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rn~p~~ ,-- C)A Halliburton C - - "--" - FIELD INVESTIGATION TEAM ACTIVITIES AT UNCONTROLLED HAZARDOUS SUBSTANCES FACILITIES - ZONE I NUS CORPORATION SUPERFUND DIVISION ·r U I U U l , :-:C: ,_ h *64411* 64411 .. FINAL DRAFT PRELIMINARY ASSESSMENT TUTU ESSO ST. THOMAS, U.S. VIRGIN ISLANDS PREPARED UNDER TECHNICAL DIRECTIVE DOCUMENT NO. 02-8902-43 CONTRACT NO. 68-01-7346 I, FOR THE ENVIRONMENTAL SERVICES DlVISION U.S. ENVIRONMENTAL PROTECTION AGENCY MARCH 24, 1989 NUS CORPORATION SUPERFUND DIVISION 02-8902-43-PA REV. NO. 1 SUBMITTED BY: r - {,,let,~::. /J ___, t,L \... ~·-t < DIANE TRUBE PROJECT MANAGER REVIEWED/APPROVED BY: ~.VY}~n ROAlDM.NAMAN~ FIT OFFICE MANAGER ,,.; J . ' :, \ / 02-8902-43-PA qev ;'Jo 1 POTENTIAL HAZARDOUS WASTE SITE PRELIMINARY ASSESSMENT PART I: SITE INFORMATION 1. Site Name/Alias Tutu Esso 2. Street Route 384 (Tutu District) City St. Thomas County_N_A ___________ _ 3 EPA ID No._.,;,,.N~e""-w"-S=i...:..te~-------- 4. Latitude 18° 20' 25" N State U.S.Virgin Islands Zip0~8~0~0_2 __ _ County Code_N.;;.;.A....;,.__ __ Cong. Dist. NA Longitude 64° 53' 18" W USGS Quad. Eastern St. Thomas, U.S. Virgin Islands 5. Owner Esso VI Inc. Street GPO Box 4269 City San Juan 6. Operator Danill Bayard Street P 0. Box 7441 City St. Thomas 7. Type of Ownership ~ Private D County O Federal O Municipal 8. Owner/Operator Notification on File 0 RCRA 3001 ~ None 9. Permit Information Date ---- □ Unknown Tel. No.(809) 792-2920 State Puerto Rico Zip 00936 Tel. No. 809-775-2360 State U.S Virgin Islands Zip 00801 O State D Unknown □Other __ _ 0 CERCLA 103c Date ------ Permit Permit No. Date Issued Expiration Date Comments None 10. Site Status ~ Active D Inactive O Unknown 11. Vea rs of Operation 1969 to Present I U T () U l ,: : ,.! 1 t3 02-8902-43-PA Rev. No. 1 12. Identify the types of waste units (e.g., landfill, surface impoundment, piles, stained soil, above- or below-ground tanks or containers, land treatment, etc.) on site. Initiate as many waste unit numbers as needed to identify all waste sources on site. (a) Waste Management Areas Waste Unit No. Waste Unit Type Underground Storage Tanks (b) Other Areas of Concern Facility Name for Unit Waste Oil Underground Storage Tanks Identify any miscellaneous spills, dumping, etc. on site; describe the materials and identify their locations on site. No miscellaneous spills, incidents of dumping, etc. were observed on the site during the NUS Corp. Region 2 FIT on-srte reconnaissance. It should be noted, however, that an underground gasoline tank has been suspected of leaking on s,te. 13. Information available from Contact Amy Brochu Preparer Joseph Mayo Agency U 5. EPA Tel. No. (201) 906-6802 Agency NUS Corp. Region 2 FIT Date~3/ ___ 2_4 ..... /8~9 ___ _ IU! {_j().J. ~'.:.::'. ..L c; '.)2-8902-43-PA Rev. No. 1 PART II: WASTE SOURCE INFORMATION For each of the waste units identified in Part I, complete the following six items. Waste Unit Underground Storage Tanks, Waste Oil Underground Storage Tanks 1. Identify the RCRA status and permit history, if applicable, and the age of the waste unit. There is no known RCRA permit for the underground storage tanks for waste oil The manager indicated that the tanks were installed in 1969. 2. Describe the location of the waste unit and identify clearly on the site map. The waste units are located underground below a tire rack inside the garage 3. Identify the size or quantity of the waste unit (e.g., area or volume of a landfill or surface impoundment, number and capacity of drums or tanks). Specify the quantity of hazardous substances in the waste unit. 4. 5. The volume of the storage tanks is unknown. Identify the physical state(s) of the waste type(s) as disposed of in the waste unit. The physical state(s) should be categorized as follows: solid, powder or fines, sludge, slurry, liquid, or gas. The physical state of the waste oil 1n the tanks is liquid Identify specific hazardous substance(s) known or suspected to be present in the waste unit. The waste units contain waste oil from automotive repair and servicing act1v1t1es. The manager 1nd1cated that only waste oil was put in the tanks. Solvents and cleaners are not disposed of 1n the tanks. Tank sampling, conducted by Cenref Labs and Belgodere and Associates Inc, indicates the presence of toluene, ethylbenzene, and xylene in wastes stored there. 6. Describe the containment of the waste unit as it relates to contaminant migration via groundwater, surface water, and air. The waste is contained 1n underground storage tanks There 1s no information that indicates that the tanks are leaking; therefore, there is little potential for contaminant migration to air, groundwater, or surface water. The manager indicated that the tanks are periodically emptied by ESSO Corp and the waste is shipped off St. Thomas for disposal. Ref. Nos. 1 18 19 20 21 22 11 .. n OUJ. PART Ill: HAZARD ASSESSMENT GROUNDWATER ROUTE 02-8902-43-PA r{ev No. 1 1. Describe the likelihood of a release of contaminant(s) to the groundwater as follows: observed, alleged, potential, or none. Identify the contaminant(s) detected or suspected, and provide a rationale for attributing the contaminant(s) to the facility. There is a potential for contaminants to be released from the waste oil storage tanks to groundwater. The manager of the facility indicated that only waste oil was stored in the tanks. Cleaners and solvents are not put into the tanks. Small quantities of contaminants may have been introduced into the oil in the normal course of ,ts use as motor 011. Tank s.impling ' indicates the presence of toluene, ethylbenzene, and xylene ,n wastes stored on site in the tanks; however, these results are questionable due to chain-of-custody problems. A soil gas vapor study also confirmed chlorinated hydrocarbons on site. Ref. Nos. 1, 21, 22 2. Describe the aquifer of concern; include information such as depth, thickness, geologic composition, permeability, overlying strata, confining layers, interconnections, discontinuities, depth to water table, groundwater flow direction. The rock units of St. Thomas and St. John are divided into three ma1or groups: the Water Island Formation, the Virgin Island Group, and an unnamed group of diont1c plutons The Water Island Formation, which is late lower Cretaceous in age, consists of keratophyre and spillates. The Virgin Island Group, which is probably early Cretaceous or Alb,an ,n age, consists of andesitic-pyroclastic rocks and sedimentary formations. The Virgin Island Group is divided into four formations: the LouisenhoJ Formation, which consists of aug1te-andesite brecc1a, tuff, and conglomerate; the Outer Brass Limestone, vv.hich consists of partially silicified- tuffaceous-radiolarian-l1mestone; the Tutu Formation, which consists of tuffaceous wacke, including megabreccia near the base and limestone near the top; and the Hans Lollik Formation, which may be Eocene ,n age and consists of aug1te-andesite breccia and tuff. The final group Is made up of one or more diontic plutons. These unnamed dikes and plugs of quartz-andesine-hornblende porphyry are Upper Cretaceous and Lower Tertiary In age. Alluvian deposits are quarternary in age The Water Island Formation, which consists of 95 percent volcanic flow breccias. was probably extruded on a relatively level ocean floor T'le absence of terrrgenous sediments from this formation indicates that there were no emergent islands present ,n the area at the t1 me of extrusion. Emergent islands would have served as a source of weather sediments or detritus, which are not present in this formation. There Is evidence that sea floor subsidence occurred during the greater part of the accumulation of this formation. However, ~he subsidence was not rap,d enough to maintain a constant water level, thereby causing explosive eruptions near the top of the formation. Regional uplift occurred near the end of the Water Island time. The Louisenhoj Formation of the Virgin Island Group unconformably overlies the Water Island Formation and crops out on about half of the land area on St. Thomas. Pillsbury Sound between St. Thomas and St. John was the origin of this formation. Evidence of this center is based upon the coarseness of volcanic ejecta in the formation in nearby eastern St Thomas and western St. John. Material is less coarse and tuffs are more predominant as one moves further east and west away from the center or origin. This augite-andesite formation ranges in thickness from 4,000 to 13,000 feet In certain areas of St. Thomas and St. John conglomerates are interbedded with andes1tic rocks at the base of this formation. The depositional environment of this conglomerate varies from location to location throughout this formation. The Outer Brass Formation of the Virgin Island Group is mostly siliceous limestone which overlies the Louisenhoj Formation This limestone formation is an offshore deposit formed by radiolanan and foraminiferal remains including a minor amount of tuff. Thicknesses are known to be at least 600 feet 02-8902-43-PA qev No. 1 Overlying the Outer Brass Formation 1s the Tutu Formation. The Tutu Formation is fine- to coarse-grained volcanic wackes, which are termed flysch This formation is derived from eroding sediments from the Lou1senhoJ andes1tes. Exposed thicknesses are known to be as much as 6000 feet. Within this formation are a megabrecc1a l1thofacies with an average thickness of 30 feet and a limestone member with a thickness up to 300 feet. The Hans Lollik Formation, which consists of at least 10,000 feet of aug1te-andesite pyroclastic rocks, crops out on Little Hans Lollik Island. Diorit1c plutons are located in Pillsbury Sound between St. Thomas and St. John; in the narrows, between St. John and the British Virgin Islands; and south of St. Thomas. The exact delineation of these plutons is uncertain. Throughout the islands isolated dikes of quartz-andesine porphyries. andesine-hornblende porphyries, lamprophyres, breccias, and pegmatites appear. • Folding occurred after the deposition of the Virgin Island Group. Rocks were tilted to form a northward-dipping homocline, which is cut by sets of faults trending N 45°W, N 55°E, and north. Well-defined joint sets parallel each of the maier fault trends. Dips range from 15° to 90° with the average being 40°. Strike-slip faults have horizontal offsets of less than 1 mile. Two major strike-slip graben structures or fault systems exist. The first passes through Redhook, St. Thomas and the eastern tip of Lovango Cay. The second crosses St. John, from Contact Point on the southwest to Brown's Bay on the northeast. \/lost recent Pleistocene to Holocene alluvial deposits occurred or1mar1ly 1n coastal emoayments. However, a narrow bank of alluvium extends up to Turpentine Run on the east end of the island. Most of these deposits are composed of slit, clay, and thin, d1scont1nuous beds of sand and gravel Maximum thickness of these Is 50 feet. Groundwater movement Is limited to openings and 10Ints along fault zones. Regional geologic information is 1nsuffic1ent to determine whether these fractures and fault zones are present in all of the above formations; however, for this report It is assumed that the fractures and fault zones are present in all of the formations. The valleys on the island are the result of weak zones caused by faulting and jointing and are primary recharge areas for groundwater Alluvial deposits have a high porosity but low permeability, making this aquifer unfavorable for groundwater production In coastal embankments throughout the island, saltwater intrusion Is widespread 1n alluvial deposits. In most areas, alluvial deposits are interconnected with bedrock and act to recharge precipitation to the underlying bedrock The direction of groundwater flow 1n the Turpentine Run Basin Aquifer ,s south-southeast which Is generally along the direction of flow of Turpentine Run Depth to groundwater 1n the aquifer ranges from 5 to 60 feet, and the altitude of the water levels ranges from 1 to 209 feet above mean sea level Ref Nos. 8, 10, 14 3. Is a designated sole source aquifer within 3 miles of the site? No sole source aquifer, as designated in the Federal Register, is located within 3 miles of the site. Ref. No. 7 4. What is the depth from the lowest point of waste disposal/storage to the highest seasonal level of the saturated zone of the aquifer of concern? The lowest point of the waste oil storage tank is unknown. It is assumed that the bottom of the tank is at least 6 feet below the ground surface. Depth to groundwater in Four Winds Shopping Plaza Well Nos. 1 and 2 is 13 feet and 9 feet, respectively. The Four Winds Shopping Plaza wells are located approximately 400 feet from the Tutu Esso facility. The depth from the lowest point of waste storage (6 feet) to the highest seasonal level of the saturated zone (9 feet) is 3 feet Ref. Nos 1, 2, 8 02-8902-43-PA =\ev No. i 5. What is the permeability value of the least permeable continuous intervening stratum between the ground surface and the aquifer of concern? There are no continuous intervening strata between the ground surface and the bedrock aquifer. Soils are generally thin in the area around the site. The water-bearing formations In the Turpentine Run Basin Aquifer are composed primarily of fractured and jointed volcanic rocks. The range of hydraulic conductivities associated with these formations Is 10j to 10' cm/sec. Ref. Nos. 9, 10, 14 ' 6. What is the net precipitation for the area? Net precipitation is usually calculated by subtracting mean annual lake evaporation (a surrogate measure for evapotranspiration) from normal annual total prec1p1tation. Mean annual lake evaporation information was not available for St. Thomas; however, evapotranspiratron data were available. These data indicate that 95.8 percent of the incident precrp1tation on St. Thomas is lost through evapotranspiration. The normal annual total precipitation for St. Thomas 1s 43.74 inches, but because of orographic effects on the Island, normal annual total precipitation can range from 35 inches to 50 inches over short distances. :n the Turpentine Run Basin, normal annual precIpItatIon Is 40 inches. Calculations for net precIp1tatIon are provided below: 40 inches prec1pitat1on x 95.8 percent lost to evapotranspirat1on = 38.32 inches lost to evapotranspI ration 40 inches precipitation - 38.32 inches lost to evapotranspirat1on = 1 68 inches net prec1p1tation. Ref. Nos. 3, 5, 11, 12 7. Identify uses of groundwater within 3 miles of the site (i.e., private drinking source, municipal source, commercial, industrial, irrigation, unusable). Groundwater within 3 miles of the site is used as a source of private and municipal drinking water. and for commercial purposes There are at least 41 wells w1th1n 2 miles of the site. Thirty-six of these wells are within 1 mile of the site. Sixteen of these wells have been ordered closed because of contamination with volatile organic compounds. Ref. Nos. 6, 8 8. What is the distance to and depth of the nearest well that is currently used for drinking or irrigation purposes? Distance ..;..1..;..10-=-0.;:.....;..fe-=-e-=-t;;__ _____ _ Depth Unknown The nearest well that Is used for domestic purposes is the Francois Laplace well. It is uncertain whether this well is used for drinking. A number of wells in the vicinity of the Francois well have been closed because of contamination with volatile organic compounds. Ref. Nos. 6, 8 9. Identify the population served by the aquifer of concern within a 3-mile radius of the site. It is difficult to estimate the population served by groundwater on St. Thomas, as there are few records available on groundwater withdrawal, sale, and transport. The locations of some wells in St. Thomas are unknown, and there are reports of illegal drilling on the island. It is estimated that there are 500 to 600 private wells on St. Thomas. Most of these are used for nondrinking domestic uses such as washing and flushing, although some may be used for drinking. There are a number of wells that are used for commercial purposes. Water from these wells 1s trucked to private houses and pumped ,nto cisterns to augment 1 \J 1 1,u l collected from roofs. Groundwater 1s also bottled and sold in supermarkets ' 02-8902-43-PA Rev No. 1 There are at least 41 wells in the Turpentine Run Basin. Recently 16 of these wells have been ordered closed because they were found to be contaminated with volatile organic compounds. One of these wells was a major supplier of water to the eastern end of the island. Estimates of the population using groundwater as a source of drinking water range from none to approximately 11,000--the population of the Turpentine Run Basin which is not served by water from the desalinization plant. The actual population served by groundwater is probably less than 11,000, as desalinated water and water from wells outside the 3-mile radius is trucked into the area. Ref. Nos. 8, 12, 13, 16, 17 SURFACE WATER ROUTE 10. Describe the likelihood of a release of contaminant(s) to surface water as follows: observed. alleged, potential, or none. Identify the contaminant(s) detected or suspected, and provide a rationale for attributing the contaminants to the facility. No potential exists for wastes to the released to surface water. Waste o,I is stored in an underground storage tank. The tank is located under the garage, and no incidents of leaks or so1lls have been reported. Ref No. 1 11. Identify and locate the nearest downslope surface water. If possible, include a description of possible surface drainage patterns from the site. Not applicable. Containment of the waste unit precludes any release to surface water Ref. No. 1 12. What is the facility slope in percent? (Facility slope is measured from the highest point of deposited hazardous waste to the most downhill point of the waste area or to where contamination is detected.) Not applicable Containment of the waste unit precludes any release to surface water Ref No. 1 13. What is the slope of the intervening terrain in percent? (Intervening terrain slope is measured from the most downhill point of the waste area to the probable point of entry to surface water.) Not applicable. Containment of the waste unit precludes any release to surface water Ref. No. 1 14. What is the 1-year 24-hour rainfall? Not applicable Containment of the waste unit precludes any release to surface water. Ref No. 1 15. What is the distance to the nearest downslope surface water? Measure the distance along a course that runoff can be expected to follow. Not applicable Containment of the waste unit precludes any release to surface water Ref. No 1 !UT •:)() .. 02-8902-43-PA Rev. No 1 16. Identify uses of surface waters within 3 miles downstream of the site (i.e., drinking, irrigation, recreation, commercial, industrial, not used). Not applicable. Containment of the waste unit precludes any release to surface water. Ref. No. 1 17. Describe any wetlands, greater than 5 acres in area, within 2 miles downstream of the site. Include whether it is a freshwater or coastal wetland. Not applicable. Containment of the waste unit precludes any release to surface water. : Ref. No. 1 18. Describe any critical habitats of federally listed endangered species within 2 miles of the site along the migration path. Not applicable. Containment of the waste unit precludes any release to surface water Ref. No. 1 19. What is the distance to the nearest sens1t1ve environment along or contiguous to the migration path (if any exist within 2 miles)? Not applicable. Containment of the waste unit precludes any release to surface water. Ref. No. 1 20. Identify the population served or acres of food crops irrigated by surface water intakes within 3 miles downstream of the site and the distance to the intake(s). Not applicable. Containment of the waste unit precludes any release to surface water. Ref No. 1 21. What is the state water qua I ity classification of the water body of concern? Not applicable Containment of the waste unit precludes any release to surface water Ref. No. 1 22. Describe any apparent biota contamination that is attributable to the site. Not applicable. Containment of the waste unit precludes any release to surface water Ref. No. 1 AIR ROUTE 23. Describe the likelihood of a release of contaminant(s) to the air as follows: observed, alleged, potential, none. Identify the contaminant(s) detected or suspected, and provide a rationale for attributing the contaminant(s) to the facility. There is a potential for contaminants to be released to the air. Waste oil is contained in underground storage tanks. There are no reports of any spills, and the wastes are not known to contain volatile compounds, however, volatile compounds have been detected in soil gas vapor screening surveys Ref Nos 1, 22 I > I I '·' I ' .. ·,,._} j 24. What is the population within a 4-mile radius of the site? 02-8902-43-PA ~ev No 1 Based on the 1980 census, the population within 4 miles of the site is approximately 36,000. Ref. No. 15 FIRE ANO EXPLOSION ~ 25. Describe the potential for a fire or explosion to occur with respect to the haz:ardous substance(s) known or suspected to be present on site. Identify the hazardous substance(s) and the method of storage or containment associated with each. Wastes on site are stored in an underground storage tank; however, due to their volatile nature, there is a potential for fire or explosion conditions present on the site. Ref. Nos.1, 22 26. What is the population within a 2-mile radius of the hazardous substance(s) at the facility? 3ased on the 1980 census, the population within 2 miles of the site 1s approximately 19,000 Ref. No. 15 DIRECT CONTACT/ON-SITE EXPOSURE 27. Describe the potential for direct contact with hazardous substance(s) stored in any of the - waste units on site or deposited in on-site soils. Identify the hazardous substance(s) and the accessibility of the waste unit. There is no potential for direct contact with hazardous substances. The waste 1s stored in an underground storage tank under a garage. The area of the storage tank 1s accessible only to workers. ~ef No. 1 28. How many residents live on a property whose boundaries encompass any part of an area contaminated by the site? There is no evidence that any residential areas have been contaminated by the site. Ref. No. 1 29. What is the population within a 1-mile radius of the site? Based on 1980 census data, the population within 1 mile of the site is approximately 11,000. Ref. No. 15 ru 1 ,_),); ,:... ,:· c .. PART IV: SITE SUMMARY AND RECOMMENDATIONS 02-8902-43-PA .~ev. No. 1 Tutu Esso is an automotive service station located in the Tutu area of St. Thomas, U.S. Virgin Islands. The primary activities at the site are gasoline sales and automotive repair and maintenance. The area within approximately 1 mile of the site is densely populated and contains some commercial properties. The Four Winds Plaza shopping center is located just west of the site There are large housing developments northwest, north, and east of the site. Beyond 1 mite, there are s<.>attered \ . smaller villages and towns. The densely populated and highly commercial town of Charlotte Amalie is located approximately 2.5 miles west of the site. On February 15, 1989, NUS Corp. Region 2 FIT conducted an on-site reconnaissance of the Tutu Esso Site. The station manager indicated that all waste oil from the station operations was stored in two underground tanks located under a tire rack 1n the garage. The tanks have been in use since about 1969 and contain only automotive waste oil which 1s periodically removed by Esso Corp and disposed of off St. Thomas. The volume of the tank 1s unknown, and there are no known permits for the tanks. The waste oil at the Tutu Esso station is contained in underground tanks. There is no evidence that the tanks are unsound or that there were any spills or releas-es to the en· , ronment The tanks reportedly hold only waste oil which is disposed of by Esso Corporation. Based on the waste containment, there is no potential for contamination of surface water or air, and there 1s no potential for fire and explosion or exposure by direct contact. There is a small potential for groundwater contamination if the tanks are unsound; however, there is no evidence of this On the bam of the above information, a recommendation of MEDIUM PRIORITY is provided There were no known enforcement actions taken aga,nst Tutu Essa in the past. However, the owners of the Tutu Esso Site have been identified as one of nine potentially responsible parties in the contamination of groundwater in the Tutu area. In July and August of 1987, EPA confirmed by sampling that volatile organic compounds were present in a number of wells in the Tutu area. One of the wells was a major source of commercially provided potable water for the eastern end of the island. Additional sampling of wastes on site indicated the presence of toluene, ethylbenzene, and xylene; however, these results are suspect due to problems with regard to chain-of-custody integrity. Soil gas vapor sampling indicates the presence of chlorinated hydrocarbons. EPA removal action activities ,n the Tutu area included sampling of wells and cisterns, removal of contaminated water from cisterns, cleaning of cisterns, and supplying of clean water on a regular basis to affected residents. Additional sampling procedures are recommended to ascertain the extent, if any, of contamination associated with this site. I:.! i ATTACHMENT A MAPS ANO PHOTOS * No photos were taken as the waste unit was below ground. ; ii; TUTU ESSO ST. THOMAS, U.S. VIRGIN ISLANDS CONTENTS Figure 1: Site Location Map 02-8902-43-PA Rev No. 0 ·r LJ i (}i.J J ,::. •- .,: .. -., und !'!\ •••• /' ✓ /11 SITE LOCATION MAP TUTU ESSO SERVICE STATION ST. THOMAS, U.S. VIRGIN ISLANDS SCALE: 1"• 2000" 02-8902-43-PA Rev. No. O FIGURE 1 ATTACHMENT B REFERENCES REFERENCES 02-8902-43-PA Rev. No. 1 1. Field Notebook No. 0398, U.S. Virgin Islands Drum Reconnaissance, TDD No. 02-8902-29, NUS Corp. Region 2 FIT, Edison, New Jersey, February 14 to 17, 1989. 2. U.S. Department of the Interior, Geological Survey Topographic Maps, 7.5 minute series, "Central St. Thomas, Virgin Islands and Eastern St. Thomas, Virgin Islands Quadrangle" 1955, \ revised 1982. • 3. Gomez-Gomez, F. and J.E. Heisel. Summary Appraisals of the Nation's Groundwater Resources-Caribbean Region. Geological Survey Professional Paper 813-4, 1980. 4. Stone, R.G. Scientific Survey of Porto Rico and the Virgin Islands, Volume XIX - Part 1, Meteorology of the Virgin Islands. 1942. 5. Climate of Puerto Rico and Virgin Islands, Climatography of the United States No. 60, June 1982. 6. Tutu Well Site Potable Water Alternatives Report, Anna's Retreat, St. Thomas, U S. Virgin Islands. Prepared for U.S. EPA Region 2 By Region 2 Technical Assistance Team, Western/SPER Division, December 1989. 7 Telecon Note: Conversation between Nancy Schlater, EPA, and Diane Trube, NUS Corp., Re: Sole source aquifer in VI. March 3, 1989. 8. Graves, R.P. and R. Gonzalez. Potentiometric surface of the Turpentine Run Basin Aquifer 1n the Tutu Area, Eastern St. Thomas, U.S. Virgin Islands, September 11, 1987. US Geological Survey Water Resource Investigations Report 88-4131, 1988. 9 Uncontrolled hazardous waste site ranking system, A user's manual, 40 CFR, Part 300, Appendix A, 1986. 10 Donnelly, T W, Geology of St. Thomas and St. John, U 5. Virgin Islands, In Caribbean Geological lnvest1gat1ons, Geological Society of America, Memoir 98. ed H. H. Hess, 1966. 11. Climatological Data Annual Summary, Puerto Rico and Virgin Islands. National Oceanic and Atmospheric Adm1nistrat1on, 1987 12. Torres-Sierra, H. and R. Dacosta, Estimated Water Use in St. Thomas, US Virgin Islands, July 1983 to June 1984. Caribbean Research Institute, Technical Report No. 21. 13. Memo to Stephen D Luhig, EPA, from Carlos O'Neill, EPA. Authorization of CERCLA Removal Action Monies for the Tutu Well Site. January 6, 1988. 14. Jordan, D.G. and O.J. Cosner, A Survey of the Water Resources of St. Thomas, Virgin Islands, U.S. Geological Survey Open File Report, 1973. 15. Water Management Plan for the Public Water System, Prepared for the Government of the Virgin Islands by CH2M HILL. July 1983. l i...l. i i. __ . ,_.) J. REFERENCES (cont'd) 02-8902-43-PA R.ev. No. 1 16. Telecon Note: Conversation between Fernando Gomez, USGS, and Rich Feinberg, NUS Corp. on 3/11/89 at 1045 hours. Re: Hydrology and groundwater use in St. Thomas. 17. Telecon Note: Conversation between 0. Goetz of Polycaribe and D. Trube, NUS Corp., on \. 3/14/89 at 1430 hours. Re: Wells and water use on St. Thomas. 18. Tel econ Note: Conversation between L. Reed, DPNR, and D. Trube, NUS Corp. on 3/3/89 at 1640 hours. Re: Permits for site on St. Thomas. 19. Telecon Note: Conversation between T. Gutshall, Tutu Esso Manager, and J. Mayo, NUS Corp., on 3/15/89 1510 hours. RE: Background information for Tutu Esso. 20. Record of Communication, telephone conversation between Leonard Re1d,DPNR, and A. Brochu, U.S EPA Region 2, Jan. 30, 1989, 1400 hours. 21 Tutu Well field Area Sample Analysis Data Summary, Tutu Esso Service Station, St Thomas, U.S. Virgin Islands. Prepared for US. EPA Region 2 by Cenref Labs, COM, Federal Programs Corporation, March 6, 1989. 22. Esso Tutu Service Station Soil Gas Vapor Screening Survey Report, St. Thomas, U S. Virgin Islands. Prepared for Esso Standard Oil S.A. LTD, by Belgodere and Associates Inc., August 1988 REFERENCE NO. l I NUS CORPORATION II 0398 ' . 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REFERENCE NO. 2 und ~2 \ .• SITE LOCATION MAP TUTU ESSO SERVICE STATION ST. THOMAS, U.S. VIRGIN ISLANDS SCALE: 1·• 2000' lee ~te. f \' I • ---• :-.. ~ \.~110 . ~::::: FIGURE 1 REFERENCE NO. 3 Summary Appraisals of the Nation's Ground-Water Resources- Caribbean Region , , By FERNANDO GOMEZ-GOMEZ and JAMES E. HEISEL GEOLOGICAL SURVEY PROFESSIONAL PAPER 813-U UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON:1980 ,: ,. i-'> ---- - 02-8902-43-PA Rell. No. 0 O11erlying the Outer Brass Formation is the Tutu Formation. The Tutu Formation is fine- to coarse-grained volcanic wackes, which are termed flysch. This formation is deri11ed from eroding sediments from the Louisenhoj andesites. Exposed thicknesses are known to be as much as 6000 feet. Within this formation is a megabreccia lithofacies with an a11erage thickness of 30 feet and a limestone member with a thickness up to 300 feet. The Hans Lollik Formation, which consists of at least 10,000 feet of augite-andesite pyroclastic rocks, crops out on Little Hans Lollik Island. Dioritic plutons are located in Pillsbury Sound between St. Thomas and St. John; in the narrows, between St. John and the British Virgin Islands; and south of St. Thomas. The exact delineation of these plutons is uncertain. Throughout the islands isolated dikes of quartz-andesine porphyries, andesine-hornblende porphyries, lamprophyres, breccias, and pegmatites appear. Folding occurred after the deposition of the Virgin Island Group. Rocks were tilted to form a northward-dipping homocline, which is cut by sets of faults trending N 45°W, N 55°E, and north. Well-defined joint sets parallel each of the major fault trends. Dips range from 15° to 90Q with the a11erage being 40Q. Strike-slip faults have horizontal offsets of less than 1 mile. Two major strike-slip graben structures or fault systems exist. The first passes through Redhook, St. Thomas and the eastern tip of Lo11ango Cay. The second crosses St. John, from Contact Point on the southwest to Brown's Bay on the northeast. Most recent Pleistocene to Holocene alluvial deposits occurred primarily in coastal embayments. However, a narrow bank of alluvium extends up to Turpentine Run on .the east end of the island. Most of these deposits are composed of silt, clay, and thin, discontinuous beds of sand and gravel. Maximum thickness of these is 50 feet. Groundwater movement is limited to openings and joints along fault zones. Regional geologic information is insufficient to determine whether these fractures and fault zones are present in all of the abo11e formations; however, for this report it is assumed that the fractures and fault zones are present in all of the formati~s. The-valleys on the island are the result of weak zones caused by faulting and jointing anl are primary recharge areas for groundwater. Alluvial deposits have a high porosity but low permeability, making this aquifer unfa11orable for groundwater production. In coastal embankments throughout the island, saltwater intrusion is widespread in alluvial deposits. In most areas, alluvial deposits are interconnected with bedrock and act to recharge precipitation to the underlying bedrock. The direction of groundwater flow in the Turpentine Run Basin Aquifer is south-southeast which is generally along the direction of flow of Turpentine Run. Depth to groundwater in the aquifer ranges from 5 to 60 feet, and the altitude of the water levels ranges from 1 to 209 feet abo11e mean sea level. Ref. Nos. 10, 14 3. Is a designated sole source aquifer within 3 miles of the site? No sole source aquifer, as designated in the Federal Register, is located within 3 miles of the site. Ref. No. 7 4. What is the depth from the lowest point of waste disposal/storage to the highest seasonal level of the saturated zone of the aquifer of concern? The lowest point of the waste oil storage tank is unknown. It is assumed that the bottom of the tank is at least 6 feet below the ground surface. Depth to groundwater in Four Winds Shopping Plaza Well Nos. 1 and 2 is 13 feet and 9 feet, respectively. The Four Winds Shopping Plaza wells are located approximately 400 feet from the Tutu Esso facility. The depth from the lowest point of waste storage (6 feet) to the highest seasonal level of the saturated zone (9 feet) is 3 feet. Ref. Nos. 1, 2, 8 '!, .. lJ20 SUM.MARY APPRAISALS OF THE :-JATION'S GROUND-WATER RESOURCES Wm eout to R1oG...- 0te Are<obo t'r)."('1p1L.t.wn __________________ I.~ :-,treamrluw ___________________ ,-,lo U1vt"n1uns ___________________ _ i:.:.Ylpulrup1n.lton -------------- 1.-tlU Slrt-am ,,utnuw ~ 1;ruund·watrr luu lo Wt'Llanda or~•______________ 15 tin,und-walA!'r w1thdrawata 1 r .. 1a1 tu Industry ·····-··-··-······-- ~ lrnl(&tlun __________________ _ Publ1< supply ····-···----·--· I 7:1 0 ~7.0 til.3 37.6 TABLE 4. - Water ~t. 111 cubic liect~ per ~cir (l&m1lyr) and perCfflt. fcrr P-u,erto Rico 1by Rio Grande de A rectbo to Rio oe L& Plat& hm'lyr Per«nt I .!t!tl I .U:JO J.7 ~-6 Riu do L& Plata to IUo £iiptntu Sanw hmJ/yr P•rttnt Input ti-;'(} '>J.l .-)~ •ti d Ouq,ut IUO .::u nu 7J 0 .N !ti .N I 6 15 Puerto Rtco South Province Patdlu Tallaboa to to Ponre Guanica hmJfyr Perce-nt hm'lyr Percen, 110 .-,oti 60 ~.5 j;IO J~.5 175 14.5 1IO ~.~ ~JO oJ.l 60 ~.5 I~ :!3.5 100 42.S LO l.5 15 6.4 170 !1.0 60 2U I~ 21 143 J7 d 2 L&iu WHt(oat Vali.y proYlnn hm'lyr Perc.nt hm•1yr Percent LUO ;i ~ ttiO !'Ju H I.! - 71 U J:l ~ .. u !LO ,; J .!70 Ll.d II so ,w 74 l 6.3 4ti •o J.l to d tu 1 All l(ruund waLt.-r withdrawn wu •-ufflt'd to IA! for eunwmpuun sinC"t' 1t ts nut ava1lavk!' fur ulh~r u..s. 1000--....... ----,-----.----,---..--....... ----,---- 100 IC C 100 "' ► IC "' ._ 400 .. IC "' ... I zoo 0 ... u ... % 0 u • ::, u ! .,; 400 ~ C I IC Q % !:: • Public SupplJ (Pulfto Rico Aqueduct and Stwtr Authority) TOTAL WITHOll.laU. : : J 1990 19'5 2000 A 2,,---"'T""---,,--~---,-----.---r---..----- 20 I " ... >- 10 C : , -... LltNT INOUSTIIY __ ,,, \ -- -- --- ... OOIIUTIC AND COltlltlUCIAL ... : o,._ _ ___. __ __._ __ ....._ __ ....._ __ _._ __ _._ __ _.__~ ► ~~-----..-------------..--- ► :;: 41 z u 40 • a JS • ~30 ... ~2' • = 20 Q ~ ,, i IO , ?990 TOTAL WITN!Mt-ALS (hclffnHlf• ..... iN i...,, ..... ........... ... .,, 19?1 lt«I IH!J YUIIS 8 1910 ltff 2000 f'1,.1 Ht 17.-Wat.er-use estimates. A, Fur Pu~rto Rico; public-supply data provided hy tilt' Puerto Rico A,1ueduct and Sewer Authority (moriiti~I from Morris. rn76). B. For the U.S. Virgin lillan,L~. CARIBBEAN REGION l'21 prov111tt) afld ita ojJMON "'4IMU (Vieqlu,, CIIUbra. afld MO'llll lslaflds) afld for tJae U.S. Virgin /slanda. 1975 PUt-rLu KK."11 - CunllnUt"II l'.S \. 1rl{111 1~1an,1, Pue.•rt.u H.K .. •~ urfshuno •~lar\(f, ~ul(.;.uu.L In- Pu.-rt.u k,ar,, 1'1antlLuLJ&I V""l'I"> Cui<-t,n, M,,nc1 :--1. lrtll). SI l'homa., . :,,.l Jnhr1 µn1Yln<'l" t:!"'''llfk,- hmJ1,r Pt-r<'t-nl hm'r"·r Pt-rt"t'OI hm.1'\r Pt'rrt'Ol hmJ/~r Pt'n·t'nl hm'1)r Pt'n·""nl 11m••\1 Pt>nt·nt t,m• \I Pt'n·,·11l hmJ•,, Pt'n1·111 l'lffl'\r t-'t-111·Pt lnpu1-Contin~ J!KJ 43 J I0.1f;'O IUO 15.K~ IUO l.!U IUU i;!:, IW ";, 100 ~o IUU ~--) I'-"' 111111 :})(I 56; Outpul Continued :liM 31.U 6.5ll 5S S 10.1;,, ML 110 ijJ.j l4.II 580 &I 4 4.34l JS S 5.U4ti Jl.S :1.U JU 3.J lt,0 l.h :13 'l..i 12 I 3 16 :1511 l.3 h .04 IU 4 ,, .. L 188 ll hh PROBLEMS AFFECTING USE OF WATER. RESOURCES MANACI.MI.NT-PUI.I.TO RICO By adoption of Law No. 23 of January 1973, the Puer- to Rico Department of Natural Resources (DNR) was charged with the responsibility for implementation of the operational phase of the public environmental policy of Puerto Rico. Law No. 23 also provides for centraliza- tion of operational functions and implementation of regulations that had previously been dispersed throughout many governmental agencies. In addition, the new Water Law, No. 136 of June 3, 1976, assigned to the Secretary of DNR the responsibility to plan and regulate the use of and to improve, conserve, and develop the waters of Puerto Rico. In acknowledgment of the need for a centralized information center, the new water law also stipulates that the Secretary be assisted by a staff that has representatives from the Planning Board, the Puerto &ilo, Industrial Development Com· pany (Pruoc:: l:ronmenbd Quality Boord (EQB), the Puerto ~t and Sewer Authority (PRASA), the ' _ Water Resources Authority (PRWRA), the . t of Agriculture (DOA), the Department of Heaftl (DOH), the Department of Trans- portation and Public Works, and the University of Puer• 1 to Rico. Although numerous government agencies (State and Federal) and institutions are involved in the use, plan-I ning, management, and investigation of the water resources, the DNR. EQB. U.S. Environmental Protec- : tion Agency (EPA). PRWRA, PRASA, Puerto Rico! Sugar Corporation, and heavy water-use industries j S5 • JIJ ;, !'ti I" ., .. -. SJ~ SI ';I'(.!, lS I) u " J.h :.!ti IL ~.-. LL! 5 ;, "t,.:, L! 1 ,} ' I I j established by PRIDCO exert the greatest influence over the future of this resource. The responsibilities these agencies and public corporations have with respect to water resources are listed as follows: DNR. The functions of this Puerto Rican agency were established by Laws No. 23 and No. 136, previously stated. EQB. This is the Puerto Rico policy-making and regulatory agency responsible for the enhancement and protection of water quality; it is invested with quasijudicial powers to enforce its regulations. For purposes of the Federal Water Pollution Control program (Public Law 92-500) the Board is designated the State water-pollution control agen· cy. EPA. This is the Federal agency charged with ad- ministration of Public Law 92-500 aimed at restor- ing and maintaining the chemical, physical, and biological integrity of the Nation's waters. Among the programs the agency administers are establish- ment of effluent limitations, administration of the National Pollutant Discharge Elimination System. and management and planning for public water- supply treatment-works construction. PRWRA. The authority produces and distributes elec- trical energy and administers and operates the irri- gation systems supported by releases from reser· voirs and the hydroelectric power-generation net· work on the south coast and in northwestern Puerto Rico. PRASA. The authority is charged with developmenl. construction, operation, and maintenance uf water and sewer systems and providing adequate water { ,rq/0 fr ~fl" U22 SUMMARY APPRAISALS OF THE NATION'S GROL'ND-WATER RESUL'RCES and sewer services and any other related services and facilities. Puerto Rico Su,ar Corporation. A public corporation created by legislative action in 1973 to consolidate the operations of the sugar industry (cultivation and refining). The corporation manages all the 11 mills on the island, 7 of which are government owned. The corporation also manages cane cultivation on 29,600 ha of both government-owned and leased land. PRIDCO. This is the principal Puerto Rico governmen- tal agency charged with the responsibility for the economic development of Puerto Rico. With its associated public corporation, the Government Development Bank, it devises methods to accelerate economic development, especiaJ!y through industrial promotion and tourism. This agency must submit to DNR and EQB an environmental-impact statement for each industrial project it proposes to develop. The agency also cooperates closely with the Plan- ning Board in preparing its plans and programs. The new centralized form of management stipulated in Law No. 136 of June 3, 1976, is intended to improve in- stitutional structures to aid optimum water-resources development. MANAGIM!.NT-U.S. VU.GIN ISLANDS In the U.S. Virgin Islands, the Department of Conser- vation and Cultural Affairs is charged with the ad- ministration and enforcement of all laws relating to water resources and water pollution, under Title 3, Chapter 22, of the Virgin Islands Code as of June 4, 1968. Other agencies involved with the management of the water resources are the Public Works Department, the Water and Power Authority, and the Virgin Islands Planning Office. The functions of each of these are outlined as follows: Public Work• Department. Under Title 30, Section 51, of the Virgin lsJands Code, the Commissioner of Public Woru if dilliarnated to mpervise and control the co=l::ns.....