Diaz et al 1999 Water resources data Puerto Rico and the U.S. Virgin Islands water year 1999

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Date: 1999
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Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1999 U.S. Department of the Interior U.S. Geological Survey Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands, and with other agencies Isla de Vieques Isla de Culebra St. Thomas St. Croix P U E R T O R I C O U.S. VIRGIN ISLANDS St. John CALENDAR FOR WATER YEAR 1999 1998 JANUARY NOVEMBER DECEMBER S M T W T F S S M T W T F S S M T W T F S 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 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 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 1999 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 OCTOBER FEBRUARY MARCH 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 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 S M T W T F S S M T W T F S S M T W T F S APRIL MAY JUNE S M T W T F S S M T W T F S S M T W T F S 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 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 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 JULY AUGUST SEPTEMBER S M T W T F S S M T W T F S S M T W T F S 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 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 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 U.S. Department of the Interior U.S. Geological Survey Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1999 By Pedro L. Díaz, Zaida Aquino, Carlos Figueroa-Alamo, Ricardo J. Vachier, and Ana V. Sánchez Water-Data Report PR-99-1 Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands, and with other agencies U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, 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 2000 III 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 the U.S. Geological Survey policy and established guidelines, the following personnel contributed significantly to the collection, processing and tabulations of the data: José M. Agis Rafael Peña-Cortez George Arroyo Ronald T. Richards Gregory Cherry Carlos C. Rodríguez Iris M. Concepción Julio A. Rodríguez Israel Cruz Miguel Rodríguez Angel G. Ferrer Rafael M. Rodríguez Robert Fitzhugh José René Sánchez Wilfredo García Luis Santiago-Rivera Hector Guardiola Carlos Santos Evelyn S. Guevara Luis Soler Senén Guzmán-Ríos Angel Torres Felipe Hernández James Torres Sandra Lagares José A. Torres José Merced Ahmed Valencia Carlos Narvaez Luis Vega Victoria Nuñez Francisco Maldonado prepared the illustrations and Evelyn S. Guevara typed the text of the report and was mainly responsible for the assemble of the book using Automated Annual Report (AAR) Scripts for Surface Water Discharge and Water Quality Stations. 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. Rodríguez, District Chief, Caribbean District, San Juan, Puerto Rico. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std 239-18 298-102 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS 6. AUTHOR(S) 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. AGENCY REPORT NUMBER 11. SUPPLEMENTARY NOTES 12a. DISTRIBUTION / AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE 13. ABSTRACT (Maximum 200 words) 14. SUBJECT TERMS 15. NUMBER OF PAGES 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT 18. SECURITY CLASSIFICATION OF THIS PAGE 19. SECURITY CLASSIFICATION OF ABSTRACT 20. LIMITATION OF ABSTRACT 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED SPONSORING / MONITORING Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503. July 10, 2000 Annual - October 1, 1998 to September 30, 1999 Water Resources Data for Puerto Rico and the U.S. Virgin Islands Water Year 1999 Pedro L. Díaz, Zaida Aquino, Carlos Figueroa-Alamo, Ricardo J. Vachier, Ana V. Sánchez U.S. Geological Survey, Water Resources Division GSA Center, 651 Federal Drive, Suite 400-15 Guaynabo, Puerto Rico 00965 USGS-WDR-PR-99-1 U.S. Geological Survey, Water Resources Division GSA Center, 651 Federal Drive, Suite 400-15 Guaynabo, Puerto Rico 00965 USGS-WDR-PR-99-1 Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands, and other agencies. NO RESTRICTION ON DISTRIBUTIONS Water resources data for surface-water, quality-of-water, and ground-water records for the 1999 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 76 streamflow-gaging stations; daily sediment records for 25 streamflow stations; stage records for 18 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 107 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. *Surface water, *Water quality, *Ground water, Aquifers, Chemical analysis, Gaging stations, Hydrologic data sediments, Streamflow, Water analysis, Water levels, Lakes 616 Unclassified Unclassified V CONTENTS Page Preface........................................................................................................................................................................................ iii 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 ....................................................................................... xiv Introduction..................................................................................................................................................................................1 Cooperation..................................................................................................................................................................................2 Summary of hydrologic conditions..............................................................................................................................................3 Rainfall ..................................................................................................................................................................................3 Surface water.........................................................................................................................................................................3 Ground water.........................................................................................................................................................................5 Water quality .........................................................................................................................................................................9 Special networks and programs .................................................................................................................................................10 Explanation of records...............................................................................................................................................................10 Station identification numbers.............................................................................................................................................11 Downstream order system.............................................................................................................................................11 Latitude-longitude system.............................................................................................................................................11 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................................................................................................................................................24 Arrangement of records ................................................................................................................................................24 On-site measurements and sample collection ...............................................................................................................24 Water temperature......................................................................................................................................................................25 Sediment........................................................................................................................................................................25 Laboratory measurements.............................................................................................................................................25 Data presentation...........................................................................................................................................................26 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...............................................................................................42 Surface- and quality-of-water records for Puerto Rico..............................................................................................................47 Water-quality at partial-record stations in Puerto Rico and U.S. Virgin Islands.....................................................................439 Ground-water records for Puerto Rico.....................................................................................................................................467 Surface-water records for U.S. Virgin Islands.........................................................................................................................575 Ground-water records for U.S. Virgin Islands ........................................................................................................................585 Index ........................................................................................................................................................................................593 VI ILLUSTRATIONS Page Figure 1. Graphs showing monthly-mean discharge of selected streams in Puerto Rico .......................................................4 2. Graphs showing ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands.......................8 3. Map showing location of maximum concentration of fecal coliform bacteria at the water-quality sampling sites in Puerto Rico ......................................................................................................12 4. Map showing location of maximum concentration of fecal streptococci bacteria at the water-quality sampling sites in Puerto Rico ......................................................................................................13 5. Map showing location of surface-water stations in Puerto Rico ...........................................................................14 6. Map showing location of water-quality stations in Puerto Rico............................................................................15 7. Map showing location of ground-water stations in Puerto Rico............................................................................16 8. Map showing location of surface-water stations in the U.S. Virgin Islands..........................................................17 9. Map showing location of ground-water stations in the U.S. Virgin Islands..........................................................18 10. Grid showing system for numbering wells and miscellaneous sites (latitude and longitude)..............................19 11. Map showing the Río Guajataca basin..................................................................................................................49 12. Map showing the Río Camuy basin......................................................................................................................59 13. Map showing the Río Grande de Arecibo basin ...................................................................................................63 14. Map showing the Río Grande de Manatí basin.....................................................................................................99 15. Map showing the Río Cibuco basin....................................................................................................................123 16. Map showing the Río de la Plata basin...............................................................................................................133 17. Map showing the Río Hondo to Río Puerto Nuevo basins.................................................................................157 18. Map showing the Río Grande de Loíza basin.....................................................................................................197 19. Map showing northeastern river basins -- Río Herrera to Río Antón Ruíz basins .............................................293 20. Map showing southeastern river basins -- Río Humacao to Quebrada Aguas Verdes .......................................331 21. Map showing south coast river basins -- Río Salinas to Río Jacaguas basins ....................................................347 22. Map showing south coast river basins -- Río Inabón to Río Loco basins...........................................................367 23. Map showing the Río Guanajibo basin...............................................................................................................399 24. Map showing the Río Yagüez and Río Grande de Añasco basins......................................................................415 25. Map showing the Río Culebrinas basin ..............................................................................................................427 TABLES Page Table 1. Island-wide monthly rainfall for the water year 1999 and annual averages for the 30-year reference period, 1961-90........................................................................................................................3 2. Highest ground-water level recorded during water year 1999 and previous highest ground-water levels at selected wells in Puerto Rico ...........................................................................................6 3. Lowest ground-water levels recorded during water year 1999 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 1999 .....................................................................................................................9 VII SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, 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 Río Guajataca at Lares (d,c,b)....................................................................................................... 50010500 50 Lago Guajataca at Damsite near Quebradillas (e) ........................................................................ 50010800 54 Canal Principal de Diversiones at Lago Guajataca (c,b) .............................................................. 50011000 55 Río Guajataca above mouth near Quebradillas (c,b) .................................................................... 50011400 57 RIO CAMUY BASIN Río Camuy near Bayaney (d)........................................................................................................ 50014800 60 RIO GRANDE DE ARECIBO BASIN Lago Garzas near Adjuntas (e) ............................................................................................. 50020100 64 Río Grande de Arecibo near Adjuntas (c,b).................................................................................. 50020500 65 Río Grande de Arecibo near Utuado (c,b) .................................................................................... 50025000 67 Río Caonillas at Paso Palma (d,s)................................................................................................. 50026025 69 Río Caonillas above Lago Caonillas near Jayuya (c,b) ................................................................ 50026050 75 Lago Caonillas at Damsite near Utuado (e).......................................................................... 50026140 77 Lago Dos Bocas at Damsite near Utuado (e)........................................................................ 50027100 78 Río Grande de Arecibo below Lago Dos Bocas near Florida (c,b) .............................................. 50027250 79 Río Grande de Arecibo above Arecibo (d,s)................................................................................. 50027750 81 Río Tanamá near Utuado (d,c,b,s) ........................................................................................ 50028000 86 Río Tanamá at Charco Hondo (d) ........................................................................................ 50028400 93 Río Grande de Arecibo at Central Cambalache (d,c,b) ................................................................ 50029000 95 RIO GRANDE DE MANATI BASIN Río Orocovis at Orocovis (d)................................................................................................ 50030460 100 Río Orocovis near Orocovis (c,b)......................................................................................... 50030700 102 Río Grande de Manatí near Morovis (d,c,b)................................................................................. 50031200 104 Lago El Guineo at Damsite near Villalba (e)........................................................................ 50032290 108 Lago de Matrullas at Damsite near Orocovis (e).................................................................. 50032590 109 Río Bauta near Orocovis (d) ................................................................................................. 50034000 110 Río Grande de Manatí at Ciales (d) .............................................................................................. 50035000 112 Río Grande de Manatí at Highway 149 at Ciales (c,b)................................................................. 50035500 114 Río Cialitos at Highway 649 at Ciales (c,b) ......................................................................... 50035950 116 Río Grande de Manatí at Highway 2 near Manatí (d,c,b,p).......................................................... 50038100 118 LAGUNA TORTUGUERO BASIN Laguna Tortuguero Outlet near Vega Baja (c,b) .......................................................................... 50038200 122 RIO CIBUCO BASIN Río Cibuco below Corozal (d,c,b) ................................................................................................ 50038320 124 Río Cibuco at Vega Baja (d,c,b)................................................................................................... 50039500 128 RIO DE LA PLATA BASIN Lago Carite at Gate Tower near Cayey (e)................................................................................... 50039990 134 Río de la Plata at Proyecto La Plata (c,b) ..................................................................................... 50043000 135 Río de la Plata at Comerio (d,s).................................................................................................... 50043800 137 Río de la Plata near Comerio (c,b)................................................................................................ 50044000 143 Río Guadiana near Naranjito (c,b)........................................................................................ 50044850 145 Lago La Plata at Damsite near Toa Alta (e) ................................................................................. 50045000 147 Río de la Plata below La Plata Dam (d,s)..................................................................................... 50045010 148 Río de la Plata at Highway 2 near Toa Alta (d,c,b,s,p)................................................................. 50046000 153 RIO HONDO BASIN Río Hondo at Flood Channel near Cataño (c,b)............................................................................ 50047530 158 VIII 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 Río de Bayamón at Arenas (d)...................................................................................................... 50047535 160 Río Sabana at Vista Monte (d).............................................................................................. 50047540 162 Lago de Cidra at Damsite near Cidra (e) ...................................................................................... 50047550 164 Río de Bayamón below Cidra Dam (d,s)...................................................................................... 50047560 165 Río de Bayamón near Aguas Buenas (c,b) ................................................................................... 50047600 171 Río de Bayamón near Bayamón (d).............................................................................................. 50047850 173 Río Guaynabo near Bayamón (c,b)....................................................................................... 50047990 175 Río de Bayamón at Flood Channel at Bayamón (c,b,p) ............................................................... 50048510 177 RIO PUERTO NUEVO BASIN Río Piedras: Lago Las Curías at Damsite near Río Piedras (e)......................................................................... 50048680 179 Quebrada Las Curías below Las Curías Damsite (d).................................................................... 50048690 180 Río Piedras at El Señorial(d,s)...................................................................................................... 50048770 186 Río Piedras near Río Piedras (c,b,p)............................................................................................. 50048800 188 Río Piedras at Hato Rey (d,c,b) .................................................................................................... 50049100 190 Laguna San José: Laguna San José No. 2 at San Juan (c,b)...................................................................................... 50049820 194 Bahía de San Juan: Bahía de San Juan No. 5 at San Juan (c,b).................................................................................... 50049920 195 QUEBRADA BLASINA BASIN Quebrada Blasina near Carolina (c,b)........................................................................................... 50050300 198 RIO GRANDE DE LOIZA BASIN Río Grande de Loíza at Quebrada Arenas (d)............................................................................... 50050900 200 Quebrada Blanca at El Jagual (d,s)....................................................................................... 50051150 202 Quebrada Salvatierra near San Lorenzo (d,s) ....................................................................... 50051180 208 Río Cayaguás at Cerro Gordo (d) ......................................................................................... 50051310 214 Río Grande de Loíza at Highway 183 near San Lorenzo (d,s)..................................................... 50051800 216 Río Turabo above Borinquen (d,s)........................................................................................ 50053025 222 Río Grande de Loíza at Caguas (d,c,b,s) ...................................................................................... 50055000 228 Río Caguitas near Aguas Buenas (d,s).................................................................................. 50055100 235 Río Caguitas at Villa Blanca at Caguas (d,s)........................................................................ 50055225 241 Río Caguitas at Highway 30 at Caguas (c,b)........................................................................ 50055250 247 Río Bairoa at Bairoa (d,s) ..................................................................................................... 50055390 249 Río Bairoa near Caguas (c,b)................................................................................................ 50055400 255 Río Gurabo: Río Gurabo below El Mangó (d,s)........................................................................................ 50055750 257 Río Valenciano near Juncos (d,s)..................................................................................... 50056400 262 Río Gurabo at Gurabo (d,s)................................................................................................... 50057000 268 Río Gurabo near Gurabo (c,b) .............................................................................................. 50057025 274 Río Cañas at Río Cañas (d,s) ................................................................................................ 50058350 276 Lago Loíza at Damsite near Trujillo Alto (c,b,e).......................................................................... 50059000 282 Río Grande de Loíza below Damsite (d,s).................................................................................... 50059050 284 Río Grande de Loíza below Trujillo Alto (c,b)............................................................................. 50059100 289 Río Canóvanas near Campo Rico (d).................................................................................... 50061800 291 RIO ESPIRITU SANTO BASIN Quebrada Sonadora near El Verde........................................................................................ 50063440 294 Río Espíritu Santo near Río Grande (d,c,b).................................................................................. 50063800 296 Río Grande near El Verde (d)............................................................................................... 50064200 300 RIO MAMEYES BASIN Río Mameyes near Sabana (d,s).................................................................................................... 50065500 302 Río Mameyes at Mameyes (d)...................................................................................................... 50066000 308 IX SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME--Continued Station number Page RIO SABANA BASIN Río Sabana at Sabana (d).............................................................................................................. 50067000 310 RIO FAJARDO BASIN Río Fajardo above Fajardo (d,s).................................................................................................... 50070500 312 Río Fajardo near Fajardo (d,c,b,p,s) ............................................................................................. 50071000 318 Río Fajardo below Fajardo (c,b)................................................................................................... 50072500 324 RIO BLANCO BASIN Quebrada Guabá near Naguabo (d)............................................................................................... 50074950 326 Río Icacos near Naguabo (d)......................................................................................................... 50075000 328 RIO HUMACAO BASIN Río Humacao at Las Piedras (d) ................................................................................................... 50081000 332 Río Humacao at Highway 3 at Humacao (c,b) ............................................................................. 50082000 334 RIO GUAYANES BASIN Río Guayanés at Yabucoa (c,b,p) ................................................................................................. 50083500 335 Río Guayanés above mouth at Playa de Guayanés (c,b) .............................................................. 50086500 337 RIO MAUNABO BASIN Río Maunabo at Lizas (d) ............................................................................................................. 50090500 338 Río Maunabo at Maunabo (c,b) .................................................................................................... 50091000 340 RIO CHICO BASIN Río Chico at Providencia (c,b)...................................................................................................... 50091800 341 RIO GRANDE DE PATILLAS BASIN Río Grande de Patillas near Patillas (d,c,b) .................................................................................. 50092000 343 Lago Patillas at Damsite near Patillas (e) ..................................................................................... 50093045 346 RIO SALINAS BASIN Río Lapas near Rabo del Buey (d)................................................................................................ 50100200 348 Río Majada at La Plena (d)........................................................................................................... 50100450 350 RIO COAMO BASIN Río Coamo at Coamo (d).............................................................................................................. 50106100 352 Río Coamo near Coamo (c,b) ....................................................................................................... 50106500 354 RIO DESCALABRADO BASIN Río Descalabrado near Los Llanos (d).......................................................................................... 50108000 356 RIO JACAGUAS BASIN Río Toa Vaca above Lago Toa Vaca (d,s)............................................................................ 50110900 358 Lago Toa Vaca at Damsite near Villaba (e).................................................................................. 50111210 363 Lago Guayabal at Damsite near Juana Díaz (e)............................................................................ 50111300 364 Río Jacaguas at Juana Díaz (d) ..................................................................................................... 50111500 365 IO INABON BASIN Río Inabón at Real Abajo (d)........................................................................................................ 50112500 368 RIO BUCANA BASIN Río Bucaná: Río Cerrillos above Lago Cerrillos near Ponce (d)....................................................................... 50113800 370 Lago Cerrillos at Damsite near Ponce (e)..................................................................................... 50113950 372 Río Cerrillos near Ponce (d,c,b).................................................................................................... 50114000 373 Río Bucaná at Highway 14 Bridge near Ponce (d)....................................................................... 50114390 377 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 Río Portugués at Tibes (d,s).......................................................................................................... 50114900 379 Río Portugués near Ponce (c,b)................................................................................................... ..50115000 385 Río Potugués at Highway 14 near Ponce (d) ................................................................................ 50115900 387 Río Portugués at Ponce (c,b,p)...................................................................................................... 50116200 389 RIO GUAYANILLA BASIN Río Guayanilla near Guayanilla (d).............................................................................................. 50124200 391 Río Guayanilla at Central Rufina (c,b,p) ...................................................................................... 50124700 393 RIO YAUCO BASIN Lago Lucchetti at Damsite near Yauco (e) ................................................................................... 50125780 395 RIO LOCO BASIN Lago Loco at Damsite near Yauco (e).......................................................................................... 50128900 396 Río Loco at Guánica (c,b,p).......................................................................................................... 50129700 397 RIO GUANAJIBO BASIN Río Guanajibo at Highway 119 at San Germán (d)...................................................................... 50131990 400 Río Guanajibo near San Germán (c,b).......................................................................................... 50133600 402 Río Rosario near Hormigueros (d,c,b,s) ............................................................................... 50136400 404 Río Guanajibo near Hormigueros (d,c,b,p)................................................................................... 50138000 411 RIO YAGUEZ BASIN Río Yagüez near Mayagüez (c,b).................................................................................................. 50138800 416 RIO GRANDE DE AÑASCO BASIN Lago Guayo at Damsite near Castañer (e)............................................................................ 50141500 418 Río Grande de Añasco near Lares (c,b)........................................................................................ 50143000 419 Río Grande de Añasco near San Sebastián (d,c,b)........................................................................ 50144000 421 Río Grande de Añasco near Añasco (c,b,p).................................................................................. 50146000 425 RIO CULEBRINAS BASIN Río Culebrinas near San Sebastián (c,b)....................................................................................... 50147600 428 Río Culebrinas at Highway 404 near Moca (d) ............................................................................ 50147800 430 Río Culebrinas at Margarita Dam near Aguada (d)...................................................................... 50148890 432 Río Culebrinas near Aguada (c,b,p).............................................................................................. 50149100 436 Analyses of samples collected of water-quality partial-record stations and miscellaneous sites.................................................................................................................... 440 ST. THOMAS, U.S. VIRGIN ISLANDS Bonne Resolution Gut at Bonne Resolution (d) ........................................................................... 50252000 576 Turpentine Run at Mount Zion (d)................................................................................................ 50274000 578 ST. JOHN, U.S. VIRGIN ISLANDS Guinea Gut at Bethany (d)............................................................................................................ 50295000 580 ST. CROIX, U.S. VIRGIN ISLANDS Jolly Hill Gut at Jolly Hill (d)....................................................................................................... 50345000 582 XI GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED Page RIO GUAJATACA BASIN Well 182925067031100 Local number 1001 .......................................................................................................................................468 Well 182422067015100 Local number 165 ........................................................................................................................................469 Well 182647066552400 Local number 202 ........................................................................................................................................470 RIO CAMUY BASIN Well 182723066511200 Local number 1026 .......................................................................................................................................471 Well 182431066463400 Local number 1027 .......................................................................................................................................472 RIO GRANDE DE ARECIBO BASIN Well 182756066454700 Local number 1051 .......................................................................................................................................473 Well 182737066370900 Local number 204 ........................................................................................................................................474 Well 182616066364100 Local number 1052 .......................................................................................................................................475 Well 182626066345100 Local number 1053 .......................................................................................................................................476 Well 182603066333601 Local number 1054 .......................................................................................................................................477 Well 182642066394900 Local number 1055 .......................................................................................................................................478 Well 182639066385200 Local number 1056 .......................................................................................................................................479 Well 182544066341500 Local number 205 ........................................................................................................................................480 Well 182209066340600 Local number 1057 .......................................................................................................................................482 RIO GRANDE DE MANATI BASIN Well 182757066325600 Local number 206 ........................................................................................................................................483 Well 182710066303700 Local number 207 ........................................................................................................................................484 Well 182549066304300 Local number 166 ........................................................................................................................................485 Well 182506066280200 Local number 1076 .......................................................................................................................................486 Well 182308066260400 Local number 210 ........................................................................................................................................487 Well 182548066265700 Local number 1077 .......................................................................................................................................488 RIO CIBUCO BASIN Well 182614066261500 Local number 1101 .......................................................................................................................................489 Well 182712066251700 Local number 1102 .......................................................................................................................................490 Well 182615066235300 Local number 211 ........................................................................................................................................491 Well 182647066201700 Local number 70 .........................................................................................................................................492 Well 182515066194000 Local number 212 ........................................................................................................................................493 Well 182330066185700 Local number 213 ........................................................................................................................................494 Well 182426066260400 Local number 1103 .......................................................................................................................................495 RIO DE LA PLATA BASIN Well 182804066173500 Local number 1126 .......................................................................................................................................496 Well 182526066165001 Local number 1127 .......................................................................................................................................497 Well 182548066164401 Local number 1128 .......................................................................................................................................498 Well 182620066163400 Local number 1129 .......................................................................................................................................499 Well 182620066163403 Local number 1130 .......................................................................................................................................500 Well 182657066162700 Local number 1131 .......................................................................................................................................501 Well 182657066162701 Local number 1132 .......................................................................................................................................502 Well 182654066150600 Local number 1133 .......................................................................................................................................503 Well 182530066135400 Local number 216 ........................................................................................................................................504 XII GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED Page RIO DE LA PLATA BASIN--Continued Well 182655066142400 Local number 217 .........................................................................................................................................505 Well 180649066095500 Local number 1134 .......................................................................................................................................506 RIO HONDO TO RIO PUERTO NUEVO BASINS Well 182441066082600 Local number 219 ........................................................................................................................................507 Well 182531066075900 Local number 652 ........................................................................................................................................508 Well 182511066045401 Local number 1152 .......................................................................................................................................509 Well 182435066052700 Local number 1153 .......................................................................................................................................510 Well 182445066043401 Local number 1154 .......................................................................................................................................511 Well 182443066041502 Local number 1155 .......................................................................................................................................512 Well 182417066042700 Local number 1156 .......................................................................................................................................513 Well 182406066034700 Local number 1158 .......................................................................................................................................514 Well 182451066080200 Local number 1159 .......................................................................................................................................515 RIO GRANDE DE LOIZA BASIN Well 181352066025300 Local number 1176 .......................................................................................................................................518 Well 181311066022500 Local number 1177 .......................................................................................................................................519 Well 181446066013400 Local number 1178 .......................................................................................................................................520 Well 181539066014500 Local number 1179 .......................................................................................................................................521 Well 181550065593200 Local number 50 .........................................................................................................................................522 Well 182515065594100 Local number 222 ........................................................................................................................................523 Well 181540065580300 Local number 1180 .......................................................................................................................................524 Well 181513065554600 Local number 1181 .......................................................................................................................................525 RIO HERRERA TO RIO ANTON RUIZ BASINS Well 182344065490801 Local number 1201 .......................................................................................................................................526 Well 182223065455900 Local number 1202 .......................................................................................................................................527 Well 181230065444900 Local number 1203 .......................................................................................................................................528 Well 182138065431800 Local number 1204 .......................................................................................................................................529 Well 182131065421100 Local number 1205 .......................................................................................................................................530 Well 181823065401900 Local number 1206 .......................................................................................................................................531 Well 181917065382701 Local number 1207 .......................................................................................................................................532 Well 182234065440000 Local number 1208 .......................................................................................................................................533 RIO HUMACAO TO QUEBRADA AGUAS VERDES BASINS Well 180358065503600 Local number 1226 .......................................................................................................................................535 Well 180415065513900 Local number 96 .........................................................................................................................................536 Well 175855066050500 Local number 1228 .......................................................................................................................................537 Well 175728066072200 Local number 1229 .......................................................................................................................................538 Well 175719066085500 Local number 1230 .......................................................................................................................................539 Well 175858066100200 Local number 6 ..........................................................................................................................................540 Well 180002066132200 Local number 1231 .......................................................................................................................................541 Well 180001066122002 Local number 1232 .......................................................................................................................................542 Well 175947066130601 Local number 1233 .......................................................................................................................................543 Well 175957066123400 Local number 1234 .......................................................................................................................................544 XIII GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED Page RIO HUMACAO TO QUEBRADA AGUAS VERDES BASINS--Continued Well 180027065541700 Local number 1235 ........................................................................................................................................545 Well 180018066010100 Local number 1236 .......................................................................................................................................546 Well 175903066024100 local number 1237.........................................................................................................................................547 Well 175841066104500 Local number 1238 .......................................................................................................................................548 Well 175814066102200 Local number 1239 .......................................................................................................................................549 RIO SALINAS TO RIO JACAGUAS BASINS Well 175809066133100 Local number 1251 .......................................................................................................................................551 Well 180206066135500 Local number 1252 .......................................................................................................................................552 Well 180104066152300 Local number 1253 .......................................................................................................................................553 Well 175910066155500 Local number 1254 .......................................................................................................................................554 Well 175903066165000 Local number 1256 .......................................................................................................................................555 Well 175943066224800 Local number 1257 ........................................................................................................................................556 Well 175829066232200 Local number 87 .........................................................................................................................................557 Well 180020066261500 Local number 1258 .......................................................................................................................................558 Well 180602066133100 Local number 1260 .......................................................................................................................................559 RIO INABON TO RIO LOCO BASINS Well 175950066354200 Local number 141 ........................................................................................................................................560 Well 175934066364800 Local number 1276 .......................................................................................................................................561 Well 180045066381600 Local number 1277 .......................................................................................................................................562 Well 180156066434000 Local number 1278 .......................................................................................................................................563 Well 180133066503300 Local number 132 ........................................................................................................................................564 Well 175840066494400 Local number 1279 .......................................................................................................................................565 RIO GUANAJIBO BASIN Well 180132067033800 Local number 143 ........................................................................................................................................566 Well 180542067084000 Local number 1301 .......................................................................................................................................567 Well 180628067084300 Local number 1302 .......................................................................................................................................568 Well 180628067084301 Local number 1303 .......................................................................................................................................569 Well 180802067073300 Local number 1304 .......................................................................................................................................570 RIO YAGÜEZ TO RIO GRANDE DE AÑASCO BASINS Well 181232067083700 Local number 1326 .......................................................................................................................................571 RIO CULEBRINAS BASIN Well 182017067143300 Local number 1352 .......................................................................................................................................572 Well 182442067091700 Local number 200 ........................................................................................................................................573 ST. CROIX, U.S. VIRGIN ISLANDS Well 174225064472000 Local number 2 .............................................................................................................................................586 Well 174243064475100 Local number 3 .............................................................................................................................................587 Well 174316064480800 Local number 13 ...........................................................................................................................................588 ST. THOMAS, U.S. VIRGIN ISLANDS Well 182038064550300 Local number 6 .............................................................................................................................................589 Well 182038064580000 Local number 8 .............................................................................................................................................590 ST. JOHN, U.S. VIRGIN ISLANDS Well 181956064464500 Local number 11 ...........................................................................................................................................591 XIV WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 DISCONTINUED STREAMFLOW STATIONS 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 Drainage Period of number area (mi2) record 50007000 Quebrada de los Cedros near Isabela 6.91 1970 50010600 Río Guajataca above Lago de Guajataca -- 1984-89 50011000 Canal Diversion Lago Guajataca -- 1970 50011200 Río Guajataca below Lago Guajataca -- 1969-70,1984-87 50011400 Río Guajataca above mouth near Quebradillas -- 1969-70,1984-89 50013000 Río Camuy near Lares 7.62 1969-71 50014000 Río Criminales near Lares 4.68 1969-70 50014600 Río Camuy at Tres Pueblos Sinkhole -- 1990-96 50015700 Río Camuy near Hatillo -- 1984-96 50016000 Río Camuy near Camuy -- 1969-73 50021050 Río Pellejas below Central Pellejas 7.89 1972-75 50021500 Río Pellejas near Utuado 9.55 1969-71 50023000 Río Viví near Central Pellejas 5.66 1969-75 50027200 Río Grande de Arecibo blw. Lago dos Bocas 169 1970-71 50031500 Río Sana Muerto near Orocovis 3.68 1965-70 50035200 Río Grande de Manatí at Hwy 145 at Ciales 132 1972 50035950 Río Cialitos at Hwy 649 at Ciales 17 1970-82 50038360 Río Mavilla near Corozal 9.51 1969-70 50038600 Río Unibón near Morovis 5.29 1969-70 50038700 Río Morovis at Morovis 1.26 1968 50038900 Río Indio at Vega Baja -- 1963,66,71 50039600 Río Cibuco at Central San Vicente -- 1969-72 50043200 Río Usabon near Barranquitas 9.15 1968-69,71 50043400 Río Aibonito Tributary near Aibonito 1.13 1968-71 50044600 Río Guadiana near Naranjito 1.73 1971 50044650 Quebrada del Toro near Naranjito 0.54 1971 50044800 Quebrada Anones near Naranjito 2.32 1971 50045700 Río Lajas at Toa Alta 8.65 1966-75 50047820 Río de Bayamón at Hwy 174 near Bayamón 31.90 1966 50048000 Río de Bayamón at Bayamón 71.90 1963-67 50049000 Río Piedras at Río Piedras 12.5 1971-82, 1987-93 50049310 Quebrada Josefina at Piñero Avenue 3.84 1988-91 50053050 Río Turabo at Borinquen 7.89 1984-90 50054000 Quebrada de las Quebradillas near Caguas 6.25 1969-71,73 50055170 Río Cagüitas near Caguas 8.27 1992-97 50055650 Quebrada Caimito near Juncos 0.82 1984-87 50056000 Río Valenciano near Las Piedras 6.85 1971 50056900 Quebrada Mamey near Gurabo 2.30 1984-92 50058300 Quebrada Arena near Caguas -- 1971 50061300 Río Canovanillas near Loíza 14.40 1968-73 XV WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 DISCONTINUED STREAMFLOW STATIONS--Continued Station Station name Drainage Period of number area (mi2) record 50062500 Río Herrera near Colonia Dolores 2.75 1968-72 50063300 Río Espíritu Santo near El Verde 2.23 1968-73 50063500 Quebrada Toronja at El Verde 0.064 1983-96 50065700 Río Mameyes at Hwy 191 at Mameyes 11.80 1967-85 50072000 Río Fajardo at Fajardo 21.60 1960-63 50073200 Río Daguao at Daguao 2.26 1966-82 50073400 Quebrada Palma at Daguao 4.84 1972-77 50074000 Río Santiago at Naguabo 4.99 1966-82 50075500 Río Blanco at Florida 11.00 1966-82 50076000 Río Blanco near Florida 12.30 1983-85 50077000 Río Blanco at Río Blanco 17.60 1973-77 50077400 Río Blanco at Colonia La Fe 18.80 1967-70 50078500 Río Anton Ruíz at Central Pasto Viejo 4.33 1968 50081500 Río Humacao near Humacao 9.23 1973 50082000 Río Humacao at Hwy 3 at Humacao 17.30 1983-85 50082200 Río Humacao near La Suiza 19.90 1965-66, 1969-71 50082800 Río Guayanés near Colonia Laura 4.69 1969-82 50083500 Río Guayanés near Yabucoa 17.20 1969-71 50084000 Río Limones near Yabucoa 7.89 1969-71 50085100 Río Guayanés at Central Roig 26.60 1965-66, 1968,70 50086100 Río del Ingenio at Comunas 5.50 1965-66, 1968-69 50086500 Río Guayanés at Playa Guayanés 34.00 1965-66, 1968-71 50087200 Caño Santiago near Central Roig 6.04 1965-71 50091000 Río Maunabo at Maunabo 12.40 1965,67, 1969-82 50091200 Río Maunabo near Maunabo 12.70 1971-72 50091400 Río Jacaboa near Lamboglia 4.13 1965-73 50091700 Río Chico at Patillas 6.82 1965, 1969-72 50091800 Río Chico at Providencia 4.90 1965, 1967-69, 1971 50094200 Río Grande de Patillas at Patillas 27.90 1967, 1969, 1971 50094300 Río Grande de Patillas at Providencia 29.00 1971 50094400 Río Nigua at Pitahaya 5.86 1965, 1969, 1970-71, 1973 50095200 Río Guamaní at Guayama 8.22 1969-71 50095500 Río Guamaní near Guayama 12.30 1969-70 50099000 Quebrada Aguas Verdes near Salinas 0.39 1989 50106500 Río Coamo near Coamo 46.00 1967-68, 1984-85, 1986 50106900 Río Coamo below Lago Coamo near Coamo 65.40 1967-68 50107200 Río Coamo at mouth near Santa Isabel 69.30 1967-68 50108200 Río Descalabrado at Las Ollas 13.90 1965, 1967-71 50108500 Río Descalabrado near Santa Isabel 18.10 1966-67 50111200 Río Toa Vaca near Villalba 21.40 1966-70 XVI WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 DISCONTINUED STREAMFLOW STATIONS--Continued Station Station name Drainage Period of number area (mi2) record 50111700 Río Jacaguas near Juana Díaz 53.20 1966-68 50111750 Río Jacaguas below Quebrada Guanábana 56.30 1989 50112100 Río Jacaguas near Arús 59.60 1966-67 50112600 Río Inabón at Coto Laurel -- 1967-71 50113100 Río Guayo near Coto Laurel 11.80 1965, 1968-71 50113500 Río Inabón near Arús 30.20 1964-65 50114400 Río Bucaná near Ponce 25.60 1965-81 50114700 Río Bucaná near Playa de Ponce 28.40 1964-67 50115000 Río Portugués near Ponce 8.82 1964-97 50116500 Río Portugués at Highway 2 Bypass at Ponce 20.50 1964-65 50119000 Río Matilde at Ponce 19.40 1965-66 50121000 Río Tallaboa at Peñuelas 24.20 1959-82 50122000 Río Tallaboa at Tallaboa 31.50 1959-63 50124000 Río Guayanilla nr Guayanilla 18.50 1961-69 50124500 Río Guayanilla at Guayanilla 20.80 1971-82 50125900 Río Duey above Diversion near Yauco 8.93 1977-80 50126150 Río Yauco above Diversion Monserrate near Yauco 27.20 1978-85 50128000 Río Yauco near Yauco 45.50 1962-64, 1977-85 50129000 Río Loco near Yauco 8.50 1963-67 50129500 Río Loco near Guánica 21.00 1963-69 50129900 Laguna Cartagena near Boquerón -- 1984-86 50130320 Quebrada Mamey at Joyuda 0.38 1986-88 50136000 Río Rosario at Rosario 16.40 1975-86 50141000 Río Yahuecas near Adjuntas 15.40 1980-85 50145000 Río Grande de Añasco at El Espino 108.00 1959-66, 1961-63 50147000 Río Culebrinas at San Sebastian 16.70 1960-82 50214500 Quebrada Resaca near Monte Resaca, Culebra 0.23 1991-93 50215000 Drainage Canal at Culebra Airport, Culebra 0.08 1991-93 50231000 Quebrada Confresí Tributary near Isabel II, Vieques 0.28 1991-93 50232000 Quebrada La Mina near Esperanza, Vieques 0.68 1991-96 50233000 Quebrada Pilón at Colonia Puerto Real, Vieques 0.67 1991-96 50276000 Turpentine Run at Mariendal 2.97 1963-69, 1978-86 50292600 Lameshur Bay Gut at Lameshur, St. John 0.38 1992-94 50294000 Fish Bay Gut at Fish Bay, St. John 1.48 1992-94 50295500 Cruz Bay Gut at Cruz Bay, St. John, V 0.09 1992-93 50332000 River Gut at River 1.42 1991-93 50333500 River Gut near Golden Grove 5.40 1990-93 50333700 River Gut at Hwy 66 at Fairplanes 5.89 1990-96 50334500 Bethehem Gut at Hwy 66 at Fairplanes 4.11 1990-96 50337500 Gut 4.5 at Cane Valley 0.2 1991-93 50348000 Salt River at Canaan 0.36 1991-93 50349000 Gut 10 near Altona 0.13 1991-93 1 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 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 U.S. Geological Survey, the data are published annually in this report series entitled "Water Resources Data for Puerto Rico and the U.S. Virgin Islands, 1999." This report includes records on both surface and ground water. Specifically, it contains: (1) discharge records for 76 streamflow gaging stations, daily sediment records for 25 streamflow stations, stage records for 18 reservoirs, and (2) water-quality records for 16 streamflow-gaging stations, and for 42 ungaged stream sites, 11 lake sites, 2 lagoons, and 1 bay, and (3) water-level records for 107 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 to 1998 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 U.S. 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-99-1." 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. 2 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 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 U.S. Geological 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 Emergency Management Agency U.S. Virgin Islands Department of Planning and Natural Resources University of Puerto Rico Funds were also provided by the U.S. Army, Corps of Engineers, for the collection of records at six gaging stations published in this report. 3 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Summary of Hydrologic Conditions Rainfall Rainfall throughout Puerto Rico during the water year 1999 (October 1998 to September 1999) averaged about 107 percent of normal. During the months of October, November, December, January, March, June, July, and September, rainfall was above normal with averages that ranged from 4 to 66 percent above normal (table 1). During the month of February, April, May, and August, rainfall was deficient with averages that ranged from 7 to 46 percent below normal. Rainfall during the water year averaged 100 percent of normal in northern Puerto Rico, 105 percent of normal in southern Puerto Rico, 116 percent of normal in western Puerto Rico, and 110 percent of normal in eastern Puerto Rico. Islandwide monthly average rainfall for the 1999 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 1999 and annual averages for the 30-year reference period, 1961-1990 _________________________________________________ 1999 Water Year 30-year normal Month (inches) (inches) _________________________________________________ October 9.07 8.29 November 7.46 6.55 December 7.27 4.38 January 3.51 2.87 February 1.77 2.53 March 3.14 3.02 April 2.75 4.44 May 3.76 6.96 June 6.98 4.99 July 5.54 5.09 August 6.40 6.89 September 9.76 7.14 TOTAL 67.41 63.15 _________________________________________________ Surface Water Streamflow in Puerto Rico was in general, above normal in water year 1999, based on the index stations. Monthly mean discharges were larger than the long-term monthly mean median flow during several months. A comparison of the monthly mean flows during the 1999 water year, the long-term median of the monthly mean flows, and the minimum and maximum monthly mean flows for the periods of record at the index stations on the Río Grande de Manatí, the Río Fajardo, the Río Inabón, and the Río Grande de Añasco are shown in figure 1. Historical maximums for the month of June were recorded at two of the four index stations. Hydrologic conditions were similar islandwide for the months of October to January, and July to September, with monthly- mean flows at the four index stations above the long-term median of the monthly-mean flows, at those stations. During this year there were no extraordinary streamflow events, but there was sufficient runoff during the entire period. During the months of February to May, streamflows were below the long-term median of the monthly-mean flows in some areas, as recorded by the index stations. An overview of the four areas represented by the index stations follows to describe those conditions in more detail. In the northern area, represenred by the Río Grande de Manatí index station, the monthly mean flows were below the long- term median of the monthly-mean flows only during the months of February, April, and May. Those flows ranged between 2 to 16 percent below normal. The rest of the year, monthly mean flows were well above normal, ranging from 9 to 420 percent above the long-term median of the monthly-mean flows, with December the highest. A historical monthly mean maximum was recorded during the month of June by this index station. 10,000 1,000 10 1 100 NORTE RIO GRANDE DE MANATÍ AT HWY 2 (50038100) 1,000 10 1 100 NORTE RIO FAJARDO NEAR FAJARDO (50071000) 10,000 1,000 10 1 100 Unshaded area indicates range between highest and lowest monthly-mean discharge for the period of record to water year 1999. Figure 1. Monthly-mean discharge of selected streams in Puerto Rico. 1999 MONTHLY MEAN 1965-98 MEDIAN OF MONTHLY-MEAN 1999 MONTHLY MEAN 1964-98 MEDIAN OF MONTHLY-MEAN 1999 MONTHLY MEAN 1962-98 MEDIAN OF MONTHLY-MEAN 1999 MONTHLY MEAN 1961-98 MEDIAN OF MONTHLY-MEAN Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sep. 1998 1999 1998 1999 SOUTH RIO INABÓN AT REAL ABAJO (50112500) Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sep. WEST RIO GRANDE DE AÑASCO NEAR SAN SEBASTIÁN (50144000) Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sep. 1998 1999 1998 1999 1,000 10 1 100 4 5 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 The eastern area, represented by the index station at the Río Fajardo, recorded monthly mean flows above the long-term median during eight of the twelve months of the 1999 water year. At this station, the months from March to June ranged from 1 to 57 percent below normal. The rest of the year, above normal flows ranging from 13 to 282 percent above normal were recorded. In the southern area, the Río Inabón index station recorded monthly mean flows above the long-term median during eleven of the twelve months of the 1999 water year. At this station, only the May mean flow was below the long-term median. The flow in May was 67 percent of normal. The rest of the year, monthly mean flows ranged from 104 to 319 percent of the long-term median. In the western area, the index station on the Río Grande de Añasco recorded monthly mean flows above the long-term median during the entire 1999 water year. Monthly mean flows ranged between 11 to 202 percent above the long-term median of the monthly mean flows. The highest was recorded during the month of June with the historical highest monthly mean since station was started in 1964. In the U.S. Virgin Islands, rainfall was dificient with only91 percent of normal reported by the National Oceanic and Atmospheric Administration. Streamflow conditions were similarly below normal. Ground Water Water level trends and fluctuations during the 1999 water year followed a similar pattern as in previous years resulting from above normal rainfall accumulation combined with continuous ground-water withdrawals (Figure 2). In 39 ground-water monitoring sites, the highest water level recorded approached or was slightly above the historic high (Table 2). Similarly, in areas where the historic water level was below the historic low, ground-water withdrawals are an important resource, for drinking water purposes (Table 3). The period of record of 56 ground-water monitoring sites dates back to 1997, when the ground-water monitoring network was established and a similar pattern, when ground-water levels are compared to historic ground-water levels at index stations. Figure 7 and 9 shows the locations of the ground-water stations maintanied by the USGS in Puerto Rico and the US Virgin Islands. 6 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Table 2. Highest ground-water levels recorded during 1999 water year and previous high ground-water levels at selected wells in Puerto Rico [PR, Puerto Rico; mm/dd/yy, month/day/year; ft-blsd, feet below land-surface datum; mm/yy, month/year] _____________________________________________________________________________________________________ 1999 Previous Highest highest Well water water Period of name or Local level Date level Date record number number Location (ft-blsd) (mm/dd/yy) (ft-blsd) (mm/dd/yy) (mm/yy) _____________________________________________________________________________________________________ Otilio No. 1 1001 PR 292.31 10-09-99 292.40 10-18-98 5-97 to 9-99 10-19-98 Saltos # 1 165 PR 38.24 10-16-98 38.36 07-12-93 1-82 to 9-99 Carmelo Barreto 202 PR 401.95 02-06-99 409.2 09-25-86 11-85 to 9-99 Campo Alegre 1027 PR 183.48 04-09-99 183.90 10-03-96 9-96 to 9-99 # 4 Barreto # 1 1051 PR 159.38 11-01-98 159.6 09-24-98 10-97 to 9-99 11-02-98 to ‘ 11-03-98 09-28-98 Florida Afuera 1054 PR 198.03 12-04-98 199.01 09-11-96 8-96 to 9-99 # 2 12-05-98 09-12-96 Florida # 1 1057 PR 135.73 10-30-98 137.91 09-22-98 8-96 to 9-99 Hill # 2 1076 PR 249.79 12-05-98 267.96 01-24-97 5-96 to 9-99 Palo Alto # 2 1101 PR 220.55 12-06-98 221.78 09-12-96 5-96 to 9-99 Tortuguero 1102 PR 23.39 12-06-98 23.48 09-12-96 5-96 to 9-99 # 3 Maguayo # 2 1128 PR 24.02 12-11-98 24.89 09-18-96 6-95 to 9-99 12-12-98 09-19-96 Higuillar 1129 PR 35.29 01-15-99 36.04 09-15-96 5-96 to 9-99 # 1 09-16-96 Higuillar 1130 PR 31.10 12-11-98 31.84 09-11-96 1-95 to 9-99 # 4 12-12-98 USGS Bldg. 652 PR 5.42 12-05-98 6.20 05-26-98 5-97 to 9-99 652 La Esperanza 1152 PR 7.63 12-06-98 7.71 09-23-98 7-89 to 9-99 # 2 Jardín Botánico 1158 PR 2.05 12-04-98 2.84 09-22-98 6-91 to 9-99 # 3 09-23-98 CJ-TW-19A 1176 PR 21.06 12-07-98 22.07 09-25-98 6-92 to 9-99 09-26-98 09-27-98 CJ-TW-11 1177 PR 18.34 12-06-98 23.08 09-27-98 5-97 to 9-99 12-07-98 09-29-98 12-08-98 CJ-TW-20 1178 PR 11.75 12-07-98 14.19 09-22-98 5-97 to 9-99 CJ-TW-15 1179 PR 4.92 12-03-98 5.93 10-14-97 5-97 to 9-99 CJ-TW-3B 1181 PR 9.18 11-15-98 10.64 09-11-96 9-91 to 9-99 11-16-98 Río Espíritu 1201 PR +0.36 12-04-98 0.41 02-02-97 12-96 to 9-99 Santo 2A 12-05-98 Río Mameyes 1202 PR 9.30 07-30-99 9.35 06-01-98 9-97 to 9-99 # 2 07-31-99 Arroyo TW-1 1203 PR 2.01 10-22-98 4.95 01-07-98 10-97 to 9-99 Río Pitahaya 1205 PR 0.32 12-10-98 0.91 09-18-95 8-95 to 9-99 No. 4 Río Fajardo 1207 PR 1.90 12-30-98 2.71 10-14-97 8-95 to 9-99 No. 12 Yabucoa Deep 1226 PR +0.05 12-09-98 0.50 03-02-98 9-97 to 9-99 Observation 03-03-98 03-04-98 7 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Table 3. Lowest ground-water levels recorded during 1999 water year and previous low ground-water levels at selected wells in Puerto Rico [PR, Puerto Rico; mm/dd/yy, month/day/year; ft-blsd, feet below land-surface datum; mm/yy, month/year] _____________________________________________________________________________________________________ 1999 Previous Lowest Lowest Well water water Period of name or Local level Date level Date record number number Location (ft-blsd) (mm/dd/yy) (ft-blsd) (mm/dd/yy) (mm/yy) _____________________________________________________________________________________________________ Monserrate 217 PR 4.11 06-30-99 3.72 05-13-95 11-85 to 9-99 # 2 USGS Bldg. 652 PR 9.16 10-01-98 9.02 12-13-97 5-97 to 9-99 652 12-14-97 CJ-TW-18 1180 PR 15.83 05-11-99 15.81 07-15-97 6-97 to 9-99 07-16-97 07-17-97 Río Mameyes 1202 PR 14.22 05-06-99 14.08 05-26-98 9-97 to 9-99 # 2 05-07-99 05-08-99 Arroyo TW-1 1203 PR 11.68 07-08-99 10.65 04-06-98 10-97 to 9-99 07-09-99 Río Fajardo 1207 PR 12.40 08-17-99 10.64 08-21-97 8-95 to 9-99 No. 12 08-18-99 08-22-97 Yabucoa Deep 1226 PR 5.90 08-09-99 5.83 06-10-98 9-97 to 9-99 Observation 08-10-99 to 08-11-99 06-17-98 Algarrobos 1228 PR 34.17 07-06-99 33.85 07-02-98 5-97 to 9-99 to 07-11-99 08-22-99 08-23-99 Cabo Rojo 1301 PR 28.52 05-19-99 28.41 04-08-98 5-96 to 9-99 # 1 CR-TW-9A 1302 PR 13.39 06-02-99 8.53 03-21-98 7-92 to 9-99 Cervecería 1326 PR 18.86 04-24-99 18.82 10-22-97 8-97 to 9-99 India Rincón # 4 1352 PR 34.38 08-19-99 34.07 05-30-96 5-96 to 9-99 _____________________________________________________________________________________________________ 8 Figure 2. Ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 October November December January February March April May June July August September 1999 0 20 0 5 10 15 October November December January February March April May June July August September 1999 36 42 36 38 40 October November December January February March April May June July August September 1999 24 32 24 26 28 30 WELL 70, SABANA HOYOS, PUERTO RICO WELL 87, ALOMAR WELL, PUERTO RICO WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM WELL 11, GUINEA GUT ST. JOHN U.S. VIRGIN ISLANDS 9 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Water Quality The U.S. Geological Survey, in cooperation with several local government agencies, collected water-quality data at 73 surface-water stations in Puerto Rico during water year 1999. The water-quality data collected at these stations included the major chemical constituents and several others that are listed in table 4. The highest concentration of each of these constituents detected during water year 1999 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 1999 [All constituent concentrations are in milligrams per liter; MBAS, Methylene blue active substance] ________________________________________________________________________________ Station number Station name Constituent Concentration ________________________________________________________________________________ * -- Sulfide <1.0 50047530 Río Hondo at Flood Channel Boron 0.35 50031200 Río Grande de Manatí nr. Morovis Manganese 1.0 50031200 Río Grande de Manatí nr. Morovis Iron 27 50055250 Río Cagüitas at hwy 30 nr. Caguas Zinc 0.23 50091000 Río Maunabo nr. Maunabo Cyanide 0.308 50057025 Río Gurabo nr. Gurabo Phenols 0.28 50055250 Río Cagüitas at hwy 30 nr. Caguas MBAS 1.4 * Sulfide concentrations at all water-quality stations were below the detection limit (<1.0). 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 1999 . The highest concentration observed during this year ocurred in stations 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 the upper basin sewage treatment plants. 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 of the Island. Suspended-sediment concentrations were monitored at 25 stations in Puerto Rico during the 1999 water year 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 activities where soil movement was involved. The high suspended- sediment concentrations affect the quality of drinking water and the storage capacities of reservoirs. Water quality data for purposes other than long-term network monitoring were obteined at selected stations located in Laguna Tortuguero, Puerto Rico and in Saint Thomas, U.S. Virgin Island. The results are included in the miscellaneous station analysis section beginning on page 439 of this report. 10 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 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 (NAWQA) 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 1999 water year that began October 1, 1998 and ended September 30, 1999. 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 9. 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. 11 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Station Identification Numbers Each data station, whether stream site 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. 10). Laguna Tortuguero Río Culebrinas Río Guajataca Río Camuy Río Grande de Arecibo Río Grande de Manatí Río Cibuco Río de la Plata Río Hondo Río de Bayamón Bahía de San Juan Río Piedras Laguna San José Laguna La Torrecilla Quebrada Blasina Río Grande de Loíza Río Herrera Río Espíritu Santo Río Mameyes Río Sabana Río Juan Martín Río Guayabo Río Grande Río Grande de Añasco Río Yagüez Río Guanajibo Río Loco Río Yauco Río Guayanilla Río Tallaboa Río Matilde Río Portugués Río Bucaná Río Inabón Río Jacaguas Río Cañas Río Descalabrado Río Coamo Río Jueyes Río Salinas Río Seco Río Guamaní Río Nigua Río Grande de Patillas Río Chico Río Jacaboa Río Maunabo Río Fajardo Río Daguao Quebrada Palma Río Santiago Río Blanco Río Antón Ruíz Río Humacao Río Guayanés ATLANTIC OCEAN CARIBBEAN SEA 67°15' 18°30' 15' 18°00' 17°45' 67°00' 45' 30' 15' 66°00' 45' 65°30' FECAL COLIFORM Figure 3. Location of maximum concentration of fecal coliform bacteria at the water-quality sampling sites in Puerto Rico. < 1,000 1,000 - 10,000 10,000 - 100,000 100,000 - 1,000,000 12 EXPLANATION 0 0 10 10 20 KILOMETERS 20 MILES Laguna Tortuguero Río Culebrinas Río Guajataca Río Camuy Río Grande de Arecibo Río Grande de Manatí Río Cibuco Río de la Plata Río Hondo Río de Bayamón Bahía de San Juan Río Piedras Laguna San José Laguna La Torrecilla Quebrada Blasina Río Grande de Loíza Río Herrera Río Espíritu Santo Río Mameyes Río Sabana Río Juan Martín Río Guayabo Río Grande Río Grande de Añasco Río Yagüez Río Guanajibo Río Loco Río Yauco Río Guayanilla Río Tallaboa Río Matilde Río Portugués Río Bucaná Río Inabón Río Jacaguas Río Cañas Río Descalabrado Río Coamo Río Jueyes Río Salinas Río Seco Río Guamaní Río Nigua Río Grande de Patillas Río Chico Río Jacaboa Río Maunabo Río Fajardo Río Daguao Quebrada Palma Río Santiago Río Blanco Río Antón Ruíz Río Humacao Río Guayanés ATLANTIC OCEAN CARIBBEAN SEA 67°15' 18°30' 15' 18°00' 17°45' 67°00' 45' 30' 15' 66°00' 45' 65°30' FECAL STREPTOCOCCI Figure 4. Location of maximum concentration of fecal streptococci bacteria at the water-quality sampling sites in Puerto Rico. < 1,000 1,000 - 10,000 10,000 - 100,000 100,000 - 1,000,000 13 EXPLANATION 0 0 10 10 20 KILOMETERS 20 MILES Laguna Tortuguero Río Culebrinas Río Guajataca Río Camuy Río Grande de Arecibo Río Grande de Manatí Río Cibuco Río de la Plata Río Hondo Río de Bayamón Bahía de San Juan Río Piedras Laguna San José Laguna La Torrecilla Quebrada Blasina Río Grande de Loíza Río Herrera Río Espíritu Santo Río Mameyes Río Sabana Río Juan Martín Río Guayabo Río Grande Río Grande de Añasco Río Yagüez Río Guanajibo Río Loco Río Yauco Río Guayanilla Río Tallaboa Río Matilde Río Portugués Río Bucaná Río Inabón Río Jacaguas Río Cañas Río Descalabrado Río Coamo Río Jueyes Río Salinas Río Seco Río Guamaní Río Nigua Río Grande de Patillas Río Chico Río Jacaboa Río Maunabo Río Fajardo Río Daguao Quebrada Palma Río Santiago Río Blanco Río Antón Ruíz Río Humacao Río Guayanés ATLANTIC OCEAN CARIBBEAN SEA 67°15' 18°30' 15' 18°00' 17°45' 67°00' 45' 30' 15' 66°00' 45' 65°30' Figure 5. Location of surface-water stations in Puerto Rico. CONTINUOUS STREAMFLOW STATION AND NUMBER LAKE-ELEVATION STATION AND NUMBER SEDIMENT STATION AND NUMBER 093045 053025 0905 14 EXPLANATION 0 0 10 10 20 KILOMETERS 20 MILES 0710 0618 0570 0550 0551 047850 047550 0438 032290 111210 113950 1002 1061 1080 1115 1113 114390 1138 1149 1159 1242 0201 1289 1415 0108 125780 1364 1380 1125 100450 0920 039990 093045 038320 0395 0381 027750 0284 0290 0280 0148 0105 1478 148890 1440 0157 0350 0312 0340 0590 059050 048770 048680 048690 0491 0460 045010 0450 0564 0810 051310 0509 053025 051150 051180 0655 0670 0660 063440 074950 0750 0705 0638 131990 1140 026140 0271 026025 047560 047540 047535 0642 0518 0905 055750 055225 055390 058350 030460 1109 032590 Laguna Tortuguero Río Culebrinas Río Guajataca Río Camuy Río Grande de Arecibo Río Grande de Manatí Río Cibuco Río de la Plata Río Hondo Río de Bayamón Bahía de San Juan Río Piedras Laguna San José Laguna La Torrecilla Quebrada Blasina Río Grande de Loíza Río Herrera Río Espíritu Santo Río Mameyes Río Sabana Río Juan Martín Río Guayabo Río Grande Río Grande de Añasco Río Yagüez Río Guanajibo Río Loco Río Yauco Río Guayanilla Río Tallaboa Río Matilde Río Portugués Río Bucaná Río Inabón Río Jacaguas Río Cañas Río Descalabrado Río Coamo Río Jueyes Río Salinas Río Seco Río Guamaní Río Nigua Río Grande de Patillas Río Chico Río Jacaboa Río Maunabo Río Fajardo Río Daguao Quebrada Palma Río Santiago Río Blanco Río Antón Ruíz Río Humacao Río Guayanés ATLANTIC OCEAN CARIBBEAN SEA 67°15' 18°30' 15' 18°00' 17°45' 67°00' 45' 30' 15' 66°00' 45' 65°30' CHEMICAL STATION AND NUMBER (Quaterly) BIOLOGICAL STATION AND NUMBER (Quaterly) SEDIMENT STATION AND NUMBER 0550 0910 0918 Figure 6. Location of water-quality stations in Puerto Rico. 15 EXPLANATION 0725 0710 0820 0865 0835 0910 0918 0920 0399 0430 0312 0307 1065 1140 1162 1150 1247 1336 1364 1388 1440 1491 1430 1476 0114 0110 010790 010720 1460 1380 1297 0250 025110 027090 027250 026050 0355 0381 0290 0280 0105 0205 020050 035950 0440 0444 0460 0382 0395 044850 038320 044950 039950 0550 0476 047537 047549 0575 0554 0588 0590 0591 0503 0491 0488 047990 047530 048510 049820 049920 057025 055250 0638 0 0 10 10 20 KILOMETERS 20 MILES Laguna Tortuguero Río Culebrinas Río Guajataca Río Camuy Río Grande de Arecibo Río Grande de Manatí Río Cibuco Río de la Plata Río Hondo Río de Bayamón Bahía de San Juan Río Piedras Laguna San José Laguna La Torrecilla Quebrada Blasina Río Grande de Loíza Río Herrera Río Espíritu Santo Río Mameyes Río Sabana Río Juan Martín Río Guayabo Río Grande Río Grande de Añasco Río Yagüez Río Guanajibo Río Loco Río Yauco Río Guayanilla Río Tallaboa Río Matilde Río Portugués Río Bucaná Río Inabón Río Jacaguas Río Cañas Río Descalabrado Río Coamo Río Jueyes Río Salinas Río Seco Río Guamaní Río Nigua Río Grande de Patillas Río Chico Río Jacaboa Río Maunabo Río Fajardo Río Daguao Quebrada Palma Río Santiago Río Blanco Río Antón Ruíz Río Humacao Río Guayanés ATLANTIC OCEAN CARIBBEAN SEA 67°15' 18°30' 15' 18°00' 17°45' 67°00' 45' 30' 15' 66°00' 45' 65°30' WELL AND NUMBER 1235 Figure 7. Location of ground-water stations in Puerto Rico. 16 EXPLANATION 222 1201 1204 1208 1205 1207 1206 1203 1202 1131 1132 1129 1130 1128 1127 1126 212 213 211 204 207 166 1103 1077 1076 1101 1102 210 206 219 1151 1159 217 216 1133 70 1152 1153 1154 1155 1158 1156 96 1226 1235 6 1251 1254 1258 1257 1256 1237 1236 1228 1229 1239 1238 1230 1252 1260 1134 1253 87 132 143 1279 1231 1233 1232 1234 200 1352 165 1001 202 1026 1051 1027 1055 1056 1052 1053 1054 205 1057 50 141 1258 1239 1276 1277 1278 1176 1177 1179 1178 1181 1180 1301 1302 1303 1304 1326 0 0 10 10 20 KILOMETERS 20 MILES + Bonne Resolution Jolly Hill Gut Salt River Cob Gut Guinea Bay Gut Gut Gut Battery Fish T u r p en tine Run Westend Saltpond ST. CROIX EXPLANATION Green Cay CHRISTIANSTED FREDERIKSTED C A R I B B E A N S E A C A R I B B E A N S E A Buck Island ST. JOHN C A R I B B E A N S E A A T L A N T I C O C E A N Flannagan Island Coral Bay Whistling Cay Congo Cay Lovango Cay Windward Passage Pillsbury Sound Durloe Cays Leduck Island S a b b a t n Cha n e l CRUZ BAY ST. THOMAS Sula Cay Capella Islands Little St. James I Dog Island Great St. James I Shark Island Mingo Cay Grass Cay CHARLOTTE AMALIE A T L A N T I C O C E A N C A R I B B E A N S E A Cricket Rock Cockroach Island Dutchcap Cay Salt Cay West Cay Kalkun Cay Savana Island Turtledove Cay Saba Island Flat Cays Outer Brass Island Hans Lollik Island Little Hans Lollik Island Water Island 1 2 MILES 1 2 KILOMETERS 0 0 1 2 MILES 1 2 KILOMETERS 0 0 1 2 MILES 1 2 KILOMETERS 0 0 17 Figure 8. Location of surface-water stations in the U.S. Virgin Islands. SURFACE-WATER STATION AND NUMBER EXPLANATION 3450 3450 2950 2520 2740 + Bonne Resolution 18 Jolly Hill Gut Salt River Cob Gut Guinea Bay Gut Gut Gut Battery Fish T u r p en tine Run Westend Saltpond ST. CROIX Figure 9. Location of ground-water stations in the U.S. Virgin Islands. WELL AND WELL NUMBER EXPLANATION 2 Green Cay CHRISTIANSTED FREDERIKSTED C A R I B B E A N S E A C A R I B B E A N S E A Buck Island ST. JOHN C A R I B B E A N S E A A T L A N T I C O C E A N Flannagan Island Coral Bay Whistling Cay Congo Cay Lovango Cay Windward Passage Pillsbury Sound Durloe Cays Leduck Island S a b b a t n Cha n e l CRUZ BAY ST. THOMAS Sula Cay Capella Islands Little St. James I Dog Island Great St. James I Shark Island Mingo Cay Grass Cay CHARLOTTE AMALIE A T L A N T I C O C E A N C A R I B B E A N S E A Cricket Rock Cockroach Island Dutchcap Cay Salt Cay West Cay Kalkun Cay Savana Island Turtledove Cay Saba Island Flat Cays Outer Brass Island Hans Lollik Island Little Hans Lollik Island Water Island 1 2 MILES 1 2 KILOMETERS 0 0 1 2 MILES 1 2 KILOMETERS 0 0 1 2 MILES 1 2 KILOMETERS 0 0 2 3 13 11 8 6 19 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Figure 10. Grid showing system for numbering wells 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. 134 132 131 27 74 16 COORDINATES FOR WELLS 27 (180150066474900) AND 74 (180135066471000) COORDINATES FOR WELLS 132 (180133066503300 AND 134 (180120066503200) COORDINATES FOR WELLS 131 (180058066502700 COORDINATES FOR WELLS 16 (175922066495800) 20 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 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, 1999 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, 1999 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 the 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, 1999 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 ft3/s. 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, 1999 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. A1, 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, 1999 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. C1. Methods used by the Geological Survey laboratories are given in TWRI, Book 1, Chap. D2; Book 3, Chap. C2; Book 5, Chap. A1, A3, and A4. 26 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 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, 1999 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 9. 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 (lsd). 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, 1999 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 measurement 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, 1999 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, 1999 DEFINITION OF TERMS Terms related to streamflow, water-quality, and other hydrologic data, as used in this report, are defined below. See also table for converting English units to International System (SI) Units on the inside of the back cover. Acid neutralizing capacity (ANC) is the equivalent sum of all bases or base-producing materials, solutes plus particulates, in an aqueous system that can be titrated with acid to an equivalence point. This term designates titration of an “unfiltered” sample (formerly reported as alkalinity). Acre-foot (AC-FT, acre-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, 325,851 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 measurement of ATP therefore provides a sensitive and rapid estimate of biomass. ATP is reported in micrograms per liter. Algae are mostly aquatic single-celled, colonial, or multicelled plants containing chlorophyll and lacking roots, stems, and leaves. Algal 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 at stationary phase and is expressed as milligrams dry weight of algae produced per liter of sample. Alkalinity is the capacity of solutes in an aqueous system to neutralize acid. This term designates titration of a “filtered” sample. Annual runoff is the total quantity of water in runoff for a drainage area for the year. Data reports may use any of the following units of measurement in presenting annual runoff data: 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 43,560 cubic feet, 325,851 gallons, or 1,233 cubic meters Cubic foot per second per square mile [CFSM, (ft3/s)/mi2] 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. Inch (IN., in.) as used in this report, refers to the depth to which the drainage area would be covered with water if all of the runoff for a given time period were uniformly distributed on it. Aroclor is the registered trademark for a group of polychlorinated biphenyls that were manufactured by the Monsanto Company prior to 1976. Aroclors are assigned specific 4-digit reference numbers dependent upon molecular type and degree of substitution of the biphenyl ring hydrogen atoms by chlorine atoms. The first two digits of a numbered aroclor represent the molecular type and the last two digits represent the weight percent of the hydrogen substituted chlorine. 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. This group includes coliforms that inhabit the intestine of warm-blooded animals and those that inhabit soils. They are characterized as aerobic or facultative anaerobic, gram-negative, nonspore-forming, rod-shaped bacteria that ferment lactose with gas formation within 48 hours at 35 °C. In the laboratory, these bacteria are defined as all the organisms that produce colonies with a golden-green metallic sheen within 24 hours when incubated at 35 °C plus or minus 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. Fecal coliform bacteria are bacteria that are present in the intestine 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 that produce blue colonies within 24 hours when incubated at 44.5 °C plus or minus 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 in the intestine of warm-blooded animals. Their presence in water is considered to verify fecal pollution. They are characterized as gram-positive, cocci bacteria that are capable of growth in brain-heart infusion broth. In the laboratory, they are defined as all the organisms that produce red or pink colonies within 48 hours at 35 °C plus or minus 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. 31 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Enterococcus bacteria are commonly found in the feces of humans and other warm-blooded animals. Although some strains are ubiquitous and not related to fecal pollution, the presence of enterococci in water is an indication of fecal pollution and the possible presence of enteric pathogens. Enterococcus bacteria are those bacteria that produce pink to red colonies with black or reddish-brown precipitate after incubation at 41 °C on mE agar and subsequent transfer to EIA medium. Enterococci include Streptococcus feacalis, Streptococcus feacium, Streptococcus avium, and their variants. Escherichia coli (E. coli) are bacteria present in the intestine and feces of warm-blooded animals. E. coli are a member species of the fecal coliform group of indicator bacteria. In the laboratory, they are defined as those bacteria that produce yellow or yellow-brown colonies on a filter pad saturated with urea substrate broth after primary culturing for 22 to 24 hours at 44.5 ˚C on mTEC medium. Their concentrations are expressed as number of colonies per 100 mL of sample. Base flow is flow in a channel sustained by ground-water discharge in the absence of direct runoff. Bed material is the sediment mixture of which a streambed, lake, pond, reservoir, or estuary bottom is composed. Benthic organisms (invertebrates) are the group of animals inhabiting the bottom of an aquatic environment. They include a number of types of organisms, such as bacteria, fungi, insect larvae and nymphs, snails, clams, and crayfish. They are useful as indicators of water quality. 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 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. Ash mass of zooplankton and phytoplankton is 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 is 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 ash mass and represents the actual mass of the living matter. Organic mass is expressed in the same units as for ash mass and dry mass. Wet mass is the mass of living matter plus contained water. Biomass pigment ratio is an indicator of the total proportion of periphyton which are autotrophic (plants). This is also called the Autotrophic Index. Bottom material: See “Bed material.” Cells/volume refers to the number of plankton cells or natural units counted using a microscope and grid or counting cell. Results are generally reported as cells or units per milliliter. Cells volume (biovolume) determination is one of several common methods used to estimate biomass of algae in aquatic systems. Cell members of algae are frequently used in aquatic surveys as an indicator of algal production. However, cell numbers alone cannot represent true biomass because of considerable cell-size variation among the algal species. Cell volume (µm3) is determined by obtaining critical cell measurements on cell dimensions (for example, length, width, height, or radius) for 20 to 50 cells of each important species to obtain an average biovolume per cell. Cells are categorized according to the correspondence of their cellular shape to the nearest geometric solid or combinations of simple solids (for example, spheres, cones, or cylinders). Representative formulae used to compute biovolume are as follows: sphere 4/3 πr3 cone 1/3 πr3h cylinder πr3h. From cell volume, total algal biomass expressed as biovolume (µm3/mL) is thus determined by multiplying the number of cells of a given species by its average cell volume and then summing these volumes over all species. 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 BOD or with carbonaceous organic pollution from sewage or industrial wastes. 32 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Chlorophyll refers to the green pigments of plants. Chlorophyll a and b are the two most common green pigments in plants. Colloid is any substance with particles in such a fine state of subdivision dispersed in a medium (for example, water) that they do not settle out; but not in so fine a state of subdivision that they can be said to be truly dissolved. Color unit is produced by 1 milligram per liter of platinum in the form of the chloroplatinate ion. Color is expressed in units of the platinum-cobalt scale. Confined aquifer is a term used to describe an aquifer containing water between two relatively impermeable boundaries. The water level in a well tapping a confined aquifer stands above the top of the confined aquifer and can be higher or lower than the water table that may be present in the material above it. In some cases the water level can rise above the ground surface, yielding a flowing well. 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. Continuous-record station is a site that meets either of the following conditions: 1.Stage or streamflow are recorded at some interval on a continuous basis. The recording interval is usually 15 minutes, but may be less or more frequent. 2.Water-quality, sediment, or other hydrologic measure-ments are recorded at least daily. Control designates a feature in the channel downstream from a gaging station that physically influences the water-surface elevation and thereby determines the stage-discharge relation at the station. This feature may be a constriction of the channel, a bedrock outcrop, a gravel bar, 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 saltwater. Cubic foot per second (CFS, ft3/s) is the rate of discharge representing a volume of 1 cubic foot passing a given point in 1 second. It is equivalent to approximately 7.48 gallons per second, 448.8 gallons per minute, or 0.02832 cubic meters per second. Cubic foot per second-day (CFS-DAY, Cfs-day, [(ft3/s)/d]) 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, 1.9835 acre-feet, 646,317 gallons, or 2,447 cubic meters. Daily record is a summary of streamflow, sediment, or water-quality values computed from data collected with sufficient frequency to obtain reliable estimates of daily mean values. Daily record station is a site for which daily records of streamflow, sediment, or water-quality values are computed. Datum, as used in this report, is an elevation above mean sea level to which all gage height readings are referenced. Diel is of or pertaining to a 24-hour period of time; a regular daily cycle. Discharge, or flow, is the volume of water (or more broadly, volume of fluid including solid- and dissolved-phase material), that passes a given point in a given period of time. Annual 7-day minimum is the lowest mean discharge for 7 consecutive days in a 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.) 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. Dissolved refers to that material in a representative water sample that passes through a 0.45-micrometer 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. 33 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Dissolved oxygen (DO) content of water in equilibrium with air is a function of atmospheric pressure, temperature, and dissolved-solids concentration of the water. The ability of water to retain oxygen decreases with increasing temperature or dissolved solids, with small temperature changes having the more significant offset. Photosynthesis and respiration may cause diurnal variations in dissolved-oxygen concentration in water from some streams. 