60 1997 0.37 0.24 0.43 non-ideal count CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 19 -- 30 26 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 27 — 19 31 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.3 1.3 0.71 1.4 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 20 _- 32 25 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 175 __ 255 242 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.9 5.6 3.1 6.3 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 6.8 _- 16 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 287 — 11.7 59.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.260 0.290 0.280 0.260 SODIUM AD- SORP- TION RATIO (00931) 0.3 — 0.5 0.5 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 88 28 21 7 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.7 — 2.4 2.9 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.720 0.880 0.460 0.960 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- <100 — LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 130 260 220 180 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 <0.010 <0.010 0.020 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- 70 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.740 0.890 0.470 0.980 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 12 — 18 19 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.030 0.030 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 22 — 2 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 9.2 — 18 16 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.56 0.35 0.21 0.39 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 -- RIO GUANAJIBO BASIN 50138000 RIO GUANAJIBO NEAR HORMIGUEROS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MANGA- 475 METHY- DATE NOV 1996 14... MAR 1997 06... MAY 30... AOG 20... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (M6/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 3600 330 180 61 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 <0.01 0.03 PESTICIDE ANALYSES DATE MAY 1997 30... TIME 0945 PCB, TOTAL (00/L) (39516) ALDRIN, TOTAL (OG/L) (39330) CHLOR- DANE, TECH- NICAL TOTAL (OG/L) (39350) P,P'- DDD UNFILT RECOVER (UG/L) (39360) P,P'- DDE, TOTAL (UG/L) (39365) P,P'- DDT UN7ILT RECOVER (OG/L) (39370) DI- AZINON, TOTAL (OG/L) (39570) DI- ELDRIN TOTAL (UO/L) (39380) ENDO- SULFAN, I TOTAL (OG/L) (39388) <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN HATER UNFLTRD ETHION, DATE REC TOTAL (OG/L) (OG/L) MAY 1997 30... HEPTA- HEPTA- CBLOR MALA- CBLOR, EPOXIDE LINDAME THION, TOTAL TOTAL TOTAL TOTAL (OG/L) (OG/L) (OG/L) (UO/L) (39390) (39398) (39410) (39420) (39340) (39530) METH- OXY- CHLOR, TOTAL (UO/L) (39480) METHYL PARA- THION, TOTAL (UO/L) MZREX, TOTAL (UO/L) (39600) (39755) •cO.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE MAY 1997 30... PARA- PCNS THION, UNFXLT TOTAL RECOVER (UO/L) (39540) PER- THANE TOTAL (UO/L) (UO/L) (39250) (39034) TOX- APHENB, TOTAL (UO/L) (39400) <0.010 <0.100 <0.100 <1.00 TOTAL TRI- THION (UO/L) (39786) <0.010 2,4-D, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL TOTAL TOTAL (UO/L) (UO/L) (UO/L) (UO/L) (39730) (39740) (82183) (39760) 0.010 <0.010 <0.010 <0.010 416 THIS PAGE WAS LEFT BLANK INTENTIONALLY o>-- .-'•y ->> 1440 Rio Cul*t)r-,no» basin^ •*" ~"">«^_~'" —^ w#/'0 <?/•<! £««*• L .«>! MAYA V—^v--^ V '-W* — -»» CMMM kMi» ^/ ?C «.'» Cn ••!»>*• »fc NV^^^————^>———^f~^' / ^. ^*"v ^N^.X^ /—-^-/ : MARtCAO^ S / fa& Drainoo* boundory-y / / J ^**r it /<^-<~'- (^../^-^ \ EXPLANATION \ 1440 SURFACE-WATER STATION AND NUMBER 1388 QUAUTY-OF-WATER STATION AND NUMBER 1415 LAKE-ELEVATION STATION AND NUMBER LARES «i"o rename'fee»i* 1415 ^ :.~r-\ yv i'o faaco Map area- 0123456 KILOMETERS I S " 'T^ i1 ""H 01234 MILES Figure 25.--Rio Yaguez and Rio Grande de Anasco basins. d1 ft ^ ' ° RIO YAGUEZ BASIN 50138800 RIO YAGUEZ NEAR MAYAGUEZ, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°12'31", long 67°07'07", at steel-truss bridge on unnumbered paved road about 800 ft (244 m) south of Highway 106, 1.8 mi (2.9 km) west of Highways 106 and 352 junction, and 1.4 mi (2.3 km) east-northeast from Mayaguez plaza. DRAINAGE AREA.—6.7 mi 2 (17.3 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 TIME DIS- CHARGE, INST. CUBIC FEET PER SECOND SPE- CIFIC CON- DUCT- ANCE (US/CM) PH WATER WHOLE FIELD (STAND- ARD UMITS) TEMPER- ATURE WATER (DEG C) TUR- BID- ITY (NTU) OXYGEN, DIS- SOLVED (MG/L) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) STREP- TOCOCCI FECAL, (COLS. PER 100 ML) NOV 1996 12... MAR 1997 05... MAY 29... AU6 19... 1430 1435 1145 1445 (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 37 4.6 1.6 7.6 210 310 304 270 6.6 7.1 7.0 7.0 25.0 23.5 25.5 27.0 180 0.70 0.60 5.7 8.0 8.9 7.6 7.8 96 105 93 98 230000 1800 270 580 250000 3400 880 600 NOV 1996 12... MAR 1997 05... MAY 29... …