-r, maintenance, operation, and adm · · of the potable-water systems. The po . wyst.em wu defined as "all fresh water storel"'_dt-' eeUected by the government, whether in cat.dnnenta, dams, wells, or reservoirs, for public distnbution." Virgin Ialancla Water and Power Authority (WAPA). This authority was established in 1964 under Virgin Islands Code, Section 103, Title 30, for production and distribution of electrical energy and provision of potable water from its water-distillation systems. In the enabling legislation is a provision, 104e, for the transfer of the water-supply functions of the Public Works Department to W AP A at a date to ~ deter- mined by law. The transfer of functions has not been acted upon by the legislature. and WAPA sells the distilled water to the Public Works Department. U.S. Virgin IsJands Planning Office. This office is designated as the government agency in charge of water-management planning; the agency is also en- titled to appropriate funds received under the title 3 program. The Public Works Department is by far the major ground-water user. Agriculture is almost nonexistent in the islands, and industries that depend heavily on water obtain their water from self-owned desalination plants. For these reasons, a lack of coordination among water users is not a major problem affecting ground-water resources in the Virgin Islands. WA TEil lllGHTS Water rights and laws regulating water use have been established by society to assure the minimum re- quirements of individuals and communities, to promote the beneficial development of water resources, and to respect legal access to water sources. These laws, which have been implemented to reduce friction between users, ironically become constraints if they are not adapted to the needs of a modem technological society. On June 3, 1976, the Commonwealth Legislature approved the Law of Waters (Law No. 136) for Puerto Rico, which declared all waters within Puerto Rico the patrimony and wealth of the People of Puerto Rico; en- dowed the Secretary of Natural Resources with the power to plan and regulate the use, conservation, and development of the water resources and to implement the public policy and regulations related to the waters of Puerto Rico; and annulled two provisions of the Civil Code and the Law of Waters of March 12, 1903. The 1903 water law was essentially that which had been in effect in Spain since 1879 and had been extended over Puerto Rico by order of the King in 1886. Article 16 of Law No. 136 recognized acquired rights that make beneficial and reasonable use of water and were in ex- istence prior to June 3, 1976, including those conces- sions from the Spanish Crown. Acquired rights under the old Spanish law were ob- tained according to the prior-appropriation doctrine. For example, "any landowner may utilize the pluvial and other waters flowing intermittently in public channels or along roads" (Art. 6, 176, 177); "after use for one year and a day, he establishes a temporary right that is superior to that of any subsequent user," on the principle that first in time is first in right (Art. 7); "after water has been used without interruption for 20 years, the appro- priator acquires the right to continue the use indefinite- CARIBBEA:-S R!'.:GIO\ ly" (Art. 8). Similarly, as to "artesian wells. tunnels. or I galleries," (major ground-water developments as oppos- I ed to "ordinary wells," which are defined (Art. 20) as I those for which no other motive power than man is I employed for raising the waters), the right of the person · discovering and bringing the water to the surface is recognized "in perpetuity ... as long as such development does not interfere with preexisting rights to public or private waters (Art. 23). These rights (surface- or ground-water appropriation) were also recognized for all individuals who had enjoyed the use of public waters for a period of 20 years (prior tu 1886) even though no proper authorization had been obtained. The order of preference in utilization stipulated by the previous law (Art. 160 of the Spanish Water Law) ex- pressed the needs of the past century. First priority was given to water supply of towns, followed by water sup- ! ply of railroads, irrigation, navigational canals, mills and I other factories, ferry boats and floating bridges, and fishponds. The economic importance of water-using in- I dustries was not foreseen, and a low preference as to water concessions was stipulated. Duration of the con- ' cessions was limited to 99 years of town supplies (Art. 170) and all other uses but was "in perpetuity" for irriga- tion (Art. 188) and fishponds and also for industry, as long as effluents were not harmful to health or vegeta- tion (Art. 220). As of 1909 there were approximately 250 concessions in Puerto Rico .that were originally granted by the Spanish Crown (Report of the Governor of Puerto Rico, 1909). The majority of these grants were given to lan- downers in the South Coast province for the irrigation of approximately 21,000 ha. The surface-water conces- sions included rights to flood-waters, spring and winter waters, or a definite daily flow. An updated inventory of vested owners, diversion amounts, and land under irrigation is necessary to determine the degree to which these rights could affect a water-use and distribution plan. In the Virgin Islands, all waters are in public owner- ship and are subject to-appropriation for beneficial use as stipulated in··· . Tltle 12, of the Virgin Islands Code. Under this Ml&ed rights are recognized prior to other · . . Vested rights may be nullified by the t1l the Virgin Islands (Com- missioner of C . ·and Cultural Affairs) when it is determined that the exercise of such rights would im- peril health or welfare by endangering, impairing, or destroying available sources of water. Nevertheless, the occurrence of such circumstances is very remote, as most private installations are for domestic use and withdraw less than 2 m3/d. An exception could be those individuals and companies that sell water obtained from I wells. Under Section 153 of Title 12, appropriation per- mits are not required if pumpage is less than l mJ:d for benefinal use. Cndt•r Chapter 3. Title 12. of the Virgin Islands Code. trees and other vegetation adjacent to watercourses are protected by law. This regulation protects the es the tic value~ Pt° stream channels but results in a significant loss of ground water to evapotranspiration by the deep· rooted \·egetation. A modification of this law would be necessary in order to exclude from such provision those watt!reuurses that are used for public supplies or are in hydraulic connection with aquifers tapped for supply. PRACTICES DETRIMENTAL TO GROUND-WATER QUALITY LAND USE Land use may affect recharge tu an aquifer and the quality of its water. Although there has been no exten- sive evaluation of the effects of various land uses on aquifers in the Caribbean Region, data from scattered sources indicate that this could be a major problem in the near future. Urbanization has taken over large portions of the recharge areas of aquifers in metropolitan San Juan, Ponce, and Mayaguez in Puerto Rico and throughout the Virgin Islands of St. Croix and St. Thomas. Unless ar- tificial recharge is provided or withdrawals are reduced to compensate for the loss of recharge, the seawater- freshwater interface will move inland in most of these areas. Aquifers in the Caribbean Region are threatened by pollution from domestic, municipal, and industrial sources. The most widespread source of pollution is pro- bably sewage from cesspools, leaking sewage lines, and overloaded or improperly operating sewage plants. In Puerto Rico about 37 percent of the population is served by sewers, and in the U.S. Virgin Islands approximately 77 percent is served. In en the only areas served by sewers are those within ns. ~ wastes have been discharged to aquifers through sinkholes and disposal wells or have entered aquifers from accidental spillage (D.G. Jordan, written commun .. 1969; R.C. Vorhis, written commun., 1972). Of the 15 disposal wells known to exist in 1972. only Z could be designated as deep injection wells. and the others could better be designated waste-disposal holes. All tht> known disposal holes were between 24 and 213 m deep. Wastes disposed in sinkholes and disposal holes in- clude sewage, oil. neutralized acid, organic compounds, dyes, pickling liquors, pineapple-cannery wastes. and brewery wastes. Jordan (written commun., 1969) estimated there were at least 40 such disposal holes in Puerto Rieu in 1969. It has also been observed that unproductive wells are either abandoned without plugging or are not thor- - - U24 SUMMARY APPRAISALS OF THE NATION'S GROUND-WATER RESOURCES oughly sealed. As a result many are used as receptacles for wastes. The effec:ta on water quality and the extent of damage this hu cauaed in the Caribbean Region have not been assessed. In the Lajas Valley, Vazquez and Ortiz-Velez (1967) observed that a downward hydraulic gradient existed at various abandoned irrigation wells. These wells probably are serving as hydraulic connec- tors between perched water tables and the underlying regional water table. The effect of these "hydraulic con- nectors" on water quality is unknown. Disposal of refuse in landfills poses another threat to aquifers in Puerto Rico. Most landfills were estalished after 1972 (fig. 18), and although migration of leachates may be slow at some sites, with time these will inevi- tably affect to some degree the local ground-water sources. In the U.S. Virgin Islands, landfills have been established near the coast on St. Croix and St. Thomas, and cont.amination of freshwater sources ia not a threat. The landfill on St John, however, ia located in the in- JI' 18"30' 18'00' EXP\.ANATION 6 MI.Wlicipal IOlld ..... ----- CULEBAA VIEOUES terior Guinea Gut Basin, where potential for ground- water development exists. IRJlJGATION PRACTICES Irrigation of crops occurs primarily in southern Puer- to Rico. The basic means of distributing water within cultivated lands is by furrows, although overhead sprinklers are used at some farms in the early months of sugarcane cultivation. Giusti (1971) estimated that ap- proximately 30 percent of the applied water in the South Coast province (Coamo area) was recharged to the aquifer. BeMett (1976) indicated that the ground-water reservoir in the South Coast province is "vertically oriented," in that local recharge and diacharge tend to be high in any given locality relative to lateral ground- water flow. In areas where irrigation water is derived from wells, recycling of the irrigation water will result in an increue in the diuolved-aolida concentration of the ground water. PUERTO RICO 17"45' FtGuu 18.- Solid-waN dilpoal litel in the Carilbwl Rapin. CARIBBEAN REGION U25 During the mid-1960's, drought nearly eliminated surface-water supplies that were used in the South Coast province area for irrigation, and ground-water production was increased to make up the deficit. By 1968, after 3 years of increased pumpage, the ground water in storage was drastically depleted. An estimated 1,000 hm3 of the 1,500 hm3 in available storage had been withdrawn. The depletion in storage was accompanied by a decline in ground-water levels to below seal level over large areas (pl. IA). The chloride concentration in the ground water increased slightly in the more severely depleted areas, but major seawater intrusion did not occur, apparently because of a slight ground-water mound in the coastal areas and the lower hydraulic con- ductivity of the coastal part of the aquifer. Heavy rains later in 1968 recharged the aquifer, but it has never recovered to early 1960 levels. A few areas where ground-water levels were below sea level still persisted in 1976 (pl. lB), but there has been no significant in- crease in chloride concentration indicative of seawater intrusion. OPTIMIZATION Of USE Of WATEll llESOUllCES In general, until recent years the Mfort devoted to optimizing the use of water resources of the Caribbean Region has been minimal. Within Puerto Rico this lack of effort may have been due to the relative abundance of freshwater in relation to demand in most areas. In the U.S. Virgin Islands the poor quality of the ground water and the knowledge that the limited freshwater resources could not meet the demand led to reliance on seawater- desalination plants. Two major approaches are available for optimizing the use of water resources. These are conjunctive use of surface- and ground-water sources and water conserva- tion. The potential for application of such measures in the Caribbean Region is discussed separately. CONJUNCTIVE USI. OF SUUACE· AND GaGUND-WATll. IOIJ&CIS The greatest ~for conjunctive use of surface- and ground-water ' in the Caribbean Region may be on the island of · Rico, where both sources are relatively plentiful.-. _ · a may be achieved by res- ervoir management, 111p1enting natural recharge, ground-water salvage, ground-water mining, and use of seawater. RESEJlVOIR MANAGEMENT Agriculture is the largest single water user in the South Coast province. The estimated ground-water withdrawal for irrigation (180 hm1/yr) constitutes almost 80 percent of the total pumpage. Therefore, the most productive efforts to solve the wwater shortage" may involve an improvement of irrigation practices. To some degree, the irrigation efficiency likely could be im- proved by coordinating the activities of PRWRA with those of the Puerto Rico Sugar Corporation and by changing the priority of the functions of reservoirs serv- ing the south coast. Under present operating conditions, reservoirs are maintained at the highest stage possible for hydroelec- tric generation, thus reducing the runoff-capture poten- tial. With the available reservoirs and the implementa- ~ion of a more efficient water-management system, more water could be made available for irrigation. The hydroelectric-energy loss could possibly be compensated for by thermoelectric generation through burning of bagasse, the plant residue left after the juice has been extracted from sugar cane. During the 1973 fiscal year, PRWRA bought from the sugar mills (which operate from about December to April) 826 million kilowatt- hours of energy generated through burning of bagasse (Puerto Rico Planning Board, 1976). Hydroelectric generation was only about 97.5 million kilowatt-hours during the 1973 f18C&l year, partly by north-coast hydroelectric plants. · AUGMENTING NATURAL RECHARGE Although aquifen receive recharge by natural means, it may be practical in some areas to increase this amount artificially. Within urbanized centers the loss of rainfall infl1tration capacity may be compensated for by con- struction of infiltration ponds, which may also serve for recreation. Flow into the ponds could be supplied from urban runoff or by pumpage from nearby streams. These infiltration ponds could be situated in the upland coastal areas, where coarse sediments (sand and gravel) predominate and thickness of unsaturated material and therefore storage volume is greatest. Areas of Puerto Rico that could benefit most from such modifications are those zones where urban development has decreased the infiltration capacity of aquifen (essentially the San Juan metropolitan area and Ponce). In the San Juan metropolitan area, possible sites would be the San Sebastian outcrop and areas between the haystack hills (mogotes). At Ponce the most favorable area may be near the foothills, where depth to the water table is bet- ween 15 and 20 m. Infiltration induced by this method may make it feasible to establish and continuously operate public-supply wells within city limits, thus reducing dependence on interbasin water transfer. These well fields would also be invaluable in the event of hurricane damage to centralized water-purification and distribution systems. If the recharged water is destined for domestic use, measures would have to be taken to avoid contamination with toxic substances, which may U30 SUMMARY APPRAISALS OF THE NATION'S GROUND-WATER RESOURCES even though ground-water development may be minimal in some areas. Within aquifers for which preliminary areal models have been constructed, monitoring net- works should be maintained to determine whether or not conditions follow those predicted. If significant deviation is detected, the cause can be evaluated and remedial measures can be taken as appropriate. Among the most important needs for improving the knowledge about aquifers in the Caribbean Region are listed as follows: 1. Better definition of conditions within the two major aquifers: knowledge needed about the following: a. Hydrologic relationship between bedrock and alluvium in the South Coast province of Puerto Rico and stream-aquifer interrela- tionships b. Extent of the artesian S!i(stem in the North Coast province of Puerto Rico c. Ground-water flow within the North Coast province west of Arecibo 2. Areal studies made concerning the following: a. Ground-water flow system in Lajas Valley b. Water-balance for unstudied aquifers in the East Coast, West Coast, and Interior pro- vinces c. Water-table monitoring throughout Puerto Rico, the offshore islands, and U .S Virgin Islands d. Qualitative and quantitive asaeument of saline- water reserves of St. Croix and in the coutal aquifers of Puerto Rico e. Chemical-quality data to assess the extent of contamination and seawater intrusion Besides these basic needs, research is also lacking on evapotranapiration and its relationship to soils and vegetation under the climatic conditions in the Carib- bean Region. At present it is unknown if under long- term conditions thick vegetation and plant debris aid ground-water rechalp by reducing runoff, enhancing infiltration, and reduciDc direct evaporation of rainfall or whether ~¥- the soil tlu'OUgh transpiration. litea, surface features, and historical · that water was much more plentiful at now · · · in Puerto Rico's offshore islanda and in the U :v,.p lalanda. SUMMARY The Caribbean Region consists of the Commonwealth of Puerto Rico (8,99o km2) and the O .S. Virgill Islands (3SO..km1). It i1 arnong 6he n1ost densely populated areas in tlle Woi'td, wlU1 an ovetlll populaiton di approximate- ly 3,200,000 peo__£le. Within the past 25 years the islands liive undergone a rapid transformation from an agriculturally based economy to one dependent on in- dustrial development, tourism, and related services. Water is among the most abundant and valuable natural resources in the Caribbean Region, but its availability varies significantly in both space and time. Rainfall contributes an annual average of 1,800 mm in Puerto Rico and 1,060 mm in the U.S. Virgin Islands. Of this amount, 1,130 mm (or 64 percent) in Puerto Rico and 990 mm (or 93 percent) in the U.S. Virgin Islands is lost to evapotranspiration. The water available for use in liquid form amounts to about 5,400 hm3/yr in Puerto Rico and 24 hm3/yr in the U.S. Virgin l§lapds These amounts would theoretically satisfy the total water needs of both areas, which are about 919 hm3/yr and 20 hm3/yr, respectively (1975). In reality, most of this flow is contributed by intensive rainstorms and is lost to the ocean as runoff. Potential for retaining a large part of this flow exists on the island of Puerto Rico, but present- ly the total usable reservoir storage capacity is only about 230 run•. In the U.S. Virgin Islands, small dams and ponds have a storage capacity of about 2 hm•. Aquifers constitute a valuable water resource in the Caribbean Region. In Puerto Rico, ground-water withdrawals provide about 38 percent of the total water requirements, whereas in the U.S. Virgin Islands, they provide 10 -percent. Excluding desalinated-water sup- plies in the U.S. Virgin Islands, (m)Ul!d water rovides t 72 rcent of the freshwa r the 50 hm1/yr -wa r wi wal in Puerto Rico, irriga- tion uses 53 percent; industry, 29 percent; and public water supply, 18 percent. In the U.S. Virgin Islands, ground water is withdrawn about equally from private wells and public water-supply wells. Based on past trends and future economic outlook in the region, · estimates are that by 1985 ground-water pumpage in Puerto Rico will be about 426 hm1/yr and in the U.S. Virgin Islands, about 4.5 hrn1/yr. This withdrawal is the estimated maximum sustained yield of all aquifers in the U.S. Virgin Islands under natural-recharge conditions. Most large-scale ground-water developments in Puer- to Rico are in the North Coast and South Coast pro- vinces. The North Coast province contains the island'~ most productive aquifer, which has been undergoing rapid development for industrial water supply since 1968, when a major artesian system was tapped. The ex- tent of this artesian system is unknown, but it has been tapped within the lower part of the Cibao Formation (Montebello Limestone Member) and in the upper part of the Lares Limestone. The South Coast province aquifer consists of deep alluvial deposits. It has been ex- tensively developed for irrigation of sugarcane and for industrial water supply. Unlike the north-coast aquifer system, which has large untapped resources, this aquifer ·II I'·' l CARIBBEAN REGION L'31 will support only minor future development if effective management practices are not introduced. In the U.S. Vir ·n Islands, the most extensive uifer is ra n I roe . t contn utes 1ttle water to wells, but weighed against the costs of desalinated water, its exploitation is feasible for sup- plementing domestic water needs. The most productive aquifer consists of marl and alluvium deposits in central St. Croix. Although this aquifer contributes less than 6.3 Lis to individual wells, it yields about 0.86 hm3/yr to public water-supply wells and about 0.54 hm3/yr to private wells. Future development of this aquifer could probably produce an additional 1.0 hm3/yr. Ground-water resources will continue to play an im- portant role in the future development of both Puerto Rico and the U.S. Virgin Islands. In order to meet future needs, it is necessary that hydrologic principles be effectively applied in managing the total water resource. Optimization of the water resources can be ac- complished through conjunctive use of surface and ground waters and through conservation practices. Op- timal use may involve artificial recharge, ground-water salvage, saline- or fresh-ground-water mining, use of seawater, wast.e-water reuse, and use of underground space for temporary storage of wastes, which could otherwise contaminate valuable water supplies. Efficient development of the water resources within a basin also requires a thorough knowledge of the rela- tionship that exists between surface and subsurface water. Among the most urgent needs in the Caribbean Region is a computerized data bank containing informa- tion on ground-water withdrawal, consumptive use, sur- face diversions, and such other flows necessary for water-budget estimates. These data can be used with the available knowledge of the aquifers to construct digital or analog models. Such an approach would serve to point out areas where new information is needed, aid in assigning investigation priorities, and contribute to ef- fective management of the total water resource. s 1 ~,UftaENCIS Acevedo, G., Lup,Lapa. " :• udO.U.~ela,J., 1959, Occurrence of soil tumors 111a 6--- J...aaoon. Laju Valley, Puerto Rico: U~ Rico Apicultural Station Jour• nal, v. '3, no. 2, p. lOI-JJ!. Adolphaon. D. G., Seijo, M. A., and Robi11110n, T. M., 1977, Water l'elOW'CeS of Maunabo Valley, Puerto Rico: U.S. Geological Survey Water-Rellourcel Investigations 76-115, 44 p. Anders, R. B., 1968, Reconnaiaance of the water reaources of the Central ~ibo Valley, Caho Rojo, Puerto Rico: U.S. Geolotiical Survey open-file report. 18 p. Anderaon, 1976, Ground water in the San Juan metropolitan area, Puerto Rico: U.S. Geological Survey Water-Relourcel lnv•tip- tion 41-75, 34 p. --19i7. Gruund watt'r 1n tht' La.ias \'aJlt>y. Put'rlu KKv L .:,. Gt"Ulogical Survey Water·Rt>suurct>s lnvt'St1gatiun ti8- 76. 45 µ Arnow. T .. and Cruoks. J. W., 1960, Pubhc Watt>r supµly in Put>rto Rieu: Cummunwt>alth of Put>rtu Rico Wa~r-Rt'Suurct>s Bullt>lm .!. 34 p. Bennett. G. 0., 1972, Gruund wa~r alunic Rio Hucana at Ponct-. Put>rl" Rieu. and t>fft'Cts uf a proposed fluodway un icruund-watt'r quality Commonwealth of Puerto Rico Watt'r-Resuurct>s Bullt>lm 11. 28 µ --1976. Elt>etncal analog s1mulat1un of tht' aqu1ft-rs alonl{ tht' south coast of Put>rtu Rieu: l:.S. Gt>olug1cal Survt-y Opt,n-FII .. Report 76-4, 101 p. Bennett. G. D .. and Giusti, E. V .. 1972, Gruund walt'r m lht> Tor· tugut>ro area. Puerto Rico, as n:,la~ to propo~ harbor construe· tion: Commonwealth of Puerto Rico Water-Resuurct's Bullt>tm 10. 25 p. Black. Crow and Eidsnt'SS. 1976, A watt>r man&gemt'nt µIan fur St. 1111'... Cruix, U.S. Virgin Islands: Black, Cruw and Eidsnt>ss, Inc .. Cun· T suiting Engineen, Gainsville, Fl. Black and Veatch, 1976, Water supply study for entire island uf Puerto Rico, fint phase: Black and Veatch Consultinar Engmeers. Kansas City, Miss. Black and Veatch, Domenech, R. A .. and Asaociates, 1970, Water resources of Puerto Rico, phut! 11. Gl'\IUnd Water appraisal: Black and Vt'Btch Consultinar Engineen. Kansas City. M~ .. and R. A. Domenech and Asaociates, Halo Rey. Put!rto Rico. Bogart, D. B., Arnow, T., and Cruuka, J. W., 1964. Water ~rces of Puerto Rico. a progress report: Commonwealth of Puerto Rieu Water-Resources Bulletin 4, 102 p. Bonnett, J. A., and Brenes, E. J., 1958, Detailed salinity survey of Laju Valley: Univerwity of Puerto Rico Agricultural Experimen- tal Station Bulletin lll, 114 p. Briggs, R. P., and Akerw, J.P .• 1966, Hyd~lugic map of Puerto Rico and ad~nt islands: U.S. Gwlugical Survey Hydrulogic In- vestigations Atlas HA-197, ac:ale 1:240,000. Briggs, R. P., and Seiden, V. M., 1972, Geologic map of the Isla de Mona Quadranglt>, Puerto Rieu: U.S. Gt'Ulogical Survey Miscellaneous Geologic Investigations Map 1-718. scalt' 1:20,000. Buros. 0. K., 1976. Wastewater reclamation project, St. Cruix, U.S. Virgin Islands: U.S. Environmental Protection Agency, En- vironmental Protection TechnulCJKY Series EPA-600/2-76-134, 244 p. Calvesbt'rt, R. J., 1970, Climate of Puerto Rico and U.S. Virgin ~ Islands: U.S. Department of Commel'C1c' Envirunmertal Sc1t>nct> Services Administrative Publication 60-52, Silver Spnng, Md., 29 p. Cedentrom, D. J., 1950, Geolugy and ground-water resources of St. Croix, Virgin Islands: U.S. Geological Survey Water-Supply Paper 1067. 117 p. Cosner, 0. J., 1972. Water in St. John. U.S. Virgin Island~: t:.S. ~ Geoluicical Survey open-file report. 46 p. Crooks. J. W .. Gl'Ul!llman, I. G .. and Buprt, D. B .. 1968. Watt>r rt>sources of tht' Guayanilla-Yaut-u ~. Puerto Rico: Com• monwealth or Puerto Rico Water-Resoun:t"ll Bullt>tm 5, 55 p. Diaz. J. R .• 1968-1974, Ground water levels in the south coast of Put>r· to Rieu (Guanica to Patillas): U.S. Gt-olUl(ical Survey Oata Rt>least' PR-1. San Juan, P.R. --1973. Chemical quality of water in Callo Tiburones, Puerto Rico, A reconnaissance study carried out in 196i: L:.s. Geological Survey ~n-file report fmap). 2 p. --1974, Coastal salinity rt"Connaiuance anrl monitorml(" ~ystem -south cuut of Puerto Rico: lJ .S. Geological Survey Opt-n- File Report 74-1, 28 p. r i. _l , ; J. CARIBBEAN REGION L"31 will support only minor future development if effective management practices are not introduced. In the U.S. Vir ·n Islands, the most extensive uifer is 1 eous roe . t contrt utes 1ttle water to wells, but weighed against the costs of desalinated water, its exploitation is feasible for sup- plementing domestic water needs. The most productive aquifer consists of marl and alluvium deposits in central St. Croix. Although this aquifer contributes less than 6.3 Lis to individual wells, it yields about 0.86 hm3/yr to public water-supply wells and about 0.54 hm3/yr to private wells. Future development of this aquifer could probably produce an additional 1.0 hm3/yr. Ground-water resources will continue to play an im- portant role in the future development of both Puerto Rico and the U.S. Virgin Islands. In order to meet future needs, it is necessary that hydrologic principles be effectively applied in managing the total water resource. Optimization of the water resources can be ac- complished through conjunctive use of surface and ground waters and through conservation practices. Op- timal use may involve artificial recharge, ground-water salvage, saline• or fresh-ground-water mining, use of seawater, waste-water reuse, and use of underground space for temporary storage of wastes, which could otherwise contaminate valuable water supplies. Efficient development of the water resources within a basin also requires a thorough knowledge of the rela- tionship that exists between surface and subsurface water. Among the most urgent needs in the Caribbean Region is a computerized data bank containing informa- tion on ground-water withdrawal, consumptive use, sur- face diversions, and such other flows necessary for water-budget estimates. These data can be used with the available knowledge of the aquifers to construct digital or analog models. Such an approach would serve to point out areas where new information is needed, aid in assigning investigation priorities, and contribute to ef- fective management of the total water resource. uu~:_&UEUNm Acevedo, G., LupLopa. a.a., ud Ortiz.Veles., J., 1959, Occurrence of soil twnon nr-tb •• If_ * Gaaait& Lapin. Laju Valley, Puerto Rico: U~ Rico Acricultural Station Jour- nal, V. '3, IIO. 2, p. 108-111. Adolphaon, D. G., Seijo, M. A., and RobilllOll. T. M., 1977, Water reeources of M.aunabo Valley, Puerto Rico: U.S. Geological Survey Water-Rellourcel Investigations 76-115, 44 p. Anders, R. B., 1968, Reconnaiuance of the water l"NOW'Ces of the Central Guanajibo Valley, Cabo Rojo, Puerto Rico: U.S. Geolop:al SUJ"Vey open-file report, 18 p. Andel'IOII, 1976, Ground water in the San Juan metropolitan area, Puerto Rico: U.S. Geological SUJ"Vey Water-Raourc:ea Inv•tiga- tion 41-75, 34 p. --1977. Gruund water in the La;as VaJley. Puertu K1c11 L ~- Gl'()IU!PCal Survey Water-Resources lnvl'St11fat1un 68- i6. 45 p. Arnow. T .. and Cruoks. J. W .• 1960. Public Water supply in Puertu Rieu: Cummunwealth of Puertu Rico Water-Resuurces Bulletin 2. 34 p. Bennett. G.D .. 1972. Gruund water alung Riu Hucana at Pone.-. Puert" Rieu. and i:,ffl:.'Cts uf a proposed fluodway un ground-wat"r quahl~. Cummunwealth of Pu.-rtu Rieu Water-Resourc.-s Bulletin 11. 28 p. --1976. Ele-ctncaJ analug s1mulat1un of the aqu1fi:,rs alung th.- south coast uf Puerto Rico: C .S. G,,ological Surv.-y Open-fil.- Repurt 76-4, IOI p. Benllt!tt. G. D .. and Giusti. E. V., 1972. Ground water m the Tor· tugueru area, Puerto Rieu, as relatt,d tu prupuse<J harbor cunstruc- tlon: Cummunwealth uf Puerto Rico Water-Resources Bulletin 10. 25 p. Black. Cruw and Eidsness, 1976, A water m~ement plan fur St. IM'... Cru1x, U.S. Virgin Islands: Black, Crow and Eidsness. Inc .. Cun- T suiting En1Pneers, Gainsville, Fl. Black and Veatch, 1976. Wat.!r supply study fur entire island uf Pu.-rto Rieu, first ph11St!: Black and Veatch Cunsulting Engi~rs. Kansas City, Miss. Black and Veatch, Durnenech, R. A .. and Associates, 1970. Wat.!r resources of Puerto Rieu, ph&M ll. Ground Water appraisal: Black and Veatch Cunsulting Engineers. Kansas City, Miss .. and R. A. Dumenech and Associates, Halo Rey, Puerto Rieu. Bogart, D. B., Arnow, T., and Cruuka, J. W., 1964, Water l"4!90Urces uf Puerto Rieu, a progress report: Commonwealth of Puerto Rieu Water-Resources Bulletin 4, 102 p. Bonnett, J. A., and Brenes, E. J .. 1968, Detailed salinity survey uf Lajas Valley: University of Puerto Rieu Agricultural Expenrnen- tal Station Bulletin 11 1, 114 p. Briggs, R. P., and Akers, J. P., 1966, Hydropologic map uf Puerto Rico and ad~nt islands: U.S. Geolugical Slll"Vl'Y Hydrulugic In- vestigations Atlas HA-197, Kale 1:240,000. Briggs. R. P., and Seiders, V. M., 1972, Geologic map of the Isla d-, Mona Quadrangle, Puerto Rico: U.S. Geolugical Survey Mi~llaneuus Gailogic Investigations Map I-718, scalt' I :20,000. Burus, 0. K., 1976, Wutewater reclamation project, St. Croix, U.S. Virgm Islands: U.S. Environmental Protectiun Agency. En- virunrnental Protection Technology Series EPA-600/2-76-134. 244 p. Calvesbert. R. J., 1970. Climate of Puerto Rieu and U.S. Virgin ~ Islands: U.S. Department of Comrnen:-t, Env1runrnertal Scienc-, Services Administrative Publication 60-52. Silver Spring, Md., 29 p. Cederstrom, D. J., 1950, Geology and ground-water rl!SOUrcl'S uf St. Croix, Virgin Islands: U.S. Geological Survey Wat.!r-Supply Papt'r 1067, 117 p. Cusllt!r, 0. J .• 1972. Water in St. John. U.S. Virgin Island\\: C.S. ~ Gieulugical Survey upen-file repurt. 46 p. Crooks, J. W., Grossman, I. G., and Boteart, D. B .. 1968. Water resources uf tilt'.' Guayanilla·Y&ul"O ~a. Puerto Rieu: Cum· monwealth uf Puertu Rico Water·RestJU~ Bullt'lln 5. 55 p. Diaz, J. R .. 1968-1974, Ground water ll'vt'l11 in the suuth coast of Puer- to Rieu (Guanica tu Patillul: U.S. Gt-oiot(kal Survey L>at.a Releast' PR- I. San Juan, P.R. --1973. Chemical quality of water in Calk> Tiburones, Puerto Rieu. A reconnaiaaance study carried out in 196i: L:.s. Geological Survey open-file report (map). 2 p. --1974, Coastal salinity rtt0nnai11sance and mun1turml{ ~yslA!m - suuth cuul uf Puerto Rieu: U.S. Geological Survey Opt-n · Fil~ Report 74-1, 28 p. :u I REFERENCE NO. 4 -- -·~ - - • STD.VE: J!ETEOROLOGY OF THE f"!RGI.V ISL.-LVDS 19 The nature oi the shorter-period pressure variations in relation to the weather and the general circulation are discussed below under The L-pper Air and General Circulation, etc. PRECIPITATION Rain is the climatic element oi most practical concern in the islands be- cause it is oiten insufficient to mature sugar cane in one or two seasons; a drought oi six or nine consecutive months occurs every decade or so. caus- ing much hardship to the townspeople and small native farmers as well as to sugar and cotton estates and cattle ranches. Since early in the nineteenth century rainfall in the Virgin Islands has been measured in a unique unit oi depth, called the "line". The reason for the adoption of this measure is not known. It is an old English measure, in which 1 inch = 8 lines ( == 25. 40 millimeters). In Denmark they once used the Paris measure of 12 Linicn == 1 To1nme (Paris inch) = 27.07 milli- meters= 1.0658 inches.- I Paris line= 2.2S6 mm= .0888 inch= ½u foot, whereas the Danish West fodian (or E11glish) line= 3.17S mm= ¼ inch. It is conceivable that as many of the residents were British this "line., was adopted locally from using English rain-measuring glasses or sticks graduated in eighths .of an inch. Since the American occupation inches have been use<i Accuracy of the Measurements The accuracy of rainfall measurements is a difficult problem in gen- eral, and is especially serious in tropical countries.• \Ve have already re- ferred to the lack of standards in the instruments and observation pro- cedures at Virgin Islands stations. and here we must add that where the are frequently light and the monthly and annual totals are small Q{ measurement are greatest on a percentual basis. The common JK lnea.Suring the catch only once each 24 hours allows some water ' · . e from the gage before it is read. particularly in a warm windy · fie use of a funnel is common and tends to cut down the evapo- rat!OIL Where most of the rain falls at night. it is better to read the gage in the morning, and where it falls more in the day an evening observation hour is preferable; two readings a <lay would be still better, and best of all the use of recording gages or the habit of reading the gage after each shower. It has been shown that a considerable difference in a given • For a comprehen•ive dilCUsaion..,,. Rrooks. C. F .. :--eed for uninrsal standards for meuurinc ~recipituion. snowfall. and snowcottr. Trans. }leer. Int. Comm. Snow and Gacien. lac. A.-. Hydrol. Bull. Zl: pp. l-52. Rip.. 1938. f !. I' I [ . ,,--:-, 20 SCIENTIFIC SURVEY OF PORTO RICO month's total may result at the same spot between a gage read each morn- ing and a gage read each evening. But it is difficult to estimate the magni- tude of this effect in the Virgin Islands except to say that the results from gages read only in the morning are probably somewhat lower than they would be if read only in the evening. The hours oi observation at the vari- ous stations are not stated or known in many cases and at some stations they were changed from time to time. Rain gages of different diameter and different height oi orifice above the ground do not give comparable catches, but it is believed nearly all the gages used in the Virgin Islands since 1870 havt! been of the standard 8-inch diameter with rim about 3 feet high (cf. appendix A). The wind eddying around the gage may keep away some of the rain that should go in the gage. In windy places the catch may average 20 per cent too low from this cause, but we judge from tests made elsewhere with shielded gages that this error in the Virgin Islands probably does not average over 10 per cent (i.e., readings are 10 per cent too low on average from the wind effect alone). If we may assume that this error applies roughly equally to all the gages in the Caribbean region, it may be overlooked in practical comparisons. However, the error due to wind effect increases as the wind velocity increases and therefore the catch during severe storms, hurri- canes, is apt to be more than 10 per cent too low. High wind sometimes blows the gage over resulting in loss of a large catch of rain. Occasionally during heavy rains the gage may overflow before it is read. Considering all these sources of error, it is evident that on the average the recorded rain- falls are systematically lower than the true rainfalls. In addition there may be mistakes and falsifications on the part of ob- servers, which a.re unsystematic in their effect on the results and largely hidden in the averages. An inspection of the daily entries and the reputa- tion of the observer are the only bases for accepting observations as genu- ine, where the stations are not under regular inspection of an efficient na- tional weather service. We have not found any record of inspections by the Danish government, and the U.S. Weather Bureau inspections have been too infrequent to be effective. General Distribution From APPENDIX TABLES 2 and 3 we note that the mean annual rainfall differs considerably at the various stations, ranging between about 3.5 and 70 inches. The absolute range between driest and rainiest years at these staticma is not much larger, however, the extreme annual totals ranging -~.about 25 inches to nearly 95 inches (APPENDIX TABLE 1 ). If we had -~A - ..,, .~1!. STO . .. ,... . GJ. records from e tremcs woul t inches. A rai--", The sea.so,uu in ~fay or J 1 muchmor~~ n on reco, ,die month ; even ~ tions ( see T :· sections of ::,~. rain fall from fl west, but fr : middle was ..: shift in the rel south of eas1 1 peratures at graphic effects E. Taylo1 • 1888: 42) SU! J RJCO ::i gage read each morn- to estimate the magni- ,y that the results from l:What lower than they JiJservation at the vari- ·~ and at some stations :.;ht oi oririce above the l1elieved nearly all the been of the standard •pendix A). The wind he rain that should go · ~e 20 per cent too low ,ewhere with shielded docs not average over werage from the wind 1 · OughJy equally to ~Iced in practical increases as the wind severe storms, hurri- . -figh wind sometimes of rain. Occasionally read. Considering all ge the recorded rain- ns on the part of ob- , e ~esults and largely tnes and the reputa- ·bscrvations as genu- m of an efficient na- rd 0_£ inspections by ~u inspections have iean annual rainfall tween about 35 and niest years at these nuaJ totals ranging ABLE l ) . If we had ~ . . -....... STONE: .\fETEOROLOGY OF THE VIRGIN ISLANDS !ID •'.I - '>0 ., ... , 1111 u - •a ~ C • ~ C 0' .. , ,.,.f. ,- Ftauu Z. Raillfall map of St. Croa, 19%1-30. (From Shaw, 1932.) 21 records from eastern St. Croix and from the mountain tops, these ex- tremes would be greater, probably reaching from 15 to more than 100 inches. A rainfall map of most of St. Croix is shown in FIGURE 2. The seasonal distribvtion generally shows two maxima, a smaller one in May or June and a larger one in October. The winter minimum is much more pronounced than the summer one. The lowest monthly amounts on record indicate that severe drought conditions can occur in almost any month; even October has sometimes had less than 2 or 3 inches at most sta- . . tioas ( see TEXT TABLE 4). Rose points out that the middle and western ~ ul St. Croix have somewhat opposite tendencies in departum ol fall from normal- from 1903 to 1908 the middle was drier than the but from 1909 to 1915 the middle was wetter, and after 1915 the middle was again the drier. This may possibly be due to a quasi-cyclic " · abift in the relative frequency of winds from slightly north and slightly south of east. which would be accompanied by changes in the average tem- peratures and humidities of the trade winds as well as contrasted oro- graphic effects. Forests and Rainfall E. Taylor in his "Leaflets from the Danish West Indies" (London, 1888: 42) suggests that St. Croix formerly had a greater rainfall be- ! 1. J T I 1 \ 22 SC!E.VT!I'!C SCRVEY OF PORTO RICO ca.use an ea.rly book on the islands by Oldendorp ( l 7ii) n:pom:d a. greater amount oi forest growth tha.n is now found. Although a change of climate is rossible, the present condition is better explained by the known destruc- tion of the forest by the inhabitants. TEXT TABLE 5 shows no pC'nna11c11t change in the rainfall oi :St. Croix since 1852. St. John and Tortola have the most forests at present because they are too mountainous for economi- TEXT TABLE 4 FREQt;E:SCY OF .\(o:s:TIII.Y R,\1:-IF.\LL TOTALS GREATf.R !'H.\:- ::Jl'ECIFIED .