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 that analytical determination of dissolved solids, the bicarbonate (generally a major dissolved component of water) is converted to carbonate. Therefore, in the mathematical calculation of dissolved-solids concentration, the bicarbonate value, in milligrams per liter, is multiplied by 0.4926 to reflect the change. Alternatively, alkalinity concentration (as mg/L CaCO3) can be converted to carbonate concentration by multiplying by 0.60. Diversity index is a numerical expression of evenness of distribution of aquatic organisms. The formula for diversity index is: 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 site on a stream is that area, measured in a horizontal plane, that has a common outlet at the site for its surface runoff. Figures of drainage area given herein include all closed basins, or noncontributing areas, within the area unless otherwise specified. Drainage basin is a part of the Earth’s surface that is occupied by a drainage system with a common outlet for its surface runoff (see “Drainage area”). Dry weight refers to the weight of animal tissue after it has been dried in an oven at 65 ˚C until a constant weight is achieved. Dry weight represents total organic and inorganic matter in the tissue. Flow-duration percentiles are values on a scale of 100 that indicate the percentage of time for which a flow is not exceeded. For example, the 90th percentile of river flow is greater than or equal to 90 percent of all recorded flow rates. Gage datum is the elevation of the zero point of the reference gage from which gage height is determined as compared to sea level (see “Datum”). This elevation is established by a system of levels from known benchmarks, by approximation from topographic maps, or by geographical positioning system. Gage height (G.H.) is the water-surface elevation referenced to the 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 site on a stream, canal, lake, or reservoir where systematic observations of stage, discharge, or other hydrologic data are obtained. When used in connection with a discharge record, the term is applied only to those gaging stations where a continuous record of discharge is computed. Gas chromatography/flame ionization detector (GC/FID) is a laboratory analytical method used as a screening technique for semivolatile organic compounds that are extractable from water in methylene chloride . Ground-water level is the elevation of the water table or another potentiometric surface at a particular location. 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 the equivalent concentration of calcium carbonate (CaCO3). High tide is the maximum height reached by each rising tide. The high-high and low-high tides are the higher and lower of the two high tides, respectively, of each tidal day. See NOAA web site: http://www.co-ops.nos.noaa.gov/tideglos.html Hydrologic benchmark station is one that provides hydrologic data for a basin in which the hydrologic regimen will likely be governed solely by natural conditions. Data collected at a benchmark station may be used to separate effects of natural from human-induced changes in other basins that have been developed and in which the physiography, climate, and geology are similar to those in the undeveloped benchmark basin. d ni n--- i 1 ≈ s ∑ ni n--- 2 log – = 34 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Hydrologic unit is a geographic area representing part or all of a surface drainage basin or distinct hydrologic feature as defined by the former Office of Water Data Coordination and delineated on the State Hydrologic Unit Maps by the U.S. Geological Survey. Each hydrologic unit is identified by an 8-digit number. Land-surface datum (lsd) is a datum plane that is approximately at land surface at each ground-water observation well . Light-attenuation coefficient, also known as the extinction coefficient, is a measure of water clarity. Light is attenuated according to the Lambert-Beer equation where Io is the source light intensity, I is the light intensity at length L (in meters) from the source, λ is the light-attenuation coefficient, and e is the base of the natural logarithm. The light attenuation coefficient is defined as Lipid is any one of a family of compounds that are insoluble in water and that make up one of the principal components of living cells. Lipids include fats, oils, waxes, and steroids. Many environmental contaminants such as organochlorine pesticides are lipophilic. Low tide is the minimum height reached by each falling tide. The high-low and low-low tides are the higher and lower of the two low tides, respectively, of each tidal day. See NOAA web site: http://www.co-ops.nos.noaa.gov/tideglos.html Macrophytes are the macroscopic plants in the aquatic environment. The most common macrophytes are the rooted vascular plants that are usually arranged in zones in aquatic ecosystems and restricted in the area by the extent of illumination through the water and sediment deposition along the shoreline. Measuring point (MP) is an arbitrary permanent reference point from which the distance to water surface in a well is measured to obtain water level. Membrane filter is a thin microporous material of specific pore size used to filter bacteria, algae, and other very small particles from water. 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 (UG/G, µg/g) is a unit expressing the concentration of a chemical constituent as the mass (micrograms) of the element per unit mass (gram) of material analyzed. Micrograms per kilogram (UG/KG, µg/kg) is a unit expressing the concentration of a chemical constituent as the mass (micrograms) of the constituent per unit mass (kilogram) of the material analyzed. One microgram per kilogram is equivalent to 1 part per billion. Micrograms per liter (UG/L, µg/L) is a unit expressing the concentration of chemical constituents in water as mass (micrograms) of constituent per unit volume (liter) of water. One thousand micrograms per liter is equivalent to 1 milligram per liter. Microsiemens per centimeter (US/CM, µS/cm) is a unit expressing the amount of electrical conductivity of a solution as measured between opposite faces of a centimeter cube of solution at a specified temperature. Siemens is the International System of Units nomenclature. It is synonymous with mhos and is the reciprocal of resistance in ohms. Milligrams per liter (MG/L, mg/L) is a unit for expressing the concentration of chemical constituents in water as the mass (milligrams) of constituent per unit volume (liter) of water. Concentration of suspended sediment also is expressed in mg/L and is based on the mass of dry sediment per liter of water-sediment mixture. I Ioe λL – = λ 1 L-- e log I Io ---- – = 35 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Miscellaneous site, or miscellaneous station, is a site where streamflow, sediment, and/or water-quality data are collected once, or more often on a random or discontinuous basis. Most probable number (MPN) is an index of the number of coliform bacteria that, more probably than any other number, would give the results shown by the laboratory examination; it is not an actual enumeration. MPN is determined from the distribution of gas-positive cultures among multiple inoculated tubes. Multiple-plate samplers are artificial substrates of known surface area used for obtaining benthic invertebrate samples. They consist of a series of spaced, hardboard plates on an eyebolt. Nanograms per liter (NG/L, ng/L) is a unit expressing the concentration of chemical constituents in solution as mass (nanograms) of solute per unit volume (liter) of water. One million nanograms per liter is equivalent to 1 milligram per liter. National Geodetic Vertical Datum of 1929 (NGVD of 1929) is a geodetic datum derived from a general adjustment of the first order level nets of the United States and Canada. It was formerly called “Sea Level Datum of 1929” or “mean sea level” in this series of reports. Although the datum was derived from the average sea level over a period of many years at 26 tide stations along the Atlantic, Gulf of Mexico, and Pacific Coasts, it does not necessarily represent local mean sea level at any particular place. See NOAA web site: http://www.ngs.noaa.gov/faq.shtml#WhatVD29VD88 Nekton are the consumers in the aquatic environment and consist of large free-swimming organisms that are capable of sustained, directed mobility. Nephelometric turbidity unit (NTU) is the measurement for reporting turbidity that is based on use of a standard suspension of Formazin. Turbidity measured in NTU uses nephelometric methods that depend on passing specific light of a specific wavelength through the sample. Open or screened interval is the length of unscreened opening or of well screen through which water enters a well, in feet below land surface. Organic carbon (OC) is a measure of organic matter present in aqueous solution, suspension, or bottom sediments. May be reported as dissolved organic carbon (DOC), suspended organic carbon (SOC), or total organic carbon (TOC). 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 area habitat, usually square meter (m2), acre, 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 milliliter (mL) or liter (L). Numbers of planktonic organisms can be expressed in these terms. Total organism count is the total number of organisms collected and enumerated in any particular sample. Organochlorine compounds are any chemicals that contain carbon and chlorine. Organochlorine compounds that are important in investigations of water, sediment, and biological quality include certain pesticides and industrial compounds. Parameter Code is a 5-digit number used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property. Partial-record station is a site where discrete measurements of one or more hydrologic parameters are obtained over a period of time without continuous data being recorded or computed. A common example is a crest-stage gage partial-record station at which only peak stages and flows are recorded. Particle size is the diameter, in millimeters (mm), of a particle determined by sieve or sedimentation methods. The sedimentation method utilizes the principle of Stokes Law to calculate sediment particle sizes. Sedimentation methods (pipet, bottom-withdrawal tube, visual-accumulation tube, Sedigraph) 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). 36 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Particle-size classification used in this report agrees with the recommendation made by the American Geophysical Union Subcommittee on Sediment Terminology. The classification is as follows: 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. ____________________________________________________ Classification Size (mm) Method of analysis ____________________________________________________ Clay 0.00024 - 0.004 Sedimentation Silt 0.004 - 0.062 Sedimentation Sand 0.062 - 2.0 Sedimentation/sieve Gravel 2.0 - 64.0 Sieve ____________________________________________________ Percent composition or percent of total 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, weight, or volume. Periodic station is a site where stage, discharge, sediment, chemical, or other hydrologic measurements are made one or more times during a year, but at a frequency insufficient to develop a daily record. 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. Periphyton are useful indicators of water quality. Pesticides are chemical compounds used to control undesirable organisms. Major categories of pesticides include insecticides, miticides, fungicides, herbicides, and rodenticides. pH of water is the negative logarithm of the hydrogen-ion activity. Solutions with pH less than 7 are termed “acidic,” and solutions with a pH greater than 7 are termed “basic.” Solutions with a pH of 7 are neutral. The presence and concentration of many dissolved chemical constituents found in water are, in part, influenced by the hydrogen-ion activity of water. Biological processes including growth, distribution of organisms, and toxicity of the water to organisms are also influenced, in part, by the hydrogen-ion activity of water . Picocurie (PC, pCi) is one trillionth (1 x 10-12) of the amount of radioactivity represented by a curie (Ci). A curie is the amount of radioactivity that yields 3.7 x 1010 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. Concentrations are expressed as a number of cells per milliliter (cells/mL of sample). Phytoplankton is the plant part of the plankton. They are usually microscopic, and their movement is subject to the water currents. Phytoplankton 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 (Cyanophyta) 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. Euglenoids (Euglenophyta) are a group of algae that are usually free-swimming and rarely creeping. They have the ability to grow either photosynthetically in the light or heterotrophically in the dark. Fire algae (Pyrrhophyta) are a group of algae that are free-swimming unicells characterized by a red pigment spot. 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. 37 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 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. Polychlorinated biphenyls (PCB’s) are industrial chemicals that are mixtures of chlorinated biphenyl compounds having various percentages of chlorine. They are similar in structure to organochlorine insecticides. Polychlorinated naphthalenes (PCN’s) are industrial chemicals that are mixtures of chlorinated naphthalene compounds. They have properties and applications similar to polychlorinated biphenyls (PCB’s) and have been identified in commercial PCB preparations. 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 (carbon method) by the plants. Primary productivity (carbon method) is expressed as milligrams of carbon per area per unit time [mg C/ (m2/time)] for periphyton and macrophytes or per volume [mg C/(m3/time)] for phytoplankton. Carbon method defines 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 the hour or day, depending on the incubation period. Primary productivity (oxygen method) is expressed as milligrams of oxygen per area per unit time [mg O/ (m2/time)] for periphyton and macrophytes or per volume [mg O/(m3/time)] for phytoplankton. Oxygen method defines 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. Radioisotopes are isotopic forms of an element that exhibit radioactivity. Isotopes are varieties of a chemical element that differ in atomic weight, but are very nearly alike in chemical properties. The difference arises because the atoms of the isotopic forms of an element differ in the number of neutrons in the nucleus; for example, ordinary chlorine is a mixture of isotopes having atomic weights of 35 and 37, and the natural mixture has an atomic weight of about 35.453. Many of the elements similarly exist as mixtures of isotopes, and a great many new isotopes have been produced in the operation of nuclear devices such as the cyclotron. There are 275 isotopes of the 81 stable elements, in addition to more than 800 radioactive isotopes. 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. Recurrence interval, also referred to as return period, is the average time, usually expressed in years, between occurrences of hydrologic events of a specified type (such as exceedances of a specified high flow or non-exceedance of a specified low flow). The terms “return period” and “recurrence interval” do not imply regular cyclic occurrence. The actual times between occurrences vary randomly, with most of the times being less than the average and a few being substantially greater than the average. For example, the 100-year flood is the flow rate that is exceeded by the annual maximum peak flow at intervals whose average length is 100 years (that is, once in 100 years, on average); almost two-thirds of all exceedances of the 100-year flood occur less than 100 years after the previous exceedance, half occur less than 70 years after the previous exceedance, and about one-eighth occur more than 200 years after the previous exceedance. Similarly, the 7-day 10-year low flow (7Q10) is the flow rate below which the annual minimum 7-day-mean flow dips at intervals whose average length is 10 years (that is, once in 10 years, on average); almost two-thirds of the non-exceedances of the 7Q10 occur less than 10 years after the previous non-exceedance, half occur less than 7 years after, and about one-eighth occur more than 20 years after the previous non-exceedance. The recurrence interval for annual events is the reciprocal of the annual probability of occurrence. Thus, the 100-year flood has a 1-percent chance of being exceeded by the maximum peak flow in any year, and there is a 10-percent chance in any year that the annual minimum 7-day-mean flow will be less than the 7Q10. Replicate samples are a group of samples collected in a manner such that the samples are thought to be essentially identical in composition. River mile is the distance of a point on a river measured in miles from the river’s mouth along the low-water channel. 38 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 River mileage is the linear distance along the meandering path of a stream channel determined in accordance with Bulletin No. 14 (October 1968) of the Water Resources Council. Runoff in inches (IN., in.) is the depth, in inches, to which the drainage area would be covered if all the runoff for a given time period were uniformly distributed on it. Sea level refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a geodetic datum derived from a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level Datum of 1929. See: http://www.co-ops.nos.noaa.gov/ glossary/gloss_n.html#NGVD Sediment is solid material that is transported by, suspended in, or deposited from water. It originates mostly from disintegrated rocks; it also 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 or very close to the bed. In this report, bed load is considered to consist of particles in transit from the bed to an elevation equal to the top of the bed-load sampler nozzle (usually within 0.25 ft of the streambed). Bed-load discharge (tons per day) is the quantity of sediment moving as bed load, reported as dry weight, that passes a cross section in a given time. Suspended sediment is the sediment that is maintained in suspension by the upward components of turbulent currents or that exists in suspension as a colloid. 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). The entire sample is used for the analysis. Mean concentration of suspended sediment is the time-weighted concentration of suspended sediment passing a stream section during a 24-hour day. Suspended-sediment discharge (tons/day) is the quantity of sediment moving in suspension, reported as dry weight, that passes a cross section in a given time. It is calculated in units of tons per day as follows: concentration (mg/ L) x discharge (ft3/s) x 0.0027. Suspended-sediment load is a term that refers to material in suspension. The term needs to be qualified, such as “annual suspended-sediment load” or “sand-size suspended-sediment load,” and so on. It is not synonymous with either suspended-sediment 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, reported as dry weight, that passes a cross section in a given time. Total sediment load or total load is a term that refers to the total sediment (bed load plus suspended-sediment load) that is in transport. The term needs to be qualified, such as “annual suspended-sediment load” or “sand-size suspended-sediment load,” and so on. It is not synonymous with total sediment discharge. Seven-day 10-year low flow (7Q10, 7Q10) is the minimum flow averaged over 7 consecutive days that is expected to occur on average, once in any 10-year period. The 7Q10 has a 10-percent chance of occurring in any given year. 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 electrical 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 from 55 to 75 percent of the specific conductance (in microsiemens). 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. 39 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Stable isotope ratio (per MILL/MIL) is a unit expressing the ratio of the abundance of two radioactive isotopes. Isotope ratios are used in hydrologic studies to determine the age or source of specific waters, to evaluate mixing of different waters, as an aid in determining reaction rates, and other chemical or hydrologic processes. Stage: See “Gage height.” Stage-discharge relation is the relation between the water-surface elevation, termed stage (gage height), and the volume of water flowing in a channel per unit time. 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. 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 collection. Natural substrate refers to any naturally occurring immersed or submersed solid surface, such as a rock or tree, upon which an organism lives. Surface area of a lake or impoundment is that area encompassed by the boundary of the lake or impoundment as shown on USGS topographic maps, or on other available maps or photographs. The computed surface areas reflect the water levels of the lakes or impoundments at the times when the information for the maps or photographs was obtained. Surficial bed material is the top 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 undissolved material 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 suspended-sediment sample that is retained on a 0.45-micrometer 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 particulate 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 part of a representative suspended-sediment sample that is retained on a 0.45-micrometer membrane filter. This term is used only when the analytical procedure assures measurement of at least 95 percent of the constituent determined. 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. Synoptic Studies are short-term investigations of specific water-quality conditions during selected seasonal or hydrologic periods to provide improved spatial resolution for critical water-quality conditions. For the period and conditions sampled, they assess the spatial distribution of selected water-quality conditions in relation to causative factors, such as land use and contaminant sources. 40 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 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 Arthropoda ClassI insecta Order Ephemeroptera Family Ephemeridae Genus Hexagenia Species Hexagenia limbata 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 is 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. Tons per day (T/DAY, tons/d) is the rate representing a mass of 1 ton of a constituent in streamflow passing a cross section in 1 day. It is equivalent to 2,000 pounds per day, or 0.9072 metric tons per day. Total is the total amount of a given constituent in a representative 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 suspended-sediment mixture and that the analytical method determined all of the constituent in the sample.) Total discharge is the quantity of a given constituent, measured as dry mass or volume, that passes a stream cross section per unit of time. When referring to constituents other than water, this term needs to be qualified, such as “total sediment discharge,” “total chloride discharge,” and so on. Total in bottom material is the total amount of a given constituent in a representative sample of bottom material. 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 judge when the results should be reported as “total in bottom material.” Total length (fish) is the straight-line distance from the anterior point of a fish specimen’s snout, with the mouth closed, to the posterior end of the caudal (tail) fin, with the lobes of the caudal fin squeezed together. Total load refers to all of a constituent in transport. When referring to sediment, it includes suspended load plus bed load. Total recoverable is the amount of a given constituent that is in solution after a representative 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 particulate 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. Turbidity is a measurement of the collective optical properties of a water sample that cause light to be scattered and absorbed rather than transmitted in straight lines; the higher the intensity of scattered light, the higher the turbidity. Turbidity is expressed in nephelometric turbidity units (NTU) or Formazin turbidity units (FTU) depending on the method and equipment used. Volatile organic compounds (VOC’s) are organic compounds that can be isolated from the water phase of a sample by purging the water sample with inert gas, such as helium, and subsequently analyzed by gas chromatography. Many VOC’s are manmade chemicals that are used and produced in the manufacture of paints, adhesives, petroleum products, pharmaceuticals, and refrigerants. They are often components of fuels, solvents, hydraulic fluids, paint thinners, and dry cleaning agents commonly used in urban settings. VOC contamination of drinking-water supplies is a human health concern because many are toxic and are known or suspected human carcinogens (U.S. Environmental Protection Agency, 1996).WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 41 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1999 Water level is the water-surface elevation or stage of the free surface of a body of water above or below any datum (see “Gage height”), or the surface of water standing in a well, usually indicative of the position of the water table or other potentiometric surface. Water table is the surface of a ground-water body at which the water is at atmospheric pressure. Water-table aquifer is an unconfined aquifer within which is found the water table. Water year in U.S. 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, 1999, is called the “1999 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. Well is an excavation (pit, hole, tunnel), generally cylindrical in form and often walled in, drilled, dug, driven, bored, or jetted into the ground to such a depth as to penetrate water-yielding geologic material and allow the water to flow or to be pumped to the surface. Wet weight refers to the weight of animal tissue or other substance including its contained water. WSP is used as an abbreviation for “Water-Supply Paper” in reference to previously published report 42 TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS OF THE U.S. GEOLOGICAL SURVEY The U.S.G.S. publishes a series of manuals describing procedures for planning and conducting specialized work in water-resources investi- gations. 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.G.S., 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 made in the form of a 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 mention the “U.S. Geological Survey Techniques of Water-Resources Investigations.” Book 1. Collection of Water Data by Direct Measurement Section D. Water Quality 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, chap. D1. 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, chap. D2. 1976. 24 pages. Book 2. Collection of Environmental Data Section D. Surface Geophysical Methods 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, chap. D1. 1974. 116 pages. 2-D2. Application of seismic-refraction techniques to hydrologic studies, by F.P. Haeni: USGS–TWRI book 2, chap. D2. 1988. 86 pages. Section E. Subsurface Geophysical Methods 2-E1. Application of borehole geophysics to water-resources investigations, by W.S. Keys and L.M. MacCary: USGS– TWRI book 2, chap. E1. 1971. 126 pages. 2-E2. Borehole geophysics applied to ground-water investigations, by W.S. Keys: USGS–TWRI book 2, chap. E2. 1990. 150 pages. Section F. Drilling and Sampling Methods 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, chap. F1. 1989. 97 pages. Book 3. Applications of Hydraulics Section A. Surface-Water Techniques 3-A1. General ﬁeld and ofﬁce procedures for indirect discharge measurements, by M.A. Benson and Tate Dalrymple: USGS–TWRI book 3, chap. A1. 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, chap. A2. 1967. 12 pages. 3-A3. Measurement of peak discharge at culverts by indirect methods, by G.L. Bodhaine: USGS–TWRI book 3, chap. A3. 1968. 60 pages. 3-A4. Measurement of peak discharge at width contractions by indirect methods, by H.F. Matthai: USGS-TWRI book 3, chap. A4. 1967. 44 pages. 3-A5. Measurement of peak discharge at dams by indirect methods, by Harry Hulsing: USGS–TWRI book 3. chap. A5. 1967. 29 pages. 3-A6. General procedure for gaging streams, by R.W. Carter and Jacob Davidian: USGS–TWRI book 3, chap. A6. 1968. 13 pages. 3-A7. Stage measurement at gaging stations, by T.J. Buchanan and W.P. Somers: USGS–TWRI book 3, chap. A7. 1968. 28 pages. 3-A8. Discharge measurements at gaging stations, by T.J. Buchanan and W.P. Somers: USGS–TWRI book 3, chap. A8. 1969. 65 pages. 43 TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS OF THE U.S. GEOLOGICAL SURVEY 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, chap. A9. 1989. 27 pages. 3-Al0. Discharge ratings at gaging stations, by E.J. Kennedy: USGS–TWRI book 3, chap. A10. 1984. 59 pages. 3-A11. Measurement of discharge by the moving-boat method, by G.F. Smoot and C.E. Novak: USGS–TWRI book 3, chap. A11. 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, chap. A12. 1986. 34 pages. 3-A13. Computation of continuous records of streamﬂow, by E.J. Kennedy: USGS–TWRI book 3, chap. A13. 1983. 53 pages. 3-A14. Use of ﬂumes in measuring discharge, by F.A. Kilpatrick and V.R. Schneider: USGS–TWRI book 3, chap. A14. 1983. 46 pages. 3-A15. Computation of water-surface proﬁles in open channels, by Jacob Davidian: USGS–TWRI book 3, chap. A15. 1984. 48 pages. 3-A16. Measurement of discharge using tracers, by F.A. Kilpatrick and E.D. Cobb: USGS–TWRI book 3, chap. A16. 1985. 52 pages. 3-A17. Acoustic velocity meter systems, by Antonius Laenen: USGS–TWRI book 3, chap. 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, chap. A18. 1989. 52 pages. 3-A19. Levels at streamﬂow gaging stations, by E.J. Kennedy: USGS–TWRI book 3, chap. A19. 1990. 31 pages. 3-A20. Simulation of soluable waste transport and buildup in surface waters using tracers, by F.A. Kilpatrick: USGS–TWRI book 3, chap. A20. 1993. 38 pages. 3-A21 Stream-gaging cableways, by C. Russell Wagner: USGS–TWRI book 3, chap. A21. 1995. 56 pages. Section B. Ground-Water Techniques 3-B1. Aquifer-test design, observation, and data analysis, by R.W. Stallman: USGS–TWRI book 3, chap. B1. 1971. 26 pages. 3-B2. Introduction to ground-water hydraulics, a programed text for self-instruction, by G.D. Bennett: USGS–TWRI book 3, chap. 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, chap. B3. 1980. 106 pages. 3-B4. Regression modeling of ground-water ﬂow, by R.L. Cooley and R.L. Naff: USGS–TWRI book 3, chap. B4. 1990. 232 pages. 3-B4. Supplement 1. 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, chap. 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, chap. 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, chap. 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, chap. B7. 1992. 190 pages. Section C. Sedimentation and Erosion Techniques 3-C1. Fluvial sediment concepts, by H.P. Guy: USGS–TWRI book 3, chap. 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, chap. C2. 1970. 59 pages. 3-C3. Computation of ﬂuvial-sediment discharge, by George Porterﬁeld: USGS–TWRI book 3, chap. C3. 1972. 66 pages. 44 TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS OF THE U.S. GEOLOGICAL SURVEY Book 4. Hydrologic Analysis and Interpretation Section A. Statistical Analysis 4-A1. Some statistical tools in hydrology, by H.C. Riggs: USGS–TWRI book 4, chap. A1. 1968. 39 pages. 4-A2. Frequency curves, by H.C. Riggs: USGS–TWRI book 4, chap. A2. 1968. 15 pages. Section B. Surface Water 4-B1. Low-ﬂow investigations, by H.C. Riggs: USGS–TWRI book 4, chap. B1. 1972. 18 pages. 4-B2. Storage analyses for water supply, by H.C. Riggs and C.H. Hardison: USGS–TWRI book 4, chap. B2. 1973. 20 pages. 4-B3. Regional analyses of streamﬂow characteristics, by H.C. Riggs: USGS–TWRI book 4, chap. B3. 1973. 15 pages. Section D. Interrelated Phases of the Hydrologic Cycle 4-D1. Computation of rate and volume of stream depletion by wells, by C.T. Jenkins: USGS–TWRI book 4, chap. D1. 1970. 17 pages. Book 5. Laboratory Analysis Section A. Water Analysis 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, chap. A1. 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, chap. 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, chap. 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, chap. 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, chap. 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, chap. A6. 1982. 181 pages. Section C. Sediment Analysis 5-C1. Laboratory theory and methods for sediment analysis, by H.P. Guy: USGS–TWRI book 5, chap. C1. 1969. 58 pages. Book 6. Modeling Techniques Section A. Ground Water 6-A1. A modular three-dimensional ﬁnite-difference ground-water ﬂow model, by M.G. McDonald and A.W. Harbaugh: USGS–TWRI book 6, chap. A1. 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, chap. 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, chap. 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, chap. 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, chap. 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. 1996. 125 pages. 45 TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS OF THE U.S. GEOLOGICAL SURVEY Book 7. Automated Data Processing and Computations Section C. Computer Programs 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, chap. C1. 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, chap. 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, chap. C3. 1981. 110 pages. Book 8. Instrumentation Section A. Instruments for Measurement of Water Level 8-A1. Methods of measuring water levels in deep wells, by M.S. Garber and F.C. Koopman: USGS–TWRI book 8, chap. A1. 1968. 23 pages. 8-A2. Installation and service manual for U.S. Geological Survey manometers, by J.D. Craig: USGS–TWRI book 8, chap. A2. 1983. 57 pages. Section B. Instruments for Measurement of Discharge 8-B2. Calibration and maintenance of vertical-axis type current meters, by G.F. Smoot and C.E. Novak: USGS–TWRI book 8, chap. B2. 1968. 15 pages. Book 9. Handbooks for Water-Resources Investigations Section A. National Field Manual for the Collection of Water-Quality Data 9-A1. National Field Manual for the Collection of Water-Quality Data: Preparations for Water Sampling, by F.D. Wilde, D.B. Radtke, Jacob Gibs, and R.T. Iwatsubo: USGS–TWRI book 9, chap. A1. 1998. 47 p. 9-A2. National Field Manual for the Collection of Water-Quality Data: Selection of Equipment for Water Sampling, edited by F.D. Wilde, D.B. Radtke, Jacob Gibs, and R.T. Iwatsubo: USGS–TWRI book 9, chap. A2. 1998. 94 p. 9-A3. National Field Manual for the Collection of Water-Quality Data: Cleaning of Equipment for Water Sampling, edited by F.D. Wilde, D.B. Radtke, Jacob Gibs, and R.T. Iwatsubo: USGS–TWRI book 9, chap. A3. 1998. 75 p. 9-A4. National Field Manual for the Collection of Water-Quality Data: Collection of Water Samples, edited by F.D. Wilde, D.B. Radtke, Jacob Gibs, and R.T. Iwatsubo: USGS–TWRI book 9, chap. A4. 1999. 156 p. 9-A5. National Field Manual for the Collection of Water-Quality Data: Processing of Water Samples, edited by F.D. Wilde, D.B. Radtke, Jacob Gibs, and R.T. Iwatsubo: USGS–TWRI book 9, chap. A5. 1999, 149 p. 9-A6. National Field Manual for the Collection of Water-Quality Data: Field Measurements, edited by F.D. Wilde and D.B. Radtke: USGS–TWRI book 9, chap. A6. 1998. Variously paginated. 9-A7. National Field Manual for the Collection of Water-Quality Data: Biological Indicators,edited by D.N. Myers and F.D. Wilde: USGS–TWRI book 9, chap. A7. 1997 and 1999. Variously paginated. 9-A8. National Field Manual for the Collection of Water-Quality Data: Bottom-material samples, by D.B. Radtke: USGS– TWRI book 9, chap. A8. 1998. 48 pages. 9-A9. National Field Manual for the Collection of Water-Quality Data: Safety in Field Activities, by S.L. Lane and R.G. Fay: USGS–TWRI book 9, chap. A9. 1998. 60 pages. 46 THIS PAGE WAS LEFT BLANK INTENTIONALLY Surface and Quality-of-Water Records for Puerto Rico 47 48 THIS PAGE WAS LEFT BLANK INTENTIONALLY Canal Principal de los Cedros de Diversión Quebrada Río Río Guajataca Guajataca Lago de Guajataca 0108 QUALITY-OF-WATER STATION AND NUMBER 0105 0105 165 EXPLANATION WELL AND WELL NUMBER LAKE-ELEVATION STATION AND NUMBER DRAINAGE BASIN BOUNDARY TOWN OR CITY SURFACE-WATER STATION AND NUMBER CHANNEL FLOW DIRECTION Figure 11. Río Guajataca basin. 49 AGUADILLA ISABELA QUEBRADILLAS CAMUY ATLANTIC OCEAN Basin area PUERTO RICO SAN SEBASTIÁN MOCA LARES 0114 202 165 1001 0110 0108 010790 010720 0105 0 0 1 1 2 2 3 3 4 4 5 MILES 5 KILOMETERS 50 RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR LOCATION.--Lat 18°18'01", long 66°52'24", Hydrologic Unit 21010001 at bridge on Highway 111, 0.1 mi (0.2 km) upstream from Quebrada Anón, and 0.4 mi (0.6 km) east of Lares. DRAINAGE AREA.--3.16 mi2 (8.18 km2). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--February 1959 to February 1962 (annual low-flow measurements only), January 1963 to April 1969 (monthly measurements only), May 1969 to December 1970 (February to May 1971 and March 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 34 19 6.8 2.7 2.6 3.0 7.1 5.0 37 9.7 4.3 3.9 2 23 15 17 2.7 2.5 23 16 4.1 22 9.8 4.1 18 3 18 20 13 2.5 2.1 7.4 10 3.6 55 9.1 5.9 19 4 17 e32 7.1 2.5 2.4 3.0 6.4 30 22 9.5 6.0 16 5 15 16 6.0 2.3 2.4 2.5 5.0 11 15 21 15 32 6 14 e13 5.7 2.3 2.4 2.4 4.6 64 14 10 5.3 71 7 15 39 5.3 2.1 2.3 3.0 4.3 64 15 7.7 23 24 8 36 17 5.0 2.1 2.2 2.7 4.6 36 28 13 9.1 29 9 39 16 5.0 2.1 2.3 3.4 4.1 17 31 8.3 5.1 41 10 34 17 5.0 2.3 2.3 4.7 7.3 12 60 7.7 5.1 18 11 15 e14 4.6 2.9 2.6 4.4 4.8 10 74 11 17 34 12 13 e12 5.1 2.3 2.7 2.6 3.1 8.9 31 6.5 8.1 16 13 10 11 4.0 4.6 2.5 2.4 3.0 7.9 22 6.1 5.7 15 14 9.4 10 4.1 3.1 2.4 2.8 2.7 7.1 20 5.7 12 11 15 29 13 4.0 16 2.5 2.6 2.6 6.7 17 5.6 6.2 13 16 12 22 3.8 11 2.5 2.9 2.6 6.2 16 7.2 4.4 10 17 9.5 11 3.3 4.3 e2.7 2.5 2.6 26 13 5.5 56 8.9 18 39 9.1 3.2 2.6 e2.1 4.7 2.4 8.1 22 5.0 9.0 8.4 19 14 8.6 3.2 2.6 e2.3 37 2.5 7.4 25 4.6 7.3 8.0 20 10 8.1 4.9 2.9 e2.6 6.1 2.4 6.6 23 4.6 5.3 7.3 21 9.2 7.4 4.1 11 e2.5 18 11 14 14 17 5.8 6.9 22 10 7.2 3.7 5.0 e2.3 17 9.1 24 37 11 16 6.7 23 10 6.9 4.1 2.4 e2.0 6.5 16 15 17 14 8.2 6.4 24 16 6.7 3.8 2.2 e1.8 36 40 11 13 7.3 5.7 16 25 26 6.7 3.3 2.3 e2.0 52 14 11 12 5.2 39 26 26 30 6.2 3.2 2.9 e47 16 5.5 11 11 4.9 13 18 27 e20 11 3.3 3.2 6.2 8.7 7.7 45 10 4.6 5.5 22 28 19 7.6 3.1 4.6 4.7 16 4.9 121 9.4 4.4 4.3 14 29 37 5.8 3.0 2.3 --- 15 29 19 8.8 4.0 3.8 12 30 27 5.8 2.8 2.3 --- 13 9.5 108 9.0 4.5 6.5 11 31 22 --- 2.8 2.2 --- 8.1 --- 66 --- 3.7 7.2 --- TOTAL 632.1 394.1 153.3 116.3 116.9 329.4 244.8 786.6 703.2 248.2 328.9 542.5 MEAN 20.4 13.1 4.95 3.75 4.18 10.6 8.16 25.4 23.4 8.01 10.6 18.1 MAX 39 39 17 16 47 52 40 121 74 21 56 71 MIN 9.2 5.8 2.8 2.1 1.8 2.4 2.4 3.6 8.8 3.7 3.8 3.9 AC-FT 1250 782 304 231 232 653 486 1560 1390 492 652 1080 CFSM 6.45 4.16 1.56 1.19 1.32 3.36 2.58 8.03 7.42 2.53 3.36 5.72 IN. 7.44 4.64 1.80 1.37 1.38 3.88 2.88 9.26 8.28 2.92 3.87 6.39 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1969 - 1999, BY WATER YEAR (WY) MEAN 16.8 8.49 3.81 3.39 2.78 2.84 3.60 10.4 8.61 4.57 6.65 15.1 MAX 33.7 16.7 7.31 8.91 7.21 10.6 8.16 25.4 23.4 9.85 11.1 45.2 (WY) 1991 1971 1971 1997 1996 1999 1999 1999 1999 1969 1996 1998 MIN 8.52 2.42 1.35 .66 .93 .92 1.09 2.37 1.70 1.73 3.34 5.95 (WY) 1995 1998 1991 1991 1992 1994 1994 1997 1997 1997 1970 1993 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1969 - 1999 ANNUAL TOTAL 3569.47 4596.3 ANNUAL MEAN 9.78 12.6 7.18 HIGHEST ANNUAL MEAN 12.6 1999 LOWEST ANNUAL MEAN 4.13 1994 HIGHEST DAILY MEAN 505 Sep 22 121 May 28 505 Sep 22 1998 LOWEST DAILY MEAN .55 Apr 6 1.8 Feb 24 .47 Jan 13 1991 ANNUAL SEVEN-DAY MINIMUM .68 Apr 9 2.2 Feb 19 .51 Jan 9 1991 INSTANTANEOUS PEAK FLOW 2790 May 28 5300 Oct 7 1990 INSTANTANEOUS PEAK STAGE 17.16 May 28 21.30 Oct 7 1990 ANNUAL RUNOFF (AC-FT) 7080 9120 5200 ANNUAL RUNOFF (CFSM) 3.09 3.99 2.27 ANNUAL RUNOFF (INCHES) 42.02 54.11 30.89 10 PERCENT EXCEEDS 22 29 16 50 PERCENT EXCEEDS 3.2 7.7 3.6 90 PERCENT EXCEEDS .84 2.5 .99 e Estimated 51 RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 1,000 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 52 RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°18'01", long 66°52'24", at bridge on Highway 111 (km 32.9), 0.1 mi (0.2 km) upstream from Quebrada Anón, and 0.4 mi (0.6 km) northeast of Lares plaza. DRAINAGE AREA.--3.16 mi2 (8.18 km2). PERIOD OF RECORD.--Water years 1958-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 02... 1050 14 219 7.6 24.0 8.0 7.7 94 <10 K1100 690 FEB 23... 1315 1.8 232 7.9 23.5 3.9 9.6 117 <10 2300 260 MAY 18... 1145 7.8 225 7.5 23.5 8.3 7.3 90 <10 K1600 1600 AUG 16... 1355 3.5 210 7.6 27.0 1.8 7.3 95 <10 2100 620 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 02... 82 24 5.3 10 .5 2.5 77 <1.0 6.8 11 FEB 23... -- -- -- -- -- -- 89 -- -- -- MAY 18... 84 25 5.4 11 .5 2.8 79 <1.0 8.7 11 AUG 16... 85 24 5.8 12 .6 2.5 89 -- 4.7 13 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 02... <.10 29 135 5.30 12 2.39 .011 2.40 .010 -- FEB 23... -- -- -- -- 7 -- <.010 1.10 .030 -- MAY 18... <.10 31 142 2.98 8 -- <.010 1.90 .020 -- AUG 16... <.10 32 148 1.40 6 1.89 .010 1.90 .030 .18 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 02... <.20 -- -- .040 <1 <100 20 <1 <1 <10 FEB 23... <.20 -- -- .060 -- -- -- -- -- -- MAY 18... <.20 -- -- E.050 1 30 30 <1 <1 <12 AUG 16... .21 2.1 9.3 .060 -- -- -- -- -- -- 53 RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 02... 330 <1 36 <.10 <1 <1 <10 <.010 <4 <.02 FEB 23... -- -- -- -- -- -- -- -- -- -- MAY 18... 320 <1 37 <.10 4 <1 <40 <.010 <4 <.02 AUG 16... -- -- -- -- -- -- -- -- -- -- 54 RIO GUAJATACA BASIN 50010800 LAGO GUAJATACA AT DAMSITE NEAR QUEBRADILLAS, PR 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 de Padua and 2.8 mi (4.5 km) from Escuela Segunda Unidad Baldorioty de Castro. DRAINAGE AREA.--24.6 mi2 (63.71 km2). 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) high, 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 length 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. New capacity table based on U.S. Geological Survey Water-Resources Investigations Report 00-4044,January 1999. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 648.3 ft (197.60 m), Sept. 23, 1998; minimum elevation, 608.07 ft (185.34 m) May 17, 1998. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 646.04 ft (196.91 m), Oct. 31; minimum elevation, 636.37 ft (193.96 m), Feb. 25. Capacity Table (based on data from U.S. Geological Survey Water-Resources Investigations Report 00-4044,Puerto Rico-1999) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 557 0 616 13,393 577 916 636 26,332 597 5,253 646 34,277 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 645.64 645.54 642.68 641.06 639.73 637.97 641.09 642.56 644.23 641.02 639.95 A 2 645.12 644.90 643.32 640.94 639.61 638.53 641.25 642.57 644.04 640.90 639.89 A 3 644.44 644.21 644.26 640.83 639.47 638.82 641.37 642.55 644.85 640.78 639.85 A 4 643.72 643.70 643.94 640.70 639.34 638.76 641.42 642.57 645.21 640.65 639.80 A 5 642.95 643.20 643.50 640.58 639.19 638.68 641.46 642.74 645.21 640.69 639.76 A 6 642.31 642.88 643.02 640.46 639.06 A 641.50 643.01 645.06 640.59 639.70 A 7 641.96 642.98 642.84 640.34 638.92 A 641.54 643.54 645.03 640.67 639.66 A 8 642.00 643.00 642.80 640.21 638.79 638.30 641.57 644.00 644.70 640.64 639.62 A 9 642.17 643.00 642.77 640.09 638.64 A A 643.92 645.31 640.61 639.55 642.04 10 642.52 643.08 642.69 640.00 638.53 A A 643.64 645.46 640.55 639.49 641.79 11 642.76 643.17 642.64 639.89 638.40 A A 643.32 645.42 640.54 639.44 641.64 12 642.83 643.36 642.58 639.78 638.25 638.18 A 642.96 645.17 640.52 639.38 641.37 13 643.42 643.57 642.52 640.04 638.11 638.20 641.34 642.78 644.81 640.48 639.34 641.20 14 643.53 643.34 642.46 639.98 637.98 638.22 641.32 642.76 644.40 640.42 639.38 641.19 15 643.73 643.37 642.53 640.69 637.83 638.23 641.29 642.76 643.99 640.37 639.35 641.17 16 643.50 643.69 642.46 641.10 637.67 638.26 641.26 642.74 643.55 640.40 639.28 641.15 17 643.12 643.59 642.38 641.14 637.53 638.28 641.23 642.87 643.13 640.37 639.50 641.10 18 642.91 643.35 642.29 641.06 637.38 638.29 641.19 642.92 642.72 640.33 639.52 641.07 19 642.51 643.17 642.24 641.01 637.25 638.45 641.16 642.91 642.33 640.27 639.59 641.03 20 642.36 643.12 642.20 640.92 637.10 638.54 641.13 642.90 642.23 640.22 639.62 640.99 21 642.36 643.05 642.15 640.87 636.95 638.63 641.10 642.91 642.12 640.20 639.67 640.95 22 642.41 642.96 642.06 640.78 636.79 638.80 641.06 642.99 642.26 640.29 639.67 640.93 23 642.73 642.92 641.98 640.68 636.63 639.00 641.05 643.09 642.28 640.32 A 640.89 24 642.99 642.86 641.91 640.55 636.47 639.35 641.14 643.14 642.13 640.29 A 640.87 25 643.30 642.79 641.81 640.42 636.59 640.10 641.13 643.16 641.91 640.26 A 640.88 26 643.57 642.74 641.70 640.32 637.73 640.38 641.10 643.20 641.66 640.24 A 640.88 27 643.56 642.72 641.61 640.20 637.95 640.47 641.08 643.54 641.48 640.21 A 640.88 28 644.82 642.68 641.53 640.16 638.01 640.69 641.05 643.95 641.37 640.14 A 640.86 29 645.47 642.64 641.42 640.06 --- 640.84 642.05 643.96 641.25 640.07 A 641.00 30 645.84 642.64 641.31 639.93 --- 640.97 642.48 644.13 641.13 640.05 A 641.05 31 645.94 --- 641.19 639.80 --- 641.04 --- 644.23 --- 640.00 A --- MAX 645.94 645.54 644.26 641.14 639.73 --- --- 644.23 645.46 641.02 --- --- MIN 641.96 642.64 641.19 639.78 636.47 --- --- 642.55 641.13 640.00 --- --- A No gage-height record 55 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 1998 TO SEPTEMBER 1999 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, INST. CIFIC WHOLE SOLVED CHEM- FECAL, CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) NOV 16... 1215 65 327 7.2 25.5 1.0 .3 4 <10 100 MAR 01... 1445 75 342 7.6 24.5 2.4 2.2 27 14 23 MAY 25... 1430 70 294 7.3 24.5 1.7 .7 8 <10 K21 AUG 16... 1615 65 286 7.8 26.5 6.4 1.0 13 <10 K4 ANC STREP- HARD- MAGNE- SODIUM POTAS- WATER TOCOCCI NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE FECAL, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- (COLS. (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED DATE PER AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L 100 ML) CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) (31679) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) NOV 16... 80 150 55 3.3 5.3 .2 2.4 150 <1.0 7.0 MAR 01... 22 -- -- -- -- -- -- 150 -- -- MAY 25... K10 140 49 3.3 5.0 .2 2.2 130 <1.0 8.0 AUG 16... <2 140 50 3.5 5.3 .2 2.2 136 -- 7.1 SOLIDS, RESIDUE CHLO- FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- RIDE, RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, DIS- DIS- SOLVED TUENTS, SOLVED DEG. C, NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL DATE (MG/L (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L AS CL) AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) (00940) (00950) (00955) (70301) (70302) (00530) (00615) (00630) (00610) (00605) NOV 16... 8.2 <.10 7.3 179 31.4 4 <.010 .220 .110 .14 MAR 01... -- -- -- -- -- 3 <.010 .080 .060 .20 MAY 25... 7.7 <.10 5.9 159 30.0 <1 <.010 .140 .020 -- AUG 16... 7.3 <.10 7.1 164 28.8 1 <.010 .020 .070 .22 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 16... .25 .47 2.1 .020 1 <100 30 <1 <1 <10 MAR 01... .26 .34 1.5 <.020 -- -- -- -- -- -- MAY 25... E.32 -- -- E.020 1 20 E20 <1 <1 <12 AUG 16... .29 .31 1.4 <.020 -- -- -- -- -- -- 56 RIO GUAJATACA BASIN 50011000 CANAL PRINCIPAL DE DIVERSIONES AT LAGO DE GUAJATACA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 16... 50 <1 100 <.10 <1 <1 <10 <.010 <4 .02 MAR 01... -- -- -- -- -- -- -- -- -- -- MAY 25... 40 <1 51 <.10 <1 <1 <40 <.010 <4 .02 AUG 16... -- -- -- -- -- -- -- -- -- -- 57 RIO GUAJATACA BASIN 50011400 RIO GUAJATACA ABOVE MOUTH NEAR QUEBRADILLAS, PR. 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) upstream 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 1998 TO SEPTEMBER 1999 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, INST. CIFIC WHOLE SOLVED CHEM- FECAL, CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) NOV 10... 1215 57 385 7.8 25.5 4.6 7.2 87 <10 2300 MAR 03... 0715 35 406 7.4 23.0 2.1 6.3 73 <10 K73 MAY 27... 1045 21 433 7.6 25.5 8.0 6.9 85 <10 K60 AUG 18... 0950 38 392 8.1 25.3 -- 6.8 82 <10 80 ANC STREP- HARD- MAGNE- SODIUM POTAS- WATER TOCOCCI NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE FECAL, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- (COLS. (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED DATE PER AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L 100 ML) CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) (31679) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) NOV 10... 2200 180 65 4.1 7.8 .3 1.7 180 <1.0 7.1 MAR 03... 300 -- -- -- -- -- -- 180 -- -- MAY 27... 140 210 72 6.8 14 .4 1.3 200 <1.0 7.9 AUG 18... 980 170 61 4.9 9.7 .3 1.6 170 -- 5.5 SOLIDS, RESIDUE CHLO- FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- RIDE, RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, DIS- DIS- SOLVED TUENTS, SOLVED DEG. C, NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL DATE (MG/L (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L AS CL) AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) (00940) (00950) (00955) (70301) (70302) (00530) (00615) (00630) (00610) (00605) NOV 10... 14 <.10 6.2 214 33.0 4 <.010 1.10 <.010 -- MAR 03... -- -- -- -- -- <1 <.010 1.60 .010 -- MAY 27... 23 <.10 7.3 252 14.6 <1 <.010 1.80 .020 -- AUG 18... 16 <.10 6.7 207 21.4 5 <.010 .910 .020 .19 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 10... <.20 -- -- <.020 <1 <100 10 <1 1 <10 MAR 03... <.20 -- -- <.020 -- -- -- -- -- -- MAY 27... <.20 -- -- <.020 <1 10 40 <1 1 <12 AUG 18... .21 1.1 5.0 <.020 -- -- -- -- -- -- 58 RIO GUAJATACA BASIN 50011400 RIO GUAJATACA ABOVE MOUTH NEAR QUEBRADILLAS, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 10... 140 <1 37 <.10 <1 <1 <10 <.010 <4 <.02 MAR 03... -- -- -- -- -- -- -- -- -- -- MAY 27... 50 <1 12 <.10 <1 <1 <40 <.010 <4 .04 AUG 18... -- -- -- -- -- -- -- -- -- -- Río Río Río Piedras Río Caño Tiburones Camuy River Underground A n g e l e s C r i m i n a l e s CAÑO TIBURONES FLOW DIRECTION 0148 1027 EXPLANATION WELL AND WELL NUMBER DRAINAGE BASIN BOUNDARY TOWN OR CITY SURFACE-WATER STATION AND NUMBER Figure 12. Río Camuy basin. 59 QUEBRADILLAS CAMUY HATILLO ARECIBO ATLANTIC OCEAN LARES UTUADO 0148 Basin area PUERTO RICO 0 0 1 1 2 2 3 3 4 4 5 MILES 5 KILOMETERS 1027 1026 60 RIO CAMUY BASIN 50014800 RIO CAMUY NEAR BAYANEY, PR LOCATION.--Lat 18°23'48", long 66°49'04", Hydrologic 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e176 675 e192 64 61 74 73 101 492 102 60 86 2 e158 465 e328 63 63 124 118 64 367 102 60 116 3 e146 472 e305 63 55 156 133 57 343 96 68 410 4 e134 355 e154 62 53 69 91 138 479 92 70 265 5 e126 233 e130 61 52 59 69 134 282 94 149 166 6 e125 184 e118 62 50 56 63 411 198 92 95 481 7 e193 223 e112 61 50 54 59 366 259 84 112 240 8 e517 232 e105 60 49 50 59 499 e221 100 99 292 9 387 e167 e100 60 48 53 62 289 e887 98 66 313 10 240 e351 94 60 48 71 71 130 636 81 61 143 11 e138 e240 90 62 47 108 66 95 e418 85 119 235 12 e136 e217 86 58 50 60 56 83 e273 91 104 163 13 e137 e250 84 59 47 54 54 76 e247 e79 80 120 14 e129 e205 82 61 47 47 53 71 e351 e74 70 89 15 e138 e193 78 155 46 45 52 65 e616 e73 72 78 16 e342 e228 77 204 48 42 51 62 e491 80 61 75 17 e265 e189 75 99 45 41 50 160 e393 95 185 66 18 e189 e175 73 70 44 41 48 175 e342 72 109 62 19 e160 e173 74 64 44 90 47 80 e386 67 89 67 20 e141 e168 87 62 44 196 47 67 e289 65 109 61 21 e125 e165 89 84 43 115 46 66 e243 151 103 54 22 e140 e155 75 100 42 115 45 97 e303 184 84 51 23 119 e163 79 66 42 131 44 109 e218 147 290 48 24 116 e208 79 61 42 140 65 72 e171 103 141 55 25 242 e175 73 59 68 150 67 63 147 80 160 75 26 216 e168 71 58 203 90 52 58 135 112 187 75 27 314 e374 69 66 137 67 48 143 126 102 116 79 28 446 288 69 86 68 173 70 424 119 75 87 58 29 1250 e199 68 65 --- 178 332 e337 114 67 133 68 30 1260 e186 66 57 --- 155 278 472 108 65 107 52 31 857 --- 66 55 --- 102 --- 666 --- 63 108 --- TOTAL 9062 7476 3248 2267 1636 2906 2369 5630 9654 2871 3354 4143 MEAN 292 249 105 73.1 58.4 93.7 79.0 182 322 92.6 108 138 MAX 1260 675 328 204 203 196 332 666 887 184 290 481 MIN 116 155 66 55 42 41 44 57 108 63 60 48 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1984 - 1999, BY WATER YEAR (WY) MEAN 203 122 69.0 58.2 50.6 49.9 86.1 168 124 76.3 98.5 197 MAX 427 249 105 163 96.4 93.7 202 624 322 109 187 726 (WY) 1986 1999 1999 1997 1996 1999 1986 1986 1999 1989 1998 1998 MIN 81.6 53.4 36.5 33.1 29.1 23.7 28.0 43.2 42.7 38.8 47.9 61.8 (WY) 1988 1998 1998 1991 1998 1994 1994 1989 1997 1994 1993 1997 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1984 - 1999 ANNUAL TOTAL 61495 54616 ANNUAL MEAN 168 150 109 HIGHEST ANNUAL MEAN 179 1986 LOWEST ANNUAL MEAN 61.5 1994 HIGHEST DAILY MEAN 9010 Sep 22 1260 Oct 30 9010 Sep 22 1998 LOWEST DAILY MEAN 22 Mar 25 41 Mar 17 16 Mar 18 1994 ANNUAL SEVEN-DAY MINIMUM 23 Mar 22 43 Feb 18 17 Mar 16 1994 INSTANTANEOUS PEAK FLOW 5650 Oct 29 11600 Sep 22 1998 INSTANTANEOUS PEAK STAGE 16.88 Oct 29 21.69 Sep 22 1998 INSTANTANEOUS LOW FLOW 39 Mar 18 15 Mar 22 1994 10 PERCENT EXCEEDS 309 330 212 50 PERCENT EXCEEDS 75 95 68 90 PERCENT EXCEEDS 26 52 33 e Estimated 61 RIO CAMUY BASIN 50014800 RIO CAMUY NEAR BAYANEY, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 62 THIS PAGE WAS LEFT BLANK INTENTIONALLY Río Río Río Río Río Río Río Río Jauca Río Río Río Cidra Río Río Río Río Río Caricaboa Saliente G r a n d e Grande G r a n d e de de de J a y u y a Arecibo Arecibo Río Río Lago Caonillas Lago Pellejas Lago Adjuntas Lago Viví Lago Garzas Lago Jordan Lago Dos Bocas Caño Tiburones Tanamá Limón Limón La Venta Yunes C a o n i l l a s C a o n il las Viví Tunnel Tunnel Tunnel Tunnel Tunnel Viví Vacas Pellejas 0280 CAÑO TIBURONES FLOW DIRECTION TUNNEL FLOW DIRECTION QUALITY-OF-WATER STATION AND NUMBER 0280 0205 205 0201 EXPLANATION WELL AND WELL NUMBER LAKE-ELEVATION STATION AND NUMBER DRAINAGE BASIN BOUNDARY TOWN OR CITY SEDIMENT STATION AND NUMBER SURFACE-WATER STATION AND NUMBER Figure 13. Río Grande de Arecibo basin. 63 HATILLO ARECIBO BARCELONETA Basin area PUERTO RICO ATLANTIC OCEAN ADJUNTAS JAYUYA UTUADO FLORIDA 0 0 1 1 2 2 3 3 4 4 5 MILES 5 KILOMETERS 0284 027750 0290 027250 027090 0271 025110 026140 0250 026050 026025 0280 0205 204 1051 1055 1056 1052 1053 1054 1057 205 020050 0201 64 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 Río Vacas, 1.7 mi (2.7 km) upstream from Río Garzas, and 2.2 mi (3.5 km) southwest of Adjuntas. DRAINAGE AREA.--6.02 mi2 (15.6 km2). ELEVATION RECORDS PERIOD OF RECORD.--January 1988 to May 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 May 25, 1988 at datum 2,376.80 ft (724.449 m), May 25 to July 13, 1988 at datum 2,338.08 ft (712.647 m), July 14, 1988 to May 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. New capacity table based on U.S. Geological Survey Water-Resources Investigations Report 99-4143,September 1996. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 2,418.28 ft (737.092 m),Sept. 22, 1998; minimum elevation, 2,364.79 ft (720.788 m), Aug. 23, 1988. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 2,416.00 ft (736.40 m), Oct.08; minimum elevation, 2,405.23 ft (733.110 m), Aug. 25. Capacity Table (based on data from U.S. Geological Survey Water-Resources Investigations Report 99-4143,1996) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 2,317 0 2,376 1,419 2,336 243 2,399 2,700 2,359 794 2,415 4,143 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 2414.97 A 2414.82 A A A A A 2414.85 2414.74 2412.91 2409.20 2 2414.97 A A A A A A A 2414.75 2414.75 2412.91 2411.33 3 A A 2414.85 A A A A A 2414.73 2414.75 2410.73 2412.02 4 2414.91 2414.90 2414.85 A A A A A 2414.73 2414.75 2411.31 2412.52 5 2414.91 2414.89 2414.92 A A A A A 2414.73 2414.74 2411.55 2413.33 6 A 2414.89 A A A A A A 2414.73 2414.74 2411.78 2414.12 7 2414.97 A 2414.85 A A A A A 2414.73 2414.74 2412.00 2414.64 8 2415.14 2414.86 A A A A A A 2414.79 2414.74 2412.01 2414.91 9 A A A A A A A A 2414.79 2414.73 2412.03 2414.94 10 2414.91 A A A A A A A 2414.70 2414.73 2409.77 2414.92 11 2414.91 A A A A A A A 2414.77 2414.74 A 2414.92 12 A 2414.86 A A A A A A 2414.79 2414.74 A 2414.92 13 2414.87 A A A A A A A 2414.85 2414.74 A 2415.11 14 A A A A A A A A 2414.85 2414.73 A 2415.02 15 2414.87 A A A A A A A 2414.85 2414.73 A 2414.92 16 2414.93 A A A A A A A 2414.78 2414.73 A 2414.88 17 2414.87 2414.85 A A A A A A 2414.79 2414.73 A 2414.53 18 2414.87 A A A A A A A 2414.79 2414.73 A 2414.35 19 2414.86 2414.80 A A A A A A 2414.81 2414.71 A 2414.80 20 2414.87 2414.83 A A A A A A 2414.79 A A 2414.90 21 2414.89 2414.83 A A A A A 2414.67 2414.79 2412.80 A 2414.91 22 A 2414.82 A A A A A 2414.67 2414.79 2412.78 A 2414.45 23 2414.95 2414.81 A A A A A 2414.68 2414.79 2412.77 A 2414.81 24 A 2414.82 A A A A A 2414.68 2414.75 2412.78 2405.27 2414.70 25 2414.87 2414.80 A A A A A 2414.68 2414.73 2412.79 2405.23 2414.91 26 2414.96 A A A A A A 2414.68 2414.73 2412.80 2405.49 2414.91 27 A A A A A A A 2414.68 2414.73 2412.81 2405.85 2414.94 28 A 2414.88 A A A A A 2414.68 2414.73 2412.82 2406.13 2414.66 29 2414.93 2414.83 A A --- A A 2414.68 2414.74 2412.88 2407.77 2414.32 30 A 2414.82 A A --- A A 2414.68 2414.74 2412.89 2407.91 2413.88 31 A --- A --- --- A --- 2414.68 --- 2412.90 2408.12 --- MAX --- --- --- --- --- --- --- --- 2414.85 --- --- 2415.11 MIN --- --- --- --- --- --- --- --- 2414.70 --- --- 2409.20 A No gage-height record 65 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 mi2 (32.9 km2) this does not include 6.0 mi2 (15.6 km2) above Lago Garzas. PERIOD OF RECORD.--Water years 1969-74, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 23... 1300 55 233 7.8 25.5 9.7 7.8 100 <10 410 470 FEB 22... 1350 15 321 8.2 25.5 -- 8.2 104 <10 320 900 MAY 20... 0900 13 348 8.0 24.0 1.7 8.8 111 <10 400 K220 AUG 11... 0950 18 351 8.5 25.7 3.0 8.9 115 <10 E150 E160 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 23... 81 21 7.0 13 .6 1.8 79 <1.0 6.5 13 FEB 22... -- -- -- -- -- -- 110 -- -- -- MAY 20... 130 33 10 19 .7 1.9 120 <1.0 11 25 AUG 11... 130 34 10 18 .7 2.2 110 -- 10 23 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 23... <.10 25 134 19.9 14 -- <.010 1.20 .020 .44 FEB 22... -- -- -- -- -- 1.18 .024 1.20 .040 .52 MAY 20... <.10 32 204 7.01 1 .750 .010 .760 .040 -- AUG 11... <.10 32 196 9.30 5 .840 .020 .860 .020 -- NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 23... .46 1.7 7.3 .100 <1 <100 20 <1 1 <10 FEB 22... .56 1.8 7.8 .300 -- -- -- -- -- -- MAY 20... <.20 -- -- E.060 <1 20 30 <1 <1 <12 AUG 11... <.20 -- -- .070 -- -- -- -- -- -- 66 RIO GRANDE DE ARECIBO BASIN 50020500 RIO GRANDE DE ARECIBO NEAR ADJUNTAS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 23... 620 1 45 <.10 <1 <1 10 <.010 <4 <.02 FEB 22... -- -- -- -- -- -- -- -- -- -- MAY 20... 40 <1 24 <.10 <1 <1 <40 <.010 <4 .03 AUG 11... -- -- -- -- -- -- -- -- -- -- 67 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 Río de Caguana, and 2.5 mi (4.0 km) north of Utuado plaza. DRAINAGE AREA.--66.0 mi2 (170.9 km2) this excludes 6.0 mi2 (15.5 km2) upstream from Lago Garzas to R!o Guayanes in the Río Tallaboa basin. PERIOD OF RECORD.--Water years 1959-74, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 13... 1130 347 237 7.8 24.5 54 7.8 94 <10 26000 6100 FEB 22... 1105 72 300 7.7 22.0 170 8.0 92 <10 3000 3000 MAY 19... 1230 68 283 7.8 33.0 10 7.0 99 <10 2900 240 AUG 09... 1215 81 270 8.1 32.0 7.9 6.8 95 <10 E11000 7700 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 13... 89 24 7.2 11 .5 2.5 77 <1.0 17 11 FEB 22... -- -- -- -- -- -- 98 -- -- -- MAY 19... 100 28 7.9 14 .6 2.4 95 <1.0 19 17 AUG 09... 100 28 8.0 13 .6 2.5 90 -- 18 13 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 13... <.10 26 144 135 128 1.38 .020 1.40 .020 .21 FEB 22... -- -- -- -- 400 1.26 .038 1.30 .030 .96 MAY 19... .11 25 171 31.2 7 .650 .030 .680 .030 -- AUG 09... <.10 28 164 36.0 32 1.07 .030 1.10 .060 .20 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 13... .23 1.6 7.2 .210 <1 <100 20 <1 3 <10 FEB 22... .99 2.3 10 .340 -- -- -- -- -- -- MAY 19... <.20 -- -- E.070 <1 40 30 <1 <1 <12 AUG 09... .26 1.4 6.0 .120 -- -- -- -- -- -- 68 RIO GRANDE DE ARECIBO BASIN 50025000 RIO GRANDE DE ARECIBO NEAR UTUADO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 13... -- 3 220 <.10 <1 <1 20 <.010 <4 <.02 FEB 22... -- -- -- -- -- -- -- -- -- -- MAY 19... 260 <1 26 <.10 <1 <1 <40 <.010 <4 .09 AUG 09... -- -- -- -- -- -- -- -- -- -- 69 RIO GRANDE DE 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 Dam,4.8 mi (7.72 km) southeast of Utuado Plaza and 2.78 mi (4.47 km) east of Lago Viví Dam. DRAINAGE AREA.--37.94 mi2 (98.26 km2). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--October 1995 to current year. GAGE.--Water-stage recorder. Elevation of gage is 984 ft (300 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 254 298 e149 87 e68 43 29 35 131 49 104 160 2 226 e329 e190 86 e75 46 44 32 323 81 69 237 3 188 e330 e191 85 e62 41 153 30 220 57 40 177 4 160 236 e157 82 e59 37 133 30 139 47 47 118 5 143 200 e144 82 e57 37 79 49 e142 53 216 236 6 125 176 e134 80 e54 36 61 58 e109 46 113 349 7 142 175 e128 78 e54 38 51 47 e79 40 63 458 8 235 159 e123 76 e52 44 52 67 299 81 46 340 9 222 158 e119 76 e51 41 76 54 333 62 35 599 10 156 157 e114 78 e50 44 86 45 345 38 29 328 11 146 146 115 79 e50 38 65 81 255 36 25 238 12 123 203 113 73 e49 41 46 72 206 36 24 181 13 110 229 111 72 e48 41 41 50 138 36 59 e486 14 e129 184 109 e71 e52 36 38 55 102 39 117 e492 15 140 188 110 e72 e60 34 35 43 205 48 66 348 16 213 187 105 e102 e55 34 33 39 289 37 76 251 17 150 163 102 e92 e50 34 31 37 272 45 73 202 18 110 145 100 e75 e46 34 30 36 205 34 30 173 19 e93 135 99 e68 e45 51 30 35 165 29 64 675 20 81 130 109 e65 e44 62 29 32 129 31 73 484 21 109 122 99 e62 e43 38 29 31 99 58 37 e287 22 196 117 95 e61 e43 52 29 63 100 31 207 e207 23 176 123 104 e60 e42 36 83 47 83 46 124 e173 24 139 129 96 e59 e41 36 119 33 65 67 69 e179 25 214 113 92 e58 e42 36 75 34 56 25 46 e164 26 473 110 90 e58 e46 40 99 34 50 22 40 161 27 e1200 146 e88 e57 45 34 65 35 47 22 61 140 28 792 169 e90 86 45 33 47 35 45 25 45 214 29 396 e146 e107 64 --- 34 66 34 112 31 766 159 30 382 e129 91 59 --- 38 52 42 80 30 416 142 31 458 --- 89 59 --- 35 --- 59 --- 24 220 --- TOTAL 7681 5232 3563 2262 1428 1224 1806 1374 4823 1306 3400 8358 MEAN 248 174 115 73.0 51.0 39.5 60.2 44.3 161 42.1 110 279 MAX 1200 330 191 102 75 62 153 81 345 81 766 675 MIN 81 110 88 57 41 33 29 30 45 22 24 118 AC-FT 15240 10380 7070 4490 2830 2430 3580 2730 9570 2590 6740 16580 CFSM 6.53 4.60 3.03 1.92 1.34 1.04 1.59 1.17 4.24 1.11 2.89 7.34 IN. 7.53 5.13 3.49 2.22 1.40 1.20 1.77 1.35 4.73 1.28 3.33 8.19 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1996 - 1999, BY WATER YEAR (WY) MEAN 151 105 65.2 58.1 57.6 39.7 61.7 82.5 83.5 59.2 94.1 379 MAX 248 174 115 89.8 86.0 51.3 112 130 161 117 156 815 (WY) 1999 1999 1999 1997 1996 1996 1998 1998 1999 1996 1998 1998 MIN 72.9 44.2 21.0 19.6 41.9 25.7 17.0 29.1 16.1 15.5 47.9 33.2 (WY) 1997 1998 1998 1998 1997 1997 1997 1997 1997 1997 1996 1997 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1996 - 1999 ANNUAL TOTAL 60677.0 42457 ANNUAL MEAN 166 116 103 HIGHEST ANNUAL MEAN 137 1998 LOWEST ANNUAL MEAN 49.9 1997 HIGHEST DAILY MEAN 13000 Sep 22 1200 Oct 27 13000 Sep 22 1998 LOWEST DAILY MEAN 14 Jan 4 22 Jul 26 10 Jul 4 1997 ANNUAL SEVEN-DAY MINIMUM 14 Jan 28 26 Jul 25 11 Jul 1 1997 INSTANTANEOUS PEAK FLOW 10100 Oct 27 36000 Sep 22 1998 INSTANTANEOUS PEAK STAGE 18.80 Oct 27 31.15 Sep 22 1998 INSTANTANEOUS LOW FLOW 9.5 Jul 6 1997 ANNUAL RUNOFF (AC-FT) 120400 84210 74510 ANNUAL RUNOFF (CFSM) 4.38 3.07 2.71 ANNUAL RUNOFF (INCHES) 59.49 41.63 36.83 10 PERCENT EXCEEDS 264 231 187 50 PERCENT EXCEEDS 92 75 52 90 PERCENT EXCEEDS 21 34 19 e Estimated 70 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 71 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS 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, 24,800 mg/L September 22, 1998 ; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, e952,ooo tons (e864,000 tonnes) September 22, 1998; Minimum daily mean, 0.04 ton (0.03 tonne) December 29-30, 1998. EXTREMES FOR CURRENT YEAR 1999. SEDIMENT CONCENTRATION: Maximum daily mean, 5,360 mg/L August 29, 1999; Minimum daily mean, 7 mg/L July 28, 1999. SEDIMENT LOADS: Maximum daily mean, 62,600 tons (56,800 tonnes) October 27, 1998; Minimum daily mean, 0.72 ton (0.65 tonne) April 20, 1999. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 254 10 6.8 298 114 92 e149 e49 e20 2 226 43 26 e329 e470 e580 e190 e118 e67 3 188 54 28 e330 e717 e908 e191 e500 e263 4 160 26 11 236 309 203 e157 e183 e78 5 143 31 12 200 88 48 e144 e174 e67 6 125 24 8.1 176 77 37 e134 e169 e61 7 142 97 50 175 135 70 e128 e164 e57 8 235 413 393 159 213 92 e123 e158 e53 9 222 236 151 158 194 84 e119 e175 e56 10 156 47 20 157 182 77 e114 e218 e67 11 146 77 35 146 165 65 115 64 20 12 123 111 38 203 344 298 113 44 14 13 110 125 38 229 1200 1090 111 40 12 14 e129 e176 e65 184 470 590 109 51 15 15 140 208 88 188 630 628 110 59 17 16 213 364 507 187 630 632 105 44 12 17 150 74 33 163 350 436 102 34 9.3 18 110 71 21 145 244 96 100 32 8.6 19 e93 e57 e14 135 176 65 99 31 8.4 20 81 45 9.8 130 54 19 109 32 9.3 21 109 89 37 122 37 12 99 33 8.9 22 196 356 218 117 20 6.4 95 39 10 23 176 186 95 123 27 9.2 104 44 12 24 139 77 30 129 69 24 96 31 8.1 25 214 358 456 113 84 26 92 21 5.3 26 473 1100 3760 110 36 11 90 21 5.0 27 e1200 e4120 e62600 146 96 52 e88 e21 e4.9 28 792 666 2120 169 202 104 e90 e20 e4.9 29 396 148 159 e146 e120 e49 e107 e98 e29 30 382 481 822 e129 e51 e18 91 66 16 31 458 470 916 --- --- --- 89 27 6.6 TOTAL 7681 --- 72767.7 5232 --- 6421.6 3563 --- 1025.3 72 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 87 20 4.7 e68 e28 e5.8 43 27 3.2 2 86 17 3.9 e75 e53 e11 46 31 4.1 3 85 19 4.5 e62 e26 e4.4 41 28 3.1 4 82 23 5.1 e59 e22 e3.5 37 19 1.9 5 82 27 6.1 e57 e19 e3.0 37 16 1.6 6 80 34 7.3 e54 e15 e2.2 36 20 2.0 7 78 46 9.8 e54 e12 e1.8 38 27 2.8 8 76 62 13 e52 e13 e1.8 44 36 4.2 9 76 47 9.6 e51 e13 e1.8 41 33 3.6 10 78 29 6.1 e50 e12 e1.6 44 30 3.6 11 79 37 7.8 e50 e11 e1.5 38 25 2.5 12 73 58 11 e49 e11 e1.4 41 23 2.7 13 72 59 11 e48 e10 e1.3 41 39 4.4 14 e71 e51 e9.7 e52 e11 e1.6 36 20 1.9 15 e72 e49 e9.7 e60 e66 e11 34 12 1.1 16 e102 e100 e28 e55 e32 e4.7 34 11 1.0 17 e92 e48 e12 e50 e17 e2.2 34 11 1.0 18 e75 e26 e5.2 e46 e18 e2.3 34 11 .96 19 e68 e32 e5.9 e45 e19 e2.3 51 27 6.2 20 e65 e40 e7.1 e44 e14 e1.6 62 45 9.3 21 e62 e39 e6.6 e43 e10 e1.2 38 24 2.8 22 e61 e34 e5.6 e43 e13 e1.6 52 36 5.7 23 e60 e23 e3.8 e42 e19 e2.1 36 16 1.6 24 e59 e19 e3.0 e41 e18 e2.0 36 13 1.2 25 e58 e33 e5.2 e42 e17 e1.9 36 10 1.0 26 e58 e56 e8.8 e46 e18 e2.3 40 10 1.1 27 e57 e58 e8.9 45 21 2.5 34 10 .94 28 86 84 20 45 24 2.9 33 11 1.0 29 64 79 14 --- --- --- 34 13 1.2 30 59 72 12 --- --- --- 38 17 1.9 31 59 36 5.8 --- --- --- 35 28 2.7 TOTAL 2262 --- 271.2 1428 --- 83.3 1224 --- 82.30 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) APRIL MAY JUNE 1 29 16 1.3 35 30 2.8 131 830 855 2 44 25 4.0 32 22 1.9 323 778 1750 3 153 1090 1260 30 17 1.4 220 750 962 4 133 182 74 30 16 1.3 139 132 52 5 79 44 9.5 49 36 7.3 e142 e366 e548 6 61 28 4.6 58 180 48 e109 e69 e22 7 51 21 3.0 47 40 5.3 e79 32 6.9 8 52 27 4.1 67 180 78 299 698 1720 9 76 66 17 54 60 9.2 333 632 684 10 86 81 21 45 120 20 345 420 484 11 65 96 17 81 99 24 255 600 1440 12 46 46 5.7 72 138 28 206 230 138 13 41 23 2.5 50 73 9.7 138 134 51 14 38 13 1.3 55 41 6.1 102 59 16 15 35 9 .82 43 32 3.7 205 366 546 16 33 9 .82 39 24 2.5 289 499 697 17 31 10 .82 37 18 1.8 272 447 355 18 30 9 .76 36 12 1.1 205 129 75 19 30 9 .73 35 9 .88 165 61 28 20 29 9 .72 32 16 1.4 129 39 13 21 29 10 .75 31 24 2.1 99 39 10 22 29 12 .92 63 100 37 100 70 23 23 83 103 92 47 198 27 83 53 12 24 119 129 59 33 87 7.8 65 19 3.3 25 75 171 40 34 40 3.7 56 13 2.0 26 99 116 38 34 19 1.7 50 10 1.4 27 65 136 25 35 11 1.1 47 8 1.0 28 47 46 5.9 35 15 1.5 45 7 .83 29 66 48 16 34 20 1.9 112 360 453 30 52 43 6.2 42 33 4.4 80 83 21 31 --- --- --- 59 54 11 --- --- --- TOTAL 1806 --- 1713.44 1374 --- 353.58 4823 --- 10970.43 73 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 49 35 4.6 104 622 560 160 85 39 2 81 58 14 69 81 19 237 630 708 3 57 51 7.9 40 38 4.1 177 253 140 4 47 37 4.7 47 34 6.8 118 42 14 5 53 39 5.9 216 996 1560 236 368 489 6 46 48 6.0 113 110 38 349 944 1960 7 40 34 3.7 63 37 6.5 458 1330 2640 8 81 78 34 46 29 3.6 340 821 808 9 62 46 8.5 35 25 2.3 599 1900 8780 10 38 26 2.7 29 21 1.6 328 462 447 11 36 31 3.1 25 17 1.2 238 228 162 12 36 38 3.7 24 14 .94 181 550 608 13 36 30 2.9 59 157 97 e486 e1570 e2640 14 39 22 2.3 117 137 60 e492 e843 e1210 15 48 30 4.2 66 59 12 348 321 321 16 37 24 2.4 76 170 100 251 342 236 17 45 33 4.2 73 50 12 202 162 89 18 34 39 3.6 30 21 1.8 173 77 36 19 29 20 1.6 64 181 91 675 615 2880 20 31 14 1.3 73 162 12 484 994 1420 21 58 170 78 37 32 3.2 e287 e416 e344 22 31 33 2.8 207 485 751 e207 e122 e69 23 46 146 58 124 146 57 e173 e117 e55 24 67 77 20 69 39 7.3 e179 e204 e110 25 25 32 2.1 46 25 3.2 e164 e218 e101 26 22 27 1.6 40 20 2.3 161 180 79 27 22 23 1.4 61 45 8.4 140 148 56 28 25 19 1.3 45 28 4.6 214 322 224 29 31 25 3.2 766 5360 47000 159 183 79 30 30 36 3.2 416 541 878 142 133 53 31 24 10 .65 220 273 170 --- --- --- TOTAL 1306 --- 293.55 3400 --- 51474.84 8358 --- 26797 YEAR 42457 172254.24 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) OCT 07... 1600 119 197 63 95 22... 0700 208 1260 708 93 29... 1315 358 143 138 83 NOV 03... 0900 260 227 159 84 29... 0700 150 128 52 93 DEC 07... 0700 129 949 331 74 29... 1100 122 178 59 96 JAN 30... 1500 59 76 12 98 APR 03... 1700 286 6070 4690 88 03... 1915 446 6020 7240 83 MAY 23... 1100 46 192 24 81 AUG 01... 1800 300 5110 4140 93 05... 1600 815 5850 12900 78 29... 1958 4420 53200 634000 35 SEP 02... 1930 609 3410 5610 66 07... 1615 1330 8080 29000 61 09... 1628 2260 12600 77000 61 13... 0900 707 2640 5040 73 13... 2228 938 3510 8890 68 74 RIO GRANDE DE ARECIBO BASIN 50026025 RIO CAONILLAS AT PASO PALMA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. SED. CHARGE, MENT, SUSP. SUSP. SUSP. INST. SEDI- DIS- FALL FALL FALL CUBIC MENT, CHARGE, DIAM. DIAM. DIAM. FEET SUS- SUS- % FINER % FINER % FINER DATE TIME PER PENDED PENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) OCT 22... 0700 208 1260 708 42 53 69 APR 03... 1915 446 6020 7240 32 43 56 AUG 05... 1600 815 5850 12900 27 35 47 29... 1958 4420 53200 634000 6 9 12 SEP 07... 1615 1330 8080 29000 20 26 35 WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) OCT 22... 79 90 93 98 100 100 100 APR 03... 70 78 83 90 95 98 100 AUG 05... 60 72 78 84 90 96 99 29... 16 25 35 62 90 98 100 SEP 07... 44 55 61 75 88 96 99 75 RIO GRANDE DE ARECIBO BASIN 50026050 RIO CAONILLAS ABOVE LAGO 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 mi (5.3 km) northwest of Jayuya plaza. DRAINAGE AREA.--40.4 mi2 (104.6 km2). PERIOD OF RECORD.--Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 24... 1100 147 170 7.7 24.5 120 7.5 93 <10 42000 26000 FEB 23... 1015 37 265 7.8 22.5 3.5 8.3 98 <10 K10 K90 MAY 20... 1310 35 256 8.0 32.0 1.9 6.6 94 <10 K20 K30 AUG 10... 1100 47 245 8.0 27.4 1.4 8.6 113 <10 K40 K20 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 24... 74 19 6.1 9.4 .5 1.7 69 <1.0 12 10 FEB 23... -- -- -- -- -- -- 91 -- -- -- MAY 20... 98 27 7.4 13 .6 1.8 85 <1.0 17 14 AUG 10... 93 25 7.2 11 .5 1.8 81 -- 15 11 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 24... <.10 23 124 49.2 232 1.19 .013 1.20 .020 .74 FEB 23... -- -- -- -- 5 -- <.010 1.10 .020 .20 MAY 20... <.10 26 157 14.8 <1 -- <.010 .380 .020 -- AUG 10... <.10 26 147 18.6 6 -- <.010 .590 <.010 -- NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 24... .76 2.0 8.7 .250 <1 <100 20 <1 3 26 FEB 23... .22 1.3 5.8 .070 -- -- -- -- -- -- MAY 20... <.20 -- -- E.040 <1 30 30 <1 <1 E6 AUG 10... <.20 -- -- .060 -- -- -- -- -- -- 76 RIO GRANDE DE ARECIBO BASIN 50026050 RIO CAONILLAS ABOVE LAGO CAONILLAS NEAR JAYUYA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 24... 4600 2 250 <.10 <1 <1 30 <.010 <4 .06 FEB 23... -- -- -- -- -- -- -- -- -- -- MAY 20... 120 <1 8 <.10 <1 <1 <40 <.010 <4 -- AUG 10... -- -- -- -- -- -- -- -- -- -- 77 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 Caonillas Dam on Río Caonillas, 2.9 mi (4.7 km) northeast of Plaza de Utuado, 0.3 mi (0.6 km) west from Iglesia Santa María del Monte Carmelo, and 1.8 mi (3.0 km) northwest from Hacienda Carbonell. DRAINAGE AREA.--48.4 mi2 (125.4 km2). ELEVATION RECORDS PERIOD OF RECORD.--March 1991 to current year. (March 16 to September 30, 1999, no records available due to repairs conducted by Puerto Rico Electric and Power Authority; inspections data available at District Office). 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. New capacity table based on U.S. Geological Survey Water-Resources Investigations Report 96-4153,Februay 1995. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 841.29 ft (256.42 m), Sept. 22, 1998; minimun elevation, 737.92 ft (224.92 m), Aug. 8, 1997. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 830.10 ft (253.01 m), Oct. 27; minimum elevation, 826.88 ft (252.03 m), Oct. 27. Capacity Table (based on data from U.S. Geological Survey Water-Resources Investigations Report 96-4153,Puerto Rico-1995) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 689 0 745 6,015 705 778 764 10,077 725 2,919 830 42,295 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 826.57 826.94 826.77 826.05 826.40 826.29 A A A A A A 2 826.53 827.14 827.36 826.07 826.44 826.34 A A A A A A 3 826.46 827.16 827.13 826.07 826.40 826.28 A A A A A A 4 826.43 826.81 826.80 826.09 826.37 826.22 A A A A A A 5 826.44 826.67 826.63 826.14 826.34 826.16 A A A A A A 6 826.42 826.60 826.52 826.16 826.33 826.11 A A A A A A 7 826.50 826.59 826.45 826.16 826.32 826.09 A A A A A A 8 827.19 826.52 826.41 826.16 826.30 826.07 A A A A A A 9 826.69 826.55 826.39 826.17 826.30 826.09 A A A A A A 10 826.50 826.56 826.38 826.21 826.30 826.08 A A A A A A 11 826.45 826.53 826.37 826.21 826.30 826.07 A A A A A A 12 826.41 826.85 826.34 826.20 826.30 826.07 A A A A A A 13 826.42 826.78 826.34 826.22 826.29 826.07 A A A A A A 14 826.52 826.69 826.33 826.20 826.30 826.04 A A A A A A 15 826.65 826.70 826.33 826.55 826.36 826.02 A A A A A A 16 826.94 826.73 826.30 826.45 826.37 A A A A A A A 17 826.67 826.66 826.28 826.33 826.35 A A A A A A A 18 826.52 826.61 826.23 826.25 826.27 A A A A A A A 19 826.47 826.57 826.24 826.23 826.17 A A A A A A A 20 826.42 826.56 826.26 826.23 826.10 A A A A A A A 21 826.47 826.53 826.21 826.23 826.05 A A A A A A A 22 826.63 826.51 826.19 826.23 826.01 A A A A A A A 23 826.63 826.52 826.18 826.25 825.96 A A A A A A A 24 826.59 826.53 826.13 826.26 825.95 A A A A A A A 25 827.13 826.49 826.09 826.28 826.20 A A A A A A A 26 827.50 826.46 826.05 826.33 826.44 A A A A A A A 27 829.55 826.59 826.02 826.32 826.34 A A A A A A A 28 827.64 826.69 826.02 826.42 826.36 A A A A A A A 29 827.04 826.65 826.05 826.38 --- A A A A A A A 30 827.16 826.63 826.05 826.33 --- A A A A A A A 31 827.04 --- 826.05 826.32 --- A --- A --- A A --- MAX 829.55 827.16 827.36 826.55 826.44 --- --- --- --- --- --- --- MIN 826.41 826.46 826.02 826.05 825.95 --- --- --- --- --- --- --- A No gage-height record 78 RIO GRANDE DE ARECIBO BASIN 50027100 LAGO DOS BOCAS AT DAMSITE NEAR UTUADO, PR LOCATION.--Lat 18°20'16",long 66°40'05", Hydrologic Unit 21010001, on upstream side of road 146 near bridge center, 10 mi (16.09 km) southeast of the city of Arecibo, 4.10 mi (6.596 km) north of Lago Caonillas Dam, 5.30 mi (8.527 km) northeast of Plaza de Utuado, and 3.80 mi (6.114 km) southeast of Escuela Antonio Sánchez de Padilla. DRAINAGE AREA.--169.45 mi2 (438.87 km2). ELEVATION RECORDS PERIOD OF RECORD.--March 1999 to current year. GAGE.--Water stage recorder. Datum of gage is mean sea level. REMARKS.--Lago Dos Bocas was completed in 1942. The dam is a concrete gravity structure with a total length of 1,317 ft (401.42 m), a maximum height of 188 ft (57.302 m), and a maximum base width of 158 ft (48.158 m). No-overflow sections on each abutment have a total lenght of 957 ft (292 m). The dam and the powerplant comprise the Dos Bocas Hydroelectric Project, and provides 32,000 acre-feet (39.456 hm3). A three-unit powerplant is located on the right bank of the slitting basin. The dam is owned by Puerto Rico Electric Power Authority. The capacity of Lago Dos Bocas was computed to be 714.40 million ft3 (20.23 million m3) for June 1997. The Puerto Rico Aqueduct and Sewer Authority (PRASA) plans to withdraw water from the Río Grande de Arecibo, south of the town of Arecibo, to supply potable water for areas between Arecibo and San Juan town. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation,296.83 ft (90.473 m), June 9, 1999; minimum elevation,286.39 ft (87.291 m), Aug. 8, 1999. Capacity Table (based on data from U.S. Geological Survey Water-Resources Investigations Report 98-4188,1997) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 216 0 275 9,283 236 1,403 288 13,684 256 4,491 295 16,400 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 289.90 290.97 291.92 291.89 290.42 A 2 290.96 290.67 293.92 293.10 290.30 A 3 293.69 290.64 295.05 290.23 289.02 A 4 294.09 290.61 293.19 290.44 290.22 A 5 293.18 291.48 290.75 292.33 292.05 A 6 291.58 293.96 291.09 292.11 292.30 A 7 290.07 293.09 291.57 291.02 289.89 A 8 289.86 294.64 295.50 292.06 288.40 A 9 289.09 292.15 296.08 292.87 288.28 A 10 290.03 292.18 294.70 292.09 287.90 A 11 291.13 290.79 295.17 292.96 290.33 A 12 290.76 291.56 294.13 292.70 291.49 A 13 288.26 290.99 293.83 291.24 292.51 A 14 287.94 290.29 292.82 A 293.03 A 15 287.97 289.76 294.97 292.85 292.91 290.73 16 288.71 290.53 294.85 A 292.49 A 17 289.37 289.97 293.93 294.15 291.39 A 18 290.02 290.36 293.46 291.38 290.11 288.39 19 290.37 290.00 293.79 291.95 287.25 290.42 20 290.16 290.61 293.44 290.80 289.84 A 21 290.53 290.08 293.32 290.49 291.77 A 22 289.86 290.94 293.98 290.24 293.83 A 23 292.17 291.82 292.94 290.76 292.75 A 24 293.22 290.84 292.34 291.47 291.36 A 25 293.24 289.46 291.80 292.24 A A 26 293.26 290.11 293.50 293.21 A 291.41 27 292.83 290.62 293.27 293.39 A 291.02 28 293.11 290.96 293.47 293.63 A 290.78 29 291.78 291.57 293.54 293.14 292.17 290.85 30 288.09 291.43 293.41 292.78 292.60 292.10 290.79 31 288.86 --- 294.71 --- 290.02 --- --- MAX --- 294.09 294.71 296.08 --- --- --- MIN --- 287.94 289.46 290.75 --- --- --- A No gage-height record 79 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 Dos Bocas and 6.6 mi (10.6 km) west of Florida plaza. DRAINAGE AREA.--169 mi2 (436 km2) does not include 6.0 mi2 (15.6 km2) above Lago Garzas. PERIOD OF RECORD.--Water years 1970-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 24... 0945 E1500 209 7.3 25.0 22 6.4 77 <10 300 400 FEB 22... 0800 33 258 7.6 23.0 3.2 6.8 79 <10 K10 280 MAY 19... 0845 28 216 7.3 26.5 5.7 5.8 73 <10 <10 K80 AUG 10... 0835 41 209 8.0 26.5 3.5 6.0 75 11 E110 E180 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 24... 77 21 6.3 9.1 .5 2.3 69 <1.0 12 10 FEB 22... -- -- -- -- -- -- 89 -- -- -- MAY 19... 78 21 6.1 9.9 .5 2.2 74 <1.0 12 12 AUG 10... 82 22 6.4 9.2 .4 2.1 76 -- 11 10 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 24... <.10 23 126 -- 18 -- <.010 1.30 .020 .22 FEB 22... -- -- -- -- 2 .830 .020 .850 .040 .19 MAY 19... <.10 20 128 9.54 1 .550 .010 .560 .050 -- AUG 10... <.10 22 129 14.3 4 .180 .020 .200 .150 .09 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 24... .24 1.5 6.8 .060 <1 <100 <10 <1 1 <10 FEB 22... .23 1.1 4.8 .060 -- -- -- -- -- -- MAY 19... E.21 -- -- E.020 <1 40 E20 <1 <1 <12 AUG 10... .24 .44 1.9 .020 -- -- -- -- -- -- 80 RIO GRANDE DE ARECIBO BASIN 50027250 RIO GRANDE DE ARECIBO BELOW LAGO DOS BOCAS NEAR FLORIDA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 24... 760 <1 91 .17 <1 <1 <10 <.010 <4 <.02 FEB 22... -- -- -- -- -- -- -- -- -- -- MAY 19... 300 <1 88 <.10 <1 <1 <40 <.010 7 <.02 AUG 10... -- -- -- -- -- -- -- -- -- -- 81 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR LOCATION.--Lat 18°25'22', long 66°41'58", Hydrologic Unit 21010002, 0.5 mi (0.8 km) upstream from Río Tanamá, 3.6 mi (5.8 km), south of Arecibo and 4.9 mi (7.9 km) above mouth, and 10.4 mi (16.7 km) downstream from Lago Dos Bocas. DRAINAGE AREA.--174 mi2 (451 km2), 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e1100 e165 e440 e220 e310 344 69 176 975 411 328 420 2 e920 e150 e470 e180 e240 248 80 234 785 226 319 355 3 e960 e145 e1300 e160 e260 84 547 211 726 445 396 500 4 e720 e155 e1200 e310 e230 197 579 279 843 394 273 530 5 e860 e165 e780 e380 e160 317 567 68 1020 200 187 614 6 e860 e180 e680 e310 e115 416 541 126 208 194 322 498 7 e850 e88 e600 e260 e91 210 459 565 442 359 348 843 8 e890 e250 e520 e160 e110 67 324 386 168 328 441 722 9 e2200 e720 e330 e270 e86 203 315 749 1010 153 258 894 10 e1000 e680 e520 e210 e123 212 248 397 1270 334 297 728 11 e700 e560 e440 e280 e103 68 137 594 993 286 204 640 12 e600 e500 e180 e350 e170 198 159 120 807 258 155 632 13 e480 e780 e150 e90 e390 339 494 288 560 296 137 574 14 e315 e740 e300 e120 e230 223 272 314 499 241 e110 731 15 e270 e470 e190 e490 e145 105 306 157 611 131 350 875 16 e340 e560 e150 e150 e160 178 84 273 946 292 474 870 17 e580 e580 e145 e300 e190 70 57 204 1160 e190 501 446 18 e370 e510 e152 e440 e160 149 54 124 754 e370 399 562 19 e250 e500 e260 e280 e56 60 48 198 738 e350 784 555 20 e170 e580 e190 e58 e53 494 135 122 441 319 324 396 21 e135 e350 e160 e120 e72 340 122 98 575 371 e150 481 22 e129 e250 e210 e215 e52 485 130 191 327 450 184 512 23 e96 e440 e190 e130 e45 625 191 70 510 291 559 534 24 e430 e450 e165 e115 e45 239 115 274 425 e200 434 382 25 e148 e425 e190 e220 e220 87 153 331 410 85 e480 276 26 e125 e260 e148 e370 441 352 536 149 186 118 e542 397 27 e103 e310 e370 e220 716 210 322 e70 134 e120 457 547 28 e1500 e660 e270 e140 268 511 148 e82 293 e90 317 549 29 e780 e560 e240 e110 --- 578 446 201 367 183 176 399 30 e330 e410 e210 e96 --- 540 316 194 308 291 356 460 31 e210 --- e170 e92 --- 174 --- 367 --- 466 491 --- TOTAL 18421 12593 11320 6846 5241 8323 7954 7612 18491 8442 10753 16922 MEAN 594 420 365 221 187 268 265 246 616 272 347 564 MAX 2200 780 1300 490 716 625 579 749 1270 466 784 894 MIN 96 88 145 58 45 60 48 68 134 85 110 276 AC-FT 36540 24980 22450 13580 10400 16510 15780 15100 36680 16740 21330 33560 CFSM 3.42 2.41 2.10 1.27 1.08 1.54 1.52 1.41 3.54 1.57 1.99 3.24 IN. 3.94 2.69 2.42 1.46 1.12 1.78 1.70 1.63 3.95 1.80 2.30 3.62 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1982 - 1999, BY WATER YEAR (WY) MEAN 585 496 282 239 221 211 326 530 349 244 264 529 MAX 1984 1413 570 437 428 351 617 2000 683 374 474 1479 (WY) 1986 1986 1988 1988 1988 1985 1986 1986 1987 1987 1988 1996 MIN 171 123 72.4 83.5 61.2 60.1 65.7 178 69.3 62.7 82.8 99.9 (WY) 1995 1995 1995 1995 1995 1998 1995 1994 1994 1994 1994 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1982 - 1999 ANNUAL TOTAL 116991 132918 ANNUAL MEAN 321 364 356 HIGHEST ANNUAL MEAN 729 1986 LOWEST ANNUAL MEAN 132 1994 HIGHEST DAILY MEAN 7290 Sep 22 2200 Oct 9 14800 May 18 1985 LOWEST DAILY MEAN 22 Mar 11 45 Feb 23 16 Apr 14 1994 ANNUAL SEVEN-DAY MINIMUM 24 Mar 11 69 Feb 18 22 Mar 30 1994 INSTANTANEOUS PEAK FLOW Not determined Oct 28 45800 May 18 1985 INSTANTANEOUS PEAK STAGE Not determined Oct 28 18.22 May 18 1985 ANNUAL RUNOFF (AC-FT) 232100 263600 257700 ANNUAL RUNOFF (CFSM) 1.84 2.09 2.04 ANNUAL RUNOFF (INCHES) 25.01 28.42 27.78 10 PERCENT EXCEEDS 684 727 732 50 PERCENT EXCEEDS 210 306 236 90 PERCENT EXCEEDS 41 108 55 e Estimated 82 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 83 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE 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 automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 3,510 mg/L September 22, 1998; Minimum daily mean, 2 mg/L several years. SEDIMENT LOADS: Maximum daily mean, e84,900 tons (77,000 tonnes) September 22,1998; Minimum daily mean, 0.14 ton (0.013 tonne) March 24, 1998. EXTREMES FOR CURRENT YEAR 1999. SEDIMENT CONCENTRATION: Maximum daily mean, 398 mg/L October 9, 1998; Minimum daily mean, 11 mg/L April 19 and August 21, 1999. SEDIMENT LOADS: Maximum daily mean, 946 tons (858 tonnes) June 10, 1999; Minimum daily mean, 1.6 ton (1.45 tonnes) April 19, 1999. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 e1100 e206 e427 e165 e43 e64 e440 e91 e170 2 e920 e160 e357 e150 e40 e58 e470 e96 e182 3 e960 e181 e372 e145 e39 e56 e1300 e241 e504 4 e720 e140 e279 e155 e41 e60 e1200 e223 e465 5 e860 e164 e333 e165 e43 e64 e780 e150 e302 6 e860 e164 e333 e180 e45 e69 e680 e133 e263 7 e850 e163 e330 e88 e29 e34 e600 e119 e232 8 e890 e169 e345 e250 e58 e97 e520 e105 e201 9 e2200 e398 e854 e720 e140 e279 e330 e72 e128 10 e1000 e188 e388 e680 e133 e263 e520 e105 e201 11 e700 e136 e271 e560 e112 e217 e440 e91 e170 12 e600 e119 e232 e500 e101 e194 e180 e45 e69 13 e480 e98 e186 e780 e150 e302 e150 e40 e58 14 e315 e69 e122 e740 e143 e287 e300 e66 e116 15 e270 e62 e104 e470 e96 e182 e190 e47 e73 16 e340 e74 e131 e560 e112 e217 e150 e40 e58 17 e580 e116 e225 e580 e115 e225 e145 e39 e56 18 e370 e79 e143 e510 e103 e197 e152 e41 e59 19 e250 e58 e97 e500 e101 e194 e260 e59 e100 20 e170 e44 e65 e580 e115 e225 e190 e47 e73 21 e135 e38 e52 e350 e75 e135 e160 e42 e62 22 e129 e37 e50 e250 e58 e97 e210 e51 e81 23 e96 e31 e37 e440 e91 e170 e190 e47 e73 24 e430 e89 e166 e450 e93 e174 e165 e43 e64 25 e148 e40 e57 e425 e88 e164 e190 e47 e73 26 e125 e36 e48 e260 e59 e100 e148 e40 e57 27 e103 e32 e39 e310 e68 e120 e370 e79 e143 28 e1500 e275 e582 e660 e129 e256 e270 e61 e104 29 e780 e150 e302 e560 e112 e217 e240 e56 e93 30 e330 e72 e128 e410 e86 e159 e210 e51 e81 31 e210 e51 e81 --- --- --- e170 e44 e65 TOTAL 18421 --- 7136 12593 --- 4876 11320 --- 4376 84 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 e220 e52 e85 e310 e68 e120 344 64 93 2 e180 e45 e69 e240 e56 e93 248 57 73 3 e160 e42 e62 e260 e59 e100 84 21 6.5 4 e310 e68 e120 e230 e54 e89 197 48 48 5 e380 e80 e147 e160 e42 e62 317 62 114 6 e310 e68 e120 e115 e34 e44 416 89 144 7 e260 e59 e100 e91 e30 e35 210 49 56 8 e160 e42 e62 e110 e33 e42 67 16 4.8 9 e270 e61 e104 e86 e29 e33 203 48 48 10 e210 e51 e81 e123 e36 e47 212 49 44 11 e280 e63 e108 e103 e32 e39 68 18 3.4 12 e350 e75 e135 e170 e44 e65 198 18 13 13 e90 e30 e34 e390 e82 e151 339 49 69 14 e120 e35 e46 e230 e54 e89 223 52 51 15 e490 e99 e190 e145 e39 e56 105 25 13 16 e150 e40 e58 e160 e42 e62 178 44 38 17 e300 e66 e116 e190 e47 e73 70 17 3.6 18 e440 e91 e170 e160 e42 e62 149 33 24 19 e280 e63 e108 e56 e24 e21 60 16 2.8 20 e58 e24 e22 e53 e23 e20 494 101 218 21 e120 e35 e46 e72 e27 e27 340 81 111 22 e215 e52 e83 e52 e23 e20 485 104 180 23 e130 e37 e50 e45 e22 e17 625 137 322 24 e115 e34 e44 e45 e22 e17 239 57 70 25 e220 e52 e85 e220 e52 e85 87 22 5.8 26 e370 e79 e143 441 94 155 352 78 132 27 e220 e52 e85 716 163 333 210 49 52 28 e140 e39 e54 268 62 82 511 107 246 29 e110 e33 e42 --- --- --- 578 126 283 30 e96 e31 e37 --- --- --- 540 122 238 31 e92 e30 e35 --- --- --- 174 41 23 TOTAL 6846 --- 2641 5241 --- 2039 8323 --- 2729.9 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) APRIL MAY JUNE 1 69 19 3.9 176 40 28 975 226 598 2 80 20 9.1 234 55 70 785 168 394 3 547 116 229 211 52 59 726 126 264 4 579 131 260 279 66 73 843 166 395 5 567 120 246 68 19 3.7 1020 216 599 6 541 117 238 126 29 27 208 51 38 7 459 97 154 565 122 266 442 85 107 8 324 71 94 386 90 120 168 41 22 9 315 70 84 749 140 368 1010 206 695 10 248 55 69 397 90 155 1270 266 946 11 137 30 15 594 128 275 993 216 578 12 159 37 32 120 32 13 807 171 398 13 494 99 225 288 63 81 560 127 206 14 272 59 89 314 71 81 499 109 189 15 306 66 83 157 36 21 611 125 285 16 84 21 5.3 273 34 36 946 205 546 17 57 12 1.8 204 46 41 1160 232 727 18 54 11 1.7 124 27 11 754 162 377 19 48 12 1.6 198 45 31 738 160 352 20 135 33 17 122 29 13 441 103 168 21 122 30 14 98 24 10 575 126 226 22 130 33 18 191 42 36 327 74 75 23 191 45 45 70 18 3.3 510 106 162 24 115 27 15 274 21 21 425 91 115 25 153 35 20 331 19 25 410 87 110 26 536 116 229 149 25 13 186 46 33 27 322 72 115 e70 e14 e1.8 134 27 26 28 148 36 20 e82 e24 e7.6 293 69 71 29 446 97 178 201 49 33 367 83 94 30 316 75 93 194 42 24 308 72 77 31 --- --- --- 367 83 98 --- --- --- TOTAL 7954 --- 2605.4 7612 --- 2045.4 18491 --- 8873 85 RIO GRANDE DE ARECIBO BASIN 50027750 RIO GRANDE DE ARECIBO ABOVE ARECIBO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 411 90 112 328 77 101 420 38 54 2 226 53 44 319 76 73 355 48 48 3 445 95 149 396 89 120 500 65 118 4 394 90 114 273 65 68 530 93 141 5 200 51 34 187 41 29 614 94 167 6 194 43 45 322 73 79 498 94 199 7 359 85 107 348 75 115 843 258 597 8 328 77 79 441 81 109 722 195 399 9 153 38 20 258 63 56 894 195 482 10 334 76 78 297 71 68 728 174 360 11 286 68 64 204 46 34 640 111 207 12 258 61 64 155 38 20 632 82 148 13 296 67 84 137 32 15 574 83 138 14 241 58 67 e110 e28 e11 731 123 266 15 131 35 18 350 81 88 875 144 341 16 292 66 62 474 64 80 870 117 275 17 e190 e27 e16 501 45 62 446 79 102 18 e370 e71 e108 399 42 52 562 117 195 19 e350 e59 e83 784 168 357 555 125 215 20 319 74 80 324 32 46 396 60 88 21 371 84 120 e150 e11 e2.1 481 59 81 22 450 98 147 184 45 43 512 78 113 23 291 69 71 559 133 226 534 81 128 24 e200 e32 e13 434 89 122 382 83 103 25 85 22 7.7 e480 72 104 276 68 72 26 118 28 12 e542 72 111 397 91 118 27 e120 e35 e21 457 58 83 547 96 154 28 e90 24 7.7 317 63 76 549 71 122 29 183 45 33 176 44 27 399 75 96 30 291 65 70 356 57 58 460 78 121 31 466 104 165 491 50 79 --- --- --- TOTAL 8442 --- 2095.4 10753 --- 2514.1 16922 --- 5648 YEAR 132918 47579.2 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) MAY 16... 0315 904 72 176 96 25... 2235 712 59 113 87 AUG 07... 2337 784 55 116 86 16... 2354 730 38 75 72 25... 1814 810 76 166 92 SEP 01... 0002 801 53 115 97 03... 1932 905 132 323 95 07... 1445 809 287 627 93 08... 1226 464 186 233 89 08... 1440 713 184 354 95 27... 1937 824 92 205 92 29... 0040 732 68 134 85 86 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 mi2 (47.7 km2). WATER-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 increased by 3.00 ft (0.914 m) on Oct. 1978. REMARKS.--Records fair except those for estimated daily discharges, which are poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 109 e151 104 51 37 34 e40 39 94 68 76 63 2 101 e113 214 50 37 36 e63 39 87 71 52 86 3 94 e179 179 50 33 37 e70 38 68 65 58 143 4 89 e115 94 49 33 34 e45 39 64 64 52 97 5 85 e94 83 48 32 e35 e38 38 65 62 109 71 6 82 e93 77 48 33 e33 e35 e73 69 57 55 218 7 109 e91 75 46 31 e30 e32 e69 78 56 80 143 8 336 e90 72 46 30 e29 e70 e80 117 85 61 94 9 141 e88 70 46 30 e33 100 e50 153 57 46 145 10 116 e116 69 47 30 e36 122 e38 119 49 42 93 11 89 e95 68 46 29 e33 89 e34 138 46 173 117 12 92 97 67 44 30 e31 72 e33 113 43 127 81 13 88 96 66 44 29 e29 e63 e32 112 43 89 104 14 86 87 65 44 29 e28 e63 29 165 44 85 75 15 85 88 67 49 29 e27 65 28 344 47 71 68 16 225 103 65 47 30 e26 62 28 204 54 129 67 17 148 83 61 42 27 e25 58 28 157 62 82 62 18 e110 78 61 40 28 e25 55 28 120 44 71 59 19 e94 77 60 40 28 e40 52 27 179 40 85 107 20 e90 75 64 39 28 e75 48 27 138 59 69 71 21 85 73 60 47 28 e62 46 27 110 118 71 60 22 92 72 58 44 29 e61 43 28 167 92 110 57 23 81 75 59 38 29 e66 50 30 110 100 122 55 24 80 89 58 38 29 e70 55 26 93 62 77 119 25 140 76 56 37 42 e74 50 25 86 51 69 88 26 157 76 55 38 37 e50 47 26 79 47 64 74 27 300 226 54 41 31 e37 46 29 76 44 61 63 28 e165 105 54 41 34 e50 52 64 73 43 63 59 29 e208 83 53 36 --- e70 46 38 72 44 61 56 30 e150 79 52 35 --- e56 41 83 72 45 70 57 31 e138 --- 50 34 --- e45 --- 107 --- 40 73 --- TOTAL 3965 2963 2290 1345 872 1317 1718 1280 3522 1802 2453 2652 MEAN 128 98.8 73.9 43.4 31.1 42.5 57.3 41.3 117 58.1 79.1 88.4 MAX 336 226 214 51 42 75 122 107 344 118 173 218 MIN 80 72 50 34 27 25 32 25 64 40 42 55 AC-FT 7860 5880 4540 2670 1730 2610 3410 2540 6990 3570 4870 5260 CFSM 6.95 5.37 4.01 2.36 1.69 2.31 3.11 2.24 6.38 3.16 4.30 4.80 IN. 8.02 5.99 4.63 2.72 1.76 2.66 3.47 2.59 7.12 3.64 4.96 5.36 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1960 - 1999, BY WATER YEAR (WY) MEAN 81.0 68.0 42.7 30.0 26.1 25.2 36.1 56.4 44.5 36.3 47.0 78.0 MAX 195 159 121 71.0 50.8 71.2 142 193 117 65.7 110 208 (WY) 1990 1969 1966 1997 1996 1972 1969 1963 1999 1981 1979 1998 MIN 25.4 25.1 18.1 14.7 13.2 11.0 9.70 12.4 15.6 9.18 15.9 25.0 (WY) 1963 1995 1998 1998 1965 1984 1984 1977 1994 1994 1994 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1960 - 1999 ANNUAL TOTAL 24876 26179 ANNUAL MEAN 68.2 71.7 47.7 HIGHEST ANNUAL MEAN 71.7 1999 LOWEST ANNUAL MEAN 20.7 1994 HIGHEST DAILY MEAN 3260 Sep 22 344 Jun 15 3260 Sep 22 1998 LOWEST DAILY MEAN 10 Jan 30 25 Mar 17 5.4 Aug 4 1994 ANNUAL SEVEN-DAY MINIMUM 11 Jan 26 27 May 20 6.4 Jul 29 1994 INSTANTANEOUS PEAK FLOW 3120 Oct 27 23500 Sep 22 1998 INSTANTANEOUS PEAK STAGE 12.07 Oct 27 21.24 Sep 22 1998 INSTANTANEOUS LOW FLOW 24 May 25 5.4 Aug 4 1994 ANNUAL RUNOFF (AC-FT) 49340 51930 34530 ANNUAL RUNOFF (CFSM) 3.70 3.90 2.59 ANNUAL RUNOFF (INCHES) 50.29 52.93 35.20 10 PERCENT EXCEEDS 116 119 85 50 PERCENT EXCEEDS 45 62 33 90 PERCENT EXCEEDS 14 30 16 e Estimated 87 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 1,000 20 30 40 50 70 100 200 300 400 500 700 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 88 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR. WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1958 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED SEDIMENT DISCHARGE: January 1968 to current year. INSTRUMENTATION.--US D-49 sediment sampler since October 1968. Automatic sediment sampler since 1990 EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATIONS: Maximum daily mean,20,400 mg/L November 27,1968; minimum daily mean,4 mg/L May 20,p 1999. SEDIMENT LOADS: Maximum daily, 240,000 tons ( 218,000 tonnes) September 22, 1998, minimum daily, <0.01ton ( <0.01 tonne) several days during many years. EXTREMES FOR CURRENT YEAR 1998.-- SEDIMENT CONCENTRATIONS: Maximum daily mean,2,740 mg/L October 8,1998; minimum daily mean,4 mg/L May.20,1999. SEDIMENT LOADS: Maximum daily, 9,330 tons (8,460 tonnes) October 8,1998 minimum daily,0.30 ton ( 0.27 tonne) May 20,1999. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, INST. CIFIC WHOLE SOLVED CHEM- FECAL, CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) NOV 13... 1330 91 144 7.6 23.5 16 8.0 97 <10 3900 MAR 01... 1015 35 168 7.5 21.5 27 8.3 98 <10 K1000 MAY 25... 1155 26 156 7.9 27.5 2.1 8.5 112 <10 K16 AUG 11... 1205 40 162 8.1 27.6 4.0 7.2 95 <10 K80 ANC STREP- HARD- MAGNE- SODIUM POTAS- WATER TOCOCCI NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE FECAL, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- (COLS. (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED DATE PER AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L 100 ML) CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) (31679) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) NOV 13... 2000 50 12 4.8 7.2 .4 2.2 43 <1.0 9.1 MAR 01... 3000 -- -- -- -- -- -- 51 -- -- MAY 25... 88 59 14 5.7 8.1 .5 2.0 51 <1.0 12 AUG 11... K73 62 15 5.9 7.5 .4 2.0 52 -- 10 SOLIDS, RESIDUE CHLO- FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- RIDE, RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, DIS- DIS- SOLVED TUENTS, SOLVED DEG. C, NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL DATE (MG/L (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L AS CL) AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) (00940) (00950) (00955) (70301) (70302) (00530) (00615) (00630) (00610) (00605) NOV 13... 8.7 <.10 23 92 22.8 12 <.010 1.10 .030 -- MAR 01... -- -- -- -- -- 21 <.010 1.10 .020 -- MAY 25... 8.1 <.10 22 103 7.26 2 <.010 .520 .030 -- AUG 11... 8.2 <.10 26 107 11.6 9 <.010 .840 .020 .18 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 13... <.20 -- -- <.020 <1 <100 <10 <1 1 12 MAR 01... <.20 -- -- .670 -- -- -- -- -- -- MAY 25... <.20 -- -- <.020 <1 30 E20 <1 <1 <12 AUG 11... .20 1.0 4.6 <.020 -- -- -- -- -- -- 89 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 13... 590 <1 -- <.10 <1 <1 -- <.010 5 .03 MAR 01... -- -- -- -- -- -- -- -- -- -- MAY 25... 120 <1 18 .18 <1 <1 <40 <.010 <4 .02 AUG 11... -- -- -- -- -- -- -- -- -- -- SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 109 67 20 e151 e763 e512 104 220 73 2 101 53 14 e113 e371 e133 214 1460 1120 3 94 41 10 e179 e1520 e1760 179 1370 956 4 89 34 8.2 e115 e371 e513 94 132 34 5 85 33 7.6 e94 e92 e23 83 66 15 6 82 33 7.2 e93 e93 e23 77 43 9.0 7 109 403 239 e91 e95 e23 75 28 5.7 8 336 2740 9330 e90 e97 e24 72 19 3.8 9 141 692 361 e88 e99 e23 70 13 2.6 10 116 413 212 e116 e112 e45 69 10 1.9 11 89 311 75 e95 e29 e7.6 68 9 1.7 12 92 309 80 97 114 36 67 9 1.5 13 88 120 28 96 108 30 66 8 1.4 14 86 62 14 87 28 6.5 65 8 1.4 15 85 38 8.8 88 91 24 67 40 9.5 16 225 1780 3790 103 267 111 65 150 26 17 148 591 237 83 34 7.6 61 66 11 18 e110 e227 e85 78 24 5.1 61 29 4.8 19 e94 e87 e32 77 17 3.6 60 14 2.3 20 e90 e35 e11 75 16 3.2 64 16 2.8 21 85 25 5.6 73 16 3.2 60 22 3.6 22 92 105 28 72 17 3.3 58 28 4.4 23 81 120 26 75 24 4.7 59 20 3.1 24 80 50 11 89 34 8.2 58 12 1.8 25 140 766 674 76 48 9.9 56 7 1.1 26 157 1160 1400 76 51 10 55 7 1.0 27 300 2290 8150 226 1470 2860 54 7 1.0 28 e165 e844 e463 105 246 83 54 7 1.1 29 e208 e1930 e2440 83 41 9.2 53 9 1.3 30 e150 e668 e335 79 32 6.8 52 12 1.6 31 e138 e432 e200 --- --- --- 50 15 2.1 TOTAL 3965 --- 28302.4 2963 --- 6311.9 2290 --- 2305.5 90 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR.--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 51 24 3.3 37 24 2.4 34 74 7.1 2 50 40 5.4 37 23 2.3 36 59 6.4 3 50 55 7.3 33 17 1.5 37 56 5.7 4 49 34 4.4 33 11 1.0 34 27 2.5 5 48 18 2.4 32 8 .73 e35 e27 e2.5 6 48 11 1.4 33 9 .81 e33 e28 e2.6 7 46 13 1.6 31 10 .88 e30 e30 e2.8 8 46 17 2.0 30 12 .97 e29 e31 e3.0 9 46 20 2.4 30 13 1.0 e33 e33 e3.3 10 47 17 2.1 30 14 1.1 e36 e35 e3.5 11 46 13 1.6 29 15 1.2 e33 e37 e3.8 12 44 11 1.3 30 18 1.4 e31 e39 e4.1 13 44 10 1.2 29 21 1.7 e29 e41 e4.4 14 44 10 1.2 29 23 1.8 e28 e43 e4.7 15 49 44 7.6 29 16 1.3 e27 e45 e5.1 16 47 83 11 30 11 .90 e26 e31 e3.5 17 42 31 3.5 27 8 .61 e25 e50 e5.8 18 40 12 1.3 28 8 .62 e25 e10 e1.3 19 40 10 1.1 28 9 .65 e40 e11 e1.3 20 39 10 1.1 28 9 .68 e75 e20 e2.4 21 47 65 14 28 9 .72 e62 e17 e2.4 22 44 96 12 29 10 .75 e61 e17 e2.1 23 38 51 5.3 29 10 .77 e66 e18 e2.4 24 38 36 3.6 29 10 .79 e70 e34 e4.4 25 37 36 3.6 42 88 21 e74 e40 e5.4 26 38 38 3.9 37 60 6.1 e50 e40 e5.4 27 41 39 4.3 31 45 3.8 e37 e97 e14 28 41 34 3.7 34 62 6.1 e50 e97 e14 29 36 28 2.7 --- --- --- e70 e101 e15 30 35 24 2.2 --- --- --- e56 e101 e15 31 34 23 2.1 --- --- --- e45 e106 e16 TOTAL 1345 --- 120.6 872 --- 63.58 1317 --- 171.9 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) APRIL MAY JUNE 1 e40 e106 e16 39 21 2.3 94 308 121 2 e63 e106 e16 39 21 2.2 87 326 114 3 e70 e111 e18 38 20 2.1 68 178 33 4 e45 e111 e18 39 20 2.1 64 126 22 5 e38 e111 e18 38 20 2.1 65 104 18 6 e35 e115 e20 e73 e813 e959 69 86 16 7 e32 e115 e20 e69 e206 e76 78 148 34 8 e70 e92 e17 e80 e550 e464 117 731 405 9 100 451 204 e50 e140 e66 153 779 600 10 122 645 333 e38 e20 e9.6 119 375 136 11 89 247 63 e34 e21 e9.9 138 927 770 12 72 85 16 e33 e22 e10 113 232 71 13 e63 e92 e17 e32 e22 e7.2 112 78 24 14 e63 e105 e19 29 18 1.4 165 1130 1190 15 65 115 20 28 14 1.1 344 2590 8020 16 62 111 18 28 11 .82 204 1470 1450 17 58 106 16 28 9 .64 157 509 286 18 55 101 15 28 7 .49 120 254 85 19 52 97 14 27 5 .38 179 1130 1470 20 48 95 12 27 4 .30 138 341 151 21 46 93 11 27 5 .33 110 34 10 22 43 89 10 28 5 .40 167 1350 1450 23 50 133 26 30 6 .49 110 406 122 24 55 133 22 26 7 .49 93 226 57 25 50 122 19 25 9 .63 86 130 30 26 47 71 12 26 13 .89 79 75 16 27 46 76 10 29 17 1.4 76 43 8.8 28 52 92 16 64 346 193 73 25 5.1 29 46 97 12 38 76 8.6 72 19 3.7 30 41 36 3.9 83 377 199 72 15 3.0 31 --- --- --- 107 591 415 --- --- --- TOTAL 1718 --- 1031.9 1280 --- 2437.86 3522 --- 16721.6 91 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR.--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 68 12 2.3 76 392 292 63 155 27 2 71 10 1.9 52 291 44 86 245 82 3 65 9 1.6 58 212 40 143 1140 876 4 64 9 1.5 52 128 21 97 371 118 5 62 8 1.3 109 928 720 71 188 36 6 57 7 1.1 55 147 23 218 2210 4620 7 56 7 1.0 80 456 266 143 697 450 8 85 208 93 61 150 27 94 227 60 9 57 90 15 46 56 7.0 145 1390 1480 10 49 18 2.4 42 28 3.2 93 275 71 11 46 15 1.9 173 1600 2710 117 611 284 12 43 12 1.4 127 507 243 81 189 42 13 43 8 .95 89 325 79 104 414 152 14 44 9 1.1 85 287 70 75 166 35 15 47 35 5.0 71 211 40 68 22 4.1 16 54 79 17 129 1290 1260 67 18 3.3 17 62 162 50 82 171 39 62 28 4.7 18 44 74 8.8 71 138 27 59 30 4.8 19 40 41 4.5 85 245 68 107 639 518 20 59 178 55 69 70 13 71 148 30 21 118 920 1030 71 89 22 60 60 9.9 22 92 600 326 110 758 469 57 46 7.0 23 100 471 222 122 529 221 55 45 6.7 24 62 155 28 77 151 32 119 1120 1210 25 51 49 6.8 69 74 14 88 261 105 26 47 20 2.6 64 39 6.8 74 216 47 27 44 17 2.1 61 24 3.9 63 96 17 28 43 15 1.8 63 25 4.4 59 34 5.4 29 44 32 5.4 61 52 9.5 56 31 4.7 30 45 68 8.9 70 193 39 57 51 8.7 31 40 18 2.0 73 218 46 --- --- --- TOTAL 1802 --- 1902.35 2453 --- 6859.8 2652 --- 10319.3 YEAR 26179 76548.69 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) OCT 22... 1530 103 255 71 96 DEC 16... 1550 63 127 22 98 FEB 26... 0740 35 785 74 96 JUL 22... 0735 57 120 18 97 SEP 03... 1030 68 216 40 95 92 RIO GRANDE DE ARECIBO BASIN 50028000 RIO TANAMA NEAR UTUADO, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. SED. CHARGE, MENT, SUSP. SUSP. SUSP. INST. SEDI- DIS- FALL FALL FALL CUBIC MENT, CHARGE, DIAM. DIAM. DIAM. FEET SUS- SUS- % FINER % FINER % FINER DATE TIME PER PENDED PENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) JUN 10... 1020 101 1130 309 42 61 82 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) JUN 10... 95 99 99 100 100 100 100 93 RIO GRANDE DE ARECIBO BASIN 50028400 RIO TANAMA AT CHARCO HONDO, PR LOCATION.--Lat 18°24'52", long 66°42'52", Hydrologic Unit 21010002 on right bank near to an 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 mi2 (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 telmetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e183 e260 e240 e103 68 e60 e80 55 220 111 93 119 2 e170 e200 e450 e102 89 e62 e110 47 226 110 109 118 3 e160 e300 e380 e102 70 e64 e120 43 174 105 100 e299 4 e150 e200 e220 e100 67 e60 e80 48 218 98 102 e179 5 e145 e160 e180 e100 66 e62 e64 55 197 102 143 e140 6 e140 e159 e170 e96 64 e58 e56 186 130 94 113 e355 7 e200 e155 e165 e94 67 e52 56 134 114 91 88 e238 8 e560 e152 e160 e94 63 e52 57 157 201 105 122 e188 9 e240 e150 e151 e95 63 e60 71 158 404 126 78 e230 10 e200 e197 e150 e98 61 e80 190 90 407 93 71 e186 11 e152 e160 e147 e94 60 e60 141 70 351 89 235 e204 12 e154 e163 e139 e89 62 e56 76 63 318 113 179 e167 13 e150 e160 e137 e88 61 e54 65 66 216 110 129 e188 14 e148 e149 e132 e92 64 e52 63 65 294 84 105 e162 15 e141 e150 e133 e100 62 e50 59 e57 e596 86 115 e145 16 e380 e170 e132 e92 67 e47 58 e55 e362 84 176 e141 17 e240 e140 e122 e84 60 e47 55 e154 e304 106 127 e139 18 e180 e134 e122 e82 59 e56 55 e120 e262 91 105 e132 19 e160 e130 e123 e82 59 e90 54 e55 e320 77 122 e170 20 e150 e128 e125 e80 59 e130 50 e46 e232 85 145 e156 21 e149 e125 e111 e96 58 e107 48 e45 e189 221 105 e141 22 e160 e126 e112 e90 57 e107 47 e67 240 221 151 e133 23 e140 e130 e111 e78 e54 e115 45 e75 197 155 236 e130 24 e138 e150 e120 e78 e60 e120 89 e50 156 129 207 e183 25 e170 e130 e115 e76 e72 e123 67 e44 139 94 179 e171 26 e350 e180 e111 e80 e62 e90 55 e41 130 94 244 e160 27 e500 e380 e110 e90 e54 e66 70 e43 124 118 148 e148 28 e290 e170 e109 91 e60 e90 67 152 119 87 116 e137 29 e350 e139 e110 74 --- e120 105 235 115 79 125 e128 30 e250 e133 e105 66 --- e100 78 212 112 83 125 e126 31 e230 --- e101 65 --- e70 --- 267 --- 75 117 --- TOTAL 6730 5080 4793 2751 1768 2360 2231 2955 7067 3316 4210 5113 MEAN 217 169 155 88.7 63.1 76.1 74.4 95.3 236 107 136 170 MAX 560 380 450 103 89 130 190 267 596 221 244 355 MIN 138 125 101 65 54 47 45 41 112 75 71 118 AC-FT 13350 10080 9510 5460 3510 4680 4430 5860 14020 6580 8350 10140 CFSM 9.78 7.63 6.96 4.00 2.84 3.43 3.35 4.29 10.6 4.82 6.12 7.68 IN. 11.28 8.51 8.03 4.61 2.96 3.95 3.74 4.95 11.84 5.56 7.05 8.57 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1969 - 1999, BY WATER YEAR (WY) MEAN 165 133 82.2 60.9 50.8 44.3 66.0 125 95.6 67.4 83.7 142 MAX 335 260 219 167 106 76.1 141 371 236 120 168 448 (WY) 1990 1982 1982 1997 1996 1999 1986 1986 1999 1969 1998 1998 MIN 72.1 50.4 36.4 22.3 16.8 16.6 25.9 15.8 23.3 22.0 35.1 44.9 (WY) 1983 1995 1989 1989 1989 1988 1989 1989 1989 1989 1994 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1969 - 1999 ANNUAL TOTAL 48530 48374 ANNUAL MEAN 133 133 91.3 HIGHEST ANNUAL MEAN 133 1999 LOWEST ANNUAL MEAN 46.9 1994 HIGHEST DAILY MEAN 6400 Sep 22 596 Jun 15 6400 Sep 22 1998 LOWEST DAILY MEAN 23 Mar 23 41 May 26 4.2 May 28 1989 ANNUAL SEVEN-DAY MINIMUM 24 Mar 22 51 Apr 17 5.4 May 22 1989 INSTANTANEOUS PEAK FLOW 6440 Jun 15 15000 May 18 1985 INSTANTANEOUS PEAK STAGE 14.47 Jun 15 24.56 Sep 22 1998 ANNUAL RUNOFF (AC-FT) 96260 95950 66170 ANNUAL RUNOFF (CFSM) 5.99 5.97 4.11 ANNUAL RUNOFF (INCHES) 81.32 81.06 55.90 10 PERCENT EXCEEDS 228 230 180 50 PERCENT EXCEEDS 88 115 66 90 PERCENT EXCEEDS 31 57 29 e Estimated 94 RIO GRANDE DE ARECIBO BASIN 50028400 RIO TANAMA AT CHARCO HONDO, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 1,000 20 30 40 50 70 100 200 300 400 500 700 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 95 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 Río Tanamá, and 1.6 mi (2.6 km) southeast of Arecibo. WATER-DISCHARGE RECORDS DRAINAGE AREA.--200 mi2 (520 km2). PERIOD OF RECORD.--January 1963 to January 1965 (monthly measurements only), February 1965 to April 1969 (occasional measurements only), May 1969 to Sepetember 1983, October 1996 to current year. 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. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e2190 e271 e712 e360 464 400 170 252 1140 594 516 648 2 e1700 e245 e770 e300 372 341 155 288 905 373 459 571 3 e1780 e235 e2090 e260 403 177 574 271 822 591 557 762 4 e1370 e258 e1980 e500 350 288 584 331 941 591 438 788 5 e1600 e273 e1260 e620 254 351 600 153 1150 322 351 904 6 e1600 e299 e1100 e500 196 460 549 216 333 302 507 877 7 e1590 e142 e979 e420 148 327 477 583 528 486 534 1380 8 e1670 e435 e847 e260 183 151 392 443 294 435 659 1220 9 e4000 e1170 e536 e440 142 279 372 742 1370 273 439 1520 10 e1790 e1110 e841 e350 206 304 354 467 1970 420 464 1150 11 e1260 e898 e707 e460 173 164 275 607 1390 402 398 1020 12 e1080 e813 e285 e580 270 262 248 220 1170 391 370 976 13 e864 e1260 e238 e150 580 375 480 328 855 440 333 875 14 e524 e1210 e487 e190 372 317 362 372 738 417 274 1100 15 e454 e759 e307 e800 239 205 349 240 973 257 530 1340 16 e574 e914 e243 e240 255 278 167 319 1220 421 665 1300 17 e957 e924 e236 e500 306 164 124 255 1410 282 708 663 18 e610 e828 e253 e720 261 235 119 204 971 524 583 805 19 e409 e817 e427 e430 130 167 121 246 990 494 1110 842 20 e281 e948 e305 e96 123 532 193 193 664 484 572 648 21 e220 e563 e260 e230 169 440 210 155 818 591 258 734 22 e211 e416 e338 e349 120 541 178 246 488 720 334 763 23 e158 e720 e312 e209 108 630 264 135 763 504 880 791 24 e706 e729 e271 e186 105 355 196 297 624 338 829 607 25 e243 e692 e311 e363 342 196 226 344 603 283 739 503 26 e210 e419 e239 554 560 402 543 218 339 285 757 584 27 e172 e512 e580 335 712 262 365 111 261 284 673 802 28 e2410 e1080 e430 236 345 495 243 130 459 218 572 806 29 e1030 e944 e370 175 --- 602 473 305 527 287 376 600 30 e542 e675 e340 156 --- 570 402 305 433 417 546 679 31 e338 --- e270 149 --- 283 --- 460 --- 618 723 --- TOTAL 32543 20559 18324 11118 7888 10553 9765 9436 25149 13044 17154 26258 MEAN 1050 685 591 359 282 340 326 304 838 421 553 875 MAX 4000 1260 2090 800 712 630 600 742 1970 720 1110 1520 MIN 158 142 236 96 105 151 119 111 261 218 258 503 AC-FT 64550 40780 36350 22050 15650 20930 19370 18720 49880 25870 34020 52080 CFSM 5.25 3.43 2.96 1.79 1.41 1.70 1.63 1.52 4.19 2.10 2.77 4.38 IN. 6.05 3.82 3.41 2.07 1.47 1.96 1.82 1.76 4.68 2.43 3.19 4.88 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1969 - 1999, BY WATER YEAR (WY) MEAN 807 718 520 353 296 317 374 541 475 383 448 714 MAX 1577 1388 1327 651 425 627 641 1192 1220 854 1269 1866 (WY) 1971 1978 1982 1997 1997 1972 1983 1980 1979 1979 1979 1979 MIN 404 201 150 155 152 122 196 188 139 189 218 271 (WY) 1983 1998 1998 1973 1974 1998 1975 1977 1977 1997 1974 1997 SUMMARY STATISTICS FOR 1999 WATER YEAR WATER YEARS 1969 - 1999 ANNUAL TOTAL 201791 ANNUAL MEAN 553 504 HIGHEST ANNUAL MEAN 691 1979 LOWEST ANNUAL MEAN 290 1974 HIGHEST DAILY MEAN 4000 Oct 9 15900 Aug 31 1979 LOWEST DAILY MEAN 96 Jan 20 56 Mar 28 1998 ANNUAL SEVEN-DAY MINIMUM 145 Feb 18 67 Mar 18 1998 INSTANTANEOUS PEAK FLOW Not determined Oct 28 Not determined Sep 22 1998 INSTANTANEOUS PEAK STAGE Not determined Oct 28 19.28 Sep 22 1998 INSTANTANEOUS LOW FLOW 50 Feb 26 1974 ANNUAL RUNOFF (AC-FT) 400300 365400 ANNUAL RUNOFF (CFSM) 2.76 2.52 ANNUAL RUNOFF (INCHES) 37.53 34.27 10 PERCENT EXCEEDS 1090 969 50 PERCENT EXCEEDS 435 356 90 PERCENT EXCEEDS 188 136 e Estimated 96 RIO GRANDE DE ARECIBO BASIN 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAMBALACHE, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 97 RIO GRANDE DE ARECIBO BASIN 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAMBALACHE, 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 Tanamá , and 1.6 mi (2.6 km) southeast of Arecibo. DRAINAGE AREA.--200 mi2 (520 km2), approximately. PERIOD OF RECORD.--Water years 1963-66, 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 05... 1030 E950 209 7.6 24.5 110 6.9 82 <10 2600 3200 MAR 03... 1045 211 300 7.7 23.5 7.0 8.1 95 22 250 200 MAY 06... 1215 141 330 8.0 27.5 10 9.7 123 <10 330 110 AUG 09... 0940 386 238 7.5 27.0 15 7.3 92 <10 2200 2000 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 05... 85 26 4.9 7.4 .3 2.6 72 <1.0 10 10 MAR 03... -- -- -- -- -- -- 140 -- -- -- MAY 06... 150 49 6.5 9.7 .3 1.7 140 <1.0 12 12 AUG 09... 100 31 6.2 8.7 .4 2.1 75 -- 11 9.7 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 05... .10 18 122 -- 90 -- <.010 1.50 .040 .54 MAR 03... -- -- -- -- 11 -- <.010 .980 .030 -- MAY 06... <.10 14 188 71.5 5 .590 .010 .600 .030 -- AUG 09... <.10 20 133 138 39 .460 .010 .470 .040 .31 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 05... .58 2.1 9.2 .160 <1 <100 20 <1 4 22 MAR 03... <.20 -- -- <.020 -- -- -- -- -- -- MAY 06... <.20 -- -- E.020 <1 60 40 <1 <1 <12 AUG 09... .35 .82 3.6 .050 -- -- -- -- -- -- 98 RIO GRANDE DE ARECIBO BASIN 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAMBALACHE, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 05... 4300 3 180 <.10 <1 <1 20 <.010 <4 <.02 MAR 03... -- -- -- -- -- -- -- -- -- -- MAY 06... 350 <1 32 <.10 <1 <1 <40 <.010 <4 <.04 AUG 09... -- -- -- -- -- -- -- -- -- -- de de Río Río Río Río Río Río Río Río Lago de Matrullas Lago Guineo Caño Tiburones Grande Grande Cialitos Toro Negro Manatí Manatí Matrullas Sana Muertos Bauta Orocovis Laguna Tortuguero QUALITY-OF-WATER STATION AND NUMBER 0340 0307 210 032290 EXPLANATION WELL AND WELL NUMBER LAKE-ELEVATION STATION AND NUMBER SURFACE-WATER STATION AND NUMBER CAÑO TIBURONES FLOW DIRECTION TUNNEL FLOW DIRECTION DRAINAGE BASIN BOUNDARY TOWN OR CITY Figure 14. Río Grande de Manatí basin. 99 BARCELONETA MANATÍ VEGA BAJA VEGA ALTA ATLANTIC OCEAN JAYUYA OROCOVIS VILLALBA BARRANQUITAS CIALES MOROVIS COROZAL Basin area PUERTO RICO FLORIDA 0 0 1 1 2 2 3 3 4 4 5 MILES 5 KILOMETERS 030460 0307 0312 0350 035950 0355 0381 0382 0340 210 1077 1076 206 207 166 032290 032590 100 RIO GRANDE DE MANATI BASIN 50030460 RIO OROCOVIS AT OROCOVIS, PR LOCATION.--Lat 18°13'25", long 66°23'34", Hydrologic Unit 21010001, on right bank, 0.4 mi (0.6 km) south of junction of Highways 155 and 156 in Orocovis, 2.1 mi (3.38 km) upstream from Río Botijas, and 250 ft (76 m) upstream from bridge on Highway 599. DRAINAGE AREA.--5.03 mi2 (13.03 km2). 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 satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 23 37 e100 4.0 7.1 11 1.2 e1.5 e36 2.5 1.0 e25 2 16 e81 e124 3.9 6.1 7.0 13 e1.3 e100 11 1.0 e37 3 15 56 e93 3.8 4.2 4.4 66 e1.4 e28 3.9 8.1 e41 4 13 29 e46 3.6 4.0 3.3 14 e1.3 e7.0 2.6 2.3 e27 5 12 17 e23 3.4 3.7 2.9 3.6 e1.6 e6.3 2.6 1.9 e19 6 11 12 e15 3.4 3.4 3.0 2.3 e1.4 e4.9 2.6 1.8 e159 7 11 9.8 e10 3.2 3.5 3.1 2.1 e2.0 e3.9 2.0 1.7 e35 8 10 8.5 e7.9 3.2 3.3 2.9 2.1 e41 e26 3.9 1.6 e21 9 9.6 9.9 e6.6 3.3 3.4 2.8 1.9 e7.8 e47 4.4 1.7 e34 10 9.2 10 e5.8 3.4 3.3 2.5 1.4 e3.4 e104 2.5 1.4 e20 11 8.9 8.9 e5.6 3.3 3.3 2.3 1.5 e2.4 e45 2.4 1.5 e17 12 9.4 e77 5.3 3.1 4.4 2.1 1.5 e2.0 e18 1.7 1.4 e14 13 8.8 62 5.2 16 3.8 2.0 1.5 e1.7 e9.7 2.2 1.4 e114 14 8.6 108 4.8 6.2 3.6 1.8 1.4 e1.5 e6.8 2.7 1.8 e59 15 8.8 e54 4.8 15 3.9 e1.6 1.1 e1.4 e6.1 2.3 1.5 e31 16 7.8 e23 4.5 6.3 4.9 e1.5 1.1 e1.4 e6.4 1.7 1.4 e24 17 7.6 e15 4.5 5.4 3.7 e1.6 1.1 e1.4 e8.8 1.3 2.1 e20 18 7.5 e11 4.3 3.9 3.5 e1.5 1.1 e1.3 e6.3 1.2 2.6 e20 19 7.4 e10 4.2 3.6 3.4 e5.9 1.1 e1.3 e5.1 1.4 2.3 e74 20 17 e9.5 5.5 3.5 3.7 2.7 1.1 e1.3 e5.1 1.5 1.9 e51 21 13 e8.4 4.4 3.3 3.7 1.6 1.1 e1.3 e4.8 1.4 2.1 e23 22 43 e7.3 4.1 3.3 3.9 1.4 1.1 e1.3 e4.4 1.0 e12 e24 23 17 e8.7 4.3 3.2 3.9 2.2 1.1 e1.3 e4.1 1.1 e4.6 e23 24 11 e8.0 4.1 3.2 3.6 1.8 1.1 e1.2 3.2 1.1 e2.4 e20 25 11 e6.8 3.9 3.4 3.7 3.8 5.3 e1.2 3.2 1.3 e2.1 e18 26 43 e6.2 3.8 3.4 3.4 2.8 2.2 e1.2 3.2 1.0 e11 e27 27 e180 e9.2 3.7 3.4 2.5 1.7 e1.3 e1.2 2.7 .99 e9.4 e43 28 152 e42 3.8 19 3.8 1.6 e1.2 e1.2 2.7 .98 e5.0 e32 29 66 e17 20 4.8 --- 1.4 e2.2 e1.2 2.5 1.1 e75 e33 30 75 e13 5.3 3.9 --- 1.3 e2.1 e1.9 2.4 1.2 e80 e39 31 111 --- 4.5 3.8 --- 1.2 --- e1.4 --- 1.1 e45 --- TOTAL 943.6 775.2 541.9 156.2 108.7 86.7 138.8 92.8 513.6 68.67 289.0 1124 MEAN 30.4 25.8 17.5 5.04 3.88 2.80 4.63 2.99 17.1 2.22 9.32 37.5 MAX 180 108 124 19 7.1 11 66 41 104 11 80 159 MIN 7.4 6.2 3.7 3.1 2.5 1.2 1.1 1.2 2.4 .98 1.0 14 AC-FT 1870 1540 1070 310 216 172 275 184 1020 136 573 2230 CFSM 6.05 5.14 3.48 1.00 .77 .56 .92 .60 3.40 .44 1.85 7.45 IN. 6.98 5.73 4.01 1.16 .80 .64 1.03 .69 3.80 .51 2.14 8.31 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1981 - 1999, BY WATER YEAR (WY) MEAN 17.0 7.99 5.80 5.99 4.13 1.82 5.32 14.0 5.19 3.31 4.49 25.8 MAX 58.0 25.8 17.5 34.3 15.7 3.07 21.0 45.9 17.1 9.07 12.3 83.0 (WY) 1990 1999 1999 1992 1996 1996 1993 1995 1999 1996 1989 1998 MIN 1.95 .93 .53 .77 .96 .90 .93 .86 .88 .88 1.03 .88 (WY) 1994 1998 1998 1995 1995 1994 1995 1997 1994 1994 1982 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1981 - 1999 ANNUAL TOTAL 6486.30 4839.17 ANNUAL MEAN 17.8 13.3 8.33 HIGHEST ANNUAL MEAN 13.3 1999 LOWEST ANNUAL MEAN 1.49 1994 HIGHEST DAILY MEAN 1130 Sep 22 180 Oct 27 1570 Sep 10 1996 LOWEST DAILY MEAN .33 Jan 31 .98 Jul 28 .20 Oct 4 1992 ANNUAL SEVEN-DAY MINIMUM .40 Jan 28 1.1 Jul 26 .33 Oct 11 1992 INSTANTANEOUS PEAK FLOW 2330 Sep 6 8890 Sep 10 1996 INSTANTANEOUS PEAK STAGE 11.54 Sep 6 17.38 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 12870 9600 6040 ANNUAL RUNOFF (CFSM) 3.53 2.64 1.66 ANNUAL RUNOFF (INCHES) 47.97 35.79 22.51 10 PERCENT EXCEEDS 41 37 13 50 PERCENT EXCEEDS 2.5 3.9 2.0 90 PERCENT EXCEEDS .60 1.3 .81 e Estimated 101 RIO GRANDE DE MANATI BASIN 50030460 RIO OROCOVIS AT OROCOVIS, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 0.1 1,000 0.2 0.5 1 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 102 RIO GRANDE DE MANATI BASIN 50030700 RIO OROCOVIS NEAR OROCOVIS, PR WATER-QUALITY RECORDS LOCATION.--Lat 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 mi2 (26.2 km2). PERIOD OF RECORD.--Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 27... 1010 38 216 7.9 23.0 27 7.7 94 <10 30000 8200 FEB 17... 1550 10 303 8.3 22.5 6.3 8.5 104 <10 360 K120 JUN 02... 1115 10 270 7.8 24.0 110 7.6 95 <10 K6300 5900 AUG 25... 1350 9.1 301 8.4 27.9 47 7.3 100 <10 4700 560 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) OCT 27... 84 19 8.9 11 .5 2.0 77 <1.0 8.4 14 FEB 17... -- -- -- -- -- -- 120 -- -- -- JUN 02... 110 27 10 12 .5 2.0 100 <1.0 9.0 14 AUG 25... 120 30 11 12 .5 1.9 120 -- 9.1 16 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) OCT 27... .10 27 137 14.0 15 -- <.010 1.90 .150 1.1 FEB 17... -- -- -- -- 8 .887 .013 .900 .050 .25 JUN 02... .12 27 161 4.48 68 -- <.010 1.50 .030 -- AUG 25... .13 33 185 4.52 74 1.59 .010 1.60 .040 .24 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) OCT 27... 1.3 3.2 14 .370 <1 <100 30 <1 2 <10 FEB 17... .30 1.2 5.3 .120 -- -- -- -- -- -- JUN 02... E.34 -- -- E.160 <1 60 40 <1 4 E10 AUG 25... .28 1.9 8.3 .210 -- -- -- -- -- -- 103 RIO GRANDE DE MANATI BASIN 50030700 RIO OROCOVIS NEAR OROCOVIS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) OCT 27... 780 <1 36 <.10 <1 2 10 <.010 <4 <.02 FEB 17... -- -- -- -- -- -- -- -- -- -- JUN 02... 2000 <1 63 <.10 <1 <1 <40 <.010 5 <.08 AUG 25... -- -- -- -- -- -- -- -- -- -- 104 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR LOCATION.--Lat 18°17'45", long 66°24'47", Hydrologic Unit 21010001, on right bank , 0.1 mi (0.2 km) downstream from Quebrada Perchas, 0.8 mi (1.3 km) upstream from Río Sana Muerto, and 2.2 mi (3.5 km) south of Morovis. DRAINAGE AREA.--55.2 mi2 (143.0 km2). 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 1000 ft (305 m) above the station, influences low-flow discharges. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 209 e205 e282 112 e96 102 36 e48 e229 e54 59 e66 2 169 e191 e800 107 e122 175 63 e46 e240 e149 61 e126 3 152 e208 e450 107 e95 99 135 e40 e152 e110 68 e204 4 137 e185 e300 101 e74 e60 140 e43 e110 e69 58 e150 5 134 e156 e220 98 e84 e52 57 e77 e98 e257 56 e105 6 125 e145 e190 98 e74 e48 43 e259 e91 e167 53 e209 7 142 e145 e175 92 e78 e47 39 e214 e106 e74 52 e500 8 132 e139 e165 89 e70 e46 43 e272 e320 e127 54 e250 9 117 e140 e160 88 e81 e45 44 e198 e737 e144 53 e350 10 109 e151 e155 92 e76 e58 36 e126 e449 e115 53 e250 11 104 e142 e148 100 e69 e56 38 e101 e192 e103 54 e180 12 111 e142 e144 87 e67 e70 36 e88 e140 e93 52 e150 13 102 e320 e144 82 e69 e75 34 e72 e110 e76 50 e200 14 105 e220 e142 98 e61 e52 33 e59 e85 e75 51 e450 15 99 e190 e140 99 e64 e47 32 e50 e75 e95 53 e270 16 93 e180 e139 117 e68 e45 32 e45 e70 e85 53 e200 17 92 e153 e137 86 e56 e44 30 e42 e170 e84 e83 e151 18 90 e148 e136 79 57 43 29 e43 e100 e81 e75 e163 19 87 e144 e136 75 57 48 29 e41 e75 e62 e58 e577 20 95 e140 e144 73 55 52 28 e35 e66 e62 e70 e682 21 93 e142 e141 72 55 42 27 e31 e62 e60 e60 e187 22 139 e138 e137 70 55 41 26 e31 e60 58 e85 e151 23 154 e143 e133 75 54 50 27 e38 e57 57 e146 e135 24 106 e148 139 74 53 45 26 e44 e56 57 e115 e130 25 119 e140 130 70 53 42 66 e44 e57 57 e67 e125 26 223 e141 123 75 57 43 e95 e38 e58 55 e116 e120 27 e443 e154 117 79 51 39 e68 e74 e57 53 e126 e140 28 435 e177 111 e182 53 38 e67 e89 e58 53 e69 e176 29 e302 e166 211 e123 --- 37 e56 e67 e56 53 e105 e130 30 e197 e161 142 e89 --- 38 e54 e97 e56 72 e129 e148 31 e232 --- 121 e82 --- 39 --- e154 --- 73 e84 --- TOTAL 4847 4954 5812 2871 1904 1718 1469 2606 4192 2730 2268 6675 MEAN 156 165 187 92.6 68.0 55.4 49.0 84.1 140 88.1 73.2 222 MAX 443 320 800 182 122 175 140 272 737 257 146 682 MIN 87 138 111 70 51 37 26 31 56 53 50 66 AC-FT 9610 9830 11530 5690 3780 3410 2910 5170 8310 5410 4500 13240 CFSM 2.83 2.99 3.40 1.68 1.23 1.00 .89 1.52 2.53 1.60 1.33 4.03 IN. 3.27 3.34 3.92 1.93 1.28 1.16 .99 1.76 2.83 1.84 1.53 4.50 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1965 - 1999, BY WATER YEAR (WY) MEAN 150 140 108 80.5 63.6 62.9 103 155 61.8 46.0 53.5 113 MAX 1037 491 522 228 179 226 412 915 173 157 435 432 (WY) 1971 1971 1966 1997 1969 1972 1969 1985 1987 1979 1979 1996 MIN 24.0 11.4 8.65 10.4 15.3 12.7 8.80 15.7 6.75 5.54 9.70 6.87 (WY) 1978 1995 1995 1995 1994 1984 1995 1994 1994 1994 1984 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1965 - 1999 ANNUAL TOTAL 38131.3 42046 ANNUAL MEAN 104 115 94.4 HIGHEST ANNUAL MEAN 248 1971 LOWEST ANNUAL MEAN 24.2 1994 HIGHEST DAILY MEAN 7010 Sep 22 800 Dec 2 17100 May 18 1985 LOWEST DAILY MEAN 6.1 Feb 1 26 Apr 22 3.5 May 1 1995 ANNUAL SEVEN-DAY MINIMUM 6.5 Jan 27 27 Apr 18 4.0 Jul 22 1994 INSTANTANEOUS PEAK FLOW 3630 Jun 9 48000 May 18 1985 INSTANTANEOUS PEAK STAGE 6.16 Jun 9 17.89 May 18 1985 ANNUAL RUNOFF (AC-FT) 75630 83400 68410 ANNUAL RUNOFF (CFSM) 1.89 2.09 1.71 ANNUAL RUNOFF (INCHES) 25.70 28.34 23.24 10 PERCENT EXCEEDS 183 200 170 50 PERCENT EXCEEDS 34 89 48 90 PERCENT EXCEEDS 11 43 20 e Estimated 105 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 1,000 20 30 40 50 70 100 200 300 400 500 700 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 106 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR. WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 27... 1215 179 200 7.8 25.0 250 7.7 95 19 22000 28000 FEB 17... 1230 58 277 8.4 23.0 8.5 10.2 120 12 360 K30 MAY 28... 1200 69 192 7.1 27.5 640 6.8 88 27 50000 40000 AUG 25... 1115 39 250 7.8 28.2 61 7.7 101 <10 2300 350 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) OCT 27... 73 17 7.6 9.1 .5 3.2 64 <1.0 8.8 13 FEB 17... -- -- -- -- -- -- 110 -- -- -- MAY 28... 65 15 6.6 8.7 .5 2.7 59 E1.0 9.2 12 AUG 25... 94 22 9.4 10 .5 2.2 89 -- 9.5 13 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) OCT 27... .18 20 116 56.1 260 1.66 .042 1.70 .080 1.0 FEB 17... -- -- -- -- 9 -- <.010 .790 .030 .27 MAY 28... .13 14 105 19.4 1310 1.16 .040 1.20 .090 -- AUG 25... .12 26 146 15.5 58 1.08 .020 1.10 .070 .44 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) OCT 27... 1.1 2.8 12 .320 <1 <100 30 <1 12 31 FEB 17... .30 1.1 4.8 .080 -- -- -- -- -- -- MAY 28... E2.6 -- -- E.670 2 200 40 <1 57 90 AUG 25... .51 1.6 7.1 .110 -- -- -- -- -- -- 107 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) OCT 27... 9000 2 310 <.10 <1 <1 20 <.010 <4 <.02 FEB 17... -- -- -- -- -- -- -- -- -- -- MAY 28... 27000 8 1000 .16 <1 <1 50 <.010 <4 <.16 AUG 25... -- -- -- -- -- -- -- -- -- -- 108 RIO GRANDE DE MANATI BASIN 50032290 LAGO EL GUINEO AT DAMSITE NEAR VILLALBA, PR LOCATION.--Lat 18°09'41", long 66°31'36", Hydrologic Unit 21010001, at damsite on Río Toro Negro, 3.0 mi (4.8 km) northwest from Villalba 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 mi2 (4.25 km2). 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 Río 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.1, 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 2,960 ft (902 m) above mean sea level and a design capacity of 7,000 ft3/s. 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 2,964.40 ft (903.55 m), Sept, 22 1998; minimun elevation, 2,919.79 ft (899.95 m), May 27, 1988. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 2,961.79 ft (902.71 m), Apr.29; minimun elevation, 2,939.99 ft (896.06m), Aug.13. 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 2,872 0 2,950 1,308 2,919 361 2,961 1,852 2,925 491 2,966 2,180 2,943 1,029 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 A 2960.77 2960.64 2960.65 2960.68 2960.52 2959.57 2960.70 2955.11 2955.95 2946.58 2951.39 2 A 2960.76 2960.72 2960.67 2960.66 2960.55 2959.62 2960.70 2954.91 2956.12 2946.02 2952.03 3 A 2960.76 2960.71 2960.67 2960.59 2960.44 2960.10 2960.37 2954.71 2956.20 2945.33 2952.56 4 A 2960.76 2960.71 2960.57 2960.63 2960.32 2960.17 2960.03 2954.68 2955.41 2944.73 2953.35 5 A 2960.77 2960.70 2960.32 2960.56 2960.20 2959.94 2959.69 2957.48 2955.32 2944.85 2953.69 6 A 2960.76 2960.70 2960.40 2960.59 2960.20 2959.63 2959.34 2957.68 2954.74 2944.21 2955.59 7 A 2960.81 2960.69 2960.23 2960.62 2960.26 2959.33 2959.02 A 2954.49 2944.23 2956.43 8 A 2960.74 2960.70 2960.21 2960.53 2960.16 2959.49 2959.21 A 2954.05 2944.25 2957.05 9 A 2960.51 2960.65 2960.29 2960.44 2960.15 2960.84 2959.29 A 2953.44 2943.58 2959.01 10 A 2960.61 2960.64 2960.42 2960.47 2960.04 2960.79 2958.95 2956.01 2953.50 2942.91 2959.46 11 A 2960.73 2960.61 2960.50 2960.53 2959.93 2960.78 2958.77 2956.33 2953.55 2942.34 2959.86 12 A 2960.82 2960.68 2960.40 2960.57 2959.83 2960.45 2958.45 2956.37 2953.28 2941.58 2960.44 13 A 2960.70 2960.69 2960.46 2960.63 2959.84 2960.22 2958.60 2956.58 2952.93 2941.17 2960.99 14 2944.30 2960.78 2960.62 2960.28 2960.73 2959.85 2959.81 2958.39 2956.09 2952.54 2942.45 2960.82 15 2944.88 2960.78 2960.61 2960.29 2960.67 2959.72 2959.38 2958.48 2955.98 2952.22 2942.59 2960.79 16 2945.36 2960.71 2960.57 2960.45 2960.66 2959.59 2959.03 2958.56 2955.71 2951.83 2943.25 2960.77 17 2945.81 2960.62 2960.55 2960.30 2960.60 2959.46 2958.72 2958.20 2955.50 2951.86 2943.52 2960.74 18 2946.21 2960.74 2960.52 2960.38 2960.48 2959.45 2958.76 2957.90 2955.45 2951.88 2943.71 2960.74 19 2946.57 2960.74 2960.66 2960.38 2960.38 2960.49 2958.81 2957.51 2955.68 2951.53 2944.24 2960.80 20 2946.95 2960.73 2960.68 2960.37 2960.41 2960.55 2958.33 2957.03 2955.85 2951.25 2944.46 2960.81 21 2947.33 2960.72 2960.60 2960.43 2960.43 2960.83 2957.84 2956.80 A 2950.56 2944.63 2960.72 22 2950.20 2960.72 2960.55 2960.41 2960.32 2960.70 2957.58 2956.45 A 2949.86 2945.28 2960.71 23 2950.83 2960.63 2960.54 2960.46 2960.30 2960.60 2959.14 2956.50 A 2949.50 2945.47 2960.72 24 2951.31 2960.59 2960.54 2960.51 2960.28 2960.52 2959.35 2956.04 A 2949.52 2945.56 2960.71 25 2951.74 2960.56 2960.62 2960.48 2960.30 2960.50 2959.80 2955.70 A 2949.02 2945.62 2960.70 26 2952.99 2960.70 2960.66 2960.54 2960.38 2960.37 2959.92 2955.16 A 2948.72 2945.91 2960.70 27 2957.00 2960.72 2960.67 2960.59 2960.45 2960.40 2960.02 2954.77 A 2947.95 2946.00 2960.69 28 2958.43 2960.75 2960.64 2960.66 2960.49 2960.44 2959.99 2954.58 A 2947.70 2946.49 2960.73 29 2959.20 2960.70 2960.67 2960.64 A 2960.11 2960.80 2954.62 A 2947.00 2950.60 2960.70 30 2959.93 2960.61 2960.67 2960.65 A 2959.81 2960.71 2954.72 2955.84 2946.29 2950.99 2960.70 31 2960.62 --- 2960.57 2960.65 --- 2959.57 --- 2955.30 --- 2946.31 2951.22 --- MAX --- 2960.82 2960.72 2960.67 2960.73 2960.83 2960.84 2960.70 --- 2956.20 2951.22 2960.99 MIN --- 2960.51 2960.52 2960.21 2960.28 2959.45 2957.58 2954.58 --- 2946.29 2941.17 2951.39 A No gage-height record 109 RIO GRANDE DE MANATI BASIN 50032590 LAGO DE MATRULLAS AT DAMSITE NEAR OROCOVIS, PR LOCATION.--Lat 18°12'46", long 66°28'50", Hydrologic Unit 21010001, in shelter house at damsite, and 5.8 mi (9.3 km) southwest of Orocovis. DRAINAGE AREA.--4.46 mi2 (11.55 km2). ELEVATION RECORDS PERIOD OF RECORD.--May 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 hm3) 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 Díaz 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, 2,417.37 ft (736.81 m),Sept. 6; minimum elevation, 2,413.23 ft (735.55 m) May 28. 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 2,338 2 2,399 1,845 2,360 302 2,420 3,331 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 2415.43 A A A 2415.36 2415.22 2413.85 2415.01 2414.69 2414.83 2414.58 2415.26 2 2415.37 A A A 2415.22 2415.32 2413.98 2415.14 2415.42 2414.86 2414.44 2415.27 3 2415.41 2415.42 A A 2415.14 2415.14 2415.39 2415.00 2415.21 2415.06 2414.33 2415.45 4 2415.24 2415.40 A A 2415.10 2415.01 2415.35 2414.85 2415.10 2414.89 2414.51 2415.23 5 2415.05 2415.40 A A 2415.04 2414.89 A 2414.74 2415.32 2415.10 2414.48 2415.40 6 2415.04 2415.39 A A 2414.89 2414.89 A 2414.67 2415.30 2414.96 2414.38 2415.82 7 2415.37 2415.38 A A 2415.08 2415.03 A 2414.53 2415.13 2414.86 2414.51 2415.43 8 2415.52 2415.38 A A 2414.98 2414.89 A 2415.24 2415.50 2414.87 2414.62 2415.54 9 2415.38 2415.40 A A 2414.90 2414.84 A 2415.28 2415.38 2414.74 2414.47 2415.75 10 2415.38 2415.38 A A 2414.82 2414.73 A 2415.13 2415.54 2414.93 2414.30 2415.49 11 2415.37 2415.40 A A 2414.81 2414.60 A 2415.00 2415.55 2415.11 2414.12 2415.51 12 A 2415.68 A A 2414.71 2414.55 A 2414.87 2415.41 2415.01 2413.88 2415.41 13 A 2415.44 A A 2414.89 2414.70 A 2414.73 2415.40 2414.96 2413.85 2415.90 14 A 2415.62 2415.40 A 2415.13 2414.83 A 2414.75 2415.21 2414.89 2415.49 2415.64 15 A 2415.48 2415.40 A 2415.31 2414.68 A 2414.86 2415.28 2414.84 2415.36 2415.64 16 A 2415.43 2415.39 A 2415.16 2414.55 2414.10 2414.98 2415.43 2414.75 2415.22 2415.51 17 A 2415.42 2415.38 A 2415.05 2414.40 2414.22 2414.81 2415.64 2414.92 2415.10 2415.47 18 A 2415.38 2415.43 A 2414.95 2414.24 2414.32 2414.64 2415.33 2415.07 2414.95 2415.33 19 A 2415.41 2415.45 A 2414.83 2414.24 2414.43 2414.48 2415.40 2415.23 2414.50 2415.87 20 A 2415.37 2415.46 A 2414.99 2414.39 2414.19 2414.31 2415.43 2415.07 2414.08 2415.81 21 A 2415.39 2415.39 2414.93 2415.14 2414.54 2413.96 2414.14 2415.30 2414.91 2414.10 2415.61 22 A 2415.40 2415.37 2414.87 2415.09 2414.73 2413.76 2414.02 2415.26 2414.77 2414.80 2415.52 23 A 2415.38 2415.37 2415.08 2415.01 2414.60 2413.53 2414.15 2415.15 2414.61 2414.83 2415.56 24 A 2415.34 2415.42 2415.27 2414.91 2414.47 2413.69 2413.99 2415.12 2414.75 2414.75 2415.51 25 A 2415.33 2415.44 2415.16 2414.88 2414.39 2413.97 2413.81 2415.08 2414.66 2414.62 2415.48 26 A 2415.38 2415.44 2415.29 2414.80 2414.25 2413.84 2413.64 2415.29 2414.79 2415.63 2415.55 27 A A 2415.44 2415.17 2414.97 2414.37 2413.66 2413.46 2415.34 2414.76 2415.29 2415.50 28 A A A 2415.25 2415.13 2414.49 2413.48 2413.28 2415.16 2414.64 2415.37 2415.50 29 A A A 2415.15 --- 2414.33 2414.88 2413.38 2415.04 2414.48 2415.94 2415.49 30 A A A 2415.31 --- 2414.17 2414.86 2413.49 2414.97 2414.32 2415.38 2415.56 31 A --- A 2415.33 --- 2414.02 --- 2413.62 --- 2414.45 2415.30 --- MAX --- --- --- --- 2415.36 2415.32 --- 2415.28 2415.64 2415.23 2415.94 2415.90 MIN --- --- --- --- 2414.71 2414.02 --- 2413.28 2414.69 2414.32 2413.85 2415.23 A No gage-height record 110 RIO GRANDE DE MANATI BASIN 50034000 RIO BAUTA NEAR OROCOVIS, 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 mi2 (43.3 km2). 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e114 116 153 30 27 29 15 15 108 15 12 38 2 e81 163 235 29 31 31 35 14 257 33 14 53 3 e68 151 179 28 24 20 175 14 125 21 21 97 4 e60 99 112 27 22 18 99 13 52 23 19 53 5 e55 66 81 27 21 17 33 15 45 25 17 65 6 e50 53 66 27 20 16 23 14 37 20 14 e192 7 e56 47 59 26 19 16 19 18 30 17 13 e78 8 e72 42 52 25 19 16 17 123 85 24 12 e62 9 e77 45 48 25 18 17 19 52 150 25 12 e72 10 e52 48 45 25 18 17 17 27 259 19 12 e62 11 e44 44 44 25 18 16 16 19 154 17 12 e57 12 e43 126 42 24 18 23 15 17 79 17 12 e53 13 e44 169 40 59 18 23 15 16 49 17 13 e137 14 e42 194 39 43 19 17 15 15 34 e19 30 e101 15 e40 152 37 66 20 16 14 14 27 e19 17 e76 16 e34 83 36 69 22 14 14 14 28 18 11 e67 17 e30 60 35 51 18 14 14 14 47 17 11 e63 18 e28 50 34 32 17 14 14 13 37 16 11 e61 19 e27 46 33 26 17 32 14 13 27 15 10 e105 20 26 44 38 24 17 23 14 13 27 15 11 e95 21 28 41 35 23 17 17 14 12 24 15 11 e79 22 84 37 34 22 16 16 14 12 21 15 100 e68 23 56 38 33 21 16 16 13 11 19 15 53 e66 24 39 40 33 20 16 24 16 11 19 14 26 e63 25 37 35 32 20 25 34 23 10 17 14 17 e60 26 76 33 31 20 22 28 27 9.7 17 14 120 e67 27 249 40 30 21 17 19 18 9.4 17 14 107 e82 28 311 92 30 48 17 17 16 9.1 17 13 35 e75 29 177 65 56 27 --- 28 20 8.9 16 13 159 e75 30 116 50 36 22 --- 20 21 13 16 13 149 e78 31 262 --- 33 21 --- 16 --- 9.7 --- 13 51 --- TOTAL 2478 2269 1791 953 549 624 779 568.8 1840 545 1112 2300 MEAN 79.9 75.6 57.8 30.7 19.6 20.1 26.0 18.3 61.3 17.6 35.9 76.7 MAX 311 194 235 69 31 34 175 123 259 33 159 192 MIN 26 33 30 20 16 14 13 8.9 16 13 10 38 AC-FT 4920 4500 3550 1890 1090 1240 1550 1130 3650 1080 2210 4560 CFSM 4.79 4.53 3.46 1.84 1.17 1.21 1.55 1.10 3.67 1.05 2.15 4.59 IN. 5.52 5.05 3.99 2.12 1.22 1.39 1.74 1.27 4.10 1.21 2.48 5.12 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1969 - 1999, BY WATER YEAR (WY) MEAN 83.6 51.7 28.3 21.1 16.5 15.0 27.1 49.2 20.6 15.9 21.6 118 MAX 392 205 108 83.4 43.5 59.9 80.2 179 78.6 104 152 1104 (WY) 1971 1971 1971 1992 1998 1972 1980 1981 1979 1979 1979 1996 MIN 14.6 7.12 4.29 3.66 5.70 4.18 4.92 4.24 3.59 3.22 3.97 3.55 (WY) 1994 1995 1995 1995 1994 1994 1995 1994 1994 1994 1994 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1969 - 1999 ANNUAL TOTAL 31249.8 15808.8 ANNUAL MEAN 85.6 43.3 39.1 HIGHEST ANNUAL MEAN 117 1996 LOWEST ANNUAL MEAN 6.56 1994 HIGHEST DAILY MEAN 10000 Sep 22 311 Oct 28 19500 Sep 10 1996 LOWEST DAILY MEAN 5.5 Mar 19 8.9 May 29 2.8 Jul 23 1994 ANNUAL SEVEN-DAY MINIMUM 5.8 Mar 14 9.9 May 23 2.8 Jul 23 1994 INSTANTANEOUS PEAK FLOW 1580 Sep 6 28200 Sep 22 1998 INSTANTANEOUS PEAK STAGE 11.32 Sep 6 25.93 Sep 22 1998 INSTANTANEOUS LOW FLOW 2.6 Jul 26 1994 ANNUAL RUNOFF (AC-FT) 61980 31360 28330 ANNUAL RUNOFF (CFSM) 5.13 2.59 2.34 ANNUAL RUNOFF (INCHES) 69.61 35.21 31.82 10 PERCENT EXCEEDS 150 98 66 50 PERCENT EXCEEDS 27 26 13 90 PERCENT EXCEEDS 6.5 14 5.5 e Estimated 111 RIO GRANDE DE MANATI BASIN 50034000 RIO BAUTA NEAR OROCOVIS, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 1,000 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 112 RIO GRANDE DE MANATI BASIN 50035000 RIO GRANDE DE MANATI AT CIALES, PR 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 Valés, and 1.2 mi (1.9 km) southeast of Ciales. DRAINAGE AREA.--128 mi2 (332 km2), excludes 6.0 mi2 (15.5 km2), the runoff from which is diverted through El Guineo and 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 Río Grande de Manatí at Highway 145 at Ciales at site 1.6 mi (2.6 km) downstream, drainage area 132 mi2 (342 km2). 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. Gage-height and precipitation satellite telemetry at station. 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e470 808 1530 251 e187 e154 101 96 e1320 124 107 303 2 e392 e704 2810 244 e262 e280 338 87 e1230 209 109 422 3 e369 835 2280 243 e209 188 791 84 e730 177 128 597 4 e338 621 1070 235 e171 137 517 84 e371 133 127 535 5 e314 464 771 225 e166 127 177 122 e309 551 154 508 6 e296 414 580 229 e161 120 132 432 e299 259 124 1890 7 e313 386 503 222 e156 118 115 199 e407 152 107 880 8 299 391 437 214 e152 117 108 1220 e1770 221 102 1070 9 273 404 403 209 e149 127 136 424 e2330 238 100 1230 10 e254 475 371 216 e147 146 117 157 e1420 187 99 772 11 e247 458 378 225 e144 140 108 121 e805 152 99 526 12 e260 1280 352 210 e144 184 100 107 544 151 99 444 13 e245 1620 347 207 e143 197 96 99 363 135 117 1810 14 e246 878 333 247 e142 128 93 93 259 143 123 1040 15 e226 744 315 238 e140 116 91 86 224 165 147 657 16 240 594 309 314 e156 112 89 83 197 160 112 560 17 222 516 298 254 e148 110 86 82 558 173 140 432 18 220 470 290 209 e144 108 84 82 351 146 130 381 19 216 444 293 195 e143 193 83 79 210 128 104 2060 20 218 438 346 190 e139 184 83 76 195 123 113 1240 21 229 429 323 186 e138 149 80 74 183 121 121 735 22 371 407 301 182 e136 170 78 75 159 117 500 491 23 345 438 307 e183 e135 128 79 99 151 114 599 410 24 274 466 309 e182 e133 121 87 76 144 113 357 411 25 309 419 290 e174 e131 154 174 72 138 112 292 354 26 727 393 279 e177 e136 153 313 e72 135 110 428 567 27 e2200 502 266 e186 e127 118 164 e98 134 110 529 515 28 2140 681 259 e360 e128 109 129 e137 136 107 299 463 29 1490 604 401 218 --- 127 255 e124 139 106 633 415 30 714 557 298 183 --- 136 145 e173 143 116 669 423 31 1000 --- 262 e172 --- 109 --- e737 --- 121 335 --- TOTAL 15457 17840 17311 6780 4267 4460 4949 5550 15354 4974 7103 22141 MEAN 499 595 558 219 152 144 165 179 512 160 229 738 MAX 2200 1620 2810 360 262 280 791 1220 2330 551 669 2060 MIN 216 386 259 172 127 108 78 72 134 106 99 303 AC-FT 30660 35390 34340 13450 8460 8850 9820 11010 30450 9870 14090 43920 CFSM 3.90 4.65 4.36 1.71 1.19 1.12 1.29 1.40 4.00 1.25 1.79 5.77 IN. 4.49 5.18 5.03 1.97 1.24 1.30 1.44 1.61 4.46 1.45 2.06 6.43 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1946 - 1999, BY WATER YEAR (WY) MEAN 422 341 258 193 167 135 252 406 159 105 151 318 MAX 2422 1006 1296 679 1393 477 1174 2293 512 438 1212 1295 (WY) 1971 1971 1966 1952 1950 1969 1969 1985 1999 1979 1979 1996 MIN 91.9 34.7 29.7 26.2 41.6 29.7 28.5 29.6 17.8 14.1 27.0 23.9 (WY) 1994 1995 1995 1995 1957 1994 1984 1994 1994 1994 1994 1994 113 RIO GRANDE DE MANATI BASIN 50035000 RIO GRANDE DE MANATI AT CIALES, PR--Continued SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1946 - 1999 ANNUAL TOTAL 106357 126186 ANNUAL MEAN 291 346 243 HIGHEST ANNUAL MEAN 520 1971 LOWEST ANNUAL MEAN 47.3 1994 HIGHEST DAILY MEAN 10100 Sep 22 2810 Dec 2 42700 May 18 1985 LOWEST DAILY MEAN 25 Jan 30 72 May 25 8.5 Jul 28 1994 ANNUAL SEVEN-DAY MINIMUM 26 Jan 28 78 May 20 9.5 Jul 24 1994 INSTANTANEOUS PEAK FLOW 12100 Sep 6 128000 Sep 10 1996 INSTANTANEOUS PEAK STAGE 10.83 Sep 6 25.20 Sep 10 1996 INSTANTANEOUS LOW FLOW 69 May 26 8.5 Jul 27 1994 ANNUAL RUNOFF (AC-FT) 211000 250300 176200 ANNUAL RUNOFF (CFSM) 2.28 2.70 1.90 ANNUAL RUNOFF (INCHES) 30.91 36.67 25.81 10 PERCENT EXCEEDS 552 719 444 50 PERCENT EXCEEDS 137 209 114 90 PERCENT EXCEEDS 43 101 50 e Estimated O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 114 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 Río Cialitos, 0.5 mi (0.8 km) north of Ciales plaza. DRAINAGE AREA.--136 mi2 (352 km2) this excludes the 6 mi2 (15.5 km2) upstream from Lago El Guineo and Lago de Matrullas, flow from which is diverted to Río Jacaguas. PERIOD OF RECORD.--Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 05... 1345 E500 226 7.9 26.5 6.7 7.3 91 <10 2500 620 MAR 11... 1400 144 260 7.8 25.0 9.0 8.9 107 <10 3100 600 MAY 13... 1440 151 244 7.8 28.0 10 7.9 102 <10 600 K170 AUG 24... 0940 296 192 7.7 24.9 100 7.3 89 11 K11000 20000 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 05... 87 24 6.5 10 .5 2.2 77 <1.0 8.3 14 MAR 11... -- -- -- -- -- -- 100 -- -- -- MAY 13... 98 25 8.6 11 .5 2.1 90 <1.0 9.1 13 AUG 24... 74 18 6.9 9.6 .5 1.9 72 -- 8.1 9.9 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 05... .10 25 136 -- 4 -- <.010 1.50 .050 -- MAR 11... -- -- -- -- 9 -- <.010 .770 .050 -- MAY 13... .12 25 148 60.2 10 -- <.010 .780 .030 -- AUG 24... <.10 23 121 96.8 136 .860 .030 .890 .080 .59 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 05... <.20 -- -- .060 <1 <100 20 <1 <1 <10 MAR 11... E.34 -- -- E.080 -- -- -- -- -- -- MAY 13... <.20 -- -- E.070 <1 50 50 <1 <1 18 AUG 24... .67 1.6 6.9 .200 -- -- -- -- -- -- 115 RIO GRANDE DE MANATI BASIN 50035500 RIO GRANDE DE MANATI AT HIGHWAY 149 AT CIALES, RP--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 05... 380 <1 26 <.10 <1 <1 10 <.010 <4 .02 MAR 11... -- -- -- -- -- -- -- -- -- -- MAY 13... 280 <1 35 <.10 <1 <1 <40 <.010 <4 <.02 AUG 24... -- -- -- -- -- -- -- -- -- -- 116 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, 0.7 mi (1.1 km) upstream from mouth, and about 0.4 mi (0.6 km) west of Ciales plaza. DRAINAGE AREA.--17.0 mi2 (44.0 km2). PERIOD OF RECORD.--Water years 1969-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 28... 1245 121 265 8.1 25.5 29 7.2 88 <10 2300 3100 MAR 09... 1005 17 243 8.0 22.0 3.2 9.1 103 <10 K140 300 MAY 13... 1240 19 228 7.8 26.5 10 7.8 98 <10 K130 K180 AUG 24... 1115 32 196 8.0 25.5 51 8.2 101 <10 3600 6800 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) OCT 28... 76 23 4.9 9.3 .5 2.4 84 <1.0 8.6 14 MAR 09... -- -- -- -- -- -- 100 -- -- -- MAY 13... 87 24 6.6 10 .5 1.9 85 <1.0 6.5 12 AUG 24... 73 21 5.0 8.4 .4 2.1 74 -- 7.8 10 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) OCT 28... .14 22 135 44.0 35 2.19 .010 2.20 .030 .40 MAR 09... -- -- -- -- 1 -- <.010 .760 .030 -- MAY 13... <.10 28 140 7.06 11 -- <.010 .770 .030 -- AUG 24... <.10 23 122 10.4 43 1.29 .010 1.30 .050 .33 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) OCT 28... .43 2.6 12 .090 <1 <100 20 <1 1 <10 MAR 09... E.22 -- -- E.030 -- -- -- -- -- -- MAY 13... <.20 -- -- E.070 <1 50 E30 <1 <1 <10 AUG 24... .38 1.7 7.4 .110 -- -- -- -- -- -- 117 RIO GRANDE DE MANATI BASIN 50035950 RIO CIALITOS AT HIGHWAY 649 AT CIALES, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) OCT 28... 750 <1 47 <.10 <1 <1 20 <.010 <4 <.02 MAR 09... -- -- -- -- -- -- -- -- -- -- MAY 13... 130 <1 17 <.10 <1 <1 <40 <.010 <4 <.02 AUG 24... -- -- -- -- -- -- -- -- -- -- 118 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 Manatí. DRAINAGE AREA.--197 mi2 (510 km2), approximately, of which about 38 mi2 (98 km2) is partly or entirely noncontributing, excludes 6.0 mi2 (15.5 km2) 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 1200 1690 e1470 e544 227 168 134 230 1070 214 141 298 2 868 1500 e4510 e499 354 287 327 211 1640 250 135 309 3 738 1340 8320 e494 256 233 726 195 1380 313 148 682 4 662 1300 2900 e448 221 170 1570 189 597 225 181 617 5 613 968 1890 413 211 155 376 186 306 694 195 528 6 566 836 1510 406 202 149 269 606 252 730 168 1750 7 538 752 1290 378 196 145 239 338 320 257 147 3170 8 685 727 1100 356 192 142 224 1310 2020 255 139 1170 9 831 675 986 337 187 146 239 1420 3950 394 135 1930 10 602 857 901 326 184 174 218 292 3550 280 135 1760 11 531 863 872 334 183 152 206 215 1690 235 136 636 12 498 970 820 300 182 207 199 189 824 227 137 613 13 508 1770 790 295 181 234 191 176 515 208 134 2040 14 495 1460 752 330 179 164 183 165 417 213 178 2320 15 501 1340 714 270 188 144 173 155 375 219 191 881 16 471 1090 691 435 190 141 168 148 425 242 159 745 17 441 891 701 326 186 138 163 154 871 216 149 511 18 425 795 648 270 172 134 158 150 943 235 198 438 19 410 732 623 249 170 146 152 140 408 193 141 1990 20 414 702 691 239 167 319 148 135 354 183 135 4570 21 400 680 699 232 165 188 145 130 329 179 158 1490 22 520 643 657 228 161 231 140 130 291 172 501 796 23 756 675 644 229 159 165 136 159 273 167 1030 638 24 547 752 702 233 155 161 140 139 257 161 448 614 25 468 683 657 223 150 158 169 132 243 158 270 581 26 1020 620 634 228 170 230 e416 128 235 153 437 732 27 2140 616 630 240 170 161 e357 127 229 152 952 804 28 7270 839 612 438 154 145 e287 217 229 145 326 717 29 4720 989 786 329 --- 140 e244 192 225 142 290 603 30 2660 795 e685 248 --- 187 e530 177 237 147 1330 626 31 2160 --- e593 229 --- 146 --- 686 --- 156 349 --- TOTAL 34658 28550 39478 10106 5312 5460 8627 8821 24455 7515 9173 34559 MEAN 1118 952 1273 326 190 176 288 285 815 242 296 1152 MAX 7270 1770 8320 544 354 319 1570 1420 3950 730 1330 4570 MIN 400 616 593 223 150 134 134 127 225 142 134 298 AC-FT 68740 56630 78300 20050 10540 10830 17110 17500 48510 14910 18190 68550 CFSM 5.68 4.83 6.46 1.65 .96 .89 1.46 1.44 4.14 1.23 1.50 5.85 IN. 6.54 5.39 7.45 1.91 1.00 1.03 1.63 1.67 4.62 1.42 1.73 6.53 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1970 - 1999, BY WATER YEAR (WY) MEAN 722 536 383 265 207 181 347 649 248 156 215 638 MAX 2958 1803 1498 879 444 521 1037 3178 815 577 1644 3732 (WY) 1971 1971 1971 1997 1988 1972 1993 1985 1999 1979 1979 1998 MIN 154 71.0 55.1 59.1 72.0 56.2 49.9 93.7 63.8 53.0 67.9 67.4 (WY) 1995 1995 1998 1995 1994 1994 1995 1989 1994 1994 1984 1994 119 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR--Continued SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1970 - 1999 ANNUAL TOTAL 279980 216714 ANNUAL MEAN 767 594 378 HIGHEST ANNUAL MEAN 756 1971 LOWEST ANNUAL MEAN 96.5 1994 HIGHEST DAILY MEAN 80400 Sep 22 8320 Dec 3 80400 Sep 22 1998 LOWEST DAILY MEAN 47 Jan 31 127 May 27 31 Jan 24 1995 ANNUAL SEVEN-DAY MINIMUM 49 Jan 28 135 May 21 33 Jul 23 1994 INSTANTANEOUS PEAK FLOW 19800 Oct 28 Not determined Sep 10 1996 INSTANTANEOUS PEAK STAGE 29.72 Oct 28 36.39 Sep 10 1996 INSTANTANEOUS LOW FLOW 28 Jan 23 1995 ANNUAL RUNOFF (AC-FT) 555300 429900 273700 ANNUAL RUNOFF (CFSM) 3.89 3.01 1.92 ANNUAL RUNOFF (INCHES) 52.87 40.92 26.06 10 PERCENT EXCEEDS 1090 1300 662 50 PERCENT EXCEEDS 196 306 167 90 PERCENT EXCEEDS 64 147 82 e Estimated O N D J F M A M J J A S 1998 1999 WATER YEAR 100 10,000 200 300 400 500 700 1,000 2,000 3,000 4,000 5,000 7,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 120 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR. WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 29... 1120 3130 192 7.6 24.5 300 6.7 80 20 22000 39000 FEB 24... 1400 153 315 8.0 26.0 18 10.2 125 <10 560 600 MAY 24... 1205 136 310 7.5 29.0 2.4 7.7 100 <10 4200 6100 AUG 26... 1250 306 243 7.7 29.1 17 6.9 90 <10 K7100 3600 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) OCT 29... 68 19 4.9 8.3 .4 2.4 62 <1.0 9.1 12 FEB 24... -- -- -- -- -- -- 130 -- -- -- MAY 24... 120 36 8.1 12 .5 2.3 120 <1.0 9.3 14 AUG 26... 110 30 7.7 12 .5 2.0 100 -- 8.6 12 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) OCT 29... .10 20 113 951 452 1.88 .022 1.90 .090 1.8 FEB 24... -- -- -- -- 23 -- <.010 .480 .020 .21 MAY 24... .14 21 175 64.0 9 -- <.010 .360 .150 -- AUG 26... <.10 23 155 128 44 .980 .020 1.00 .120 .48 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) OCT 29... 1.9 3.8 17 .610 <1 <100 30 <1 14 51 FEB 24... .23 .71 3.1 .090 -- -- -- -- -- -- MAY 24... E.51 -- -- E.120 <1 50 40 <1 <1 E7 AUG 26... .60 1.6 7.1 .160 -- -- -- -- -- -- 121 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) OCT 29... 14000 5 620 <.10 <1 <1 40 <.010 <4 <.02 FEB 24... -- -- -- -- -- -- -- -- -- -- MAY 24... 330 <1 50 <.10 <1 <1 <40 <.010 5 .05 AUG 26... -- -- -- -- -- -- -- -- -- -- 122 LAGUNA TORTUGUERO BASIN 50038200 LAGUNA TORTUGUERO 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 Manati, and 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. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PH OXYGEN, OXYGEN COLI- ANC SPE- WATER DIS- DEMAND, FORM, STREP- WATER CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI UNFLTRD CON- FIELD TEMPER- OXYGEN, (PER- ICAL 0.45 FECAL, FET DUCT- (STAND- ATURE DIS- CENT (HIGH UM-MF (COLS. FIELD DATE TIME ANCE ARD WATER SOLVED SATUR- 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) OCT 28... 0940 1310 8.0 29.0 6.6 85 10 120 K60 120 MAR 10... 1200 1010 7.8 27.5 6.4 81 29 200 200 120 MAY 14... 1100 1160 7.9 29.5 6.8 89 43 140 270 120 AUG 20... 1315 1170 7.9 31.5 6.2 84 25 85 72 110 RESIDUE NITRO- TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- GEN,AM- AT 105 GEN, GEN, GEN, GEN, GEN, MONIA + NITRO- NITRO- SULFIDE DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC GEN, GEN, TOTAL SUS- TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L PENDED (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) OCT 28... <1.0 5 .319 .011 .330 .610 .99 1.6 1.9 8.5 MAR 10... -- 1 .310 .010 .320 .190 -- E.93 -- -- MAY 14... <1.0 <1 .530 .010 .540 .310 -- E1.4 -- -- AUG 20... -- <1 -- <.010 .250 .270 .93 1.2 1.5 6.4 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- DATE (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS P) AS B) AS CU) AS FE) AS MN) AS ZN) AS CN) (UG/L) (MG/L) (00665) (01022) (01042) (01045) (01055) (01092) (00720) (32730) (38260) OCT 28... .030 70 <10 40 <10 <10 <.010 <4 .18 MAR 10... <.020 -- -- -- -- -- -- -- -- MAY 14... <.020 70 <12 30 <3 <40 <.010 <4 .03 AUG 20... <.020 -- -- -- -- -- -- -- -- Río Río Río Río Río Río Dos Corozal Bocas Cibuco Río Río Río Río Río de los Negros Mavilla Mavilla Indio Cibuco Cibuco Morovis MOROVIS Laguna Tortuguero Unibón 038320 QUALITY-OF-WATER STATION AND NUMBER 038320 213 EXPLANATION WELL AND WELL NUMBER DRAINAGE BASIN BOUNDARY TOWN OR CITY SURFACE-WATER STATION AND NUMBER Figure 15. Río Cibuco basin. 