-\~rnc::-ns, ST. Cao1x Average of 3 stations ior 63 years, 1852-1914 (From Ravn) ~!ontb S umber of yean witb raiofall Ovtt 20 lines Ovtt 40 lines Over 60 Jines (Z.SOin.) (5.00 io.) (7.50 ia.) Ja.auary Z5 z February lJ I lfan:11 13 I Al)ril JJ 5 l :'>fa, 37 Z4 11 Juae JS 19 9 Jul, .. u l Auc,ist so zz & September 57 Jl 10 October 60 JI Ia Sovember 54 JO 13 December J9 11 4 cal sugar-cane culture, though at one time both were under considerable cultivation. There is no reason to believe that either St. John or Tortola receive much more rain than St. Thomas or St. Croix merely because they are now more forested. Indeed, the rainfall observations ( cf. APPENDIX TABLES 2-6) lend no support to that notion. Orographic Effects The rainfall increases with elevation on aU the islands. as residents and travden can readily obser\'e and as one would expect. But rain-gage sta- tions areucking at high elevations, except Pearl. Mafolie. Liliendal, \Vint- bcrg, and Dorothea. Shaw's rainfall map (FIGt'RE 2) based on rainfall records (see APPENDIX TAllLE 7) of sugar estates on St. Croix leaves no doubt that even moderate elevations are better watered. Yet the rate of in- crease of rainfall with elevation does not here seem to be as large as in the parts oi Porto Rico where the mountains rise steeply to 3CO) feet or more .,, directly in the path of the pre\'ailing winds. Rose suggests that the rain- fall oi the islands is not as great as one would expect from the topography because the winds blow mostly parallel to the mountain trends. The reason r l...i I ... >< _ ... ( r. -, ri; -< i: ,. ~ r. V ., 0 .:; rt' -, ii -· rt ;..; rt 5 .fo.~;;Oc.w '°{ j 5. U> :r. 'O ,.. JQ ~ g- f "' :--· ::r (') "' 0 ;~ n n ~ 0 n 0 ;.. ::i ::i ::i ,.. ,.. ::, ~ > 0 0 ;,: -· ., 0 0 aq ., s:., ~ ::, /i ;· 0 .... ,. 0 .... :-~ n ., 0 ~ (1) '; "' .. µ ., 'ti ,::: "' ~:: ., ~, ~ ., ., ~ =· 7~ ~ 'ti ., 5: :, ;1 ,~ "' -~ µ µ ., ~ C ri ~ ("C U> Pl (1) 0 n ,, ,,, ·r:1 f!. <:~ ,,. ~ "· :,: g. ;:i ., I'' ,, , ,:, .. ~ s:., 0 "' ;, !1 ·i ;:.J '-: ,, 'I ;,; ~ ::i 0 £: :1 ' n, ' C, - Q. ;< (1) iu /l, ' '< (l) 'I I. ··d•· Tt:XT TABI.E 5 Avt:IIAGt: RAINt"Al.L tuK E11c11 IO-Yu11 Pt:11100, 1852-1911 (IN INCllt:s) • "St. Croix, Virgin lslamh" = (Chrislianskil's Fort+ Kini:~ Ifill•+ F11·1lnid,,1nl\ h,11 JI.I (From L. Smith) Period J•n. f'eb. I.tar. Apr. May June July Aus. S,p1. Ocl. Nov. Dec. \'ur ,-<'---==-- IISl-61 I 90 I 60 1.68 J.12 S.H l.76 J.SI ◄ 92 7 26 8.16 ◄ 41 2.68 r N 1162-71 2.11 l.6S l.l6 2.06 JJS l86 J.10. 4.18 5 26 7.SO ◄ 07 l 40 J 00 w 1872 811 2 85 JH 1.57 l.4l 4.16 4.41 l.37 4 ZS S 28 S.11 6 61 l .ll ◄ 86' lk82 911 1 18 2 10 I.IS l.17 J.22 l.97 4.06 4.62 4 92 1.10 S 92 l.67 7.50' 1892 1901 2.16 1.45 1.12 1.IS 6 Jj 4 60 S.42 4.S8 6 81 H7 546 4.08 9 87 1902 II U2 2.ll 1.12 2.52 4.26 J.40 2.47 5.40 6 91 ◄ 68 ◄.96 S.OS 7 .62 - ---------- Tui..l 14.JJ 11. ◄S 10.21 IS.SI 26.90 24.08 21.95 2811 lb 4S H 38 31 H 21.11 281.JS .\vtra,:r for 60 Yt:ilU (1852-1911) 2.18 1.91 1.70 2 60 ◄.◄7 ◄ 01 J.6S 4.70 6.07 6.56 S 23 J.Sl ◄6 89 - ----- ·----· - ----- • Thr:--c"" are from lbt Yme ob>t•rvalions u:,ed in 11xr T48L£1 l9 loll, here converted to inches from the 111inn" in 111,hich r.tiuf.all w.is nu:a)urtd (8 lint>::....:.... I lnLh). From "ke1iorts of the Vir1in hhmd, l::11wrimc-nt Station, 1911 ", f Kinp Hill w•• omhlrd from 1he avtra1H for Ocl. 1178 lo Oc1. 1886, inclusive. 24 SCIENTIFIC SURVEY OF PORTO RICO for this may also be contained in some observations oi the writer: on sev- eral occasions during his stay at St. Thomas in June, 1939 when the sum- mit of the island ( 1800 feet) was visited. he noticed that any large cumulo- nimbus cloud that had been initiated by iorced ascent oi the wind over the island would lean to the leeward so that most ot the rain falling from it would fall on the ocean surface somewhat to the lee of the island. In other words the orographic influence on the r:i.iniail was not fully enjoyed by the island itself owing to its small size and narrow form. This observation is confirmed ( oral communication) by Ser~eant Davidovic. the Aerographer stationed at the U.S. :\[arine Corps Fleet Air Base on St. Thomas in 1939. In general the annual rainfall does not seem to increase more than about 10 inches between sea level and IOCO feet elevation, but some of the lower stations have as much rain as places high up on the leeward slopes or in high protected valleys (compare Adrian and Cinnamon Bay, or Barracks and Liliendal. in tlte same years) ( A.PPE~orx TABLE 2). In generally rainy years or months the rainfall differences between stations oi different ele- vation arc much greater than in generally dry seasons. At the U. S. Marine Corps station on Lindbergh Bay three rain gages have been set a few hundred yarris apart in a line from the water to the foot of the mountain. These gages show a decided increase in rainfall (AP- PENDIX TABLE 12) as the mountain is approached, although they arc all about at the same elevation. This demonstrates how sensitive the rain- producing process is to the topography. For this reason, within the hilly town of Charlotte Amali~. o~~i Ch~~~~ !!iuvcragc annual rainfall probably varies considerably ( up to 5 inches?) from block to block; hence records taken at different spots in such a town cannot justifiably be com- bined as if from one station. Likewise different parcels of an estate often have very different rainfall ( e.g., Eden, Emmaus, Caroline; Adrian, Su- sannaberg). We have not attempted to construct rainfall charts of St. Thomas and St. John owing to the non-homogeneity of the records. Shaw's map of St. Croix (ncuu 2) is based on a homogeneous though short (10 years) series of 26 records from the flatter pans of the island, which should give a reliable and consistent pattern. Year to Year Variation The variability of the mean annual rainfall is of prime economic conse- quence because in over half the years the actual rainfall is well below the normal rainfall,• which is just about sufficient for an annual yield of sugar • It is characteristic of the frequency distribution of either daily, monthly or anaua.l raiafalla, that the moot frequent -.alue <"""'•) ia ~Uy mud, lesa than the anrap, and in - cua tlte zen, ftlue ii - frequent. rur ,)() __ ,_ STO.\'F. . . c:me. iong the chief er, discusses this prob· n low). Du Tertrc ar C the poor crops of lS+i 1923 to 192+ were ,1,_t• trary to the imprc: c• evidence that the r.c.i1 to century ( see Fores has not been scien ~, show long quasi-p ir rainfall. These un<lou enough to reveal ar I near the critical lirr tuations are important understanding of the for the farmers me I:, attempts to foi ,. t derived from analysis for long-range for a solutions offered d, 1c plicability, however p1 The most successi"' r places, none of whi I The diurnal dist 11 greater amount of ·-i· toe's observations at Tidende", 1888. H, ~ NrGHT }(oath (I Saa J July Aucu,& Sei,teailltt • In lines~ a Iii The frequency o r is probably not so l ) heavier. TO RICO ,ns of the writer: on sev- ·.me, 1939 when the sum- ~d that any large cumulo- ~ent of the wind over the · the rain falling i rom it ee of the island. In other · not fully enjoyed bv the mn. This obsernti~n is :idovic. the Aerographer eon St. Thomas in 1939. ncrease more than about n. but some of the lower the leeward slopes or in 1amon Bay, or Barracks .E 2). In generally rainv :ons of different eJ;_ -· .,.-h Bay three rain gages -~ from the water to the increase in rainfall (AP- !. although they are all 10w sensitive the rain- reason, within the hilly wcragc annual rainfall n block to block ; hence not justifiably be com- reels of an estate often Caroline; Adrian, Su- ,ts of St. Thomas and ·ds. Shaw's map of St. ugh short (10 years) nd, which should give •rime economic conse- 1 fall is well below the annual yield of sugar -no11thly or an11ual raiaWla, erace. and i11 10- ca- the --- STO.\'£: .\!ETEOROLOGY OF THE VIRGIN ISLANDS 25 cane. long the chief crop, and the cane yield suiters accordingly (Dr.Shaw discusses this problem with respect to St. Croix, in paragraphs quoted be- low). Du Tertre and Oldendorp mention great droughts in 1661 and l,53; the poor crops of 18-tl, 186-+. 1869. 1872 to 18i7, 1891, 1892. 1899, l904. 1923 to 1924 were due to low rainfall ( see TEXT TABLES 20 to 23). Con- trary to the impression oi many residents and travelers. there is no real evidence that the rainfall is slowly and steadily decreasing from century to century (see Forests and Rainfall). The question of cyclic variations has not been scientifically studied here, but results elsewhere generally show long quasi-periodic iluctuations of considerable amplitude in the rainfall. These undoubtedly exist here too but the records are not long enough to reveal any but the shortest "cycles". The average rainfall is so near the critical limit for sugar cane that even the small short-period fluc- tuations are important. It does not contribute much either to fundamental understanding of the variations nor to practical precautionary measures for the farmers merely to describe the rainfall curve as quasi-periodic. All attempts to forecast the fluctuations by means of extrapolating "cycles" derived from analysis of past records have been failures. Scientific bases for long-range forecasting arc being sought in many directions but the solutions offered do not yet give results of practical value and general ap- plicability, however promising the method or enthusiastic the advocates. The most successful results so far are for certain special conditions and places, none of which have been in the West Indies. Diurnal Variation The diurnal distribution of the rainfall, as at San Juan, shows a much greater amount of rain by day than by night, judging from Mr. A. Wal- loc's observations at Charlotte Amalie, published in the "Set. Thomae Tidcnde", 1888. He gives the following figures. TUT TABLJ:6 NrcBT AND DAY RAINFALL, CaAJILO'I'TE AM:ALIE, 1888• Moat.b (1111) Toca! 38.4 77.l 69.0 • In Ima; a !ilia= 1 iach. By day 26.I 55.9 44.6 By nicbt 11.6 21.J l4.4 The frequency of rain is no doubt also greater by day but the contrast is probably not so pronounced because the intensity of the day showers is heavier. . i -.i.\ 26 SCIE.VTIF!C sc:RVEY OF PORTO RICO .-\t sea the rainfall frequency is a maximum at 6 A.~r. with a secondary maximum at about 10 P. ~I. The amplitude oi this daily variation is pre- sumablv smaller than the one observed o\·er the islands. where the maxi- mum c~mes in the afternoon. It is Yery likely that the sea maximum at 6 A. ~1. affects the islands. or at least their shoreward margins, causing a secondary maximum at that hour. ~o hourly observations are available from the islands but the sunrise shower seems to be recognized by the residents as a more or less regular phenomenon. The daily double period in the rainfall is of course rerlected in the cloudiness ~ TEXT TABLE 17) and in the frequency of thunderstorms. Intensity and Frequency The rainfall in this low latitude and oceanic situation is entirely of the shower type, and therefore it is of great practical importance to know how frequently showers occur, how long they last, how much rain fails per shower, and what are the average and maximum rates of fall over short periods of time. Unfortunately systematic observations using recording rain gages were begun in the islands only very recently, so we arc forced to infer much from the usual rainfall observations which give only monthlv totals and numbers of rainy days. The average rainfall per rain <lay (A~PE~DIX TABLES 10 and 12; FIGURE 10) indicates some important characteristics. The "showers" of the winter and spring seasons arc characteristically brief and light, often mere sprinkles, from cumulus clouds of small or moderate size and spaced by large intervals of blue sky ( cf. TEXT TABLE 9). Sometimes "norther" effects cause a low overcast cloud deck with driz- zling rain punctuated by occasional heavier showers, which condition may persist a day or two. However, yerx heayy raios HP tq 2 9t 3 iocbcs io a dav have fallen even in the driest months. In the "rainy season", from • lay to ov vier and more enduring showers t under and at times, are to he e. least one s some sort then falls almost every day. Heavy rains lasting as much aa 6 or 8 hours, even with hrief intermissions. are normally very rare, but passage of a hurricane with~_50 or_ lOQ.mjlc'i c:ao cause..enoL- mous rainfall totals (over 10 ingjes.1Jn.a ... da¥ .. ar two from..virtualJy 000- gnuous downpours, The high wind during hurricane weather adds greatly to the destructi,·e effect oi the rain. Somc='9'significant deductions can be made from the results of the re- cording rain gages, in spite of the short period they have been in use. At the .Marine Barracks of Bourne Field on St. Thomas a recording rain \Ui STO.\'E. 1£ETEO gage has been operated since TABLE 12 and FIGwRE l0) c and also per rain hour ior __ c fall during any 2-l- hours of t teresting relation because nlaces we can assume tha :: ~abulated by the l". S. \\·eat'. basis for estimating the a .. ·~-, Since February 1940. t!, ~ rainfall rates monthly from rt estates on St. Croix. An abst and 8. Although the perio, i averages or extremes like!. ,1 study of the tables reveals a c rainfall and the maximun r the average intensitic- -i showers probably hav-.. .non numerous lighter shower~ 1 average intensity to be g 1 months. It will be noted. hu"- months appears to be as hig whereas the total rain fall the spring. This is a cu~ic . ; the greater frequency at ha1 the late summer and- autur . tensity of rainfall will act . because O f hurricanes. The I' excluded, winter and sprin~ tensity as the autumn rain: · riods, as shown in TEXT T •· ~ greater in the "rainy season to infer to what extent t : islands, as the topograph 1 well as the totals. but the Bot to show similar features tc ·' Any practical interpret Virgin Islands. especiall~ or that a large proportion ot thi (secTEXTTABLES9and 1( rain gages and they augm-- significance for crop growtl ' ' ' ~I r. PORTO RICO ,num at 6 .\.~I. with a secondarv ie O f this daily variation is pre-- er the islands. where the maxi- ikely that the sea maximum at r shoreward margins. causing a ,urly observations are available ,;eems to be recognized bv the nenon. The daily double ~riod :oudiness ( TEXT TABLE 17) and ·quency anic situation is entirely of the 1ctical importance to know how last, how much rain falls per um rates of fall over short --obsen·ations using recording ·ery recently, so we are forced ,bservations which give only The average rainfall per rain 10) indicates some important seasons are characteristicallv 1 cumulus clouds of small o 0r . of blue sky ( cf. TEXT TABLE •wercast cloud deck with driz- ,h~wers. which condition may rams up to 2 or 3 inches in a In the "rainy season", from ·ing- showers. with squalls or :pected much more often; at n_o_st e,·ery day. Heavy rains ·r intermissions. are normallv , nr 100 miles can cause eno;- _i· ?r two from virtually con- :rncane weather adds greatly irom the results of th~ re- l they have been in use. St. Thomas a recording rain .• STO.\"E: .l[ETEOROLOGV or THE f'[RGI.V ISLANDS 27 gage has been operated since 1935 .. -\n analysis of the re~ults (.>.rPE::-;or:< TABLE 12 and FIGt:RE 10) indicates that the average rainfall per rain day and also per rain hour ior each month is proportional to the greatest rain- fall during any 2+ hours of the corresponding months. This is a n:ry m- :eresting relation because in the absence of recording rain gages at other places we can assume that the "'greatest rainfall in 2+ hours·•, which is tabulated by the C. S. \Veather Bureau ior all its stations. gives a rough basis ior estimating the a,:eragc intensity of rainfall per day and per hour. Since February 1940. the Soil Conservation Service has been tabulating rainfall rates monthly from recording gages at Anna's Hope and Jolly Hill estates on St. Croix. An abstract of the results appears in TEXT TABLES 7 and 8. Although the period of observation is too short to give any definite averages or extremes likely to occur, the figures are already significant. A study of the tables reveals a closer correlation by months between the total rainfall and the maximum intensities than between the total rainfall and the ayerage intensities. This is not surprising because one or two intense showers probably have more effect on the monthly totals than the more numerous lighter showers. There is nevertheless some tendency for the average intensity to be greater in the rainier months than in the drier months. It will be noted, however, that the average intensity in the spring months appears to be as high as or higher than in the autumn months, whereas the total rainfall is usually much greater in the autumn than in the spring. This is a curious fact which we have already suspected from the greater frequency of hail in the late spring and early summer than in the late summer and·autumn. Over a period of many years the average in- tensity of rainfall will actually be greatest in the autumn or late summer because of hurricanes. The important conclusion is that, if hurricanes are excluded. winter and spring showers probably have as great average in- tensity as the autumn rains, but the ina.rimum rates of rainfall in short pe- riods, as shown in TEXT TABLES 7 and 8, are generally two or three times greater in the "rainy season" than in the winter and spring. It is impossible to infer to what extent this conclusion is justified for all parts of the islands, as the topography may greatly affect the rainfall intensities as well as the totals. but the Bourne Field results (APPENDIX TABLE 12) seem to show similar ieatures to those of Anna's Hope and Jolly Hill estates. Any practical interpretation of the average rainfalls reported in the Virgin Islands, especially on St. Croix, should take into account the fact that a large proportion of the rain falls in light showers and brief sprinkles ( see TEXT TABLES 9 and 10). Many of these light rains are measured in the rain gages and they augment the total rainfall out of proportion to their significance for crop growth and for vegetation because they barely wet ,JUL 28 SC!E.VT!F!C SURVEY OF PORTO RICO TEXT TABLE 7 R.-1.r:,,;FA!.L IxTE~SITIES ~{E.ASURED AT Sr.nro:- SCS ::-io. 13 F. S . .\ .• Jouy Hru. ESTATE, Sr. Camx, V. I. (From U. S. Soil Conservation Service) . --------- Total Tot.l .-\ vera11e ~luimum Intensity for Differeat Intervals Rainfall, Duration, Inten.s.uy, :,Iontb inches .'lours• :n. hr. 5-min. JO-mm. :a-min. 6a-mia. 120-min. - -------- 19~0 February 0.90 l 5.02 a 06 1.00 0 ; 5 O . .JS a.!J :'-larch 0.52 l.92 0.27 .\pnl l.97 ;.42 0.JI 2.00 I.SO 0.80 a.so 0 28 ~lay 7.10 J0.00 0.Z4 J.50 2.00 l.40 1.10 0.70 June J.OS 3.10 0.J8 2.00 I.SO 0.90 o.ss a.JO July 2.14 5.07 0.42 5.00 J.50 Z.30 l.JO 0.65 .\ugust J.05 12.37 0.25 J.00 1.7S 0.95 a.JO 0.15 September 4.19 12.65 0.JJ 7.00 5.00 J.40 1.40 0.75 Octoi>a 7.47 zz .45 O.JJ 4.50 2.75 2.80 1.70 I.OS N"ovember i.15 2S.J7 o.zs 5.00 l.50 2.40 1.4S 0.90 December l.47 20.25 0.17 l.SO 2.25 1.60 0.8S 0.45 1941 January 1.97 5.02 0.39 2.00 1.75 0.90 0.40 o.zo February 0.21 0.80 0.26 ~ I.JJ l.ll 1.t7 I.SO 1.00 a.so 0.18 April z.za 9.45 0.24 J.7S 2.50 1.40 0.56 a.JO • Inteasities of less th.an 0.10 ia./br. are not iaduded. TEXT T.uu 8 RAINFALL bTENSmES MEASURED AT STATION SCS No. 15 F. S. A., ANNA'S Hon EsTATE, ST. Caorx, V. I. (From U.S. Soil Conservation Service) r Total Total Avenge Muimum Intensity for Different Intervals Rainf.a.JI, Duration, Intensity, 60-mia. 120-min. I ~lonll1 inches boun• in.;br. S-mia. 10-m.ia. 20-mia. \1 1940 J;>auary 0.35 2.77 O.IJ I February 2.09 17.18 0.12 1.80 1.25 0.75 0.JO 0.11 I· ~larch 0.99 4.92 0.20 1.00 0.7S O.JS 0.IJ I ApnJ 1.55 4.20 0.J7 l.SO 1.7S 1.20 0.80 0.4J ~lay 2.IS IS.OS 0.19 2.00 I.SO 0.80 0.40 0.25 June 1.56 4.60 O.J4 J.00 Z.25 1.20 0.40 0.20 I July 1.17 4.ZJ 0.28 1.00 0.75 O.JS O.IJ I AUCU3' 1.75 7.48 0.2J l.00 2.00 0.80 O.JO 0.15 September S.24 6.67 0.82 7.00 S.00 4.20 2.30 1.11 October 8.43 22.05 0.JI 4.00 J.00 2.00 0.80 o.so i, Sovember 6.05 14.67 0.41 7.00 s.sa J.JO 1.10 0.60 ' December 2.36 14.10 0.17 I.SO 1.00 0.4S 0.18 1941 2.SO 1.60 0.60 0.JI January l.67 12.2S O.JO 4.00 February 0.19 2.50 o.oa '.\1 .. th I.OS 2.&J 0.J7 I.SO 1.00 o.so 0.20 0.15 .... pril l.41 7.25 0.J4 4.00 l.00 ~-60 0.92 0.41 • Intensities of less thaa 0.10 in./br. are aot iaduded. ' STO.VE: JfE - the vegetation and the t quickly evaporated by th -· PERCE~TAGES C.ar 1 Fr ~oath Janury February ~an:ll April l,lay Juae July .-\UC\ISt Septeml October Sonmber December Year AvE&AGE A:-iD Ex1 '.\loath Janury February '.\lan:h .\pril ~ay June July Auc,ist September October Sovember December • Thee 6gun:, are not ,ua )'1!111' ia the period covered by -·· ,: ..... :.:.,:.:; / ii ~ . .-; .,,,.,,., ·'. JO .)C!E.\"rfrll .) [_"R{'[:.l" or PORTO RICO Evaporation The actual water loss i rnm the ;round by e\·aporation and by trans pi ra- tion of plants is probably high, jud~ing irom the general weather condi- tions and irom the measures oi c;;a('orari11g pu .. ,cr oi the air made at the Experiment :Station ( ,cc .,rrE:--;orx T.\BLE 8). Cunsequently. the roughly +j inches oi measured a\·er;i.i;e ;i.nnu;i.l r;i.111:all in the \"irgin Islands is hy no means the equ1\·aient for :1bnc growth oi +j inches ui measured pre- cipitation in rainier parts oi the \\'est [11dies or :n the southern Cnited States. Thunderstorms, Squalls. and Hail Tlz1111derstor111s occur. as in Porto Rico, chiefly from July to October, according to the records at Christiansted and Bourne Field ( TEXT TABLE 1 and APPE!'l'DIX TABLE 12). Schomburgk in 1837 reported that 5 to 10 per cent of the days in a year had thunderstorms, mostly in September and October. which roughly agrees with the Christiansted data, although at Bourne Field more of the storms occur in July and August. Most storms probably occur in the afternoon. as at San Juan. They are apt to be squally and inflict wind damage at times. but lightning damage is usually slight. Squalls are sometimes associated with heavy showers and probably with most thunderstorms. The familiar downrush of cold air under a thunder- storm or tall cumulonimbus cloud can be so Yiolent as to capsize small boats and damage dwellings, trees. and crops. \.Vhen the observer is located on the sunny side of the cloud. it may appear white until after the squalls reach him, giving rise to the term "white squall" of the West Indian na- tives; but when the observer is under or on the shaded side of the cloud. it appears very dark and ominous. so the accompanying gusts are called ··black squalls''. \.Vhite squalls are also reported without heavy clouds nearby, but these are merely gusts when the trades are blowing strongly. The West Indian sailor well knows that the squalls are apt to be especially \·iolent and dangerous to boats along a coast which rises to high mountains immediately back of the shore. Hail is rarely reported and most residents spend a lifetime in the islands without seeing any. There are enough authenticated reports to leave no doubt that it falls at least eYery icw years. even seYeral times in some years in which conditions are fa\'orahle for it. :Huch hail. with cold and rainy _.,.weather, occurred in Virgin Gorda in January 1833. according to Schom- hurgk, who also wrote of hail on the north side of Tortola in Novemher 1829. Knox mentions that ha.ii as big as hen eggs fell in St. Croix on .-\pril 13, 1844; and that a :\fr. :\"issen told him of a hailstorm at St. STONE: Jt r Thomas on :.fay 13, l~ St. Thomas in 1938. '.: early summer. the c ~- ter and spring; pernar thus more likely to be r- Chemical analyses c , Station from 1911 1 tained an average nitrogen in the form o These figures varie ' The amounts do no1 e appear to depend on t that they are related tc These chemical cor soil and the na ; __ 1 Owing to the sm ration, and the few p obtain domestic wa · 1 and stored in cister: . crete to catch rain to strict e1:onomy in use Shallow dug well! 1 pumped for flushi .. ~ stocked with "mosq,; spread chiefly by 1 of La Grange plan- St. Croix was starte but not on a scales--'" not yet been tried. on which it was usco. Temperatures i- Porto Rican stati< small land area ava.i RICO ::ir. Cao1x, V. I. a) '✓ for Different Intervals .:-min. 60-mm. 120-min. J J5 0.IJ !SO 0.50 0.Z8 140 LIO O.iO J.90 0.55 0.JO . 30 !JO 0.6S 9S 0.JO 0.1S -IQ 1.40 0.15 .80 1.70 I.OS -10 us 0.90 60 0.BS 0.45 0.40 0.20 -- 0.18 -10 0.S6 O.JO . Caorx, V. I. r Different lilt~ n. 60-min. 120-mia. -~-- 0.JO 0.18 0.IJ 0.80 0.4J 0.40 o.zs 0.40 0.20 0.IJ 0.30 0.1S Z.JO I.I& 0.80 o.so I.IQ 0.60 0.11 0.60 0.J8 0.20 0.15 0.92 0.48 - I l STO.VE: }fETEOROLOGY OF THE VIRGIN ISLANDS 29 the vegetation and the top of the soil and do not sink into it, and so are quickly evaporated by the sun and wind. TEXT TABU: 9 PERCENTAGES.OF DAYS WITH SPECIFIED AMOUNTS OF RAINFALL. :\fonth January February '.\la.rch April .May June July Aucust September - October November December Year CaRisTIANSTED, St. Caorx, 1852-1907 (From Willaurnc-Jantzcn and Ravn) ~ ZO mm (}-5 mm (0.79· (0--0.Z0"l or more) ,; 5 64 3 66 4 5; 16 56 10 -16 14 5S 10 54 11 45 15 4-4 18 48 12 52 8 54 II TuTTAJIU 10 > 50mm (1.97· or more) 0 0 0 2 4 J 2 4 4 7 l 2 l AVD.AGE AND ExTUME Nu:MBERS oF DAYS WITH RAIN, CHRISTIANsnn, St. CROIX, 1852-1907 (From Willaumc-Jantzcn) Ripest Lowest :I.loath ~lean in uy oaeyear in any ODe year Jaaaary II 20 z February 9 23 1 March 6 14 0 ~ 7 13 2 II 16 J June 10 20 4 July II 17 4 Aucaat II 17 4 Sepcember lJ 19 6 Oclllber 12 19 6 Sovember 14 20 4 December IJ 19 6 Yeu IZS 111• 34• • These 6sures are not IWllS of the column, above, t>ut are the atreme -i. cm recmd (or any CIIUI year in the period covered by the table. l 1.J ! ,:y.)J.. :,•···,, .,:: .. 1:: . .:.::, 'ewz ~ REFERENCE NO. 5 ._.l, .-' ..i • l CLIMATOGRAPHY OF THE UNITED STATES NO. 60 Climate of Puerto Rico and Virgin Islands ....................................................... ········· : ii 11:m ! m: ........................................... ·········································· ········································· ........................................ ······································· ·················· ·················· ···························· ···························· ···························· ............................ ···································· .............. . ···································· ··············· ···································· ··············· ···································· ··············· ............................ ···································· ··············· ···························· ···························· ............ ···································· ··············· ····························· ········································· ···································· ··············· ······································································· ....................................................................... ······································································· ······································································· ······································································· ....................................................................... ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ······································································· ....................................................................... . . . . . . . . . . . . . . . ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ······································································· ······································································· ······································································· ······································································· ······································································· : : : : : : : : : : : : : : : : ::: : ::: : :: : : : : : : : : : : : : : : : : : : : : : : : : : : : ; :.;.;..: ....... ···················································· :::::::::::::::::::::::::::::::::::::::::::>··· ......................................... .,,, ::::::::::::::::::::::::::::::::::::::? 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CENTER ATMOSPHERIC ADMINISTRATION DATA SERVICE ASHEVILLE. N.C. REPRINTED . 1982 ... ,.··:· .·· "'. .,: ___ , __ .... ;,_ I • Due to the small size of the islands and the location of all stations within a few miles of the water, the mean daily range is quite small, It varies from 9.1° at Charlotte Amalie to 15,1°F at Wintberg. For these same reasons extremes of temperature are not as great as they are in Puerto Rico, and relatively few days have temperatures of 90° For above. Since the extent of land areas is small, the air passage over land is quite short and there is not sufficient time for extreme heating to take place. On St. Croix, Annas Hope has had a temperature as high as 99° F. During the warmest months, maximum temperatures average about 87° to 89° F, with nighttime temperatures falling to about 74° to 78° F, and a little lower at the higher elevations. In the winter, daily maximum temperatures are generally in the low 80's and nighttime minima in the high 60's or low 70's. The highest mean maximum temperatures are found in August, while the lowest mean maxima fall either in January or February. The lowest mean minimum temperatures are observed in January and February, and the highest mean minimum temperatures are generally in July or August. DROUGHT - Drought in the Virgin Islands occurs about as often and is just as damaging as it is in Puerto Rico. None of the three islands has any significant running rivers or streams and only St. Croix has an u~derground water source in a few sections. Water for irrigation is not available in quantity at any time. Large storaae reservoirs do not exist so the Virgin Islands are, to some extent, more at the mercy of "Mother Nature" than is Puerto Rico where there are adequate facilities for water storage. HAIL - In the U. S. Virgin Islands, hail is even leas frequent than in Puerto Rico. In January of 1969 a severe local hailstorm with hailstones up to 1 1/2 inches in diameter occurred. Thia was the first hailstorm on record in the U.S. Virgin Islands. 20 l ; _ _..! I l) 1-.·' -· ----- ------ _, ·- O~ph~~lii.S_ing of the mo~tur_~ _ _l~~en air over the hilly terrain of these islands is the most frequent cause of rainfall: However, due to the smaller elevations- an<f smaTler -size.of the islands, there is a less marked variation in annual amounts. The larger mean annual totals are between SO and- 60 inches at the higher elevations, and the variation between the greatest and least average value is not as marked as it is in Puerto Rico. Clouds formed by forced ascent of the wind over small and narrow islands, as is the case for St. Thomas and St. Croix, lean to the leeward, so that most of the rain from them falls in the ocean to the lee of the island. Easterly wave passages are important contribu- tors to the rainfall of the Virgin Islands during the months from May through November. Like Puerto Rico, the U. S. Virgin Islands lie in the path of the tropical storms and hurricanes which form over the ocean to the east of the Lesser Antilles. As in Puerto Rico, they are relatively infrequent. While cold frontal passages affect the rainfall regime of the Virgin Islands, the frequency of fronts is less and their intensity is more likely to be diminished and less effective than in Puerto Rico. Annual rainfall values indicate differences in rainfall from location to location with higher elevations generally receiving greater amounts. On St. Thomas and St. John, on the basis of the limited data available, annuaL_averapa__af between 40 _and 60 inches~pear reasor:iable. On St. Croix there is a more noticeable variation from place to place. This Island has the greatest annual rainfall, in excess of 50 inches.in the northwestern corner. There are some indications that stations in a small area along the central portion of the southern coast of St. Croix receive about 40 to 45 inches. A narrow. finger of between 25 and 35 inches extends northeast to southwest over the flatlands south of the hills in the western portion of the Island. Annual rainfall averages less than 30 inches in the eastern end of St. Croix, possibly as low as 20 inches. As in Puerto Rico, there is no sharply defined wet-dry season relation- ship. Records available for the three islands indicate a relatively wet-relatively dry season distribution similar to that found in the southern portion of Puerto Rico. The relatively dry period extends from about December through June. Occasionally, quite heavy rainfall occurs during the so-called drier months. The driest month of St. Thomas and St. John usually is February or March and the wettest month September or October, as in the southern sections of Puerto Rico. On St. Croix, the month with the heaviest rainfall, on the average, ranges from September through November. The number of days with measurable rainfall over the Virgin Islands, based on a few known-to-be reliable stations, ranges from a little less than 200 days annually at the higher rainfall stations to less than 100 days annually at the stations with lowest rainfall. As in Puerto Rico, one of the most striking fea~ures of the temperature regime in the U.S. Virgin Islands is the relatively small variation from the coolest to the warmest months, ranging from about 5° to 7°F. 19 ; UT o,_;J • comfort or discomfort, between economic success or failure, or becween safe and compatible building design can be a delicate one. Through effective planning and intelligent application of climatic considerations co life in the Caribbean, man can truly say he has found his tropical paradise. U. S. VIRGIN ISLANDS Location: The U. S. Virgin Islands are composed of three major islands, together with a number of smaller islands and cays totaling about SO. The three of primary importance are: St. Thomas, where the capital is located; St. Croix, the largest; and St. John, the smallest. These islands follow Vieques Island and Culebra Island in the path of the Lesser Antilles toward South America. St. Thomas lies some 38 miles east of Puerto Rico and about 1,500 miles southeast of New York. St. John lies a few miles east of St. Thomas and St. Croix is located about 40 miles south of St. Thomas and St. John. With an area of about 28 square miles, St. Thomas is the second largest of the U. S. Virgin Islands. This island lies between latitudes 18°23'N and l8°18'N and longitudes 65°03'W and 64°50'W. It is about 5 miles from its northernmost to its southernmost points and a little more than 12 miles from its eastern to western extremities. The smallest of the three principal islands is St. John, with an area af only about 20 square miles. It is also the least populated. St. John lies between latitudes 18°23'N and 18°18'N, and longitudes 64°48'W and 64°40'W. This island extends about 5 miles from its northern to southern- tips and about 8 miles from its easternmost to westernmost points. Somewhat apart from the others, the largest of the three islands is St. Croix which has an area of 84 square miles. It lies between lati- tudes 17°47'N and 17°4l'N, and longitudes 64°54'W and 64°34'W. The Island extends some 19 miles from east to west and 6 miles from north to south. Topography: S!_._Thomaa..llaa.....a.p ~~~mely irregular coastline and is very hilly with practically no flatland. Tfui71ignest hills are generally found near th~ center of the Island, with Crown Mountain at 1,550 feet the highest point. The Island is relatively small and many of the peaks rise above 1,000 feet. Ibis results in rather steep slopes over all the island, so that rainfall runoff is quite _r_~pid and_there are_no per- m.llnent streern• or tTfiff.-- Like St. Thomas, St. John has an extremely irregular shoreline and a very hilly topography. It has a number of peaks over 1,000 feet, topped by Bordeaux Mountain at 1,297 feet in the eastern portion of the island. Slopes are quite steep over all of the island, and there are very few areas of flatland. There are no permanent rivers or creeks. 17 ·1 IJ i , - St. Croix is the largest of the three U. S. Virgin Islands, The topog- raphy is somewhat different from the other two with a broad expanse of low, relatively flatland running along the southern two-thirds of the Island. A range of hills, ranging in elevation from about 500 feet to more than l,000 feet, .topped by Mount Eagle at 1,165 feet, runs along the northern coast. In the eastern end of St. Croix is found another group of slightly lower hills with a maximum elevation of about 860 feet. The relatively small area covered by hills on St. Croix results in rather steep slopes down to the Caribbean in the north and to the level areas to the south. Agriculture is not as important in the U. S. Virgin Islands as it is in Puerto Rico. St. Croix is the only one of the U. s. Virgin Islands with any sizable expanse of flatland suitable for farming, Here sugar cane, which was the principal crop, has been abandoned. Subsistence crops are now a minor effort. Some cattle are raised for milk and meat. In St. Croix, industrial growth has become a significant factor in the island's economy. With the downgrading of agriculture, industrial complexes have been expanded to include the petrochemical industry and refinement of aluminum. Light industrial plants and the manufacture of rum are the other industrial activities in St. Croix and St. Thomas, St, John has no industrial development and remains primarily a National Park. Tourism is the biggest factor in the Virgin Islands economy. It has, over the past years, undergone a vast increase in the numbers of cruise ships, especially at St. Thomas and St. Croix. Hotel facilities have been increased on both islands. One of the principal causes of concern in the U.S. Virgin Islands is the short supply of water. Rainfall, while above 40 inches annually over most of the area, is insufficient. This is due partially to a high evaporation rate and the rapid runoff from the steep slopes on St. Thomas and St. John and, to a certain extent, on St. Croix. In an effort to utilize available water efficiently, most homes and -. business establishments catch rainwater on the roofs and pipe it to cisterns. The runway at the airport at St. Thomas is also used as a catchment area. On St. Thomas and St. John it is co1111110n to see the entire side of a hill cemented to act as a catchment area. Generally, during the drier portion of the year, it is necessary to carry water by barge from Puerto Rico. Installation of a sea-water distillation unit 1 1 on St. Thomas and St. Croix has helped alleviate the water shortage but water still remains a significant factor in the development of the island's economy. ___.. Rainfall in the U.S. Virgin Islands is of the same nature as that in Puerto Rico, falling most frequently in the form of brief showers. The rainfall-producing mechanisms are essentially the same as in Puerto Rico except in the matter of degree. 18 ! : .... 1 / REFERENCE NO. 6 TAT-02-P-04642 TOTO WELL SITE POTABLE WATER ALTERNATIVES REPORT ANNA'S RETREAT, ST. THOMAS, U.S. VIRGI.H ISLANDS Prepared For: carlos !. O'Neill, P.E. osc Luis•· Santos, osc Air and Razardoua Substance Staff Caribbean Field Office o.s. IPA, Region II Santurc:e, Puerto Rico and Bruce Sprague, Chief Incident Reaponae and Prevention Section o.s. DA, Region II Edison, Wev Jersey 08837 Prepared By: Rodolfo Hafner, TAT II J- Kantreda, TAT II Region II Technical Aaaiatance Te- •••ton/SPD Division Edison, Kev Jersey 08137 December 1988 " .... ,.·····: ,·· .. ,: .. / , .. appear to be sufficient land available to increase the cistern voluaes laterally. The only way the volW1e could be increased is by aaking deeper cisterns. This operation would require the shoring of the existing hoaes and apartments, therefore, the possibilty of structural daaage to th••• residences. 2.0 SITE DESCRIPTION NU2 CQBPITIQMS 2.1 sit• Background anc:1 conditions Th• TUtu Well site is located at the eastern end of the Island at the Anna's Retreat Section of St. Thomas (see Figure 2-1 page 5). Most ot the wells are used tor public drinking water supply. The wells appear to be drilled into the TUrpentine Run aquifer. On, or about July 7, 1917, Mr. Irie Tillett, contacted the o.s. Virgin Islands (O.s.v.I.) Deparcaent ot Planning and Natural Resources (DP!fR) regarding an odor eaanating froa the raw well water on his property located at Anna's Retreat, st. Thoaas, o.s.v.I. On July 16, 1987, the OSIPA received a request froa the DP!fR in St. Thoaas, tor aaapling and analyses of several wells in TUtu. on-July 21, th• USIPA and its Technical Assistance T- (TAT) contractor, Roy P. Wuton, Inc., aobilized to st. Thous, to pertona aaaplinq on th• drinJd.nC) water wells auspected of being contaainated. Th••• wells were also reported to have a strong, unpleasant odor and were found to be contaainated with hazardous sul)stances. The IPA and its Technical Assistance T•- (TAT) in coordination with DPIIR, initiated aaapling of wells in the affected area in July 1987. Tb• tut results shoved the presence of high concentrations of gasoline and chlorinated organic caapounda. Pour wells: Elgin, Four Winds, RartbJlan, and Virgin I ■lands Housing Authority (VIBA) ware closed dovn by order of DPNR due to high voe concentrations. Several of the wells in this area are major co-•rcial well service• used tor public drinking water supply, therefore, the incident was classified as major, and the DPlfR co-issioner requested the EPA to as■Wle th• role of Lead Agency. The well locations can be seen in Figure 2-2 page,. A Texaco station, located opposite th• Tillet Well, is suspected as a po■sibla source of contamination. A Petrotight test conducted on the underground storage tanks at this facility indicated leaks in two ot the three tanks. Th••• failures aay have contributed 4 j i.._i ! l .. : fa.wacil.1,..WIIIIIOirt -.,"Dc..c.c..--•> 1 1 r-..J80llla . ..,..,.;nnL 1ac..c..o,._...Gm •- 'ac.. _., ...,..,.. • '1bwalac, lftlm& 1M&. t9' , ... O'MZILL TAT,_ R. BAFNZJl I! .. : i l )!._Ji. t ,, I ' ' - - ) \ NO. WE!.L N .A.\!E NO. 1 BRY~"(S 1 • • -· • WL'IDS 1 z 10DIIIC1'JES t • ., " WINDS 2 3..1 B.\r.11M.Ufl.UDY 13.J 'IIILL 1 ' u &l.lt'!'mUN 8.LIERY 13.2 vuuz i ~ a.umDuH IAIDY 13.3 '1111.l 3 I '-1 C:Dfl ECUN 1 12., 'IIILL ' u C:DIE ICUN 2 1' ~IA UDKUID '-!l C:E:fE £CUN 3 !5 DDUTII 5 !Uavr."S !I DDCS ' ! a ~"S :~.l DEYCOH 1 I , W.LTBUS'S 1-., DEVC0N Z ·- I !Mffll'S 1":'.3 DE'IC:)N 3 • FII.UfQIS 11 DEDI I 10 '1U.tffS 11 LOcn&aT 11 tUWSEY"S _RED BOOK FR!NClDilNS 3AY • (' .. to the groundwater pollution problem, resulting in the contamination of nearby wells. Another suspected source of contamination is the TUtu Esso gas station. This facility stores waste oil in an underground storage tanJc. The facility has had proble■s in the past with leakage fro■ their underground gasoline atorage tank and i• auapec:ted ot using aolventa in the ■-chanic shop. At th• tiae of inspection, the nature of th• probl- bad not been datu-.ined. Botb the Texaco and Esso gas station• are upqradient fro■ the affected vell• vbicb are being supplied vith vater. EPA continued its efforts towards the identification of; affected wells in the area, cuato■ars vbicb bad received water fro■ c:ontaainated wells, and poasible alternate water suppl!•• and re■edial action alternatives. A testing progra■ of wells located outside of the known area of contamination was conducted to evaluate tho•• areas as possible alternate vater supply sources. Sampling of cisterns served by the contuainated wells was also performed. EPA directed th• Ellergency Response Cleanup Services contractor (ERCS) to; clean and disinfect th• five (5) cistarna vbicb bad teated positive for PCZ, aodity the axiating boaa plmlbincJ, di•connect th• contaainated vella, and diapo•• ot th• c:ontaainated vatar. At EPA'• direction, ERCS also contracted a local water bauler to deliver unconta■inated drinking water to tba cisterns by tank truck. A vell sampling progr- va• established by tba EPA to aonitor the valls at the TUtu site tor a one year period. Kin• potential responsible parties bave bean identified. Th••• facilities included thr- 9aaolin• service stations, two vehicle ■aintenance repair shops, tvo territorial governaent aCJ911Ciu, one dry cleaner and one abandoned 9asolin• service atation. EPA has identified Texaco a■ a viable potentially re■pon■ibl• party, based on the results of a aoil/gaa survey conducted on the Texaco Property under order fro• DPNR and under the supervision of EPA. Th• survey found total hydrocarbon concentration• up to 690 ppm of benzene. EPA is continuing its efforts to identify potential responsible parties. 2.2 Topoqraphy and c;eo1ogyill •st. Tho■as is the ac,at northveat island of the o.s. Virgin Islands and the second largest. Tile island is approxiaately 14 ■ilea long and 2 to 3 ■il .. wide and has an area ot 32 square ■il••· i UT iii°; 1 .. 0::>'H .l 7 .. £' .. The land surface is almost entirely sloping and extenc seaward fro■ a central ridge, 800 to 1,200 teet high, running the length of the island. Th• slopes, which co-only exceed 35 degrees, are dissected by nWDerous stream courses of steep gradient. The general appearance i• a panoraaa of steep interstrea■ spurs an rounded peaks. Flat inland is confined to the Olarlotte Aaalie area and a fev -11 alluvial-filled eabayaents. 'l'be only variation in the general topography is in the upper valley of TUrpe.ntine Run in eastern St. Thoaaa. 'l'be valley ha• relatively gentle topography consisting of rolling bill• in a basin surrounded by steep slope• and abarp ridgea. The TUtu Fonaation, th• youngest roc:Jt exposed on st. 'l'boaaa is coaposed alJ10at entirely of angular debris derived fro• the Louisenhoj Formation (an older volcanic fonaation) and ainor lilleatone debris fro■ thin limestone deposited cont-poraneously with the TUtu Formation. 'l'be roc:ts were subsequently tilted to for■ a northward- dipping ho■ocline. Dips rang• fro■ 15 to 90 degrees and average about 50 degrees. Loc:ally the for11Ations are overturned. Tb• ~l• zones that tile- rocb once -y have bad after depoaition have been destroyed by -taaorpbi- or by deposition of ainerals in pore apacea. Groundwater aov ... nt ia nov li■ited to openincJ• along joints and fault zon••· Tb• boaoclinal structure is cut by -ta of faults trending If 45•w, If 55•g and north. Thr- well-defined joint sets parallel each of the major fault directions. Tb• valleys of the island have ai.Jailar trends and are apparently the result of selective erosion of rock weakened by faulting and jointing. Priae zone• of groundVater availability, therefore, follow the valleys. S..11 alluvial deposits ranging froa Pleiatocene to Holocene in age, lie in the valley of TUrpentine Run in east-central St. Tho■aa and the larger coastal eabayaents. Tb• alluviWll of Turpentine Run lies in a narrow band ••ldoa aore than 200 feet in width along the strea■• Naximm thicJtn-• of the alluviua is about 40 f-t. No■t of th• alluviu■, vhicb i• ccmpo■ed of silt, fine sand, and clay and containa discontinuous beds of sand and gravel 2 to 3 feet thick; lies in the Nt. Zion-TUtu area of the upper basin and in the narrow valley fro■ Mariendal to Mangrove Lagoon in the lover basin. Tb• alluviWI extends out under the lagoon n-r the ■outb of Turpentine Run. Although coaposed predo■inately ot tine-grained material, the alluviua readily infiltrate• 8 streamtlow when the groundwater level is below the base of the stream. As such, the alluviWll terms a readily rechargeable aquifer, although it is of small extant and yield. Soae coastal Ulbayaant• beaded by intar.ittant atrem contain ... 11 d•po•ita of alluvbm •illilar to that of Turpentine Run. Maxilnm thicJcn••• of tb- deposit• i• estaated to ba 50 feat, and their areal extant ••ldoa is greater than a few acres (an exception being the Long Bay and Airport area• near Charlotta AJlalia). Near the sea, the alluviua interfinqars vith calcareous sand and at tiaas containa lenses of IIIIDCJrOY• svaap deposits. Therefore, the deposits(!fe ot •inor significance as sources of vatar•. 2.J Rainfa11.Ll.l "Rain is the only natural source of fresh water to replenish the water resources of the island. Rainfa] is seasonal, with a rainy season in late sU111Nr and early tall and a secondary vat season usually in Nay. Nearly halt the rain falls during Auquat-Novuabar. Jt&!ns exceeding l inch inf! e::r: c= •!: ~= 1::." tin• a ~•ar. :t"OPr to 1 • - -8-- . C -- n __ J __ _ __ A hour per¼:: N>9Yt once every 2 y:trs in large 1taraw, n- ra can occur In any 110n , bat an aora lib during the hurricane -ac,n (AIMJUR-Woveaber). About so hrcent of the tiaa anng•l rat.nt•ll 1• batvHn 40 50 en•. Lii• thin 10 percent of the tlie annaa1 rilnfall i• under 35 incbu, vbich usually wna a 11ajor deficiency during the nonaal vat ••••on and drought. Th• CUJ1Ulative departure froa average and the 10-y-r running average ot rainfall sbova that at this tiaa of writing (1967) the island .. Y be entering a period of deficient rainfall. With the exception of a fev years in the late 1940'• and early 1950'•, rainfall in th• past 30 years bas bean balov average. There ha• bean a long-ter11 decline of about 10 inch•• in annual rainfall •inc• the peak ot the surplu• rainfall period in the early 1930'•· The aoat aavara droughts on record ~curred in 1964 and 1967, when only 27 and 24 inches -~ rain tell, respectively. &raal distribution of long-tar. rainfall, i• controlled by topography and the prevailing easterly to northeasterly wind■• Bov•var, individual atorma -y or aay not show the effects of orographic control or prevailing winds and the araalc~fstribution of the atorma can ba very irregular•. S•• Figure 2-3, page 10, tor average yearly rainfall. 9 - -- 2.4 sampling Results Th• TUtu v•ll sit• has be•n saapled repeatedly over· tb• last ten aonths and found to contain definite contaaination. Th• initial ••••• .. •nt va• conducted in July through S•pteaber of 1987. Sub•equent saapling and analysis ha• proceeded on a 110ntbly basis. Tb• initial •••••■-nt conaid•red 26 w•ll• and approxillat•ly 50 ci•t•rna. Of tb- well• and cisterns: 24 w•ll• and 5 ci•t•rna w•r• found to be contaainated. Tb• 5 ci•t•rna vere cl•aned and di•intected by th• DCS contractor. Sub•equent 110nitoring ha• be•n conaid•red for th• 24 wells that shoved soa• type of contaaination. Ta!:,le 2-1 pg. 12, li•t• the wells included in th• current 8U1pling prograa. Ta!:,le• 2-2 and 2-3, pages 13-16, •hov the volatil• organic analy•i• re•ults of th• contaminated v•lls and giv• the bigh•st conc•ntration of organic contaaination found during th• last six 110nth•. The sampling, and ■oat of th• preli•inary Photovac porta!:,le GC •creening, vas conducted by the U.S. EPA Region II TAT. Drinking water laboratories have perforaed foraal analy••• to verity the photovac acreeninq reaulta and to cover tbe entire spectr1m of poaaibl• baaardoaa contaainanta. AlthOUCJb, tbe concentration of th- contaainanta fluctuat•• aontbly, it ia noteworthy tbat tba -jor contaainants hav• be•n 1,2-trana-dicbloroethyl•n• (DCE), trichloroethylena (TCZ), t•trachloroathylen• (PCZ), toluene (TOL), benzene (BD), tart.butyl .. thyl ether (TBIIE) and various .. tals. Their high concentration in four wells; Tillet, &arvey, SJlitb and Steal• bas bean evident fZ'OII tb• initial ass•ssaant. Tb••• well• show concantrationa of volatil• organica (VO) in ezcua of 1,000 ppb. Th• -jor and 110st conai•tant contuainant appaan to be PCS. Th• Till•t vell ha• also shovn vary high DCB and BD contuaination. Pour oth•r v•ll•: Prancoi•, Mathia•, laar Winda, and Elgin: var• confiriaed to hav• >50 ppb -~. ··Th• last confirmation analysis conducted during octob•r 1917, included the entire Baaardoua Substanc• Liat (BSL), (consisting of approxiaately 150 cb-icals). At that tille, significant levels of '1'IIIE up to 470 ppb, and ••thyl•n• chloride up to 120,000 ppb ver• detected. So•• suapl•• have also shown traces of vinyl chloride, chlorofona, 1,1,1-tricbloroethana, broaaclichloroethane, xylene, and •tbylbenzene. Pinally, the BSL analysis also shoved the pr•••nc• of \ \ ... \: '· :-- .' \ 11 - -- TABLE 2-1 CURRENT WELL MONITORING PROGRAM AND CLASSIFICATION AT TU'l'tJ WELL SITE WELL MAU CLASSIFICATION OPEN/CLOSED 1. Dede Public Open 2. Steele Private Cloaed 3. Elgin fl coaa.rcial Cloaed Elgin 12 COlalercial Closed Elgin fl co-rcial Closed 4. Pour Winda co.aercial Closed 5. S.itb Private Closed 6. Bryan co-ercial Open 7. Harvey Private Closed a. Tillat c~rcial Closed 9. Bartbllan Estate Private Closed 10. Devcon fl Cowrcial Open Devcon fl Coaaercial Open 11. VDIA fl Inatitutional Closed VDIA 13 Inatitutional Closed 12. Dench Coaaercial Pmlp/No 13. Raasey Private Open 14. Bartbllan Crusher Coaaercial Closed 15. Alpha Leonard Private Open 16. Francois Private Open 17. Daaitris Cowrcial Open 11. Rodrigue& AUto Private Open 19. llarthllan Bakery Cowrcial Cloaed 20. Jfathiu Private Open ' Definition of Claaaificationa Private: Wells which serve one or tvo boua-. Power co-ercial: Well• that are uaecl to yield water for sale. Inatitutional: Well• owned and operated by a non-profit inatitution or governaantal agency. Public: Well• that are tor pw:,lic uae. 12 --- REFERENCE NO. 7 ... '-I NUS CORPORATION TELECON NOTE] CONTIIIOI. NO: OATI: TIMI: 3/3/~q I (L(J OISTIUIUTION: U1<;ZI C "l <?9D t. 2. C, IITWIIN: OP: IIIMONI: -ta Wo..---<-,_., Sc~\ rl-\' f> r E(>lr - Gw M7~. (212 )2.~4-lrl?L( AND: !NUii OtSCUSSION: -~ • ·, .· : , .. , ... y .,: .. ,::.CJ .. · --··1·•.·rr~~·1"')11·'j!/"~,,R. 'IC· "". · URFJ\C1'" o· f T~E'- ' 'r !le . ii 1" IM' 'P j • 'ii ' "!' · ,• I ' · .-" I "' ! 1,-,.~ i. Ji'jjf,u ' - 1)J , 'J}t,.,,_ · 1 ,a - 7_ 1'. 'J-'t :1, f' ri~ ·r· 1 r, ~~ ~ :ij_ , J\l ·B -- ~ s-1 ~ ,, o. ·- u • f .. ~-n .1 11~- " , r ,,• , )1 r , i· , . , ~ "· , I ,,, . , , /4- c. '~ ii · ~ ~ 1 . la , ', ::;;;;:::~Sf ?I s r. ·~-: ., . ,,,,, . --'-•~' __ ·, ~-·--,~- · ·-·-~·- ' . . , _: . £ Pro~~rnd in tuoperaliun with !he \'.~. [l!VlflUNl)lEilTl\l. PROTE'CT!OM AGEMCY U!ilTElJ STATES EEULOGlC/\L SURVEY \Ji ATF.H· !lESOUHCES lllVEST!G.Jl TlONS REPOflT 8il-li 'l 3 I 1988 PO'.!.'ENTIOlvIE'.rRIC SURF ACE. OF THE 'rURPENTINE RUN BASIN AQUIFER IN 'l'H.E TUTU AREA, !~ASTERN ST. THOMAS, U.S. VIRGIN ISLANDS, SEPTEIV1BER 11, 1987 By Rebert P~ G:rave.s and Ralph Gonzii.lez Ground -water levels in the Tu-rponti ne Eun basin aqu i fer, in eastern C' ,_, Thomes ., wert! mrc>.asured in 32 \.'c. 1.1s on Se_ptcmbe.r 11, 1987 and a po1~e_'1t::icrn::;t-rie ~; 1.1rfac e map 1.vas prC>.parecl. TJ1e altitude of ull wells was .::-c~f,:=:-roncecl to l~r:,.:-wn land ;;urfar:e o.:'..ti t.ude. '.Jenchmarks by Les e. oi a J.e.vel _,."urvsy inst rw11eni: . The putentiome.tric .surface map wa:~ prepared by the U . S . Ceo l ogical SurvCc.~.Y in cooperat ion wi th the U. S . Envi r onmental ProtJ-'.C l.:.~on Agt::.ncy . . 1:·:::::-c=.c=.L~ro ::'. vc•:'..c.an -i.c: rock s underlie '.furpen tine Ru.n bac.,in and are ~-cca_i_ly over .Lain by 21li..t\':i.al de posits (Donnelly, 1959), The alluvial d2.posits can range to 40 feet in thickness, Ground water in the '.f\i·cpe11i::i.ne .Run basin occurs in the fra ctured vol c2nic r.-ock an d alluvial .J,c:pu~~i1:s und"r ',.;a ter - t0hle condii_ ion:,; (Jo-::-c'.an, 1973) , 'l'Le al luvi~,1 1•1.,_,p:::,::;:i_ ;,.f; a n:! cu:1:c;j.de.red to be hydraulical .Ly connected wiUi the :fractured ' <.·o.Lc,mi c re ek. 'vi'e.11 c: e,pti1s in the bas in can ·::-ang e fr.-cm 55 to 325 :feet ~0lti w land surface . ,:;2.v2raJ. WE' I_ :.s l'te.re. be.:.ng P'~ur:pcd, or pw:cping had j 1.1st t e:c:ninate.d, ,,/..,_c,n ":he •,;a ::-.<? [ .: Pve.lc; ·we.::,::. mea'..>'..rcc.d ( ta "c:i.le. L), ':hese wat.er levels :·(; i c ct a pc.uP.J_ci ng c t re,_:uvery conciition; therefor e. , st.<.J.t·ic wate.r- J.Rvel c::-nditions thr.-oughout. the Turpen tine Run bas i n at th<", t i me of IrH~a.su.rernent. ::~inn('!: be as:;i..-:mcd . t\dciiti u:1 a_·_ ~nfor:mation abo·~lt grcund-wa l.r-:r l evels in the are2 of .";tudy i s ava_Llab :Le. from the U.S. Geo logical S1_rrvey, 1r/aC.er Res01..crces '.) :~1_,:i_:c;i (~'~! , C;Jc. i Ubean District o:ffiee in San. Juan 1 Puect.o Rico , Tel. (309) 7,W •" t,3t,;J . SELECTED REFERENCES 'Jccinelly , T . W,, 1959 , Geology of St. Thom.c1 ~, and St . J ohn, Virgin l.slands: Ucip-...1b lisf'..ed Ph .D. dissertat.i.on, ~r in cr..;tur~ University, 1/9 p. Gc! ragh ty & Mil J.er , Inc ., 1983 , .Report on cu.rrent groltnd water conditions :Ln t he U. S . Virgin Islands : Prepared for t he gove r nmen t of t he U.S . ','i::gi11 L;::.and s Dr2~Ja.rtmen t uf Cunservat:~on a::1d C1_di::.LE"a l Affa irs, 80 p. Jo nlan , D, G, and Cosner , 0 . J . 1 197 3, A survey of the water resources of St . Thomas ~ Virgi n Ts lands : U.S. G(~o'.i.ogical Survey open-file r.-e_p,Jrt., 55 p . Stevc~s, K.E., G6~ez-c;6mez, F. , and Ali cea , J,, 1981 , Water wells in the U. ~: . Virgin Islan(b , Pt. 1 , St. Thoma .s: U.S. Geological Survey Open-File Report 82- 82. • • 1: hL SURVEY .: ._HCE -'3 0 /VlSION - Table 1. Description of wel!s and September 11, 1987 waterdle'lel measurements in Turpentine Run /Jasin, SL Thom.as, U. S Virgin Islands P,cp.Qrod In coopemtion with the U.S. l:'l,NWl;(X4tAEITTAL PROT~CT10N ,\GENCY [Dulum is moa n sea !evel. Abbreviations: hyphens, data not available; (RL), suspoc~ed .ocovorlng leve l; (PL), su8pected pumping !svoQ - ----,-·---- Vlen Well number identification number ' I 01 18 202110 tiLf5 35 80'.J 02 132026064535800 03 182025064535800 Ol, 1820 HIIJ64535900 OJ 182017064535900 06 I ~ 82016 06/1 ~ 35900 07 18201 C'. 06.'.i5 400QO 08 I 182015061,51, 0000 09 1820112061,5]3400 l ll ! 182037061+53 1100 11 182033061:531200 12 182QL,8Q6453 1Lf00 1] 18201,9064530900 ll+ 132 02 906!,5 31500 :s 182027064531 80 0 16 182027061153 1900 17 d l 320200611532000 13 }_ 8202 C 06L,5 3190 0 19 lll201906t,53 l 900 · 20 132016064532000 21 182017 06,~532200 22 182021064532500 23 I 182018064532800 24 1820170611533000 25 182018064533100 26 182018 061153 3200 27 1820190645]3300 23 182015061+5327 00 29 182016064532900 JD 1820150 61+5 33 DO '.l :n 18201'10611532900 ]2 1820 l 20611531 l100 33 l 8 20090 61,SJ l JOO 3!+ 18200806ft 531 !+OD JS 181943061,525300 ' 36 1819!100 611525200 37 1819JR01i4525100 38 1819J806L,525000 !'' 39 13193 7 0611524900 40 l-8 ·i. ':;: J.S864S2.1,.'.1CV 41 1819 2106/;.)2 41 00 Well n8.me ~ario B-!:yan ',ell ,'t l 1/ ·- :lar io B-:::van liell l/2 Ma-:-io Bryan rl'iell f.!3 Lockhart Well II 1 Loclch;irt Well I! 7. Lockh2.~':. \~e_ ),:'t_ f,f] Lock'.10,rt Well i/4 Lockhart Well ii 5 Demi t ry Well VIH.A Well /11 VIHA Well fl2 VIHA Well ft3 VIHA Well /1 !1 Tillets well four Winds Plaza well ii l Four Wi:nd.s Pl aza well 'IO It•- Gene Egli~l 1,.,'ell ff l Gene Eglin Well i/2 Gene Egl in Well 1/3 E. Steel well Osborn Hn,rvey Crusho.r \,,1e :_1 Bakery Well Creger Motors Well II 1 Creger Motors Well //2 Creger Motors Well //3 Creger Motors Well t/4 E 1 s & A Corp Well ff l E' s & A Corp Well /,12 E 1 s ,, A Corp r - -1 1 {'le_ .. _, iJJ E 1 s & A Corp Well //4 .Fr ancois La Place L. Smith Matthias Farrington well Poly Carib/Devcon lll Poly Carib/Devcon f/2 Poly_ .Cadb/D e v.con Ii] Poly Carib/Devcon /J4 'f\.1 Ll· .l.c. ·· ·we ~-~/::}1.d. :L -,fri:L l (Gov . of t he Virgin Islands) Dept. of Agriculture Animal Shelter ' I Depth Depth V:/a.ter level V/o.ter Land Yev.r of of below land Ievel surf nee drilled well caaing Construction surface altitude altitude (feet) (foet) (feet) (feet) (feet) }978 140 -- --- -- - - --- 215 -· --- - - - -- 11 209 220 ---- - - -- - - ---- - 10 n r~ c, L ·v CJ 218 - - -- - - - - - ----- 09 un 192 - -- -· - - - - - 08 184 192 ---- - -- - - ----- OS 18] 188 -- - - - -- - - ----- 06 183 189 - - - - -- - - - ---- - 08 - -- - - - - - -- -- ·- - - ---- - 80 lSl(RL) 231 1977 17.5 11 l Open ho~e 56 175 2Jl 1977 150 37 Open hole 60 175 2 35 1978 142 73 Open hole 17 2n 239 1978 140 ' 69 Open hole 39 239 278 ---- 100 15 Open hole 21 165 186 ' ---- 300 - - -- - - - 13 153 ' 166 1981 285 36 Open ho.Le 09 156 165 ---- 225 - - ----- 12 ~32 ! 144 --- - 225 - - - -- -- 37 l l2(RL) 149 ---- --- - - ----- 66 86(RL) 152 1950's 105 -- --- - - 7 6- 99(RL) 175- 1978 160 -- ---- - 30 108 138 1978 210 ·-·- I Open hole 32 108 140 1978 325 36 Open hole 22 108 130 ---- - - - -- ·--- -- 27 108 135 ---- - - - - - ----- 26 109 135 21 116 137 20 128 148 123 l8 108 126 19 107 126 16 109 125 28 83 111 196D's 10 80 90 1960 1 s 55 10 80 90 1J 30 43 .. 0 -83(PL) 35 .L .LO Lo () ]_ ; . _, 04 cs 9 65"00' 05°06' 64"55' 04<>50' 1W26'r--------------~ -"',-'~------------~.,=....,,,---- -------~-'T'~----~ ·O \) 18°20'- 1.a<'17'~-------------~-- --------- - --~----- ----- ----'------_j 3(206) -- I/lap of St. Thomas showing the study area. EXPLANATION POTENTIOMETRIC CONTOUR - Shows altiti.t-de of water tabte !n feet. Dashod wh ere approx.lmatoly located. Quoriod (?) where location ls uncertain. Contour Interval varlubie. Datum in mo an sea lev<JL WATER-LEVEL DATA CONTROL POINT - Op6n nurnber is the wolf number shown on tabto 1. Number in parentheses ts tt1'8 n!iitude of water lovo! in feo t. Datum is mean sea level, •--- ., " _,_ BAS!N BOUNDl1RY -------------·--------------------------- ----------------------------- ------ ··---- ------------------------------~ ------- CARl8BEAN DIST SAN .JJAN, PU€RTO I • REFERENCE NO. 9 Uncontrolled Hazardous Waste Site Ranking System A Users Manual (HW-10) Originally Published in the July 18, 1982, Federal Register United States Environmental Protection Agency - 1984 - -- - TAIi.i 2 nmaMILITt or GIOLOGIC NATDUU• Type of Material ClaJ, c-,.ct till, 1llale; uafnctuM .. ,_r,blc ... 1...-. roca Silt, loeee, 1lltJ claye, 1llt7 loaaa, claJ loaa; lH• ,. ... 111. 11.M•to•, dolalt••• a .. u•eto•; aolleratelJ pemull1• till Pl• .... a• elltJ .... , .... , loaa; loaa, ..... , _..ratelJ ,. .... ~ 11-etoae, dolaalt••• a• ... ac .. <• kant) i _..ratelJ fractaM 1...-. a• •t-r,ldc l'OCU, .... coane till Crawl, .... , 11111111 fractuM 11aeoua a .. •t-rpblc rocu; pemee~ liualt ... lawe; kant 11.MatOM a .. dolaalte *Deri ... fc.1 Appl'Oaiaat• la•• of lydralllic rA•uct1nt7 Aaai&DN Val• 0 l 2 l Dane, S. I., r.seutl.ir r. ... "!1!t°' lltml llaeeriale la n .... 'lllroaall r.nue lfNla, I.J.M. et ... , Ac c "-•• In forii, iRi frN•• I.A. a• J.A. Cllersy, GNiiallwtH'• Preatlc.-llall, lac., ... Tork. 1979 -· .Aa REFERENCE NO. 10 '-,,·': ·' •' .· ··,:, -, .l 1 ,, .J ., ., '! ,, I l t The Geological Society of America Memoir 98 CARIBBEAN GEOLOGICAL INVESTIGATIONS By H. H. !i,ea. £dill, a-,,_ a.a,,, Pri..,_ u..,,-,. f'ri• en, N• J,-, Cad 0. Bowin Woou Hou O~-,- TvtiMi-, WINI H-, Marwlrudu Thoma W. Donnelly !Ap,. a.a,,, Ria Uru,rti'1, H_,,., T111a John T. Wheaen n,,,. C.0Uf1 atl O,--,rapl,J, U,u,tiJy ,f w--,,-.SMUU, w---, ... E. R. Oxburgb 0-p,. C.ohf, ati Muw,aur,, 011/•• u,,;,,.n,,, Oxf••· E,.,lctti . ., . - -J..;. t . . I ... ., ! • l; ,. ► i ,., •,: .~ r, •"".... r- - '·-· I-{ ,- ,- - _.__... 9~ CAalHUN ClOLOGICAL INVUTICATIONI the final b.:ue map, hnc good shore-line detail. Mappins on Sa. John was Jone on I :20,000 cnl.argcmcnas of the I :40.000 U.S. C-oas& and Geodetic Survey map. Aerial phoaocraphs ol approximately I : 50,000 scale were UIC· lul lor aomc Hrucaural inaerpreaationa. Exposures along the 1hore lines ranged in quality lrom excellent to nry poor. Tho1e inland. cxccp& in recent road cuts, were almost invariably very poor. The bcH outc1··•••· Thoma• and Sa. John arc 11ecp clilfs. whic.h arc in placca . _'Jravcnc. More shcl1crcd alaorc linn .uc u1ily walkc1I, Lua rock .· . · arc much poorer. l.aboracory i11vc11iga1ioa1 uidt •lldy of aenral hundred 1hin aeclions. X-ray dillr;il"lion cxamin;ation of ,wk taaplcs and mincr;al aep;araccs, about 500 partio1l chc111ic.il analyKI. imcl n11t11trou1 mineral dc1ermina1ions b)· opaical cuminaaion of crwlacd umpla. About a du1cn feldspars were dcacrmincd by measurcmc:na of index of rcfracaion of pains orienacd on the univcrul stage. according lo ahe mcahod of Smith (1960). Approxim,uely 100 additional pbgioclasc aamplcs were dc1cnnincd by musuremcnts of indicts of rehac&ion of unoricnacd grains. An cx&cnsivc optical sandy of ahc feldspars, compleacd ahcr 1hi1 manuscripa wa1 firs& 111bmiucJ, has been publi,hcd cbcwhcrc (Donnelly, 1!165). Pyroxcnn were deacnnincJ by mcaa• urcmcnt of ra, and 2V, according 10 the mcahod ol Hes• (1949). SUMMARY OF STRATIGRAPHY OF ST. THOMAS AND ST.JOHN The rod. uniu of Sa. Thomaa and Sa. John (fie. 2) can be divided into three major poup1: ahe Water bland Formation, which comisas of ker.a- aophyrcs and 1pili1c1; the Virgin bland Group, which consi111 of anJcsitic pyroclastic rod.a and icdimcnu; and one or more dioriaic pluaons. TI,e Water bland Formation possibly is late Lower Crc1auou1. n,c Virgin Island Group i, proLably Albian (although ahc Hans Lollik formation could be Eocene), and the diori1a arc orly Tertiary. The oltk11 rocb in 1he Virgin blanth arc ahe kera1ophyrc1 and 1pili1n ol ahc \\'a1cr bland formation. These volcanic rocb arc prcdoaainandy flows and llow breuiu, but keraaophyric pyrocla11ic rocb arc widespread. A few of ahe finc-araincd aullaccoua bed, contain wcll-pracrvcd lladlolaria of undetermined ace. Noaewonhy in the Water bland Fonn.a&ion ia ahc ab- 1encc of terricenoua icdimenli. Thil characacrilaic, together with their ap- p;arcndy lcncoua mincralocy, has led &he wri1cr 10 1hc conclusion &baa they arc probably volcanic rock, which were extruded on a relatively level ocean lloor, prior 10 die cxi11cnu ol a ncnch or island pla1lorm. In connua 10 the pouula1ed abyssal environment lor the Waler bland volcanic roch. most o( the overlying pyroclastic rocks ol the Virgin Island Group ,~ere c11.nudcd suhacrially. Both ahe volnuic a11J 1cdimc111ary aocks uhibia slump 11ruc1urcs. a11d 10111e mcgab1cccias cont.iin limestone blocks 111110 100 feet long. The bull of the 1c1limcn1ary tocks in 1hc Vi1gin hlanJ ,. I • ....... - - ·~I-·--, i-J.,( -, T. W. PONNlllY-ST. TIIOMAS ANII ~I. JOIIN, 11 S \ IIIC,IN hi At,11~ !J.·, G101~p ar~ cu.use ,vackcs consiuiut; .ilmml cn1i1dy of slil:l11lr IHJlht'l<'d dcbns 1lcrl\'cd lrom 1hc andcsi1ic py1od.1uic roe l.s. The ,kpo,ition ul rhh group may l1a1·c accompanied 1he for111o11io11 of the i11i1i.il ii.I.lull plJtl111 ,11 ,md trench. Q. ::, 0 II: " C 0 a z .Q .. ...J <( en r-• z " Cl) II: ::, > 0 w u <( t-w 0: u COH,O <•r ,o., ,o.,., UHi-i HANS LOLUK FORMATION l•0.000 Itel• I AUGIT(•.U•O(S11( 811lCCI• ••• 'uff U•per ••• •••!' conloch "•' 111n I TUTU FORMATION (6000 l~el •l ltJffACfOUS •&(.I([ ln<ltJdt1 ntor ir,e bou m• Cokl Poinl Megobreccio hlholoc,.e, ,.,., 1h1 ••o ,, •h• Congo Cow L1me51on1 Member 1200- 300 feel). COIIISlLY c11nu1' It,( llM(Slot.[ f•• el lurmo11.-n nul t•"Oltd ,n lJ S, ••l~nJt OUTER BRASS LIMESTOUE 1200 - 600 ltrl I P•UITIILU SILICIFl[O, TUffAClc,us lllO•OL AIIIIN LUllSTONl ' LOUISENHOJ FORMATION (14,000 leel (W SI. Thomosl 4000 IHI IE SI Thoma,) 7000 feel IW SI John) I 1uG1H- •N0Uut i11ccc,a ... TUFF I.LIil' •fAClt al CLCVC I Ntor lho .... la "" Cobn Poinl Conglamerole hlholocies .... p,, ... , eAd , ...... ti WAl(II ISLINO fOIIMAT1ON ...... , ... . UNCONFORMITY WATER ISLAND FORMATION (15,000 feett) KEHrOPMtlll FLOWS, flow 811ECCIIS, ..... TUFfl •1111 IPILIT[ fLDWS OAd Minor IIIOIOLAll11(S • IAl11111,ed 111, d•••• e11d plr.,91 of ll(lf&lOPHYfl( 1-"old!ug ah~•· 1kp?)itio11 ol clic V11i;i11 hl.111J G1011p rnulrul l.,,i;d from Jallc1cn11JI ,·cr11cal 1110,·c111c111 111cl 1•10,l11c • I • • I I I l · II ,llll,ll:C•1psu 11- 1,111; Ing from as· 10 !JO•. Tl1c 3)Sod;1tnl )llil.c )lip (JIIIIS l1.11c lw1i,u111.1I · .. ,;,.,, of IL'U 1ha11 I 1111lc. Ahhorwh w111;10 111ctJ11101 1,111·, t·II . 1 I · I I , • • D <l ) I l'>II 1111!; I 0111 I ll' c?1placc111c111 ol d1ur111c l'hlloll\ ;iJl· cxtcmi,·c, 1he ,~c,cc111 tho iht1J) ol ~, 1 homas and ahe 1ou1hcrn thirJ uf S1. John arc C)SC11tially 1111111,:1., 111.,1 pho)c:,I 'f -, t' :·, ,•. ..... o·•. I-· ¼ n .. ( CARIIICAN ClOLOCICAL IN\'UllCATIONS WATER ISLAND FORMATION CCNHAL STATI.IUCNT The Water hbnd Foraution of pouible late Lower Crc1accou1 age lumim almost entirely of kcratophyre, lf>ilitc, and r.adiolarian 11111. The c>,;- po.ed thicLnc:u of this forsnaaioa ia 15.000 feel, hued on projec1ion of the hii;hesa am.I lo,,cu ho1i101119 •·'l!IIO"ablc conection for lcnticularit)' 111i1;h1 lower 1he u uc thick...,, •. ~ Kction 10 8000 or 10,000 fee,. \\'.11i:r hb11J, in the harbol "1 ...... Amalie. St. Thomas, ha• been ":lcoed as 1he l)JIC locality beca ... ·ol 1hc great variety of rod. 1ypcs 1hcre and 1lae gc:ncr.1I ci.cellcncc of CXp01urc1, although eucllent ex11osures crop 0111 c:111e11,hd)· .. long 1he aouah '11ore1 of Sa. Thomu and S1. John. "Keuaol'h)le", .as useJ here, i1 an extrusive or hypabyual inu1uivc ,·ol- cJnic rod. comiuing prodiminantly of albiac and quaru, wi1h chlori1e. micueou1111ine1.1ls, and iron oxide!i. Nearly all of ahc Virgin bbnds kera&o· ph)rc1 co111ain con>illcublc bee q11.an1, commonly as con1picuo111 phcno- ll)•U. Those ,, i1h ,111o1111 phenocr)US could be called "quaru Lcr.110- f'h)re" bu1 m;my aphani1ic roch here c.allcd "Le1a1ophyrc" are chcmic:111)· iJcnaical 10 1hc ,o ulleJ "quaru Ler.a1ophyres·· and the simpleu aerm· i1 p1t:· fcrrcJ for all 1hesc rocLI. ,\ acriking fcaaurc of kcr;uophyrcs is ahc abw:uce of phenocrysts (or pscudoa1orphs) of pyroxene, amphibolc, and 1nica. K,·ra10- ph)ric Oows anJ Cf)S&;il tuls arc soJic, wi1h a \'Cry low po1aui11111 co111c:111. Lu, M>aoc appare111ly viuic cuffs arc sligluly more 1,01;iuic. Kcr;i1oph)1C iu- uu,i\'C rocb hnc a higher po1auium content an ' commonly co111o1in ,c:,- onJary monoclinic K feldspar. "Spilitc" is a gneni,h w:cmingly aimed u1nuivc or hypaLyu.al inuusi,·c 1uil. comh1ing of chlorite anJ albi1e. wi1h variable amounts of epidou:. p1dini1c, and c.1ld1e. Fresh phcnocry111 of dinopyroi.enc a1e gcncrillly 1ueacn1; amphibolc and olivine were 001 seen in die Virgin Islands spiliacs. ,\m)'gdulcs arc ;ib1111Ja111 ,md commonly comain nwsa of the calcium con- 1cn1 of dac rOlLs .as tpidotc. calci1e, or prchni1e, wida qu:ir11 aud chlo1i1c. Thcac 1pili1e, cont;iin about the ,amc amou111 of N;i10 ill ahc ;111gi1c ;a11dcsi1cs of ahc Louiacnjoj Forma1ion, and i1bo111 O.S per ,cm '!101e d1an Virgin blanJs diabase dikes. Included wiah 1hc •1•ili1cs here is ii pa11i;ally ;ilbi1iaed augi1e andcsi1c which occurs near 1he aop of ahe forma1ion. The name spili1c h:is been applied in ahc pall 10 1nany divcnc rock aypcs. ,omc of "·hiLh may be low-grade regionally me1.amorph~d a11dcai1es 01· basahs. Ocher spililcs appea.- to hnc been unusually hydrou1 RIJfic i11m1- si,·c rocks, and many ,uc dcu1criully altered b,u;ilts or andc1i1c1. llo,vc,·cr, 1hc1c is an impressive boJy of evidence that many socalled 1pili1e1, not;ibly ccuain 01Jovician, Devonian, and Cretaceous geosynclinal 1pili1cs, have chuac&eri11ic.s IMhich can be bcu explained by auuming an csw:mially mag• ma1ic origin for ahesc rocks. h is 10 this lauer group of rock, aha& 1he Water lsl,rnd Forcoo11ion spili1es belong. I ·-, -·- -, --·--, ---, ( Jt 111:'\, 1• , \ lh.1.1, 1 .. 1 ''"" •f, Suda 1pili1i:s 111.1y be 1ho11i;h1 of JS ao, ls hl1id1 h.1,c: fo1111nl I>)' .111,11111 1io11 of andesi1cs. flo,vc,·cr, 1his proceu is believe,! 10 occur d111 i11g a IJ1c: 11age in 1hc solitlific.11io11 of a hydrous mafic magm.1 and is 1101 c,11bc1I hr later mc1amorphism. Gi\'tn a ceruin co111bina1io11 ol phpi,JI anti chc1111i.il conditions, spili1i1a1ion of mafic cxuusi\-e rcxh is 111c:,·i1aLk lle11tc I h,· &crm. applied in an admiueJly rernie1i,c 1;cnc1ic (hrncc suhJnll\i:) st:11>,·, i, ii ll)Cful one and )houl,I be rc1Ji11cJ. Tl1c a111hur a,lmiu 111.11 lu,., g1.11I,· me1amo1phism m.1y 0Lli1t:u1c: 1hc minn aloi;icJI 0111:1 i;i 111:cc:>s,11 y for ,ta .. recoi;11i1ion of spili1i1.11io11. Chemical a11Jl)sis 11( a l.11~i: a111I c;11d11II) scli:ur,I sui1c ol ,pcci1111:m 111ii;h1 1evi:.il ,d1cll11:1 or 1101 &he 11u·1.111111111l11, ro,Ls iu qui:,11011 h.1J l1rr11 urii;inJlly "1'1l11i1nl. L111 ,11d1 .111.11),1> 1111i;111 .,h .. I.iii 10 do so, J111I 1l1c 1c1111 should lu: apj'l11:,I 1,•i1h 1.11 t 111 ,11d1 io, l. sui1n 1-l KA 101'11\ ~U '"'""''" '"'Y J/111,·,,,,,,,. !.,·1.11111,h)IC llllllf'll>I"> .11111111 l,,111 lol1h, 111 ti,, \\';i1n hl,11111 h11111,11iun. td1»1 l.c1.1lllj'l1y1c O(CIII> J> 11111,·, .111,I lluh 1111:u i.,,. ,.,i,h minor 1111ls. Lo&h c1p1.1lli11e ;111,I \·i11i, (1hc l.111n .1h,··•)> dn i11 ilinl) .1111 1_ rardy, n1lt.111it l11c:1Ci:1>. Kr1.11oph)·1 it in1111si, c: "" l., .11 i: 11111 11111 ,11111 114111 . 1hc:y 01u1r a1, l,01h ,lil.n a111I pl11i;,, ,01111111111I) 1,·11h ,·c1y h'< II dnd"I'"' columnar joi111ini;. l-n;11ul'h)1ic lloh·• ;111.: j;l'11t•1.,lly 11:11, o( lnl 111 1h1<l.11n, I ,·h 1111,l 11111-, arc compk1dy n,110,c,I 110111 1op 10 L.11,c:; 1ho1,c ,,·hi, h ;11c h'l'II , , 11111,,·d .,,.. uri .. inc only for 1111:ir 11.:i..1111.,I unif111111i1y. IIJl.ini; Jlld t l11ll111i; 1'111110111,·11., a1c ;1Lsu11. flo,v LJ111lini;. 11w;,lly 1,111111:wh.11 rn111011td. i, sc,·11 1111 .di)· (l'I :1. Iii;. ·I). C:onlJI IS Lt:lh'UII """' 1111i1> JIC (01111110111) d1llic11li 10 idc1111lr ·" such, an,I a11i1utln uf 1l1i: llmv• .11c lllll .1hvJys r.1,ily •"ll'11.,i11nl One 1hicL l.,·r,1111l'l1)1e llmv ur.11 1l1i: L;1se of the )t·,1i,,n, 011 ll.1111 lh.111. SI. John. ,ho,,s 1;ovd lidd .11111 pc11ui;ral'l1ic C\'i,lc:11, e ol ,·t11 ic al tlillu l'IIU.1 lion. The llolV is ;il,0111 HiS ki:1 1hitl, an,I ncJr 1hr ,c111n " 11-,t,h,h c•.i). i;ra1li111; IU£1ct11hhg1ay ,lm\'11wa11I Jll1I 111'"'·•11l. l'l"l111i;1.1phi, d11fn,11tn MIi be di.c11ssc1l l.11cr. Tl1i: ,olor cl1a11i;c ol,,crn·J in 1hc hd,I ,n11dd ;ippe.,1 10 Le 1rb1i:,I lo .• ,lilfnc111i.1I 1lq:1n: 11f oxi,ti1i11n of i111n hllhin 1111· n., .. ,,·hid1 i1, l'roh.1Lly 1d.11nl In 1d.,1iH ,11111l'11l1.11i1111 111 ,11I ,111 0 111 111l' 11,, .. ccmcr during ,oolini;. Kcra1oph)·rc flow b1elci.1,. 01C1111111i; ,1> 1li1,u c1c l,uh, ;11 c 1,111!..11,lr 111.,,. c~mn~on 1ha11 flo,.,s in &he lcr.nopl1)·1c: sc,111encc lm1 a1c ,lillic11h io J1>- un~uish_ f1om flows. ·11,e 111;111ii. of 1hc llow br,·c,i.1, 1,111 linl'lt:lld) 111 1lm~11g11uhcd f10111d1i: l1.1g1111:11h only h) ,.11d11I "" 111i11) 11f 11,c 0111< "'I'; ""· jMIIIIJ of 1vu1h1:1111c ,,hid, lO\'C:IS 111ml lt:1Jlt>pl1)lt:> dh,tiH·I) ubs,111,, 1he fine dc1ail, nc,cb;i1y 10 11:c<>gnizc 1hesc: rods. 1:ugm,·1111, in fluh· l,1nd." a1e ,11ba11gula1 10 ,11b1011ntlet.l. Tl1c 111;11ril( is almosl i1lc111ica! 10 1l1t· (1 .ii; naems in polished sccaiou; ho,vcvcr, 1hc 111;i11ix h·c.11l1c1s 11101c: 1J1,1,II)· .. ,1111 in 0111crop a Oo1v lui:clia "·ill .1ppr.1r 1t111i;l1cr in i;11», 11 ,1111c 1h:111 ;1 11 ..... ,\ le,11 Oo,v Lreccia, comi,1 of Lo1h l.cr&o('hpc .11111 1,111111c Ii Ji;111u1u. 0111: ~-.. ~ 1· I 4 • .. ;_ :- ( . __ ......,_ I ·-· ·r 98 CAll81£AN ClOLOGICAL INVUTIGATIUN$ ,uch occuncncc (,ample: GSJ-2, nnr the wen end of Grn1 S1. J;uncs hbnJ) ii a I00-(001-1hicl bed ol ._,ratophyrc and 1pili1c rubble wi1h a (C\-t limt· 11<mc: fragmrnu sci in an app:ircn1ly igneous mauix. Tht minor rtcry11alliz;i- 1ion o( the limo1one 1uggcus a low 1cmpcra1urc o( uUuliion. No conglomcr- am wtrc identified within ahe Waaer bland formation, although man)' Row brtcci,n hne rounded aa well•• anaular fragmcn11 and, wl1cn h'C31hcrr.d, rclitmble conglomcra1ca. °"f'411 - (.ample ST-274, Li1enlund, S1. Tho111:a1) ,,·oulil undoub1cd1f~aicil a con1lomcra1c Ly anon lic:M Kcul- ogim, b111 unwc,llhtrtd apeci .... faund a 1hon Ji11ancc c:mw;ml along the suiL.c 1how 1he igneoua m.atrh1 n-ry clearly. Tulis anJ \·olunic brccdas loran minor bur di,ainct 11ni11 in 1hc forma• 1iu11. Tuff, (l.•nin ai,c lcu 1han S2 mm) arc much more common 1han brcccia, :mJ occur as beds only I or 2 fcca in 1hickneu. None o( the 11111 uuiu could Le dcmom1ra1Cd 10 have a bori1on1al extent grc.ucr 1han :1Lo111 h;.ilf a mile. Gr.ading is visible in the tull beds, ahhough ibis gr:iding is conunpnly i111errup1ed by dias1ems rcprtscniing the ae1io11 of 1-tatcr curre1111 on 1he ac:a bottom. Slump 11rue1urcs. geneully in the form ol comonctl Lc,lding, aac uncommon. Many 111ft bcds arc silicilicd, ahhongb die origin:11 p)·roc:l.aatic g101111dm:1H is recognizable in thin 1tc1ion. App:.rcntly the origin- ally viuic groundmau of many tu Ifs bu altered 10 li11e-gui11cJ mic.1 minerals; mu'tO\itc i, the mml widespread, and ccl.adonilc and 11ilp11omclanc h:n•e been rccognucJ. One of the bc:u ci.po,urc:s of a L.cralophyrc breccia is on the eau dame o( Lamcsbur Bay, S1. John (sample SJ7). Herc a bed 1tvcral 1ens of feel thick consim of angular fragmcnas of lera1ophyrc a few mm 10 S cm in a reddish, hema1i1ic m.auix (Pl. 4, fig. -t). The hema1hic mairix contr.1111 ,.-id, the more ncuual colors of men, other kcratophyrc Rows and 1uls in which hemaiitc is generally subordinate 10 magnetite. Dikes and shallow plu1ons of llcratophpc: occur 1lno11gho111 the (oi 111.,. 1ion, b,u arc 111011 compicuous in 1l1c hills 10u1hwcu of Charlouc Am.alie, Sa. Thomas (lbypiccc Hill. Gr.amliololil Hill. Sua Ifill, Cabrirabcrg), in the: vicinity of Nuarc:th Day. S1. Thomas, and in the vicinity of lf0Rm:1n .and t.11. Zion, St. Thomas. (1\11 Zion itself, however, is unilcrlain by ano1bcr l)(lC o( inuu~i,·e 101:k.) The" bodies commonly exhibit column,11 joinain~ 1ic11icndicubr 10 the cooling surface, ;md cumina1io11 of the joinu pro- l'iJcs a means of rcco1111rucling the shape of the inarusil'C Lotl,-. The hilb around 1he Submuinc: llasc on S1. Thoan.11 (C.:abritabc,g, Gca111- Lokola, Ha)piccc, and Sua hills) arc underlain by one or awo inuusi"e bodies known colleuivcly as the Submarine Base Pluton. 1·hc accompanying m;ap and sections (t·ig. S) show ahal the form o( ahe imrusive body is irrq;ufar. The p.1ucm ol joints around llaypiecc Hill strongly suggc:su ahc IIIL'ltncc o( an inuu~i\C funnc:l benca1h this hill. The joint 11;111c1n bcnc:,th eastc:111 Sara llill. on the othc:r hand. l'loulJ appear 10 s11gscs1 1ha1 1hc Roor of 1hc: ininuhc body is s11bl1orizo111al. incgulu, .and shallo1'lly dipping here. The in1rusil-e-ex1rusive con1ac1 near a probable vc:na :11 the southtrn cnil of I ·- ·- -- ·- - -,( 1. W. lloNNLI I.\ -U. I IIOMA~ ANIJ ~I. JUIIN, tJ ~ 1 lkC,I:'< 1>1 H,11> 'l'I ~~.1mlioL.ob llill ili 1110Jc:1.11dy ~•n:p 011 C:Jl1111.cl>t·1i; lldl 11 11· ,11!1111111.11 JOIIIU arc m·.,aly lu11ilt1111.1l or 1l,.11lU1,·l1 d1p11111i; 111 ... 11,I 1l1l' "'11du 111 ,. 11,1 ol 1hc inumi\'C L0tly. hut a,e 11c.11l1 11t11ilJ) .1ppiu1..a111.1i.·I> JOO 1t-c1 111,11 11 ol the 10111hcrn COfllJll An ou1oop ol C:);llmi,c rod,, c, i.kudi '" 1 11 11 111 ,: C CJ ........ .n (Z]o•••• s=~L.., ... ,. ... I , .. D ........ ,,. ltw, ... , ••• Reth D .... , .• ,..,. ,. 1t0JI Atht .... 11 CtlvlllUl,Of J1,11h ..... ........ , ............... . ....... .... , ........... ,. .. ........................ ..... ., ............ ,, IOOO ,.,, C ---·J, .. ·-::-,r,-: ··~1·. CC L -·•. J-,;.- i,(111/ -- ,. -- L -· - ·--- l fKUa[ ' ., .. r .Jn•I UUH IC'-110111 uf'1lu: S,1tun.u111c U.1h· .,, ..... 11. '>1 1111111,.0 k, 11 I 1•1~,c I lor lou1iu., juu undcr~at,llh &he i111r111iH b0tly. 1.111 he H't.'11 ;il1111i; 1hc ,l.111<· l'"' 1.,111 1, of lhe Carabbcau llotd. lluc &he i1111mi,·c Lo,ly w.1s l'rob.,Lly lul lluo11 •h d . . i; a 11ecp con uu .al IU ~ou1hcrn cn,1. an,I 1prc.1tl 110111,,,1;11,I .,s .1 1011i;hli conformable shctl. h h 1101 known whc1hn or 1w1 1hi~ i111111,1,.: '""') counccu with the 01hc1 0111: ;.,t ~11al101" ,kp1h The occurrc:ncc of inuu~i,·c: kcu1oph)1C in 1110,k1.11dy 1.11i;i· l,,111.u 111 wud lhc lop o( the ,cc&ion 111.1y rcllnt .1 ,ululc up,01,I change 111 l11hol.,li). 1 " , -- ( 11-1 C.\RIIIIIE.AN C[OLOCILAL INVUTICATlllNS ,ure optiu). and rare bio1i1ic miu ;md a mafic mineral_ whic.h h;as ah_ered comple1tly 10 a line grained, very red subua~ce. l h11 could. be. cuher iJJing,itt, bowlingi1e, or wmc 01hcr cby mmeral or combmauon ol mincrah. The gins lragmenlS have tlillusc outlines and ,oultl lJc ,ha_ul1. In no enc, hoh·ncr, haa the dcarec ol preservation revulcd •~•c 0~1hncs ol the original gbn hagmc•u., l;~!t ,i~arance ol these lJcds 111 1h1~1 sec- tion is ,cay simillr to the .._.,, ___ ,&lied tullalcom be,h; lout~ll III CK· tilosivc rh)olitic suile5,• bu& """ 1tplosivc origin is 1101 csubh,hcd h)· l><'llographic evitlcnce. SI I Al ICIAl'UIC VAIIA IIONS The W;atl:I hl.lllll fu1ma1iun i, 1tmarhl>lr 11nilo1111, comi11ing tl11011gh- u111 ol ;about one lihh ,pili1c and 1he remainder lcralophyrc. 'I he lower •~• · 1ion ul 1hc lor111a1iun, seen best al lb111 lie.ad, S1. John, ;and on _Gac~t SI. J;uncs bland, comisu du111ina111ly ol •!•id. kc1a1ophJ_re Ho,~, wllh 1111c1·• ula1ed spili1cs. Breccias and ppucbsuc r0<b ,uc manor a~ad lorm only ,cry 1hin unils -..·ith a limited btcr;1l cx1cn1. The 11~1,cr poruon of the fo.-. mation, seen best in the ,·icinity o( O1arlo11e Amahc, St. Thomas, and ~• \V,llcr hland iu,cll dilfers p1incipally in the greater pcrc:cnlagc ol 11yr?c:lasuc uniH. ,\1uuml the: i111111sh·c bodies ol llaypicce llill, C.umbokola 1h11, a,~d C.ab1 itabe,g, the: lu1111,11io11 is do111ina1~1ly py~oclaui~, with only a few •h_m &.crarophpic floM. Un Flag llill, 511a11g1apl11c~lly ,l~gl~lly_ lower than •_hue l'>•ocbstic 1oc&.s, a ,uil.ingly ll~ic.lr. pyr?'b11~c. u111_c 11 m1crcab1cd m a Jominantl)· flo,~ ~e,1uencc. No m111eralog1cal d111111c11ons be1wcen the lower ;a111I upper pot1iom of the formation can bt' seen _cxccpl 1h;al near_ the •~p of the formation 1l1Ctc is one occurrence of ohgocb" and albnc wuh high-ltmpeunne optics, and 1l1Cte arc three occurrences ol albiac w~•h optics ,vhich de,·ia1c ,ignificamly lrom 1hc lo,v-1empc1a1ure s1a1c anJ winch hne been called qu:ui lo,v-1cmpe1.ature op1in (Donnelly, 196!). £NVIIION1'1£NT The 1110,1 suiLing (eatuac of the \Valer bland Form;a1i?n is the. co~plc1c abKnce of 1trrigcnou1 sediment: the entire cxpoM:d 1h1elr.ncu co111_111s of vokanic roch only llightly reworked locally by water. The accond 1111pa1·• 1an1 lca1urc of this unic is 1ha1 most ol the volcanic roch, except for the uppcrmou 5 per cent of 1hc lonna1ion, ;arc Rows. The py1ocla11ic aocLs 1henuch-es consist entirely o( relatively equanl, angular lragmen•~• and ,haids or pumiceous lragmenu arc 1101 seen. The 11uicKen1 er11p11011 of ;appa,cn1ly h)<ha1ed magmas muu indicate that these 111Jgma1 ,vc1~ erupted unJrr a lOnlining preuu,e ol superincumb~nl ~a wal~r approi.1- matrly e1111i\aku1 10 that of 1he deep-sea bouom. wl11ch II suflic1cnt 10 pie- vent the e'.1.plosi\c expamion ol a magm;aaic gas ph;,se. llyJr;llcl_l m;~gm;,s crupteJ in ahis c11d1onmc111 will cxpt1icncc separation ol vulaulcs 1( ll_1e I . ( T. W. (IONNlLL\'-ST. lllOMAS ANO SL JOIIN, II. S \'11\f:IN MANOS 115 partial prcnurc of these volatiles tuce.ls 1ha1 ol 1hc ~ea w,111:1 (;,bout 500 aim al 15,000 feel). The expansion of these volatiles, hmvncr. will ~ in il,c order of a IC\~ times, nor many 1ho11sa111l limes, as wuul,I Le 1he cue if 1h,· magmas 1verc erupted suburially or in sh:illow water. ALps.11 ppoc l:1s1i, rocks will 1101 be lo,metl by explmion but by 1d;11hcly 1p1i,·1 nq1.1mi1111 ol vob1iles and sutl&lcn d1illing l,y sc;1 w.,tcr. llispco;1 I of py1 nd.1\I i, h ·•!-:mu•" will probaLly be c0cctt1l by ~lmv moving bo110111 cm1cnu, 01 cu11\ r, 1 i, ~ currents initialed by the 1clc;1se of heat into lhc ~e;, w.,tt'r. ·1 he ;1hH·mt· ol lerrigcnous sc1li111c111ary tocks in,li,alcs 1ha1 lhnc "rn· 110 enll I i:1·111 i,l.1111h \Vhitl, coultl h;n·c ,crvul ;is the 101111c of h'l·,11hnc,I lkll i1m Slump 11111c1urc1 or 01hn cvhlc11ccs u( 1lcpositinn 011 ,lopes JIC p1n1·n1 hut a,c not ab11nd;1111; in conuaH, ne;,r the top o( 1hc lor111a1ion 1h,·1l' arc scn-1.il 111iki11g on1111e11ce5 of cnnly la)Clctl ppodattic ll'laloph)tl' will, no Lnl ding lli,1111h;1nccs. [dclcntl)· 1hi, fo1111a1io11 ac11111111la1cd 11111 011I,- in ;1l,)\ sal depths bur also on 1athn ll:11 sea l,0110111. ·1 he app,·,,r;1111 c ol dii;hll) more ci.plosin: Cl 11p1ivrs 0111)· al the ,·c, y 11111 ol the l-'u1 mat io11 sh11" s I hat tht· sea bollom m;1y ha,c been s11bsiili11g during 1hr g1ea1cr p.111 ul the ;1lc::· c11n111l,11io11 b111 1h;11 subsi,knet· was 1101 r;11'id l 011011~h 111 111.,in1.,i11 a ,011- ~ 11a111 ,va!c• Incl ;~I the tru!uh·c: ,c11tc1 of 1l11: acc1111111la1ul H•_lt.1nir cll·110,i1 Ahcrna1n·cl)·, rtg1onal uphh near 1he e111l of \\'ate, lsl:111,I 111m· cuul,I l1;1H bttn rcspomihle Joi· the :ipp;ucnt ,hallowing of ,c11n VIRGIN ISLAND r.l{OUI' I OIJISI Nlll>J I OltM,\ llot-. lritrocl11du1 )' Jl,1ln111'11I. l/n, maim 111:11,1)· "',., I) i11~ 1 lu· \I .,1n hl.111,I Fo1ma1iun a11J uopl'ing 0111 on aho111h.,111he IJ111l .11,·.1 ol S1. ·1 hon1;,s ,mil 51. John is the i.011iu·11hoj (l.oo ~· ,a11 l,oi) Fo, 111;1lillll, 1111111·,I '"' rx, dk111 C111'01u1c1 in ro;11l cuu in the ,·i, i11i1y ol I 1111isc11l111j. j11,1 1w1 ti, ol ( :h.11111111· Amalie, 51. Thonus. jl'!