123 MANATÍ VEGA BAJA VEGA ALTA TOA ALTA DORADO Basin area PUERTO RICO TOA BAJA ATLANTIC OCEAN OROCOVIS CIALES COROZAL COMERÍO NARANJITO 0 0 1 1 2 2 3 3 4 4 5 MILES 5 KILOMETERS 0395 0382 038320 70 212 211 1102 1101 1103 213 124 RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR LOCATION.--Lat l8°21'13", long 66°20'07", Hydrologic Unit 21010001, on right bank, 150 ft (46 m) downstream from junction with Río Corozal, and 1.4 mi (2.3 km) northwest of Corozal. DRAINAGE AREA.--15.1 mi2 (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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e27 e204 e400 e33 e46 e15 e12 9.2 e66 e16 18 e12 2 e22 e172 e580 e32 e35 e15 e13 8.7 e43 e75 16 131 3 e25 e54 e450 e31 e28 e14 e32 8.4 e27 e24 15 e29 4 e24 e30 e260 e30 e25 e13 e14 8.3 e30 e22 15 e34 5 e25 e20 e150 e39 e23 e13 e12 9.6 e22 e37 14 e15 6 e20 e15 e94 e31 e22 e13 e11 53 e21 e20 e13 e14 7 e132 e23 e80 e28 e20 e14 e15 e12 e78 e17 12 e18 8 e75 e15 e73 e27 e20 e18 e15 e260 e129 e79 11 e75 9 44 e73 e64 e27 e19 e27 13 e35 e175 e67 11 e27 10 22 e51 e66 e31 e19 e16 e11 e16 e87 e28 11 e19 11 20 e101 e60 e25 e18 e48 e10 e13 e34 e43 10 23 12 16 e571 e56 e23 e20 e25 e10 e11 e21 e27 9.8 e18 13 21 e200 e50 e22 e19 e18 e10 14 e21 e36 9.0 16 14 e17 e107 e45 e23 e22 e16 e9.9 e9.2 e20 e32 8.8 16 15 e14 e82 e43 e33 e25 e16 e8.6 e8.8 e24 e86 9.5 e15 16 16 e71 e40 e22 e19 e15 e8.0 e8.8 e19 e30 9.8 e15 17 19 e46 e37 e20 e17 e16 e8.0 e9.2 e32 e83 e10 15 18 18 e47 e35 e18 e17 e15 e8.0 e9.2 e19 e33 e9.0 21 19 e41 e34 e50 e18 e17 e16 e7.9 e8.8 e23 e24 7.7 e43 20 16 e43 e51 e17 e16 e14 e7.6 e8.8 e20 e21 12 e570 21 16 e32 e39 e17 e15 e13 e7.6 e8.4 e18 e20 e11 e41 22 e16 e58 e62 e18 e15 e19 e8.0 e8.6 e18 20 31 e26 23 e14 e64 e64 e20 e15 e44 e8.4 e8.8 e17 19 e16 21 24 12 e45 e50 e17 e15 e17 e7.9 e8.8 e18 19 e10 e34 25 13 e35 e54 e17 e14 e15 e7.9 e9.0 e17 18 e7.6 e23 26 e106 e32 e48 e20 e14 e13 12 e11 e19 17 11 132 27 e128 e24 e40 e50 e14 e13 41 e24 e20 16 16 e52 28 e453 e26 e45 e27 e14 e12 e11 e44 e17 16 12 e38 29 e433 e52 e58 e19 --- e12 e10 e22 e18 15 e16 e33 30 e210 e200 e38 e16 --- e13 e9.4 e103 e18 e117 e16 e31 31 e131 --- e35 e18 --- e12 --- e74 --- e26 15 --- TOTAL 2146 2527 3217 769 563 540 359.2 842.6 1091 1103 393.2 1557 MEAN 69.2 84.2 104 24.8 20.1 17.4 12.0 27.2 36.4 35.6 12.7 51.9 MAX 453 571 580 50 46 48 41 260 175 117 31 570 MIN 12 15 35 16 14 12 7.6 8.3 17 15 7.6 12 AC-FT 4260 5010 6380 1530 1120 1070 712 1670 2160 2190 780 3090 CFSM 4.58 5.58 6.87 1.64 1.33 1.15 .79 1.80 2.41 2.36 .84 3.44 IN. 5.29 6.23 7.93 1.89 1.39 1.33 .88 2.08 2.69 2.72 .97 3.84 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1969 - 1999, BY WATER YEAR (WY) MEAN 41.1 47.6 36.6 24.9 21.5 20.9 31.6 43.3 15.3 12.6 16.4 34.2 MAX 135 155 169 69.6 51.3 65.1 111 157 44.4 35.6 50.8 191 (WY) 1991 1971 1971 1992 1988 1981 1973 1986 1987 1999 1979 1996 MIN 8.05 5.63 1.94 6.93 7.75 4.36 3.32 3.20 1.63 2.19 3.44 3.88 (WY) 1979 1998 1998 1995 1994 1984 1984 1977 1994 1994 1978 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1969 - 1999 ANNUAL TOTAL 14418.7 15108.0 ANNUAL MEAN 39.5 41.4 28.9 HIGHEST ANNUAL MEAN 56.5 1971 LOWEST ANNUAL MEAN 7.47 1994 HIGHEST DAILY MEAN 1200 Sep 22 580 Dec 2 3070 Sep 10 1996 LOWEST DAILY MEAN 1.6 Mar 28 7.6 Apr 20 .91 Jul 17 1994 ANNUAL SEVEN-DAY MINIMUM 2.3 Mar 22 7.9 Apr 16 1.2 Jun 21 1994 INSTANTANEOUS PEAK FLOW 11700 Oct 27 20400 Nov 9 1995 INSTANTANEOUS PEAK STAGE 19.15 Oct 27 22.35 Nov 9 1995 ANNUAL RUNOFF (AC-FT) 28600 29970 20960 ANNUAL RUNOFF (CFSM) 2.62 2.74 1.92 ANNUAL RUNOFF (INCHES) 35.52 37.22 26.03 10 PERCENT EXCEEDS 81 75 50 50 PERCENT EXCEEDS 11 20 13 90 PERCENT EXCEEDS 3.4 9.8 5.1 e Estimated 125 RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 1,000 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 126 RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR. WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1969-76, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 26... 1245 14 384 8.0 28.0 3.7 6.8 88 <10 K190 K110 FEB 18... 1140 17 360 7.6 21.0 4.9 8.8 98 <10 K50 230 MAY 10... 1200 20 342 7.6 25.5 14 6.8 84 11 3200 6800 AUG 30... 1440 15 330 8.0 30.1 2.4 6.8 92 <10 3100 480 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) OCT 26... 140 35 14 19 .7 4.1 133 <1.0 14 28 FEB 18... -- -- -- -- -- -- 120 -- -- -- MAY 10... 120 31 11 16 .6 4.2 110 <1.0 19 23 AUG 30... 140 33 13 20 .7 3.2 120 -- 12 24 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) OCT 26... .19 31 225 8.55 5 1.77 .031 1.80 .110 .30 FEB 18... -- -- -- -- 10 .979 .021 1.00 .240 .38 MAY 10... .10 26 197 10.7 11 2.39 .110 2.50 .540 -- AUG 30... <.10 33 210 8.70 <1 2.36 .040 2.40 .060 -- NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) OCT 26... .41 2.2 9.8 .260 <1 <100 30 <1 4 <10 FEB 18... .62 1.6 7.2 .200 -- -- -- -- -- -- MAY 10... E.86 -- -- E.290 <1 40 50 <1 <1 <10 AUG 30... <.20 -- -- .230 -- -- -- -- -- -- 127 RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) OCT 26... 210 <1 52 <.10 <1 <1 30 <.010 <4 <.02 FEB 18... -- -- -- -- -- -- -- -- -- -- MAY 10... 240 <1 29 <.10 <1 <1 <40 <.010 <4 .02 AUG 30... -- -- -- -- -- -- -- -- -- -- 128 RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEGA BAJA, PR LOCATION.--Lat 18°26'53", long 66°22'29", Hydrologic Unit 21010002, on left bank, at bridge on Hwy 2, 0.6 mi (1.0 km) downstream from Río Indio, and 0.8 mi (1.3 km) east of Vega Baja. DRAINAGE AREA.--99.1 mi2 (256.7 km2), of which 25.4 mi2 (65.8 km2), does not contribute directly to surface runoff. WATER-DISCHARGE RECORDS PERIOD OF RECORD.--January 1973 to current year. GAGE.--Water-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 ft3/s (793 m3/s). DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 193 560 1550 202 96 51 42 42 231 42 147 260 2 111 671 2370 186 257 54 42 37 243 612 112 135 3 85 426 3340 181 123 54 46 32 101 258 93 429 4 80 266 2470 171 98 48 113 32 103 134 78 222 5 92 211 1410 173 90 47 51 31 152 435 93 182 6 81 176 800 215 81 47 44 98 79 333 88 116 7 133 152 541 170 76 46 40 168 111 145 135 118 8 341 173 457 152 72 46 55 348 275 192 101 351 9 376 147 419 146 69 65 54 434 600 414 51 336 10 233 400 370 146 66 96 44 92 541 270 58 139 11 129 511 387 170 66 57 39 60 335 188 57 125 12 100 849 348 135 65 170 37 49 146 295 55 152 13 93 1930 325 126 72 82 37 43 98 167 41 85 14 182 655 287 119 66 62 37 38 69 265 41 83 15 89 435 260 125 78 56 36 35 72 331 41 76 16 70 328 248 175 86 56 34 33 165 270 54 93 17 66 268 232 118 67 55 32 33 320 308 44 66 18 59 230 215 108 60 56 32 35 271 316 50 60 19 e54 213 203 101 61 53 32 34 138 185 37 177 20 182 198 291 101 59 55 32 34 186 163 36 e835 21 121 216 295 95 57 50 30 34 105 164 85 728 22 118 185 227 94 54 46 30 32 105 134 102 216 23 119 337 359 99 54 69 32 34 94 127 226 173 24 78 373 369 109 53 156 33 34 55 117 161 e150 25 64 255 287 96 52 61 31 35 45 94 64 e140 26 172 198 318 96 52 52 31 36 42 98 e243 e200 27 740 182 273 114 51 47 74 41 41 94 e376 e230 28 1870 199 243 278 51 45 170 126 46 107 e74 e200 29 1900 213 391 145 --- 44 80 120 43 100 e64 e160 30 1540 318 259 103 --- 42 48 127 54 316 e88 e150 31 551 --- 223 90 --- 46 --- 215 --- 614 e221 --- TOTAL 10022 11275 19767 4339 2132 1914 1438 2542 4866 7288 3116 6387 MEAN 323 376 638 140 76.1 61.7 47.9 82.0 162 235 101 213 MAX 1900 1930 3340 278 257 170 170 434 600 614 376 835 MIN 54 147 203 90 51 42 30 31 41 42 36 60 AC-FT 19880 22360 39210 8610 4230 3800 2850 5040 9650 14460 6180 12670 CFSM 3.26 3.79 6.43 1.41 .77 .62 .48 .83 1.64 2.37 1.01 2.15 IN. 3.76 4.23 7.42 1.63 .80 .72 .54 .95 1.83 2.74 1.17 2.40 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1973 - 1999, BY WATER YEAR (WY) MEAN 158 195 184 102 88.4 80.8 144 183 73.8 58.0 78.5 147 MAX 559 523 1316 339 190 339 667 655 239 235 461 690 (WY) 1986 1980 1982 1997 1988 1990 1987 1985 1987 1999 1979 1996 MIN 45.9 28.3 12.9 30.2 27.2 20.5 16.2 24.7 12.5 14.0 21.2 26.7 (WY) 1974 1998 1998 1995 1994 1994 1984 1977 1994 1994 1978 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1973 - 1999 ANNUAL TOTAL 64937 75086 ANNUAL MEAN 178 206 123 HIGHEST ANNUAL MEAN 236 1982 LOWEST ANNUAL MEAN 38.5 1994 HIGHEST DAILY MEAN 3560 Sep 22 3340 Dec 3 14600 Dec 13 1981 LOWEST DAILY MEAN 13 Mar 26 30 Apr 21 7.2 May 3 1995 ANNUAL SEVEN-DAY MINIMUM 16 Jan 28 31 Apr 20 8.1 Apr 28 1995 INSTANTANEOUS PEAK FLOW 4500 Dec 3 34000 Apr 12 1987 INSTANTANEOUS PEAK STAGE 15.99 Dec 3 19.10 Apr 12 1987 INSTANTANEOUS LOW FLOW 28 Apr 21 7.2 May 2 1995 ANNUAL RUNOFF (AC-FT) 128800 148900 89110 ANNUAL RUNOFF (CFSM) 1.80 2.08 1.24 ANNUAL RUNOFF (INCHES) 24.38 28.19 16.86 10 PERCENT EXCEEDS 371 376 230 50 PERCENT EXCEEDS 47 111 58 90 PERCENT EXCEEDS 21 41 22 e Estimated 129 RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEGA BAJA, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 130 RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEGA BAJA, PR. WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1972 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 04... 0915 268 438 7.8 25.5 30 6.5 82 <10 6000 890 MAR 08... 0950 45 436 7.8 24.5 3.2 6.7 80 <10 380 K210 MAY 11... 1000 53 420 7.8 26.0 20 6.3 78 <10 600 710 AUG 30... 1040 87 425 8.0 26.5 10 6.9 86 <10 3200 2200 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 04... 180 57 8.9 13 .4 4.3 170 <1.0 18 22 MAR 08... -- -- -- -- -- -- 170 -- -- -- MAY 11... 170 54 9.0 14 .5 4.1 150 <1.0 20 21 AUG 30... 190 62 8.9 16 .5 3.5 200 -- 16 23 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 04... .10 19 245 177 59 -- <.010 1.60 .040 .26 MAR 08... -- -- -- -- 2 1.59 .014 1.60 .040 -- MAY 11... .12 17 229 32.8 26 1.67 .030 1.70 .090 -- AUG 30... <.10 20 255 59.9 <1 1.38 .020 1.40 .050 .28 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 04... .30 1.9 8.4 .110 1 <100 30 <1 3 <10 MAR 08... <.20 -- -- E.120 -- -- -- -- -- -- MAY 11... E.40 -- -- E.140 <1 60 40 <1 2 <10 AUG 30... .33 1.7 7.7 .130 -- -- -- -- -- -- 131 RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEGA BAJA, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 04... 1800 1 120 <.10 <1 <1 10 <.010 <4 <.02 MAR 08... -- -- -- -- -- -- -- -- -- -- MAY 11... 800 <1 61 <.10 <1 <1 <40 <.010 <4 .03 AUG 30... -- -- -- -- -- -- -- -- -- -- 132 THIS PAGE WAS LEFT BLANK INTENTIONALLY Río Río Caño de Martín Peña Río Río Río Río Río Río Río de Río Río Lajas Río Río Río de de de la la la Plata Plata Plata Lago de la Plata Represa de Comerío Laguna San José Bahía de San Juan Bu ra ca nes bo Arroyata C u e s ta Arriba Cañas G u a d i a n a Hondo Usabón Aibonito Matón Guavate Lago Carite 0450 TUNNEL FLOW DIRECTION QUALITY-OF-WATER STATION AND NUMBER 216 1134 EXPLANATION WELL AND WELL NUMBER LAKE-ELEVATION STATION AND NUMBER DRAINAGE BASIN BOUNDARY TOWN OR CITY SEDIMENT STATION AND NUMBER SURFACE-WATER STATION AND NUMBER Figure 16. Río de la Plata basin. 045010 133 0460 0460 VEGA ALTA TOA ALTA DORADO TOA BAJA CATAÑO SAN JUAN ATLANTIC OCEAN AIBONITO BARRANQUITAS CAYEY COROZAL COMERÍO CIDRA NARANJITO AGUAS BUENAS 0 0 1 1 2 2 3 3 4 4 5 MILES Basin area PUERTO RICO 5 KILOMETERS 0460 0450 045010 044950 044850 0444 0438 0430 0399 039950 039990 0440 217 216 1133 1131, 1132 1126 1127 1129, 1130 1128 134 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 mi2 (21.24 km2). ELEVATION RECORDS PERIOD OF RECORD.--May 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 1,789.62 ft (545.48 m), Sep. 21, 1998; minimum elevation,1,761.22 ft (536.81 m), May 28, 1995. EXTREMES FOR CURRENT YEAR.--Maximum elevation 1,783.66 ft (543.66 m), Dec. 29; minimum elevation, 1,770.43 ft (539.63 m), Sep. 13. 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 1,746 0 1,775 6,194 1,760 2,471 1,780 7,704 1,769 4,561 1,790 11,048 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 A 1781.63 1781.69 1781.70 1781.52 1781.10 1779.78 1777.68 1774.61 1772.87 1773.19 1771.25 2 A A 1781.78 1781.64 1781.48 1781.05 1779.77 1777.59 1774.49 1773.47 1773.11 1771.18 3 A 1781.55 1782.56 1781.63 1781.46 1780.96 1779.78 1777.50 1774.38 1773.37 1773.01 1771.10 4 A 1781.51 1782.06 1781.59 1781.46 1780.99 1779.68 1777.41 1774.30 1773.31 1772.95 1771.00 5 A 1781.56 1782.02 1781.58 1781.45 1780.95 1779.66 1777.31 1774.22 A 1772.88 1770.90 6 1781.51 1781.58 1781.81 1781.54 1781.45 1780.90 1779.52 1777.21 1774.12 A 1772.82 1770.81 7 1781.48 1781.55 1781.74 1781.53 1781.49 1780.86 1779.51 1777.12 1774.01 A 1772.78 1770.72 8 1781.47 1781.53 1781.65 1781.51 1781.44 1780.83 1779.44 1777.10 1774.22 A 1772.74 1770.66 9 1781.48 1781.51 1781.63 1781.54 1781.45 1780.78 1779.41 1777.00 1774.13 A 1772.68 1770.70 10 1781.46 1781.54 1781.60 1781.64 1781.42 1780.71 1779.35 1776.90 1774.08 A 1772.63 1770.62 11 1781.42 1781.60 1781.62 1781.60 1781.38 1780.70 1779.30 1776.82 1773.97 A 1772.57 1770.55 12 1781.44 1781.71 1781.59 1781.55 1781.47 1780.66 1779.22 1776.72 1773.88 A 1772.46 1770.45 13 1781.45 1781.94 1781.55 1781.53 1781.48 1780.59 1779.19 1776.64 1773.78 A 1772.38 1774.26 14 1781.42 1781.74 1781.57 1781.51 1781.44 1780.52 1779.10 1776.52 1773.72 A 1772.27 1775.45 15 1781.43 1781.62 1781.55 1781.63 1781.46 1780.56 1779.04 1776.43 1773.61 A 1772.19 1775.52 16 1781.39 1781.61 1781.53 1781.67 1781.40 1780.49 1778.99 1776.33 1773.54 A 1772.11 1775.55 17 1781.38 1781.60 1781.48 1781.61 1781.35 1780.43 1778.91 1776.22 1773.70 A 1772.01 1775.54 18 1781.33 1781.58 1781.52 1781.56 1781.35 1780.37 1778.86 1776.12 1773.60 A 1771.90 1775.62 19 1781.40 1781.54 1781.50 1781.53 1781.34 1780.30 1778.79 1776.01 1773.64 A 1771.91 1776.39 20 1781.75 1781.54 1781.50 1781.53 1781.27 1780.29 1778.76 1775.92 1773.93 A 1771.84 1776.43 21 1781.71 1781.55 1781.49 1781.55 1781.29 1780.24 1778.67 1775.80 1773.86 1774.02 1771.77 1776.44 22 1783.07 1781.50 1781.49 1781.56 1781.30 1780.17 1778.55 1775.69 1773.79 1773.95 1771.92 1776.35 23 1782.35 1781.50 1781.49 1781.59 1781.24 1780.07 1778.47 1775.60 1773.70 1773.90 1771.87 1776.32 24 1781.92 1781.50 1781.48 1781.53 1781.18 1780.18 1778.38 1775.50 1773.59 1773.84 1771.84 1776.32 25 1781.75 1781.47 1781.48 1781.53 1781.17 1780.23 1778.29 1775.39 1773.51 1773.77 1771.78 1776.29 26 1781.65 1781.46 1781.47 1781.52 1781.11 1780.11 1778.19 1775.29 1773.40 1773.69 1771.70 1776.27 27 1781.94 1781.46 1781.49 1781.50 1781.16 1780.07 1778.10 1775.17 1773.27 1773.61 1771.63 1776.47 28 1781.75 1781.49 1783.54 1781.51 1781.09 1780.02 1777.99 1775.06 1773.17 1773.52 1771.56 1777.65 29 1781.65 1781.49 1782.32 1781.48 --- 1779.91 1777.88 1774.94 1773.07 1773.43 1771.48 1777.92 30 1781.62 1781.48 1781.95 1781.43 --- 1779.92 1777.79 1774.83 1772.96 1773.36 1771.39 1777.95 31 1781.61 --- 1781.80 1781.46 --- 1779.89 --- 1774.73 --- 1773.29 1771.34 --- MAX --- --- 1783.54 1781.70 1781.52 1781.10 1779.78 1777.68 1774.61 --- 1773.19 1777.95 MIN --- --- 1781.47 1781.43 1781.09 1779.89 1777.79 1774.73 1772.96 --- 1771.34 1770.45 A No gage-height record 135 RIO DE LA PLATA BASIN 50043000 RIO DE LA PLATA AT PROYECTO LA PLATA, PR. WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1958 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 03... 1100 117 316 8.1 26.0 19 7.7 97 <10 2200 K82 MAR 08... 1430 34 443 8.2 26.0 2.0 8.7 110 <10 K50 920 MAY 12... 1055 15 417 8.2 27.0 10 10.7 139 11 K1200 K90 SEP 02... 1100 15 476 8.5 29.0 5.3 8.5 115 <10 K180 K150 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 03... 110 28 11 19 .8 1.9 110 <1.0 11 22 MAR 08... -- -- -- -- -- -- 150 -- -- -- MAY 12... 140 35 14 32 1 2.4 140 <1.0 18 35 SEP 02... 150 36 15 40 1 3.3 150 -- 21 46 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 03... <.10 22 181 57.4 19 1.30 .098 1.40 .020 .21 MAR 08... -- -- -- -- <1 1.87 .029 1.90 .040 -- MAY 12... .15 22 242 10.1 8 2.26 .040 2.30 .050 -- SEP 02... .13 24 276 11.5 8 2.17 .030 2.20 .060 .47 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 03... .23 1.6 7.2 .060 <1 <100 30 <1 <1 <10 MAR 08... E.26 -- -- <.020 -- -- -- -- -- -- MAY 12... E.46 -- -- E.150 <1 30 80 <1 <1 18 SEP 02... .53 2.7 12 .100 -- -- -- -- -- -- 136 RIO DE LA PLATA BASIN 50043000 RIO DE LA PLATA AT PROYECTO LA PLATA, PR.--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 03... 710 <1 23 <.10 <1 <1 <10 <.010 <4 .02 MAR 08... -- -- -- -- -- -- -- -- -- -- MAY 12... 170 <1 18 <.10 <1 <1 <40 <.010 <4 <.02 SEP 02... -- -- -- -- -- -- -- -- -- -- 137 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR LOCATION.--Lat 18°13'23", long 66°13'30", Hydrologic Unit 21010005, on right bank 50 ft (15 m) upstream from bridge off Highway 167 in the Town of Comerío, 0.4 mi (0.6 km) southwest of Comerío High School, and 0.2 mi (0.3 km) northeast of Plaza de Comerío. DRAINAGE AREA.--109 mi2 (282 km2). 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 except those for estimated daily discharges, which are poor. 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 218 243 1060 236 95 55 41 36 52 24 32 44 2 164 e200 2020 187 120 126 40 32 46 534 31 49 3 152 173 1450 182 93 93 125 30 65 207 35 60 4 138 144 1580 156 88 54 148 31 36 59 36 129 5 123 127 615 145 88 48 57 31 54 122 41 63 6 113 121 555 145 83 46 44 38 27 45 41 115 7 113 120 446 128 80 43 40 50 24 28 41 135 8 108 116 271 123 77 40 39 107 209 34 48 161 9 100 110 220 119 76 44 39 113 385 454 43 154 10 95 142 199 128 77 47 43 87 196 228 35 122 11 90 147 198 158 79 42 54 67 101 86 43 88 12 97 648 178 134 78 44 41 51 78 73 40 79 13 91 1220 159 121 85 50 39 44 50 63 29 1370 14 88 557 144 114 77 40 37 38 32 244 27 1600 15 90 307 135 181 75 37 36 35 27 416 28 332 16 79 199 131 199 81 36 35 32 28 171 26 134 17 77 167 138 173 73 39 35 30 146 84 27 92 18 74 149 124 137 67 38 34 30 155 129 29 79 19 74 132 119 124 64 37 32 32 41 69 26 1030 20 173 149 148 120 63 41 35 35 30 54 32 660 21 223 130 140 115 61 39 35 33 55 48 36 165 22 2150 113 124 111 58 37 34 31 35 39 224 e92 23 1280 111 118 108 58 40 33 30 25 36 458 e74 24 475 211 116 110 55 49 35 28 21 34 115 e91 25 255 130 112 108 56 58 90 30 18 33 66 e120 26 e245 105 109 111 54 50 87 28 17 33 55 e90 27 e1170 95 107 106 50 44 54 32 17 33 51 e300 28 995 98 107 204 48 41 67 42 19 31 42 e1400 29 548 114 2510 120 --- 40 46 27 24 29 42 565 30 320 148 535 97 --- 47 42 50 25 40 47 96 31 523 --- 313 90 --- 45 --- 27 --- 39 45 --- TOTAL 10441 6426 14181 4290 2059 1490 1517 1307 2038 3519 1871 9489 MEAN 337 214 457 138 73.5 48.1 50.6 42.2 67.9 114 60.4 316 MAX 2150 1220 2510 236 120 126 148 113 385 534 458 1600 MIN 74 95 107 90 48 36 32 27 17 24 26 44 MED 138 143 159 124 76 44 40 32 36 54 41 121 AC-FT 20710 12750 28130 8510 4080 2960 3010 2590 4040 6980 3710 18820 CFSM 3.10 1.97 4.22 1.28 .68 .44 .47 .39 .63 1.05 .56 2.92 IN. 3.58 2.20 4.86 1.47 .71 .51 .52 .45 .70 1.21 .64 3.25 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1989 - 1999, BY WATER YEAR (WY) MEAN 231 114 93.1 136 97.7 44.1 53.4 85.9 72.5 91.7 92.8 461 MAX 866 214 457 732 268 75.7 162 263 213 291 277 1433 (WY) 1991 1999 1999 1992 1998 1989 1993 1992 1996 1993 1998 1996 MIN 40.6 19.0 17.1 21.3 24.4 20.6 22.3 19.7 13.2 10.4 12.7 26.2 (WY) 1992 1995 1995 1995 1990 1993 1991 1994 1994 1994 1994 1997 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1989 - 1999 ANNUAL TOTAL 96625 58628 ANNUAL MEAN 265 161 130 HIGHEST ANNUAL MEAN 239 1996 LOWEST ANNUAL MEAN 35.3 1994 HIGHEST DAILY MEAN 26900 Sep 22 2510 Dec 29 32400 Sep 10 1996 LOWEST DAILY MEAN 11 Aug 4 17 Jun 26 5.8 Jun 25 1994 ANNUAL SEVEN-DAY MINIMUM 12 Jul 31 20 Jun 23 7.3 Jul 31 1994 INSTANTANEOUS PEAK FLOW 6510 Dec 29 127000 Jan 5 1992 INSTANTANEOUS PEAK STAGE 9.50 Dec 29 29.22 Jan 5 1992 ANNUAL RUNOFF (AC-FT) 191700 116300 93920 ANNUAL RUNOFF (CFSM) 2.44 1.48 1.19 ANNUAL RUNOFF (INCHES) 33.13 20.10 16.23 10 PERCENT EXCEEDS 401 261 179 50 PERCENT EXCEEDS 60 79 39 90 PERCENT EXCEEDS 18 31 15 e Estimated 138 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 139 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR--Continued WATER-QUALITY RECORDS PERIOD OF 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. 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 1999.-- SEDIMENT CONCENTRATION: Maximun daily mean, 1,360 mg/L December 29, 1998; Minimun daily mean, 3 mg/L several days. SEDIMENT LOADS: Maximun daily mean, 12,000 tons (10,900 tonnes) December 29, 1998; Minimun daily mean, 0.33 tons (0.30 tonns) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 218 100 61 243 95 67 1060 459 2440 2 164 35 16 e200 e200 e28 2020 898 5200 3 152 12 5.1 173 20 9.8 1450 519 2460 4 138 5 2.0 144 9 3.4 1580 749 3860 5 123 5 1.5 127 7 2.5 615 148 256 6 113 4 1.3 121 7 2.4 555 139 260 7 113 4 1.3 120 8 2.6 446 232 293 8 108 6 1.8 116 9 2.8 271 141 104 9 100 9 2.4 110 10 3.0 220 115 69 10 95 12 3.0 142 10 3.8 199 99 53 11 90 12 2.9 147 26 13 198 90 48 12 97 12 3.0 648 261 850 178 82 39 13 91 11 2.8 1220 496 1790 159 76 33 14 88 11 2.7 557 259 423 144 73 29 15 90 11 2.6 307 127 107 135 70 26 16 79 11 2.3 199 70 38 131 67 24 17 77 11 2.2 167 42 19 138 64 24 18 74 10 2.1 149 36 14 124 62 21 19 74 10 2.0 132 32 11 119 59 19 20 173 64 43 149 69 28 148 58 23 21 223 119 77 130 28 9.8 140 58 22 22 2150 833 7660 113 22 6.7 124 57 19 23 1280 689 2870 111 21 6.4 118 57 18 24 475 202 271 211 33 20 116 57 18 25 255 103 72 130 26 9.1 112 57 17 26 e245 e133 e102 105 19 5.5 109 57 17 27 e1170 e564 e4230 95 15 3.9 107 56 16 28 995 645 2080 98 15 4.0 107 57 16 29 548 320 495 114 15 4.6 2510 1360 12000 30 320 178 160 148 15 6.0 535 303 448 31 523 146 287 --- --- --- 313 170 147 TOTAL 10441 --- 18465.0 6426 --- 3494.3 14181 --- 28019 140 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 236 115 74 95 41 10 55 5 .77 2 187 96 49 120 36 12 126 56 21 3 182 80 39 93 32 8.0 93 110 29 4 156 67 28 88 28 6.7 54 29 4.4 5 145 56 22 88 25 5.8 48 6 .72 6 145 47 18 83 22 4.9 46 4 .45 7 128 39 14 80 19 4.1 43 3 .39 8 123 33 11 77 17 3.5 40 3 .33 9 119 25 8.1 76 15 3.0 44 3 .41 10 128 17 6.0 77 13 2.7 47 4 .50 11 158 12 5.2 79 11 2.4 42 5 .55 12 134 8 3.1 78 10 2.1 44 6 .69 13 121 6 2.0 85 9 2.0 50 7 .91 14 114 6 1.9 77 8 1.6 40 8 .82 15 181 66 42 75 7 1.4 37 9 .88 16 199 42 24 81 6 1.3 36 9 .88 17 173 42 19 73 5 1.0 39 9 .94 18 137 65 24 67 5 .84 38 8 .79 19 124 89 30 64 4 .71 37 6 .63 20 120 84 27 63 4 .68 41 5 .60 21 115 78 24 61 4 .65 39 5 .50 22 111 72 22 58 4 .62 37 4 .42 23 108 67 20 58 3 .54 40 5 .55 24 110 62 19 55 3 .46 49 7 .95 25 108 58 17 56 3 .48 58 16 2.4 26 111 54 16 54 3 .49 50 35 4.7 27 106 50 14 50 4 .48 44 40 4.8 28 204 99 58 48 4 .48 41 39 4.3 29 120 62 20 --- --- --- 40 39 4.2 30 97 47 12 --- --- --- 47 42 5.4 31 90 44 11 --- --- --- 45 47 5.6 TOTAL 4290 --- 680.3 2059 --- 78.93 1490 --- 99.48 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) APRIL MAY JUNE 1 41 43 4.7 36 25 2.4 52 53 12 2 40 37 4.1 32 14 1.2 46 89 11 3 125 67 43 30 9 .74 65 83 15 4 148 85 41 31 11 .91 36 70 7.0 5 57 24 3.8 31 14 1.2 54 38 6.7 6 44 17 2.0 38 11 1.1 27 13 .96 7 40 13 1.4 50 8 1.1 24 10 .61 8 39 10 1.0 107 49 21 209 96 156 9 39 7 .77 113 57 19 385 213 333 10 43 6 .73 87 26 6.6 196 118 73 11 54 6 .82 67 11 1.9 101 71 20 12 41 5 .58 51 8 1.2 78 54 12 13 39 6 .65 44 8 .94 50 38 5.2 14 37 8 .77 38 8 .81 32 28 2.4 15 36 8 .73 35 8 .72 27 22 1.6 16 35 7 .67 32 7 .64 28 18 1.3 17 35 7 .63 30 7 .57 146 71 87 18 34 6 .58 30 8 .65 155 92 55 19 32 6 .53 32 10 .84 41 22 2.5 20 35 6 .60 35 14 1.3 30 13 1.1 21 35 7 .66 33 20 1.8 55 29 4.5 22 34 9 .79 31 19 1.6 35 18 1.7 23 33 11 .95 30 17 1.4 25 11 .75 24 35 11 1.0 28 15 1.2 21 11 .62 25 90 46 30 30 14 1.1 18 11 .54 26 87 20 6.3 28 12 .95 17 11 .50 27 54 19 3.7 32 15 1.6 17 11 .51 28 67 52 9.4 42 28 3.3 19 11 .55 29 46 46 5.8 27 14 1.2 24 11 .70 30 42 40 4.6 50 29 4.2 25 11 .75 31 --- --- --- 27 25 1.8 --- --- --- TOTAL 1517 --- 172.26 1307 --- 84.97 2038 --- 814.49 141 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 24 11 .70 32 14 1.2 44 30 3.6 2 534 245 793 31 14 1.2 49 30 3.9 3 207 124 91 35 14 1.3 60 30 4.9 4 59 30 4.9 36 14 1.3 129 70 58 5 122 100 112 41 14 1.5 63 30 5.2 6 45 21 2.8 41 13 1.5 115 54 64 7 28 11 .81 41 13 1.5 135 78 39 8 34 15 1.6 48 13 1.7 161 78 109 9 454 480 1660 43 13 1.5 154 100 57 10 228 152 123 35 12 1.1 122 74 31 11 86 46 11 43 11 1.3 88 41 11 12 73 46 9.1 40 12 1.3 79 41 9.1 13 63 32 5.5 29 14 1.1 1370 681 4770 14 244 302 434 27 17 1.3 1600 774 3900 15 416 211 270 28 21 1.6 332 181 181 16 171 95 49 26 26 1.8 134 77 28 17 84 41 9.3 27 28 2.0 92 55 14 18 129 60 22 29 29 2.2 79 39 8.4 19 69 33 6.3 26 29 2.1 1030 519 3290 20 54 22 3.2 32 29 2.5 660 156 516 21 48 15 1.9 36 30 2.9 165 22 9.7 22 39 13 1.4 224 115 402 e92 e55 e14 23 36 14 1.4 458 236 496 e74 e34 e8.4 24 34 14 1.3 115 30 9.1 e91 e55 e14 25 33 15 1.3 66 34 6.0 e120 e70 e55 26 33 15 1.3 55 32 4.8 e90 e55 e14 27 33 15 1.3 51 30 4.0 e300 e180 e180 28 31 15 1.2 42 29 3.3 e1400 e681 e4760 29 29 15 1.1 42 29 3.3 565 280 552 30 40 14 1.6 47 29 3.7 96 49 14 31 39 14 1.5 45 29 3.6 --- --- --- TOTAL 3519 --- 3624.51 1871 --- 969.7 9489 --- 18724.2 YEAR 58628 75227.14 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) OCT 28... 0900 1090 468 1380 99 NOV 14... 0705 618 291 486 96 MAR 03... 1745 67 98 18 96 MAY 26... 1340 28 257 19 97 JUL 02... 1520 1040 883 2480 95 142 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. SED. CHARGE, MENT, SUSP. SUSP. SUSP. INST. SEDI- DIS- FALL FALL FALL CUBIC MENT, CHARGE, DIAM. DIAM. DIAM. FEET SUS- SUS- % FINER % FINER % FINER DATE TIME PER PENDED PENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) OCT 22... 1430 3970 1580 17000 56 66 80 JUL 09... 1740 1720 2540 11800 42 50 60 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) OCT 22... 90 97 99 100 100 100 100 JUL 09... 68 77 82 93 98 100 100 143 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 Comerío plaza. DRAINAGE AREA.--139 mi2 (360 km2), excludes 8.2 mi2 (21.1 km2) upstream from Carite Reservoir, the flow of which is diverted to Río Guamaní. PERIOD OF RECORD.--Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 17... 1415 229 350 8.1 27.0 6.9 7.5 96 <10 5500 470 MAR 04... 1215 83 333 8.3 25.5 17 8.7 108 <10 K820 K40 MAY 12... 1605 54 385 8.1 26.5 10 8.0 103 <10 2700 750 SEP 01... 1130 44 399 8.5 29.7 6.5 8.3 113 <10 310 K50 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 17... 130 31 14 30 1 3.1 120 <1.0 13 32 MAR 04... -- -- -- -- -- -- 130 -- -- -- MAY 12... 160 35 17 22 .8 2.0 140 <1.0 15 26 SEP 01... 140 33 15 26 1 3.2 140 -- 15 29 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 17... <.10 25 219 136 9 -- <.010 1.50 .030 .22 MAR 04... -- -- -- -- 7 1.38 .016 1.40 .060 .20 MAY 12... .14 32 231 33.6 6 -- <.010 .630 .030 -- SEP 01... .12 28 233 27.8 13 .990 .010 1.00 .040 .35 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 17... .25 1.8 7.7 .110 <1 <100 50 <1 1 <10 MAR 04... .26 1.7 7.3 .100 -- -- -- -- -- -- MAY 12... <.20 -- -- E.070 <1 20 40 <1 <1 <10 SEP 01... .39 1.4 6.2 .090 -- -- -- -- -- -- 144 RIO DE LA PLATA BASIN 50044000 RIO DE LA PLATA NEAR COMERIO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 17... 390 <1 10 <.10 <1 <1 <10 <.010 <4 .02 MAR 04... -- -- -- -- -- -- -- -- -- -- MAY 12... 110 <1 18 <.10 <1 <1 <40 <.010 <4 <.02 SEP 01... -- -- -- -- -- -- -- -- -- -- 145 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 mi2 (10.3 km2). PERIOD OF RECORD.--Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 09... 0930 20 366 7.9 25.5 .67 7.6 92 <10 K6400 750 FEB 25... 1505 10 361 8.3 25.5 1.8 7.8 95 <10 K9000 K160 MAY 11... 1320 5.3 386 8.0 26.0 10 6.2 78 <10 560 470 AUG 31... 1400 15 345 8.3 29.5 15 7.0 92 <10 3600 3200 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 09... 140 33 15 16 .6 2.8 120 <1.0 22 24 FEB 25... -- -- -- -- -- -- 130 -- -- -- MAY 11... 150 34 15 18 .6 2.5 130 <1.0 21 25 AUG 31... 140 32 15 17 .6 2.5 120 -- 17 22 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 09... .15 24 209 11.2 <1 -- <.010 1.70 .060 .33 FEB 25... -- -- -- -- 5 1.68 .017 1.70 .050 .28 MAY 11... .12 25 219 3.12 30 1.88 .020 1.90 .030 -- AUG 31... .10 27 204 8.26 31 1.69 .010 1.70 .040 .36 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 09... .39 2.1 9.3 .100 1 <100 30 <1 <1 <10 FEB 25... .33 2.0 9.0 .290 -- -- -- -- -- -- MAY 11... <.20 -- -- E.210 1 50 40 <1 <1 <10 AUG 31... .40 2.1 9.3 .230 -- -- -- -- -- -- 146 RIO DE LA PLATA BASIN 50044850 RIO GUADIANA NEAR NARANJITO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 09... 80 <1 44 <.10 <1 <1 <10 <.010 <4 <.02 FEB 25... -- -- -- -- -- -- -- -- -- -- MAY 11... 150 <1 47 <.10 <1 <1 <40 <.010 <4 <.02 AUG 31... -- -- -- -- -- -- -- -- -- -- 147 RIO DE LA PLATA BASIN 50045000 LAGO LA PLATA AT DAMSITE NEAR TOA ALTA, PR LOCATION.--Lat 18°20'40", long 66°14'10", Hydrologic Unit 21010005, 2.9 mi (4.7 km) at northeast of Plaza de Naranjito, 2.7 mi (4.3 km) West of Road 167, km 15.3, Buena Vista, Bayamón, 5.2 mi (8.4 km) east of Plaza de Corozal. DRAINAGE AREA.--181 mi2 (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. New capacity table based on U.S. Geological Survey Water-Resources Investigations Report 00-40-45, October 1998. 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, 168.11 ft (51.24 m), Nov. 27; minimum elevation, 156.67 ft (47.75 m), May 29. Capacity Table (based on data from U.S. Geological Survey Water-Resources Investigations Report 00-4045,Puerto Rico-1998) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 82 0 144 12,915 105 1,873 164 24,021 125 5,943 171 28,748 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 164.80 164.76 165.51 165.93 165.63 165.93 163.47 161.04 A 162.34 163.03 163.29 2 164.12 A 165.64 165.60 165.73 166.11 163.34 160.80 A 164.64 162.97 163.25 3 164.51 165.90 165.56 165.74 165.91 166.23 163.85 160.56 A 163.86 162.88 163.22 4 164.79 166.02 165.48 165.71 165.59 166.19 164.37 160.31 A 163.86 162.75 163.83 5 165.00 165.75 165.47 165.81 165.49 166.13 164.33 160.11 A 163.99 162.65 163.87 6 164.14 165.94 165.47 165.72 165.56 166.03 164.22 160.17 A 164.00 162.54 164.10 7 164.85 165.76 165.43 166.03 165.63 165.95 164.11 160.07 A 163.87 162.42 164.37 8 164.14 165.99 165.79 165.59 165.66 165.86 163.99 160.53 160.26 163.53 162.30 163.94 9 164.29 165.76 165.56 165.88 165.69 166.06 163.88 160.79 162.21 163.87 162.18 164.24 10 164.39 166.03 165.82 165.43 165.73 166.04 163.88 160.79 163.47 164.43 162.02 164.42 11 164.44 165.98 165.95 165.79 165.77 165.98 163.90 160.71 163.77 163.88 161.90 164.33 12 164.52 165.85 165.82 165.74 165.91 165.91 163.78 160.63 163.96 164.07 161.77 164.42 13 164.58 165.75 165.75 165.57 166.04 165.83 163.64 160.45 164.00 164.25 161.59 163.95 14 164.61 165.80 165.45 165.81 166.08 165.69 163.49 160.25 163.98 164.10 161.40 164.02 15 164.65 165.78 165.96 165.55 166.13 165.55 163.32 160.02 163.90 163.90 161.28 163.95 16 164.65 165.83 165.73 165.94 166.20 165.39 163.15 159.78 164.09 164.32 161.14 164.06 17 164.63 166.02 165.44 165.50 166.21 165.24 162.97 A 164.69 163.93 160.96 164.15 18 164.59 165.98 165.85 165.80 166.23 165.10 162.92 159.29 164.42 164.42 160.76 164.16 19 164.70 165.88 165.48 165.94 166.23 164.94 162.75 159.06 163.90 163.82 160.57 164.67 20 164.92 165.77 165.72 165.58 166.20 164.78 162.57 158.81 163.95 163.84 160.45 163.89 21 165.54 165.81 165.89 165.78 166.16 164.62 162.38 158.56 163.99 163.84 160.34 164.07 22 164.84 166.03 165.63 165.96 166.14 164.46 162.20 158.34 163.93 163.78 160.76 164.24 23 165.57 165.95 165.74 165.46 166.10 164.49 162.00 158.08 163.80 163.82 163.53 164.29 24 165.29 165.80 165.66 165.68 166.06 164.38 161.82 157.82 163.64 163.75 163.86 164.42 25 165.13 165.99 166.06 165.88 166.02 164.30 161.69 157.56 163.45 163.64 163.84 164.42 26 164.78 165.89 165.68 165.55 165.97 164.20 161.83 157.28 163.25 163.52 163.73 163.93 27 165.81 165.82 165.71 165.47 165.91 164.07 161.68 A 163.07 163.38 163.60 163.85 28 164.81 165.91 166.11 165.67 165.85 163.94 161.62 A 162.89 163.24 163.44 164.01 29 164.68 165.84 165.47 165.99 --- 163.80 161.45 A 162.72 163.19 163.37 163.86 30 164.73 165.71 165.47 165.44 --- 163.72 161.26 156.99 162.54 163.10 163.24 164.27 31 164.70 --- 165.48 165.54 --- 163.62 --- A --- 163.01 163.39 --- MAX 165.81 --- 166.11 166.03 166.23 166.23 164.37 --- --- 164.64 163.86 164.67 MIN 164.12 --- 165.43 165.43 165.49 163.62 161.26 --- --- 162.34 160.34 163.22 A No gage-height record 148 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM 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, Bayamón, 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 mi2 (448 km2). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--July 1989 to current year. GAGE.--Water-stage recorder. Elevation of gage 164 ft (30 m), from topographic map. 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. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e46 e241 3340 63 169 .70 .17 .07 .80 .16 1.3 1.5 2 e87 e95 5470 393 149 .70 .10 .04 .32 106 1.4 1.5 3 e40 e31 3760 129 .79 .67 .34 .04 .12 657 1.5 1.7 4 e9.9 e22 3660 242 141 .67 .25 .06 .08 39 1.3 2.6 5 e11 e30 e1720 111 101 .70 .22 .06 .06 1.9 1.2 1.8 6 e86 e9.6 e1230 244 .58 .80 .72 .32 .06 1.7 1.3 1.4 7 e11 e15 e1020 1.1 .57 .82 1.1 .29 .04 1.4 1.2 156 8 e78 e5.0 e332 278 .50 .74 .78 4.8 .45 206 1.1 229 9 e38 e51 e476 .55 .52 1.6 2.3 .36 .55 438 1.1 2.2 10 e5.5 e45 290 318 .48 .99 1.7 .09 1.0 167 1.1 2.4 11 e3.1 e71 322 56 .46 .90 .80 .06 .52 537 1.1 242 12 e2.5 e1360 347 118 .40 .96 .73 .08 .46 67 .85 2.1 13 e7.1 e1010 278 185 .43 .87 .75 .06 .29 11 .69 1430 14 e3.3 e207 347 .89 .49 1.2 .88 .44 .45 314 .63 1770 15 e1.9 77 3.8 383 .53 .77 .96 .32 .42 824 .66 429 16 e1.5 37 278 109 .59 .52 .37 .05 .62 164 1.1 89 17 e1.4 80 e262 362 .53 .51 .21 .04 .77 612 .66 2.6 18 e1.1 233 4.1 1.2 1.2 .46 .23 .04 350 2.7 .45 2.3 19 e1.4 168 304 8.5 .43 .49 .15 .05 184 295 .49 1680 20 e2.0 275 159 241 .54 .35 .43 .06 1.0 34 .22 1440 21 e6.3 199 183 .62 .64 .34 .83 .04 .82 1.3 .29 177 22 e1690 67 344 .55 .61 .26 .20 .04 .70 1.7 .23 5.6 23 e592 251 145 270 .67 .55 .24 .05 .72 1.8 1.1 4.4 24 e172 473 250 .82 .71 .35 .22 .03 .75 1.6 1.4 4.6 25 e63 127 4.9 .53 .65 11 .12 .07 .40 1.3 1.4 3.9 26 e309 193 377 184 .65 1.0 .12 .05 .33 1.1 2.0 398 27 e3240 136 143 119 .65 .35 .15 .04 .22 1.2 2.4 214 28 e1890 46 159 363 .60 .48 .10 .07 .20 1.3 1.5 239 29 e1950 266 3120 .73 --- .30 .13 .08 .30 2.0 1.2 791 30 e203 585 256 227 --- .29 .14 .05 .17 2.1 1.0 5.3 31 e140 --- 110 9.3 --- .24 --- .53 --- 1.6 1.7 --- TOTAL 10693.0 6405.6 28694.8 4419.79 574.22 30.58 15.44 8.38 546.62 4495.86 33.57 9329.9 MEAN 345 214 926 143 20.5 .99 .51 .27 18.2 145 1.08 311 MAX 3240 1360 5470 393 169 11 2.3 4.8 350 824 2.4 1770 MIN 1.1 5.0 3.8 .53 .40 .24 .10 .03 .04 .16 .22 1.4 AC-FT 21210 12710 56920 8770 1140 61 31 17 1080 8920 67 18510 CFSM 2.00 1.24 5.36 .83 .12 .01 .00 .00 .11 .84 .01 1.80 IN. 2.30 1.38 6.18 .95 .12 .01 .00 .00 .12 .97 .01 2.01 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1989 - 1999, BY WATER YEAR (WY) MEAN 188 89.1 124 208 55.8 14.4 28.3 98.6 36.4 72.9 39.6 1046 MAX 1107 225 926 1581 241 83.2 231 494 220 384 166 8046 (WY) 1991 1993 1999 1992 1998 1990 1993 1993 1993 1993 1998 1996 MIN .048 .004 .000 .19 .14 .022 .011 .000 .002 .037 .020 .001 (WY) 1992 1995 1995 1990 1995 1995 1995 1994 1994 1994 1989 1991 SUMMARY STATISTICS FOR 1999 WATER YEAR WATER YEARS 1989 - 1999 ANNUAL TOTAL 65247.76 ANNUAL MEAN 179 171 HIGHEST ANNUAL MEAN 714 1996 LOWEST ANNUAL MEAN 8.62 1997 HIGHEST DAILY MEAN 5470 Dec 2 141000 Sep 10 1996 LOWEST DAILY MEAN .03 May 24 .00 Jul 14 1989 ANNUAL SEVEN-DAY MINIMUM .04 May 18 .00 Jul 14 1989 INSTANTANEOUS PEAK FLOW 18500 Dec 29 197000 Sep 10 1996 INSTANTANEOUS PEAK STAGE 16.84 Dec 29 42.26 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 129400 123600 ANNUAL RUNOFF (CFSM) 1.03 .99 ANNUAL RUNOFF (INCHES) 14.05 13.42 10 PERCENT EXCEEDS 348 177 50 PERCENT EXCEEDS 1.4 1.2 90 PERCENT EXCEEDS .15 .00 e Estimated 149 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 0.01 10,000 0.1 1 10 100 1,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 150 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA 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, <1 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) several years. EXTREMES FOR CURRENT YEAR 1999.-- SEDIMENT CONCENTRATION: Maximum daily mean, 1,430 tons (1,300 tonnes) December 2, 1998; Minimum daily mean, ton <0.01 (<0.01 tonnes) several days. SEDIMENT LOADS: Maximum daily mean, 122 mg/L November 19, 1998; Minimum daily mean, 1 mg/L several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 e46 e16 e2.0 e241 e16 e10 3340 99 894 2 e87 e15 e3.6 e95 e16 e4.1 5470 97 1430 3 e40 e15 e1.6 e31 e16 e1.3 3760 94 948 4 e9.9 e14 e.38 e22 e16 e.95 3660 91 903 5 e11 e13 e.39 e30 e17 e1.4 e1720 e89 e411 6 e86 e13 e3.0 e9.6 e17 e.43 e1230 e87 e287 7 e11 e12 e.36 e15 e17 e.70 e1020 e84 e233 8 e78 e11 e2.4 e5.0 e17 e.23 e332 e82 e77 9 e38 e11 e1.1 e51 e18 e2.5 e476 e85 e120 10 e5.5 e11 e.17 e45 e18 e2.1 290 89 74 11 e3.1 e11 e.10 e71 e18 e3.5 322 84 84 12 e2.5 e12 e.08 e1360 e18 e69 347 85 90 13 e7.1 e12 e.23 e1010 e19 e49 278 84 71 14 e3.3 e12 e.11 e207 e19 e10 347 74 82 15 e1.9 e12 e.06 77 17 3.5 3.8 73 .75 16 e1.5 e12 e.05 37 14 1.4 278 76 65 17 e1.4 e13 e.05 80 16 4.2 e262 e71 e60 18 e1.1 e13 e.04 233 81 80 4.1 73 .80 19 e1.4 e13 e.05 168 122 63 304 62 63 20 e2.0 e13 e.07 275 118 99 159 68 33 21 e6.3 e13 e.23 199 114 66 183 68 36 22 e1690 e13 e62 67 112 23 344 64 70 23 e592 e14 e21 251 115 88 145 61 32 24 e172 e14 e6.4 473 117 164 250 62 48 25 e63 e14 e2.4 127 109 40 4.9 40 .54 26 e309 e14 e12 193 113 64 377 56 66 27 e3240 e14 e128 136 86 29 143 49 27 28 e1890 e15 e74 46 80 9.8 159 52 26 29 e1950 e15 e79 266 95 83 3120 47 469 30 e203 e15 e8.3 585 109 171 256 30 21 31 e140 e15 e5.8 --- --- --- 110 56 16 TOTAL 10693.0 --- 414.97 6405.6 --- 1144.11 28694.8 --- 6738.09 151 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 63 54 9.3 169 15 17 .70 4 .01 2 393 61 71 149 18 8.2 .70 4 .01 3 129 56 25 .79 14 .03 .67 4 .01 4 242 58 40 141 14 14 .67 3 .01 5 111 44 15 101 17 5.9 .70 3 .01 6 244 46 30 .58 12 .02 .80 3 .01 7 1.1 41 .12 .57 10 .01 .82 3 .01 8 278 40 31 .50 10 .01 .74 2 <.01 9 .55 37 .05 .52 10 .01 1.6 2 .01 10 318 35 31 .48 10 .01 .99 2 .01 11 56 34 5.1 .46 10 .01 .90 2 <.01 12 118 32 11 .40 10 .01 .96 2 <.01 13 185 30 16 .43 10 .01 .87 2 <.01 14 .89 26 .06 .49 10 .01 1.2 2 <.01 15 383 23 24 .53 10 .01 .77 2 <.01 16 109 22 6.1 .59 10 .02 .52 2 <.01 17 362 18 17 .53 10 .01 .51 1 <.01 18 1.2 17 .05 1.2 10 .03 .46 1 <.01 19 8.5 18 .80 .43 9 .01 .49 1 <.01 20 241 23 15 .54 9 .01 .35 1 <.01 21 .62 20 .03 .64 8 .01 .34 1 <.01 22 .55 18 .03 .61 7 .01 .26 1 <.01 23 270 18 14 .67 7 .01 .55 1 <.01 24 .82 18 .04 .71 6 .01 .35 1 <.01 25 .53 16 .02 .65 6 .01 11 4 .45 26 184 17 16 .65 5 .01 1.0 14 .04 27 119 16 6.5 .65 5 .01 .35 13 .01 28 363 22 29 .60 5 .01 .48 13 .02 29 .73 21 .04 --- --- --- .30 12 .01 30 227 15 15 --- --- --- .29 12 .01 31 9.3 16 .27 --- --- --- .24 11 .01 TOTAL 4419.79 --- 428.51 574.22 --- 45.40 30.58 --- 0.64 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) APRIL MAY JUNE 1 .17 11 <.01 .07 3 <.01 .80 4 .01 2 .10 10 <.01 .04 3 <.01 .32 4 <.01 3 .34 10 .01 .04 3 <.01 .12 4 <.01 4 .25 9 .01 .06 3 <.01 .08 4 <.01 5 .22 9 <.01 .06 3 <.01 .06 4 <.01 6 .72 9 .02 .32 3 <.01 .06 4 <.01 7 1.1 8 .02 .29 2 <.01 .04 4 <.01 8 .78 8 .02 4.8 2 .03 .45 4 <.01 9 2.3 8 .05 .36 2 <.01 .55 3 <.01 10 1.7 7 .03 .09 2 <.01 1.0 3 .01 11 .80 7 .01 .06 2 <.01 .52 3 <.01 12 .73 7 .01 .08 3 <.01 .46 3 <.01 13 .75 6 .01 .06 3 <.01 .29 3 <.01 14 .88 6 .01 .44 3 <.01 .45 4 <.01 15 .96 6 .01 .32 3 <.01 .42 4 <.01 16 .37 6 .01 .05 3 <.01 .62 4 .01 17 .21 6 <.01 .04 3 <.01 .77 4 .01 18 .23 5 <.01 .04 3 <.01 350 15 14 19 .15 5 <.01 .05 3 <.01 184 9 6.1 20 .43 5 .01 .06 3 <.01 1.0 8 .02 21 .83 5 .01 .04 3 <.01 .82 6 .01 22 .20 4 <.01 .04 3 <.01 .70 5 .01 23 .24 4 <.01 .05 3 <.01 .72 4 .01 24 .22 4 <.01 .03 3 <.01 .75 4 .01 25 .12 4 <.01 .07 <.01 .40 2 <.01 26 .12 4 <.01 .05 3 <.01 .33 2 <.01 27 .15 4 <.01 .04 4 <.01 .22 3 <.01 28 .10 4 <.01 .07 4 <.01 .20 3 <.01 29 .13 3 <.01 .08 4 <.01 .30 3 <.01 30 .14 3 <.01 .05 4 <.01 .17 4 <.01 31 --- --- --- .53 4 <.01 --- --- --- TOTAL 15.44 --- 0.24 8.38 --- 0.03 546.62 --- 20.20 152 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 .16 4 <.01 1.3 2 .01 1.5 1 <.01 2 106 5 2.3 1.4 2 .01 1.5 1 <.01 3 657 10 15 1.5 1 .01 1.7 1 <.01 4 39 10 1.1 1.3 1 <.01 2.6 1 .01 5 1.9 10 .05 1.2 1 <.01 1.8 1 <.01 6 1.7 9 .04 1.3 1 <.01 1.4 1 <.01 7 1.4 9 .04 1.2 1 <.01 156 3 2.5 8 206 15 18 1.1 1 <.01 229 5 2.8 9 438 50 45 1.1 1 <.01 2.2 5 .03 10 167 14 15 1.1 1 <.01 2.4 4 .04 11 537 60 47 1.1 1 <.01 242 6 3.9 12 67 8 4.3 .85 1 <.01 2.1 6 .03 13 11 5 1.5 .69 1 <.01 1430 24 174 14 314 20 27 .63 1 <.01 1770 28 141 15 824 80 77 .66 1 <.01 429 12 15 16 164 13 14 1.1 1 <.01 89 6 1.5 17 612 75 66 .66 1 <.01 2.6 5 .03 18 2.7 4 .08 .45 1 <.01 2.3 4 .03 19 295 20 25 .49 1 <.01 1680 15 163 20 34 16 2.0 .22 1 <.01 1440 19 84 21 1.3 7 .03 .29 1 <.01 177 15 7.2 22 1.7 5 .02 .23 1 <.01 5.6 13 .20 23 1.8 3 .01 1.1 1 <.01 4.4 13 .15 24 1.6 2 .01 1.4 1 <.01 4.6 12 .15 25 1.3 2 .01 1.4 1 <.01 3.9 11 .12 26 1.1 2 <.01 2.0 1 <.01 398 17 22 27 1.2 2 .01 2.4 1 .01 214 14 8.4 28 1.3 2 .01 1.5 1 <.01 239 9 5.8 29 2.0 2 .01 1.2 1 <.01 791 17 41 30 2.1 2 .01 1.0 1 <.01 5.3 11 .16 31 1.6 2 .01 1.7 1 <.01 --- --- --- TOTAL 4495.86 --- 360.54 33.57 --- 0.04 9329.9 --- 673.05 YEAR 65247.76 9825.82 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) DEC 30... 1420 339 43 39 91 31... 0350 273 63 46 91 JAN 13... 0834 4.6 30 .37 69 15... 1830 1080 23 67 82 30... 2005 1390 34 128 90 JUN 19... 0615 794 10 21 73 JUL 03... 0545 970 12 31 74 SEP 26... 1240 834 18 41 94 29... 0440 733 181 358 88 153 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HIGHWAY 2 NEAR TOA ALTA, PR 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 Río 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 mi2 (539 km2), excludes 8.2 mi2 (21.2 km2) upstream from Lago Carite, flow from which is diverted to Río Guamaní. Area at site used prior to September 25, 1984, 200 mi2 (518 km2). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--November 1959 (measurement only), January 1960 to current year. Prior to October 1984, published as Río 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. Prior to October, 1984, at site about 1.0 mi (1.6 km) upstream at mean sea level datum. 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 water extraction for La Virgencita water treatment plant by Puerto Rico Aqueduct and Sewer Authority of about 3.99 ft3/s (0.11 m3/s). Located about 1,000 ft 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 ft3/s (3,400 m3/s), gage height, 37.4 ft (11.40 m);June 16, 1943, 82,000 ft3/s (2,322 m3/s), gage height, 34.4 ft (10.48 m), at site 1.0 mi upstream and different datum. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 471 954 3650 259 67 31 23 19 57 27 46 162 2 182 570 6000 304 292 41 31 18 46 729 38 71 3 425 415 5570 115 53 28 37 18 32 605 37 258 4 96 243 4320 321 42 26 34 19 22 165 43 308 5 108 212 1610 79 214 26 27 19 20 107 116 163 6 377 226 997 332 46 25 24 51 19 86 62 104 7 179 162 821 75 38 26 22 47 40 57 218 84 8 194 156 431 226 35 25 25 174 46 106 112 298 9 467 277 437 81 33 48 30 108 130 302 54 92 10 120 450 472 179 35 64 24 38 222 480 44 56 11 80 446 379 207 34 37 22 27 123 433 151 252 12 72 1680 385 57 37 32 22 23 65 327 103 101 13 104 3880 323 255 39 31 21 21 94 150 51 960 14 95 1160 253 56 36 30 21 18 46 289 43 1790 15 66 566 197 217 37 28 20 20 79 557 46 427 16 62 337 266 291 36 28 21 23 137 427 88 197 17 60 322 128 239 32 27 20 20 147 570 92 65 18 56 250 249 104 39 28 19 20 353 220 48 51 19 60 265 131 49 33 31 21 19 392 226 48 758 20 70 215 268 221 32 30 26 19 144 158 42 2270 21 111 256 318 53 32 31 20 18 66 119 42 323 22 2480 212 249 41 30 28 19 22 196 102 48 88 23 2770 393 209 198 30 35 26 29 119 139 103 51 24 749 385 372 85 27 47 22 20 50 87 80 81 25 263 233 103 44 30 31 20 24 35 67 43 72 26 902 214 298 38 31 31 19 24 31 53 37 425 27 3680 223 160 261 28 30 24 19 28 47 35 304 28 5730 202 294 362 25 26 28 31 28 41 33 175 29 4080 239 4170 92 --- 27 23 39 33 36 70 566 30 1090 636 730 54 --- 32 22 23 37 74 68 179 31 705 --- 416 215 --- 25 --- 50 --- 91 344 --- TOTAL 25904 15779 34206 5110 1443 985 713 1020 2837 6877 2385 10731 MEAN 836 526 1103 165 51.5 31.8 23.8 32.9 94.6 222 76.9 358 MAX 5730 3880 6000 362 292 64 37 174 392 729 344 2270 MIN 56 156 103 38 25 25 19 18 19 27 33 51 AC-FT 51380 31300 67850 10140 2860 1950 1410 2020 5630 13640 4730 21280 CFSM 4.18 2.63 5.52 .83 .26 .16 .12 .16 .47 1.11 .39 1.79 IN. 4.82 2.94 6.37 .95 .27 .18 .13 .19 .53 1.28 .44 2.00 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1960 - 1999, BY WATER YEAR (WY) MEAN 465 417 329 182 131 95.1 174 324 156 145 239 442 MAX 4813 2015 1352 929 409 468 722 1939 847 690 1677 3173 (WY) 1971 1985 1971 1992 1989 1969 1987 1985 1970 1961 1979 1996 MIN 18.8 18.4 14.8 16.9 16.0 8.31 5.07 7.63 11.4 13.2 16.5 19.2 (WY) 1995 1995 1995 1984 1983 1986 1984 1984 1977 1994 1976 1991 154 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HIGHWAY 2 NEAR TOA ALTA, PR SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1960 - 1999 ANNUAL TOTAL 167966 107990 ANNUAL MEAN 460 296 256 HIGHEST ANNUAL MEAN 824 1971 LOWEST ANNUAL MEAN 31.5 1994 HIGHEST DAILY MEAN 47100 Sep 22 6000 Dec 2 68100 Sep 10 1996 LOWEST DAILY MEAN 13 Aug 5 18 May 2 2.7 Apr 17 1984 ANNUAL SEVEN-DAY MINIMUM 18 Jul 31 20 Apr 29 2.9 Apr 15 1984 INSTANTANEOUS PEAK FLOW 19200 Oct 27 Not determined Sep 10 1996 INSTANTANEOUS PEAK STAGE 17.93 Oct 27 27.33 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 333200 214200 185700 ANNUAL RUNOFF (CFSM) 2.30 1.48 1.28 ANNUAL RUNOFF (INCHES) 31.27 20.11 17.43 10 PERCENT EXCEEDS 650 471 473 50 PERCENT EXCEEDS 38 72 80 90 PERCENT EXCEEDS 21 23 18 O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 155 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 Río 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 mi2 (539 km2), exclude 8.2 mi2 (21.2 km2) upstream from Lago Carite, flow from which is diverted to Río Guamaní. PERIOD OF RECORD.--Water years 1958 to current year WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 04... 1145 E360 361 7.6 27.5 39 6.4 81 11 K15000 560 FEB 18... 1445 40 479 7.5 25.5 2.8 7.8 95 17 K740 K82 MAY 10... 1510 35 490 7.5 28.0 20 4.3 56 12 K1300 650 AUG 26... 1005 38 446 7.7 29.4 2.7 5.5 72 <10 360 K30 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 04... 140 42 8.2 15 .6 3.4 130 <1.0 15 22 FEB 18... -- -- -- -- -- -- 180 -- -- -- MAY 10... 150 43 9.7 18 .6 3.7 130 <1.0 19 22 AUG 26... 190 59 11 21 .7 2.8 180 -- 17 30 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 04... .11 17 200 -- 36 -- <.010 1.30 .110 .39 FEB 18... -- -- -- -- 3 .896 .074 .970 .150 .43 MAY 10... .14 14 207 19.5 23 .770 .070 .840 .370 -- AUG 26... .10 21 270 27.4 5 .660 .050 .710 .080 .34 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 04... .50 1.8 8.0 .080 1 <100 40 <1 2 <10 FEB 18... .58 1.5 6.9 .050 -- -- -- -- -- -- MAY 10... E1.0 -- -- E.110 <1 80 50 <1 <1 <10 AUG 26... .42 1.1 5.0 .040 -- -- -- -- -- -- 156 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HWY 2 NR TOA ALTA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 04... 1600 1 130 <.10 <1 <1 <10 <.010 4 <.02 FEB 18... -- -- -- -- -- -- -- -- -- -- MAY 10... 500 <1 220 <.10 1 <1 <40 <.010 <4 .04 AUG 26... -- -- -- -- -- -- -- -- -- -- Basin area PUERTO RICO QUALITY-OF-WATER STATION AND NUMBER 047560 0476 047850 652 047550 EXPLANATION WELL AND WELL NUMBER LAKE-ELEVATION STATION AND NUMBER DRAINAGE BASIN BOUNDARY TOWN OR CITY SEDIMENT STATION AND NUMBER SURFACE-WATER STATION AND NUMBER Figure 17. Río Hondo to Río Puerto Nuevo basins. 157 Río Río Río Río Río Pu e r t o N u e vo Piedras Piedras Río Río Guaynabo Q u e b r a d a Quebrada Margarita San Antón de B a y a m ó n Hondo Canal del Río de Bayamón Minillas Lago de Cidra Lago Las Curias Represa de Río Piedras Laguna San José Laguna Martín Peña Bahía de San Juan TOA ALTA DORADO TOA BAJA CATAÑO SAN JUAN ATLANTIC OCEAN COMERIO CIDRA NARANJITO BAYAMÓN GUAYNABO TRUJILLO ALTO AGUAS BUENAS 0 0 1 1 2 2 3 3 4 4 5 MILES 5 KILOMETERS 047560 0476 047850 047990 048510 047530 049920 049820 0491 219 652 1159 1152 1153 1154 1156 1158 1155 048770 048690 0488 047550 047549 048680 047537 047540 047535 158 RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CATAÑO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°26'13", long 66°09'36", at Río Hondo Channel, 800 ft (245 m) below junction with Río 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 1998 TO SEPTEMBER 1999 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. DATE TIME ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) NOV 17... 1130 5620 7.8 28.5 36 2.6 33 15 34000 2000 MAR 16... 0950 33400 7.2 26.9 8.3 8.4 105 160 K1700 K300 JUN 14... 0945 2040 7.6 28.0 50 3.2 41 25 K7200 4000 SEP 02... 1330 26300 8.4 32.0 8.6 11.7 162 -- 460 450 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 17... 500 56 89 734 14 31 100 <1.0 160 1200 MAR 16... -- -- -- -- -- -- 160 -- -- -- JUN 14... 290 47 42 346 9 16 98 <1.0 120 660 SEP 02... 3000 210 596 4970 40 160 130 -- 970 8600 SOLIDS, RESIDUE NITRO- FLUO- SILICA, SUM OF TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- GEN,AM- RIDE, DIS- CONSTI- AT 105 GEN, GEN, GEN, GEN, GEN, MONIA + DIS- SOLVED TUENTS, DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC SOLVED (MG/L DIS- SUS- TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PENDED (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) (MG/L) AS N) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (00530) (00620) (00615) (00630) (00610) (00605) (00625) NOV 17... .12 8.7 2370 56 .335 .075 .410 .670 .63 1.3 MAR 16... -- -- -- 34 .057 .033 .090 .440 -- E1.2 JUN 14... .13 8.4 1300 64 .480 .050 .530 .460 -- E1.2 SEP 02... .42 5.1 15600 56 .020 .020 .040 .050 1.0 1.1 CHRO- BARIUM, BORON, CADMIUM MIUM, COPPER, IRON, NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL TOTAL GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE ERABLE DATE (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) AS FE) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) (01045) NOV 17... 1.7 7.6 .150 3 <100 350 <1 2 14 1000 MAR 16... -- -- E.240 -- -- -- -- -- -- -- JUN 14... -- -- E.110 1 70 190 <1 2 12 1900 SEP 02... 1.1 5.0 .100 -- -- -- -- -- -- -- 159 RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CATAÑO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 17... 2 190 <.10 <1 <1 10 <.010 <4 .06 MAR 16... -- -- -- -- -- -- -- -- -- JUN 14... 2 170 <.10 <1 <1 <40 <.010 6 .12 SEP 02... -- -- -- -- -- -- -- -- -- 160 RIO DE BAYAMON BASIN 50047535 RIO DE BAYAMON AT ARENAS, PR LOCATION.--Lat 18°10'11", long 66°07'18", Hydrologic Unit 21010005, at left bank, 2.61 mi (4.20 km) southeast of plaza de Cidra, 0.56 mi (0.90 km) southwest from Escuela Segunda Unidad de Bayamón, and 2.70 mi (4.34 km) northeast from Central Cayey. DRAINAGE AREA.--0.45 mi2 (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, except those for estimated daily discharges, which are poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 .27 1.3 13 1.2 .44 1.4 .15 .11 .11 .14 .20 .58 2 .25 .62 23 .98 1.2 .58 .17 .10 .09 8.9 .18 .58 3 .25 .41 17 2.5 .59 .29 .67 .10 .09 .69 .29 2.1 4 .23 .37 6.4 .82 .48 .24 .33 .10 .18 .21 .32 .82 5 .22 .31 2.9 .71 .48 .21 .28 .10 .11 .20 .25 .32 6 .22 .29 6.0 .57 .44 .20 .22 .11 .08 .22 .13 .21 7 .21 .26 2.8 .46 .42 .20 .19 .12 .09 .14 .33 .19 8 .19 .25 1.3 .40 .40 .20 .19 .22 .26 .23 .23 .18 9 .17 .35 1.8 .45 .40 .21 .26 .16 .70 1.1 .13 .16 10 .16 .35 1.2 .70 .41 .22 .19 .14 .24 .45 2.5 .16 11 .16 2.5 2.6 .59 .34 .21 .19 .14 .15 .52 .71 .33 12 .17 7.5 1.4 .46 .37 .21 .17 .14 .16 .56 .21 .15 13 .13 6.8 1.0 .40 .34 .20 .16 .12 .16 1.3 .15 10 14 .14 1.4 .79 .37 .34 .18 .15 .11 .10 5.7 .14 5.9 15 .14 .68 .64 5.4 .34 .18 .14 .10 .09 3.9 .14 .91 16 .13 .47 .54 .68 .34 .18 .12 .09 .09 e1.1 .13 .41 17 .15 .51 .50 .46 .31 .16 .12 .09 4.7 .70 .13 .30 18 .14 .38 .45 .37 .30 .17 .13 .08 .67 .40 .13 1.0 19 .25 2.4 .50 .32 .30 .17 .14 .07 .36 .30 .31 14 20 .56 2.4 .54 .33 .30 .16 .14 .07 .30 .27 .32 2.3 21 .34 1.0 .52 .32 .30 .16 .13 .07 .19 .17 .28 .77 22 7.4 .66 .46 .32 .30 .16 .13 .06 .16 .14 4.5 .47 23 2.5 3.0 .47 .34 .29 .15 .15 .06 .14 .15 1.3 .37 24 .72 3.2 .43 .33 .29 .22 .14 .08 .10 .15 .43 .43 25 .45 .90 .44 1.4 .27 .21 .13 .09 .08 .17 .25 .46 26 .34 .72 .42 1.2 .27 .20 .12 .07 .08 .13 .21 1.2 27 12 .51 .41 .84 .25 .17 .13 .06 .09 .12 .20 .89 28 2.9 .42 35 2.7 .23 .21 .13 .07 .08 .11 .17 2.6 29 1.2 .39 15 .92 --- .22 .12 .07 .08 .68 .18 2.1 30 .85 .92 3.9 .59 --- .17 .11 .11 .07 .33 .15 .73 31 .57 --- 2.0 .48 --- .15 --- .10 --- .23 .15 --- TOTAL 33.41 41.27 143.41 27.61 10.74 7.59 5.40 3.11 9.80 29.41 14.75 50.62 MEAN 1.08 1.38 4.63 .89 .38 .24 .18 .10 .33 .95 .48 1.69 MAX 12 7.5 35 5.4 1.2 1.4 .67 .22 4.7 8.9 4.5 14 MIN .13 .25 .41 .32 .23 .15 .11 .06 .07 .11 .13 .15 AC-FT 66 82 284 55 21 15 11 6.2 19 58 29 100 CFSM 2.39 3.06 10.3 1.98 .85 .54 .40 .22 .73 2.11 1.06 3.75 IN. 2.76 3.41 11.86 2.28 .89 .63 .45 .26 .81 2.43 1.22 4.18 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1992 - 1999, BY WATER YEAR (WY) MEAN .75 .81 1.15 .62 .73 .26 .21 .52 .67 .99 .92 2.83 MAX 1.73 1.38 4.63 .89 2.38 .65 .45 2.02 1.79 2.12 1.87 6.52 (WY) 1998 1999 1999 1999 1998 1998 1993 1993 1996 1993 1996 1998 MIN .30 .32 .048 .41 .16 .097 .095 .10 .10 .092 .46 .20 (WY) 1997 1998 1998 1998 1993 1993 1997 1999 1998 1998 1992 1997 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1992 - 1999 ANNUAL TOTAL 569.59 377.12 ANNUAL MEAN 1.56 1.03 .90 HIGHEST ANNUAL MEAN 1.16 1996 LOWEST ANNUAL MEAN .31 1997 HIGHEST DAILY MEAN 97 Sep 22 35 Dec 28 141 Sep 10 1996 LOWEST DAILY MEAN .02 Jul 26 .06 May 22 .02 Jul 3 1997 ANNUAL SEVEN-DAY MINIMUM .03 Jul 8 .07 May 18 .03 Jun 28 1997 INSTANTANEOUS PEAK FLOW 1050 Dec 28 1150 Sep 21 1998 INSTANTANEOUS PEAK STAGE 7.70 Dec 28 7.89 Sep 21 1998 INSTANTANEOUS LOW FLOW .02 Jul 15 1997 ANNUAL RUNOFF (AC-FT) 1130 748 651 ANNUAL RUNOFF (CFSM) 3.47 2.30 2.00 ANNUAL RUNOFF (INCHES) 47.09 31.18 27.14 10 PERCENT EXCEEDS 2.1 2.2 1.2 50 PERCENT EXCEEDS .18 .29 .18 90 PERCENT EXCEEDS .04 .11 .06 e Estimated 161 RIO DE BAYAMON BASIN 50047535 RIO DE BAYAMON AT ARENAS, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 0.01 100 0.02 0.05 0.1 0.2 0.5 1 2 5 10 20 50 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 162 RIO DE BAYAMON BASIN 50047540 RIO SABANA AT VISTA MONTE, PR 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 mi (1.9 km) southwest from Escuela Segunda Unidad de Bayamón, and 0.4 mi (0.6 km) upstream from Lago de Cidra. DRAINAGE AREA.--0.80 mi2 (2.07 km2). PERIOD OF RECORD.--August 1992 to September 1993, October 1995 to current year. GAGE.--Water-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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 1.5 e4.8 26 3.4 1.6 .72 .45 .29 1.2 .76 .54 .37 2 1.5 e2.3 46 3.0 1.1 .60 .48 .28 .25 11 .53 .33 3 1.4 e1.5 26 3.7 .88 .45 4.8 .27 .19 1.4 .47 1.1 4 1.3 e1.4 10 e2.4 .92 .43 .98 .25 .29 .69 .43 .49 5 1.2 e1.2 4.9 e2.1 .87 .43 .64 .27 .32 .49 .43 .35 6 1.4 e1.1 5.1 e1.7 .76 .45 .57 .46 .27 .42 .40 .32 7 1.2 e1.0 3.6 e1.3 .72 .46 .53 .30 .33 .40 .99 .33 8 1.1 e.94 2.6 e1.2 .71 .46 .60 .57 5.3 .84 .55 .30 9 1.1 e1.3 2.8 e1.3 .70 .48 .56 .35 6.8 3.2 .40 .30 10 1.1 e1.3 2.1 e2.1 .70 .48 1.3 .27 1.4 1.1 3.5 .30 11 1.1 e10 3.4 e1.7 .70 .45 .61 .26 .72 3.8 .86 .40 12 1.2 e28 2.2 e1.3 .68 .43 .51 .25 .58 1.8 .49 .26 13 1.1 e25 1.9 e1.2 .63 .41 .51 .24 .61 2.5 .43 4.5 14 1.1 e5.2 1.7 e1.1 .60 .41 .49 .22 .49 5.9 .40 4.5 15 1.0 e2.6 1.5 e5.3 .67 .44 .47 .20 .45 7.6 .39 .69 16 .98 e1.0 1.4 e2.1 .68 .42 .43 .20 .43 2.2 .38 .52 17 .98 e1.1 1.4 e1.4 .68 .42 .42 .18 16 1.9 .38 .40 18 .94 e.82 1.3 e1.1 .71 .41 .43 .19 2.5 1.1 .37 .73 19 1.7 2.9 2.2 e1.7 .58 .44 .43 .19 1.8 .95 .65 10 20 2.3 1.7 1.9 1.3 .56 .43 .38 .20 1.2 1.2 .68 2.2 21 1.9 1.1 1.6 1.2 .55 .43 .36 .19 .88 .74 .45 .88 22 27 1.0 1.5 1.2 .54 .43 .35 .17 .70 .61 5.4 .66 23 7.3 8.5 1.5 1.3 .56 .42 .36 .18 .63 .57 .91 .53 24 3.0 11 1.3 1.9 .53 .64 .35 .18 .54 .57 .48 .50 25 2.1 2.1 1.9 2.2 .53 .46 .33 .20 .49 .48 .38 .48 26 e1.7 1.4 1.3 1.8 .52 .47 .33 .17 .52 .44 .34 2.5 27 e45 1.0 1.2 1.6 .51 .48 .33 .17 .53 .43 .32 1.7 28 e10 .87 46 4.5 .50 .67 .32 .18 .53 .38 .30 8.8 29 e4.5 1.3 28 1.3 --- .50 .32 .20 .51 1.4 .30 9.4 30 e3.2 1.5 6.2 .98 --- .45 .31 .24 .52 .67 .29 1.5 31 e2.1 --- 4.1 .90 --- .46 --- .25 --- .50 .28 --- TOTAL 133.00 124.93 242.6 59.28 19.69 14.63 18.95 7.57 46.98 56.04 22.72 55.34 MEAN 4.29 4.16 7.83 1.91 .70 .47 .63 .24 1.57 1.81 .73 1.84 MAX 45 28 46 5.3 1.6 .72 4.8 .57 16 11 5.4 10 MIN .94 .82 1.2 .90 .50 .41 .31 .17 .19 .38 .28 .26 AC-FT 264 248 481 118 39 29 38 15 93 111 45 110 CFSM 5.36 5.21 9.78 2.39 .88 .59 .79 .31 1.96 2.26 .92 2.31 IN. 6.18 5.81 11.28 2.76 .92 .68 .88 .35 2.18 2.61 1.06 2.57 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1992 - 1999, BY WATER YEAR (WY) MEAN 2.24 1.74 2.12 .96 1.24 .54 .65 .79 .84 1.55 1.33 5.83 MAX 4.51 4.16 7.83 1.91 3.50 1.01 1.23 2.26 1.57 3.02 2.34 16.7 (WY) 1998 1999 1999 1999 1998 1998 1993 1993 1999 1993 1998 1996 MIN .76 .86 .31 .33 .33 .15 .37 .24 .25 .29 .48 .25 (WY) 1997 1998 1998 1998 1993 1993 1996 1999 1997 1997 1997 1997 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1992 - 1999 ANNUAL TOTAL 1191.27 801.73 ANNUAL MEAN 3.26 2.20 1.72 HIGHEST ANNUAL MEAN 2.37 1998 LOWEST ANNUAL MEAN .63 1997 HIGHEST DAILY MEAN 219 Sep 22 46 Dec 2 401 Sep 10 1996 LOWEST DAILY MEAN .09 Jul 13 .17 May 22 .09 Jul 13 1998 ANNUAL SEVEN-DAY MINIMUM .12 Jul 8 .18 May 22 .12 Jun 6 1993 INSTANTANEOUS PEAK FLOW 709 Dec 28 2380 Sep 10 1996 INSTANTANEOUS PEAK STAGE 6.70 Dec 28 12.02 Sep 10 1996 INSTANTANEOUS LOW FLOW .13 Jun 1 .08 Jul 14 1998 ANNUAL RUNOFF (AC-FT) 2360 1590 1250 ANNUAL RUNOFF (CFSM) 4.08 2.75 2.16 ANNUAL RUNOFF (INCHES) 55.39 37.28 29.29 10 PERCENT EXCEEDS 4.0 4.3 1.8 50 PERCENT EXCEEDS .49 .70 .49 90 PERCENT EXCEEDS .24 .30 .21 e Estimated 163 RIO DE BAYAMON BASIN 50047540 RIO SABANA AT VISTA MONTE, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 0.1 100 0.2 0.5 1 2 5 10 20 50 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 164 RIO DE BAYAMON BASIN 50047550 LAGO CIDRA AT DAMSITE NEAR CIDRA, PR LOCATION.--Lat 18°11'57", long 66°08'29", Hydrologic Unit 21010005, at Lago de Cidra Dam on Río de Bayamón, 1.9 mi (3.0 km) northeast of Plaza de Cidra and 1.8 mi (2.9 km) northwest of Escuela Segunda Unidad de Bayamón. DRAINAGE AREA.--8.26 mi2 (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 hm3) and provides supplemental 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. New capacity table based on U.S. Geological Survey Water-Resources Investigations Report 99-4144,November 1997. 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, 1,324.40 ft (403.68 m), Dec. 28; minimum elevation,1,310.11 ft (399.32 m), June 8. Capacity Table (based on data from U.S. Geological Survey Water-Resources Investigations Report 99-4144,Puerto Rico-1997) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 1,260 0 1,309 2,059 1,276 97 1,315 3,170 1,296 762 1,322 4,670 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 1321.88 1320.20 1323.02 1322.46 1322.03 1320.80 1318.47 1315.82 1311.04 1312.68 1315.52 1314.02 2 1321.69 1320.28 1323.17 1322.43 1321.97 1320.76 1318.39 1315.60 1310.90 1313.26 1315.57 1313.81 3 1321.49 1320.36 1323.05 1322.46 1321.95 1320.67 1318.74 1315.43 1310.75 1313.33 1315.59 1313.72 4 1321.26 1320.41 1322.62 1322.43 1321.96 1320.59 1318.65 1315.28 1310.63 1313.42 1315.57 1313.72 5 1321.04 1320.40 1322.54 1322.39 1321.92 1320.50 1318.53 1315.15 1310.48 1313.52 1315.52 1313.56 6 1320.93 1320.37 1322.59 1322.39 1321.88 1320.40 1318.44 1315.05 1310.33 1313.58 1315.45 1313.30 7 1320.72 1320.35 1322.45 1322.36 1321.85 1320.32 1318.37 1314.88 1310.19 1313.65 1315.45 1313.33 8 1320.49 1320.33 1322.44 1322.35 1321.81 1320.19 1318.38 1314.73 A 1313.75 1315.46 1313.24 9 1320.25 1320.39 1322.48 1322.36 1321.75 1320.12 1318.36 1314.55 1310.58 1313.89 1315.46 A 10 1319.99 1320.42 1322.45 1322.41 1321.91 1320.00 1318.56 1314.42 1310.76 1313.96 1315.36 1313.03 11 1319.72 1320.70 1322.48 1322.40 1321.88 1319.90 1318.52 1314.28 1310.80 A 1315.25 1312.98 12 1319.48 1321.80 1322.45 1322.37 1321.87 1319.86 1318.49 1314.15 1310.89 A 1315.17 1312.86 13 1319.21 1322.34 1322.43 1322.26 1321.82 1319.78 1318.47 1314.05 1310.97 A 1315.11 1313.60 14 1318.98 1322.43 1322.39 1322.27 1321.74 1319.78 1318.42 1313.94 1310.98 A 1315.01 1313.81 15 1318.77 1322.41 1322.38 1322.48 1321.67 1319.77 1318.39 1313.83 1311.01 A 1314.89 1313.67 16 1318.60 1322.39 1322.37 1322.35 1321.58 1319.88 1318.29 1313.68 1311.06 1314.33 1314.80 1313.56 17 1318.43 1322.45 1322.35 1322.28 1321.50 1319.81 1318.08 1313.49 1311.76 1314.68 1314.70 1313.40 18 1318.24 1322.41 1322.36 1322.22 1321.43 1319.81 1317.89 1313.30 1311.90 1314.94 1315.24 1313.37 19 1318.14 1322.49 1322.40 1322.16 1321.35 1319.81 1317.68 1313.11 1312.06 1314.95 1315.20 1314.02 20 1318.09 1322.47 1322.43 1322.09 1321.30 1319.76 1317.50 1312.93 1312.16 1315.09 1315.08 1313.97 21 1317.99 1322.42 1322.39 1321.92 1321.24 1319.75 1317.33 1312.73 1312.26 1315.18 1314.95 1313.88 22 1319.32 1322.41 1322.37 1321.80 1321.19 1319.65 A 1312.53 1312.35 1315.24 1315.55 1313.77 23 1319.35 1322.75 1322.39 1321.86 1321.14 1319.55 A 1312.33 1312.45 1315.31 1315.42 1313.68 24 1319.23 1322.55 1322.40 1321.91 1321.06 1319.46 A 1312.16 1312.53 1315.35 1315.22 1313.57 25 1319.07 1322.44 1322.44 1321.97 1321.00 1319.37 A 1312.02 1312.55 1315.33 A 1313.46 26 1318.95 1322.39 1322.42 1321.96 1320.93 1319.23 1316.55 1311.86 1312.58 1315.36 1314.92 1313.62 27 1319.78 1322.39 1322.41 1321.91 1320.86 1319.12 1316.41 1311.72 1312.59 1315.34 1314.74 1313.62 28 1319.84 1322.36 1324.06 1322.11 1320.80 1318.95 1316.25 1311.57 1312.61 1315.33 1314.57 1314.01 29 1319.89 1322.46 1322.68 1322.06 --- 1318.78 1316.11 1311.41 1312.64 1315.42 1314.41 1314.24 30 1319.96 1322.46 1322.54 1322.01 --- 1318.65 1315.98 1311.23 1312.65 1315.46 1314.31 1314.23 31 1320.07 --- 1322.49 1321.95 --- 1318.56 --- 1311.10 --- 1315.48 1314.15 --- MAX 1321.88 1322.75 1324.06 1322.48 1322.03 1320.80 --- 1315.82 --- --- --- --- MIN 1317.99 1320.20 1322.35 1321.80 1320.80 1318.56 --- 1311.10 --- --- --- --- A No gage-height record 165 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR LOCATION.--Lat 18°12'04", long 66°08'26", Hydrologic Unit 21010005, 0.2 mi(0.3 km) downstream of Lago Cidra Dam on right bank, 2.1 mi (3.4 km) northwest of Plaza de Cidra. DRAINAGE AREA.--8.31 mi2 (21.5 km2). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--November 1990 to current year. GAGE.--Water-stage recorder. Elevation of gage is 1,279 ft (390 m), from topographic map. 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. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 34 11 299 23 15 14 16 22 16 17 22 20 2 38 11 523 18 15 15 16 39 13 18 23 20 3 39 10 217 22 13 15 17 27 16 12 24 21 4 39 13 135 22 13 15 16 22 18 12 25 21 5 40 19 38 17 13 15 16 22 18 13 22 21 6 40 19 32 15 13 15 15 23 18 12 22 21 7 38 18 31 13 13 15 9.0 23 19 11 22 21 8 39 19 21 13 12 16 5.0 23 20 14 22 20 9 40 19 20 13 12 17 4.8 23 12 15 20 20 10 39 20 18 14 12 17 6.2 21 8.0 12 21 20 11 40 22 23 16 12 17 5.0 20 7.0 11 21 18 12 41 21 19 15 13 17 4.3 19 7.4 8.5 21 18 13 40 11 17 14 14 17 4.1 16 13 6.4 21 19 14 e36 22 15 14 18 17 4.1 16 16 7.1 21 19 15 26 28 14 48 18 17 4.1 16 18 9.3 21 18 16 24 24 14 31 18 17 12 16 12 7.6 21 18 17 24 26 13 21 17 17 25 21 11 7.8 25 19 18 23 26 13 19 15 17 25 25 8.1 8.1 28 21 19 26 30 13 19 15 17 25 25 7.5 8.4 26 21 20 28 50 15 21 13 17 22 26 7.7 12 24 15 21 27 38 15 35 13 17 18 31 8.3 14 25 12 22 32 27 14 25 13 17 18 34 8.5 14 30 12 23 25 40 12 14 13 17 18 34 9.0 14 20 13 24 24 213 9.9 15 14 17 18 23 9.9 14 16 13 25 27 47 11 15 14 18 18 17 19 14 15 12 26 32 26 11 15 15 18 19 16 19 14 19 13 27 e34 22 11 15 15 19 19 16 20 14 20 13 28 29 22 220 15 14 31 19 16 18 14 21 10 29 22 30 392 15 --- 21 20 18 18 15 21 4.6 30 11 40 49 15 --- 17 20 19 19 21 21 4.9 31 11 --- 33 15 --- 16 --- 20 --- 22 21 --- TOTAL 968 924 2267.9 582 395 532 438.6 689 414.4 392.2 681 498.5 MEAN 31.2 30.8 73.2 18.8 14.1 17.2 14.6 22.2 13.8 12.7 22.0 16.6 MAX 41 213 523 48 18 31 25 39 20 22 30 21 MIN 11 10 9.9 13 12 14 4.1 16 7.0 6.4 15 4.6 AC-FT 1920 1830 4500 1150 783 1060 870 1370 822 778 1350 989 CFSM 3.75 3.70 8.79 2.26 1.70 2.06 1.76 2.67 1.66 1.52 2.64 2.00 IN. 4.33 4.13 10.14 2.60 1.77 2.38 1.96 3.08 1.85 1.75 3.04 2.23 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1991 - 1999, BY WATER YEAR (WY) MEAN 16.1 22.9 22.0 18.5 17.9 17.4 13.8 12.4 11.6 14.0 14.6 45.9 MAX 31.2 41.2 73.2 59.6 36.5 26.3 24.5 23.2 20.6 39.6 29.2 233 (WY) 1999 1992 1999 1992 1991 1998 1996 1998 1998 1993 1996 1996 MIN 3.74 8.85 4.36 5.45 7.24 11.4 5.72 4.13 3.47 1.56 1.18 1.64 (WY) 1995 1995 1994 1995 1994 1994 1997 1993 1994 1994 1995 1994 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1991 - 1999 ANNUAL TOTAL 11990.5 8782.6 ANNUAL MEAN 32.9 24.1 18.9 HIGHEST ANNUAL MEAN 36.1 1996 LOWEST ANNUAL MEAN 5.93 1994 HIGHEST DAILY MEAN 2050 Sep 22 523 Dec 2 5420 Sep 10 1996 LOWEST DAILY MEAN 6.4 Aug 26 4.1 Apr 13 .60 Aug 6 1992 ANNUAL SEVEN-DAY MINIMUM 9.9 Jul 28 4.7 Apr 9 .80 May 1 1995 INSTANTANEOUS PEAK FLOW 1790 Dec 28 15000 Sep 10 1996 INSTANTANEOUS PEAK STAGE 15.92 Dec 28 27.34 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 23780 17420 13710 ANNUAL RUNOFF (CFSM) 3.95 2.89 2.27 ANNUAL RUNOFF (INCHES) 53.61 39.27 30.90 10 PERCENT EXCEEDS 33 32 28 50 PERCENT EXCEEDS 21 18 13 90 PERCENT EXCEEDS 11 11 3.4 e Estimated 166 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 1,000 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 167 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR--Continued 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 observerand 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 1999.-- SEDIMENT CONCENTRATION: Maximum daily mean, 3,140 mg/L November 11,1998; Minimum daily mean, 5 mg/L February 25-26, 1999. SEDIMENT LOADS: Maximum daily mean, 2,730 tons (2,480 tonnes) December 28, 1998; Minimum daily mean, tons 0.20 (0.18 tonne) February 25, 1999. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 34 330 30 11 124 3.6 299 265 270 2 38 282 29 11 124 3.5 523 1200 2310 3 39 238 25 10 123 3.5 217 837 766 4 39 210 22 13 112 3.9 135 2150 904 5 40 190 21 19 121 6.1 38 868 90 6 40 297 35 19 122 6.2 32 365 31 7 38 290 30 18 108 5.4 31 156 13 8 39 238 25 19 102 5.1 21 70 3.9 9 40 242 26 19 98 5.1 20 62 3.3 10 39 261 27 20 94 5.0 18 69 3.4 11 40 256 28 22 3140 213 23 73 4.4 12 41 245 27 21 1700 90 19 74 3.7 13 40 234 25 11 264 8.4 17 63 2.9 14 e36 e208 e20 22 61 3.2 15 51 2.1 15 26 186 13 28 48 3.7 14 42 1.6 16 24 190 12 24 59 3.8 14 48 1.7 17 24 195 13 26 71 4.9 13 57 2.0 18 23 186 12 26 76 5.5 13 60 2.1 19 26 174 12 30 80 6.6 13 64 2.2 20 28 164 12 50 84 11 15 100 4.2 21 27 156 11 38 87 8.9 15 174 6.8 22 32 148 13 27 77 5.6 14 284 11 23 25 144 9.7 40 104 36 12 229 7.4 24 24 148 9.5 213 510 429 9.9 158 4.2 25 27 152 11 47 31 4.1 11 145 4.3 26 32 148 13 26 21 1.5 11 136 4.2 27 e34 e308 e33 22 32 2.0 11 127 3.7 28 29 253 20 22 62 3.7 220 767 2730 29 22 142 8.6 30 77 6.3 392 1040 2110 30 11 125 3.6 40 88 9.6 49 115 15 31 11 124 3.6 --- --- --- 33 84 7.4 TOTAL 968 --- 580.0 924 --- 904.2 2267.9 --- 9325.5 168 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 23 98 6.0 15 34 1.4 14 6 .22 2 18 121 5.9 15 32 1.3 15 6 .24 3 22 122 7.3 13 30 1.0 15 6 .24 4 22 119 7.1 13 28 .96 15 6 .24 5 17 115 5.3 13 25 .86 15 6 .24 6 15 105 4.2 13 22 .75 15 6 .25 7 13 96 3.4 13 20 .69 15 7 .26 8 13 94 3.2 12 19 .61 16 7 .31 9 13 93 3.2 12 17 .57 17 8 .35 10 14 90 3.4 12 16 .54 17 8 .38 11 16 86 3.7 12 15 .50 17 9 .41 12 15 82 3.2 13 17 .61 17 10 .47 13 14 83 3.1 14 20 .75 17 12 .56 14 14 85 3.3 18 21 .98 17 17 .78 15 48 90 12 18 20 .98 17 25 1.1 16 31 94 7.8 18 20 .98 17 35 1.6 17 21 89 5.0 17 19 .86 17 37 1.7 18 19 82 4.1 15 23 .97 17 35 1.6 19 19 71 3.7 15 17 .70 17 21 .97 20 21 62 3.5 13 9 .33 17 11 .51 21 35 66 6.3 13 8 .30 17 10 .48 22 25 74 4.8 13 9 .31 17 11 .49 23 14 82 3.1 13 9 .32 17 11 .51 24 15 78 3.0 14 7 .26 17 11 .53 25 15 71 2.8 14 5 .20 18 12 .59 26 15 65 2.5 15 5 .21 18 17 .83 27 15 68 2.7 15 6 .23 19 25 1.2 28 15 72 3.0 14 6 .23 31 21 1.7 29 15 56 2.2 --- --- --- 21 16 .93 30 15 40 1.6 --- --- --- 17 13 .58 31 15 37 1.4 --- --- --- 16 14 .58 TOTAL 582 --- 131.8 395 --- 18.40 532 --- 20.85 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) APRIL MAY JUNE 1 16 14 .62 22 18 1.1 16 33 1.6 2 16 14 .60 39 20 2.1 13 31 1.1 3 17 13 .61 27 23 1.6 16 27 1.2 4 16 13 .56 22 25 1.5 18 23 1.1 5 16 12 .55 22 21 1.3 18 20 .96 6 15 12 .51 23 16 .99 18 18 .87 7 9.0 14 .35 23 12 .75 19 15 .80 8 5.0 17 .22 23 10 .64 20 15 .82 9 4.8 19 .25 23 11 .71 12 17 .53 10 6.2 30 .74 21 13 .71 8.0 19 .41 11 5.0 25 .34 20 14 .76 7.0 22 .41 12 4.3 21 .24 19 15 .79 7.4 24 .48 13 4.1 22 .24 16 17 .73 13 29 1.1 14 4.1 23 .26 16 18 .79 16 34 1.4 15 4.1 24 .26 16 20 .87 18 27 1.4 16 12 35 1.5 16 23 1.0 12 22 .75 17 25 49 3.3 21 27 1.5 11 101 3.2 18 25 34 2.3 25 25 1.7 8.1 52 1.1 19 25 23 1.6 25 21 1.4 7.5 36 .72 20 22 16 .95 26 18 1.3 7.7 28 .57 21 18 14 .69 31 15 1.3 8.3 22 .48 22 18 14 .70 34 13 1.2 8.5 21 .49 23 18 15 .71 34 13 1.2 9.0 24 .57 24 18 15 .74 23 14 .83 9.9 26 .70 25 18 19 .92 17 14 .64 19 27 1.4 26 19 23 1.2 16 13 .58 19 22 1.1 27 19 20 1.0 16 12 .51 20 20 1.0 28 19 14 .73 16 11 .48 18 18 .92 29 20 14 .75 18 10 .49 18 17 .82 30 20 16 .87 19 10 .49 19 14 .70 31 --- --- --- 20 9 .50 --- --- --- TOTAL 438.6 --- 24.31 689 --- 30.46 414.4 --- 28.70 169 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 17 13 .58 22 18 1.1 20 26 1.4 2 18 630 59 23 17 1.1 20 29 1.6 3 12 28 .94 24 16 1.0 21 32 1.8 4 12 20 .67 25 17 1.1 21 33 1.9 5 13 22 .76 22 18 1.1 21 27 1.5 6 12 30 .98 22 18 1.1 21 21 1.2 7 11 44 1.4 22 19 1.1 21 17 .93 8 14 63 2.5 22 18 1.0 20 15 .81 9 15 91 3.7 20 17 .92 20 14 .74 10 12 125 4.0 21 15 .86 20 13 .69 11 11 127 3.9 21 15 .85 18 12 .58 12 8.5 121 2.8 21 15 .86 18 11 .55 13 6.4 115 2.0 21 15 .85 19 73 4.0 14 7.1 110 2.1 21 15 .85 19 34 1.8 15 9.3 296 36 21 13 .76 18 32 1.5 16 7.6 91 1.8 21 12 .70 18 31 1.6 17 7.8 44 .93 25 11 .76 19 31 1.6 18 8.1 36 .78 28 17 1.4 21 31 1.8 19 8.4 35 .80 26 74 5.4 21 681 70 20 12 33 1.0 24 46 3.0 15 111 4.8 21 14 31 1.2 25 28 1.9 12 44 1.4 22 14 29 1.1 30 1370 202 12 32 1.0 23 14 27 1.0 20 125 6.9 13 30 1.0 24 14 25 .98 16 36 1.6 13 28 .98 25 14 25 .96 15 27 1.1 12 27 .90 26 14 24 .93 19 25 1.3 13 26 .94 27 14 23 .89 20 23 1.2 13 25 .87 28 14 22 .84 21 21 1.2 10 31 1.1 29 15 21 .83 21 21 1.2 4.6 53 .67 30 21 20 1.1 21 21 1.2 4.9 41 .54 31 22 19 1.1 21 23 1.3 --- --- --- TOTAL 392.2 --- 137.57 681 --- 246.71 498.5 --- 110.20 YEAR 8782.6 11558.70 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) OCT 20... 0830 28 165 12 99 DEC 22... 1611 14 328 12 99 FEB 06... 1345 12 22 .71 72 APR 16... 1832 26 65 4.6 89 170 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. SED. CHARGE, MENT, SUSP. SUSP. SUSP. INST. SEDI- DIS- FALL FALL FALL CUBIC MENT, CHARGE, DIAM. DIAM. DIAM. FEET SUS- SUS- % FINER % FINER % FINER DATE TIME PER PENDED PENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) OCT 27... 1630 E62 2430 400 56 66 77 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) OCT 27... 85 93 95 99 100 100 100 171 RIO DE BAYAMON BASIN 50047600 RIO DE BAYAMON NEAR AGUAS BUENAS, PR WATER-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 mi2 (47.9 km2). PERIOD OF RECORD.--Water years 1958-65, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 03... 1345 28 294 8.1 26.5 27 6.8 88 <10 360 370 MAR 04... 1340 26 255 8.1 25.0 3.0 7.7 95 <10 K190 K36 MAY 12... 1730 24 280 7.7 25.5 10 7.9 100 10 K130 360 SEP 01... 1345 29 279 8.4 27.6 4.0 7.4 99 <10 400 K160 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 03... 110 26 11 12 .5 3.1 100 <1.0 9.9 18 MAR 04... -- -- -- -- -- -- 100 -- -- -- MAY 12... 94 21 9.9 15 .7 2.5 93 <1.0 6.3 20 SEP 01... 100 24 11 17 .7 2.3 110 -- 7.9 19 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) NOV 03... <.10 24 164 12.5 17 .964 .016 .980 .030 .25 MAR 04... -- -- -- -- 1 -- <.010 .750 .040 -- MAY 12... <.10 21 151 9.89 5 -- <.010 .460 .020 -- SEP 01... <.10 25 172 13.4 5 -- <.010 .640 .030 .26 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) NOV 03... .28 1.3 5.6 .030 1 <100 20 <1 2 <10 MAR 04... <.20 -- -- .170 -- -- -- -- -- -- MAY 12... E.21 -- -- <.020 <1 20 E30 <1 <1 <10 SEP 01... .29 .93 4.1 <.020 -- -- -- -- -- -- 172 RIO DE BAYAMON BASIN 50047600 RIO DE BAYAMON NEAR AGUAS BUENAS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 03... 1200 <1 49 <.10 <1 <1 <10 <.010 5 <.02 MAR 04... -- -- -- -- -- -- -- -- -- -- MAY 12... 360 <1 65 <.10 <1 <1 <40 <.010 <4 <.02 SEP 01... -- -- -- -- -- -- -- -- -- -- 173 RIO DE 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 quarry near Highway 174, 1.3 mi (2.1km) south of colonia Santa Rosa and 4.7 mi (7.6 km) south of Bayamón. DRAINAGE AREA.--41.8 mi2 (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 except those for estimated daily discharges, which are poor. 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 25 17 871 95 58 48 15 8.9 31 8.8 162 40 2 21 74 1240 81 55 30 27 9.2 12 606 134 27 3 23 25 906 77 29 21 20 9.4 9.6 47 54 27 4 19 18 724 72 27 20 16 9.2 8.9 12 26 46 5 19 15 405 65 26 19 14 9.2 8.7 12 24 26 6 22 14 301 63 e26 18 14 25 8.4 9.5 20 185 7 31 16 219 54 e25 18 13 15 65 9.2 21 104 8 22 14 145 51 25 18 13 110 270 60 19 53 9 19 38 112 51 24 165 13 29 54 233 18 31 10 18 108 84 71 23 32 19 9.1 19 43 18 30 11 17 140 109 75 23 21 27 e8.1 9.8 137 118 66 12 18 508 92 54 37 19 11 e8.3 11 69 21 34 13 18 675 76 50 48 19 11 e8.6 9.3 38 18 34 14 17 164 56 50 25 e19 10 8.0 83 24 18 31 15 16 85 45 225 24 e19 11 7.6 187 212 30 27 16 13 62 43 97 e29 e20 9.7 7.5 222 55 77 26 17 13 53 37 52 e26 20 9.6 7.4 359 142 25 26 18 13 48 34 40 e24 19 10 7.3 99 38 19 27 19 18 47 34 38 e23 18 10 7.3 46 26 17 285 20 15 53 101 36 e23 17 9.7 7.4 44 172 29 138 21 20 71 52 36 e22 17 9.5 7.4 21 75 30 34 22 162 46 40 44 e22 16 9.7 7.3 11 24 177 23 23 114 44 69 33 e21 16 11 7.5 9.8 176 364 23 24 22 135 44 30 20 17 10 7.2 9.1 46 62 103 25 17 81 34 30 21 16 9.7 7.7 8.8 27 28 26 26 130 52 44 37 20 15 9.6 6.8 8.5 24 22 78 27 e469 56 100 30 20 14 9.4 6.6 8.4 23 21 45 28 843 49 233 169 20 14 9.2 6.7 9.0 21 19 36 29 636 81 852 33 --- 14 9.2 26 14 38 42 45 30 166 146 214 28 --- 38 9.2 34 9.9 26 28 23 31 25 --- 130 28 --- 23 --- 85 --- 22 196 --- TOTAL 2981 2935 7446 1895 766 780 379.5 513.7 1666.2 2455.5 1857 1699 MEAN 96.2 97.8 240 61.1 27.4 25.2 12.6 16.6 55.5 79.2 59.9 56.6 MAX 843 675 1240 225 58 165 27 110 359 606 364 285 MIN 13 14 34 28 20 14 9.2 6.6 8.4 8.8 17 23 AC-FT 5910 5820 14770 3760 1520 1550 753 1020 3300 4870 3680 3370 CFSM 2.30 2.34 5.75 1.46 .65 .60 .30 .40 1.33 1.89 1.43 1.35 IN. 2.65 2.61 6.63 1.69 .68 .69 .34 .46 1.48 2.19 1.65 1.51 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1964 - 1999, BY WATER YEAR (WY) MEAN 37.1 45.3 50.7 36.3 23.4 18.1 20.1 36.6 20.6 24.3 42.7 67.3 MAX 129 174 263 159 75.3 52.9 72.7 131 60.8 79.2 137 360 (WY) 1991 1970 1966 1969 1989 1990 1971 1966 1970 1999 1970 1996 MIN 4.30 7.91 3.45 5.30 4.75 3.58 5.36 4.85 3.68 4.01 7.47 6.02 (WY) 1969 1965 1998 1968 1965 1965 1965 1994 1994 1994 1994 1967 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1964 - 1999 ANNUAL TOTAL 24759.4 25373.9 ANNUAL MEAN 67.8 69.5 35.3 HIGHEST ANNUAL MEAN 69.5 1999 LOWEST ANNUAL MEAN 10.9 1994 HIGHEST DAILY MEAN 3640 Sep 22 1240 Dec 2 8640 Sep 10 1996 LOWEST DAILY MEAN 2.5 Jan 2 6.6 May 27 2.2 Apr 19 1965 ANNUAL SEVEN-DAY MINIMUM 4.6 Jan 28 7.1 May 22 2.4 Apr 14 1965 INSTANTANEOUS PEAK FLOW 5240 Oct 28 65000 Sep 10 1996 INSTANTANEOUS PEAK STAGE 11.69 Oct 28 29.07 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 49110 50330 25590 ANNUAL RUNOFF (CFSM) 1.62 1.66 .84 ANNUAL RUNOFF (INCHES) 22.03 22.58 11.48 10 PERCENT EXCEEDS 118 152 60 50 PERCENT EXCEEDS 11 26 13 90 PERCENT EXCEEDS 6.2 9.3 5.0 e Estimated 174 RIO DE BAYAMON BASIN 50047850 RIO BAYAMON NR BAYAMON, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 10,000 2 5 10 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 175 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 Río de Bayamón, and 2.3 mi (3.7 km) southeast of Bayamón plaza. DRAINAGE AREA.--73.2 mi2 (189.6 km2). PERIOD OF RECORD.--Water years 1958, 1964, 1971-73, 1976, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) DEC 15... 1145 59 435 7.6 27.0 8.0 6.6 82 <10 75000 7100 FEB 23... 1510 -- 465 8.1 27.0 17 4.9 61 <10 2400 520 JUN 04... 1045 -- 46 -- 27.6 16 4.2 53 11 2400 550 AUG 23... 1120 1140 118 7.7 25.5 410 6.4 78 92 230000 210000 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) DEC 15... 160 44 13 23 .8 3.2 160 <1.0 12 31 FEB 23... -- -- -- -- -- -- 171 -- -- -- JUN 04... 170 47 13 26 .9 3.2 166 <1.0 18 34 AUG 23... 37 11 2.7 5.7 .4 1.6 51 -- 3.8 6.0 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) DEC 15... .15 29 252 40.0 17 1.02 .083 1.10 .260 .30 FEB 23... -- -- -- -- 23 .796 .054 .850 .150 .32 JUN 04... .17 27 269 -- 64 .550 .030 .580 .090 -- AUG 23... <.10 7.1 68 209 1220 .270 .040 .310 .160 2.8 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) DEC 15... .56 1.7 7.3 .160 <1 <100 30 <1 <1 <10 FEB 23... .47 1.3 5.8 .150 -- -- -- -- -- -- JUN 04... E.51 -- -- E.160 <1 100 60 <1 <1 E12 AUG 23... 3.0 3.3 15 1.30 -- -- -- -- -- -- 176 RIO DE BAYAMON BASIN 50047990 RIO GUAYNABO NEAR BAYAMON, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) DEC 15... 500 <1 130 <.10 <1 <1 <10 <.010 -- .07 FEB 23... -- -- -- -- -- -- -- -- -- -- JUN 04... 820 <1 150 <.10 <1 <1 <40 <.010 7 .24 AUG 23... -- -- -- -- -- -- -- -- -- -- 177 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 mi2 (186.2 km2). 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 1998 TO SEPTEMBER 1999 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) DEC 15... 0930 134 420 7.7 25.0 4.4 7.3 88 <10 58000 2600 MAR 15... 1215 39 437 7.4 28.4 6.2 5.3 68 <10 2700 64 JUN 07... 1230 14 481 8.1 30.5 10 6.9 92 32 K1200 K20 AUG 23... 0945 174 278 7.7 25.9 -- 7.5 99 17 27000 44000 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) DEC 15... 160 42 14 21 .7 2.8 150 <1.0 12 28 MAR 15... -- -- -- -- -- -- 162 -- -- -- JUN 07... 180 49 15 29 .9 2.5 174 <1.0 14 43 AUG 23... 99 25 8.7 15 .6 2.7 96 -- 9.8 19 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) DEC 15... .14 27 237 85.7 1 .826 .034 .860 .070 .27 MAR 15... -- -- -- -- 7 .444 .026 .470 .180 -- JUN 07... .28 27 283 10.6 11 -- <.010 .050 .030 -- AUG 23... .11 21 159 74.8 170 .790 .040 .830 .100 .83 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) DEC 15... .34 1.2 5.3 .080 <1 <100 20 <1 <1 10 MAR 15... E.43 -- -- E.110 -- -- -- -- -- -- JUN 07... E.55 -- -- E.070 <1 80 60 <1 <1 E9 AUG 23... .93 1.8 7.8 .200 -- -- -- -- -- -- 178 RIO DE BAYAMON BASIN 50048510 RIO DE BAYAMON AT FLOOD CHANNEL AT BAYAMON, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) DEC 15... 400 <1 150 <.10 <1 <1 10 <.010 <1 .07 MAR 15... -- -- -- -- -- -- -- -- -- -- JUN 07... 480 <1 310 <.10 <1 <1 <40 <.010 5 <.13 AUG 23... -- -- -- -- -- -- -- -- -- -- PESTICIDE ANALYSES CHLOR- DANE, P,P'- P,P'- ENDO- TECH- DDD P,P'- DDT DI- DI- SULFAN PCB, ALDRIN, NICAL UNFILT DDE, UNFILT AZINON, ELDRIN I DATE TIME TOTAL TOTAL TOTAL RECOVER TOTAL RECOVER TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) JUN 1999 07... 1230 <.100 <.010 <.100 <.010 <.010 <.010 .012 <.010 <.010 ENDRIN HEPTA- METH- METHYL METHYL WATER HEPTA- CHLOR MALA- OXY- PARA- TRI- UNFLTRD ETHION, CHLOR, EPOXIDE LINDANE THION, CHLOR, THION, THION, MIREX, DATE REC TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39390) (39398) (39410) (39420) (39340) (39530) (39480) (39600) (39790) (39755) JUN 1999 07... <.010 <.010 <.010 <.010 <.010 .015 <.010 <.010 -- <.010 PARA- PCNS PER- TOX- TOTAL THION, UNFILT THANE APHENE, TRI- 2,4-D, 2,4,5-T 2,4-DP SILVEX, DATE TOTAL RECOVER TOTAL TOTAL THION TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39540) (39250) (39034) (39400) (39786) (39730) (39740) (82183) (39760) JUN 1999 07... <.010 <.100 <.100 <1.00 <.010 .098 <.010 <.010 <.010 1 179 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 Río Piedras, 4.15 mi (6.67 km) south of University of Puerto Rico Tower, 1.6 mi (2.57 km) northwest from Escuela José F. Díaz and 0.8 mi (1.28 km) north of Escuela Cupey Alto. DRAINAGE AREA.--0.97 mi2 (2.51 km2). ELEVATION RECORDS PERIOD OF RECORD.--April 1997 to current year. 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 ft3/s (141.6 m3/s) at reservoir elevation 321.5 ft (98.0 m). This dam is operated by Puerto Rico Aqueduct and Sewer Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 317.01 ft (96.62 m),Aug. 11, 1998; minimum elevation, 313.04 ft (95.41 m), Oct. 5, 1998. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 316.86 ft (96.56 m), Oct. 29; minimum elevation, 313.06 ft (95.41 m), Oct. 5. 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 284.7 154 313.0 677 298.2 462 314.3 1,078 307.1 770 317.5 1,232 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY OBSERVATION AT 2400 HOURS DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 313.89 316.18 315.94 315.87 A A A 315.71 315.95 315.86 315.88 315.84 2 313.65 316.21 316.03 315.88 A A A 315.70 315.91 315.91 315.85 315.84 3 313.41 316.20 315.92 315.88 A A A 315.70 315.87 315.87 315.86 315.89 4 313.16 316.27 315.91 315.87 315.86 A A 315.69 315.88 315.87 315.87 315.86 5 313.06 316.29 315.94 315.89 315.84 A A 315.68 315.86 315.87 315.88 315.87 6 313.11 316.28 315.87 315.88 315.85 A A 315.68 315.85 315.85 315.86 315.86 7 313.13 316.27 315.86 315.88 315.85 A A 315.83 315.87 315.85 A 315.89 8 313.16 316.28 315.86 315.88 315.85 A A 315.86 315.90 315.86 315.86 315.85 9 313.18 316.31 315.86 315.88 A A A 315.80 315.95 315.87 A 315.97 10 313.20 316.30 315.88 315.94 A A A 315.79 315.89 315.85 A 315.87 11 313.23 316.32 315.88 315.88 A A A 315.80 315.87 315.86 A 315.90 12 313.20 316.46 315.87 315.88 315.85 A A 315.80 315.96 315.85 A 315.85 13 313.22 316.00 315.86 315.88 A A A 315.78 315.88 315.86 A 315.84 14 313.22 315.95 315.86 315.93 315.84 A A 315.77 315.87 315.88 315.90 315.85 15 313.25 315.94 315.89 315.90 315.84 A A 315.76 315.87 A A 315.84 16 313.27 315.97 315.89 315.90 315.84 A A 315.75 315.87 315.88 A 315.85 17 313.31 315.89 315.88 315.88 315.85 A A 315.74 315.89 315.87 A 315.84 18 313.33 315.89 315.88 315.88 A A A 315.74 315.88 315.85 A 315.91 19 313.36 315.90 315.90 315.88 A A 315.73 315.88 315.85 A 315.87 20 313.38 315.89 315.91 315.87 315.86 A A 315.73 315.88 A A 315.88 21 313.72 315.86 315.89 315.89 315.86 A A 315.73 315.86 315.85 A 315.86 22 316.09 315.84 315.92 315.88 A A A 315.74 315.87 315.87 A 315.84 23 316.06 315.85 315.98 315.88 A A A 315.76 315.85 315.94 A 315.85 24 316.10 315.85 315.89 315.86 A 315.86 A 315.75 315.84 315.87 A 315.85 25 316.16 315.83 315.89 315.89 A 315.86 A A 315.82 A A 315.86 26 316.06 315.83 315.89 315.87 A 315.84 A A A A 315.85 315.89 27 316.17 315.91 315.89 315.86 A 315.83 315.76 315.78 A A 315.84 315.87 28 316.02 315.85 316.07 315.87 A 315.83 315.74 A A A 315.85 315.87 29 316.08 315.86 315.89 A --- A 315.74 315.89 315.90 A 315.86 315.87 30 315.95 315.88 315.89 A --- A 315.72 315.89 315.85 315.85 315.85 315.86 31 316.25 --- 315.88 --- --- A --- 315.91 --- 315.85 315.86 --- MAX 316.25 316.46 316.07 --- --- --- --- --- --- --- --- 315.97 MIN 313.06 315.83 315.86 --- --- --- --- --- --- --- --- 315.84 A No gage-height record 180 RIO PUERTO NUEVO BASIN 50048690 QUEBRADA LAS CURIAS BELOW LAS CURIAS DAM, PR LOCATION.--Lat 18°20'43", long 66°03'08", Hydrologic Unit 21010005, at 0.20 miles from Lago Las Curias Dam on Río Piedras, 4.13 mi (6.64 km) south of University of Puerto Rico Tower, 2.55 mi (4.10 km) northwest from Lago Loíza spillway crest and 0.85 mi (1.37 km) north of Escuela Cupey Alto. DRAINAGE AREA.--1.08 mi2 (2.79 km2). PERIOD OF RECORD.--August 1997 to current year. GAGE.--Water stage recorder. Elevation of gage is 262.47 ft (80.0 km), from topographic map. REMARKS.--Records poor. Flow completly regulated by Lago Las Curias Dam, 0.20 mi (0.32 km) from gage. Gage-height and precipitation 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 .57 2 .73 3 .78 4 .66 5 .41 6 .36 7 .27 .37 8 .30 .39 9 .29 .43 10 .32 .60 11 .41 .72 12 .36 .59 13 10 2.0 14 7.2 7.4 15 2.1 2.1 16 1.0 1.1 17 2.2 .71 18 3.1 .74 19 .51 .45 20 .31 .43 21 10 .33 22 21 .38 23 5.0 .52 24 7.3 .68 25 5.2 .59 26 1.6 2.3 27 .59 .86 28 .42 .31 29 .31 2.0 30 .30 1.3 31 .38 --- TOTAL --- 30.81 MEAN --- 1.03 MAX --- 7.4 MIN --- .31 AC-FT --- 61 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1997 - 1997, BY WATER YEAR (WY) MEAN --- 1.03 MAX --- 1.03 (WY) --- 1997 MIN --- 1.03 (WY) --- 1997 181 RIO PUERTO NUEVO BASIN 50048690 QUEBRADA LAS CURIAS BELOW LAS CURIAS DAM, PR--Continued O N D J F M A M J J A S 1996 1997 WATER YEAR 0.1 100 0.2 0.5 1 2 5 10 20 50 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 182 RIO PUERTO NUEVO BASIN 50048690 QUEBRADA LAS CURIAS BELOW LAS CURIAS DAM, PR--continued DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1997 TO SEPTEMBER 1998 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 1.7 .52 .76 e.61 .42 .38 .42 .26 .40 .18 .30 4.8 2 15 .50 .57 e.61 .40 .35 .39 .25 .25 .19 .28 .55 3 6.4 .62 .55 e.70 .48 .33 .28 .27 .24 .24 .30 .37 4 1.1 .66 .56 e.64 2.9 .33 .30 .27 .25 1.4 .33 .40 5 .64 .98 .57 e.66 18 .34 .36 .28 2.0 .83 .36 .43 6 .71 .59 .55 e1.9 1.6 .30 .29 .26 1.5 .23 e.40 36 7 .71 .62 .59 e2.1 1.1 .32 .32 .25 .60 .58 1.7 10 8 14 .56 .54 e.58 3.2 .34 .33 .25 .30 .29 1.6 2.8 9 6.1 .81 .49 e.56 4.2 .33 .25 .25 2.0 .33 .62 2.3 10 1.5 .86 .45 e.52 .56 .27 .23 .25 2.0 .23 3.9 1.7 11 .88 .69 .45 e.48 .47 .28 .24 .26 .42 .25 46 .84 12 6.3 .68 .45 e.55 .56 .29 .58 .26 .28 .28 12 1.6 13 6.4 .72 .44 e1.9 e.55 .29 1.5 .27 .25 .22 2.8 3.2 14 31 .80 .47 e1.2 1.8 .34 .43 .32 .31 .18 1.2 2.4 15 3.1 1.8 .47 e.90 2.2 .29 .48 .25 .26 .20 .91 1.6 16 1.7 2.6 .47 .79 1.0 .30 9.2 .27 .26 9.4 .74 2.1 17 .95 .84 .46 .55 1.1 .35 2.3 .27 .37 2.0 .60 5.9 18 1.2 .97 .50 2.8 .84 .39 .45 .26 e.91 1.5 5.8 9.6 19 .94 1.4 .49 1.6 .61 .31 .44 .26 .55 .81 3.2 15 20 .60 .80 e.48 .50 .40 .30 1.3 .26 .38 4.3 1.1 15 21 .53 2.7 e.69 .58 .46 .35 .86 .27 .28 2.5 6.7 37 22 .61 1.5 e.47 .57 .38 .32 .67 .28 .30 .65 7.9 96 23 .59 .81 e.44 .42 .48 .29 .47 .34 .23 .54 7.7 19 24 .71 .56 e.49 .48 .38 .28 e.36 .38 .22 1.6 7.8 14 25 .62 .59 e.47 .56 .34 .28 e.30 .32 .21 .70 7.7 14 26 .62 .76 e.48 .51 .36 .31 e.27 .32 .20 .47 7.6 14 27 .63 .64 e.48 .59 .38 .32 .28 .47 .20 .49 7.9 14 28 .52 .62 e.47 .48 .38 .31 .28 .34 .20 .51 53 14 29 .53 .63 e.49 .46 --- .50 .29 .31 .18 .40 11 13 30 .51 .76 e.51 .42 --- .28 .31 .32 .19 .41 8.9 13 31 .54 --- e.57 .42 --- .42 --- .30 --- .30 8.4 --- TOTAL 107.34 27.59 15.87 25.64 45.55 10.09 24.18 8.92 15.74 32.21 218.74 364.59 MEAN 3.46 .92 .51 .83 1.63 .33 .81 .29 .52 1.04 7.06 12.2 MAX 31 2.7 .76 2.8 18 .50 9.2 .47 2.0 9.4 53 96 MIN .51 .50 .44 .42 .34 .27 .23 .25 .18 .18 .28 .37 AC-FT 213 55 31 51 90 20 48 18 31 64 434 723 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1997 - 1998, BY WATER YEAR (WY) MEAN 3.46 .92 .51 .83 1.63 .33 .81 .29 .52 1.04 7.06 6.59 MAX 3.46 .92 .51 .83 1.63 .33 .81 .29 .52 1.04 7.06 12.2 (WY) 1998 1998 1998 1998 1998 1998 1998 1998 1998 1998 1998 1998 MIN 3.46 .92 .51 .83 1.63 .33 .81 .29 .52 1.04 7.06 1.03 (WY) 1998 1998 1998 1998 1998 1998 1998 1998 1998 1998 1998 1997 SUMMARY STATISTICS FOR 1998 WATER YEAR WATER YEARS 1997 - 1998 ANNUAL TOTAL 896.46 ANNUAL MEAN 2.46 2.46 HIGHEST ANNUAL MEAN 2.46 1998 LOWEST ANNUAL MEAN 2.46 1998 HIGHEST DAILY MEAN 96 Sep 22 96 Sep 22 1998 LOWEST DAILY MEAN .18 Jun 29 .18 Jun 29 1998 ANNUAL SEVEN-DAY MINIMUM .19 Jun 26 .19 Jun 26 1998 INSTANTANEOUS PEAK FLOW 431 Sep 22 431 Sep 22 1998 INSTANTANEOUS PEAK STAGE 11.70 Sep 22 11.70 Sep 22 1998 ANNUAL RUNOFF (AC-FT) 1780 1780 10 PERCENT EXCEEDS 6.3 6.4 50 PERCENT EXCEEDS .52 .54 90 PERCENT EXCEEDS .26 .27 e Estimated 183 RIO PUERTO NUEVO BASIN 50048690 QUEBRADA LAS CURIAS BELOW LAS CURIAS DAM, PR--continued O N D J F M A M J J A S 1997 1998 WATER YEAR 0.1 100 0.2 0.5 1 2 5 10 20 50 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 184 RIO PUERTO NUEVO BASIN 50048690 QUEBRADA LAS CURIAS BELOW LAS CURIAS DAM, PR--Continued DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 13 3.1 24 2.2 5.2 4.9 .75 .42 35 .66 .43 1.1 2 13 5.5 32 2.8 4.1 12 11 .41 7.5 28 .65 .63 3 13 4.6 35 2.5 2.7 4.8 3.4 .41 2.2 3.3 .62 3.7 4 13 2.7 39 2.2 2.7 1.7 .68 .37 1.6 .84 .69 1.6 5 6.0 2.1 29 2.6 2.2 1.3 2.2 .32 1.1 1.3 2.8 1.7 6 .18 1.2 15 6.3 2.2 1.2 .79 .31 .53 1.3 1.4 1.3 7 .17 .85 8.3 2.4 2.2 1.2 .91 1.2 .38 .81 .80 8.5 8 .18 .84 5.4 2.6 2.0 .95 1.1 9.7 1.7 1.1 .81 1.9 9 .19 4.5 5.0 2.5 2.3 1.2 1.3 2.6 19 1.4 1.3 5.4 10 .24 5.0 6.9 15 2.7 2.5 1.0 .66 4.7 1.0 .77 5.6 11 .25 7.6 12 8.5 2.4 1.6 .71 .51 1.3 1.6 .83 13 12 .25 23 6.1 3.8 3.4 1.4 .61 .70 11 1.1 .79 3.2 13 .24 37 4.6 3.6 3.9 .92 .58 .69 5.3 .63 6.6 1.6 14 .25 7.5 3.5 3.8 2.6 1.3 .72 .68 .98 2.1 12 .69 15 .22 4.1 2.3 11 2.6 1.5 1.0 .55 .68 11 3.6 .63 16 .19 5.0 5.7 8.8 2.2 .96 .96 .41 .59 7.3 1.5 .39 17 .20 2.6 2.0 5.7 1.9 .84 .91 .35 1.6 2.7 12 .36 18 .19 1.8 1.5 3.6 1.6 .98 .49 .28 1.3 1.6 3.2 1.3 19 .21 1.9 2.3 3.6 1.3 1.1 .65 .39 .94 .82 1.4 2.4 20 .21 4.7 5.7 3.3 1.1 1.1 .87 .41 .96 .89 1.4 1.8 21 .32 5.5 3.6 3.3 1.0 14 .73 .30 1.1 1.9 1.4 1.3 22 8.5 3.4 5.3 3.9 1.4 3.8 1.8 .31 .56 1.6 1.6 .76 23 8.0 8.6 11 4.6 1.3 .95 .60 .52 .76 24 2.5 .33 24 1.9 9.3 8.5 4.5 1.3 .68 .54 .40 .67 5.0 1.9 .45 25 3.2 3.5 4.6 3.3 1.8 .81 .43 .40 .58 1.4 1.0 .66 26 1.9 2.5 6.4 5.0 7.6 1.1 .40 .35 .57 1.1 .61 3.2 27 18 17 2.7 3.0 3.0 .69 .41 .34 .43 1.1 .76 3.6 28 31 13 8.9 11 1.5 .72 .42 .36 .42 .62 .87 3.2 29 34 6.4 14 3.3 --- 8.9 .63 3.7 3.8 .58 .87 1.1 30 11 14 3.3 2.6 --- 2.3 .55 9.7 2.1 1.0 .90 .94 31 4.0 --- 2.5 2.2 --- .70 --- 8.6 --- 1.1 .52 --- TOTAL 182.99 208.79 316.1 143.5 70.2 78.10 37.14 46.35 109.35 108.85 66.52 72.34 MEAN 5.90 6.96 10.2 4.63 2.51 2.52 1.24 1.50 3.64 3.51 2.15 2.41 MAX 34 37 39 15 7.6 14 11 9.7 35 28 12 13 MIN .17 .84 1.5 2.2 1.0 .68 .40 .28 .38 .58 .43 .33 AC-FT 363 414 627 285 139 155 74 92 217 216 132 143 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1997 - 1999, BY WATER YEAR (WY) MEAN 4.68 3.94 5.35 2.73 2.07 1.42 1.02 .89 2.08 2.28 4.60 5.20 MAX 5.90 6.96 10.2 4.63 2.51 2.52 1.24 1.50 3.64 3.51 7.06 12.2 (WY) 1999 1999 1999 1999 1999 1999 1999 1999 1999 1999 1998 1998 MIN 3.46 .92 .51 .83 1.63 .33 .81 .29 .52 1.04 2.15 1.03 (WY) 1998 1998 1998 1998 1998 1998 1998 1998 1998 1998 1999 1997 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1997 - 1999 ANNUAL TOTAL 1453.54 1440.23 ANNUAL MEAN 3.98 3.95 3.20 HIGHEST ANNUAL MEAN 3.95 1999 LOWEST ANNUAL MEAN 2.46 1998 HIGHEST DAILY MEAN 96 Sep 22 39 Dec 4 96 Sep 22 1998 LOWEST DAILY MEAN .17 Oct 7 .17 Oct 7 .17 Oct 7 1998 ANNUAL SEVEN-DAY MINIMUM .19 Jun 26 .21 Oct 6 .19 Jun 26 1998 INSTANTANEOUS PEAK FLOW 326 Jun 1 431 Aug 11 1998 INSTANTANEOUS PEAK STAGE 11.08 Jun 1 11.70 Aug 11 1998 ANNUAL RUNOFF (AC-FT) 2880 2860 2320 10 PERCENT EXCEEDS 12 11 8.4 50 PERCENT EXCEEDS .56 1.6 .83 90 PERCENT EXCEEDS .25 .41 .29 185 RIO PUERTO NUEVO BASIN 50048690 QUEBRADA LAS CURIAS BELOW LAS CURIAS DAM, PR--Contined--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 0.1 100 0.2 0.5 1 2 5 10 20 50 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 186 RIO PUERTO NUEVO BASIN 50048770 RIO PIEDRAS AT EL SEÑORIAL, PR LOCATION.--Lat 18°21'51", long 66°03'56", Hydrologic Unit 21010005, on right bank, in the Riberas of Señorial Housing area, 0.6 mi (1.0 km) west of Highway 176 and 2.7 mi (4.3 km)southwest of Río Piedras Plaza. DRAINAGE AREA.--7.49 mi2 (19.40 km2). WATER DISCHARGE RECORDS PERIOD OF RECORDS.--March 1988 to current year. GAGE.--Water-stage recorder. Elevation of gage is 98.4 ft (30.0 m), from topographic map. REMARKS.--Records poor. Low flow is affected by discharges from water treatment plant of PRASA and others dispersed pollution points directly to the rivr. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 10 27 151 21 31 46 8.1 5.8 168 6.3 8.6 13 2 9.6 38 184 30 17 70 77 5.5 50 179 9.5 9.7 3 9.4 24 246 18 14 17 16 5.4 14 17 8.6 106 4 9.3 18 229 17 e14 11 9.7 5.4 18 8.9 8.5 19 5 9.0 17 178 22 e14 10 14 5.2 7.4 10 39 19 6 8.5 16 80 37 e14 9.9 8.9 5.4 6.3 8.3 14 16 7 8.3 17 56 17 e13 9.6 8.4 36 9.6 7.7 13 57 8 9.1 16 43 16 e13 9.2 10 70 24 13 12 15 9 9.6 26 35 18 e14 13 17 12 116 20 9.7 27 10 11 50 30 91 e14 15 14 7.7 26 8.0 8.7 28 11 9.2 61 50 33 14 10 8.6 7.0 9.9 23 22 63 12 8.9 135 28 19 26 9.5 8.0 7.2 84 8.6 11 17 13 8.3 123 23 17 21 9.0 8.0 6.9 27 35 60 12 14 e8.2 56 19 19 15 8.9 8.8 6.6 9.3 22 35 9.8 15 8.5 41 15 76 15 9.5 8.6 6.1 8.8 77 13 9.1 16 7.4 31 44 38 13 8.4 7.5 5.6 8.2 65 17 8.6 17 14 27 25 22 12 8.1 7.2 5.7 20 34 84 8.8 18 7.8 24 18 18 12 8.1 7.7 5.7 10 14 17 15 19 9.2 24 28 21 12 12 7.3 5.6 10 10 14 21 20 8.4 30 42 19 14 8.2 6.8 5.4 12 11 7.5 37 21 65 35 25 21 13 145 6.6 5.3 7.9 26 11 12 22 266 24 47 16 14 16 9.3 16 26 24 61 10 23 70 24 74 21 12 10 8.3 5.9 9.3 151 35 8.5 24 44 e34 44 21 10 10 6.6 5.8 6.9 e18 11 11 25 54 25 38 19 16 10 6.4 6.0 6.7 e12 9.1 19 26 49 17 57 25 31 9.9 6.3 5.0 6.1 e14 9.0 54 27 e194 58 35 17 14 8.8 6.2 4.8 6.1 e12 7.6 51 28 305 44 80 65 11 8.3 6.0 7.5 15 10 9.7 38 29 264 45 71 17 --- 82 6.0 48 34 17 16 14 30 65 69 36 15 --- 13 6.2 62 8.7 12 8.0 11 31 41 --- 25 13 --- 9.0 --- 34 --- 9.7 17 --- TOTAL 1600.7 1176 2056 819 433 624.4 329.5 420.5 765.2 883.5 606.5 739.5 MEAN 51.6 39.2 66.3 26.4 15.5 20.1 11.0 13.6 25.5 28.5 19.6 24.6 MAX 305 135 246 91 31 145 77 70 168 179 84 106 MIN 7.4 16 15 13 10 8.1 6.0 4.8 6.1 6.3 7.5 8.5 AC-FT 3170 2330 4080 1620 859 1240 654 834 1520 1750 1200 1470 CFSM 6.89 5.23 8.85 3.53 2.06 2.69 1.47 1.81 3.41 3.81 2.61 3.29 IN. 7.95 5.84 10.21 4.07 2.15 3.10 1.64 2.09 3.80 4.39 3.01 3.67 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1988 - 1999, BY WATER YEAR (WY) MEAN 26.8 22.4 19.0 15.2 12.9 11.5 11.6 14.2 12.4 15.5 21.5 31.8 MAX 57.3 59.8 66.3 26.4 23.6 20.1 23.9 47.2 25.5 38.0 66.9 80.8 (WY) 1991 1993 1999 1999 1991 1999 1993 1992 1999 1993 1992 1998 MIN 8.48 5.93 4.32 6.95 2.70 1.85 2.83 3.38 2.66 4.22 6.60 6.90 (WY) 1992 1996 1996 1995 1996 1996 1995 1994 1994 1994 1990 1991 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1988 - 1999 ANNUAL TOTAL 9736.7 10453.8 ANNUAL MEAN 26.7 28.6 17.8 HIGHEST ANNUAL MEAN 28.6 1999 LOWEST ANNUAL MEAN 7.76 1994 HIGHEST DAILY MEAN 1030 Sep 22 305 Oct 28 1650 Sep 10 1996 LOWEST DAILY MEAN 3.0 Feb 1 4.8 May 27 .84 Aug 13 1995 ANNUAL SEVEN-DAY MINIMUM 3.3 Jan 28 5.6 Apr 30 .97 Jun 30 1996 INSTANTANEOUS PEAK FLOW 5280 Oct 28 5390 Sep 10 1996 INSTANTANEOUS PEAK STAGE 15.35 Oct 28 15.46 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 19310 20740 12860 ANNUAL RUNOFF (CFSM) 3.56 3.82 2.37 ANNUAL RUNOFF (INCHES) 48.36 51.92 32.20 10 PERCENT EXCEEDS 52 64 36 50 PERCENT EXCEEDS 8.3 14 8.0 90 PERCENT EXCEEDS 3.9 7.1 2.7 e Estimated 187 RIO PUERTO NUEVO BASIN 50048770 RIO PIEDRAS AT EL SEÑORIAL, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 1,000 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 188 RIO PUERTO NUEVO BASIN 50048800 RIO PIEDRAS NEAR RIO PIEDRAS, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°22'15", long 66°03'40", at bridge on Winston Churchill Avenue in the El Señorial Housing area, 0.5 mi (0.8 km) west of Highway 176, and 2.5 mi (4.0 km) southwest of Río Piedras plaza. DRAINAGE AREA.--8.17 mi2 (20.9 km2). PERIOD OF RECORD.--Water years 1972 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) DEC 18... 1045 19 443 7.6 26.0 4.4 6.0 74 <10 >60000 84000 MAR 04... 1530 9.2 443 8.0 26.6 7.5 6.8 83 <10 K1500 K2000 JUN 08... 1130 8.1 475 7.9 29.2 1.5 4.6 59 56 60000 60000 SEP 20... 0945 9.2 415 8.0 26.3 19 7.1 88 <10 38000 55000 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) DEC 18... 150 39 13 28 1 2.9 150 E1.0 18 33 MAR 04... -- -- -- -- -- -- 156 -- -- -- JUN 08... 160 40 13 30 1 3.3 169 <1.0 17 37 SEP 20... 140 37 13 24 .9 2.7 150 -- 14 29 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) DEC 18... .15 37 260 13.1 2 1.13 .069 1.20 1.50 .60 MAR 04... -- -- -- -- 11 1.07 .029 1.10 .190 -- JUN 08... .17 2.5 245 5.37 57 .690 .080 .770 2.50 -- SEP 20... .13 32 242 6.03 9 .960 .140 1.10 1.50 .00 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) DEC 18... 2.1 3.3 15 .200 3 <100 20 <1 1 <10 MAR 04... E.58 -- -- E.430 -- -- -- -- -- -- JUN 08... E3.1 -- -- E.420 1 100 80 <1 <1 E12 SEP 20... 1.5 2.6 12 .230 -- -- -- -- -- -- 189 RIO PUERTO NUEVO BASIN 50048800 RIO PIEDRAS NEAR RIO PIEDRAS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) DEC 18... 260 <1 100 <.10 <1 <1 20 .160 <4 .28 MAR 04... -- -- -- -- -- -- -- -- -- -- JUN 08... 1100 <1 170 <.10 1 <1 <40 <.010 <4 .08 SEP 20... -- -- -- -- -- -- -- -- -- -- PESTICIDE ANALYSES CHLOR- DANE, P,P'- P,P'- ENDO- TECH- DDD P,P'- DDT DI- DI- SULFAN PCB, ALDRIN, NICAL UNFILT DDE, UNFILT AZINON, ELDRIN I DATE TIME TOTAL TOTAL TOTAL RECOVER TOTAL RECOVER TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) JUN 1999 08... 1130 <.100 <.010 <.100 <.010 <.010 <.010 .053 <.010 <.010 ENDRIN HEPTA- METH- METHYL METHYL WATER HEPTA- CHLOR MALA- OXY- PARA- TRI- UNFLTRD ETHION, CHLOR, EPOXIDE LINDANE THION, CHLOR, THION, THION, MIREX, DATE REC TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39390) (39398) (39410) (39420) (39340) (39530) (39480) (39600) (39790) (39755) JUN 1999 08... <.010 <.010 <.010 <.010 <.010 <.010 <.010 <.010 -- <.010 PARA- PCNS PER- TOX- TOTAL THION, UNFILT THANE APHENE, TRI- 2,4-D, 2,4,5-T 2,4-DP SILVEX, DATE TOTAL RECOVER TOTAL TOTAL THION TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39540) (39250) (39034) (39400) (39786) (39730) (39740) (82183) (39760) JUN 1999 08... <.010 <.100 <.100 <1.00 <.010 <.010 <.010 <.010 <.010 190 RIO PUERTO NUEVO BASIN 50049100 RIO PIEDRAS AT HATO REY, PR LOCATION.