_ii~ •!~\c~_sc:.,111~1111: is 111l·tloi11i11;111il)· :111,;i1e ;1111lni1t· _aml uric~ ~n !!101lc_of depa,irion hum nrncl;1,1ic to cl'i, l.,,1i, The n1.1'.l.1 11111111 appa1e111 1hirl.11ns 11;1\e"nl is ;1!.0111 ".000 llTI, but ;1 ll',H1111;1l1k corrcuion (or lc111i111l.11i1y 111i:;h1 1nl111t· 11,is ,011111111,·,I 1hi1l11n> h) ;1 11,i,il 01 more. Cine (IKil) t;11lc1l thi, 111<l t)pc "Uluc lk.11h" .,ml 11,i, 11.11111· 11." peuiHell: .ill of 1hc 11;1th-es •11 1he \'i1i:i11 hl.11111, .,:,. l.1111il1.11 .. iii, "11111, Uitch" or "lllue Ui1." The lorm;uion is thidcu ;11111 almou tn1i1dy l'l"" l.1>1i, (l01.,lli 1n,111ll·il luff beds :ire consille1cd l'SSc111ially pyrodasti..-) i11 wnll'111 S1 Tlu,m;n 111 ca51crn S1. ·1 hom;i> the 101111.,1i,111 i, 11111, I, 1hi11m 1 ( 1111111 h-,·1) .11111 ., , 11111 posecl ;1lmust c111i1dy ul 111.,i,c ,li11111'nl ;11111 1n,·u1 lnl I') 1111 l.1\li, ,Id,,"· probalJly mi1:ina1ini; hu111 :i ~111.111 ,11L.11·1 ial c1111l' 111 "'' ,1,·111 'i1 f11l111 11,l. formal ion is chi, la·r (70110 lt-o 111i11i11111111) .11111 l "'""" I", ,I, ,111111.1111 h , ,I C0,IISC llllll' ,ld11 i,. l'ii;11u· Ii ,1111111, ;,11 i111t:1 I'' c1.11i1111 ul 1111· u1111l11 """ "111, I, 1emhed in 1hh 1list1iL111i1111 or 1111k 1u•n :111111hi,l11n,,·, hid,-,.,~ 1111 1111 116 ··- ,_.- (:· ~- ,-- ,-- ,.._ CAllllllEAN GEOI.OGICAL INVESllGATIONS 1/fll T /f-j!J Q. w i :s ~ ),. ~~ 3u C/)::1: wo Cl) a: a: "- <( Cl) o_ ~ ~1m ~1;:f . it CJ a: I ~~ i ~! z 0 ... <( :E ; Ji en t I !:: I ,o • Cl) i I 0 Q. u .. w 0 u i= (I) i di 0 .. ~ t c Q. •• Ii ' R -. .. ~ 0 i E . ~ .. I I e lil • .!. I - r • - E - .. l w z - (I) a: ... <( - 2 en m~ ::, w enc "- Q. o::E w:> ZJ ocn )_ a: 0 "- 0 z <( _J Cl) 0: w ... <( ~ ..... $ l:: ),. ~ ). ~ ~ I I ~ . I I Ql I en w _J - ::E in 1 '1 ~ ~ l 1£ ,:: i i i :::i f ] s !i ,, i -. Ji i 1 • I i:: ,;; l I ' " - l i !j 1, J! • 1· xl • ~ a s~ ~ ! 1 - - - - ~ --, -, '( , T. W. DONNELI.Y-ST. TIIOMAS ANU H. JOIIN, II S. \'IRl:IN 1\1 "Isl>\ 117 pos1ula1ed Pilbbury Sound eruptive center is b.ue1l 011 1he WJ1u·11eh ul volcanic ejecta in nearby wesic111 Sa. John anJ r;nll'l n S1. Thomas. 011 1 he presence in Pillsbury Sound of a dio,ilic f»luton, and 011 1111: 11c.-cc,sil) ul lintling lhc nc:.1rc:u 1rasonable 10111ce for 1he li1hic f1amcnis in 11,c Luuhl'n· hoj Fo1111:1tion of ,vcuern S1. Tho111;1s. In weue111 St. Thom.is (I!', miln 1111111 1he prc:suninl l'I upli\·c le111e1) OClasio11JI a11gula1 l,lu, L.s ti indu:s in Ji.1111- Ctl'I' arc fo11111l in 1he ash bed,, 1,hid1 thl·msd,·n tJIIJ;l' fiom finr 11111 111 fragments ab11111 I inch long. The co.inc cone dcln is is mou su iling in \,n1,·111 s, ful111 .11111 t:.,.,n 11 S1. Thom;u. In ,~l'Sll'I n SI. John ·I luo1 l,lucls ol i.hJI 11111>1 11.11 c l.n-11 suba1:1ially dcposiictl ash hom lhc ~lol'c:s of 1h1: w11n ;11c loun,I mii.nl i11 coauc conclo1111:ra1ic belh. NcJ1 l\bnJal in ea,1t:111 S1. Tho111.1s l.11gc: hJi; menu o( wha1 may hne been a sul1;1eri.1l an1lui1c 11111,· ;11l' )c:1·n in bind . ., of dc.-Lris cro,le1l hum 1hc cone. ,\1 one: lm.ali1y h.ii;ml'nh ol flow up lo 2 feel long rest in a 111a11ix of fim·1 111.11c:1ial. Many of 11,nc h.1i;111t·111s L1uL.1: ' ap;u1 just fllio, lo u·ss.i1iun uf IIJmpnll. and 1hcir Liull'II 0111li11n c.u1 Le: malchrd in 0111nop. This is 1lu· oiil) I'' ol,.1l,k lluw 111.11c1 i.il iiln11 ili.:11 i11 l11i1.fo1ma1io11. At lhc type loc;1li1y 1hc lo1111.11ion consists Jo111i11.1nll) of t.c,ls ol 111.11\t" anJesi1ic 11111 which, liL.c 1110~1 111 1hc 111ff seen. ,.,,\ .1pp.11c11d) h·.11t"1 IJi,I The beds arc l)pically 6-12 fc:el 1hicL. a111l ha\c l.1i1 i;1.11li11g "·ill, 1h1: rn.11\t·,1 malerial (rarely co;user 1ha11 abo111 :I i111 hes: :1 In,· 11111, ls 10 I fool) 111·.,, II,. base. These Lcds commonly show l.1111in.1r sl11111pi11i; (li1:\ 7. Ii) ·1 he 111,1>1 suiling fc:;11111e of ll1is slumpini; is 1hc.- :1lnmd.1111L' of "pull ·'l'-llh ... 11111 1hc f1cq11c111 in1c1111p1ions ;m,I 1c:1c1s.1ls of 1hc 1;1.111111~ ·1 Iii, l.1111111.11 slumping is a n:ry t.harJcleriuic k:11111t· of 1hr l.011i"11hoj 101111.,111111 :111,I appartndy fo1111eJ as follows: an ;1)h IJII w.15 dq10\i1nl un,lnhJln (Iii; 7A) 011 a slope anti dc\·clopl'J fair g1J1li11i;. i111c11111'11:,I rn c"i111ull1 b) J l.,1i;c.- angular Llock ,vhich J1:p11:sscJ lhc l,cdili11g Lclmv i1 ·1 he lmt· ,1\11 1111 101' bcc;imc col,csh·e more rapidly 1h:111 Ji,I Ilic c 0J1 sn :1sh Ldo"' · I ht" lc» cohesive, coaucr 111a1erial below slumpcd (Fig. 711), 1.111)i11g 011 i1 and e11- 1cloping within il fragmcnu of 1hc 11101e 1oh.:si1·c, linc:1 i;1Ji11t·il 111.11rii.il above. The flow was rarely rapi1l enough 10 Lccome 111il111ll'l11; 1h1: p11lkil- apart beds h,1\'e nearly all 1e1.1i11cd an 01ic111a1io11 p.11alld 10 1hc L1:,hli11g During 1hiJ procrss of slump 1hc g1a1ling lost iu 01igi11:1I a11;111gc111rn1, :11111 1he co:usc:51 ma1c1ial is commonly lu1111J so111civha1 :1Lmc 1hc: b:1H· of 1hr uni1. Additional c,·iclcncc for tlcpi ... i1ion on a slol'e is llu· 11,·.11 I) 11l,i,111i,.,m slump 11ruc1ure) ,cen in fi11c-i;1 aim·,I llifls in 1l1c 101111.11 ion Punly pyroclauic hc,ls arc 1101 ;:ih,·a)S easily ,lii.1i11g11i,lml 110111 111lf Lnl. which l1ave alumpcd and hom beds \\'hich have been 11101e or lrss 1nrn1lnl by w;:itcr curnms. Coauci f')"IOcbsiic roils 11s11.11ly rxhihi1 th<" 11.11:1111·111 angularity, the uniformit)· of li1holoi;in. anti 1hc app,11r11il) ig11l·11111 m,urix which one associates wi1h a\h ,lcposiu, \\'hrre:u liner 31h 1,nh fl'· stmblc volcanic wacke. 1 he over-all a,pccl of 1his fo1111.11iu11 111ggnu ar11.1I uuuport and suLaqueous Jeposi1ion of 1')rocl.is1ic ild11is. T1Jmpo11.1- 120 ~--- ' C.UIIH.AN C[OI.OCICAL INVUTICATIONI .,.._ Colin l'oi,,t Co11glornc10lt li1l1ofocics. Nor ,he base o( the formation in 1hc ,ici11i1y of C1111 Do1y, S1. John, and C.ibrs Poi111, Pr.anon Gardens, ,rnJ Dunker llill, S1. Thomas, conglomrralts arc inlcrbcJJrd "·i1h andcsi- 1ic p)rodn1ic anJ cl'ida11ic 1ocb. These conglomtratrs consist almost ,·111i1dy of wcll 101111Jrll lc1a1011hyrc cobl,ln aml 114.·l,l,les derived from 1he 1111Jr1l,ing \\'.11rr hlanJ forrn.ation. At Crut lby, howenr, 1hesc conglom- eratri arc more or lcu miac4, .W . ~ailic drb, is, suggrs1ing 1hat sub- .aerial crwion of the cone . "' · . ·' ----• of the un,lerlying lrratoph)·•e beds "'tre simuh.inrous. Al. ' Nat the conglomcr:uc ia composccl of "rll-rounJcJ .and f.ii1ly wclhorlcd bntophyic and lf•ilite colJbln and pd,blrs. Thcsr conglomcaatc bcda appear to have been deposi1rJ in sh;illow \\'alct, aml ,~ere not prO\hKtl o( tubidity-currrna deposi1ion. They ;11c ,.-ell soraed, ;ue 1101 graded, and have rcla1iwcly liulc mauix. Their presence indic;i1es subacrial uosion, transpo1 I, and drposition of older ro,ls Jui ing early l.ouisenhoi time. W11lc, IJl011J.J 011i1cnhoj co111oc1. There arc le,.- places "·hrrc the lOlll~ll bcth·ct·n 1lu: \\':ilrr htmJ and l.011i~c11hoj •·o,malions is ,vrll exposed. In St. John there is one ucclltnl c•pornrc of 1he conl:ict along the wcs1 shore of Monie U.1y, and ll1c1c :uc poor uposurcs at Klein 8.ay. The u1>0u11e 011 Monte lby sho,vs :, conglomc:1a1e of the Louiscnhoj o•·crl)ing a spili1c: IJcJ. The spili1c is quile fresh at the cone.act, and the o,·n• l)ing conglomcra1c cont;1ins :i ,,·iJc auo11111r111 ol W.11c:r hla11J lithologics indmling, ho,.-cH:r, ,cry fc:w rocks iJcntilial,lc wi1h the underlying spililc. At Dhary Day, St. John, thr1c: is an exposu1r of a ro11glomcra1e of the Louisrnhoi for111;11ion o,·c,lying kc:ratophyte. On St. Thomas lhe conia<t iudf is poorly cxposrd, Lu1 :in ci.tcnsh·e ex- posure of Louh,cnhoj beds above the contact at the he:idbnds between Brewe,·s Day and lhe airport is o( great interest bc:uuse of the extent of appa_rendy contemporaneous weathering displayed here. The Louiscnhoj beds here consist dominantly o( subaerially, varicolored andcsitic ash inter• bedded ,~ith conglomeratic Waler Island detritus. Souie of 1he ash units arc brick rrJ and consist solely of albi1e, hcmati1e, and a lillle illitc (X-r:iy diffraction). The albilitcd pl:igiocl:ne phenoaysll evidently withstood the wea1hering almost pcrfec1ly, l,ut 1he e111irc malic part of the roe\ has been com·crtcd to oxide. 01hrr uniu consist of ,·aricolorc:d fragments ranging hom deep red to grl'Cll, c,·iJcn1ly reRcc1i11g diffrrcntial susceptibility 10 weather• ing. Still 01her unill consist of greenish or gr:i,·ish lr.agmcn1s in a uniformly pu1plish matrix. Tl1e basal subic:rially wca1hercd unit is len than 100 lcet thick and was found at only 1his one locality. The color of the beds somewhat resembles 1hat of the: weathered hydrothermally altered rocks (discuueJ in a lollowing Kllion), but the l:iuer gratle into ,~hi1hh unwe:ithcred rock wi1l,in a fc,., feet of 1hr su1 face :ind :nc miner:ilogic:illy quite dislinct. The ex1c:nt of 1his "·ca1he1 ing is complc1dy unlike :111y rccmt wc:uhc:ring o( :iny rod. l)llCS in 1hcse ul;inds :11111 1111110111,cc,lly 1cRccu wra1hcring rnntcmp01 a• ncous "·i1h originJI Jcposilion. I T. W. DONNt:1.LV-ST. 1llOMAS ANII SL JtlllN, 11 \ \IRI.IN l\l -\"11' l'!I Anolhcr occurrence of con1e111pu1 .mcom "·1•.11hc1 i11i:; i\ I'"''• ti ,.,.,,.,,, . .i .11 Wintberg Hill, St. Thom;1s. ·1 he pout na1111al np11~111n. "l,i, h .11c ol lightly mctamo1phosc:1I 1odr., wr1c 01igi11ally 1ho11~h1 10 he ol hi1l1111hn mally ahc:icd rocl. llowcvcr, 1 Cl cn1 ( I 9ti3) nl,I\ .11 i1111, lu, 111.,d , om11111, i1111 rrve.ilcd the originally ,~c:11hc1cd 11.1111,e of 1ht'\l' 111, ~, Alin~ralogy o/ tnG/ic frugmc11u. ·1 hr p1imip;il 111i11n.il, 1111111,I i11 ,,._,1,. fragments arc plagiocl;ue, clinop) 10H·11c. d1lo1 i,, .. ;11111 p11111pdl) i1t·. ;ind :,l,11 m;11rix au,I opaque minerals. Ano 0 • HANS LOLUK Fltf 0 0 0 OUTER BRASS LS. 0 • 0 0 • 0 IMonr 0 LOUISENHOJ Fltf O Sompln ,,_ - -0 • Q Spililiud Au9ile Ande\de Monr Samples I WATER ISLANO FM An20 LT and QLT (Oonnellr, 19631 oplics HT optics 0 0 () __ PLACIOCUU: Most phenocryus. of the l.ouisruhoj a11tlesi1cs arc lab, atlo1 i1c:. about An11 (Fig. 10). Near 1he base of 1he form:11io11111;111>· p)rod.1Hic 10,ls contain a dis1ine1ly more calcic pl;1i;iodasc (Anu 10 ;1ho111 ,\11.J So111e of thac pyroda11ic: roe._. cont:iin both by1owni1ic anJ IJL1atluri1ic lrag111rnh, but a few contain only by1owni1ic (or a11orthi1ic) hagmcnu ·1 he f,hbpan a,c: sharplJ cuhcdul and 1ligl11ly zoned. They show ab11111la111 siml'k u,·i1111ing and some albite twinning. Grourulmass plagiodases and pl.,.:iu. l.11,·s in 1he m;itrix of coanc pyrocl.,nic rocls :\le ,cry fine Gllinc,I ;111,I cl1111.ti !\I.my arc distinctly more sodic 11,au 1he 11l1c11ocrys11 a111I 1;111gr in , ;11, i11111 , 111111"111 down to An18 • In many IJpilli 11111s, 1hc only fc:Mspu 101111,I is Jl1,i1c (,\111); I ( --'. ;~.-.. .--~. r-- ,-- ,-- I 70 GARllllllAN ClOI.OCICAL INV£STICATIONS compo~i1iuu of 1he 111ore 1ilicco111 Jilk1c111ia1cs. The cxpeiimenu of Yoder .anJ Talley ( l!lti:!) d1tn" clc.11 ly 1h.a1 ac waler preuurc:s grra1cr 1h:in a~ul IOOO Lau, 111.ueri.al of Las:ahit: composi1io11 shoulJ hi: convcrceJ 10 a max• 111,e of hu111Llcnllc anJ pl,1giocla1e al 111lJli,111i1lu1 1cmpera1111e1. ~s the 1cmpera1urc rise1 1hc m,ucrial will begin 10 mch: wi1h _1hc plag~oclasc Ltmg coruumeJ r..u. The fin1 liqui,11 proJuccJ wall Le lughly fcbac.;11111 siliceous. ·1 he <0mpoii1ional 11qld of li,1uiJs produce~ 11 111ccemvcly hii;her 1cml'l'&,11111cs ha1 1N11 tae- cxperimencally de1ernum:d. h111 ~ coan- p;uiwn ,,i1h ,he anJloao111 ,.,--,~c in anhydrous caKs ~en_erauon o~ LJsah) sui;i;nu 1h.11 hornblaadr 111111 take 1hc: pbcc of d1opuJc: .is 1he Jomi11Jnl m.alic ph.1\C being consumed during 1he greJ1cryar1 o_f 1h~ 111ch- i11i;. 1 he h)lhuus liquid 111ii;l11, therefore:, be more enriched m S1 th.an ,,ouhl co111pJ1JLlc li11ui1b cocxiuing wi1h diopsiJe in 1he anh)'llro'.•~ c.ase. ·1 lie u1en1 10 1..l1id1 residual hoa nblen,lc: mii;h1 conuol the comPoullon of 1111: li1111i1b ,,ill 1101 be: easily ev.alu:atc:d un1il 1he1e hornblen,_lcs c.an be 1 ollcueJ .anJ ,1n,1ly1.:J. but 1hi1 comiJcr.a1ion mii;ht prove 10 be pa vocal. The quamiay of kera1ophyric magmas generate~ is prrh_aps l~C 01~ly rully serious 0Ljec1ion 10 the hypo1he1i1 o( gcnera11011 of 11111 en111e sune from 1hc upper m.1111le. The quJ111i1y of siliceous roch is ~nknow~, b~l geologinl inkrence (opo)eal a1ca of Water _Island Fo,~;1110~. "'luc~ H aLoul 80 per ctnl ler;atophyrc) comLined ,.,uh geophy11cal mfor~auo~ (11:ismk rcfr;,ic1ion .anJ grni1y) suggest 1h.11 1he \\'ate~ hl.1nd Form.111~n 11 a paim1 aLu,u 5 lm 1hick. cucniling perhaps 40 lm In _an eau-wc:i.l dircc- 1i,on, b111 ,111i1e pouiLly chinning 10 the cnl, anal exaendmg prrh.1ps 20 lm in a 11011h i.muh Jirn1ion. This ,·olumc:-4000 en lm, or 9200 cu lm of luJloph)lc -i, p1oh.1bly ;1 m.,,.imum, because ponible 1hinning 10 1hc l·JU an,1 10 1111: s11111h "';a5 ignureJ in 1hc calc11!:11ion. If fusion of 10 per u-111 u( 1l1e 111'pc:r 111J111le miglu yidJ a lera1ophpic liquid, 1hen 52,000 w lm 0 ( "l'l'cr mantle ,,·tic (meal during 1hi1, igneous epi10tlc:. If 1he deplh ,,r f,1~ion h.lS 10 l III and ,lac easi we,1 holi,onlJI ex lent of fusion 40 km, 1h,n ,he horiw111JI dimcmion o( 1hc fu1c:ll zone in a 11011luo1uh direc1ion 11111,1 h;11c l,.:cn 80 lm. These liguics may he off by an onlcr o( mag11i1111lc or mo1e, L111 1hey t·111pha,i,c one problem: 1hc ge11era1io11 here of 1iliccous m;igma hom 1he upper m.1111lc may require 1he p.artial fan!on o( more ma- 1crial ahan c.1n llirccily underlie the ,·cnl, 11nle11 the fusion cx1cnded to greal Jcp1h. The c:xplJn:a1ion for 1his 1ec,111ing paraalox is as follows; i:>ming ihc orogrnic proceu compression and 1l1iclening of h)dr.11ed C;anLbcan nuu and upper m.1r11lc carrieJ chis maaeri~I in10 1he o~ogen _from :i co~- 5i<leuLlc J,uamc pcrpcnalicul.1r 10 the axis of ,lcpreuion. 1 he orogenac 111Jgm;i1ic process clarn c;in be compareJ to a mill 10 ,vhich is fcJ fresh, hy· ,laa1t1l ul'ptr 111.11111c, a111l from ,vhich l\vo 1110tl1111s, m~gm.1 a1ul nufic IC· ,id1111m, ;i1c tl·mmc.:,I. 1hc liru 1l11u11i;h ;1sccn1 a111l a:r11p11011 an,I 1hc 1,tco11J il110111:h i;1 J1l11JI Ji1plJce111u11 1lm~111,·arcl .11111 cn:nuully l,11crally: The ., 1111,cml 111 lnJluphi1c c1up1a:,I 111ii;h1 h,11c 1t•1'1iH·tl l:11cr;1l sho11cn111g of .,l,11111 110 l1n in chis Ocru. The c1u,1111i1y of siliceous ignco111; rolk St:en h1:1e i• I.or in eueu of ;111y 1ha1 hJs Leen recorded in similar orogcnic ,ones, and ( I I ·---,, '--"' ( T. W. ()ONNll l\'·-ST. TIIOMAS ANO SI. JOIIN, II. S \·11tGIN 1~1 ANUS I ]I the Virgin lslanal, may Le an c,.1re111e example of J pi 011·u 1d1icl1 h.l\ 0< curred to a tc~sc, cx1en1 in m.my places a1 many 1imc1. ( :ka1 ly our know I eJge uf the composi1io11 of uppn 111a111k is 100 limi1 .. ,I ,II al1is 1i111c ICl a,,n1 1l1is pr0Llc111 funhcr. 1 he wri1er (Donnelly, 1964) aho poinic:d 0111 1h,11 1he gcnl'falion of J accond. s1rengll1ku ph;ase (a,p1eo11s, or h)d1aH·al siliu1c ma:h) duri11!; orogenic chickening would h.11c prufo11111l 11rm1111al implicJ1iom ·1 he ,·olumc in IYhich this phalC ,v.cs gnac:r.aleJ would Lecomc c:he111i.1ll1 11re11g1hleu, and rhc 11ra1ctural prcKcss 1Yo11M Le cxpct1ecl 10 cl1Jngt· ho111 a rcla1ivcly 111il1I 1hitlcni11g lo a 111ore violc111 mm·cmcnl .11011,; .an 1'111.-11· ,h·e shear. 1 he come1111c11cc:s of l11is 111011a:111t:111 i.0111.t Le 1hJI 1he i,IJ111l pla1form 1rn11ltl be raised lo an c111crgn11 k,-a:I .• 111,I po~siLI)· an a,ljoi11i11i; ocr.inic 11e11d1 1,·011111 Le loama:cl. The clkcl 011 1ha: i;c11c1.11i1111 of ig11c1111s mehs woulJ be 1ha1 1he r.a1c of 1kprnsio11 of m.1111k 111J1eri;al (.inti 1l1e rate o( he.acing) sho11IJ be incrcJsnl g1c.11ly. Aher 1his profo11111l slf11(1111;1I crisodc, the gem·ra1io11 of magma will Le reb1ivcly r.api1l, anJ 1he p1opo1 · lion of malic 10 fc:lsic magma high. The reuriccion of abunJJall siliceous magm.as 10 1hc early u.ag1·1 of 0111cn1ic cvol111ion is um,is1c111 willc 11,i, idc;i, In conclusion, 1he folloh'ing poi111S 5<:cm ,,·ell cs1ahfolinl. (I) r .. o 1)1'"' of chemically unifoun m.1grn.1s wnc c1·nera1l'II 1hro11i;ho111 1lic sp.111 of geologic his10ry o( rhese islan,ls. (2) Th1·1c hJs b<:cn i111n.11111111 ol t·ricpanl magmas ,vi1h 1hc environ111en1 in 1hc t.1sc: of Jib Ii nd,a11ge in cx11 miH· keralophyres. O1hcr possible exch.cngcs have 1101 Ln·n cs1.,bli,l111l. ncq,1 1ha1 a few ,amplcs of highly me1a111orphosccl ker J101,l1 ire, h.11 c htc11 i111 poverished in a Ila lies. (~) The sili1cous 111.1g111:cs a qH null 1<111.11 i 1 (I •\I, 01 I mclu dcrfre,I by panial fusion in a 1lomi11Jnll1· so,li< 1·111·110111111·111. l~1tl 1110,1 prob.1bly. in an cnvironmenl wi1h consi,kr.1lilc c.1ki11111 ·1 he I.cal'! bd,.I\ i, 11 of rhis pres11ml'd c,1lci11m remains one of rhe i111po11.1111 .1110111;,l1n Th" parent material, for dil'ene re.asons i11d111lini; gc.:opl•) ,ic .11 Juel d1c11111 ;ii n 1 dencc, is comialcrcd 10 be upper manllc. (I) The mlli< 111.1i;m.1s JH' chn111 ully similar lo SO·callcal high alumina LJsahs 1ypi, .ii of oing,·uic u-giom gcne1ally. The high magne1iu111 of 1hc spili1es rcrnlas from iis g1•11t'fa1io11 from a malcrial largely deple1eJ in iron by aLi.1rae1io11 of lc.:rawl'hirc ('>) The: increase in aluminum ,~i1h 1imc and 1he l1igher n111111.1111e Ab/(! r.,1io of ~he later 11ua1u-andesinc porphyries of 1he seco11cl group 111.1y intli1;i1l' genera1ion a1 incrc.1sing dcp1h wi1h lime. (6) C:rysul sc11li11g .111111 ai.similJ lion of wall rock were probably of li11lc impor1;111cc i11 11,t· gl'nl'1.11iu11 o1 dilfcrcnriation of 1his suirc. SUMMARY OF GEOLOGIC AND TECTONIC 111.'-i IOR y OF TIIE NORTHERN \'IRGIN ISi.ANDS The 1rc1m1ic en1l111i1111 ol 1hc l'11n111 lti,11 Vi1i;111 hl.111d, .11 , ., 1,.,, ,ol 1e.1dy been discuneJ by 1he wri1e1 (llo11ndly, I !l(i I). ·1 lie lullo1si11g Jtc 1111111 s11111111ui,i11g 1he geologii; hi)1U1 y of 1hc 11011lic111 V11gi11 l>IJ111I, cl11, i,l.,1n ·-· r--, \. ,-1 l.'..\RIUUCAN Gllll OGICAL IN Vt SI IGA I IONS lhl·sc iJc:.1> 1ml i1111mlucc:s 110 nc:111 t011cq1u. The 111;1jo1· c:ut-wnl fouh il,Ju1cJ IJ1cdy hom gr.avily c, i1lcn,c ,., .. , 1101 1l'Cui;11i1c,I al tl1c 1i111c th;11 fllpc:r \\·as prc:p~rc1I; howncr. ih e1d\lencc rc<j11i1c\ nu m0tlifi,.11io11 ol 11,l. i,k.1s prcu:111c:,I. The lcratophp,·s anJ spilitcs ol the Wa1c:1 1.1.11111 i:orn1a1io11 wc,c <::1.1111JlJ on a rcbthdy H.at 11:a !Jouom, :u i111lica1ctl by la,k of 1c11ii;rno11s ,k11 it.ii sctlimc:111 :11111 paucity 9' '11111tt• st111c1111rs in most 111lfolco11s nnih. A 111;1jur c.1u-,,cu high•.11111!;'.1.Meit i•fcncd hom g1;ivi1y d,ua '"•" 111ob- ,,hly the lows of t·111p1ion of 1bnc ••acn1as :is wcll as most of the l:11u 111.agmas. fll<lH'IIICIII) alone 1l1i, lault si11111ll.im·1111s \\'ilh CJll1'li1111 lnl Ill acc11mula1io11 of 1hc \\',ucr hl.a111I r0t.h in a b;uin wiih .i sh:111,1,· cklinetl 11or1hr111 cdcc:. The, c is some c,·ideuce of shallo,ving ol the 1va1er le,·cl 1owa1d lhc end of \\'a1cr Jslo111d 1imc in 1hc grcalcr proponicm of 111ff,u·c:011, Lera1oph)1t'S at the ,cry top of the section. The cml of Water Island lime ,,·u marLcJ b)· abrupt eme1gcmc, pt>5'ibly in p:in along die majo1· c.ist-wn1 f.i11h no1c,I pre, iously. This mo1·c111e111, as ,vdl as snb5tt111c:n1 mou·111cnh along' this l.auh, "·as of ;an op1io)itc scn1C 10 the original mo,·cmcnt: 1hc no11bc:rn siJe "·c111 dmvn. O,·erlying basal Louiscnhoj beds wc1e cleposi1e1I s11L:ieri.all)' a111I ,~c:.11hcrcJ 10 fo1111 a bricl-rcd M>il completely unlilc an,· 1ha1 ire f1.>1111i11g al 1he p1nen1 time. lntcrcabtcJ conglomcra1es of p1c- JominJn1I,- Lcralophpic claslS ,vhich arc especially abund:ml near 1hc hue of the· l.011isc11hoj sh°'" 1h:i1 there ,v:is a rather pcrsistcna emergent ,m1rcc air.a of olilc:r roch CXf>OlCJ :it 1his time. Slow subsiclcncc aher e,11 h l.ouisc:nhoj rime is rc:Hcctcd in 1hc gr;11hul diminu1ion in :ib11111l,111le ol lOIISlon11:1a1ic unin, 1he finer gr.,in ,i,c or the: r,rocl:1,1ic Jc1iosih ;11111 1h,·i1 rc,,01 lcJ c1111h :ilcnu. ;and the inucasingl)' cxcellc:nl gra,ling ol 1he 111II Led, 101,·,ud 1hc IO(' or the fo1111a1ion. The o,·crlying Outer U1a,s Lime• stone rc1uc,cnu almou complc1c ,·olcanic c111incc:ncc ,mcl sub,iclcn,e helm,· 1l1e lc,·cl or effee1h·e ,va,·c crmion of the older rocl uniu. The bccinning ol T11111 lime ,~a, the beginning or rc:ne1'iccl 11iHe1l·ntial \Cllical 1110,emtm, hilh newly c1ca1c1I 01 1ej11ven;t1ccl ,1ecp sl1111c1 shcchliui; ,,·.icles i1110 w.atcr ol 1111Lnown ,lcl'lh. 1::mcigcncc of IMII ol 1hc MJ1111c .arc.a is sctn in the abundance of p;111i;illy wca1hc:1c:d Loui)Cnhoj rrni;mc:111s .among the Jcuital component or 1hc: 1'11111 Fo11n,11io11 ancl itJ 1hc in1c_,. ulatcd l>lo,Ls or louilifc1011s li111c,1onc ol 1he CoLi l'oint l\kg;1l11ecua li1hofacics. A b1 id period ol 11e;i1-c:n1c:1gc:ncc i, seen in Ilic C:ot1i;o C.,y 1.imcslonc Member. The 1ecr)'st.illi1alio11 of 1his unit is 100 cxac:n,hc 10 h;nc prcsl'ned an,- of the diagnosiic pc:uog1.1phic ni1ciia whid1 might ha,c rcn:JkJ 1,omc1hing of iu c111iron111cn1 ol dc:posi1io11, Ima i1s mauh·c• 11c" and m·.111) p111c c.111 i1ic: ,1111111mi1i1111 ,l11m·, 1h;11 i1 11111\I h.1\l' •~·1·11 " l>.,nl dc:(1<ni1 ul nc.111)· p111c sldc1.1l 1lcb1i, Renc:wc:,I 111ha11i,111 ;,hc1 T11111 1i111r h ,cu1 in 1hc 1hicl ;111i;ilc ;imlc:,i1c fl)IOClastiL rocls ol 1hc I l:im l.ulliL hm11.11i1111. Mi11ca;1h><,;ic.1II) 1his ;1111lcsilc ·•l'l'l",11) I0 l,c: iclc:111il,II 10 1h.11 or 1hc l.1111i,cnh11j ··01111;i1i1111. l'ou ll,111s l.ollil Fo11na1io11 l1is1111 y h 11l1>1111c in 1hc Amc:ril;in hb111ls ,._ - -- 1. \V. IIUNNUl.\'--SI. llloM~S ANII SI. JOIIN, 11 - s , 111,.w "' \NI" I 7.1 and h.a, l>nu lrc:.uc:,I in mo,e ,k1a1I L llchl. I . . V11gi11 hl.a111h. A ,laie of Al 111 1 Y cy ( 1 !lhll 1111 >h) 111 rhc 111 ir i,h • 11 ' C UlCllc llt'ar 1hr 1o1, I I -1 I 11011 (1vhid1 iudmlcs •he II I II' . 11 I 1l' 01111 ., 1·01111., Ju, ,o 1.. l·o1111·111oi1 II I I l l I lllt·n1IK'r, in •he llrilish i,I iu I ) . . LI. I I • ' c, n ') l' ,lq ., V. . . '• t ,1.1 " ,n I ,c 11•1: ul ti 11i;111 hlan,I, Gio1111 Tl . I I . . • o •c "l'l't'I 1"111 ol ,,,.. I . . It ,ui;.- ,,1111111111, Ill ti, . II . I . I I . t IC ro11ol.1 1:u1 Ill 11i1111 . I , . l I II I> I h ,1111 > 1111111,I, , . a111 " al'1'·•1c111ly < 1111. . fus,ililcio11s Ne L. 1-· . ' u 111111i.111t•1111s "11l1 1l1t· 11 .. 11 l er 0IIIIJll011. lloriw111;,I foncs o( any oric111.,1iu11 1,1 l)C I . •11 SC:11\l· 1.1111101 l1l' ,huh II 111 1,.,, ,· · ... ' an 11111m11;1111 101,· at auy >l.11•t· I N I I D I 111111l:: 1111· •. , ........... 111 1111, ,Ill .I ca1_ y ;a I_ lhc s1111n111JI u·l;i1io11,hi a olh1·11t·d , . . SIIJllf;IJJ1l11c di.u;u kt o( 11 , l . I · · s hdl .is 1111: ph)>ll .,I b . . ll 11" 1111115, ,.111 Le 11111,c t· I· . I • I aHs of tl1llcrcr11ial 1 ·JI· 1 .,u ) o.,, .1111t·, 1111 11,l. l II ,I 1110\'l'IIICIII\ /\I ·uiy ( lllh I . such 11101·c111en1s ocu,, · I I . · · I' ·111 &:S ;11111s• \\'l11d1 1t, 111•1)' 1.n·e c1111111111c:,I I I I I · pbccmeuu hom C:.-c1;1cc1111s lo call . T. . . " ,c I ,c ou o( l.auh "" c:111.• ) '-' 111·11 Y 111111', ,1111I nc11 lo 11,c 1,1,., The p1oblt·111 of 11,c gt·11l·1a1iu11 ul 11, . . that of the S1111t1111al r,·oh 11· ( 11: n1.1g•~•~s" i11n.i11,.,l,ly 111,lt·tl h'i1h 1 011 o 1 1c aic I he g . · ( 111.igmas is co115i,lcn-d to Ii· 1 · 111ciJllo11 o all ol 1hc • JVC: OICIIIICI JS a re I r I ual fusion of h)·dr.11e1l "l•l'ci ma111le . . 1"'. I u I ic 111111c or Ins 11,11 lo11111I beneath &he C- .LI S n1.11e11a • 1Jt·111ic,1l lo 111.11 l'•cs,.-11111 ·•111 ,can ca al clt-1ul11 L •1 r. bclo"' the sc.i Uoor Tl . 1 . . 1 .. c: IVcc:n :> ,11111 I 01 111 211 L 111 I . •t Jrgt , o 11111e ol ul1Cc:011s l . I cu,·, cx1e111, •he ,·olumc of I· 1. r. • IIJIOp l)1t·. ,111tl ,., ., I a tr m.111c iod.s, 1c111111n ii . I . I man1 c o,·c:r a ho1izo111·1I CllilC:nl · 1 b ic ll\11111 o "l'I'.., . • com11 c1J ly gic lln ti. 1 mc:nuons of lhc o111nopping ro, l uniu If . . IJII r _•e p1t·sr111 tli hytl1a1c:d 10 10 15 L f · Ilic lus11111 "'•" li11111ul 111 ll1t· 111 o uppcr Ill 11111c 11 11: 11 ih I I tion for the ,·olumc ol ma •ma cr11 ;,c,I i~ . c_ on y a, c:1p1.irc n1,l.111.1 portccl adjacent, unfusctl ;,a111lr i!110 lhc •~;;,ho1u~,"'.·'' mmc1111·11h r1.111> laco11rd, parii.illy fu)Cd, a111I lhc:11 i1s rd1.11 lo ~en._ ,, •trc II was dt p1 l'>H·1I. dow11wa1d and latc:i-allt·· I) in11l1111111 sl"" 11· tli,pl.11 nl ~he c1·oh11iu11 of this po11io11 ol ihc \\'cu l111lit·s . . uf JUxla~d. 1,hysic:illy lo111rasii11c pb1cs of um:> ••·•~u.,lly iht· inpcm,t· an "l'f'licd horilOtllal lorce •·~1-1 .. 1 1 . . ·1111 "l'l't·r 111.1111k 10 · " lllt: ,I 11111: I IC JOIII I rci.ulacd in thicLening and tlowmn ,· • . . . . lt'I\Vt't n lhnc pb1n lime), followed Ly ,011111rcuilc f··1·'1I mg •,11 1ll1c 11111~.11 )l.1t;l'S (\\',11n hlJ111I f I ., IIIC, I IC 01111.1111111 f . · iu l 1)'5lcm, and rapi,I uplih ,,hi h f ·J " -~ 111.11111 ic:1.-Bc (Louiscnhoj time) anti, III0SI ,,;ub;,~ly UI "'\. ~·'. emng,·uc hl.111tl I''·'""' Ill :application of co1111 . . . f . a11 a, 10111111g o1 c:.1111c lll'II• I, hu thn ,1us1,c: 0l(cs c.iust·tl f1111hi:r II. l. . . c111c1g,·ncc of •hr hl,11u.. ,l.11for111 Tl . . '" . •111111: .mil , u11111111< ti Islands 1J1a1 aubmcr cncc I . . lt'.c h no c11tlt·11•c "' iht· \'11i;i11 hi.ind tin1• •t·,,.n,a g. of any mlg1111utlr ncr ote11r1t:il .,lrn \\',11n ... ,. • n was gcncrJtt"d Ly 11 · I ( · m:intlc· the prOJJOrlior, f ·1· •c pa111;1 ll)1011 o( h)1l1J1nl .,,,,,,1 • 0 SI ucous a111I nnfic IIIJC . . Ilic ra1c ol deformation 111d ii . • f • ''.'·•s .,1 a111· 11111•· 1t·II,·, ,, 11 . IC 1.11c O ll'111pna1111t use. IC eastern Grca1n A111ilks is a u11i1111c nhil,i1 of I I I(' i,1111111 f1.11111n • Su f,•,.1101t 2. l'~c.- Uu. _, : ... .,' ·-J l_j :~ -- -- IH C.\llDIILAN ClOLOCICAL INYlSIIGATIONS 0 ( 1hc u11h'1 hlJnJ uu. This ;;uu hu never been blanlcu:J wi1h 1he 1hi,l 1cnii;c11uus 1c:Jimcnu '"hich ha,e mocJilicJ :mJ IJter ~uiJccl the .11uc1uul e,oluaiun o( muu o,ogcnic regions; ii np1cscn11 1m1cacl the di, eel inu:iac1iun of occ.1nic ca uu anJ orogcnic force1. The failure: of thl"se 101.Ls 10 h;nc Leen 111etamorphosc:d :md 1hc:ir subm1111:nt cxl111111,11ion i~ a nclily prh1ine co11Ji1ion arc pr~ably 1hc remh of :a lncLy gculog1t;,I JcciJe111-1hc Jc:,dopmcnt of a1t •1t111h·e 11rile-sli11 f;auh 1,-sic:111 ""'."h of 11,e i,b11J pla1for111 Jlong whil!h ""c rnolvcJ 1hc hull ol 11_,c: 110)1-l:01.c:,~c lldorm;i1i,c forus. \\'iahin the i.1 .. 1111 pl:11fo1111, 1hr 1l0111111:1111 U"llu111l lunes han: hc,·n Jillc:ren1io1I ,·erciul movl"111c11u umccl hy 1hitLe11i11g ;11 Jcl'lh. Ahhough none o( the suuctur.al or pcuoloi;ic.: conclusion~ clc1h·ccl from 1his 11udy un ncccuarily be applied 10 :my other spce1lic ;1m1, nc,·cr1hclcu cer1.1i11 oh5erva1ion1 cannot bil 10 uisc serious q11es1ions con• H·rning lone uanJini; geologico1I hypo1he1Cs which hnc nol been seriously 11ucuio11cJ in 1ccc111 years. REFERENCES CITED llo.;c;u... 0. I. 1907. O1D Dan1k·V,11inJi~111 C~olo1i: C~oaralilk TlduL1U1, llon. l>a111k1. Ccocu1,h. Schhb. w. 19. p. 6-11 (Tumla1rJ bJ t.tra. £Jilli Thrilc, To11ola. ft.V.I., and ruruineJ bJ 1hc w1i1cr) Bu,.u: f .• 19~1i. Zoni6uci6n microlau11i11iu Jc lu caliu1 u~1Jcic11 dd n1c de t.tr•icD: Dul A,oc. r~11ol Mn .. w. I. p Sl~l1 llu,.lN. N. 1 ... an<J Tunu. 0. f .. 1950. The ,,.1e111 NaAISi,O, kAISi,O,·11,0: Jour. Ccul· oc,, • Sd. p ◄H!}-SII . bu,u,,.LtO .. , .,. t·., l'H!I, C11ni1c cmpl•ccn1u,1 wi1h ,p~ci•I rcl.-.r11cr ID Nu11h A111rr1u: Au<'"-') 1<,ic,., Crol. Soc. A1ncriu Bull, w. 70. p. 611-741 cu. ... Pu 11011C>u. 1871. On 1hc 1rolUCY of &hr nouhcu1cr11 Wrll India hlanJa: SlutL· hohn. 1-uni:I. S,cn,La \'c1e111l.-AkaJ. lbndl .• no. 12. p. I-ti. -- 1191. Ou1l111c c.l 1h~ 1culOIJ ol 1he 11011hu11n11 Weal l11J11 hl~11J1: N. Y. Aud. Sd. Annah. w. 21. p. IIS-192 CuaMUUI, II. P., 19SI, lu1 fuse dn Abu11~<Ji11cu11Jc11 <Jc ■ lladiula■ilr: Ccul. Rund., BJ. SI, p :!1 ►:21 Uu~"uu, T. \V, 19>9. The ccolug ol S1. Thomu and S1. John, Vi11:i11 hla11J1: :!d Cu,t.t.,·an Ceul Conl Tu111 (ll>b1•1uc1. Puello Rico). p 1si-1Ss -- 1962. W4 i11Li1c in \\'ell Ir.Jiau 1pili1ic 1ocLs: A,n. t.lh1c1alu1i11, w. 41. P· 791-802 -- 1!16J. Cc11ni1 ol alt.i1c 111 carlJ 01111c11ic wulca11ic rocls: A1n. Jou,. Sd., w.,261. P· ~7- 912 __ 1961, l\ulu1iu11 ol u11crn An1illu11 island arc: Am. Auoc. Pcuol<·u,n Cculuai111 bull • w. ti. p. Ul>-696 . . , -- l!IGS, Su•bullom morplaoloCJ 1uacn1iwc ol poa1-Plci11el(cnc 1rcto111c acll•IIJ ul 1hc casicrn Crcarcr Amillca: Ccul. Sue. A1nc1ica lull.,"· 76. p. 1291-1291 •l.ll;ut•UA•"'• P .• and •tiu1uon1, G., 1161, 1166. t.tcmoi■c ,u, In Coralliark, do An1illt1: Mcm. Aud. Turin. :?J Kr .• •· It. p. 279-565; •· 25. p. 19' E•11.a. I. \\'., l'J~t. The ceoluaJ ol 1h~ Rrili1h Vir1i11 hla11,h: Crol. t.la&, w. 61. p. 5'9- JSI t, 11, W. S. ·1 u,-u. f. J, and VuuooCIN, J.. 1951. t.ll'l•mo1phic 1uc1ion1 a11d mr,a• mu1pl11c l1cit1 Ccul Soc. A11 .. ·1ica t.lrmoir 1'. 260 p. • Nu1 cu,aincJ t.J 1hc w1i1t1. a ,._ - - ~ T. W. IIONN[LL Y-ST. TIIOM AS AND ST. JOIIN, U. S. VIRGIN ISi ANIIS 175 11 .. uuoN. W. l!lCit. Ori~in ol hi&h 11111111111 1,aull, 111Jcs11c, a11,I ,I.cur 111•i;mu: S<1rn«. w. 116. 1, 6,5-un lluun, J. J, 19~9. Some D1l11cr1logi1JI <qu1ht.1i• i11 lhc 1)11<111 K9 ,\l,O1 S,O, 11.C I Am. Juur. Sci, w. 2S7. p 2U-270 lhau1,. J J.. ~hr••· c ....... , k1u111•. n. II. 19til. Some JltC1.1(h1II ,,-.u1io11, Ill dn IJHl'III N •. o Al,O, SiO, 11,0. II. S G,ol su .. ry ......... , .. 1 t"!III. I' HM )10 11, n. II. II. ICJ14J. (:lu:micJI cu111po1i11un ind u1,11, JI 1,1u11t 11u :1 ul cum111011 cl110,1•)1u,1 11, \ l'•II I: .\m Mintului;iu. •· 54. p 6:!I 6h6 llc1t.•o". A. C. 190S, 1111 l',·110Guphi1· ,lcr llrn1111 A1o11lh1o 111,ul,. llull 1;,-.,1 1.,., Uni•.• li (l!I02-l!!O,). p. :.!it-2,:: •11011fi1a11.•. II n. 11110. No.:lc Ut·mJt1l11i11t;n OHi ~I I 1111111-n t.111!_"1111,11 ~L.111,IIIIJ\l\l.1 Na1u1 lunlrru. :Mc1 Muo.k. p i61- JGB •-- 1816. IJrlK-1 Ji~ 1nintu11i1ehcn Vo1lomm11iut Jul ,1,, ln~d S1 lhP111.u K.1ll. :.!1111 \'en dtr N•1url. unJ Ac111c, p. ~6:? :!61 Ko,r. J. f .. 1926. Gculocr ol 1hc Vi,i;i11 hl1mlt. Culchu. auJ v,.-.1''"' l11cr0<lu,1io11 .... J 1c,icw ol the li1~1aru,~: N. Y. Au,I S,i. S,ic111if,c Sunry ol l'ullo 11.iw a,,J 1lu· Vi1i;i11 hl•11J1. w. t. 1•• I. p. l-Ci!I ktNNUt, G. C .• l!l~O. P,cuuu: 1-ulumc 1rm1u.:1,uu1e 1cl•lions 111 h,lln .. , clt:\JtcJ 1rm pcra1u1<1 auJ prcuur~s: A1D. Jour. S<i, "· 211. p. St~Sftt 0 1lNua, Ru. J. P., IIS2, A hi11orical acco11111 ul 51. Thom:u. \VI: N<w Yo,L, Cluil<t Solbnu and So111, p. 207-219 lu111L11N. C. C .• arid 1.unww. P. W., 19S6, n·r,c rcl•1iu1ul,ip uf Ilic 1l1r1u10tltn•mi<•I p11arac1cn I'• T·I' lor 11,O anJ JO-:-. a1111wu1 NaCl 1ul111i11n1): Min Sue. USS 11. Tuna. w. IS, p. s~nt 1.101u, [, G. 1965, Pcuo'°IJ ol andc1i1ic. 1p1li11c. anJ ke,a101,J,111c llm, 101L. 1111111, crn1ul Puello Rico: Grol. Soc. America bull."· 76. p !,) 88 •t,IAcLUU, w. 1117. Ot.1eru1io111 "" lh~ g,·olui;r ol 11,c w ... , louli, ,.,, .. ,h 1,,,111 11,,1,.,,J,., 10 Sa111a C1111. inclu1iwc: l'hiladclplo1a. Juur AuJ. Sti. • I. I' Ill 11') lllltallotf, II. A., 1926. Ccol"IO' ul 1hr \'i1gi11 hlau,h. Culrl,i,. 411J \'1t·q11" l'l,p1ng ri1play; N. Y. Ac.ad. Sd, S<iC'n1if1e Suul'J ol 1'0110 ltuu .111,I 11,t \'11.,;111 hl.uuh. ~ t, p1. I, p. 11-ltl; p1. 2. p. 1-219 Nic1101u, C. U., 19S9. Aulumt1a1oma1i1111 i11 11,c lower 1p1h1n ul rhc Uu,hh ,oh•n" acrin: Quar1. Juur. Gcol. Soc. l.on,lun, •· Ill. p. IJ7-16l Noc.ao1..111, s. a, and AtUN, ll., 195J, ·1 he ccuclot<Diu,y ul lulllt ign.-ou, rn,l ....... Ccochiia. Cl Co,iaochim. A<la, "· •. p. IOS-112 On1cu. C. B, [lW1Nc;, J. , .. HtNNION, J .•... 11 ....... u. D. G. anJ M,u u. II [, l'lS'l. Ccupli)NUI in,·c11ig•1io111 in 1hc c,11<111 Carit.Luu: 11111o111••t ul 1%5 anJ 19~6 uui1C1, p. 17-109 it1 l. II. Al11c111, f. l'1cu, K ll•nlam•. aml S K R ""'""'· £,f,ton. l't.y,ia and Chcmi1UJ ol 1hr [a11h. Volume~- l.onJon. l'•·•i;•mun l'rr>.1. tf,I p. Oav,ur, P. t,t., l!JliJ, Allah 1011 uchani;,· J,uw, rn ••1••·• a,ul ltlJ,1••• pl,,,c Am J11111 Sci .. w. 261, I'· 201-2'7 OianaN. £. F .• 19~!1. llult- of ,u,)t;tn p,n.uJn· 111 1i.c <r)1Ull11.1111111 .. nil 1l1tlon111.1111,11 ,,f baullic macma. Am. Jou,. Sci., w. ~). p. 60')-C.17 Rii1111, II. J., 1!161>, Zur Pcuoeul'hic. Ccod,~mic und Gcne1c ,In M•i;n••• 11, 1111,I I •~•, IIIIIC'D d«-1 Obt:1dc•on1 u,uJ Un1r1Lul.101u in Chu tau, i1•~r11 I 1nl,1 1g,, I uh, l1u11h er.. p. 1-275 kllOI.N. k .• 1962. Sc1ni-qu.1u1i,a1hc a,ulpi, ol d1hu11tl ••r XI.I) ,laffr.ulloll \111 ~l,n rraloci11, w. 47. p. 1511-1592 •Sc110Mauac• •• II .. 11,1. u,e Jungh.1u-l1url11. in gculosiulicr 111111 ll1111 II \tl11 I ll111H1l11 Brr1bau1· Almanach lur E1tlLu11Jc, r ,c.7--tS~ S11u110, L .• 111d DIANNOC&, \Y. W .. l'lli2. ll,11id ~11•lr111 ul "'"·"· , ........... .,_ .... 1 ,., .. ., plialc rocb: II. S. Gcol. So.rr llull. lltl ,\. S6 p S11u11n, G. L~ \Yo1111.., J. l., anJ [wrNc;. M .• 19S6, Cr••"J mc•1u1e111,·1111 111 ,,,. \'11i;111 hlands: Crol. Sue. Aracrica bull. w. 6). p 15~15J6 REFERENCE NO. 11 ,. )) ·• ' .. i ' ISSN 0500-4780 CLIMATOLOGICAL DAT A ANNUAL SUMMARY PUERTO RICO AND VIRGIN ISLANDS 1987 VOLUME 33 NUMBER 13 "I CERTIFY THAT THIS IS AN OFFIClAL PUBLICATION OF THE NATIONAL OCEANIC ANO AT"OSPHERIC AO"INISTRATION ANO IS CO"PILEO FRO" INFOR"ATION RECEIVED AT THE UllONAL CLI"ATIC DATA CENTER, ASHEVILLE NORTH CAROLINA" ,-. 28801 -=-~~ C7y I") °' I , --7)..,,._,,_,<,J.., .,J./ .fi.Jt.r ~ noaa DIRECTOR NATIONAL CLI"ATIC DATA CENTER NATIONAL OCEANIC ANO ATIIOSPHERIC AOfllNISTRATION NATIONAL ENYIRmi'CNTAL SATELLITE, DATA ANO INf'ORIIATIOII SERVICE NATIONAL CLINATIC DATA CENTER ASHEVILLE NORTH CAROLINA ( ( TOTAL PRECIPITATION ANO DEPARTURES FROM NORMAL IINCHESI PU[RIO RICO ANO VIRGIN ISLANDS ------ ___ ...Lil.L STATION JUL AUG SEP oc T NOV DE -- C ANNUAL Pll(C IP D(PARIUR( PICC IP O{PARIUR( PR(CIP O(PARIUI( PR(CIP 0( PAR I UR( PR!(IP O!PARIURI PR(C IP O(PARIUR( PR[( IP O(PAR1UR! -~-- VIRGIN ISLANDS ST THONAS 01 DOROTHEA HS I .12 2. 7 2 2 . S 7 4 .Sl 1 8 . 4 7 4 4 ] ESTATE FORT NYLNER 2.0• 2. 71, .40 4 32 1 7 l 7 s .bS ESTATE HOPE I. II 2. 'lb 2 . '10 4 57 1 2 , 1 4 2 7 RED HOOK BAY I. 22 I. 1,'I I . lob l . , 1 11 4, 2 32 TRUNAN f"LD FAA AP . 'l'I 2. 4 I I .42 4. 35 10 )t, 2 ,, IIINTB[RG . '13 I . S 3 I . 4 3 3 . S l 10 4 l 4 1 l --DIVISIONAL DATA-------> I . 4Cl - I BS 2 22 - 2. )8 1. so . 4 1,0 4 1 4 . 1 2 7 1 l 1,2 B 5 I l 90 70 1 7 Al~ I, 7 1,1, 4 1 . J 7 l1MfV\. 42. 84 50. OB 1 2 53 9 7 1 0 2 J ~3--73/ ST CROIX 02 IILEX HIINILTON FLO F "" I . 22 - 2 . 1 4 I lo l - 2 84 2 7, - 2 84 2 bS - 2 .bO 1 ) 25 B 2 ) 4 94 9L 50 1 0 IINNIIL Y 2.21 I . ICl 2 . o, 2 80 1 S Ol l 52 58 1 I, ANNAS HOPE I . ICl • I • ._l 2 I . 25 - 3 1 2 1 .SO - 4 S l 4 1 0 . , 7 11 45 5 BbH BETH UPP[R N[W WORKS I . '12 I . 32 2 .02 H 2 .55 1 5 2 7 4 b 2 CHRISTIIINSTED FORT 2.21 . lb 1 . 4 l 3 78 1 5 48 l 7 l H 48 89 55 5 1 COTTON VALL[Y 2 2 so " " 3 81, 10 1 7 2 )9 E II ST HILL I .41, 1 . 1 l 1 45 s I 3 1 ) 80 l 1 9 [STII TC TH[ SIGHT 2.20 1 I 1 I 23 4 8 I, 1 4 5 I 2 9b FOUNTAIN 3.00 1 . 'II 1 . so l .00 1 5 .23 5 50 FREDERIKSTED I SE 2. 3 1 2 . o, 2 .'12 2 52 1 S 7b l 7 4 54 89 58 10 I, 1 I, 7 51, 75 GRIINIIRO 1 . S 7 I 45 I 1 8 3. I 7 H H HIIN BLUFF L-H STN I ,s I 1,2 1 . 4 2 " 2. l l 11, 95 2 H, NONTP[LLl[R 2.55 1 38 2. I 0 4 . I, 3 I l 7 8 4 42 59 02 58 7 8 - -DIVISIONIIL 011111-------> 2 .08 • I . I 7 1 52 -3.08 I 80 . 4 )0 3 . b B - 1 . 7 J 1 4 22 9 11 l 82 04 .,., 2 1 1 1 4 I ST JOHN 03 CANEEL BAY PLIINTIITION I . 7 4 2. 1 5 2. 2 l 5. 0 7 1 2 Bb 3 90 CIITH[RIN[BURG 2.02 2. 20 1 . 2 2 S . 2 7 1 l OB H 4 42 48 22 H 49 4 7 CORIIL B"' 1 . 7 4 " l.bS l.Sb 11 52 4 5 b CRUZ 811 Y 1 . S'I • 2. 11 2. 27 - 2. 0 2 2.42 - l. 55 l. 75 - 1 l 7 B 54 4 OlH [AST [ND 2. I 0 1. 18 2.01 ' l.08 1 0 l 't l b 7 40 b <' LAN[SHUR BAY 1. ,s I. '10 " " l.08 1 0 b4 4 04 --DIVISIONAL 011111·------> 1. II - I . 4 4 2.01 - 2. S 2 2. 3 2 · 3. 7 8 4 . 1 S - 1 . 2 b 11 1 7 b Ob 4 04 2b 4 4 91, 1 22 SH RCF[R[NCC NOICS FOllOW NG SI A 11 ON I NO( X STATION OUTL T IIUi ISLANDS 01 "ONA I SL ANO 2 Vl[QU[S ISLAND 12 --DIVISIONAL OA TA- - - - - - - > VIIIGIN ISLANDS ST THO"AS 01 DOIIOTH[A l[S 11[0 HOOK llf TIIU"AN FLO FU AP --DIVISIONAL DATIi- - - - - - - > ST CIIOII 02 IIL[X Hll"ILION fLD FAIi IINNIIL Y BETH UPP[II N[N NOIIKS CHIIISIIIINSl[O fOIIT --DIVISIONIIL DAIii-------, ST JOHN 0) CAIH[IIIN[BUIIG CIIUZ BAY --DIVISIONAL DATIi- - - - - - - > ( AVERAGE TEMPERATURES AND DEPARTURES FROM NORMAL l°Fl JAN FEB MAR ! i ? i ~ i - .. - ~ - i i - I ' I -.. .. .. Ill ~ * ~ "''5 1 1'5, 71, ) 1' 4 1'5. 11, s 1'5 7 1'5, 71, 3 " 7'5 I, 1'5 I, " ~ " 71 8 1, I 78 'I 71 3 I 1 11 8 I 2 11 s "711 3 11 8 11 , " " " " " 1111 I "11 8 71, I 11 711 I I s 11 ) 7 74 s -2 "74 ) "7'5 'I "7S I 1171 1 11 2 11 1 71, 0 I, 71, I, 0 11, 4 -- APR MAY ---- - ~ :, - - .. :, .. ~ - - - - a' - .. .. .. "' .. "' .. .. =i: - ~ 7'1 8 80 4 78 1 "'" s 7'1 8 80 4 78 1, 78 1 • " 81 1 81 4 JUN . ,--·-- - :, - .. :, -- - .. ~ "' " 1'1 I .1, 'I • 82 4 JUl ~-- ~ -- a' ; - Bl 80 83 "81 " 83 2 0 2 4 8 - ~ -.. .. .. AU(i 84 4 81 7 84 4 81 S BS 1 l BO 2 I 8 110 I l 81 2 2 82 b 8 8) 8 I 'I 81 ) • ' ~ 1 II l •1e l ... 0 8 7'1 1 80 1, 82 1, Bl 'I 11 " 11 " 11 11 " 11 " 2 , 10 I, 8 12 I, I 2 Bl 1171 1 "78 4 1178 'I 1181 l "82 1 1183 2 I ) 1 'I ':; l 80 1, e 81 1 ' Sil RIHa(ICI lllfS f0ll0III"' SIAIION INDII , 84 1 84 1 2 e 80 b 84 '> 82 b 1 Sf fl - :, .. -.. "' 83 4 81 'I 8) 4 82 2 85 I 8) I 84 82 84 3 83 <; 81 'I 83 8 82 'I .. :, -.. .. 0 2 2 1 l I '> 0 C I - => C .. .. "' eo 8 81 4 8 3 'I 82 1 83 4 112 8 Bl I 1'1 b 83 2 81 4 I 1 8 2 ., NOV l'I 0 78 'I 82 3 80 b 82 l 80 b 81 4 11 J 81 8 l'I b .. :, -.. A 1 3 J PU[IIIO 111(0 ANO VIIIGIN ISLANOS _..1~8.1- U[C - ~ C -!. 1'1 1 18 I I 'I 1 lb ':, 81 0 78 8 81 ll 18 <; 1'1 4 l'I I, lb } lb } ? -.. .. .. I ' ANNUAL - ~ 18 'I 82 0 80 b Bl ., 80 'I " 't l't • .. :, -.. .. .. I 1 2 '> I) REFERENCE NO. 12 ii . .! l , __ il.·_J .1_ .c'-.~,(_. ,~ l 1 I j - ; ; i 1 t ESTIMATED WATEH USE :N 311 THOMAS, U.S. VIRGIN ~SLANDS. JULY 1983 · JUNE 1984 a, ~eriberto Torres-Sierra ana Rafaei Oacosta - Prepared in cooperation with the CARIBBEAN RESEARCH INSTITUTE COLLEGE OF THE VIRGIN ISLANDS ST. THOMAS, U.S. VIRGIN ISLANDS DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY WATER RESOURCES DIVISION OPEN-FILE DATA REPORT 84-721 .=ST/MA TED NATER JSE iN ST. l/RGIN ISLANDS~ U.S. ~HOMA S. JUL'! . .983 )UNE 4 984 By Heriberto Torres-Sierra and Rafae, Dacosta iNTRODUCTION .:ater -~3e :ata : ,_;j ::r.cr:;.wai ~--"cur:-: Jrr.our.::s J ~as ~i·~·a\·s :t-:e :-'.csc ~i.rf::.-::uit -2iement ~e[::-:e :n :he ~~drc~~gic ~~:c _i:::. :::-:e :-eeci .eterr.ane ::~e a~ount cf water ~sed c~ ~eet ::uolic, -0~r.iercial .=.r.d ~omescic --.eeas J.;nong : ther ·1ses :s 2ssencial ~here :he available ::iupply is inadeauate. :n St. :'hor.:as, ·_·.s. ."irgin ~slands, ~.here streamrlow ,;ccurs ::iostl:: ~uring periods ~r intense rainstorms and ~rcund-water rescurces are limited (Jordan and Cosner, 1973), water-use information is critical. In l983, the l.'.S. Geolog- ical Survey, Water Resources Division, in cooperation with the Water Resources Research Institute of the College of the Virgin Islands, jegan a general- ized inventory of water use in St. Thomas. St. Thomas is located about 20 r.iiles east of Puerto ~ico (fig. 1). The island's popula- tion increased from 16,000 in l960 to □ore :han ~;,500 ~n 1984, paralleled with an in- crease in water production to meet the public •,1ater-s•..1pply demand (fig. 2). The water demands ;~ave increased also ::.n :espcnse to tourism development. ~lthough the production of water incre~s- ed with the installation of a :arge-scale ~eawater J~salin3- tion plant by the Covernmer.t cf the U.S. Virgin islands, the demand has not beet". satisfied. U.S. GEOLOGICAL SURVEY WATER RESOURCES DIVISION ·-ere: ..::1 c -:-.osc ... ·: -·..1e =.J ~~ai(.::1ge ~:-i ~:~e -,vstern ir:.sta.i.i.~d = r:.c .. ~..:sses :ror.i :istr::.but1on ir:. : 0 ~9 l~riede- -~,c.·,. 1ther ~0sses ,~re .,~e :.) ~:-.;.;uchorized connections, ,mcontrolled ,'fig. J). :·aultv ::ieters, cind ?UDlic :'aucets WATER SOURCES AND USES ~!--.e ?rincipal :oources ~nd uses of water in St. Ihomas are shown in :'ig. ... Seawater, rainfall collected ~rom residen- tial roof-cop catchments, and ground water dre the main water sources in the island. Thermo- electric-power generation, pub- lic-water supply, and domestic and commercial self-supply are the principal uses. Seawater is used indirectly as the source of condenser-cool- ing water bv the Virgin Islands ~acer and Power Authority (\./APA). The waste heat from the Island thermoelectric facility (fig. Sa) is used by the seawater-de- ~alination ?lane (fig. Sb). ~esalinated water from storage tanks (fig. Sc) is distributed to the urban areas in Charlotte Amalie (fig. 5d), oy the Virgin Islands ?ublic Works Department l \'IPWD). Areas outside the ?Ublic-water supply distribution ;,ystem, such as the Donoe housing ;,reject at ~ew, (fig. Se) can be classified as self- 3uppl!cd ~sers. 7he~e ·btain their water supply from rainfall catchments, ~ells, or from com- mercial water haulers (fig. Sf). ' ' \ I I t ·l i l • -:'~e ~ain ~~arlotte Amalie jv a .seawater :~,an drea )t ~s also served ,·:stem. :'his ,.:;•,stem suopiies · ... ·acer :or :ire :ighting and ilusn1ng of toilets .ind open drains. .~reas outside :he seawater svstem depend on grav water ~astewacer from ocher household •sses/ as their source water :~r :lushing tcilets or 1rr.gation. \Jhere aouifers ~1eld significant water :o wel:s :o gal,'C"in or :nore) :hese ,re also :apped as a source 0i ~acer, ~ven if saline. 