--Lat 18°24'34", long 66°04'10", Hydrologic Unit 21010005, at bridge on Avenida Piñeiro near Expreso Las Américas (Luis A. Ferré), and 0.8 mi (1.3 km) southwest of Hato Rey. DRAINAGE AREA.--15.4 mi2 (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 ft3/s (0.06 m3/s), 20 ft (6 m) upstream from gaging station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e204 e87 236 43 42 119 21 14 183 20 20 32 2 e116 e235 218 58 27 150 90 13 185 287 21 29 3 e109 e134 602 41 26 28 28 13 28 28 45 119 4 e102 e61 327 e45 28 21 21 13 167 22 55 37 5 e110 e30 232 e55 26 21 24 15 29 27 39 35 6 e90 31 80 e60 25 20 21 64 23 21 21 35 7 e86 32 59 38 25 20 20 103 27 21 22 59 8 e85 31 47 39 24 19 41 126 36 25 19 34 9 e80 61 45 39 25 21 29 25 164 e34 18 37 10 e81 67 44 119 e26 25 46 20 41 e21 18 39 11 e72 131 69 41 25 19 18 33 26 e37 22 112 12 e74 202 41 33 48 19 16 18 212 e22 19 25 13 e63 332 43 36 32 18 16 17 42 e49 102 22 14 e59 63 38 35 23 18 16 16 24 e36 27 19 15 e57 66 37 69 23 18 17 15 23 92 19 61 16 e51 51 52 56 22 18 15 15 23 45 21 22 17 e62 38 42 31 22 17 15 15 31 48 135 21 18 e52 36 35 33 21 17 15 14 48 23 24 21 19 e62 36 51 31 22 20 15 14 32 20 113 31 20 e57 44 60 36 21 17 15 14 33 21 25 61 21 e139 48 47 38 21 183 14 14 22 27 34 25 22 e721 38 77 28 21 41 17 28 30 26 140 22 23 e119 48 86 31 21 28 21 18 22 264 178 20 24 e64 65 56 33 21 28 15 14 20 42 44 23 25 e86 38 64 38 40 44 14 14 19 27 45 23 26 e70 33 83 35 72 26 14 13 19 33 82 72 27 e502 58 47 28 23 25 16 13 19 25 32 55 28 e698 54 183 95 20 32 14 22 35 23 30 41 29 e603 48 106 28 --- 84 14 41 33 26 40 21 30 e95 91 70 26 --- 25 14 43 21 83 28 18 31 e71 --- 48 26 --- 22 --- 82 --- 22 30 --- TOTAL 4840 2289 3225 1344 772 1163 652 879 1617 1497 1468 1171 MEAN 156 76.3 104 43.4 27.6 37.5 21.7 28.4 53.9 48.3 47.4 39.0 MAX 721 332 602 119 72 183 90 126 212 287 178 119 MIN 51 30 35 26 20 17 14 13 19 20 18 18 AC-FT 9600 4540 6400 2670 1530 2310 1290 1740 3210 2970 2910 2320 CFSM 10.3 5.02 6.84 2.85 1.81 2.47 1.43 1.87 3.55 3.18 3.12 2.57 IN. 11.85 5.60 7.89 3.29 1.89 2.85 1.60 2.15 3.96 3.66 3.59 2.87 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1972 - 1999, BY WATER YEAR (WY) MEAN 74.4 74.0 52.5 45.4 42.6 37.5 51.6 43.4 42.2 49.2 56.3 97.7 MAX 156 235 168 97.4 86.9 78.5 150 97.5 81.9 97.4 84.2 261 (WY) 1999 1993 1993 1993 1995 1972 1972 1992 1995 1993 1988 1996 MIN 16.6 23.9 18.8 12.9 10.8 11.5 13.6 4.12 20.0 12.8 20.2 26.3 (WY) 1992 1991 1992 1973 1992 1994 1995 1972 1994 1994 1993 1972 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1972 - 1999 ANNUAL TOTAL 27973.9 20917 ANNUAL MEAN 76.6 57.3 54.9 HIGHEST ANNUAL MEAN 84.0 1993 LOWEST ANNUAL MEAN 28.7 1994 HIGHEST DAILY MEAN 2140 Sep 22 721 Oct 22 4550 Sep 10 1996 LOWEST DAILY MEAN 5.6 May 13 13 May 2 1.2 Jun 28 1972 ANNUAL SEVEN-DAY MINIMUM 7.7 Jan 28 14 Apr 28 1.2 Jul 5 1972 INSTANTANEOUS PEAK FLOW 10500 Sep 10 1996 INSTANTANEOUS PEAK STAGE 22.11 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 55490 41490 39800 ANNUAL RUNOFF (CFSM) 5.04 3.77 3.61 ANNUAL RUNOFF (INCHES) 68.46 51.19 49.11 10 PERCENT EXCEEDS 193 112 121 50 PERCENT EXCEEDS 34 32 23 90 PERCENT EXCEEDS 9.8 17 9.9 e Estimated 191 RIO PUERTO NUEVO BASIN 50049100 RIO PIEDRAS AT HATO REY, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 1,000 20 30 40 50 70 100 200 300 400 500 700 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 192 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 mi2 (39.9 km2). PERIOD OF RECORD.--Water years 1971 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) DEC 15... 1430 37 407 7.7 28.5 1.4 6.4 82 <10 K160000 26000 MAR 04... 1230 21 461 7.9 26.8 17 6.3 77 <10 K1200 K1200 JUN 10... 1200 32 417 7.8 29.5 2.0 4.9 64 32 K130000 57000 SEP 20... 1100 21 404 7.9 29.5 27 6.3 82 13 39000 54000 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) DEC 15... 160 45 12 26 .9 3.3 160 <1.0 15 34 MAR 04... -- -- -- -- -- -- 162 -- -- -- JUN 10... 140 40 10 26 .9 3.2 139 <1.0 18 30 SEP 20... 140 40 10 25 .9 3.0 145 -- 13 29 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) DEC 15... .19 30 261 26.4 2 1.02 .180 1.20 1.10 .50 MAR 04... -- -- -- -- 19 .918 .082 1.00 1.10 -- JUN 10... .14 23 233 20.3 34 .870 .070 .940 1.10 -- SEP 20... .12 29 235 13.6 39 .820 .110 .930 .550 .37 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) DEC 15... 1.6 2.8 12 .190 <1 <100 20 <1 <1 <10 MAR 04... E1.4 -- -- E.170 -- -- -- -- -- -- JUN 10... E1.9 -- -- E.240 1 100 60 <1 <1 E12 SEP 20... .92 1.9 8.2 .170 -- -- -- -- -- -- 193 RIO PUERTO NUEVO BASIN 50049100 RIO PIEDRAS AT HATO REY, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) DEC 15... 270 <1 92 <.10 <1 <1 <10 <.010 <1 .26 MAR 04... -- -- -- -- -- -- -- -- -- -- JUN 10... 850 <1 70 <.10 1 <1 40 <.010 <4 .12 SEP 20... -- -- -- -- -- -- -- -- -- -- 194 RIO PUERTO NUEVO BASIN 50049820 LAGUNA SAN JOSE NO. 2 AT SAN JUAN, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°25'46", long 66°02'10", 0.2 mi (0.3 km) east of Caño de Martin Peña, and 650 ft (200 m) south of Isla Guachinango. DRAINAGE AREA.--Indeterminate. PERIOD OF RECORD.--Water years 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PH OXYGEN, COLI- SPE- WATER TRANS- DIS- FORM, STREP- CIFIC WHOLE PAR- SOLVED FECAL, TOCOCCI CON- FIELD TEMPER- ENCY OXYGEN, (PER- 0.45 FECAL, DUCT- (STAND- ATURE (SECCHI DIS- CENT UM-MF (COLS. DATE TIME ANCE ARD WATER DISK) SOLVED SATUR- (COLS./ PER (US/CM) UNITS) (DEG C) (IN) (MG/L) ATION) 100 ML) 100 ML) (00095) (00400) (00010) (00077) (00300) (00301) (31616) (31679) NOV 20... 1105 9280 8.6 28.5 28.0 5.4 69 2600 K30 MAR 15... 1030 17100 8.8 27.5 19.0 6.9 86 5300 710 JUN 11... 0940 24100 7.2 30.3 36.0 1.9 21 2200 91 ANC RESIDUE NITRO- WATER TOTAL NITRO- NITRO- NITRO- NITRO- GEN,AM- UNFLTRD AT 105 GEN, GEN, GEN, GEN, MONIA + PHOS- CARBON, FET DEG. C, NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC PHORUS ORGANIC FIELD SUS- TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL DATE MG/L AS PENDED (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L CACO3 (MG/L) AS N) AS N) AS N) AS N) AS N) AS P) AS C) (00410) (00530) (00615) (00630) (00610) (00605) (00625) (00665) (00680) NOV 20... 95 22 .010 <.020 .080 1.4 1.5 .160 9.3 MAR 15... 110 38 <.010 <.020 .030 -- E2.3 E.320 14 JUN 11... 95 19 <.010 <.020 .860 -- E2.1 E.190 14 195 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 1998 TO SEPTEMBER 1999 PH OXYGEN, COLI- ANC RESIDUE SPE- WATER TRANS- DIS- FORM, STREP- WATER TOTAL CIFIC WHOLE PAR- SOLVED FECAL, TOCOCCI UNFLTRD AT 105 CON- FIELD TEMPER- ENCY OXYGEN, (PER- 0.45 FECAL, 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 PENDED (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) NOV 20... 1240 28000 8.2 29.0 27.0 7.6 98 5400 610 130 21 MAR 15... 1200 54200 8.0 27.0 30.0 5.6 70 K13000 670 150 9 JUN 11... 1130 53300 7.7 29.6 18.0 2.2 24 >6000 K1500 120 27 NITRO- NITRO- NITRO- NITRO- NITRO- NITRO- GEN,AM- GEN, GEN, GEN, GEN, GEN, MONIA + NITRO- NITRO- PHOS- CARBON, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC GEN, GEN, PHORUS ORGANIC TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L AS N) AS N) AS N) AS N) AS N) AS N) AS N) AS NO3) AS P) AS C) (00620) (00615) (00630) (00610) (00605) (00625) (00600) (71887) (00665) (00680) NOV 20... .112 .038 .150 .500 1.1 1.6 1.8 7.7 .130 5.1 MAR 15... .061 .039 .100 1.40 -- E2.3 -- -- E.340 9.4 JUN 11... .140 .040 .180 .920 -- E1.3 -- -- E.190 5.2 196 THIS PAGE WAS LEFT BLANK INTENTIONALLY Río Río Río Río Río Río Río Río Río Río Río Río Río Grande Grande Gurabo Grande C a y a g u á s de de Cañas Lago Loíza Laguna San José Bahía de San Juan Laguna La Torrecilla Laguna de Piñones Quebrada de las Quebrada Quebradillas Quebrada Quebrada Quebrada Quebrada Arenas Bairoa Turabo Gurabo Turabo Caguitas Loíza Loíza Canóvanas Canóvanillas Maracuto P a st r a n a Blasina Caño de Martín Peña Valenciano 0509 059050 QUALITY-OF-WATER STATION AND NUMBER 0590 0503 222 EXPLANATION WELL AND WELL NUMBER LAKE-ELEVATION STATION AND NUMBER DRAINAGE BASIN BOUNDARY TOWN OR CITY SEDIMENT STATION AND NUMBER SURFACE-WATER STATION AND NUMBER Figure 18. Río Grande de Loíza basin. 197 CATAÑO SAN JUAN ATLANTIC OCEAN CAROLINA LOÍZA RÍO GRANDE HUMACAO SAN LORENZO LAS PIEDRAS TRUJILLO ALTO JUNCOS CAGUAS GURABO AGUAS BUENAS CANÓVANAS Basin area PUERTO RICO 0 0 1 1 2 2 3 3 4 4 5 MILES 5 KILOMETERS 0509 051310 051150 053025 051180 051800 0564 055750 0570 057025 0550 0618 059050 058350 0551 0554 055390 055225 055250 0575 0588 0591 0590 0503 222 1176 1179 1180 1181 50 1177 1178 198 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 mi2 (7.67 km2). PERIOD OF RECORD.--Water years 1973 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) DEC 16... 1145 12 529 7.1 26.4 10 3.2 40 <10 220000 66000 MAR 01... 1100 6.6 519 7.9 24.7 14 6.1 73 11 46000 23000 JUN 10... 1500 21 505 7.8 28.4 2.0 5.8 65 17 22000 28000 SEP 28... 1020 66 340 7.8 26.0 190 5.2 63 63 >600000 >1000000 ANC HARD- MAGNE- SODIUM POTAS- WATER CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, UNFLTRD SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) DEC 16... 190 58 10 29 .9 3.5 221 E1.0 13 39 MAR 01... -- -- -- -- -- -- 188 -- -- -- JUN 10... 180 56 10 30 1 3.0 175 <1.0 18 41 SEP 28... 110 36 5.7 17 .7 3.6 189 -- 10 22 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- RIDE, DIS- CONSTI- DIS- AT 105 GEN, GEN, GEN, GEN, GEN, DIS- SOLVED TUENTS, SOLVED DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC SOLVED (MG/L DIS- (TONS SUS- TOTAL TOTAL TOTAL TOTAL TOTAL DATE (MG/L AS SOLVED PER PENDED (MG/L (MG/L (MG/L (MG/L (MG/L AS F) SIO2) (MG/L) DAY) (MG/L) AS N) AS N) AS N) AS N) AS N) (00950) (00955) (70301) (70302) (00530) (00620) (00615) (00630) (00610) (00605) DEC 16... .11 26 311 10.1 <1 .750 .150 .900 3.30 .50 MAR 01... -- -- -- -- 15 1.18 .120 1.30 1.50 -- JUN 10... .14 26 289 16.4 5 1.04 .160 1.20 .440 -- SEP 28... <.10 16 224 40.0 358 .640 .090 .750 1.30 1.6 NITRO- CHRO- GEN,AM- BARIUM, BORON, CADMIUM MIUM, COPPER, MONIA + NITRO- NITRO- PHOS- TOTAL TOTAL WATER TOTAL TOTAL ORGANIC GEN, GEN, PHORUS ARSENIC RECOV- RECOV- UNFLTRD RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL TOTAL ERABLE ERABLE TOTAL ERABLE ERABLE DATE (MG/L (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS N) AS NO3) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) (00625) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) DEC 16... 3.8 4.7 21 .360 2 <100 30 <1 <1 <10 MAR 01... 1.3 2.6 12 .120 -- -- -- -- -- -- JUN 10... E.86 -- -- .150 1 100 60 <1 <1 E12 SEP 28... 2.9 3.6 16 .950 -- 70 -- -- -- -- 199 RIO GRANDE DE LOIZA BASIN 50050300 QUEBRADA BLASINA NEAR CAROLINA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 MANGA- METHY- IRON, LEAD, NESE, MERCURY SILVER, ZINC, LENE TOTAL TOTAL TOTAL TOTAL SELE- TOTAL TOTAL BLUE RECOV- RECOV- RECOV- RECOV- NIUM, RECOV- RECOV- CYANIDE ACTIVE ERABLE ERABLE ERABLE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS SUB- DATE (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) DEC 16... 700 1 410 <.10 <1 <1 10 <.010 4 .08 MAR 01... -- -- -- -- -- -- -- -- -- -- JUN 10... 290 <1 78 <.10 <1 <1 E20 <.010 <4 .22 SEP 28... -- -- -- -- -- -- -- -- -- -- 200 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 Río Emajagua and about 7.1 mi (11.4 km) southwest of San Lorenzo. DRAINAGE AREA.--6.00 mi2 (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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 38 27 178 42 21 e12 e11 e5.3 e5.3 6.6 11 9.0 2 39 25 66 33 19 e11 e21 e5.2 e5.2 169 10 9.2 3 47 24 274 36 19 e11 e32 e5.2 5.4 16 12 9.0 4 32 24 162 30 e18 e11 e16 e5.2 9.3 11 15 8.5 5 30 30 117 26 e18 e11 e12 e5.3 7.5 9.4 14 8.1 6 26 24 45 25 e17 e11 e11 e5.8 6.0 8.6 11 8.3 7 25 24 39 23 e17 e10 e10 e11 5.4 22 15 8.1 8 23 22 32 23 e16 e11 e9.8 e28 9.9 38 19 8.4 9 22 22 30 24 e16 e11 e9.7 e12 7.3 78 12 8.2 10 22 21 28 40 e16 e10 e9.0 e7.6 5.9 22 11 7.6 11 21 88 31 31 e16 e9.9 e8.6 e7.2 5.5 17 10 7.7 12 29 119 25 24 e24 e9.7 e8.3 e7.3 12 17 10 7.9 13 62 149 24 22 e18 e9.5 e7.9 e7.5 9.7 35 11 379 14 e42 67 26 38 e16 e9.4 e7.4 e6.7 8.1 96 9.8 222 15 26 32 22 196 e15 e9.4 e7.2 e6.3 6.0 34 11 37 16 20 25 25 106 e15 e9.4 e6.8 e6.1 8.8 21 10 20 17 19 64 27 41 e14 e9.3 e6.5 e5.9 191 76 9.5 33 18 18 25 22 34 e14 e9.1 e6.4 e5.8 22 28 9.1 113 19 59 22 e21 46 e14 e9.0 e6.3 e5.8 15 20 14 42 20 357 21 e22 38 e13 e8.9 e6.3 e8.5 29 19 11 21 21 58 20 e21 30 e13 e9.0 e6.4 e6.2 15 17 9.6 17 22 927 19 e20 27 e13 e8.9 e6.0 e6.3 11 15 110 15 23 167 19 e20 34 e13 e11 e6.5 e6.2 10 17 23 14 24 83 22 e21 30 e13 e37 e12 e7.0 8.7 14 31 17 25 48 19 e21 26 e13 e15 e6.9 e6.6 7.6 14 14 30 26 39 18 e20 25 e13 e14 e5.9 e5.8 7.0 13 12 18 27 67 17 e21 23 e12 e12 e5.7 e5.6 6.9 12 13 45 28 41 23 e62 23 e12 e12 e5.6 e5.5 6.6 12 11 149 29 33 21 e260 21 --- e12 e5.9 e5.5 6.4 11 12 31 30 31 18 117 21 --- e13 e5.5 e5.5 6.6 12 11 21 31 28 --- 47 20 --- e11 --- e5.4 --- 13 9.6 --- TOTAL 2479 1051 1846 1158 438 357.5 279.6 223.3 460.1 893.6 491.6 1324.0 MEAN 80.0 35.0 59.5 37.4 15.6 11.5 9.32 7.20 15.3 28.8 15.9 44.1 MAX 927 149 274 196 24 37 32 28 191 169 110 379 MIN 18 17 20 20 12 8.9 5.5 5.2 5.2 6.6 9.1 7.6 AC-FT 4920 2080 3660 2300 869 709 555 443 913 1770 975 2630 CFSM 13.3 5.84 9.92 6.23 2.61 1.92 1.55 1.20 2.56 4.80 2.64 7.36 IN. 15.37 6.52 11.45 7.18 2.72 2.22 1.73 1.38 2.85 5.54 3.05 8.21 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1978 - 1999, BY WATER YEAR (WY) MEAN 43.0 43.6 26.1 21.6 19.4 15.5 14.3 28.8 36.6 36.2 34.2 60.6 MAX 123 122 59.5 56.1 38.0 53.6 31.5 77.5 122 92.3 90.0 351 (WY) 1986 1988 1999 1992 1982 1998 1998 1985 1979 1993 1979 1998 MIN 13.1 8.34 6.65 8.16 6.36 5.07 4.64 7.20 11.3 12.5 9.30 11.8 (WY) 1990 1990 1990 1990 1979 1979 1979 1999 1985 1986 1991 1981 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1978 - 1999 ANNUAL TOTAL 24426.3 11001.7 ANNUAL MEAN 66.9 30.1 31.7 HIGHEST ANNUAL MEAN 62.7 1998 LOWEST ANNUAL MEAN 14.5 1990 HIGHEST DAILY MEAN 4690 Sep 22 927 Oct 22 4690 Sep 22 1998 LOWEST DAILY MEAN 8.7 Jul 1 5.2 May 2 3.1 May 7 1979 ANNUAL SEVEN-DAY MINIMUM 9.8 Jul 11 5.4 Apr 30 3.6 May 1 1979 INSTANTANEOUS PEAK FLOW 3690 Oct 22 45000 Sep 21 1998 INSTANTANEOUS PEAK STAGE 9.90 Oct 22 26.37 Sep 21 1998 INSTANTANEOUS LOW FLOW 2.8 May 5 1979 ANNUAL RUNOFF (AC-FT) 48450 21820 22950 ANNUAL RUNOFF (CFSM) 11.2 5.02 5.28 ANNUAL RUNOFF (INCHES) 151.44 68.21 71.73 10 PERCENT EXCEEDS 79 46 51 50 PERCENT EXCEEDS 21 16 15 90 PERCENT EXCEEDS 12 6.4 7.2 e Estimated 201 RIO GRANDE DE LOIZA BASIN 50050900 RIO GRANDE DE LOIZA AT QUEBRADA ARENAS, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 1,000 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 202 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR LOCATION.--Lat 18°09'40", long 65°58'58", Hydrologic Unit 2l0l0005, 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 mi2 (8.42 km2). 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 5.5 e7.1 34 18 6.5 3.4 e2.0 e1.3 e1.2 3.7 2.1 2.2 2 6.1 e7.8 64 17 5.4 3.4 e2.0 e1.3 e1.3 41 1.9 11 3 6.1 e5.0 71 18 5.2 3.3 e12 e1.3 e1.4 12 3.3 4.4 4 5.1 e4.7 36 13 5.0 3.2 e5.0 e1.4 e1.4 5.0 2.6 2.9 5 4.8 e4.4 20 11 4.8 e3.0 e2.8 e1.5 e2.3 3.5 4.7 2.4 6 4.7 e4.3 16 8.6 4.4 e2.9 e2.3 e1.4 e1.6 2.9 2.7 2.3 7 4.6 e4.6 14 7.1 4.2 e2.9 e2.0 e2.4 e1.5 3.2 13 2.2 8 4.6 e3.7 11 6.2 4.0 e2.9 e2.0 e25 1.6 5.9 4.9 2.6 9 4.5 e3.5 11 6.2 3.9 e2.8 e2.4 e9.3 1.9 4.8 2.7 2.4 10 4.4 e3.6 8.3 9.0 4.3 e2.8 e2.0 e2.8 2.5 2.9 2.2 2.1 11 4.2 28 10 14 3.8 e2.6 e2.7 e2.0 2.4 3.3 1.9 2.1 12 5.2 22 7.1 8.0 12 e2.5 e2.3 e1.7 4.3 7.1 1.8 1.9 13 4.3 46 5.9 6.0 6.5 e2.6 e1.9 e1.6 5.8 8.4 1.7 28 14 4.9 26 5.7 8.3 5.0 e2.5 e1.7 e2.2 2.5 44 1.6 24 15 4.3 16 4.5 33 4.3 e2.4 e1.7 e1.4 2.2 24 1.6 7.0 16 4.3 12 4.3 33 3.9 e2.5 e1.6 e1.3 11 15 1.6 4.3 17 4.5 12 5.0 24 3.6 e2.4 e1.6 e1.2 44 17 1.5 4.8 18 4.1 7.9 3.6 17 3.8 e2.3 e1.8 e1.2 14 11 1.5 12 19 9.2 6.3 3.3 15 3.8 e2.2 e1.8 e1.1 29 7.3 e2.7 36 20 29 8.6 3.7 13 3.6 e2.2 e1.7 e1.2 17 5.9 e2.3 17 21 25 6.4 3.1 11 3.5 e2.1 e1.6 e1.1 8.3 4.8 e2.0 8.3 22 94 5.1 2.8 9.7 3.6 e2.1 e1.5 e1.0 6.1 4.5 e14 4.7 23 23 8.7 2.6 8.7 3.6 e2.9 e1.7 e1.2 4.6 5.3 e8.9 3.5 24 8.5 12 2.4 8.2 3.5 e9.0 e2.2 e1.3 3.9 3.6 e13 3.2 25 7.5 5.4 2.9 7.4 3.5 e3.5 e1.9 e1.2 3.5 3.4 e5.3 3.5 26 e7.5 4.2 3.1 7.2 3.5 e6.8 e1.7 e1.1 3.2 2.7 e3.3 2.8 27 e24 4.1 6.1 6.5 3.6 e2.4 e1.8 e1.4 3.2 2.6 e3.1 5.5 28 e21 14 17 9.7 3.5 e2.4 e1.7 e1.2 3.3 2.3 e3.3 29 29 e13 6.6 43 6.2 --- e2.6 e1.6 e1.1 3.6 2.1 e2.5 9.2 30 e8.4 8.1 26 5.6 --- e2.3 e1.5 e1.2 3.2 2.6 e2.2 5.5 31 e6.1 --- 22 5.5 --- e2.1 --- e1.2 --- 2.8 e2.2 --- TOTAL 362.4 308.1 469.4 371.1 126.3 93.0 70.5 75.6 191.8 264.6 118.1 246.8 MEAN 11.7 10.3 15.1 12.0 4.51 3.00 2.35 2.44 6.39 8.54 3.81 8.23 MAX 94 46 71 33 12 9.0 12 25 44 44 14 36 MIN 4.1 3.5 2.4 5.5 3.5 2.1 1.5 1.0 1.2 2.1 1.5 1.9 AC-FT 719 611 931 736 251 184 140 150 380 525 234 490 CFSM 3.60 3.16 4.66 3.68 1.39 .92 .72 .75 1.97 2.63 1.17 2.53 IN. 4.15 3.53 5.37 4.25 1.45 1.06 .81 .87 2.20 3.03 1.35 2.82 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1984 - 1999, BY WATER YEAR (WY) MEAN 10.3 14.0 7.09 5.42 4.33 4.36 2.53 6.24 6.00 6.22 7.00 10.3 MAX 47.8 36.9 30.1 12.0 8.21 20.7 5.47 31.5 21.3 15.0 20.2 27.7 (WY) 1986 1985 1988 1999 1989 1989 1998 1985 1987 1993 1988 1996 MIN 2.75 2.49 1.49 1.74 1.32 1.64 .75 .62 2.12 2.02 1.95 1.36 (WY) 1993 1990 1990 1995 1985 1993 1994 1994 1994 1986 1994 1990 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1984 - 1999 ANNUAL TOTAL 3190.8 2697.7 ANNUAL MEAN 8.74 7.39 6.99 HIGHEST ANNUAL MEAN 12.3 1988 LOWEST ANNUAL MEAN 2.50 1990 HIGHEST DAILY MEAN 214 Sep 22 94 Oct 22 457 Dec 7 1987 LOWEST DAILY MEAN 1.3 Aug 5 1.0 May 22 .33 May 20 1994 ANNUAL SEVEN-DAY MINIMUM 1.4 Aug 1 1.1 May 17 .37 Apr 26 1994 INSTANTANEOUS PEAK FLOW 1080 Oct 22 7610 Sep 10 1996 INSTANTANEOUS PEAK STAGE 8.06 Oct 22 14.64 Sep 10 1996 INSTANTANEOUS LOW FLOW .30 May 21 1994 ANNUAL RUNOFF (AC-FT) 6330 5350 5060 ANNUAL RUNOFF (CFSM) 2.69 2.27 2.15 ANNUAL RUNOFF (INCHES) 36.52 30.88 29.22 10 PERCENT EXCEEDS 16 17 13 50 PERCENT EXCEEDS 3.9 3.9 2.8 90 PERCENT EXCEEDS 1.9 1.6 1.1 e Estimated 203 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 100 2 3 4 5 7 10 20 30 40 50 70 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 204 RIO GRANDE DE 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.-- 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 a local observer on a weekly basis. During high flow events sediment samples were collected with 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 years. EXTREMES FOR CURRENT YEAR 1999.-- SEDIMENT CONCENTRATION: Maximum daily mean, 742 mg/L October 22, 1998; Minimum daily mean, 1 mg/L severals days. SEDIMENT LOADS: Maximum daily mean, 465 tons (422 tonnes) October 22, 1998; Minimum daily mean, 0.01 ton <.01 tonne) . SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 5.5 3 .04 e7.1 e10 e.27 34 91 11 2 6.1 2 .04 e7.8 e13 e.46 64 229 50 3 6.1 2 .04 e5.0 e5 e.06 71 251 56 4 5.1 3 .04 e4.7 e4 e.05 36 100 11 5 4.8 4 .05 e4.4 e4 e.05 20 42 2.3 6 4.7 3 .04 e4.3 e5 e.06 16 28 1.3 7 4.6 3 .04 e4.6 e5 e.09 14 17 .63 8 4.6 6 .07 e3.7 e3 e.03 11 13 .38 9 4.5 10 .12 e3.5 e3 e.03 11 10 .30 10 4.4 8 .09 e3.6 e4 e.04 8.3 9 .21 11 4.2 6 .06 28 91 13 10 13 .39 12 5.2 5 .06 22 54 5.7 7.1 7 .14 13 4.3 8 .09 46 421 111 5.9 6 .09 14 4.9 13 .17 26 62 4.8 5.7 6 .10 15 4.3 10 .12 16 29 1.3 4.5 3 .04 16 4.3 7 .09 12 21 .71 4.3 2 .03 17 4.5 9 .11 12 21 .79 5.0 6 .08 18 4.1 9 .10 7.9 5 .12 3.6 2 .02 19 9.2 22 1.2 6.3 4 .07 3.3 2 .02 20 29 72 6.8 8.6 14 .43 3.7 3 .04 21 25 60 5.8 6.4 8 .14 3.1 1 .01 22 94 742 465 5.1 5 .07 2.8 1 .01 23 23 36 3.4 8.7 19 1.6 2.6 1 .01 24 8.5 8 .19 12 26 1.2 2.4 2 .01 25 7.5 6 .12 5.4 4 .06 2.9 3 .02 26 e7.5 e4 e.09 4.2 4 .05 3.1 3 .03 27 e24 e63 e9.7 4.1 4 .04 6.1 11 .24 28 e21 e53 e6.2 14 36 3.3 17 58 13 29 e13 e23 e.91 6.6 9 .16 43 170 31 30 e8.4 e6 e.14 8.1 14 .44 26 60 4.4 31 e6.1 e5 e.09 --- --- --- 22 47 2.7 TOTAL 362.4 --- 501.01 308.1 --- 146.12 469.4 --- 185.50 205 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 18 19 .98 6.5 5 .10 3.4 1 .01 2 17 31 1.5 5.4 3 .04 3.4 1 .01 3 18 34 1.7 5.2 1 .02 3.3 1 .01 4 13 7 .25 5.0 1 .01 3.2 1 .01 5 11 6 .16 4.8 1 .01 e3.0 e1 e.01 6 8.6 6 .13 4.4 1 .01 e2.9 e2 e.01 7 7.1 4 .08 4.2 1 .01 e2.9 e3 e.02 8 6.2 3 .06 4.0 1 .01 e2.9 e5 e.04 9 6.2 8 .15 3.9 1 .01 e2.8 e8 e.06 10 9.0 14 .42 4.3 3 .04 e2.8 e11 e.09 11 14 34 1.8 3.8 5 .05 e2.6 10 e.07 12 8.0 7 .17 12 28 2.3 e2.5 e9 e.06 13 6.0 1 .02 6.5 12 .21 e2.6 e8 e.05 14 8.3 5 .39 5.0 6 .09 e2.5 e7 e.05 15 33 70 11 4.3 3 .04 e2.4 e6 e.04 16 33 116 17 3.9 2 .02 e2.5 e8 e.05 17 24 31 2.1 3.6 1 .01 e2.4 e9 e.06 18 17 7 .33 3.8 1 .01 e2.3 e7 e.04 19 15 6 .23 3.8 1 .01 e2.2 e5 e.03 20 13 5 .19 3.6 2 .01 e2.2 e4 e.02 21 11 5 .16 3.5 2 .02 e2.1 e3 e.01 22 9.7 5 .13 3.6 3 .03 e2.1 e2 e.01 23 8.7 5 .11 3.6 4 .04 e2.9 e3 e.03 24 8.2 4 .10 3.5 5 .05 e9.0 e16 e.80 25 7.4 4 .08 3.5 6 .06 e3.5 e4 e.04 26 7.2 3 .05 3.5 7 .07 e6.8 e46 e1.3 27 6.5 2 .04 3.6 4 .04 e2.4 e3 e.02 28 9.7 10 .34 3.5 2 .02 e2.4 e3 e.02 29 6.2 1 .02 --- --- --- e2.6 e5 e.03 30 5.6 1 .01 --- --- --- e2.3 e3 e.02 31 5.5 1 .01 --- --- --- e2.1 e2 e.01 TOTAL 371.1 --- 39.71 126.3 --- 3.34 93.0 --- 3.03 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) APRIL MAY JUNE 1 e2.0 e2 e.01 e1.3 e1 e.01 e1.2 e1 e.01 2 e2.0 e1 e.01 e1.3 e1 e.01 e1.3 e1 e.01 3 e12 e30 e2.9 e1.3 e1 e.01 e1.4 e1 e.01 4 e5.0 e7 e.11 e1.4 e1 e.01 e1.4 e2 e.01 5 e2.8 e3 e.02 e1.5 e1 e.01 e2.3 e3 e.03 6 e2.3 e2 e.01 e1.4 e1 e.01 e1.6 e1 e.01 7 e2.0 e2 e.01 e2.4 e3 e.04 e1.5 e1 e.01 8 e2.0 e2 e.01 e25 e128 e44 1.6 2 .01 9 e2.4 e2 e.01 e9.3 e15 e.53 1.9 2 .01 10 e2.0 e2 e.01 e2.8 e1 e.01 2.5 3 .02 11 e2.7 e6 e.07 e2.0 e1 e.01 2.4 3 .02 12 e2.3 e8 e.05 e1.7 e1 e.01 4.3 10 .33 13 e1.9 e2 e.01 e1.6 e1 e.01 5.8 12 .24 14 e1.7 e1 e.01 e2.2 e1 e.01 2.5 1 .01 15 e1.7 e1 e.01 e1.4 e1 e.01 2.2 1 .01 16 e1.6 e1 e.01 e1.3 e1 e.01 11 24 1.7 17 e1.6 e1 e.01 e1.2 e1 e.01 44 134 19 18 e1.8 e1 e.01 e1.2 e1 e.01 14 29 1.2 19 e1.8 e1 e.01 e1.1 e1 e.01 29 46 4.3 20 e1.7 e1 e.01 e1.2 e1 e.01 17 36 1.8 21 e1.6 e1 e.01 e1.1 e1 e.01 8.3 11 .26 22 e1.5 e1 e.01 e1.0 e1 e.01 6.1 8 .14 23 e1.7 e1 e.01 e1.2 e2 e.01 4.6 5 .07 24 e2.2 e2 e.01 e1.3 e2 e.01 3.9 4 .05 25 e1.9 e2 e.01 e1.2 e1 e.01 3.5 3 .03 26 e1.7 e1 e.01 e1.1 e1 e.01 3.2 3 .03 27 e1.8 e1 e.01 e1.4 e1 e.01 3.2 3 .03 28 e1.7 e1 e.01 e1.2 e1 e.01 3.3 3 .03 29 e1.6 e1 e.01 e1.1 e1 e.01 3.6 3 .03 30 e1.5 e1 e.01 e1.2 e2 e.01 3.2 1 .01 31 --- --- --- e1.2 e2 e.01 --- --- --- TOTAL 70.5 --- 3.40 75.6 --- 44.85 191.8 --- 29.42 206 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 3.7 5 .05 2.1 3 .02 2.2 4 .02 2 41 402 130 1.9 2 .01 11 27 1.6 3 12 22 .80 3.3 5 .06 4.4 4 .06 4 5.0 4 .06 2.6 3 .02 2.9 2 .02 5 3.5 1 .01 4.7 10 .22 2.4 2 .01 6 2.9 1 .01 2.7 2 .02 2.3 2 .01 7 3.2 3 .03 13 38 2.6 2.2 2 .01 8 5.9 8 .21 4.9 8 .12 2.6 4 .03 9 4.8 4 .06 2.7 4 .03 2.4 3 .02 10 2.9 2 .02 2.2 2 .01 2.1 2 .01 11 3.3 4 .04 1.9 1 .01 2.1 2 .01 12 7.1 11 .23 1.8 1 .01 1.9 2 .01 13 8.4 13 .41 1.7 2 .01 28 57 7.1 14 44 145 25 1.6 2 .01 24 74 6.3 15 24 58 3.9 1.6 2 .01 7.0 10 .20 16 15 25 1.1 1.6 2 .01 4.3 4 .05 17 17 36 2.8 1.5 2 .01 4.8 5 .08 18 11 20 .64 1.5 3 .01 12 29 2.8 19 7.3 9 .19 e2.7 e4 e.03 36 226 109 20 5.9 8 .13 e2.3 e3 e.02 17 12 .69 21 4.8 3 .04 e2.0 e2 e.01 8.3 4 .08 22 4.5 3 .03 e14 e42 e5.0 4.7 2 .03 23 5.3 8 .14 e8.9 e10 e.28 3.5 2 .02 24 3.6 4 .04 e13 e53 e3.2 3.2 2 .02 25 3.4 4 .04 e5.3 e22 e.34 3.5 2 .02 26 2.7 2 .02 e3.3 e4 e.04 2.8 2 .01 27 2.6 3 .02 e3.1 e3 e.03 5.5 6 .15 28 2.3 4 .02 e3.3 e5 e.05 29 79 13 29 2.1 3 .02 e2.5 e3 e.02 9.2 16 .41 30 2.6 3 .02 e2.2 e2 e.01 5.5 7 .11 31 2.8 4 .03 e2.2 e3 e.02 --- --- --- TOTAL 264.6 --- 166.11 118.1 --- 12.24 246.8 --- 141.88 YEAR 2697.7 1276.61 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) NOV 13... 1030 68 226 41 96 DEC 30... 1115 28 153 12 91 APR 09... 1030 2.6 10 .07 100 SEP 13... 1015 47 50 6.3 92 207 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. SED. CHARGE, MENT, SUSP. SUSP. SUSP. INST. SEDI- DIS- FALL FALL FALL CUBIC MENT, CHARGE, DIAM. DIAM. DIAM. FEET SUS- SUS- % FINER % FINER % FINER DATE TIME PER PENDED PENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) JUL 02... 0915 226 13300 8130 20 25 32 SEP 19... 1430 285 3300 2540 41 51 64 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) JUL 02... 42 60 72 90 97 100 100 SEP 19... 78 85 91 98 100 100 100 208 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR LOCATION.--Lat 18°10'24", long 65°58'38", Hydrologic Unit 2l0l0005, on left downstream side of bridge on Highway 181, 0.2 mi (0.3 km) upstream from Río Grande de Loíza, and 1.5 mi (2.4 km) southwest of San Lorenzo. DRAINAGE AREA.--3.74 mi2 (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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e9.7 12 31 11 e3.3 2.7 2.0 1.2 1.1 1.0 1.4 13 2 e12 8.4 60 8.1 e3.1 2.6 2.0 1.1 1.1 128 1.3 25 3 e11 6.7 76 8.7 e3.0 2.6 18 1.1 .97 12 2.3 2.9 4 e8.7 6.0 46 6.8 e2.9 2.4 3.5 1.1 1.0 5.1 e1.5 1.4 5 e7.7 5.9 16 6.3 e3.0 2.3 2.7 1.1 1.5 3.0 2.1 1.3 6 e6.9 6.8 11 5.7 e2.6 2.3 2.4 1.0 .91 2.1 2.0 5.1 7 e6.3 7.8 8.4 5.3 e2.5 2.3 2.1 1.0 .86 1.8 3.1 2.0 8 e6.3 5.4 7.4 5.1 2.4 2.3 1.9 13 1.2 e26 2.4 1.4 9 e6.2 5.1 7.5 5.2 2.5 2.3 2.1 1.8 1.4 e12 1.7 1.2 10 e5.1 4.9 6.6 9.8 2.7 2.3 1.8 1.1 1.2 e3.9 1.5 1.2 11 e4.8 22 8.2 9.5 2.6 2.3 1.8 .96 1.1 e6.9 1.5 1.2 12 e6.1 33 6.4 6.8 12 2.3 1.8 .96 1.2 e44 1.2 1.1 13 e4.4 82 5.9 5.8 3.9 2.3 1.7 .91 1.8 5.9 1.3 15 14 e4.7 23 6.5 15 3.1 2.2 1.7 .89 1.0 37 1.3 15 15 e3.7 12 5.5 41 2.9 2.3 1.6 .88 .92 10 1.2 2.5 16 e4.6 9.4 5.4 38 2.8 2.2 1.5 .87 5.1 5.4 1.5 1.7 17 e3.9 9.2 5.7 9.5 2.6 2.2 1.5 .83 57 4.7 e1.3 2.0 18 e2.6 7.7 5.2 6.0 2.6 2.2 1.5 .84 3.8 3.6 e1.1 11 19 e7.5 7.0 5.0 5.5 2.7 2.2 1.5 .83 2.9 2.9 e3.1 70 20 14 7.1 5.0 4.7 2.7 2.2 1.5 1.0 2.8 2.5 e2.0 7.2 21 31 6.9 4.9 4.5 2.7 2.2 1.5 .90 1.7 2.2 e1.4 2.2 22 362 6.3 4.8 4.1 2.6 2.2 1.4 .83 1.5 e2.1 e76 1.6 23 27 7.2 4.9 3.9 2.6 2.5 1.4 .84 1.2 2.2 e88 1.3 24 4.7 7.4 4.7 3.8 2.6 5.1 1.4 .89 1.1 1.9 e94 1.3 25 2.8 5.7 5.0 3.6 2.6 2.6 1.3 .95 1.0 e2.1 e31 1.3 26 2.1 5.3 5.0 3.7 2.6 3.5 1.3 .84 .94 e1.8 e6.7 1.5 27 77 5.2 7.4 3.5 2.6 2.3 1.3 .83 .96 1.8 5.6 3.3 28 84 16 50 8.2 2.7 2.4 1.3 .88 .93 e1.6 7.5 74 29 36 5.7 76 3.5 --- 2.3 1.2 .89 .96 1.4 3.1 4.6 30 13 5.6 21 3.2 --- 2.2 1.2 .92 .96 1.6 2.0 2.5 31 9.4 --- 14 3.2 --- 2.1 --- .95 --- 1.6 1.9 --- TOTAL 785.2 352.7 526.4 259.0 86.9 75.9 67.9 42.19 100.11 338.1 352.0 274.8 MEAN 25.3 11.8 17.0 8.35 3.10 2.45 2.26 1.36 3.34 10.9 11.4 9.16 MAX 362 82 76 41 12 5.1 18 13 57 128 94 74 MIN 2.1 4.9 4.7 3.2 2.4 2.1 1.2 .83 .86 1.0 1.1 1.1 AC-FT 1560 700 1040 514 172 151 135 84 199 671 698 545 CFSM 6.77 3.14 4.54 2.23 .83 .65 .61 .36 .89 2.92 3.04 2.45 IN. 7.81 3.51 5.24 2.58 .86 .75 .68 .42 1.00 3.36 3.50 2.73 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1984 - 1999, BY WATER YEAR (WY) MEAN 10.4 11.5 5.68 5.26 3.60 3.61 2.36 5.64 6.01 5.78 6.63 17.5 MAX 36.2 33.4 22.8 23.4 10.3 17.4 6.60 35.8 17.5 20.5 14.5 76.5 (WY) 1986 1988 1988 1992 1984 1989 1985 1985 1996 1993 1996 1996 MIN 2.31 2.72 1.17 1.16 1.23 1.15 .66 .86 .92 1.45 1.51 1.88 (WY) 1987 1990 1990 1990 1990 1992 1995 1995 1997 1994 1994 1990 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1984 - 1999 ANNUAL TOTAL 4450.32 3261.20 ANNUAL MEAN 12.2 8.93 7.00 HIGHEST ANNUAL MEAN 12.4 1996 LOWEST ANNUAL MEAN 3.19 1990 HIGHEST DAILY MEAN 810 Sep 22 362 Oct 22 1750 Sep 10 1996 LOWEST DAILY MEAN .56 Aug 5 .83 May 17 .29 Sep 12 1990 ANNUAL SEVEN-DAY MINIMUM .59 Jul 31 .86 May 13 .41 May 19 1990 INSTANTANEOUS PEAK FLOW 2790 Oct 22 15000 Sep 10 1996 INSTANTANEOUS PEAK STAGE 12.04 Oct 22 20.87 Sep 10 1996 INSTANTANEOUS LOW FLOW .72 May 27 .26 May 30 1990 ANNUAL RUNOFF (AC-FT) 8830 6470 5070 ANNUAL RUNOFF (CFSM) 3.26 2.39 1.87 ANNUAL RUNOFF (INCHES) 44.27 32.44 25.43 10 PERCENT EXCEEDS 12 15 10 50 PERCENT EXCEEDS 2.1 2.7 2.0 90 PERCENT EXCEEDS 1.1 1.1 .94 e Estimated 209 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 0.1 1,000 0.2 0.5 1 2 5 10 20 50 100 200 500 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 210 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR--Continued WATER-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 1999.- SEDIMENT CONCENTRATION: Maximum daily mean, 1,840 mg/L October 22, 1998; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 3,570 tons (3,240 tonnes) October 22, 1998; Minimum daily mean, <0.01 ton (<0.01 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 e9.7 e9 e.24 12 34 2.7 31 124 22 2 e12 e18 e.62 8.4 26 .59 60 258 62 3 e11 e10 e.34 6.7 11 .20 76 423 372 4 e8.7 e2 e.04 6.0 4 .06 46 156 25 5 e7.7 e1 e.02 5.9 3 .05 16 28 1.3 6 e6.9 e2 e.03 6.8 35 .67 11 7 .21 7 e6.3 e2 e.04 7.8 37 .92 8.4 3 .07 8 e6.3 e4 e.06 5.4 16 .23 7.4 5 .10 9 e6.2 e5 e.09 5.1 15 .20 7.5 7 .15 10 e5.1 e5 e.06 4.9 7 .10 6.6 7 .12 11 e4.8 e5 e.06 22 107 24 8.2 27 .63 12 e6.1 e10 e.18 33 147 42 6.4 16 .29 13 e4.4 e6 e.07 82 595 418 5.9 15 .23 14 e4.7 e6 e.07 23 77 5.2 6.5 14 .25 15 e3.7 e5 e.05 12 36 1.2 5.5 7 .11 16 e4.6 e6 e.09 9.4 23 .58 5.4 6 .09 17 e3.9 e10 e.12 9.2 20 .51 5.7 3 .04 18 e2.6 e11 e.08 7.7 18 .37 5.2 1 .02 19 e7.5 e32 e2.4 7.0 12 .23 5.0 1 .01 20 14 50 3.5 7.1 8 .15 5.0 1 .01 21 31 178 84 6.9 6 .10 4.9 1 .01 22 362 1840 3570 6.3 4 .07 4.8 1 .01 23 27 63 9.3 7.2 9 .39 4.9 1 .01 24 4.7 8 .11 7.4 12 .30 4.7 1 .01 25 2.8 5 .04 5.7 6 .09 5.0 1 .01 26 2.1 4 .02 5.3 4 .05 5.0 1 .01 27 77 378 342 5.2 3 .04 7.4 15 .38 28 84 483 454 16 51 10 50 229 190 29 36 127 21 5.7 4 .05 76 251 133 30 13 21 .77 5.6 66 1.0 21 88 6.9 31 9.4 16 .41 --- --- --- 14 44 1.7 TOTAL 785.2 --- 4489.81 352.7 --- 510.05 526.4 --- 816.67 211 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 11 35 1.1 e3.3 e8 e.07 2.7 1 .01 2 8.1 26 .57 e3.1 e6 e.05 2.6 4 .03 3 8.7 20 .47 e3.0 e6 e.05 2.6 9 .06 4 6.8 15 .28 e2.9 e9 e.07 2.4 12 .08 5 6.3 14 .23 e3.0 e13 e.10 2.3 12 .08 6 5.7 11 .17 e2.6 e15 e.10 2.3 7 .04 7 5.3 5 .07 e2.5 e16 e.11 2.3 4 .02 8 5.1 2 .03 2.4 16 .10 2.3 2 .01 9 5.2 2 .03 2.5 8 .05 2.3 2 .01 10 9.8 25 1.5 2.7 4 .03 2.3 2 .01 11 9.5 29 .83 2.6 2 .01 2.3 4 .03 12 6.8 7 .13 12 68 17 2.3 7 .04 13 5.8 2 .03 3.9 9 .10 2.3 9 .05 14 15 59 21 3.1 7 .05 2.2 11 .06 15 41 202 64 2.9 5 .04 2.3 12 .07 16 38 149 60 2.8 4 .03 2.2 9 .05 17 9.5 27 .75 2.6 3 .02 2.2 7 .04 18 6.0 6 .10 2.6 4 .03 2.2 5 .03 19 5.5 3 .05 2.7 6 .05 2.2 3 .02 20 4.7 2 .03 2.7 8 .06 2.2 2 .01 21 4.5 2 .03 2.7 10 .08 2.2 1 .01 22 4.1 3 .03 2.6 11 .08 2.2 1 .01 23 3.9 3 .03 2.6 5 .03 2.5 2 .01 24 3.8 3 .03 2.6 2 .01 5.1 15 .44 25 3.6 3 .03 2.6 1 .01 2.6 6 .04 26 3.7 3 .03 2.6 1 .01 3.5 5 .05 27 3.5 3 .03 2.6 1 .01 2.3 4 .02 28 8.2 23 1.2 2.7 1 .01 2.4 3 .02 29 3.5 6 .05 --- --- --- 2.3 3 .02 30 3.2 6 .05 --- --- --- 2.2 2 .01 31 3.2 7 .06 --- --- --- 2.1 1 .01 TOTAL 259.0 --- 152.94 86.9 --- 18.36 75.9 --- 1.39 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) APRIL MAY JUNE 1 2.0 2 .01 1.2 1 <.01 1.1 3 .01 2 2.0 3 .02 1.1 2 <.01 1.1 5 .01 3 18 185 92 1.1 2 .01 .97 4 .01 4 3.5 10 .10 1.1 3 .01 1.0 4 .01 5 2.7 6 .05 1.1 4 .01 1.5 7 .03 6 2.4 5 .04 1.0 5 .01 .91 4 .01 7 2.1 5 .03 1.0 6 .02 .86 3 .01 8 1.9 4 .02 13 95 30 1.2 2 <.01 9 2.1 3 .02 1.8 4 .02 1.4 1 <.01 10 1.8 3 .01 1.1 2 .01 1.2 3 .01 11 1.8 3 .01 .96 1 <.01 1.1 6 .02 12 1.8 3 .01 .96 1 <.01 1.2 4 .01 13 1.7 2 .01 .91 1 <.01 1.8 3 .01 14 1.7 2 .01 .89 2 <.01 1.0 2 .01 15 1.6 2 .01 .88 2 <.01 .92 2 <.01 16 1.5 2 .01 .87 2 <.01 5.1 18 .92 17 1.5 3 .01 .83 2 <.01 57 302 109 18 1.5 3 .01 .84 3 .01 3.8 21 .26 19 1.5 3 .01 .83 4 .01 2.9 12 .10 20 1.5 3 .01 1.0 3 .01 2.8 8 .06 21 1.5 3 .01 .90 2 <.01 1.7 6 .03 22 1.4 2 .01 .83 2 <.01 1.5 4 .02 23 1.4 2 .01 .84 3 .01 1.2 3 .01 24 1.4 2 .01 .89 3 .01 1.1 2 .01 25 1.3 2 .01 .95 2 .01 1.0 2 <.01 26 1.3 3 .01 .84 2 <.01 .94 2 <.01 27 1.3 3 .01 .83 1 <.01 .96 1 <.01 28 1.3 3 .01 .88 1 <.01 .93 1 <.01 29 1.2 2 .01 .89 1 <.01 .96 1 <.01 30 1.2 1 <.01 .92 1 <.01 .96 1 <.01 31 --- --- --- .95 1 <.01 --- --- --- TOTAL 67.9 --- 92.49 42.19 --- 30.15 100.11 --- 110.56 212 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 1.0 1 <.01 1.4 3 .01 13 51 13 2 128 1090 1420 1.3 3 .01 25 113 32 3 12 35 1.3 2.3 6 .05 2.9 18 .19 4 5.1 14 .19 e1.5 3 .01 1.4 3 .01 5 3.0 8 .07 2.1 2 .01 1.3 3 .01 6 2.1 3 .02 2.0 2 .01 5.1 20 1.6 7 1.8 1 <.01 3.1 1 .01 2.0 17 .09 8 e26 e97 e20 2.4 1 .01 1.4 12 .05 9 e12 e6 e.31 1.7 1 <.01 1.2 5 .02 10 e3.9 e1 e.01 1.5 1 <.01 1.2 2 .01 11 e6.9 e19 e.55 1.5 1 <.01 1.2 2 .01 12 e44 e176 e31 1.2 3 .01 1.1 2 .01 13 5.9 14 .32 1.3 7 .02 15 27 2.0 14 37 184 48 1.3 7 .02 15 48 5.1 15 10 30 .94 1.2 6 .02 2.5 4 .03 16 5.4 8 .12 1.5 5 .02 1.7 4 .02 17 4.7 3 .04 e1.3 e2 e.01 2.0 5 .03 18 3.6 2 .02 e1.1 e1 e<.01 11 48 7.2 19 2.9 1 .01 e3.1 e7 e.10 70 412 302 20 2.5 1 .01 e2.0 e1 e.01 7.2 38 1.2 21 2.2 2 .01 e1.4 e1 e.01 2.2 5 .03 22 e2.1 e1 e.01 e76 e565 e482 1.6 1 <.01 23 2.2 1 .01 e88 e332 e105 1.3 2 .01 24 1.9 1 <.01 e94 e550 e333 1.3 3 .01 25 e2.1 e1 e.01 e31 e117 e14 1.3 2 .01 26 e1.8 e1 e.01 e6.7 e17 e.34 1.5 1 .01 27 1.8 2 .01 5.6 10 .29 3.3 5 .11 28 e1.6 e4 e.02 7.5 33 1.9 74 207 95 29 1.4 4 .01 3.1 5 .04 4.6 5 .07 30 1.6 4 .01 2.0 1 .01 2.5 1 .01 31 1.6 3 .01 1.9 1 <.01 --- --- --- TOTAL 338.1 --- 1523.02 352.0 --- 936.92 274.8 --- 459.84 YEAR 3261.20 9142.20 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) OCT 22... 2000 861 1980 4610 72 NOV 13... 1030 72 134 26 94 13... 1111 409 3240 3580 86 JAN 15... 1000 20 107 5.8 76 JUL 02... 0908 564 16600 25300 25 05... 0900 E3.2 9 -- 21 SEP 13... 1000 59 54 8.6 99 19... 1520 337 1700 1550 97 213 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. SED. CHARGE, MENT, SUSP. SUSP. SUSP. INST. SEDI- DIS- FALL FALL FALL CUBIC MENT, CHARGE, DIAM. DIAM. DIAM. FEET SUS- SUS- % FINER % FINER % FINER DATE TIME PER PENDED PENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) OCT 22... 0830 532 10400 14900 39 52 68 DEC 28... 2133 537 1790 2600 52 64 77 SEP 19... 1421 381 4160 4280 38 49 64 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) OCT 22... 82 92 95 98 99 100 100 DEC 28... 86 89 92 98 100 100 100 SEP 19... 78 85 88 93 96 97 99 214 RIO GRANDE DE LOIZA BASIN 50051310 RIO CAYAGUAS AT CERRO GORDO, PR LOCATION.--Lat 18°09'13", long 65°57'24", 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 mi2 (26.4 km2). 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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 58 e62 288 e51 43 26 23 13 15 71 20 19 2 48 e58 129 e53 39 26 28 12 11 483 15 18 3 59 e54 147 e78 41 25 68 14 11 84 31 17 4 44 e52 408 e54 34 26 48 12 40 33 24 17 5 42 e54 e225 e52 41 21 24 12 23 28 25 17 6 e40 e54 e142 e49 36 23 20 13 13 19 19 22 7 39 e53 e138 e46 33 21 17 51 12 49 63 23 8 36 47 e82 e46 e32 22 17 144 152 98 22 42 9 34 46 e70 e46 e31 19 18 67 59 66 17 25 10 35 46 e50 e54 e30 17 17 25 26 31 13 22 11 30 343 e81 e58 28 17 16 19 15 21 16 45 12 60 166 e58 e48 59 19 18 17 37 30 15 30 13 38 441 e54 47 41 19 16 14 76 75 16 423 14 78 172 e78 e52 33 17 15 14 22 358 16 471 15 41 79 e43 e300 34 18 14 11 23 139 27 105 16 31 57 e38 214 32 18 14 11 68 67 24 53 17 39 109 e81 89 31 19 13 9.4 353 152 17 69 18 38 49 e42 64 32 20 15 9.6 175 90 14 212 19 92 45 e50 52 27 18 16 8.4 241 48 29 265 20 381 52 e57 54 31 16 16 14 74 46 34 104 21 143 59 e51 50 23 17 16 9.7 38 45 20 49 22 1920 50 e61 47 29 18 20 9.1 26 35 352 37 23 225 78 e65 64 23 22 30 14 25 45 266 30 24 75 68 e53 73 23 214 36 15 13 28 249 32 25 65 49 e77 53 28 54 21 16 10 28 103 47 26 e60 43 e40 61 25 44 15 13 11 17 49 40 27 e106 39 e38 43 25 28 15 10 12 20 39 58 28 e109 54 e128 51 24 34 17 12 11 27 47 250 29 e86 54 e377 41 --- 27 16 12 14 23 33 54 30 e70 48 e122 38 --- 38 16 12 12 17 24 28 31 e63 --- e52 41 --- 30 --- 11 --- 21 20 --- TOTAL 4185 2581 3325 2069 908 933 635 624.2 1618 2294 1659 2624 MEAN 135 86.0 107 66.7 32.4 30.1 21.2 20.1 53.9 74.0 53.5 87.5 MAX 1920 441 408 300 59 214 68 144 353 483 352 471 MIN 30 39 38 38 23 16 13 8.4 10 17 13 17 AC-FT 8300 5120 6600 4100 1800 1850 1260 1240 3210 4550 3290 5200 CFSM 13.2 8.43 10.5 6.54 3.18 2.95 2.08 1.97 5.29 7.25 5.25 8.58 IN. 15.26 9.41 12.13 7.55 3.31 3.40 2.32 2.28 5.90 8.37 6.05 9.57 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1977 - 1999, BY WATER YEAR (WY) MEAN 65.6 69.1 47.1 34.8 30.9 24.5 21.0 41.9 45.0 44.9 52.0 81.4 MAX 176 196 163 99.5 74.1 64.1 46.0 155 140 118 202 330 (WY) 1986 1988 1988 1998 1997 1998 1985 1985 1979 1979 1979 1998 MIN 14.4 19.2 12.5 14.6 11.0 11.3 10.7 9.68 10.9 15.4 14.5 16.9 (WY) 1992 1982 1992 1990 1992 1992 1980 1990 1994 1994 1991 1980 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1977 - 1999 ANNUAL TOTAL 34231 23455.2 ANNUAL MEAN 93.8 64.3 46.5 HIGHEST ANNUAL MEAN 89.7 1979 LOWEST ANNUAL MEAN 18.6 1990 HIGHEST DAILY MEAN 4100 Sep 22 1920 Oct 22 5120 Sep 10 1996 LOWEST DAILY MEAN 14 Jul 1 8.4 May 19 7.1 Feb 4 1981 ANNUAL SEVEN-DAY MINIMUM 16 Jul 11 10 May 16 8.5 Jun 19 1994 INSTANTANEOUS PEAK FLOW 11200 Oct 22 13200 Aug 31 1979 INSTANTANEOUS PEAK STAGE 22.24 Oct 22 9.44 Aug 31 1979 ANNUAL RUNOFF (AC-FT) 67900 46520 33710 ANNUAL RUNOFF (CFSM) 9.19 6.30 4.56 ANNUAL RUNOFF (INCHES) 124.84 85.54 61.99 10 PERCENT EXCEEDS 134 128 72 50 PERCENT EXCEEDS 39 38 25 90 PERCENT EXCEEDS 21 14 13 e Estimated 215 RIO GRANDE DE LOIZA BASIN 50051310 RIO CAYAGUAS AT CERRO GORDO, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 1 10,000 2 5 10 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 216 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 Colón García and 2.0 mi (3.2 km) northwest from Escuela Segunda Unidad de Carlos Zayas. DRAINAGE AREA.--25.0 mi2 (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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 231 225 478 211 104 56 38 27 19 49 46 47 2 226 212 459 180 103 56 43 29 19 456 45 60 3 235 199 498 188 98 53 113 28 20 90 56 47 4 213 191 674 168 97 53 62 29 30 59 56 44 5 206 195 382 160 96 51 44 29 34 50 61 42 6 198 196 272 150 92 e50 39 25 24 45 54 42 7 192 193 276 143 91 e50 38 41 21 58 91 41 8 186 177 210 140 88 50 36 192 34 88 72 42 9 189 173 201 142 87 51 38 80 41 118 53 40 10 184 169 184 171 90 49 36 47 29 74 47 37 11 178 461 193 177 85 48 36 39 24 60 45 42 12 191 405 171 145 119 46 35 40 34 69 44 37 13 193 738 167 138 102 46 34 38 52 90 43 401 14 e203 396 169 153 85 49 33 35 29 309 41 333 15 174 256 158 433 80 48 32 32 25 129 45 92 16 170 211 156 316 78 49 31 30 48 93 46 69 17 175 260 171 184 74 47 31 28 375 135 42 86 18 156 191 152 151 73 45 31 27 103 98 40 192 19 214 180 147 148 72 46 31 27 122 76 55 291 20 614 183 152 139 70 46 30 31 78 70 52 101 21 326 184 145 132 69 47 31 29 60 67 44 76 22 2630 170 139 124 67 47 30 26 47 63 164 67 23 740 182 138 125 65 50 32 27 45 68 123 62 24 389 205 145 127 63 111 38 26 39 60 131 63 25 293 167 145 118 62 61 37 27 35 59 79 74 26 249 158 135 120 61 60 29 24 34 53 58 68 27 385 157 145 113 59 45 29 22 33 52 55 82 28 395 210 408 118 59 43 30 21 31 48 57 261 29 325 166 620 107 --- 45 30 20 32 48 56 105 30 253 165 319 103 --- 45 29 20 32 49 49 83 31 233 --- 231 101 --- 40 --- 19 --- 52 47 --- TOTAL 10546 6975 7840 4925 2289 1583 1126 1115 1549 2835 1897 3027 MEAN 340 232 253 159 81.8 51.1 37.5 36.0 51.6 91.5 61.2 101 MAX 2630 738 674 433 119 111 113 192 375 456 164 401 MIN 156 157 135 101 59 40 29 19 19 45 40 37 AC-FT 20920 13830 15550 9770 4540 3140 2230 2210 3070 5620 3760 6000 CFSM 13.6 9.30 10.1 6.35 3.27 2.04 1.50 1.44 2.07 3.66 2.45 4.04 IN. 15.69 10.38 11.67 7.33 3.41 2.36 1.68 1.66 2.30 4.22 2.82 4.50 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1990 - 1999, BY WATER YEAR (WY) MEAN 160 140 104 115 82.0 60.8 43.3 61.6 104 95.8 107 217 MAX 340 232 253 192 160 158 104 186 290 208 196 631 (WY) 1999 1999 1999 1992 1998 1998 1998 1992 1992 1993 1996 1996 MIN 77.6 69.2 59.2 50.1 21.0 17.4 16.8 25.2 42.3 42.3 39.3 59.7 (WY) 1993 1996 1998 1995 1992 1992 1992 1995 1994 1994 1994 1990 SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1990 - 1999 ANNUAL TOTAL 67315 45707 ANNUAL MEAN 184 125 110 HIGHEST ANNUAL MEAN 154 1996 LOWEST ANNUAL MEAN 67.8 1994 HIGHEST DAILY MEAN 5020 Sep 22 2630 Oct 22 10000 Sep 10 1996 LOWEST DAILY MEAN 31 Aug 4 19 May 31 6.3 Apr 29 1992 ANNUAL SEVEN-DAY MINIMUM 36 Jul 30 20 May 28 7.4 Apr 25 1992 INSTANTANEOUS PEAK FLOW 9990 Oct 22 56800 Sep 10 1996 INSTANTANEOUS PEAK STAGE 18.48 Oct 22 35.62 Sep 10 1996 ANNUAL RUNOFF (AC-FT) 133500 90660 79870 ANNUAL RUNOFF (CFSM) 7.38 5.01 4.41 ANNUAL RUNOFF (INCHES) 100.16 68.01 59.92 10 PERCENT EXCEEDS 325 241 188 50 PERCENT EXCEEDS 99 70 64 90 PERCENT EXCEEDS 48 30 26 e Estimated 217 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued O N D J F M A M J J A S 1998 1999 WATER YEAR 10 10,000 20 50 100 200 500 1,000 2,000 5,000 DAILY MEAN DISCHARGE, IN CUBIC FEET PER SECOND 218 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, 3,080 mg/L November 10, 1997; 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 1999-- SEDIMENT CONCENTRATION: Maximum daily mean, 2,380 mg/L October 22, 1998; Minimum daily mean, 20 mg/L July 5, 1999. SEDIMENT LOADS: Maximum daily mean, 27,200 tons (24,700 tonnes) October 22, 1998; Minimum daily mean, tons 2 (1.8 tonnes) May 31, 1999. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 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 NOVEMBER DECEMBER 1 231 48 30 225 51 31 478 541 1200 2 226 48 29 212 42 24 459 739 950 3 235 50 32 199 51 27 498 812 1740 4 213 51 29 191 62 32 674 824 1620 5 206 51 29 195 67 35 382 542 576 6 198 44 24 196 68 36 272 297 220 7 192 37 19 193 56 29 276 155 118 8 186 30 15 177 46 22 210 117 66 9 189 24 12 173 44 21 201 94 51 10 184 29 14 169 74 34 184 85 42 11 178 36 17 461 655 984 193 81 42 12 191 46 24 405 613 874 171 89 41 13 193 138 84 738 1080 2820 167 99 45 14 e203 e126 e68 396 173 187 169 96 44 15 174 110 52 256 126 88 158 48 20 16 170 119 55 211 94 53 156 26 11 17 175 95 45 260 300 229 171 35 16 18 156 72 31 191 182 94 152 48 20 19 214 162 179 180 139 68 147 44 18 20 614 1080 2100 183 113 56 152 39 16 21 326 736 726 184 91 45 145 37 15 22 2630 2380 27200 170 73 34 139 50 19 23 740 338 822 182 150 82 138 66 25 24 389 153 161 205 220 132 145 74 29 25 293 106 84 167 90 41 145 81 32 26 249 75 51 158 75 32 135 76 28 27 385 356 581 157 66 28 145 70 28 28 395 330 436 210 208 152 408 686 4030 29 325 461 412 166 94 42 620 790 1900 30 253 108 75 165 59 26 319 442 391 31 233 66 42 --- --- --- 231 341 212 TOTAL 10546 --- 33478 6975 --- 6358 7840 --- 13565 219 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 1998 TO SEPTEMBER 1999 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 FEBRUARY MARCH 1 211 274 157 104 84 24 56 105 16 2 180 228 111 103 88 24 56 147 22 3 188 190 97 98 89 23 53 199 29 4 168 158 72 97 74 20 53 222 32 5 160 132 57 96 60 16 51 223 31 6 150 110 44 92 47 12 e50 e153 e21 7 143 99 38 91 36 8.9 e50 e102 e14 8 140 96 36 88 32 7.6 50 77 10 9 142 93 36 87 45 10 51 96 13 10 171 91 42 90 59 14 49 120 16 11 177 88 42 85 63 14 48 130 17 12 145 86 34 119 134 55 46 126 16 13 138 83 31 102 131 37 46 88 11 14 153 104 60 85 50 12 49 59 7.9 15 433 738 1430 80 24 5.2 48 49 6.4 16 316 493 572 78 30 6.2 49 82 11 17 184 282 142 74 41 8.1 47 117 15 18 151 289 118 73 58 11 45 88 11 19 148 310 124 72 72 14 46 65 8.1 20 139 280 105 70 60 11 46 55 6.8 21 132 176 63 69 49 9.1 47 48 6.1 22 124 85 28 67 48 8.6 47 47 5.9 23 125 60 20 65 83 15 50 73 10 24 127 65 22 63 134 23 111 175 74 25 118 74 23 62 145 24 61 115 19 26 120 99 32 61 145 24 60 184 31 27 113 125 38 59 127 20 45 72 8.7 28 118 120 38 59 109 18 43 56 6.6 29 107 111 32 --- --- --- 45 60 7.1 30 103 100 28 --- --- --- 45 132 16 31 101 91 25 --- --- --- 40 86 9.4 TOTAL 4925 --- 3697 2289 --- 474.7 1583 --- 508.0 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) APRIL MAY JUNE 1 38 51 5.3 27 91 6.7 19 62 3.2 2 43 49 6.1 29 88 6.9 19 93 4.7 3 113 157 73 28 95 7.2 20 101 5.5 4 62 112 19 29 146 11 30 105 8.6 5 44 85 10 29 177 14 34 100 9.1 6 39 107 11 25 93 6.4 24 94 6.0 7 38 130 13 41 73 15 21 97 5.4 8 36 118 12 192 245 269 34 142 14 9 38 110 11 80 143 33 41 197 21 10 36 124 12 47 63 8.0 29 202 16 11 36 142 14 39 72 7.6 24 191 13 12 35 159 15 40 91 9.9 34 149 13 13 34 165 15 38 122 13 52 113 16 14 33 175 15 35 138 13 29 88 6.9 15 32 203 17 32 89 7.6 25 74 4.9 16 31 215 18 30 54 4.4 48 85 13 17 31 162 13 28 39 3.0 375 490 637 18 31 119 9.8 27 55 4.0 103 118 42 19 31 100 8.4 27 81 6.0 122 182 72 20 30 143 12 31 119 10 78 88 19 21 31 202 17 29 153 12 60 50 8.1 22 30 238 19 26 119 8.3 47 44 5.6 23 32 247 21 27 89 6.4 45 44 5.4 24 38 158 16 26 79 5.5 39 63 6.7 25 37 94 9.5 27 126 9.3 35 85 7.9 26 29 69 5.4 24 184 12 34 89 8.1 27 29 105 8.1 22 187 11 33 92 8.1 28 30 147 12 21 163 9.4 31 93 7.9 29 30 119 9.5 20 96 5.2 32 88 7.6 30 29 95 7.4 20 55 3.0 32 82 7.2 31 --- --- --- 19 39 2.0 --- --- --- TOTAL 1126 --- 434.5 1115 --- 539.8 1549 --- 1002.9 220 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 1998 TO SEPTEMBER 1999 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) JULY AUGUST SEPTEMBER 1 49 74 9.8 46 67 8.2 47 79 10 2 456 1010 3100 45 70 8.4 60 129 21 3 90 120 32 56 74 11 47 172 22 4 59 31 4.9 56 78 12 44 102 12 5 50 20 2.7 61 82 13 42 55 6.2 6 45 30 3.6 54 86 12 42 35 4.0 7 58 70 14 91 147 47 41 48 5.3 8 88 96 31 72 84 17 42 72 8.2 9 118 162 65 53 32 4.5 40 107 12 10 74 110 23 47 35 4.4 37 144 15 11 60 63 10 45 43 5.2 42 133 15 12 69 53 9.8 44 52 6.2 37 118 12 13 90 111 39 43 61 7.1 401 527 834 14 309 475 533 41 61 6.8 333 475 606 15 129 169 60 45 61 7.4 92 37 9.6 16 93 85 22 46 63 7.8 69 35 6.4 17 135 150 84 42 82 9.2 86 95 31 18 98 145 39 40 107 11 192 294 346 19 76 69 14 55 141 21 291 463 574 20 70 52 9.7 52 164 23 101 117 33 21 67 45 8.2 44 116 14 76 104 21 22 63 47 7.9 164 245 262 67 106 19 23 68 48 8.8 123 129 49 62 95 16 24 60 41 6.6 131 169 78 63 79 13 25 59 33 5.3 79 124 27 74 48 9.5 26 53 30 4.3 58 137 22 68 28 5.2 27 52 41 5.7 55 151 22 82 17 3.7 28 48 53 6.9 57 97 15 261 405 399 29 48 57 7.4 56 58 8.8 105 133 39 30 49 60 7.9 49 41 5.4 83 53 12 31 52 63 8.9 47 54 6.9 --- --- --- TOTAL 2835 --- 4184.4 1897 --- 752.3 3027 --- 3120.1 YEAR 45707 68114.7 e Estimated WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- % FINER DATE TIME PER PENDED PENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) OCT 23... 0900 718 230 446 81 NOV 13... 1150 1960 3590 19000 64 DEC 30... 1030 307 359 298 91 MAR 03... 0800 52 198 28 94 JUL 02... 1140 1870 2140 10800 76 221 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- SEDI- SED. SED. SED. CHARGE, MENT, SUSP. SUSP. SUSP. INST. SEDI- DIS- FALL FALL FALL CUBIC MENT, CHARGE, DIAM. DIAM. DIAM. FEET SUS- SUS- % FINER % FINER % FINER DATE TIME PER PENDED PENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) DEC 28... 2300 1690 4200 19200 40 49 63 JUL 02... 1040 1660 5640 25200 24 29 35 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) DEC 28... 73 76 81 93 99 100 100 JUL 02... 45 52 62 85 99 100 100 222 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 Borinquén, 8.1 mi (13.0 km) upstream from Río Grande de Loíza. DRAINAGE AREA.--7.14 mi2 (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 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 32 37 59 e32 21 14 11 8.5 6.1 13 9.4 16 2 31 32 88 e28 20 14 16 8.2 6.2 71 9.0 14 3 32 29 95 31 19 13 21 8.5 5.6 23 9.9 11 4 29 28 126 26 19 13 14 8.5 6.3 16 11 9.4 5 28 29 77 27 18 13 13 8.1 6.2 15 11 9.2 6 26 27 58 26 18 13 12 7.7 6.3 14 9.6 9.0 7 25 26 50 25 18 13 12 11 5.5 18 21 9.0 8 24 24 41 25 17 13 12 32 10 22 13 8.3 9 22 23 38 27 16 13 15 12 9.5 37 10 8.3 10 22 25 31 36 17 13 13 8.9 8.2 20 9.3 8.4 11 21 36 34 33 16 12 13 8.5 7.4 17 9.0 9.3 12 22 45 28 31 29 12 12 8.4 10 21 8.7 8.7 13 22 89 26 30 19 12 12 7.8 12 34 8.5 207 14 26 52 26 34 17 12 12 7.5 9.1 77 8.2 70 15 21 38 25 86 16 12 11 7.0 9.2 36 8.4 22 16 21 33 24 63 16 12 11 6.5 14 23 8.4 15 17 20 37 24 44 15 12 11 6.3 127 25 8.1 13 18 19 30 22 38 15 11 11 6.3 28 21 8.0 48 19 39 27 22 35 15 11 11 6.2 30 18 9.9 69 20 88 28 22 34 15 11 10 6.3 24 16 9.5 26 21 51 27 21 30 14 11 10 6.2 18 15 8.7 17 22 262 25 20 28 15 11 10 6.2 16 14 75 14 23 67 24 20 26 15 12 10 6.1 15 15 18 13 24 28 25 20 25 15 16 10 6.5 14 16 17 13 25 22 23 21 24 15 12 9.9 6.4 13 16 11 13 26 21 22 20 23 15 13 9.7 5.9 12 e11 10 14 27 71 23 21 22 14 12 9.2 6.0 12 e10 11 15 28 52 26 e97 27 14 12 9.2 5.8 12 10 11 30 29 35 26 e88 21 --- 13 8.9 5.5 12 10 11 25 30 30 30 e47 20 --- 12 8.8 5.7 12 11 9.2 16 31 28 --- e34 20 --- 12 --- 5.4 --- 10 8.6 --- TOTAL 1237 946 1325 977 473 385 348.7 249.9 476.6 675 390.4 760.6 MEAN 39.9 31.5 42.7 31.5 16.9 12.4 11.6 8.06 15.9 21.8 12.6 25.4 MAX 262 89 126 86 29 16 21 32 127 77 75 207 MIN 19 22 20 20 14 11 8.8 5.4 5.5 10 8.0 8.3 MED 28 28 28 28 16 12 11 6.5 12 16 9.6 14 AC-FT 2450 1880 2630 1940 938 764 692 496 945 1340 774 1510 CFSM 5.59 4.42 5.99 4.41 2.37 1.74 1.63 1.13 2.23 3.05 1.76 3.55 IN. 6.44 4.93 6.90 5.09 2.46 2.01 1.82 1.30 2.48 3.52 2.03 3.96 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1990 - 1999, BY WATER YEAR (WY) MEAN 28.7 24.1 19.8 23.9 17.6 13.5 10.2 14.4 24.5 22.4 21.8 47.9 MAX 51.3 37.9 42.7