3s ~eed ~or reverse Jsmosis ·!nits or tor flushing. oottled water ?reduced ~ocally Jr i~ported 1s an i~portant drinking water source. 3octled water ccsts approximate- lJ SI .25 per gallon. [n 1979 importation of bottled water was estimated at 1,600 gal/d (Peebles, '.979). There are no reliable figures for current imports. Publlc• W•ter Supply Production of desalinated water during the study period averaged 2.4 million gallons per day (~gal/d). Only about 0.9 Mgal/d (J8 percent) was accounted (revenues from sales) by the VIPWD. About 1.5 Mgal/d waa unaccounted for as previou ■ly indicated. A recent investiga- tion showed that leakage in the distribution system represents JO to -.o percent of th• total lo ■ses (CH2M Hill Southeast, 1983). The production of desalina- ted water for public supply increased to a peak of about 2.4 Hgal/d in 1975, declining thereafter to less than 0.6 Hgal/d in 1980. Since 1981, WAJ'A haa in■talled three n- de ■alination units with a total rated capacity of 3.1 Hgal/d. At pre ■ent only two units are bein& operated. Full production capacity will be required vben the East !nd Tranaatssion Sy ■t­ becOMs operational (fia. 6). Thi ■ distribution sy ■t- wa ■ constructed in 1977 but has not been utilized. Water puaped to tbe seawater distribution-sy■r- averagas 1.0 Mgal/d. Only about 0.35 Hgal/d of thi ■ a-,wt i ■ accounted for at th• public sewage treat111ent plant serviDI Charlotte Amalie. The reaainder may be lost through leak■ in th• seawater-distribution syst-. ~owever. :.:-:..:-:...:$ 5::.:-r-:::i : :- 3. ::.:is _,. 1:-e : c.e -.:harlott~ .::ai .. e continuous.·• : :~shed Jcean ~v :2:s ==-~~ =~~ s~awater- distr1but .. 0n s-.·sceo. )1scnarie from two 0t :~ese ~aps •ere ~easured and had an average r:cw of 0.08 ~:2ai1c! ~.ich. ,~ve these caps wouid account :0r of the unaccountea :low .. The c':'st vi to ~APA ::-om cne :.in its :.s 1:::,ouc thousanc c~ilans ?Otable -..acer oesaiinat .. on $9.00 ?er I S 9. 00 / kga i l . :'his dces c,oc .. :-.elude amortiza- tion costs er the desalinat:cn units (.-\Jav1 ~nd Gomez, l983). The actua.. c:ists charged c·, \'IPWD to c_,r.sumers connected to the distribution svsteo cs S14/kgal (',"lP\.'D personal communi- cation, '.?84). Tllermoe/ectrlc·Power G•n•r•tlon Thermcelectric-Power Gene- ration is the largest single 11ater use category in Sc. Thomas. Total use was about 67 Hgal/d. This was essentially seawater, except about one percent freshwater obtained directlv from the desalination plant for boiler feed. Do...■tlc Self•Suppl/ed • R•lnf•II About two-thirds of the population in St. Thomas is not served by the potable public water supply distribution systea, and thus classified as doaestic self-supplied. Rain- water collected fro• rooftop catchaent syateu and stored in cistern ■, and withdrawals fro• around water are the sources for doae ■tic self-supply. Estiaated water use for this category was about 0. 75 Mgal/d. Of this .-unt, 0.60 Mgal/d (80 percent) wu supplied froa rainfall. Thi ■ indicates that rooftop catclments are a major source of water for moat private hoaea eepecially in the more huaid area ■ of the island (fig. 7). Virgin Islands law requires all dwelling ■, aparc-nt1 and hotel■ to have a miniaua cistern 1tora1• of 10 gallon ■ for each square foot of roof area fer one atory buildings, and 15 gallona for each square foot of roof area for two or more story buildings. All other buildings ATLANTIC OCEAN ~ C Q 1ST. THOMAII 't Cul•~• ~~Jo iur uuL II: 2. Ill II. • z 0 ~ ~ ire recu:~ec to nave :~sterns •ith a m.1:11mum useaole capac1c·.· Jf -~ gallons oer sauare face Jf coo: area excepc churches and warenouses, which are not reauired cc conform to this standard (Jordan and Cosner, A comparison of yields !, '- .en rooftop-rainfall catch- ments at a high rainfall (Doro- thea) and at a low rainfall area (Red Hook), was made using data from July 1983 to June 1984. The comparison was sade for a family of four using 25 gallons per capita per day (25 gpcd~ with a roof area of l,DOO ft and an initially full cistern (10,000 gal). The faaily would have required the services of a water hauler only once if they lived in the Dorothea area, and twice if they lived ia the Red Hook area. Rainfall could have supplied about SO percent of the total water needs in the Dorothea area, but only 31 percent at Red Hook. The cost of water produced by household roof-top cistern systems is esti-ted at $17 to Sl9/kgal (CH2M Bill Southeast, 1983). The aajor cost is associated with con ■truction of a cistern. oo-•tlt: S•lf·S•Plllled • Ground W•ter Ground water withdrawn for domestic self-supplied use was about 0.!5 Hgal/d. Ground-water lrawal s by the Virgin :i..___,nds Housing Authority (VIHA) was estimated at 0.10 Hgal/d. An additional 0,05 M&al/d was used by other doae•tic self- supplied users. Ground water for domestic use is available in nearlv all parts of tne island, There are onlv a few areas where yields to wells are large enough to warrant the development of public supplies. Ir their study, Jordan and Cosner divided the island into five ground-water areas according to their poten- tial yield and water quality (fig. 8). The potential yield a::J •4~1:~ ~Lui_,.:. _;,. tnese area.s 3~e ~.:~1cec :i-.· 1?xcesa1ve depth __ .·acer, seawate~ intrusion, waste-water cc~camination, and contam1nat1or. froc seawater mains. Commercial Selr·Supplled Condominiu~s and hotels used about 2.0 Mgal/d of saline water. This is used principally for cooling. flushing toilets, and swi1D111ing pools, Small desalination plants produce abou: J. l !1gal/c freshwater. About 0.c Mgal/d of the comnierci~: ~acer-use is ground water. This is used mostly for flushing toilets. In •oae areas, where the ground water ts of good quality, the waste w•t•r is used for irrigation of lawns (Mahogany Run). However, most of the co1D111ercial facilities are located near the coast and pimp saline-ground water. Water haulers supplied an estimated 0.07 Mgal/d of de ■alin­ ated water from th• VIPWD standpipes to c □-ercial u•er■• The average price of water delivered by water hauler• i• S55/kgal (Ajayi and Golles-G6aaz, 1983). An estimated ■-unt of 0.05 Mgal/d was obtained froa rooftop rainfall catchllent•. Public W••t•·W•t•r Tr••tment There are sev•n public waste-water treatment f•cilitt•• in St. Thomas ( fig. 9). The airport plant, serving Charlotte Amalie, discharges about 0.5 Mgal;d to the ocean. Inscancan- eous flow rates measured in June 198, ranged from 0.16 to 1.4 Mgal/d (fig. LO). Specific conductance measurements indica- ted that about 70 percent of the effluent was seawater. The ocher six wa•te-water treatment plants serve mostly public-housing projects. These discharge about 0.20 Hgal/d to streans and the ocean. •Nfffl ..... T'. - _ _. llaa •• -• .... - ,.,._.. •us•• ___ ._.,,~ ................. - ., ..... , ........ ,,. -----= ~·.:;;·.:.-~- ,, .... t.i,-- - - -· ........,., :: == ~ .. !·:- -··-- ,. ·- •-· _..... _____ -·-·· • '""' h. ~-.. •- • - t• -" •••••u.._,.,. r,n11•r ., ,...,,._..,••'•"'• ,., ,,.. ,,.,,..,,,.,, nl water dl ■trlfu,,.~ SOURCE, DIS TRI F/GUIIE le. S••••t•t l•t•II• et tlle Tll•t•o•l•et,lc ,, ••• , ,,, •• , ., ,c, •• •• , ,s •• •••• ,. FIGUII• Id. D••••tlc ••d co•••tclel ••• , • ., Cllerl•U• A••II• erea. t EXPLANATION CJ Area Hrved a 3 • MILES ■ Ptpellfla lnetalted IMlt not -••'-• .. of Jul,., ..... □ A, ...... , -,,eci FIGUIIE e. Ai••• ••,.•d •r tll• tr•••·••t•r dl•lrl••tion •retem. FIGUIIII T. A••t•fl•••••••I rol•tell, I• l•c•••· (l'r■-■rod •r 11.J. C&lff_,, lllW•J IIOAA.) ! 801 (C lo L FIG ' - REFERENCE NO. 13 ; ! i •I._.'\. - DATE: 'stJaJECT: FROM: TO: THRU: ·-· - UNITED STATE::, ENVIRONMENTAL PROTECTION A~cNCY JAN 06 see REGION" Preliminary Assessment and Confirmation of ~uthorization of CERCLA Removal Action Monies for the TUTU Well Site, Anna's ~etreat, Saint Thomas, u.s. Virgin Islands - ~CTION MEMORANDU~ Carlos E. O'Neill ~ ~ r,· On-Scene Coordinator ~ct~""-J I., Stephen D. Luftiq, Director Emergency and Remedial Response Division George H. Zachos, Acting Chief Response and Prevention Branch I. EXECUTIVE SUMMARY On July 1S, 1987, Mr. Allan Smith, Commissioner of the Department of Planning and Natural Resources (DPNR), u.s; Virgin Islands, verbally requested that the u.s. Environmental Protection Agency (EPA) provide analytical support in the sampling of one well which was reported to exhibit a strong unpleasant odor. This well is a major source of co■■ercially provided potable water supply for the eastern portion of St. Thomas. The well is located on the eastern part of the island in the Tutu Section of Anna's Retreat./ This verbal request was followed by an additional request for EPA to assume the role of Lead Agency after sampling result• indicated that several commercial wells were found to be contaminated with hazardous substances. This verbal request was followed by a formal request in writing by DPNR on August 10, 1987. - In July and August of 1987, EPA confirmed by sampling and analysis, the contamination of groundwater with volatile organic compounds. A major contaminant in the groundwater is tetrachloroethy~ene (TCE). The EPA 10-Day Health Advisory Level of 175 ppb was exceeded in three (3) of twenty four (24) wells sampled, with two of the three contaminated wells being private residential wells • ./ The concentrations found ranged from 240 to 7,600 ppb with seven (7) additional wells being below the EPA 10-oay Health Advisory, but above the o.s. Virgin Island's interia ■axi ■ua permissible concentration levels set on Septeaber 1, 1987, by DPNR for volatile organics in drinking water in the Turpentine Run Aquifer (50 ppb for a single com- pound or 100 ppb for total volatile organic co ■pounds). Three of the previously ■entioned seven well• were residential wells. lLJ i Ut.;l RBalON II FOIIM 1320-1 (9181) .. ·:• i .,c. -.. :, .i. - -2- This ~ction ~emorandum will document funding authorizert for Phase I of the Tutu Well Site Cr.~CL~ ~P-moval ~ction. P~ase I addresses only residences having contaminated drinking water wells with volatile orqanic compounns above levels established by the u.s.v.t.'s interim maximum permissible concentration levels for potable water. This action di~ not include wells where water is used prim~rily for commercial, business, industrial and/or trade purposes. It also dirl not inclu~e wells contaminated solely by gasoline or gasoline by-products which are not hazardous substances within the definition of section 101(14) of CERCLA. This action includes the decontam- ination and cleaning of residential cisterns contaminated by hazardous substances, the modification of plumbing, the delivery of water by tank trucks as a temporary alternate water sup~ly, and a well water monitoring progra•• The total project ceilinq authorized for a 52-week period is Sl00,000 of which $40,000 is estimated for mitigation contracting, $45,000 for TAT's extramural costs; and S15,000 for EPA's intramural costs. This memorandum will confirm your prior verbal authorization of Trust Fund monies, issued to the Chief, Incident Response and Prevention Section on September 1, 1987, to initiate the removal action at the subject site, and subsequently revised to the current project ceiling of $100,000. II. BAC1CGROUND A. Historical Information A request for EPA analytical support for one well in the Tutu section of st. Thomas was made verbally on July 15, 1987 from DPNR. on July 31, 1987, a verbal request for EPA to assume the role of Lead Agency was made, and this was followed bv a written confirmation of the request, dated August 10, 1987 (received by the Emergency and Remedial Response Division on August 19, 1987). The initial request was based on a report that one well was reported to have a strong odor, characteris- tic of a petroleua product. Thia well is a major source of comaerciallyJprovided potable water for.the eastern portion of the island. •SPA'• preli ■inarv investiqation co ■aenced on July 21, 1987, with a field reconnaissance and sa■pling of this one well and ■ix additional wells identified in the ia ■ediate area. several of th••• well• are also major water suppliers of public drinking water to the ea ■tern part of the island. \ \ J \ -3- Laboratory results from this survey indicated that the initial well was highly contaminated with gasoline and chlorinated organics, and the additional six wells contained elevated levels of chlorinated volatile organic compounds. qased on these results, OPNR declared that an imminent health threat existe~, which could affect approximatelv 20,000 people living in St. Thomas. In addition, an indefinite number of tourists who vacation in St. Thomas were at risk since these commercial wells supply water to major hotels and restaurants. DPNR issued orders to close these seven commercial wells to protect public health. ·/subsequent to this action, ~PA expanded their sampling plan due to the threat of greater contamination to drinking water wells in the area. EPA along with OPNR, identified other wells within the Tutu Water/Turpentine Run Aquifer which may be impacted by the hazardous substances identified to be pres- ent in the groundwater. A second round of groundwater well sampling took place on August 10 and 11, 1987, which included a total of twenty-four (24) wells identified in th• Tutu Section of Anna's Retreat. All twenty-four wells were sampled and analyzed for volatile organic compounds. Pollowing these results, DPNR ~losed the five private wells which service two three-family homes and one apartment building housing twelve studio units. B. Site Setting/Description The contaminated wells are located in the Tutu Section of Anna's Retreat, St. Thomas, u.s. Virgin Islands. The five (5) private wells recently ordered closed are located in the Tutu residential area. At the present ti ■e, the affect•d area is not serviced by any public water supply. EPA sa ■pled a total of twenty-tour (24) wells in the Tutu area and found five private wells and eight (8) co ■■ercial wells s•riously conta ■inated with up to 7,600 ppb of PCB. (Se• ■ap attached). c. Quantity and Typ• of substance Present EPA sa■pl•d and analyz•d for suspected volatile organic com- pounds on July 22 and August 10, 1987. Listed b•lov ar• the maximum conc•ntrations of the hazardous substances identified in the drinking water wells: TUI 2315 Contaminant Tetrachloroethylene Trichloroethylene Benzene -4- Maximum Concentration Found ( ppb) 7,600 61 1,400 Statutory Source of Hazardous Substances under CERCLA Clean Water Act section 307(a) Clean Water Act section 307(a) Clean Water Act section 307(a) The results ot the sampling are contained in Tables I and II. PCE contamination ranged from non-detectable to seven thousand- six hundred parts per billion (7,600 ppb). sampling results adequately document 3 wells with contamination above EPA's 175 ppb PCE 10-0ay Health Advisory Level and eight (8) wells above the OPNR's interim standards for maximum conta ■inant levels of volatile organic compounds in drinking water. III. THREAT A. Threat of Public Exposure Direct contact with PCE may cauae eye and no ■• irritation along with dry scaly and fissured dermatitis. Acute expoeure through absorption, inhalation or ingeation, may cause central nervous system depression, hepatic injury and anesthetic death. PCE has been found to be carcinogenic. Thia is a ease of actual contamination in exceaa of the EPA 17S ppb PCE 10-oay Health Advisory Level for a three-family house and one apartment building housing twelve studio units. In the other three faaily apartment dwelling ■, the well con- tamination exceeded the inter! ■ DPHR drinking water standard of 50 ppb for any single volatile organic constituent. In addition to the exposure via consumption of the water, or eating food prepared with thia water, showering with water contaminate4 with volatile organics can contaainate the air to significantly unhealthy levels. fLIT (.l() J -5- The location, direction and di~ensions of the plume are af- fected by variations in water table depth, r~te of punping of the wells, duration and intensity of rainfall, and inter- mittent releases of chemicals from one or more sources, all of which are unknown at this time. Given the above variables which affect contaminant strengths in any well within the plume may vary randomly. On September 2, 1987, DPNR issued three (3) orders to close wells and issued two (2) advisory letters to homeowners not to use well water for drinking, bathing and washing. B- Evidence of Extent of Release Investigation, sampling and analyses by EPA have identified contaminated groundwater, as described above, and containing contaminates, as described in Tables I and II. c. Previous Actions to Abate Threat No mitigative action was taken by any Potentially Responsible Party prior to EPA's recent activities. o. Current Actions to Abate Threat JEPA haa comaenced an investigation of the TUtu Water/Turpentine Run Aquifer by establishing a cooperative agree ■ent with the u.s. Geologic survey to define the characteristic• of this aquifer and to determine the extent of conta■ination. EPA and DPNR have also co ■pleted Aquifer and a monthly well monitoring program is being developed • .J DPNR haa issued a total of ten (10) orders/advisoriea to well owners to cloae sixteen (16) wells. A local dry-cleaner ha ■ been identified as u ■ing and storing PCE. Handling, storage and dispoaal practice ■ fro■ thi• facility are unknown at thi ■ ti••• DPNR ha ■ propo ■ed to issue an adviaory to local dry cleaning establiahmenta inatructing the ■ to properly ■tore and hold all waste for proper diapo ■al by an induatrial vaate hauler. JoPNR with the aaaistance of EPA is conductin9 &D aaae ■■■ent of at least nine (9) facilities identified to b• potential sources of hazardous vaate and/or substance rel••••• in the Tutu area. iUT 001 2S1/ -6- has cleaned the homeowner's cisterns that have been conta~- inated by hazardous substances from the groundwater, modified the existing home plumbing to terminate well connections, and intends to continue to deliver clean wat~r via tank trucks on a regular basis, and establish a surveillance program for all wells in the area by a monthly groundwater monitoring program. This Phase I, short-term removal action will mitigate the threat to public health by providing a te~porary alternate source of water for affected consumers. IV. ENFORCEMENT The contaminant plume is generally believed by both DPNR and EPA, to ·have its source from past and present improper handling and disposal practices of organic solvents, possibly from dry cleaners and auto repair shops operating in the area. This site has been referred to the Site compliance Branch for enforcement action. An attorney and enforcement project officer have been assigned to this case. EPA issued Request for Information letters to all Potentially Responsible Parti••• v. PROPOSED PROJECT A. Objective of the Phase I Reaoval Action ~- The primary objective of the Phase I of the re ■oval action is the mitigation of the threat to public health by providing a safe potable vater supply to the affected re ■idences. Two three-family ho ■es and one apartment co ■plex housing twelve studio units vere identified•• being dependent on groundwater fro ■ their own private wells. Their respective wells were ordered closed-down by DPRR for exceeding interim drinking water standard ■• To reach the objective of providing a safe interi ■ drinking water supply and protect the health of the public at risk, the following re ■oval action was initiated. Water storage cisterns, which received conta ■inated groundwater fro■ affected wells, were cleaned and sanitized. Cistern ■ were filled with clean, safe, driuia9 water. Water tank truck ■ fro■ local water haul- ers will be providing water for the affected cistern ■ on a reg- ular basis. Plu■bing ■odification was ■ad• to disconnect water line ■ fro ■ the contaminated well ■ which provide groundwater to the cistern ■• IUi -7- An attempt to connect well water directly to toilets for flush- ing will be made, if physically and economically feasible. A well surveillance program will be implemented involving all the wells in the Turpentine Run Aquifer, thru monthly sampling and monitoring. The longer term, Phase II objectiv~ will require the provision of a permanent alternate water supply in lieu of the temporary trucking of water to the threatened consumers within the plume area. Upon completion of an analysis of the alternatives for permanent water supply to these residences, a recommendation will be made for Phase II. B. Project Estimated costs Water consumption per person per day on the average is thirty (30) gallons. It is estimated that the one apartment building ,. has twelve studio units with the average of two people per unit. The two other private homes are three-family dwellings with the average of ten people in each. The cisterns in the three family houses are small and, therefore, a supply of water mu•t be deliv- ered every two or three weeks, respectively. The delivery period is currently estimated to be one year or when a permanent alter- nate water supply can be provided, whichever occur ■ first. PROJECT COST (PHASE I) Cisterns Clean-Up: Provide labor, material and equipment including one vacuum truck, pressure water spray guns, water tank truck, etc., to drain and dispose contaminated water and to clean and sanitize identified cistern•••••••• $13,000 Modification of plumbing including Labor and Material•••••••••••••••••••••••••••••• $ 5,035 Refill ci ■tern ■ with clean and safe drinking water••••••••••••••••••••••••••••••••••••••••••• $ 2,665 Provide cistern ■ with clean and safe drinking water on regular ba ■i ■ according to a pre- approved ■chedule••••••••••••••••••••••••••••••• $15,000 Contingency (101) ••••••••••••••••••••••••••••••• $ 4,300 Total Mitigation co ■t••••••••••••••••• $40,000 TUI .,;~ .::: • .1. '··/ -a- Extramural TAT Cost TAT Monitoring and sampling program (Including travel and per ~iem) ••••••••••••••••• $35,000 TAT Technical and administrative support (including travel and per diem) •••••• ••• $10.000 Total TAT Cost Intramural EPA Cost $45,000 (Including travel and per diem>••••••••••••••••••SlS,000 ESTIMATED TOTAL PROJECT COST •••••••••• s100,ooo This figure represents the estimated total for Phase I. It could be reduced significantly, if a reliable and permanent alternate water supply is found sooner than the proposed 52-week ■ delivery period, might be increased, depending upon the identification of new drinking water wells found to be contaminated with hazardous substances within the affected area. c. Project schedule Project initiation of cistern clean-up and safe water de- livery ha ■ already been implemented based on verbal funding authorization. Safe water delivery period is currently e ■tiaated not to exceed one year or when a permanent alternate water supply can be provided, whichever occur ■ first. V. RECOMMEHDATIORS Condition ■ at the Tutu Well Site meet the require ■ents of section 300.65 of the Rational Contingency Plan (HCP) for a CERCLA/SARA re■oval action. EPA ha ■ deterained that there is a threat to public.health at the site (Section 300.6S(b)(1 ). Thia deteraination va ■ baaed on: 1) R- ■ ezpo ■ure to unacceptably high level ■ of acutely toJtio ■ab ■tance ■ (Section 300.65(b)(2)(i), and 2) coataaination of drinking water supply (Section 300.65 (b)(2)(ii). \\J\ -9- The resident population at risk currently relies on crivate well water•• their source of potable water. This removal action complies with Section l04(b)(2) of CERCLA, as amended by SARA, in that it is consistent with the efficient performance of long-term remedial measures, by providing an interim supply of potable watP.r to the public until a permanent water supply can be secure~. This is a written confirmation of the initial and revised verbal approval of up to S100,000 for the total project ceiling estab- lished on September l, 1987, by the Director of the Emerqency and Remedial Response Division to the osc for the CERCLA removal action at the Tutu Well Site. The mitiqatinn contracting ceil- ing is estimated at $40,000, with an additional $45,000 for TAT costs, and S15,000 for EPA costs. Your authority to authorize these funds is pursuant to Deputy Administrator Alvin Alm'• memorandum of oeleqation Nuaber 14-lA dated April 15, 1984, and Richard Dewling's Redelegation order R-11-1200.6 of August 29~ 1984. ,. ~ . ., ' I .J APPROVAL: ~'S:{- u. Le,,µ,~ ___ __,,__ _________ ,,.._,+-- DA'l'Es I DISAPPROVAL a cc: (after approval i• obtained) c. Daggett, 2RA R. Salkie, 2ERR-DD s. Luftig, 2ERR G. Zachoa, 2ERR-RP a. Sprague, 2BRR-RP J. Czapor, 2BR~D-SC G. Pavlou, 2ZRRD-NYCRA I .. . . . . .. - DA'l'Zs J. Mar ■hall, 2OZP P. Gelabert, 2CPO R. Gherardi, 20PN-PIM 'I'. Sullivan, P~-214P (EXPRESS MAIL) T. Pielda, WR-5488 P. McEechnie, 2IG rur ,:.)() .1. • ~ r l PHOTOYAC llMPLIMG RESULTS TUTU IILL IJTI IT. 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I I •'• ' 11 .,. ' II .t. 1 . .,. • 141 .,. • . .,. II ,,. .,. II .•. ,. I .. ,. • (_·;!_) 1. \UI • J ~ .\), ~ r,:\_ tll Location C • Bryana ta.) ;....,. Rodr lguezC,) . Harthaan U) i:.-, • Eglin l3) ~~' Harvey l•> , ~teele (.1) ~ Nap: 7. Natblaal,a) 13.-VIHA~2.) 19. Lockhart,-...,..---.:: 8. S■itb U) 14. lAonardl') _,..,·,:ttet.. 9. rrancoi• l•) 1~. De■itri ~) ~\1 ... -~-~•:rfj 10. Tillet L•) 16. Dench ~) ,_)-t~•«: 11. R••••Y \! l 17. Devcon b) CQJlkawti."Ti=l) 12. 4 Winds 11 \z.) 11. Dede \1) ~tte:A. ••• () NUM~ta 'f Nt\\s••.::•: ''''''''''"'",__,, ,,,,,...___,,,,,,_,,,..., ----- REFERENCE NO. 14 r-:. ,l ' I U. S. Geological Survey Water Resources Division Caribbean District Open - File Report A SURVEY OF THE WATER RESOURCES OF ST. THOMAS, VIRGIN ISLANDS UNITED STATES DEPARTMENT OF THE INTERIOr n_: 1 001 ,. ;,,'.h IN COOPERATION WITH THE GOVERNMENT OF THE VIRGIN ISLANDS OF THE UNITED STATES ◄ . .;ssTRACT St. T~omas, w1thanarea of 32 square miles, 1s the second largest of the Virgin Islands of the United States. The island is :-:iOUnta1nous, and slopes commonly exceed 3 5 degrees· along a ::entral ndge 800 to 1,200 feet high running the length of the island. Toe general appearance is a panorama of numerous steep rnterstream spurs and rounded peaks. The island is made up of rocks of Cretaceous age, mostly ·,olcamc flows and breccias. A thin limestone and tuffaceous wacke complete the sequence of major rock. types. All the rocks have been tilted and dip about 50 degrees north. Water in Charlotte Amalie, the capital, is supplied by sea-water desalting and water barged from Puerto Rico and is augmented by hillside rain catchments and individual roof catch- ments. Rainwater augmented by water hauling and a ff!IW wells is the source of water for the rural area1. Streamflow is meager--2 to 8 percent of the annual rainfall-- and is predominantly storm runoff. Runoff after rainstorms seldom exceeds 5 percent of the rainfall. Runoff is rapid, however, and flash floods occasionally occur. Test drilling has shown that water can be obtained from fractured volcanic rocks in nearly all parts of the island. Wells will yield, generally, less than 1,000 gpd ( gallons per day). In the upper Turpentine Run Valley and the Lovenlund Valley, short- term yields of individual wells are as great as 100 gallons per minute. Estimates of potential yield from these areas are 300,000 and 100,000 gpd, respectively. Two smaller areas--Long Bay and Lindberg Bay on the outskirts of Charlotte Amalie have estimated ground-water yields of 70,000 and 30,000 gpd, respectively. Fully developed,. the surface- and ground-water resources of the island could yield 1 • 3 million ga lions of water per day. Ground water is slightly saline, commonly containing more than 1,000 milligrams per liter dissolved solids. The principal source of the minerals is bulk fallout of sea- and land-derived dust from the atmosphere. Solution of minerals from the rocks of the aquifers is the second largest contributor. Nitrate and some of the bicarbonate content of the water is probably derived from vegetation and animal and human wastes. Surface water is similar 1n mineral content to ground wa.._ during base flow. (}{) 1 - ,.. - UNITED STATES DEPARTMENT OF THE INTERIOR Geological Survey Canccean D1stnct Open-File Report A SURVEY OF THE WATER RESOURCES OF ST. THOMAS, VIRGIN_ ISLANDS by D. G. Tordan and O. T. Cosner Prepared in cooperation with the Government of the Virgin Islands of the United States l 9 7 3 I U I ,: l U . L .,::: .:::, :,.' :.:-; i ;. SURVEY SF THE 'NATER RESOURCES OF S T . :' H O M A S , ·; I R G I N : S L;,, N D S cy D. ,... u. fordan and C. T. :0sner LOCATION AND GENERAL SEfflNG Location The Virgin Islands. fomung part of the Antilles Island Arch separaung the Canbbean Sea from the Atlantic Ocean. are about l, 400 miles southeast of New York and almost l, 000 miles east southeast of Mlami. St. Thomas, the northwestemmost island. lies about SO miles east of Puerto Rico ( flg. 1 l. St. Thomas is the second largest of the more than 50 islands and cays constituting the 111rg1n Islands of the United States. The island 1s approxunately 14 miles long and 2 to J miles w 1de and has an area of 32 square miles. Lying within a few m1lea of the coast are nearly -10 sma Uer ts lands, ranging 1n area from slightly less than a square mile to a few hundred square feet. OCEAN ~··- I , .. _ .... ~ PUERTO RICO i I I -·-· 1 I CARl88£AIV S £ A . ·• " , ........... ·• •• .. .. _ ! -1r•,o· ... . , ...... .... ···-· ···- ·- ..... Figure l . --Location of the Virgin Islands of the United StatH. r \.J r \)!._) "i. Population .3t. Thomas has about 17,000 permanent res1- :::!ents ana a transient population of tounst and 1m- ::ortea laoorers of about 8,000. _;-:e ma1or1ty ot ::-.e cooulat1on is urban--aoout 20,000 people live .:-. -:::.arlotte Amalle. the only city and also the 5eat of ~overnment of the Virgin Islands. The ::ermanent populauon 1s increasing rapidly and 1s expected to double by 1980 ( unpuohshed data, : . ; . ?lanmng Board, 1964). Topography The land surface 1s almost enurely sloping and extends seaward from a central ndge, 800 to l, 200 feet h1gn, runrung the length of the island. The slopes, wh1ch common.Ly exceed JS degrees, are a1ssected by numerous stream courses of steep ;rad1ent. The general appearance is a panorama of steep 1nterstream spurs and rounded peaks. Flat land 1s confined to the Charlotte Ame.lie area and a few small a.lluvtal-hlled embaymenu. The only variation in the general topography is 1n the upper valley of Turpentine Run 1n ea stem St. Thomas. The valley has relatively gentle topography consUt1ng of rolling hills in a basin surrounded by steep slopes and sharp ridges. Land Cover and Use At one time almost all the land, including that charactenzed by steep slopes, was under cultiva- tion, prunanly for grazing or growing sugarcane or cotton. Agriculture, however. ha• declined almost to ext1nci1on. A few square miles of land are sull devoted to graZing in the east.-n part of the Island. and about 10 acres are used for truck garderung 1n the north cennl put. The remainder has been allowed to revert to bNsh and secondary forest. Now, land use 18 cblu191n; rapidly, much of it brought on by the Jet eve end its rapid men trans- portation. Increa ■iDJ population, 1n part caused by development of tlle 1 ■1Alnd as a retirement haven and by tourism , reaulb in more land being used for urban and suburban development. The increase 1n population not only makes new demands upon the water supply, but also the changes in land use could very well affect the available quantity and quality of the water resources • 2 ,.:li.mate 7he average annual rainfall 1s about 45 1ncnes 3nd the average temperature 1s only 80°F. =:ut the preva1hng 1mpress1on of the cl.mate 1s one oi dryness. especially 1n the winter. 7h1s 1s espe- ~iaHy true of the east end of the island, where, because of orographic effects, rainfall 1s only about 80 percent of that elsewhere. Rain 1s seasonal. nearly half falling between August and Novemoer. February and March are the driest months and September and October tne wettest. Most of the rain occurs as short, intense showers lasting but a few m1nutes. Ra ins exceeding 1 inch, with accompanying overcast, cloudy skies, come but six or seven times a year. Thus, there are few days when the sun does not shine. Although major rains are rare, their volume 1s noteworthy. The greatest rainfall of record was 18.0 inches September 13-14, 1928, dunng a humcane. The last great rain 1n recent years was 10. 6 inches May 8, 1960. the result of a stationary tropical depreHion. Th• island ll•• in the path of hurricanes and occasionally receives hffvy rains and high w1nd1 from pauing storms. Th• incidence of direct hits is low--demaginQ storms having a frequency of about one every 33 yffrs. The last humcane to cause extenatve damage was in September 1928. Th• direct rays of the sun are very hot, but air temperature is modified by the almost constant trade wtnd. Air temperature ( table 1 l ranges from a mean low of 72 .o• Fin February to a mean tugh of 87. 8• F ln August. The highest dally temper- ature of record was 95• f and the low, 63° F. The prevailing wind direcUon u from the east. Northeast and southeast winds are relatively common, but west winds are rare. Monthly average wtnd velocity during 1953-58 at Harry S. Truman Airport 1s given in table 1 • A wind rose for the same penod is shown in figure 2. Relative humidity is high owu1q to the proxiauty of the sea. At Hany S. Truman Airport dunng 1953-58 relative humidity was highest, averaging 81 percent,in the early morning hours, and lowest, averaging 66 percent, in the early afternoon. Average daily humidity is given in table 1 • r i' r I •. 1 I .I ,, I ( ( ( ,-----,-----------,-----------------------.----------------- --- -- --------~------... 1e•2s •••ao' .ATLANTIC OCEAN ~ AIRPORT CARIBBEAN SEA 0 a , •iln Groo111c TIIOICII rock• ' ,0 '< . <,S' o>C,- -P,.;... ... ,,. GeoloQr Qeoerol11ed oiler T W Donnelly, 1960 •• ( / EXPLANATION ALLUVIUM-Silt, clo~_. and thin, discontinuous beds of sand and gravel Includes beach sand. Estimated maximum thickness 50 It TUTU FORMATION - Tuffaceous conglomerat1c mix lure derived from older rocks. Contains some limestone, especially near the top Maximum thickness greater than 6,000 ft. OUTER BRASS LIMESTONE- Thin-bedded siliceous limestone and a few thin beds of tuff. Estimated maximum thickness 600 ft. LOUISENHOJ FORMATION-Woter-la1d tuft, brecc10 1 and a few thin beds of limestone Maximum thickness known 13,000 ft WAT ER ISL AND FORMATION-Lava flows, flow brecc1a 1 and water -laid tuff intruded by dikes and plugs. Maximum thickness greater than 15,000 ft Contact Inferred fault, dotted where concealed Figure 3.--0eology of St. Thomas. ( Geology :-!ie general geology of St. !'::.oma s l ::; • 3 1 :-:as :::een stuci1ed for :nany years. but only recently ::ave the geologic format1ons been named and :iescnbed ;n detail ( DoMelly, 1960, 196 6 l. 7::e ::ames of ;eoloq1c for:nauons used 1n this report :ire after Donnelly. 7::e names :,ave r.ot oeen adopted cy the U.S. Geological Survey. :'!ie volcanic and sedimentary rocks of St, Thomas are of Cretaceous < and older?) age. :'!ie ~ldest rocks, those of the Water Island Formation of Donnelly ( 1960 l are predominantly lava flows and flow orecc1as deposited at great depth on the sea floor. Uplift and subareal eros1on followed depos1uon. The Louisenhoj Fonnat1on overlying the water :sland Formauon was extruded from a volcanic center probably sited in what 1s now Pillsbury Sound between St. Thomas and St. Tohn. ~ear the presumed locauon of the volcaruc onfice the rocks are mostly very coarse reworked cone debns. Farther from the onhce, coarse matenal lessens and tuffs predominate. Near the base of the LouiSenhot Fonnat1on is a conglomerate composed chiefly of rock from the Water Island Fonnat1on. The Outer Brau Limestone was deposited on the flanks of the Lou1sennoj volcaruc cone dunng a penod of volcaruc qwescence. It consists of 200 to 600 fNt of thin-bedded graphiUc s1lic1f1ed radiolarian lunestone and a small amount of included tuffaceous matenal. The Tutu Fonnat1on, the youngest rock exposed on St. Thomas proper,u composed almost ent1rely of angular debns denved from the Lowsenhoj Fonnauon and minor limestone debr1s from thin limestone deposited contemporaneously with the Tutu Formation. The rocks were subaequently tilted to form a northward-dipping homocUne. Dips range from l 5 to 90 degrees and av .. 9e about SO degrees. Locally the formauou • .,. overturned. The permeable zone• that these rocks once may have had after depoI1t1on have been destroyed by metamorphism or by depo11t1on of minerals in pore spaces. Ground-water movement u now llmited to openings along joints and fault zones. The homoclinal structure 1s cut by sets of faults trend- ing N 45° W, N 55° E and north. Three well- defined Joint sets parallel each of the major fault 6 d1recuons. :'!'le valleys of the island nave similar :rends and are apparently the result of select1ve erosion of rock weaitenea by faulting and I 01ncng. ?n:ne zones of ;round-water ava1lab1llty, :hereiore, :ollow the valleys. Small alluvial deposits ranging from ?leiStocene ( ?l :o Holocene 1n age ue 1n tne •✓alley of Turpentine Run 1n east-central St. Thomas anci the larger coastal embayments. !'!ie alluvium of Turpentine Run Les in a narrow :,and seldom more than 200 feet 1n width along the stream. ~l!ax1mum thickness of the alluvium 1s about 40 feet. Most of this alluvium, which is composed of silt, fine sand, and clay and contains discontinuous beds of sand and gravel 2 to 3 feet thick, hes in the Mt. Zion-Tutu area of the upper basin and 1n the narrow valley from Mariendal to Mangrove Lagoon in the lower basin. The alluvium extends out under the lagoon near the !'TlOUth of Turpentine Run. Although com po sea pre- dominately of fine-grained material. the alluvium readily infiltrate• streamflow when the ground- water level 1s below the base of the stream. As such, the alluv1um forms a readily rechargeable aqu1fer, although it is of small extent and yield. Some ccaItal ambaymentI headed by interma- tant streams cont111n small deposits of alluvium 11m1lar to that of Turpentine Run. Maximum thickness of these depoIits 11 esumated to be SO feet, and their areal extant seldom is greeter than a few acre ■ ( an excepuon being the .Long Bay and Airport areas near Charlotte Amalie l. Near the sea, the alluvium 1nterf1ngers with calcareous sand and at Um•• contatna lenIes of mangrove- swamp deposiu. Therefore, the deposits are of minor s1gruf1cance as sources of water. OCCURRENCE AND MOVEMENT OF WATER Water move,: through a cyclic pattem--the hydrol091c cycle--1n wluch there are three storage areas : the sea, the land, and the atmosphere. On the land, surface water and ground water depend on: ( l) the amount, 1nten11ty, and areal extent of the rainstorm•: ( 2) the slope of the land: ( 3) the moisture content of the soil and vegetal cover; ( 4) the infiltration capacity of the soil and underlying rocks: and ( 5) the size. ! Ll I 1,Ul " ::umoer. and .::tercoMecucn :i Jpenings ... ::-:e 3quirer. ~-3Ln :s '.he ;r.:y :1atur3i source :t :resn water rec1enisn ,::e water ~eso1.:rces :1 ::-:e ,siana. "a:nfall :s seasonal.·.-:.::-, :he r3Lny ::e3son ::: .3te summer ana early iaU ::1na ::1 seconaary •,;et season usually Ln May. ::eariy nalf the r3in ialls ~unng ,:,ugust-Novemoer 1 :q. 4 •. Ka1ns exceea- :ng l ,ncn Ln 24 hours come SL'< or seven t::::es a 1ear. Four to 15 inches of rain ialls :n ::1 48-hour ;::enod aoou: once every 2 ·,-ears in large storms. :-~ese rains can occur 1n any month but are :nore '.ikely during the nurncane season I August- ::ovemoer 1. .:.bout nalf the ume annuai raLnta!l LS ::;etween 40 ana 50 inches I i,g. S l. :.ass tnan l•J :ercent of the time annual rainfall 1s less tr.Jn .i5 :ncnes. ·.vnich usuaUy means a maJor aeilc:ency :fonng the normal wet season and drougnt. The cumulauve departure from average and the 10-year running average of rainfall shown 1n figure 6 shows that at this time of wnting ( 1967) the island may be entenng a period of deficient rain- fall. With the exception of a few years in the late 1940's and early 1950's, rainfall in the past 30 years has been below average. There has been a long-term decline of about 10 inches 1n aMual rainfall since the peak of the surplus rainfall penod 1 n the early 19 30 's. The most severe drougnts of record occu1Ted 1n 1964 and 1967, wnen but 27 and 24 inches of rain fell. respec- tively. .:.real distnbuuon of long-term rainfall, shown 1n figure 7 ( see letter "a"), 1s controlled by topo- graphy and the prevaillng easterly to northeasterly winds, However. individual storms may or may not show the effects f')f oroqraph1c control or pre- ·,aihng winds and the areal dutr1buuon of the storms can be very in'9gular ( fig. 7--letters "b ·• to "f "l . Soil M 01 s ture The soil zone over most of St. Thomas is not :nore than 1 foot th1clc. Where of sufficient thick- ness it has. however, the un1que property cf absorbing large volumes of water--as much as 12 inches in 24 hours ( R. Scott, SCS. oral commun., 6 1963.. ::,;<aminauon .:::r ::.e sod ;:or.e ·,;r.e!'l :~: snC\Ys 1~ :: .:e ~~arseiv ..;r.Jr.i.;".3r ~·.-:::--:..; :.: .::_;;-.::- ..--.g :: ::::av .:1na s:lt :arucies. =~:)lcr..:::ea sa,'..;ra- :ion :s :-:ecessar1 :::e!ore ::-:e .;r3nuies crea,c -.::own. :s a result, ::-:e .;;ct -:as ci .--.• ..;n ::er~ea::;1:::·✓ J:-,t:l ·.v ell satura tea :· .. .it. -.:: nee saturated . . : :::ecomes ::cortv ;::er~eaole .:1nc ~e!a1ns ·.vater .r. ::-.e :::ore spaces cet·,;een :art:c;es Jna re1ec:.; J,.·: ':':<:cess. . :sen,aucr.s .::_n, . ..; ~J::\st.:::rms 1-.c1cate tr. .. H :~e t·1p1cal sou ;:one will .:1osoro a::out 2 .r.cnes :i ·.,·ater ::;eiore some ·.vater 1.; re1ec:ea :r :r.oves :o ::.e underlying oearocK. : ~uv SJturatea. :-:e sod ·.v1lt procaoly retain 3 .r.cnes o: ·.vJter per ::ct oi cepth. 7~e capacity of t:-.e sod tor.old iJrge •1oiu:r.es ,Jf water. together with 1nirequent :r.JJOr rainstorms .:1nd a hign evapotranspirauon rate. seriously reauces -Jrouna-water recnarge ana :::orm runo:i. Eva potra ns p1ra tion Most of the water trapped in the s011 zone returns to the atmosphere by evaporauon or tran- spiration by plants ( evapotranspirat1on I. On St. Thomas thu process 1s active throughout the year, and 90 ta-95 percent of the rainfall 1s returned to the atmosphere. The tendecy of the soil to gra nu- late 1s also conducive to evaporat1on. ,\s water 1s evaporated from the surface cf a saturated tight soil, the soil again becomes granular and exposes the soil at depth to the circulation of a 1r. Con- sequently, further rap1d evaporation of soil moisture results. Transpiration 1s a major means of water loss from the soil zone and also from the upper part of the aqu1fer, if the water table 1s near the land surface. Grasses and shallow-rooted plants can transpire water only from the upper few feet of the soil zone. but many kinds of trees, such as deep- rooted false tamarind. transpire water from depths of more than 2 0 feet. The effects of evapotranspiration may be seen 1n the channel of Bonne Resoluuon Gut below the gaging station. The gut flows 1n a predominantly bedrock channel a few feet wide for about l, 500 feet before reaching the alluv1ated embayment ilt Dorothea Bay. Base flow of the stream. ·.vhen less than 10,000 gpd !gallons per day), disappears 1n thu reach. The loss 1s attnbuted principally to transp1rat10n by the dense growth of brush and rur (J(JJ ; ( (a) avera e annual (b) Match 25-26 1963 k:) April 7-8 1963 ( (d) Ma 9-13 1963 (t) Au ust 28-29 1963 0 I I 4 SMILES ICALI ,oa ALL MAPS (f) Otct•btt 10-13 1965 Figure 7 .--l1ohyetal1 in Jnche1 of the long-term dtstlibuUon of rc110fc1II ( d l end of lndlVldual raln1torm a ( b-f) on St. Thomas. ( :rees oordenng tne stream. . ;:,~ ::-:e ~=oearance :: :r.e •1egetat1on in a dry i::enod. ::wr :::e •;eaeta- ::on 1n a stnp aoout 100 feet 'Ntde -n:t:i a :orai area :f about 3 acres benefas from t!"\e stream. '"'. :m:-nurn water less of 10. GOO q;::a. : . 6 :-:::Uion ;all:Jr.s ,Hrnuall-1. ·.-1,:,uid :r.::1c.:lte ~n o•,aootransoi- ;auon rate ::if 1 . .: ~::::er . .:a:L::-:s ::er .'l::re :er year, :r -1-1 .r.cnes. 3owden 1 1368 l c.:-mputed ::-:cr.tnl·r ;::otenual ~vaporauon ana soil-rr.01sture aei1c:ency at six stations on St. -=;01x using the metnoa cev1sea by : . ·.,;. 7hornthwa 1te. ?otent1al eva porauon ranged :rom 58 to 69 tnches and averaged 62 1ncnes per -,;ear. ;.ctual eva potranspirauon ( den ved from potential e•,apotransp1rat1on and change 1n soil :nouture I ranged from 41 to -16 1ncnes and averaged -13 inches per year. aowaen·s data shows a sod- :-io1sture deficiency ~ to 11 months of :he year at :he different stations. Surplus soil :-no1sture Jccurred only 1n the months of Septemoer to :--ovember. The authors oeheve that cond1t1ons Jre s1m1lar 1n St. 7homas. Streamflow The S to 10 percent of rainfall not returned to the atmosphere by evapotransp1rauon from the soil zone either recharges the ground-water reservoir or runs off to the sea. ;.nnual runoff in a ume of average rainfall ranges from about 2 to 8 percent of the nunfall. Most stream channels on St. Thomas are dry 11nd carry only storm runoff. Only two streams on :he island have perennial reaches. ln these reaches, about one-half to three-fourths of the flow 1s stonn runoff, and the remunder 1s base flow I ground- water outflc,,, to the streams l. F'rom O. 5 to 2 inches of water annually reaches the sea as storm runoff. The .1mount of storm run- off vanes from basin to basin, depenchng upon topography, soil motatura, exposure, and vegeta- tion. Base fie,,, of the su-eams with perenrual reaches. w1'11le oftan equal in volume to storm run- off, seldom reaches the sea. The flow usually infiltrates into ailuvial deposits 1n the lower reaches of the streams. Ground 'Nater From O. S 1ncn to as much as 5 inches oi the 10 ~:11niall .'lr.nuJ:iv .r.:ll:r:1tes ::-:es.: .• ,:-::: ;:-c...:s ::, reacn ,ne qrouna-water reser1-:i1r. .-. Her .:: ::-:e ·.;rouna-water reservc:r .:r dqu1:er :-::,.·es :,·, ;rav1ty :oward me sea. :. -:ere :ne wJ ,er :.'lole .s ,ntercepted t:y me lana Sl.r::ace .. ·:,Her .s c,s- ::-:argec as a spring .:::r JS :.:Jse ricw :.: ~ ::trea~. .'::-iere :t .s ::ear ,!'le lane sur:ace. ;;_c;: JS J1onq stream c:-:annels Jnd :n c::astai ,:~:::ia·1!'!':ents. ::1rge •1olumes of ·.vater are ,~ar.so:re-:i :::·, :IJnts ·.-:nose roots tap the qrour.a-wa:er reser,olr. :-.-.e ,ransp1rat1on by ~!ants a1rect!v :r::~ ::-.e ·Nater :a::ile ts so great t!'lat only ~1:-:ute c1..:.:!r,t1t:es :t ;rouna water ever reach tne sea . ..:,t:-:er as s:reJm- flow or as seepage d1rectl·, ::-.r::u-;n ::-.e so.I Jnc rocks. :-resh- Salt-V•ater .:-:terr.:ice :-resh water :n the aquifers ~tor.<.; :ne =.:-ust .s .n contact ·•·llth salt water ln ~ c·.nar:-.:-:: o'l:.te:-n. So long as water levels graae seawara. :resn water will discharge to the sea at t~.e snore. Dunng times of qround-water recharge. the :resh- -..vater lens th1ckens, d1splac1ng the underlying. heavier, salt water dc,,,nward and seaward. Dur- Lng tunes of no recharge, the fresh-water Lens thins, as ground water discharges to sea. Salt water, which moves into the normall•1 fresh ~-=ne :f water dunng umes of no recharge, 1s not entirely flushed out by fresh water when rech"rge occurs. Some remains behind. where it m1Xes w 1th inflwc1ng fresh water. The interface zone of brackish water 1s thick where fluctuauons 1n the size of the fresh-water lens are large. In some coastal areas, where the fresh-water lens 1s thin because of lack of ra1nfa.U or unfavor- aole topograph1c or geologic factors. the under- lying interface zone may extend inland several hundred feet at depths of but a few feet below the water table. The balance between salt water and fresn ·nater :n coastal aquifers 1s dehcilte and c.:in eas1l·1 ::.c disrupted by man's quest for water. Salt-w;iter encroachment can readily result by removing more water from the fresh-ater lens than u being replaced by recharge or by pumping a well at an excessive rate. 1n which case the fresh-water :iead 1s lowered. and movement oi salt water upward or honzontaUy into the fresh-water zone 1s induced. \U\ )·: 1 - ~- -- '.'ATER S:::C?CE3 . ~es:1 ·,:-:icer nas always :een .:: -::-::::::.:: st.::01'l ... St. 7::o~=S. :::.a1n :::cllec:ea :::: ~::-:is a."'.c 2:::rea .:1 <:::sterns .s stlll t:ie source ::i ··:a:er :::r 7.Cst ;~ra1 3!1C :...:r=an ~:~e:t1c s·.;cci~es. :ief:re ~ ~60 "'.:lls,ce ~a:n :::.a:c."'.~.e:-.cs 3:-.c J :ew :::.:; ·::eds ·:.-ere ::-:e ~.aJor source or ·::acer :::r ::uouc :;;..::::1,es. .3.nce ::-.en. :esaaea ·.vacer ::JS :eco~e ::-.e :-:-. .:1pr aource ct ·.vater for ouul1c .,·..:opues. Jnc ·:: Jter = a ri:;ea :rc:c. ?-Jerto ~ :cc . s a c ,ose sec ::::r,c. ,::::1arlotte Amalie nas a ::::ual ;:u:::llc ·.-:acer s·,:stem. ~resn water :s used for dnr."ani:; .:1r.a c;enera1 :1ouse- -.oid needs. and salt water :s usea tor san1tar_1 3na ::re-control purposes. 7::e rresn-wacer s·.:::ply. Jota1ned from salt-water a1sullat1on 01ants. :-:111- s:ae rain catchments. ~no a well, :s supplemented ::,y water barged from Puerto Rico. ?otaole water use and the sources oi the water :n figure a :,ot only show the 1ncreas1ng demand for water out also the s h1ft 1n sources of the water. In the late 1950's, with the excepuon of 1957. a drought year. catchments were the major source of water. Barged water became the major source of supplv 1n the early 1960's, but by the late 1960's, desalted water became the principal source of supply. Ne,uly all bu1ldinas, both pnvate and public. in Ch.Jrlott~ Amalle have roof catchments and cisterns. rn 1926, before the estabhshment of a public water system, abOut 200 pnvate and 17 public dug wells were 1n use in the urban area. Since then most of the wells have been acandoned jecause of sewage and salt-water contam1n.:iuor .. Some of the salty water was drawn into the wells irom tne sea as a result of overpump1ng, and some :Jf lt entered the wells from leaky salt-water pipes. -~ few of the wells are still pumped occasionally for nondnnking dome sue suppbes and for construe - t~on p~rposes. In recent years, wells have oeen r:!ug 1n eastern Chariotte Amalle for a supple~ental ··:ater supply for the two public-housing proiects. Several other wells have been dug 1n tne same ;eneral area for water for nondnnking domestic .. se. Since 1926, 18 pu.ohc hillside rain catchments have been constructed. .:;f these, 14 are con- :.ectea to the urban water-d1stnbut1on system. l 1 :: acer :s ~.a·..::e-:J :r:::rci ::-:e remaining :cur catc:-:- ~ents =·., .:-.c1·✓1cual Jsers or ::,y water :-.aulers. ".':-:e t::; :a 1 -" ~ea =: :ne ;:~ollc catcnments , s e st1- - 3 cea :: =e ~~ 3cres. 1na the scorai:;e :s est::nated :: -::.el~-: .•. .:.-. .;allcns. =iel1"tr.>le i:;ures are not ~•,allaole ::r. ::-:e ~mount cf ·Nater ·..:sea :rem any ci ::-:e c.=:c:-:.7.e::ts. -..:t :.:cal ·_,:eld :s esc1~.atea :o -::,e :J.~2J ;;:::c. :-. 3001t1::::n to tne ouoiic catcnments. :our :nvatei·, ::·::r.ea C.3tch:-:-.ents are t'."\ ::-:e :.2r:::an 3rea. ~ .;aHerv ·.veU at ::-:e a1rcort ·.·,as ar1 :~oortant .,,ource ::i ·.·,acer ::-. c:-.e l '.15•J 's. :r recorteol·, · . .-:e1dea 13, JJO gpa • .:n attemot to .:1crease ;:ro- ::uct1on resulted in salt-water encroacnr:'\ent. :1.J101ng tne well as a source of potable water. '.:i 1962 the ilrst desalting plant, ·.vtth a caoa- ::cy of 230,000 gpd, 'Nas put into proaucuon •... 1966 a olant of l :n1lhon gpd was put into proauc- ::on, and, °='I 1967. the start was made on a Z. 3 .-~llllon gpa desalung plant. The demand for water has increased six-fold since 1960 and sh01Ns little indication of levebng off. In 1962 and again in 1966, when desalting plants were put on hne, water demand increased almost overrught to absorb the increase in produc- tion. Water barging, considered a stopgap measure, has had to be continued to meet the demand. The desalting plants repartedly will produce water at an average cost of about Sl .oo per l, 000 ~a Uons when operating at max1mum efficiency. The cost of barqed water from Puerto Rico depends upon eqwpment used, but in 1967 averaged about 5 3. SO per 1 , 0 00 gallons. Water 1s sold to the .:onsumer at a cost of SO cents per ton, acout S2.0u ,::er l , 000 ai'I 11,...r,s. The difference between pro- jucuon cost and delivery cost is absorbed by the ·:1rg1n Islands Government. Rural St. Thomas :,ooftoo catchments and cisterns are still the -:-. a1or source of water for rural St. Thomas. Dur- .. -:g prolonged dry penods, rain water 1s supple- - ented by water hauled from pubhc-supp!y points . '.'1 Charlotte Amalle. Small ponds have oeen con- :tructed, tapping storm runoff for 1rngat10n water :::r tn.:ck g.irdening ar.d dnnk1ng water for stock. :i.nce 1962 several pnvate wells have been drilled TUT 1.J() .1.. ...: ..... '··-': : ser-:'!! ucns .::c :ca te :::at ·.v: nc ·:ewe::·,- :i :-.c ~::t :::-.::~·..:raucn 3re :-:a1or :3c:crs :r, ::-.e ~e::ver, :: ~:::::rail ::r:m :-es1aent1al struc~..:res •. -::qn ·.'✓::-.c ·:1!l clew ra1r. or£ a pitchea root cnentea ::aradel :c ::-:e ·.-.-:::a, ·.·,nereas a rain snaaow :r. :,:ccn:cr, :::: t:;e aeqree of roof pitch will occur en ::;e ,ee , .:::e :: J :-::,oi onented perpendicular to ::ie w1:1a. ·. -;;.-.a;:ea roof will be affected :n the same - ~:-.:-.er. ,.::-.: .... ~:-. probably :c J lesser c:e-;ree. "'.''-.e :~t ::::.::e::t :s ;:robably a ilat rcot w:i-. :i .:-..., ,.:; -~=-~:-.::: :-.e ':'C·:::e . .'.'ater cannot :low c:: :-.e r:c: .:, . s 5 ~J:n s:-.dacw :,ea tea. 5na t::e 1:c :onverts :-e r:c: ::-.co 3 terr.;:crary storage conta1r.er aunnq ·:.::::-::::e:;s::·: ~:i1ns. ~a1niall recoverv :in :lat ·:cis .s ::rooaoly ;reater than tr.at measured fr:r.-: ::-:e :-. 111s ,C'::: ca tcnr.1ents, . ..., :-ierea s recover-.: : n :: . ten ~:cis .s :,ooaoly 10 to 20 percent less, :::ecena1ng ... cr:e!"ltat:on and steepness oi ::::en. =-:;ure 2 5 shows an estimate oi the ar.nua1 c:sts :; :ollecting rainwater and of c1stern s:crJqe ::r :: small home. C,stem cost, amcrt:zea ever J 20- _.-ear period at 5 percent per ·1ear I interest costs -:::,t 1ncludedl, .s esomatea t,::; rJr.ge ire:-:-: ~S.00 ::er c :..01c foot for l O percent storage co ; 2 • 5 0 cer ::..01c :oot for l 00 percent storage oi t!ie total 3nnual recovered rainfall. ~dmfall recovery was ~ ~ 't =~~-~~ ~\~ \ :~r:~e:~--:~r/::;t:-~:-.;~ ;~: 3 ·-·e _ ::::·:er1 .::-.aer tr.ese ccnc:t:::::ns ·.v.::\..1c ·.-.e.:: -: :;:c. :: ·.vas assur.-:ea :!iat ·.vater . .::ss ::::.;e :.:: .:-.:;·~::.:;ent .o:.::ra:;e -,,cu1c :e ~ace :.;:; ::·, ·.·,a ter ::..r::-.a sec :r.::m ·.·,acer :-iaulers ac coses oi l J . .:,J. :r 30 ::o!lars ;:er l. :oo :;adons. 7'-:e fqure s:.O'Ns t:-iat. _5 ,ng ::-iese c:-:tena, :ne oot1mum ::::stern s,craqe w0u1a .::e aocut ~O ;:ercent ci expected annudl recoverv. :r aoout 3. 5 ~allons per square toot ot .::atchment. >1erage yield from ra1n:a1l aione wou1d ::.e acout ,2 .;;:c. ·-nnuai ·Nater ::::::st ·.vou1d range :r::::m ~130 ::::: ~136 dnnuaily, :r S7 .~5 c::er 1,_,00 :;allons :o ; 11 • .:.: oer l, ~00 :;Jllor.s. :,.--.nudl ::::st :: ! .· 1 :ercent c1stern storage would be S294 or Sl6.8u :er l. :oo ~allons. Cround ·.v ater Ground water 1s ava1lable in nearly all parts of the 1sland 1n sufficient c;uant1ty to oe oi :moor- :ance to the water supply. :n general. ·nelds oi wells are sufflc1ent only for 1ndiv1dua1 domest1c supphes. There are. :.owever. d few areas where yields to wells are large enough to warrant 500----------,-----,--------,---,---~~-,---, (/) a: C( ...I ...I 0 Q ~ - (/) 0 u ...I <I: =, z z C( 400 300 200 100 -------------------------------1 I I.,..Slorage 15 gallons per square, foot! I' ( 2 8 P:,,cent) . ' i----~----------+--·-·--- -· -· _____ ____,1 ___ ~ Suppltment water ! • 20 i,er 1000 gallons ,, I• Supplement woter IIOlper 1000 allons ~Stdr~glf 10 qallt11s I A~ s,uart foot Ii (~8 "rctn1) 0 l.,_...\,o,....... ______ 2:1,,o,.......----=3~0----:4~0:--~50~~60r-,7~0--;:.ao"'90~,:1'o:n-o- c1s r ERN STORAGE. IN PERCENT OF TOTAL CATCH Figure 2 S. --AMual cost of water from a roof catchment of 1. 000 square feet with a mal<!.'!lum yield of 48 gallons per day. 31 rur \ ~,::,e - .--.,c:11e . , .... es :.::r -::eter!1·un::-.:: ;,::ur.o-w~ter ::ctent:.a, '.r::m ;::-.ysicJi :,::cr.ci a,.a .o:~a~c1es :::ir se1ec:ec ·Neils _; ,1 ~;:,:.3 U I :.;poqracnv I ::Xcosure ' :,a1naqe area ?::tent1al I .. · 'aluei · ~na term ::-.cnes ,!ue I 3 lue I ·res ·:alue I Sum ot values i Id , ·_rie . ;;xi .:rest ot ! \ ~Iortn or soutn I ! I < -l:J i I I < 100 ' .; or less < S00 ,1aqe _ ;cpe I ' I • i I / I ' '~ I 1 Soucn s,ope i ! I i ·venera1 ~11- ➔) '. ! :-iortn ' I 101-200 I z 5-6 soo-1. ,Joo s,oce sloce ~ I I Central i She1tereo I I ·:alley ol l I I .;s-50 I I 2 I 2 1ntenor 2 201-300 ' 4 I 7-8 1. 000-S. 000 qeneral I I slope I valley I I I I l Large i I ! valley or I > so 1 1 301-400 6 9-10 5,000-10,000 I alluvial i ! flat ' I i i I > 400 a 11 or greater 10,000 + I Examples Well 3 l 2 z l 1 1.000-s.ooo Well 10 1 1 1 1 4 500 WeU 22 1 2 2 2 7 1. 000-5, 000 Well 20 1 3 2 8 12 10,000 Well 16 l 4 2 6 13 10,000 32 ruT ::-.e 'cevelop~ent :cf ;:u::ihc s:..opues :er :cca1 use. -:-·-:e ·.-nter. } s a ·.vnole, :s "'.lt ccor -:;'..:al1t·1, :e:ng 0:::;r:tl'.1 :-::::-.eral1zed, but CJ:. still ::ie ::r.s;cerea :.::ta:::ie. : ::.-. ::e ::ilencea ·:::t.-: ::stern ·:ncer, ·.·~elc:ng a -::-:ea ·.-:ater oi :'.1.Jre ac:ecta:::le pota- ::.::t·:. :-" :•.;se::clcers ·:1:,0 - . .i·:e ·.-:ells ;enerall·/ ~recer ~ ::·..:J1 s·:stc~ .• s:.:i; :-.,:: ::eil ·::acer :ar ·.-1,3sn1r.:; .. J·.vn ·.-:,ner:r.;, ~.:: 3Jmtar: c:..r::::cses ana ... ;::un::::- .'-.. He, c · tent;J i - .. ,., ·-·)11:,r:-•N'lter poter.c:,Jl _f Jr. :r:::J :::Jn ::. large part !:le deter~ined oy ,:-,e a·: 0 ,· • -r-u,H ~31nioll, tcoogr,1::::ny, ana •::!:<ocsur•.:: D s.::IJr r~::i.1- t1on. :., ·:;enera!, Jreas recc:•11ny t·.ss ,:-",n .,,1 .:-.c!ies oi rJiniall ha•;e a l:·.·1 :nunc- ·, ,cer:: :ten- ::al. :'he soutnern slcpcs ::: :~e tslana, .. :iere, 1ecause oi solar raa1at1on, -~'-'JPOtransp1rJt..)r, . s :,1gh and recnarge 1s l:·.v, ;enerally nave less Jround-water potent1<ll and ·neld r:iore r.1-,hly r.i1n- erallzed water than the nortn slooes. TJpograpn·1 1s important tn t"'-'" - '""" f!,1tter slopes ,Jrouna- water recharge 1s favored. A crude scale based on rainfall, topography, exposure. and drainage-basin .:irea was developed for est1mat1n•J yround-water potential of the rocks nf the island r table 41. The different features are assigned v, lucs ranging from u to d. The !lium of these vc!lu,:s is a number irom which an estimate of the ion~ -term vielJ of .:i well c,3n be obtained. ;,, deep well will ,.enerally ·,·1eld more water than a shallow well 1n the same location. ror the purpose of the scale. a well depth of Jbout 200 feet 1s assumed with the •.vater level 1n the well at 50 feet below land surface. Little water is yielded from depths ()f more than 2u0 feet below the water table. It 1s emphasized that even though conditions appear favorable foe obtaining .:i ..Jround-water supply, there 1s .Jlweys .:i P1J:iS1bdicy no water ·.vlll be obtained as .:i well mav not pcnccr.:ite water- !:leanng strat.::i. '.Vater 1n ,:.::,nsol1aJted Rocks The penneable z0ncs 0r tne c.Jnsohr!-t"rl r-"1cks consist of ooen 101nts ,1nd frJct1.:~es. :'~eJr r-.e 33 :and surface the 101nts are ocen--me result ::i ::eathenng ana release ot cressure. . ::1:-.t :cen- .. ,:;s, ::cwever .. -:arrow rao1a!y ·.v1th .::eptn, .:r.c ;enerall·; Jt cectr:s c: J :e•.v :,unarec :eet :::e•r }re :::o narrow to :ransmlt s::;r.ii1cant quantities oi ·::acer. ·,11 t~e bearock :::r~ations Jre ::::r:iKer. c·: :Ju1:s-- ::~ct'..lres 3lcn~ ·.-:~1:::~ ~-:·.-~-c"".t ~== :.::-:er,. :~Jee. : :-. some faults, edrth ~-.;·:e~ent .,as cr:.:sr.ca ::-e ~:::ck to .;ravel-size orecc:J. ·.vnereas .:-. :::-.ers ::-.e ~JCK :ias oeen reaucea :o J :lcuriiKe 3•-':..1stJr.ce :alled '.Jult ;ouqe. c:.recciaced fault: ::-.es :-.ot sealed b·1 :-n1neral de~os1ts or :Jule ;:::...;e cJr. ::e ·,ery perrr:eable and often extena to .;cccr:s :-.'Jnareds oi feet. ,~e .)flentauon oi :':'!any of t!'le ,,alleys ,r.a oays ,·11dentl1 1s controlled b•r a :ault ana Jo1r.t s·_:stem ,long wmch erosion has occurred. .'alleys, ::-:erefore. are oiten tnaicdtors oi zones Jf Jn extensive Jointing or iractunng system c:iac ~ay contain ground water. The yield to :,ells dnlled in the bedro~k 1s ,;mall--yeneraUy less than l. 000 gpd. ~.tany ·.veils w1U yield 5 to 10 gpm ( gallons per r.11nute, for about-10 hours. After that they y1eid at a :!lUCh reduced rate as a result of removal uf water iro:n storage in the immediate v1ciruty of the well. Once water in local storage 1s removed, the yield to the well is reduced to the general yield of the aquifer. For example, well 17 near w 1ntberg re- portedly yielded 12 gpm (17,000 gpd l for a 24- hour pumping period when first dnlled. However. almost daily use over the past S years has snown that the long-term yield of the well is about 2S0 ;allons per day. The consolidated rocks are permeable as a result of interconnected open fractures along joints and faults, which tend to be lineM. HO'N- ever, permeability may vary significantly alonq a llneauon. One example of possible linear pemeacd1tv ts the north-south fault in eastern Charlotte .:.malle. Permeability, as determined from pumping tests of wells, ranged from about 1 to 9 gpd per it2 r gallons per day per square foot l east ana west of the fault. Immediately along the fault zone 1n the ·11c1n1ty of the race track, however, permeacilay ranged from about 70 to l SO gpd per ft2. South- van:I along the fault permeab1hty was 1 .,pd per ft2 • · r t..i r ()(_;, J - The effective porosity, or storage capacity, of the consoUdated rock also 11 related to open inter- coMected fractures and JolnU. Effecuve porosity tn the upper Turpentine Run basin is estimated to be 4 percent based upcn changes 1n the ground- water level in response to rainfall. Effective porosity of the rocks in most of the island u esti- mated to be 1 percent or less. 'Nater in Unconsolidated Rock Water-bearing unconsolidated depcsits are present only 1n Turpenune Run Valley and in coastal embaymenu. These depcslts conalst of two dif- ferent l1thologlc types, which have a variety of water-bearing charactertst1cs. They can be divided into ( 1) a bouldery silt and clay alluv1wn, which contains lenses and beds of sand and gravel, and ( 2) beach deposits, predominantly coral sand and occasional 1nterbedded zones of coral, beech rock, and orgen1c silt and clay. In the coastal embay- ments, aUuVial and beach depo11t1 may 1nterf1nger. The alluvial deposits are predominantly fine grained, and, althou9h they have • h19h pcro1ity, they have a low permNbillty end wlll yield water only 1lowly to well•. Weter 1n theN depo1lt1 11 wttb f9w exception• under water-table cond.1t1on1. Sand end ;ravel beda end lenNa in the alluvium are rare. Wh .. pnNnt, h~, they wtU yield water rNdlly and act a• a lar;e collectcr ayltem into which water from the leH p-•ble alluvium wlll percolate. OccHlonelly the water in the send and gravel bed• 1• under erte1tan pre•_.. beceu1e they are confined by the lHa permeable overlying alluvium. 'nle beech depo11ta, prtncipelly medlua to coane canl sand, have • modsate to hllb per- mNbWty and poroaity end wUl yteJd water readily to welll. The moderate to hl9h permeability of the beech depo11t1 11 often detnmental in that Hlt- wetar encroachment can Nally occur. Graund water tn St. 'l'llalla• u uaumed to be under water-table condlUOfta--that ia, the weter surface 11 unconfined, open to the atmo1pbere, and free to rt•• and fall. Sufficient data ere not avail- able to 1how contoun of the surface of the water table throughout the i1lend. In ;enenl, the water table roughly parallel• the topography. The depth 34 co the water table 1s a few feet below land surface :n the coastal embayments but may be as much as 120 feet below land surface near the crest of the central ndge. The water table responds to changes 1n the quantity cf water stored 1n the ground-water reser- voirs. The water table nses when recharge from rainfall or streamflow exceeds the discharge; 1t declines when discharge to spnngs, streams, or the sea, evapotran1piration from the water table. and withdrawal of water from we Us exceed recharge. Water-table fluctuations The hydroqraph ofweU 1 1n figure 26 1s typical of the water-level fluctuations in the rock aquifer of the south coa1t. Recharge follows the infre- quent heavy ra1n1torm or smaller storms in a wet pertod. The overall low storage ca pee 1 ty of the rock causes a rapid rt1e in water levell, but the steep hydraulic graciienu re1ult in rapld lo11e1 and almolt a• rapid decline•. Figure 27 is the hydroqraph of well 24 tapp1n9 the alluvium and wHth-.d bedrock tn the lower TurpenUne Run Valley, and fiCJUte 28 11 the hydro- graph of well 21 in the alluvium of the upper beaiA. Recher;• 11 rec:et¥ed every time storm water run• off tn the 1treem am water level• riN. Betw"n time• of 1tcrm runoff, ;round-water lewl• ere pertly me1nta1md by the tnfiltrauon of be•• flow from the 1tree111 wben now 11 pre1ent. 'nle hydroqrapb of well 19 in figure 29 show1 the pett.-n of water-level fluciueuona of the rock aquifer tn upps 'l'w'penU• Run be•tn. The pattern 11 •1miler to that of the rock aquifer of the north coast and len,w valley• on the 1011th coelt. Here, greeter pennNbillty and 1tcn199 capacity end generally thicks 10&1 end alluvium reault ln • slower but more prolOCIIJed reaponae to recharge and a slower di1cher;e. The "troughs• in the hydrogreph durtnq Nrly 1965 went cau1ed by pump- age ( awraginq 18,000 ;pd l frcm a nearby well. Recher;• Th• bedrock aquifer 11 sinnc1pelly rechar;ed by 1nfUtrat1on of rain on the lend surface. Stream- flaw and storm runoff locally recher;e the alluvium, which may, in tum, contribute water to the bedrock aquifer tn the mejar valley• and allu- v1ated coe1tal embeymenta. \U\ (.)i.) ). . .:·~ .~ .. -:~- L l t :<.arnfall. ·1egetauon, evaporation, surflcia1 jeposas. and exposure to solar radiation are :ne ::-ia1n factors affecting recnarge to ::-:e aquifers. :.eaky-salt ·.vater and sewage mains 1n c:-:ar1otte ;,malle and effluent from sewage plants 1n tne T .. rpenune Run oasin also c:::-.tr:bute water to :::e aquifers as does effluent from septic tanKs ::irougn- ~ut ::-.!! ts land. Recharge from these sources ts .::etn::-:ental as 1t 1s a :::iotential source ot ::iolbtion. The oedroclc aquifer 1s recharged infrequently and oniy after a heavy rain or senes of lesser rains. 7he amount depends on the antecedent rainfall and the degree to which soil moisture has ::leen aep1eted by evapotransp1ra uon since the last rain. C:xtensive brush cover and the granular nature of the soil cause rapid evapotranspuauon. Conversely, the granular nature of the soil w1U aUov,, water to pass through the soil zone without :he soil being completely saturated--saturauon being required only along the conduits between the soil granules. This reduces the water needed to satisfy so1l-mo1sture requirements before recharge can take place. Even then. under dry conditions, a ma1or rainstorm of 2 inches or more, or the equi- valent in les1er rains, 1s necessary to i.n1tiate re- charge to the bedrock aqwfer. The amount of rainfall necessary for recharge vanes from one part of the island to another. On the north slope 1 inch of rain may cause recharge, whereas on the south slope. under dry condiUons, 3 inches or more may be necessary for recharge. The fluctuation of ground-water levels indicates that recharge to th• aquifers on the south-facing slope ■ is leaa frequent than on the narth-fac1ng slopes. Less tr.quent recharqe on the south slopes 1s attributed to the greacer solar rad1aUon received by these slope•. which resultl in increa1ed eve po- transpiration and a gr.eter soil-moisture deficiency. Consequently, a greater volume of water 1s neces- sary to overcome the soil-moisture def1c1ency before recharge takH pl•ce. Where the surticial deposiU ( saprolite or alluvium) are thick, ranvin; fr0m 2 to 15 feet, as on the north slope 1n die Y1Cinity of Dorothea, in upper Turpentine Run be•lJI, and in th• alluvial embey- ments, such as at Lon; Bey and the Harry S. Truman Airport, water u retained in the surf1c1al deposits and takes a much longer time to reach the bedrock aqwfer. Peak recharge to the bedrock aquifer may lag as much as a month behind the rainfall. ln some places little recharge reaches 37 :he oedrock aqu1fer--~s most 1s discharged to .spnngs er streams d1rectl•r from cne saproilte or 3 lluvium . = .s :,as oeen ocserved 1n me vie 1m ty of '.)orotnea on t:ie north slope. :<.unoif fr:,m ma1or ra 1nstorms 1s the pnnc1pal :-ecnarge to ::ie aquifers or the coastal emoayments -3na 1s an 1:-nportant source of recnarge to the -:1lluv1um cf T .. rpennne Run. 3ase flow of Turpen- :1ne Run and BoMe Resolution Gut at Dorothea 3ay, ·.,men present. also contnbutes recharge to :he unconsolidated aqu1ters 1n their respective oasins. For convenience of discussion. the island has oeen d1v1ded 1nto hve ground-water areas as shov,,n 1n figure 30. Esumates of yield 1n these areas are given 1n table 5. 7Jble ; . --C:n1matea y,el.d of ~rouncs-water ~reas. See t1q. Ju, ~:ouna-w"ter I area. :sumated v1e1a ~r.nual r~'1,uqe. \ \ I z i. 2 l ◄ 5 1re.t ~Q :,u lPG rnq1 yr I .~cnes I \ 3.6 450,000 \64 J.7 I t,onq ddv > .3 l/ 70. 000 11 25 L9 I L,ndberq Say l .2 1/ JO. 000 11 \I ◄. 3 3.4 150 .000 128 ~. z Upper aauii 2.3 300. 000 !; 110 2.8 Lower oas,n 1.1 ;o.ooo 1, 18 l. \ L6 zso.aoo 9l 1..: .q; 100.000 16 L3 10.0 100,000 16 . z !~tal 12 I. zso. 1)00 ◄5 S V ~pproxLmai. erwa of alluvium only. V Coe• not 1nc:lud• drunaqe t1ea1n1 at Ar••• I a ncl S .viucll coninllute recnar,i• to Area ~ from 1urtace- "' a ter runoff • .l/ Y:eld ,ncluded ,n ArN I total. 1/ Y1•ld 1nc:luded 1n Arwa 2 total. Ground-Water Area• Area 1 Area 1 encompass•• about haU the land area. It is underlain prtnc1pally by fractured volcanic tuff and breccia of the Louisenhot ronnation, on which 1 or 2 feec of soil have developed. On the south side of the island. from th• vicinity of Charlotte Amalie westward to Brewer■ Bay, the volcanic rock has been extensively fractured. The fractures, however. have been filled with 2:.\/.1 ./ f ( ( ~-----------,,---------------------.---------------- - .Al TL .Al N TIC OCEAN ~ ~ 111°20' EXPLANATION fCNI SYMaOL I A Surface-waler gaging slol1on •' OriUed well, numbtr rtftrtd to 1n Ital. 0 Dug well ..... Gallery 94 Spring, nwnbtr ref trtd lo in IHI. • Rain 9ag1 C Pollution from solt -water mains -, E ncroochmenl by sea water CARIBBEAN SEA -- Boundory ol oreo - ::-·· ··~ Alluvial deposils 2 Artas, see taplonohon btlow 0 2 , ....... L---''-----'----~- ___ J ~ •••oo· , ...... 04")0. L-------------'--------------------.&.-----------------·- ---- ---- ____ l_ - ,-- w co ( AREAS EXPLANATION Are...i 1 Wells rn rock 511 to 300 feet in depth will yield up to l , 000 gpd. In some larger basins and alluviated embayments yields up to 10,000 gpd may be possible. Water contains 1,000 to 1,500 my/l chloride. Wells drilled near the sea and below sea level may y 1eld brackish water when dnlled or If pumped at excessive rates. /1.rea 2 Wells in rock 50 to 250 feet in depth will yield up to 30,000 gpd. Generally, deeper wells have a higher yield. Short-term yields of selected wells may be as great as 150,000 gpd. Wells tapping alluvium of lower Turpentine Run will yield up to 10,000 gpd. Water contains about 1,000 mg/1 dissolved solids and about 200 mg/1 chloride. Little danger of salt-water encroachment except in lower Turpentine Run. -----------· - Area 3 'A'ells In ruck '.>U tu Lill) IL't:l 111 d,:1,Ll1 v;ill '/lt'l,l u1, to 5,000 ypd. 111 soInc ldr•Jl·r drt1111t1•Jt' t,.i!..iI11s, yields up tu llJ,llllU LJpd llldY lH-' P"!..i:;Jl,h!. W<1ter contains ab()ut 1,111111 IIHJ/l d1!..is1dvt~d :;(Jl1ds c1nd about 2110 111,J/I cldunde. 'v\',·ll.s dr1ll1·1I I1I•<1r tit,: sea <1nd bel,,w sed level 111.1y y1t·ld l,1,1,:L1,.l1 w.1L1·I when drtlkd 1)1 d pu111(H!d .ii 1·x, ,•:;:_;iv1· ,.11,·,;. Area 4 'A'ells In l1111e:;Lt,11e '..ill Lu I 'ill feel 111 d,:pl11 w 111 yield up to SO, lltlll lJpd. Sllurt-ter111 ylldd!..i cif selected wells mt.ly be <1s ,Jrt]ill .is l '..iI1, llllll 1J1,d. \Nater contains c1bout 1, 51111 111,J/I d1s:;,,lv1·d :,,,lid:, and 200 to Jllll llllJ/l c:hlt>rid1.·. Wells drlllt·d IH.'dl the sea or lie low se<.1 levt.::I 111dy yll.dd l1r,1t:I. 1:;l1 water when drilled or If µumped <1l l]xcessIve I<1k:.,. Area 5 Wells in rock Sil to )UU feet In de pl11 w 111 y JI] Id u 11 to 1,000 gpd. In general yields .ire :;111,dl. W.it<-1 contains l ,OOU to I, 500 nHJ/I d1:;!;;ulv1:d s"l1ds <111d 300 to 500 my/I chloride. Wells d11Jk·d uI1 pe,IIII- sulas and in codstal are<.1s •Jcner...illy will t~I1c1Ju11tl~1 brackish water. Cruund w<.1Lcr pnllull'd liy le<1ky salt-water mains 1n Charlotte /\111<1lie .ir,!.i. --------------------------------------- ---- figure 30.--Ground-water areas of St. Thomas show1n•J luc..i1w11 ol wt.:lls. spri11,Js. stream gages, and rain gayes. ·- -- secondary minerals. Alluvium and beach deposits fill the coastal embayments and are especially prominent 1n the Charlotte Amalle area. Ground-water Levels range from a few feet below land surface 1n the embayments near the sea to as :nuch as 120 feet below land surface on the central ndge. Depth to the water table IS greatest beneath ndges and least 1n the valleys and lowlands. Wells range 1n depth from 50 feet in the lO'N coastal areas to 250 feet or more near the central ndge. In general, the higher the altitude of the well site the greater the depth of the well. There 1s really no particular depth at which an aquifer can be successfully tapped, as yield depends enurely on the depth and density of open water-beanng frac- tures. A well in the Long Bay area (well 12) at an altitude of 40 feet was drilled to a depth of 120 feet before water-beanng fractures werw penetrated. Well 10, on the other hand, at an altitude of 320 feet on the slope of the central ridge. penetrated water-bearing fracGU"es at 60 feet. 'lbeae, of courH, are extremes. Long-term yields of well• generally range from 250 to 1,000 gpd, although initial or short-term yields may be 10 umes greater. 1\¥0 vaUey areas, Long Say and Lindberv Bay on the eaat and west edge of Charlotte Amalie, ra- spectively, have gre.ter ground-water potential than the remainder of Area 1 . Long Bay, --Th• Lon; Bay area liH in a basin about 1 square lllile 1n extent, of which about O. 3 square mile 11 alluvtatN coesuil embliyment, and the remainder 11 1teep-aloped volcanic rtdgea with little 1011 cover. Alluvium aa thick aa 60 t.et overlie ■ the bedrock. Near the c01at the alluvium underlie ■ and interfin9er■ with a thin beech-send deposit. A relatively tmpervtous clay overlie• the bedrock from a line uaut 1,500 feet lnland Ha- ward to the shoreline at loo; Bay, and probably extends out under Lani Bay. Water is present in the alluvtal deposita, but the main aquifer is the underlying volcanic roak. In gen .. !, the bedrock underlying !he alluvtwa yield• more water than that underl'(1ng the ridges. The zone of grNtest yteld 40 ,i ·Neds 1s :,Qu;;d -:J'( the rNo =~L;,tS :::~ss •. -:~ ·ne area. .. : :act-:r ,: __ -::~:::.:'.::-.: ·: ~:-.e ·;r:'Juc'..·. ··· -· ;;e?drcc~ 1;; ::ie ;•.<:?r.•::::1 _;L:uv11,;~ :hat 2:::.:. ~::: .i :::Hl.Lt'/ 1t ;enera1:·.1 ·.:.~:ds .• t:'.e ·.vJ:E:r ·- ··:e:,s ::iut 1t ·11elds ·.vJt'=r .;,:::.-:l'.1 to ::ie? .. -.:::e~ 1··::-.~ ::-:-:- rock aquifer. ~~e -:n:ic1paL -1re,1 :.t ~cc-. ---::e : · !h~ bedroc,c ~qu1!er crui.'l rne .3lll.;·:~·...:::. ~ :.-.,J (,:ot or the volcanic :-1'Jqes ,nHl :-v: : : .:-. , -: : ;P ::ie 1mperv1ous clay wieage cappin.; ::--~ .. ·.:•:~v: Jnd mostly upgrad1ent 1rom the area : -::2J./ water maLns. The long-term y:e1d cf tr.e aHu·✓1un·~ .'!arcc'-: aquifer 1s estimated tc be from 60. 00.: - ~ s, 1 ;r,o ,;:::d. The yield of wells ranges :r,m a:: ;'.Jt .: · J t:) i0,000 gpd. The high yield at scrr . .;::? ·;t :~'! -...,ells, however, has little to do wan ::- ~ I•_:-.; - :-arm yield of the aquifer. Susta1."1ec ;:,•;mpaq~ ::-. excess of the long-term yield of the a~u.te:- w,d deplete the fresh ground water 1n scora1e ar.d r~00- ably result in salt-water encroachment. Salt water has encroached in a MITOW' strip of the alluvial ~quifer bordering Long Bay because oi pumping dug wells 13, 14, and 15, which su;:;ply Pearson Gardena publlc housing. Nearly half the alluvtal aquifer, however, is contaminated to some degrae by lee Icy salt-water mains. The approximate llmiU of salt-water contamination are shown in figure 30. nte bedrock aquifer under- lying most of the contaminated alluvium contains fresh water because the pnncipal recharge area u upgradient of the relatively impermeable clay cap overlytng tha bedrock throughout most of the contaminated area•. Salt water has entered the bedrock in at least one place. Well 11 became salty after being pumped heavily for about l months. Salt water from the alluvium has apparently entered the bed- rock aquifer through several improperly construc- ted wells. In each the aMular space between the ·.·,all of the well and the casinq was left open, 3nd salt water moved down the aMular space, contam- inating the bedrock aquifer 1n the vic1ruty of the well. I 1...,1{ : ., : •r.' ':l:'.111::- ·: -.: .. :: ;::,erv1·:· . ., ·,; :as1n ar':- . :n1c:n 1s _:: ___ _ · .. -: :.; :r1;,. :~e : r.c o-=-, - : : - : :::: ~: ~ : -. - : . : lei~ . - : -: ~ - . ·.: . ,. • • 1 .. -· -·-·· .... -.: - _--~:- _. _ .. G~~~l .-l:".; ": .;:rcc,c l i .;J;.~_: --~ .:CClJ 1:-:. - 1,-::~ :: ~-- 3.Lt~~~f.! ~•_.,· -~J: ::-:~:-- ,'.trt.!$100S. ·: : "":r:-r:, ci 2:.:0 f~~t. 1.'-L'..--:· ·, =~J 6 1"3,/e : . ,-;- :-::::-, ">'Id. ➔scma~'!"'i :L' ").~ :.:.i ,,J 0pu. :1e~r:i:~ ··<: 1. 1. ~ ~-:?hi'lb1·, ·•1111. ·.::~Id i _,.:.;•_•Jo~ 1n the r-:t:,.-.:: !l ---,t • :'.~ er.:::aymcn:: !.or-,~ ,::t the cuq:ort. :.:~ ~,!..;,..-.'_:.: -~ ~eldt1•.1 c!·., :!iic·, :t°:':P! -]nd, tn•..:.:;, ." s ',.:,•1::.: :-Jntr:::-u:e :;.:,::.il-::~~n~le ~.lnt:t;.es :: ·.v1ter • ::> -~..: :.: ,·.:(!rl,,1nq o~:-:,,:,c .;_~•~:for. : • ,,-;:~r.t,;3! yield -:,f t!ie ::~~-=rock aqut!!'?r . _ .- ,·::: ",'.·••i , . .:: 04! JC, (hlJ :;pc, J.3SU!':'Un'j ::1.:ita -:: :J! ~e<l r~~. , -a r..,_.,~ aay .ir4a car. ce applled. 3alt-w11ter mains ln the 9oume field housing .;rga ar" known to leak, c1r.d 1t must be assumed :.:Jt ::-:.2 ,JUuvium in that vicinity 1s contaminat~. :-:-:e same care to prevent salt-water contamination ~Y tr:. ::roper well conatn1ct1on must be ta lcen n~re , s in the l:Jng Say area. .:.t 0ne ti:ne a ;•llerT paralleling the runway Jt :::e J1rcort wa• uaed for water supply. nus ~.JUery, which c:ollec:tad runoff from the ('IJnway ~r.a :aoreu w-Jter 1D tile elluvium and landfiH ! ;,r :1..t:.irl! •J~e. ::.1d • yield e1tunated to be 11, 000 .,pe1. U:-:ior.un,neiy. the gallery was overpumped "n:1 ;alt-water encroachment followed. Salt w-,ter 1s sull present m the alluviwn near the well ana :s .r. a Pos1t1on to intrude the bedrock aquifer. ·.vater from the gallery occas1onaUy u used for -H -- ::3ole purposes. :-:-:e use :i ·.vater irom · :: ::ra1nage for c:nni•ang purcoses, :t :ourse . . .j~=erous oecause ci t:ie presence of tox:c . ..: -::~·.nos sucn as nycrocaroons ana tetraetnvl :~:~ sollled a:rcr3it :c;els . - ~ - ~e~ 2 ,s the drainage ::iasin cf T'.;rpentine Run . . :-:··enience 1t :s separated :nto an upper ar.c ,, :..3sin; t:-:e upper ::ias1n above tne stream- -.-. J -:tation near l\1t. ::on, and the lower -:,as1n - . :-~e prtnc1cal rcc1es are volcanic flews. ,r-.'1 breccia. ..:.i!uvium as truck as -t0 '.eet . -" -_ ::-.e main stream c:iannel of the lower ::iasin, :r:t-::,ast-onented fractured and io1nted ;:-:,ne ··.:~r,:~:,ermaUy altered rock bisects the upper -:';.::~.;wells range from 40 to 250 feet :n .:::cth. -:-~e shallower wells tap tne alluvium .3na . -; ... :"':o:?r-:.: bedrock of lower Turpentine Run. ..,e ·!epth :f :he rock wells lS not necessanly a cn- :0r:::: :Jf ·;reater yield, but 1s usually an 1nd1c.:,- . Jn er -.vr:ere a zone of water-bearing fractures :;i:i ceno:?trated. Short-tenn yields from inch- ·::Ju..il rock wells 1n the upper basin are as qreat "d l: J. JOO gpd. Sustained yields, however, ·,:-v.;e from about 3,000 to 30,000 gpd. lndi- ·.: ,l: J ! .,,.ells 1n lower Turpent1ne Run yield as -:-. -::, 1 s 30,000 gpd, but sustained ground-water ::,:~ctcaw,>is of more than 10,000 gpd will probably r-:! "'.llt ,n :;ea-water encroachment. -.;,,;,•.Jr.d-water levels. --Contours of the ground- ·.-,acer surface during August 1965 and January 1 %6, ,.ire shown in figures 31 and 32. The a1TOWs 1n these maps indicate the general direction of ;round-w~ter movement. rn the upper basin. ·,,hen water levels are high, ground-water flow 1s spllt--part moving along the course of Turpentine quc:. .ind pa:-t moving through the fractured and 1ltered zone at Mt. Zion and emerging as a series .,f s~mngs discharging to Turpentine Run 1n the tawer basin. When ground-water levels are low ::1 tne 1.Joper basin, nearly all ground water 1s .rooably discharged through the fractured zone at '.~t. Zio:"I, and a temporary ground-water divide :s ~stabhshecl at the position shown in figure 31. Grour.c!-water levels in the basin fluctuate in relation to discharge from and recharge to the c;qu1fers. figures 29 and 27 are the hydrographs of wells 19 and 24 anUed in bedrock 1n the upper basin and in the alluvium and weathered rock of tU1 ~::/,4/::, REFERENCE NO. 15 .~. ·' l .: No data base is available for a detailed assessment of population within a particular radius of the site. The best available information foflows this note, and comists of a 1980 census by water district. Populations were estimated by adding together the populations of NCh district within the radius of interest. In cases where only a portion of a district is within the radius, population was prorated by area. \I.JI - ______ . _____ ........ __ l""'A ~, g FINAL REPORT-ANAL Kris Buras L L l l L l I I ~ ' ,_ - ~- I I I - WATER MANAGEMENT PLAN FOR THE ___ -_. -- --- ---.- PUBLIC WATER SYSTEM ·- ~~ ~··· . ' Prepared for . · · . · ·· 1 THE DEPARTMENf ·of _____ -- -------- -- ___ -_ ---- ---- -- --- -- - \ CONSERVATION AND CULTURAL AFFAIRS GOVERNMENT OF THE VIRGIN ISLANDS Prepared by - CH2M . CH2M Hill SOUTHEAST, INC. IIHILL Project No. GN14325.AO ____ __... July, 1983, I L! I U U J :,t:~: .q. ,:;., - - ... -- -- ,. --- -- - • • _. _. ... ... ( I ( ( Table ]-] DEMOGRAPHIC DATA FOR THE U.S. VIRGIN ISLANDS ''li!!H I!!! ff~d lllau l- r,~~••~~ Pala ..,.,.11- u.iii ••ca liiela ... 1.,..a ..,_,ad• u.a tine I ■ iloaela L ■t•r•t Piijiil[an.-Uii,, Fu,~• · '°'--..---.,.1.--....-... , .. 1 ~llcl iliFL '"UP') ~ ~ ica"!ll i,■Jii") ,.,_,., ,._1.11 ";r> it•lu) sear> iee--1- ~!.!l "•· .JJ;:&··!_ lll I!! ...... I 1,•n ... ~" .. .. 1,24' SID 42' " 100 1.,~ ii-. U'J ... n• l .. , 1 .. 1,on ,. 100 10 l,UO .. n• 10 ) >ti u, - IS Ml ,,. ))0 u ,. 00 >II n • IM 11 II - u, u u HJ )0 I) .. s ~ .. " 1Ul'M• 1K ,. - II r;m r.m m m 1B r.ns 1,01( HI ~ll IU ..._ I IH IU .,. J , .. n ... ltS ll ... 00 u , . , IH I '" I JIS • ~ u ' 1,sn u * '9 1,1'2 ,. J .. ,. ,. l,Ml H J.0 "' JO I 2,u, • u • 1,110 H H • , .... n 12 " • ..... ..... >,ft: ,1, • •.1• 1,1:11 l,UJ ,u us s,••· J -~" ),tl4 .. u IH J l,M II ... as ..• , H ,,.. SlO ,s l,SSI " n, ))J " I a,,n SI : .. J,HJ .. "' J,t3' •1' 1,11, 10 • 1,10s .... , ... n t,m ,n , ... u ,,n, ... , .... JS .. ... •• '~- lll .. ·•:c Ht ISi .., us l,IH S50 Ha 111 IH II ... a a ,., l II J,US ... ... 21' Je 2,1ft w ,,. u, JO >,JU 11' 1,, .. ~, JO u S,JSI ISi .... , '" ... , . .... , ... no l,IM. no , ... , JH IIO .. '" JI * "' ' 21 SM IH JI ,.. H ,.n• '90 ,a HJ ,., .. u SJ JU • '·"' "' ll 2',J 211 .. ,., . ,.aes ,,us ... ... J,tH J •• • us 19' us 1.,21 J,UI ,,us U4 ... " ..... ,,on , ... s HJ HS • ••• ,:as, ,:111 u, ... ···" ,,ns ,,sa 29' !IS II 11 u • H " 100 n ,. d H dU ,.,HI n;d£ UJ ... uo IIJ JS ~AUi 11:111 R";Tii Hi H,iii >,df m ~ ",lti it;iii r;lll r.m •••• I »s 121 n .. ,. U> - n , .. H SH 441 JJ) IMI n J , ... , .,. a,uts ., H 11,HJ ... J,OH ., n s.•• l ,1140 l,OtS an H , 11,no Ut J,111 llO .. 11,IH '" J,au 110 •• iJ,atl HJ J,IU 110 ,. ' '" IH .. - IM •• .,. u, •• s HJ as ,. • ,n )l ' ... JI t •• D - It ' " H .... 101 • 1)4 ~ l '·"" ..... l,9lt '·'" 1,2'2 a,nt '·"' l,4U J,UO I J,M '·'" , .. H • ,.n• .... , , ... , " • s.au a,,as ,,n, u JO t 1.u1 .... , , ... •• ..... ••• J J,llt •• . .... , 11,HI ,., .. ,. •• , ... - ... u H a.,n .. ... II H ,.au , .. ... 12 JS ll , ... , .. H .. n , .... ... 61 - ., ,,,12 .,. " 100 ,. II , ... ..... . .... ., •• J,- , .... . .... •J ... .,.,, ... ,.. l,)H JI> IM II l,SH .,, , ..• ,. - .. . .... 612 .. 100 .. ,.. sss .. .., II .. • •• JU , .. 161 JS SIJ •• Jtt 112 JS ,,. )U JH Ill J) .. ,.. lit .. .. H .. lH .. ... H OU au '° JIJ H n ,., - u. IS ... ,.. ISi IS ... u, ·~· H II .. .. n II u u II JJJ , .. II .. , II - ..Yll ..i..m ...lalll _JI! JI ..lJll ..l&lll ..1al1I _!!! -1! __!,,M 1,010 J,IH -.!!! .!! au ..... .., .. ~··- •. ,u "' 12,u., u., .. H,IJJ '·"' ... 111,JWI u,, .. U,loH J,1)1 ... IL!!! llaBl Ba Lill Lill W..tJ! liJ!l l!d!! hlll !di! ,s.,uo ~ ,a,"" ~! 1,000 - - -- ... -,_ Llal1 ... • _,Ii larce1 ICII • •dlael1 Ila • 1-1 ■1 MINIM, '-·- ::._r. -· rr• -,•~•L•a•~-~u••-•s•,•7~ ••s • • • - - - •• ( - - - - - - ., - UUIPUf UAIA ,\_ Y(AA 1980 I 0 I SIA IC f • 01 DISIAICI • 0~ IHSIAICf • OJ Ol~UIICf • 04 DISIAICf • OS Ul~fAICf • 116 DISUIICI • OJ DUINICI • o• DISUIICI • 119 DIHAICI • u, DISIHICI • II DISIAICf • 12 DUUIICI • I J OISUIICI • 14 UISIAICI • 15 l>ISfAICI • 16 DISfftlCf • I 1 DISUIICI • •• DUfAICf • ... fOIAL I St.ANU I I ,- ,~ - •---- INffANAL UEMANO ----• POfAltLE NOH-POI KGAL..10 llGAL.10 •-------------- IN1£ANAl. WAJEA SUPPLY-------------• •---- POIABLE WAIEA -~1•-• •-- NOH-POIABL.£ WAIEA--• (Ir.JEAN OIHl:A 10 AL SAt. f OftEA fOIAL KGAL,O llGAL.10 •Ga~,o llC.AL,o KGAL'D KGAL,O •--- EaltMNAL l>tMANO ---• POIARLE NUN-J>Uf -.<.At.i'D KC.AL.1'0 --------------------------------------------------·-------------------------------------------------------- •• e o.o 6 •• le4 o.o 1.4 o.o o.o o.o 5.4 o.o 5.4 .... , o.o I ... J 4 • I o.o .., o.o o.o o.o 15.6 0.11 15.6 21.9 ••• 21.9 s.o o.o s.q o.o o.o o.o 22.9 o.o 22.¥ es.e o.o es.e 22.1 o.o ,u.) 0.1) o.o o.o 6.).1 (I·" C.J.1 IJ1.0 ••• I Je.9 l4 • 1 o.o >•· o.o •• o •• o 102 • .J o.o I 02'o J se •• r ..... ., •• s eJ.e JO.o I I l•i o.o o.o o.o .,s., .u.e 501.5 10•-· ·•·· 110.1 20.J 65.o es. o.o 56e0 56o0 ,, .. so.o I 2 .J. 4 e.t.a •••• e2.5 11.2 e.11 19-~ o.o o.o o.o 6 .J • .) o.o 6J.J 540.8 ••• 1t40.e 102.e 16.0 11e. o.o o.o 0. I) 4.l2o41! o.o 42'.t.ii 91.o I I• I 1oa.1 llol 11.0 IJ.' o.o ,s.o 15.0 8J.9 o." 11:,. 9 50.J o.o so.J .... o.o .... o.o o.o o.o •c..9 c,.o 46.9 . , ... •••• ••••• 28.6 ao.o . .)8. e: o.u l!loO 1s.u IJ9.1 u.oJ I :,9 • 1 2-.,. r o~. I >•a.e •••• a ro.o 210.0 . -,.o 62.0 ,.1.0 195.tl 4. 2 200.11 •o.r C,. 0 •o. r .. , o.o 9.r o.o o.o 0. C, .)I .o o.o J1.o 2, ••• ., •• .J •••I• 1 JJ •• o.o .J.Jo8 o.c> •l oO o.o 18 I .t> 26 • .J 201.9 ,., .. s, .• 16¥.6 ..,., ••• ,,o., o.o c,.o o.o 591 • .J 51 .c. 646.9 561 .2 .ro.r SM1.9 .,~.5 211.0 11e.5 o.o u.o o.u 448. 1 20., 4bV.4 o •• o.o o •• 0 • I o.o 0 • I o.o o.o o.o u.!> o.o 0.5 2s.1 o.o 2s.r .J. 6 o.o .Jo6 o.o o.o l. J l2 • I o.o 22.1 l;t 7. I' 4oe1.e 6.2J.9 J:,2.0 9~5.9 o.o 15.2.0 .29d6.0 IVU.6 .JI lc..c, S,1vice D1t111<:l1 •• N11mhr1rtl :.-a-~·•~----•·OJJ'l'I~ ·- 0 ,.13i biio ....... . FIGURE 3-e. 1~1 Projected demand of the service districts on St. Thomas for the year 1980. L REFERENCE NO. 16 . i ; i , V I NUS CORPORATION TELECON NOTE I CONTIIOL NO: DAT£: TIME: UL· 'tno, - ?-1 OISTIIIIUTION: BETWEEN: OF: PHONE: lJ s G--c; f~ ...-i:..... ( ~C'°I h l("f ·'·d '-t' ( AND: INUSI DtaCUISION: ~ x · Qvl? • o \ ~ wL:,i WScY:::: n1:cr ~ Crmc::,,c4;.,,~ :ii \ ._ y,rye. ..,;J. ~ cl f= N:'?:!r k o,, o , ~, 1: , 9 :+:tpQ e · ::::tde;t ~ m a\ a ~ , t t!N ,l,'f:,+,.-._3 :::;;;tt,,. eae, 41:IPd :i:½- Cel"3' ,( V,:C. 41 1:f! Ste+~ "-- -+b:-:- ,, fr.. ~ !&. 1'5),1,.. " ~ :r;. .. 1=6J -➔{; A, t x- d ~ ro:<cy>;: ::#:1:: ,1 6er:: Nf14A~ :;t, · & 4MI ,k::-+ 2-: ~ &M-- ~ ~ fx olrwJ~ c1::: ~ ~. REFERENCE NO. 17 ''' : '· I : , .. _,., -·''--'""f I NUS CORPORATION CONTROL NO: DIITllllUTION: IITWIIN: ~c v, Goe +i - <.,..,<./ I C,. r ~lier DISCUaaM)flt: ro r 6cc:+:z. est ·rn a..tr--2 TEL.ECON NO TE 1 TIMI: 1430 OP: "40NI: l=>o I ca.,·,~ ( gc'i) 77'S-t11,,o INUSI 52) Q - 40 0 oc ,iJo..::(; 46d (( 5 Po $:f 'J{,cm 9c I 30 'fno,,, J:fcoccts ace kep± At± ~,b\., WGCkS: {m,, Laure/ Grl~~) ~, Gae:ta: :::W,;.,nh<s "/ H 6: wells ~ ,'rotabl, < m~:s td d m ,o ►0AAC ~ :Jte. ~ HYdl ¼c -• c r-·, Af1:i01C:, ;,,.,c;,lt t&......_~ '2,Q 0 , ta os:e Aos;:::::£mss ~.. I"' l [~ c::ri+l,, at Stnoce W9--1i c t.u<lt, REFERENCE NO. 18 '.:.:.,:·, i • . .'' I NUS CORPORATION TELE CON NOT£] CONTIIOLNO: nMI: '-/40 0IITIUIUTION: IITWIIN: o,: ,ttONI: LerJf'\ a r &. 1-?e ~cL 7)PNR (v::c) (8"09 ) 7 7 't J 3?.IJ AND: 7) \,a,~ - I ,.~ !NUii t, fe ♦ ob (( ,le wo '2 ctsila Yoc)o.,,t Hnuen H0-, ln-C\:c 0,2,, ~a.u& o,,, WM&, Lf - \Ne ( / lcco:f,ns , v..Jt!,// lq5s. cfepi, -to SjcPYoo+c:ia.Ji•., '?'~ \ 1-- $C c-Y:1<9 'P ,, ,.x t Is _as, __ , (.){.) ..:.. .--, ·:'"1.:; ·.- ..::. -. .:, ~-.! / REFERENCE NO. 19 VUS CCRPORA TION OAT!. ANO -- ~ \IL kc-- lELE(CN ,icn 510 I PHONI I I.~ 9 \ 71 5-) -~ f Li / ' . .i u .L .,,:: . __ :; :.-.·, ,;., I I -.us. I REFERENCE NO. 20 . \ SULJECT RECORD OF COMMUNICATION su••A•Y o, C0IU1IUNICATION ~ REC'D (lllKOftl of"·"' clleckall lbo9w) '"01111: TIMI ~ ~00 IPA,_ ..... ""'" ·••1.1oc•• ••• Ne~-........ WNtC ......... UHD UNTIi. •u~1.•. S&NAWT&JI. I_ TU\ REFERENCE NO. 21 ! r _i,:; ·i CDI .. ~Weral Programs Cor~11tion March 6, 1989 Hs. caroline Kwan U.S. Environmental Protection Agency 26 Federal Plaza New York, New York 10278 Project: Document No: Subject: Dear Hs. Kwan: EPA Contract No. 68-01-7331 T648-C02-EP-CZUU-1 CLP Sample Analysis Data Summary case No. 3900 I Ser 25 Tutu Vellfield Area Vork Assignment 648 Enclosed please find the summary CLP analyses results for samples taken in the Tutu Vellfield Area, St. Thomas, U.S. Virgin Islands on September 12 and 15, 1988. The samples were analyzed by Cenref Labs Brighton, Colorado. The identification and location of the three samples are given below: Sample i eT-62 eE-63 eE-64 Sample Location Tutu Texaco Service Station - oil/water separator Tutu Esso Service Station - holding tank Tutu Esso Service Station - oil/water separator Ve have taken the liberty to limit the list of compounds to include benzenes, substituted benzenes, dichloroethane, dichloroethene, trichloroethane, trichloroethene, tetrachloroethane, tetrachloroethene compounds, toluene, xylene and any other compounds found above detection limits. These compounds (BTEX and chlorinated hydrocarbons) were identified as groundwater contaminants in past EPA sampling events conducted in the Tutu Vellfield Area. Alkanes and related compounds were not included. It can be seen from the results that toluene, ethylbenzene and xylene were found in all three samples. A number of benzene-containing volatile and extractable compounds were tentatively identified in all three samples. Sample eE-64 from the Esso oil/water separator also contained detectable levels of methylene chloride, 2-butanone, 1,1,1 - trichloroethane, tetrachloroethene and benzene. Copies of the laboratory analysis data sheets for the three samples are attached. 40 Ream Sa., 10th Floor New York. NY l<XXl6 ZU 393-9634 r·u,· ,· .. · ·1 ... ~, i,) ~-- . .::'. -~· .f.) --~' Hs. C. Kwan Page Two ...bM Federal Programs C.Orporation All three of these sampling locations will be resampled later this month due to a break in the chain-of-custody during the original sample shipment. Should you have any questions regarding these data, please do not hesitate to call me at (212) 393-9634. Sincerely, Manager SG/rw Attachment cc: P. Fischetti J. Claypoole NYC File Document Control (VP8/47)NY-GHO i i.J \ LAB ANALYSIS DATA SHEETS CENREF LABS SAS No. 3900!, Set 25 VOIATILE OBGANIC c:."CJ'IPCXJND (mg/kg) Caap,und: eT-62 eE-63 eT-64 •thylene chloride 2Su 250u 57 \./ 1,1-dichloroethene 25u 250u 25u 1,1-dichlorethane 25u 250u 2Su 1,2-dichloroethene (total) 2Su 250u 2Su 1,2-dichloroethane 25u 250u 25u 2-butanone SOu SOOu 62 ✓ 1,1,1-trichloroethane 25u 250u 100 ✓ trichloroethene 25u 250u 25u 1,1,2-trichloroethane 25u 250u 25u/ tetrachloroethene 25u 250u 65 1,1,2,2-tetrachloroethane 25u 250u 2Su / benzene 25u 250u 29 toluene 140 1800 2900• ethylbenzene 400 230 4500• xylene (total) 160 1600 1900• Tentativel1 identified canpounds: propyl benzene 1200J 890J ethyl methyl benzene 860J 6000J 1600J C3 substituted benzene 2200J C3 substituted benzene 1800J trimethyl benzene 370J 8000J lOOOJ ethyl methyl benzene 1700J 940J trimethyl benzene 1300J 1900J trimethyl benzene 390J lOOOJ methyl propyl benzene 470J 1400J lOOOJ methyl methyl ethyl benzene 550J llOOJ C4 substituted benzene 280J 2000J 760J C4 substituted benzene 1200J C4 substituted benezene 950J ethyl dimethyl benzene 440J tetramethyl benzene 680J ethyl methyl benzene 940J tetramethyl benzene 400J u - below the detection limit J - estimated value • - value from analysis of a diluted aliquot of this sample PM/52 iU1 EXTRACTABLE ORGANIC ca-tPOONDS (mg/kg) Tentativelr identified canpounds: eT-62 eE-63 eT-64 C4 substituted benzene 220J 930J 1400J C4 substituted benzene 620J ethyl dimethyl benzene 690J 780J 1-methyl-3-(1-methyl ethyl)-benzene 720J 1600J tetramethyl benzene 540J 360J tetramethyl benzene 710J 410J methyl-propyl benzene 720J dihydro-methyl benzene 260J dimethyl-(methyl ethyl)-benzene 260J methyl naphthalene 990J substituted methyl naphthalene 390J 290J dimethyl naphthalene 250J dihydro-methyl-indene 690J 490J dihydro-dimethyl-indene 270J J - estimated concentration r1.1 r uu 1 '.•· .. ..::~ ._:,c:- ,.. 019 lHA EPA SAMPLE NO. HIGH CONCENTRATION VOLATILE ANALYSIS DATA SHEET Lt:1:b Na~e: Co,l'I\JU) ~ Lab Code: 0 ?dlb '1J 1J Case No.: Contract: ~-01. '14b5 s,q.s 3q oo:r.; SAS No.: Sd::ris SDG No.: nA::Ae9, Phase Type: W'IL Lab sample IO: Phase weight: I.() (g) Lab File IO: ::z8133? Final Extract Volume: 10.0 (mL) Date Received: 9{::u./~~ Aliquot Volume: IOQ (UL) Date Separated: Conversion Factor: So Date Analyzed: ;tJ/111£!' ~ I CONCENTRATION CAS NO. COMPOUND (mg/Kg) I 74-87-3---------Chloromethane _______ l 500 74-83-9---------Bromomet..~ane-e--______ l .:fOO 75-01-4---------Vinyl Chloride ______ I 500 75-00-3---------Chloroethane~--,.~-----' 500 75-09-2---------Methylene Chloride _____ ! .:J6C) 67-64-1---------Acetone _______________ l 500• 75-15-o---------carbon Disulfide ______ ! •SO i 75-JS-4---------1,l-Dichloroethene _____ l ~So I 75-34-3--------1,1-oichloroethane.....,. ___ ~_I ~S'"o / 540-59-o--------l,2-Dichloroethene (total) I 4 ~ 0o I 67-66-3---------Chloroform -, ~ I 107-06-2--------1,2-oichloroethane _____ l ___ :>. __ ~_a __ _ I 78-93-3---------2-Butanone~----,------' 5"00 I 71-55-6---------1, 1, 1-Trichloroethane ____ l .2so I 56-23-5---------carbon Tetrachloride ____ ! ~.s~ I 108-05-4-------Vinyl Acetate ________ ! .$)? I 75-27-4---------Bromodichloromethane ____ l *S32 I 78-87-5---------1,2-Dichloropropane _____ l <SP I 10061-01-5----cis-l,3-0ichloropropene ___ l gsr;? I 79-01-6-------Trichloroethene~ _______ l -4P I 124-48-1------Dibromochloromethane ____ l ,;)So I 79-00-5------1,l,2-Trichloroethan~ ____ I .zso I 71-43-2------Benzene _____________ l ~o I 10061-02-6-----trans-l,J-Dicbloropropene_l ,;)SO I 75-25-2------Bromoform __________ l -,<SO I 1os-10-1-------4-Methyl-2-Pentanone ____ l soo I 591-78-6-------2-Hexanone _________ l 500 Q I t{ I U I U I v( I U,. I tl. I IL I Ur I -t--1 1A I l& I tJ. I p I u I t,< I /,l. I "'- I U I "" I (,I. I ~ I t4 I IA. I I{, I ~ I IA-I u_ I I 127-18-4------Tetrachloroethene ______ l .'S~ I 79-34-5--------1,l,2,2-Tetrachloroethane I r?;s:~ I 108-88-3--------Toluene ___________ l /800 I 108-90-7--------Chlorobenzene _______ l a:s~ ,~-4@11_ I 100-41-4--------Ethylbenzene ________ l .:J:Jo I 100-42-s--------styrene __ _,.,,..,..---------' ~So I 1330-20-7-------Xylene (total) _______ ! /600 - '-----------------------'------ f \)~ ~¥ FORM I HCV ,\\\'t"t; ~ \\'> '\~·-..• I IA- I I __ I L t.A- I '--' I I uuJ :,,.:.:,h::-::: J./00 - 020 lHE EPA SAMPLE NO. HIGH CONCENTRATION VOLATILE ANALYSIS DATA SHEET TENTATIVELY IDENTIFIED COMPOUNDS . I ~';/; cfaU Contract: b!'.cJ1,2vlfl RA:Ao 0l1 /j~ sA.s.JFe,o_r n L~b Name: Lab Code: -~---+1- case No.: ___ SAS No.: SA:t-:c SDG No.: nAAD9'7 Phase Type: u .. :i:J:L Lab Sample ID: Phase weight: L.- 0 (g) Lab File IO: >8/.3:?~ Final Extract Volume: 10.0 (mL) Date Received: '1 L.;,.~i, I Aliquot Volume: 6Jo (UL) Date Separated: Conversion Factor: .so Date Analyzed: /?J /;9 /!J' . 1 Number TICs found: /0 I I I EST. CONC. I CAS NUMBER I COMPOUND NAME I RT I (mg/Kg) I Q I I ====== ====-.m j -== --=== I ========- j ====~---==- j rm I I 1. L036SI ,_- ..... ,evl Ekazf',,e I /.S.~~ I /"'2oo I J 1 I 2. ______ , («J&naa2a c/·li,yl(l'l~tf,rt &@1'.l'lf: I /.,j~:s(? I &,(JOO I :Z: I I J -______ I waPlnva e.., S°f'4a:rorc:fi Bcaunr. I /S:-6 9 I d:).;,oo I ::r: I I 4 ·------' «a4awo C.s Su,osi"-1"6,' 6,,,z,at. I /~.t:JR I /<i:"0 I X I 5.========='~~~,, .,.:,._.~"'-'~ 8Pn~aS- I /'2.~I' I ef'ttJtJtJ ;r I r ~:-----:;f;· ffijJ~flE:: ;* : ::Et~ f : : 1;:=--==--==--==--==--==-!hffff~l:iif: ! :1:.; : };; 1-: : I 11. ______ I ! ________ I I 12. t ________ I I 13. I ________ I I 14. I ________ I I 15. ! ________ I I 16. ! ________ I I 11. I ________ I 18. '------ --' 19. '--------' 20. '--------' 21. '--------' 22. '--------' 23. '------ --' 24. '------'--' 25. '------'--' 26. '------'--' 27. '------'--' 28. '------'--' 29. '------'--' JO. l ______ l __ f ------- ------------- ----'------'--' ' FORM I HCV-TIC .. . (\ . 0~~ IUT ~-- \\) ' - ' -'-- 220 lHB EPA SAMPLE NO. HIGn CONCENTRATION EXTRACTABLE ANALYSIS DATA SHEET Lab Name: C.. ~ (b ( L~.bs Contract: & g-01- 7</ t,5 Lab Code: CEAJ/l..(F Case No.: SAS No. :3~CIJI-StZS SDG No.: lJAAv~7 Phase Type: Lab Sample ID: Phase weight: WlL I . / (g) Lab File ID: '>C/JtJO Final Extract Volume: J. 0 (mL) (UL) Date Received: 1-21-ffi Injec~ion Volume: Date Separated: - Conversion Factor: 20 Date Extracted: lo-1..-g1 pH: 1.J) Date Analyzed: /t,-/1· '1~ c.;.s No. COMPOtmD l CONCE!ITRATICN (mg/Kg) Q 108-95-2--------?hencl ___________ l _________ _ lll-44-4--------bis(2-C~lc=oethyl)et~er ___ l _________ _ 95-57-8---------2-Chlorophenol _______ l _________ _ 541-73-1--------1,3-Dichloro~enzene _____ l _________ _ 106-46-7--------1,4-Dichlorobenzene _____ l _________ _ 100-51-6--------:enzyl alcohol _______ ! _________ _ 95-50-l---------l,2-Dichlorobenzene _____ l _________ _ 95-48-7---------2-Methylphenol _______ l _______ __ _ 108-60-l--------bis(2-Chloroisopropyl)ether I 106-44-5--------4-Methylphenol -,------- --- 621-64-7--------N-Nitroso-di-n-prcpylamine_l 1 67-72-1---------Hexachloroethane ______ l _________ _ I 98-95-3---------Nitrobenzene ________ l _________ _ I 78-59-1---------Isophorone _________ l _________ _ I 88-75-5---------2-Nitrophenol ________ l _________ _ I 105-67-9--------2,4-Dimethylphenol _____ l _________ _ I 65-85-0---------Eenzoic acid ________ l _________ _ I 111-91-l--------bis(2-Chloroethoxy)metllane I ______ _ I 120-83-2-------2,4-Dichlorophenol · -i --- 1 120-s2-1--------1,2,4-Trichlorobenzene ___ l _________ _ I 91-20-3---------Naphthalene~ ________ I _________ _ I 106-47-8--------4-Chloroaniline..,._ ______ I_,.. ________ _ I 87-68-3---------Hexacnlorobutadiene _____ l _________ _ I 59-50-7---------4-Chloro-3-methylphenol ___ l _________ _ I 91-57-6---------2-Methylnaphthalene ______ l _________ _ I 77-47-4---------Hexachlorocyclopentadiene I I 88-06-2---------2,4,6-Trichlorophenol -,------- --- I 95-95-4---------2,4,5-Trichlorophenol ____ l _________ _ I 91-58-7--------2-Chloronaphthalene _____ l _________ _ I 88-74-4---~-----2-Nitroaniline _______ l _________ _ I 131-11-3--------Dimethylphthalate ______ l _______ __ _ I 208-96-8--------Acenaphthylene _______ l _______ __ _ I 606-20-2--------2,6-Din~trotoluene _____ l 1- _______________________ I ______ _ ------~'~ f '-<::;; FORM I HCE-l. IUT OOJ /.::/o •I ,,: .. _ ._-_.. l 221 lHC EPA SAMPLE NO. HIGH CONCENTRATION EXTRAcrABLE ANALYSIS DATA SHEET Lab· Na1=e: ft-~" flt. f L ~ b~ Contract: &8 -t> /- 7</ t, 5 -gAA.oc,7 La,-, Code: C t11)i£ F case No. : SAS No. : 3f~dr-<; ,-zs SDG No. : BAAe,'1'7 Phase Type: W I l-- Lab Sample IO: Phase weight: I , I (g) Lab File IO: >CI /~0 Final Extract Volume: I. O {mL) Date Received: 1-2..1-1g Injection Volume: I (UL} Date Separated: Conversion Factor: LO Date Extracted: /t)-"-'6g pH: 1-D Date Analyzed: 10-11-gg CONCE!-1TRA TI OH CAS NO. CO!-!POUND (t1g/Kg) Q I I I I 99-09-2---------3-Nit=oaniline _______ l __________ I I 83-32-9---------Acenapht~ene ________ l I I s1-2s-s---------2,~- □init=ophenol ______ l I I 100-02-7--------4-Nit=ophenol ________ l I I 132-64-9--------Dibenzofur3n ________ l I I 121-14-2--------2,4-Dinit=otoluene _____ l I I 84-66-2---------Diethylphthalate ______ l I I 7005-72-3-------4-Chlorophenyl-phenylet.~er I I I 86-73-7---------Fluorene _________ :_:, I I 100-01-6--------4-Nitroaniline _______ l I I 534-52-1--------4,6-Dinitro-2-methylphenol I I I 86-30-6---------N-Nitrosodiphenylamine (1)-1 I I 101-55-3--------4-Bromophenyl-phenylether--=I I I 319-84-6--------alpha-BHC. __________ I .:100 t..<.... I I 118-74-1--------Hexachlorobenzene ______ l I I 319-05-7--------beta-BHC. ____________ I .JC-Q u.. I I 87-86-5---------Pentachlorophenol ______ l I I 58-89-9---------ga:cma-BHC (Lindane) _____ I ::i.c-o t..(... I I as-01-a---------Phenanthrene ________ l-. I I 120-12-1--------Anthracene _________ l I I 31.9-86-8--------delta-BHC. __________ I ,2CD LL I I 76-44-8---------Heptachlor _________ l .__..) .... o_o ___ , '-'- I I 309-00-2--------Aldrin ____________ l __ ,2..,.Q~D:....... __ I u.. I I 84-74-2---------Di-n-butylphthalate _____ l _______ l ___ l I 206-44-0--------Fluoranthene _ _,. ______ J _______ I ___ I I 1024-57-3-------Heptachlor epoxide _____ l_-=..:i.~·~o~o:;_ __ I u..- I I 27323-18-B------Monochlorobiphenyl _____ l_......:..1~0_0~0;;...... __ I L~ I I 2051-60-7-------Dichlorobiphenyl.,_ _____ l_---:..l~D~o~o~ __ I l~ I I 2051-61-8-------Trichlorobiphenyl ______ l_---:.l~D~o~O ___ I I.,(_ I I 2 0 51-62-9---=----Tetrachlorobipheny l _____ I _..__,;l....,.D~v~o~ __ I LL I / 129-oo-o--------Pyrene. ___________ l _______ l ___ l I 5103-74-2-------gamma-Chlordane. _______ l __ ~~~o~D ___ ~ LA. I '---------=------""'!'"""~-~-:--:--~--,--1-------'---' {l) - cannot be separated from Diphenylamine 'O'{_, ~~ TUT ~'\)v FORM I HCE-2 1 -=·· 222 lHD EPA SAMPLE NO. HIGH CONCENTRATION EXTRACTABLE ANALYSIS DATA SHEET Lab Name: (ti, 0, l I,. b 5 contract: /.J'i-t;(-71./~5 BA A Oct 7 Lab Code: (etl)flf:.F Case No.: 5: SAS No. :3ft'{)r-5,,-2.7 SDG No.: ~AAo17 Phase Type: WI L. Lab Sample ID: Phase weight: I . I (g) Lab File ID: >c I I~ 0 Final Extract Volume: i - 0 (mL) Date Received: '[-21-ii Injection Volume: I (UL) Date Separated: - Conversion Factor: z Date Extracted: ld-~·r.t pH: 7-.i) Date Analyzed: /~: - If - t.S CONCE~iTR.l\TIOU c.~ r.o. CQMPOt:.nm (mg/Kg) Q I I I I 959-98-8--------E~dosulfan I ________ l ___ )~C_O __ I Lt I 5103-71-9-------alpha-Chlordane _______ l .:ioo I '-l I 25429-29-2------Pentachlorobiphenyl _____ l /OOD I ~~ I 72-55-9---------4, 4 '-DOE __________ , .')Ct] I IA I 60-57-1---------Dieldrin_~ ________ I .:JO'D I u. I 26601-64-9------Hexachlorobiphenyl _____ l I ooo I ~ I I 72-20-a---------Endrin_,,_ __________ I .:ico l~'-l.. 1 1 ~ /,j I 33213-65-9------Endosulfan II ________ l __ ......._2~O_0___ l;..«- 1 72-54-8---------4,4 '-DDD __ ..,_.. _______ I :ioc Ll 1 I 28655-71-2------Heptachlorobiphenyl _____ l IQQD I u.. I I 85-68-7---------Butylbenzylphthalate ____ l I ___ I I 1031-07-8-------Endosulfan sulfate _____ ! ~vc I L~ I I 50-29-3---------4, 4 '-DDT __________ I ?,OD I LA I I 53494-70-5------Endrin ketone ________ ! _;; DC I L,(. I I 56-55-3---------Benzo(a)anthracene _____ l · I ___ I I 72-43-5---------Methoxychlor ________ l ..:>oo I ~ I I 21.8-01-9--------Chrysene_-:--:-~--...-----' I ___ I I 55722-26-4------octachloro.biphenyl..,,...,.. ____ I ..:Jo D c I lA I J 91-94-1---------J,3 1 -Dichlorobenzidine~--' I __ _ I l.l.7-Bl.-7--------bis(2-Ethylhexyl)pgthalate_l I __ I 53742-07-7------Nonachlorobiphenyl _____ l ::iovo I Ll. I 2051.-24-3-------Decachlorobiphenyl _____ l .;;c,oo I LI... I 117-84-o--------oi-n-octylphthalate _____ l I __ _ I 205-99-2--------Benzo(b)fluoranthene ____ l I __ _ I 207-08-9--------Benzo(k)fluoranthene ____ l I __ _ I 50-32-8---------Benzo(a)pyrene-:-,-______ I I __ _ I 193-39-5--------Indeno(l,2,3-cd)pyrene ___ l I __ _ I 53-70-3---------Dibenz(a,h)anthracene ____ l I __ _ I 191-24-2--------Benzo(g,h,i)perylene ____ l I __ _ I - I I __ f FORM I HCE-3 ~ 4A~ (D~ 'I!/ \: '\ I - 1 -, - - - 223 lB:F EPA SAHPt,,E NO. HI:GH CONCENT!tAffON EXTRACTABI.E ANALYSl:S CATA SHEET TDTATIVELY IDENTXnED COMPOUNDS I tab Name: __ c_~ __ a ....... R .... e .... {_L __ (J. __ 4. __ b __ s ____ _ I cont..-act:: &!-{,'l-7'-l~S I ------- Lab Code: C.c11Ji£F case No.: SAS No.: .JtP,r-,S".;.-.1:5 SOG No.: BAAd97 Phase Type: W/L Lal:::l -Sample ID: Phase weight: /,. I (g) Lal:::l File ID: > ~llt)O Finai Extra~ Volume: (:mL) Date Received: I Injection Volume: conversion Factor: pH: ';, D (uL) Date Separated: ----- 10 D t EX": d /L) - d, -g 'i· a e -=ac~e : ____ ,;;_ Date Analyzed: /CJ -//-gg Number T:cs found: Iv ' -· I I QS NUMBER COMPOUND NAME RT 1-=====-=----- 1 1. ______ c., S·d:"~·-•·"-' ?,-,oz~a,e Y.1.(£ I 2. ______ C.-, c-u,_.-T __ .....,,~ :l<,<nz~r,~ C/.,~t:" J. ______ E:'th._l ,,i_O':f1/... .. I ~co?"CC:: 9.,r 4. 5;$7'7.3 1-mt'~i;l-,<-li-2:, ... 1.,.,+,L/l-~c--unl"I q ':;Q -, 5. ______ I ±e:tr"-"" 1 1, ,_;..~- 1 ],,, 7 ..:c, Hf=-r·,,-,.,,, I IL2-.S1 I 6. I ~e+r,-.,rn,; "4.-' •~?.,.-:t,Z.:'."' IV,;:": C/1) H '" I 16. /" ( I 7 • I ,--1 ob, ..-irr ...... 1 .., #, .. I ;;,.,,,,._, µ F - /" I/ H Q f /,. -2t, I a. I «,.,·,,.,,., 'C A11'a.n.- µF:Ck)/J;)lr I 12.Ng I 9. f ,....." ... h'' ~i1 :9h~h-1..-,.-& µr::=r-,,~,r I '~i.2 I 10. I UrH .~ •. -,.. t.11t_..., r., ,....+= r c.,q -➔•Jr, I .23, ,2'.,; I 11. 1,.:.1.,c:--: I Eicc<,.,,.,e I ;;y .~{; I 12 • I lH)(f', ''--'"' ', 1 . t •· ,.,., rht,f'\ I ;15, ~5" I 13. I 'k:"tcc•·.... ~11-_l:..-I\L_ I .:is. 81 I 14. I «., ... "r'"·'•;j" ~l!'.-,,y l...2/p,..2~- I 15. I '~"'tcr,q, All'S::".Yx I .J1- '-lr.c I 16. ! ,.t.,,,..t;:0,,,,.0 Al ,,,,.0 , I .,2s_ ~7 I 17 • I • 1 » rr1a.;r: c., (W>4, I ·39 • <J ( I 18. I i+:ntO·"'cXl i:.tvP±-& I -~I- IP~ I 19. ! ______________ ! ___ _ I 20. '--------------'---- ' 21. '--------------'---- 1 22. '--------------'---- 1 23. '--------------'---- 1 24. 1 _____________ 1 ___ _ I 2s. ! ______________ ! ___ _ I 26. '-------------'---- ! 27. , ______________ ! ___ _ I 2a. ! ______________ ! ___ _ 1 29. '--------------'---- 30. , ______________ ! ___ _ _,.. _______ , ______________ , ___ _ f FORM I HCE-TIC != I ' t I I I I I I I I I I I I I I I I I I I I I I I I I I I I I EST. CONC. I (me , ·-:g) I Q -= I '1-~0 I J i/,.,;a I ;;;c /,, f,i:2 I ' I 7'1 .. I :r: ~~) I X ·7 / /') I 7T (,e_ '{() I "I. & 1(2_ I ;:r: 9<if.' I --r l~~Q I ...,~c I :r. 7/,.(2_ I ;;r- 7fpQ I T IS(Y"'; I ;;:r: ~,,3C-/") I :r , / I':() I -,- lie.QC: I T 13to I -I I I I I I I I I I I I I I ()01. ._ ..... · .. ~.? ·-:~; .,, I I I I I I I I I I I I I I I I I I I I I I -, I I I I I I I I I I I ., LA , .. -- 048 l.HA EPA SAMPLE NO. HIGH CONCENTRATION VOIATIU: ANALYSIS DATA SHEET L~ b NaI:Je: _.;::c~Q...._.O .... c .... e ..... ,~---=La...;A'-,1\?...._.c:.. .... , ---- Lab Code: C;, ore f- case No.: Phase Type: Phase weight: ,.o (g) final Extract Volwne: IO.Q (mL) P..liq,..:.ot: Volu:ne: IQ (uL) Conversion Factor: S. D C:O.S NO. Contract: (p<it ·O\-J4(p~ I I I 3AAa9)< 3'100L SAS No. : ~t 2.S SDG No. : ""E>AB093- Lab Sample ID: Lab File ID: 28\\::,2. Date Received: 9 b. 2 l crsY:. Date Separated: Date Analyzed: 1D I 5 l1>'a CONCEHTRATION (mg/Kg) Q I I 74-67-3---------C:!.:::::.-c:et!:ane ________ l e,ol lA.- 74-83-9---------==::::::.c=e~hane ________ l :50 I 11 75-01-4---------~l.:.:::tl C!llo::-i.de_, _____ I SD 1_1 .... 1 __ 75-00-3---------C!:lc:.-cetha~e ________ j SO I u., 75-09-2---------?-!e"C..~y.!.ene Chloride _____ ! 53:: I __ _ 67-64-1---------Ace-:cne ___________ l :$0 I Lt, 75-15-0---------car::on Disulfide ______ ! 6 5 I L>:: 75-35-4---------1, 1-Dicb.loroethene _____ l Z;:> I L':: 75-3 4-3---------1, 1-Dichloroethane _____ l ,2, 51 l,b:: 540-59-0--------l,2-Dichloroethene (total} I ~:;, I V::: 67-66-3---------Chlorofon:i _________ l 2,S I y.... I 107-06-2--------l,2-Dichloroethane _____ l ~;:,~I /l 78-93-3---------2-::utanone _________ l CR?- I I ~ 71-55-6---------1, 1, 1-Trichloroet!'lane ____ l 10 o ___ I 56-23-5---------ca::on Tetrachloride ____ ! ¢$ I IA I J.08-05-4--------Vinyl Acetate ________ ! 2-5 I LA I 75-27-4---------Broi:::iodichloromethane. ____ l 25 I IA I 78-87-5---------1,2-Dichloropropane _____ l ,;5 I (ht I 10061-01-5------cis-l, 3-Dichloropropene. ___ l ,.e, I , I>- I 79-01-6---------Trichloroethene _______ l 2.5 I tJ. I 124-48-1--------Dibromochloromethane ____ l k!:2 I 14 t 79-oo-s---------1,1,2-Trichloroethai:e ____ l ,.Zf;, IL::':-: I 71-43-2---------Benzene ___________ l is , ___ I l.0061.-02-6------trans-l, 3-Dichloropropene I .2.5 I 1 & I 75-2S-2---------Bro1:2ofoni ________ ===I A? I t,, I ios-10-1--------4-Methyl-2-Pentanone ____ l So I u_ l 591.-78-6--------2-Hexanone _________ l So I L>:-- I 1.27-18-4--------Tetrachloroethene ______ l tpS I ___ I .. 79-34-5---------1,l,2,2-Tetrachloroethane I ~~ fE' /1~ 108-88-3--------Toluene ~ ~·~~ : £ I l ~ 108-90-7--------:hlorobenzene ________ ~~ v ~I l.00-41-4--------~thylbenzene ________ -~•==~-- IL._! 100-42-5--------Styrene ___________ l I ~Q_ I...,.,,,.__! l 1330-20-7-------Xylene (total) ______ l-t';# f'fM =ii 1,C I '------------------------'------'--' ~ Va('J...{!_ {., 0..,,.../\ Cb-Ad'-ft;,'f c;.t- (/(1-tJl12_J} q{,94.c-{_ £:-/- i l.\. FORM I HCV -½'l, -i ..-· ,., .: t.'.i,/\,v- ~ -•~ - . " \ u \ - , l ,, - ·J _:,, (... .. , 049 lHE EPA SAMPLE NO. HIGH CONCENTRATION VOLATILE ANAL1SIS DATA SHEET TENTATIVELY IDENTIFIED COMPOUNDS I L cib N .:ime: C R O re \: LA\:,'::;, C:lntract: lpK :0 \-1;':! lo? : ::::E::>b ~ Q9 i r 3~oo~ Lab Code: CR ore t Case No.: --- SAS No.: :?d 2.':) SOG No.: bf\A09,-=t- Phase Type: WI.L Phase weight: ,.o (g) Final Extract Vol~e: \Q. 0 (mL) Aliquot VolUJ:1e: \ D (UL) Conversion Fac~or: S .0 Nu.n.ber T=cs found: 10 Lab Lab Date Date Date Sample ID: File ID: '7 A \\32.. Received: ~li'§ Separated: Analyzed: 10 ls \ii I EST. CONC. I I c..;s Nu"}!3E?. I CC~O'LilD NA.M~ l RT I (mg/Kg) I Q I I ============ 1 =====--==--=========--=== I ====== I =====-===-- I ---- I ! 1. 1Q?J4>'::>\ • -~cp,il 1¼t,1el\.2 I 2.1-\"+- I -cgqc I ;S 1 I 2. ____ 1e;~;~•t~:'.i;;LI\Jl I 21.'-ly, I l(p0O I$ ! I J • ______ I-\-____ ~_,, _ __!_;?_! A..J- I 11.-55 I 1000 I ~ I I 4 . ______ l ~ ' I 7:2.1:;, I 9 L./Q I ,:S I s · ______ I ..--......~~~~=-"-~~~....,....--_I 2.2. .$1 I 19 00 l ::S I --1 6. ______ I..J...1..~~.u...i.~ ........ ~~~-....---1 '2~.S't l 1000 I ;:;i I I 7 · ______ I ..ll4.l:~..J.¥..-+-'~~~~~U,,,,M.~....,__ I 2 '1 · o Le I 10 o O I :s I I a . ______ I ..=,:i.,J,,.l.l~~~~ ........ ~~~~~"""- I ~ '±· 2.~ I t Io o I :S I I 9. ______ l~.....;;i.~..;;::..J~J,.l.l.~~..-..:~...::.:~-1 .ZS.le, I 1::4>0 I .:5 I I 10. ______ l,.e.l.cAf""\ 0 m"lBcor1f\.J. I .2<,,20 I ~io I :S I I 11. _____ I ., l ____ l ______ l __ l I 12 . _____ ! ____________ ! __________ I __ I I 13 . ______ ! _____________ ! ___________ ! __ ! I 14 . ______ ! _____________ ! ___________ I __ I I 15. _____ I ____________ I __ ......:..... _______ I __ I I 16. _____ I ____________ I __________ ! __ ! I 17 • _____ I ____________ I __________ I __ I I 1a • _____ I ____________ I _________ I __ I I 19 • _____ ! ____________ ! _________ I __ I I 20. _____ I ____________ I _________ I __ I I 21. _____ I ____________ I _________ I __ I I 22 • _____ ! ____________ ! _________ I __ I I 23 • _____ I ________ _.__ ___ I _________ I __ I I 24 • _____ ! ____________ ! _________ I __ I I 25 • _____ I ____________ I _________ I __ I I 26. _____ I ____________ I _________ I __ I I 27 • _____ I ____________ I _________ I __ I I 2a • _____ ! ____________ ! __________ ! __ ! I 29 • _____ I ____________ I _________ I __ I I 30. _____ I ____________ I _________ l __ l I ______ ! ___________ ! ___________ I __ I .. ' FORM Ir.CV-TIC - • 'j"i 1 i__, I -;· .. 265 lHB EPA SAMPLE NO. HIGH CONCENTRATION EXTRACTABLE ANALYSIS DATA SHEET Con tract: I., 8 ·Of· 7c./ t, 5 Lab Code: CE t\JllJ f Case No.: SAS No. : 3fCtJr•5_t2S SDG No. : BAAD'i 7 - - Phase Type: uJIL Lab Sample ID: Phase weight: 1.0 (g) Lab File ID: ').C//0/ rinal Extract Volume: J. D (mL) Date Received: __f,;:_ZJ -f; <g Injection Volume: (uL) Date Separated: Conversion Factor: 20 Date Extracted: l~-t.-g,g pH: "1. D Date Analyzed: /t,-/1· ~f! CONCE!-ITRATION CAS NO. COMPOUND (mg/Kg) Q I I 108-95-2--------?hencl __________________ l I lll-44-4--------bis(2-Chlc=oetilyl)et~er ,--- 1 95-57-8---------2-Chlorophenol I I 541-73-1--------1,3-Dichlorobenzene ,--- 1 106-46-7--------1,4-Dichloroben:ene I --- 1 100-51-6--------Benzyl alcohol I --- 1 95-50-1---------1,2-Dichlorobenzene I --- 1 95-48-7---------2-Methylphenol I --- 1 108-60-l--------bis(2-Chloroisopropyl)ether I I 106-44-5--------4-Methylphenol - ,--- 1 621-64-7--------N-Nitroso-di-n-propylamine I I 67-72-1---------Hexachloroethane _____ := ,--- 1 98-95-3---------Nitrobenzene I I 78-59-1---------Isophorone 1--- 1 88-75-5---------2-Nitrophenol I I 105-67-9-------2,4-Dimethylphenol ,--- 1 65-85-o-------Benzoic acid I I 111-91-l-------bis(2-Chloroethoxy)methane ,--- 1 120-83-2-------2,4-Dichlorophenol · -i I I 120-s2-1--------l,2,4-Trichlorobenzene ___ l 1:::::1 I 91-20-3---------Naphthalene......,. ________ I t ___ l 106-47-8--------4-Chloroaniline-______ l I ___ I 87-68-3--------Hexachlorobutagiene _____ l- I ___ I 59-50-7---------4-Chloro-3-methylphenol ___ l t ___ l 91-57-6--------2-Methylnaphthalene___,....,...,_ ___ I I ___ I 77-47-4---------Hexachlorocyclopentadiene I t ___ l aa-06-2---------2,4,6-Trichlorophenol __ :::1 I ___ I 95-95-4---------2,4,5-Trichlorophenol ____ l I ___ I 91-58-7---------2-Chloronaphthalene _____ l I ___ I 88-74-4---~-----2-Nitroaniline _______ l I ___ I 131-11-3--------Dimethylphthalate ______ l t ___ l 208-96-8--------Acenaphthylene......,. ______ I • I ___ I 606-20-2--------2,6-Din~trotoluene _____ l l~I ___________________ f ___ , -<~.':? ., FORM I HCE-1 ! U i UUl 1/86 ,, -:· . . ~ .:. - •· r._ - -- -· .. 266 lHC EPA SAMPLE NO. HIGH CONCENTRATION EXTRACTABLE ANALYSIS DATA SHEET Lab· Name: Cw fl.t f L~ b~ Contract: &8-0J-7</(,5 La""' Code: CtnJe,&F Case No.: SAS No.: 3f()4f->dZS SDG No.: BAAc,c,7 Phase Type: WIL-- Lab Sample ID: Phase weight: , . 0 (g) Lab File ID: '>Cl/{)/ .. Final Extract Volume: I, Q (mL) Date Received: q_-21-~</ Injection Volume: I (UL) Date Separated: - Conversion Factor: 1-D Date Extracted: Io-~ -g g pH: 1-0 Date Analyzed: Iv -11- gg CAS NO. COMPOUND CONCENTRATION (mg/Kg) Q I I I I I 99-O9-2---------3-Nit=caniline I I I I 83-32-9---------Acenapht.~ene I I I I s1-2s-s---------2.~-Dinit=ophenol I I I I 1OO-O2-1--------4-Nitrophenol I I I I 132-64-9--------Dibenzofuran I I I I 121-14-2--------2,4-Dinitrotoluene I I I I 84-66-2---------Diethylphthalate I I I I 7OO5-72-3-------4-Chlorophenyl-phenylether_t I I l 86-73-7---------Fluorene I I I I 1OO-O1-6--------4-Nitroaniline I I I I 534-52-1--------4,6-Dinitro-2-methylphenol I I I I 86-3O-6---------N-Nitrosodiphenylamine (l)=I I I I 1O1-55-3--------4-Bromophenyl-phenylether __ l I I I 319-84-6--------alpha-BHC I .:JOO I t.L I I 118-74-1--------Hexachlorobenzene I I I I 319-85-7--------beta-BHC I ,2.CO I u.. I I 87-86-5---------Pentachlorophenol I I I I 58-89-9--------gamma-BHC (Lindane) I ·aoa I l.'- I I 85-01-8---------Phenanthrene ~- I I I 12O-12-7--------Anthracene I I I I 319-86-8-------delta-BHC I :1QD I t.L I I 76-44-8--------Heptachlor I ,2.QQ I t.L.. I I 3O9-OO-2--------Aldrin I . :J.QD I (.,L I I 84-74-2---------oi-n-butylphthalate I I I I 2O6-44-O--------Fluoranthene I I I I 1O24-57-3------Heptachlor epoxide I ..:J.D o I '-4- I I 27J2J-18-8------Monochlorobiphenyl I IDOO I u.. I I 2O51-6O-7-------Oichlorobiphenyl I ID O() I LL I I 2O51-61-8-------Trichlorobiphenyl I lDDO I L,(_ I I 2O51-62-9---=----Tetrachlorobiphenyl I IOVQ I ~ I I 129-OO-O--------Pyrene I I I I 51O3-74-2-------gamma-Chlordane I ..:.100 ~ u. I I I I 12e:> ._. (1) - cannot .be separated from Diphenylamine ~~'-' HCr:-2' 'O,AJ FORM I ; t.)·-1 ()( J) .· :,·_::, / / .-:·- . ·-- -- - . lHD 267 EPA SAMPLE NO. HIGH CONCENTRATION EXTRACTABLE ANALYSIS DATA SHEET La.b Name: Ctn o,£ I,. b 5 Contract: ~'a-C/-7l/ t,5 "BA A D q g Lab Code: (EttJ/ll;F Case No.: SAS No. :3ftcr-s.rzf SOG No.: 13.AA0'17 Phase Type: WlL. Lab Sample ID: Phase weight: I .D (g) Lab File ID: >c I lo 1 Final Extract Volume: l- D (mL) Date Received: q--z,-g~ - Injection Volume: I (UL) Date Separated: - Conversion Factor: ~o Date Ext::-ac~ed: Itri,· 'o. '5 pH: 1 0 Date Analyzed: l~ -11-gg CONCENTRATION c:..s NO. COMPOUND (-mg/Kg) Q I I I 959-98-8--------Endosulfan I -------- .:JCO I ll 1 5103-71-9-------alpha-Chlordane ______ _ I 25429-29-2------Pentachlorobiphenyl ____ _ :J.D D I I..(,_ I ODQ I 1-4. I 72-55-9---------4,4'-DDE _________ _ I 60-57-1---------Dieldrin ---,.----,---.....;.. __ I 26601-64-9------Hexachlorobiphenyl ____ _ .200 I L4. .:JOO I u I ODO I L(_ I l 72-20-a---------Endrin ----------- l 33213-65-9------Endosulfan II -------- 1 72-54-8---------4,4'-DDD .:JCQ '~'(<._ (,. :J.QD I I /;}j;r_ :) DD u I ' 28655-71-2------Heptachlorobiphenyl ____ _ IQQ') I 85-68-7---------Butylbenzylphthalate ___ _ I 1031-07-8-------Endosulfan sulfate _____ ! .::ioo I 50-29-3---------4,4'-DDT __________ I -~DO ...:ioD I 53494-70-5------Endrin ketcne ________ t __ -=-=~-- 1 56-55-3---------Benzo(a)anthracene _____ l_-_____ _ ..:> OD t 72-43-5---------Methoxychlcr ________ l __ --=:a.-=-.;:_-- I 218-01-9--------Chrysene _ __, ________ I ______ _ I 55722-26-4------octachlcro.biphenyl.~ ____ l_--==~--- .;lDOO I 91-94-1---------3,3'-Dichlorobenzidine ___ l ______ _ I 117-81-7--------bis(2-Ethylhexyl)ph~halate I I 53742-07-7------Nonachlorobiphenyl ____ ::i--...,,....---- I 2051-24-3-------oecachlorobiphenyl _____ l __ ~""""-~-- .:iaoo .;icoo t I 117-84-o--------oi-n-octylphthalate _____ l ______ _ I 205-99-2--------Eenzo(b)fluoranthene ____ l ______ _ I 207-08-9--------Benzo(k)fluoranthene ____ l ______ _ I 50-32-8---------Benzo(a)pyrene _______ l ______ _ I 193-39-5--------Indeno(l,2,3-cd)pyrene ___ l ______ _ I 53-70-3---------Dibenz(a,h)anthracene ____ l ______ _ I 191-24-2--------Benzc(g,h,i)perylene ____ l I - ,------ ' FORM I HCE-3 --:· .. u. I I l.t. I LI,. I ~ I I ~ I I lA I I I ~ I LL I I I I I I I I 'k~ 0 ~t}-1 ? '- 268 lllF EPA SAHPI..E NO. HIGR CONCEN r.RATrON EXTRAC'!?.BLE ANALYSIS DATA SliEz.:T TDTATIVELI IOEN'tIF1EO COMPOUNDS I I Lab N~e: <!~a Ke{ Labs conL-act:: (tt-{Jl-7!./~S I 1Ylllt/'tg La.b Cede: C..c 111 REF case No. : Phase Type: WIL SAS No.: .3t,~r-S+~ SOG No.: BAA~9 7 Lab .Sample ID: Phase weight: /_ 0 I.ab File IO: > ~/IOI Final. E:xt--a.ct: VolUllle: (g) I (111.L) Date Received: 9-.21- ra Injec~ion Volume: I (uL) Cate Separated: ----- Conversion Factor: 10 Date Ertra.ct:ed: IL> -d, -g 'i· pH: '1d2.. Date Analyzed: /~ -//-8~ Number T:cs found: I~ ~l I I I I I ! I I I I I I COMPOCUD NAME =-======-----1--------------== l. ______ I C.-l ~i>bs+--+---kA ~ .... :zel'I.C- 2. ______ I e-++ .. , - 1 · ..... .,,......__.' 1<,.ouo, ""~-,wHl'f I ______ I ~- pre£;':.; '?-?n::c~~ry l-t1<4 I J. 4. -~-3; ... c:-.... z_.7_3 ___ 1 ,-~ t - =' - < 1 - nu.,fr'-,,~n. j;DZ"'i 5. ___ I _.I ,J. ... G ... -.;; ... , .... 4 ___ 1 I • "' A )J ., ' -.J I 6. ______ I :J&,{<e,rn,--4--' --;;1e 0 -,.-e,; .... F =- c ''"'4r'-l I 7. ______ I -r:,..,.,..<U",v "-i.:;:'r 3wur-,< MF== r· ,, ~ 1<1 I a. ------' d,h,,hc-r.: .. --1-L,I-J::,den&, M~~r,c ~12, I 9. 10. 11. 12. 1:l. 14. l.5. l.6. l. 7. l.S. l.9. 20. 21. 22. 23. 24. 2S. 26. 27. 28. 29. _, __ ,_2 ... ~r .... ,3 ___ 1 J>c ds:c~, ~.e ....., I ______ I flf\tQl"•k"' AIYq>4 MF-:-C.13H2R ! ______ I '.1."to~4... I ______ ! 4::lh,.. 1,lr,., - .-1 '·'J-.. .• I - :C,do,, MF=-Ctt H/4 I ______ t lLnl'..'(\r,,·c r,ycl~c:,,rh;;-n MF'=-½t3H2fl ______ ! <4f>'-'-~,.1;,I ',-..,e-4-Lf C,:.,.ofr+fy 1,"e, I ------' '~rr-·,·:, A1v2:0,' M£=CllJl·l<C I ------' lLt\ tc,:\bc' ,.,, .• , ., f...,,,..(rrr .. rhyr. I I . I ------, ______________ ! ------'--------------' ------'--------------' ------'--------------' ------'--------------' ------'--------------' ------'--------------' ------'--------------' ------'--------------' ------'--------------' ------'--------------' ------'--------------' JO. ------'--------------' -------'--------------' ._, f FORM :I HCE-T:IC RT q . .1~ q, cJ:3 '9-51 ~-~~ ltJ. l1.. ~-S:l.,e. /~. (£(, 11..;.23 l :i. ll 12. 3~ I.J. SJ t;J, .. £{ £J.. fS:: /<+ • .J!, . ,s_ 1.,q ,,, . '1.2.. ~4 ... EST. CONC. I (mg/Kg} I I Q . .: I I i-1(.JC I ;;r: ' ·zM I ::r I I 7.2a I ;:i: I /~(;Q. I .:r I 1./,2/2. I :r: I -:i_l,() I ~ I ~IQ I :..! I J./9() I 0 I /,'J..O I :aJ I :s'.~'2 ! ::r ! 300 I :::r I -.2. 'i,(.) I :r I ~~Q I ;;r_ I ::2.iD I ;:r: I IIQ.u I X. I 15CJD I ;;r:_ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ~~ a,,/lrp I:_:! ()() :L ··~, .. \ ,' <:.) I I I I I I I I I I I ! I ! I I I I I I I I I I I l I I I I I I I I • ...___ 113 l.HA EPA SAMPLE NO. HIGH CONCENTRATION VOLATILE ANALYSIS DATA SHEET C gore,\. Lt4b Name: L~\:,-s Contract: w::t>:0\-3:~16 :i?>AAQ99 3'10O.t. Lab Code: Ceacef case No.: SAS No.: c...e+Z.S SDG No.: °BAAQ93- Phase Type: \ti.)°I .. L Lab Sample .ID: Phase weight: 1-D (g) Lab File ID: ') A \\:?:>9 Final Extract Volwne: lQ-0 (mL) Date Received: ~!22\8~ Aliquot Volume: ID (uL) Date Separated: ------ Conversic~ Factor: _,.5~-~D"---- Date Analyzed: 1olx\i~ CONCENTRATION c:..s NO. COMPOUND (mg/Kg) I 74-87-3---------Chloro~et.!:ane -------- ~QI 74-83-9---------5rc~c:e-chane ----- -So I 75-01-4---------Vinyl Chloride ---- Sol 1 75-00-3---------Chloroet..~ane ________ --------c. 5ol I 75-09-2---------Methylene Chloride _________ ..........:;;;....:,, .z. =;, I 5ol I 67-64-1---------Acetone ________________ _,:,, I 75-15-o---------carbon Disulfide ------ b51 1 75-35-4---------1,1-Dichloroethene ----- Z:,I 1 75-34-3---------1,l-Dichloroethane ----- 251 1 540-59-0--------1,2-0ichloroethene (total)_ I 67-66-3---------Chlorofor::i ------=-2:51 :251 ! 107-06-2--------1,2-Dichloroethane ----- :.Z.51 ' 73-93-3---------2-Butanone _________ -------==- 5pl ! 71-55-6---------1,l,l-Trichloroethane ---- 251 ' 56-23-5---------carbon Tetrachloride ---- .2.';:> I 1 108-05-4--------Vinyl Acetate _______ _ I 75-27-4---------Bromodichlorometilane -----~ Z5 I 251 I 78-87-5---------1,2-Dichloropropane _____ ------~ .ZSI J 10061-01-5------cis-l,3-0ichloropropene __ _ I 79-01-6---------Trichloroethene _____ .-., 251 ..l-51 I 124-48-1-------Dibromochloromethane ---- 1 79-oo-s---------1,1,2-Trichloroethane ---- 2:51 .2..5 ' 71-43-2---------Benzene - I u 1 10061-02-6------trans-l,3-Dichloropropene l_...;_ ___ -=-:-'-- 1 75-25-2--------Bromoform _________ -_-~l _____ ..=.....t.... 2.'o 1-0 I 108-10-1--------4-Methyl-2-Pentanone ____ l _____ .....:....~ 50 I 591-78-6--------2-Hexanone _ _,... _______ l _____ ..,.l,, I 127-18-4--------Tetrachloroethene ______ l ______ ~~ 50 &:=> I 79-34-5---------1,l,2,2-Tetrachloroethane l_..,....... __ __,ji=--~ I 108-88-3--------Toluene -,_,~~...u..:0:..----- 1 108-90-7--------Chlorobenzene ________ l __ ,,_ _ _.:;:.-,c:_ 2,-5 2;:> I 100-41-4--------Ethylbenzene ________ l_,Y_,..Q~Q,._ ___ _ I 100-42-5--------styrene ___________ l_....._ ____ _ I 1330-20-7-------Xylene (total) _______ ! 1~0 , ________________________ , .......... _._ ___ _ Q ~ ~ L.b.. ~ I.& LA._ ,~ ~ l,!,,,, ,~ LA- I li. LA- !:::!. ' .&. LA- I.!. I ,I, £...6.. L.b. u LA.... :s: !id L.&. !A L.6... ~ L"--- (A__. :s I I I I I I I I I I I I I I I I I I I I I I I I I I I I l I I l I I I I FORM I HCV i.)01 ·::· ..... ~: ~-~ () 1UT ~·· Jiff • \ '-- 114 lHE EPA S~LE NO. HIGH CONCENTRATION VOLATILE ANALYSIS DATA SHEET TDrrATIVELY IDENTIFIED COMPOUNDS L 40 N~e: C. ,Q ace \:: L O,XJ$ Contract: (.p ~ -0\ --)4{p'::> 7?;,A AO 5 s r 3~001:. Lab Code: Ce.acet case No. : --- SAS No. : se+z.S SOG No. : ""BA Ao9_1- Phase Type: WT,L Phase weight: l.0 Final Extract Volu:e: Aliquot: Volume: ,a (g) 10 .Q (tiL) (UL) Conversion Fac~or: S • 0 Number TICs found: _9 ____ _ Lab Sample ID: Lab File ID: ) A \\"';¾9 Date Received: 9lr2. \ ~\ Date Separated: ----- Date Analyzed: 1ol:=r\~ I EST. CONC. I I c.~.s NUMBER I CO:-'..Pot.P.1D NAME I RT I (mg/Kg} I Q I 1===========!======--===========--==1==---=1==========1=---1 I 2... ______ I~ • ~\.t,q\ n11ozeo:e. I 2).2+ I '8Cc0 I :S I I 2 • ______ ! ~cicnf.;o,d 'B iDZt'M I l:1 .~9 I 3J-O I :S I I J • ______ ltc: coetby 1 ::I:2eozelli" I 22, 3) I ,300 I .:s I I .; . ______ I :±c·, CC:€ ... b'f I ]:;;..e en-a<. I 2 3, 1{3 I 3 '10 I .;5 I s. ____ l~~~~yJ ~~~I"~ -I l";,-9-l- I -"-1:il> I ;s I 6. ______ 1 J. yl ~ y L Q]fN I Z':¼,l3:: I .560 I :s I --._I 7 • ______ ! €t'oy! ct roetn,d e:eoUM I ½ · 10 I :Y".1 o I ;s I 1 s. ______ l~e,cef".'e±½,11 n101eN, I 2(,, l?:- I :'::tQO I :S- I I 9. ______ IC-1 ::,ub::1:+.d:ed, :BeozeM I 21 ,1:X I :2.~o I :S I I 10 • _____ I ____________ I ___ I ______ I __ I I 11. _____ I ____________ I __________ I __ I I 12 • _____ ! ____________ ! __________ ! __ ! I 13 . _____ ! ____________ ! __________ ! __ ! I 14 • _____ ! ____________ ! _________ I __ I I 15. _____ I ____________ ---- ______ I __ I I 16. _____ I ______________________ I __ I I 17 . ______ ! _______________________ I __ I I ia. _____ l ____________ ---- ______ I __ I I 19. _____ I ______________________ I __ I I 20. _____ I ____________ ---- ______ I __ I I 21. _____ I ______________________ I __ I I 22 • _____ ! ______________________ t __ l I 23 • _____ ! ______________________ I __ I I 24 • _____ ! ______________________ I __ I I 2s. _____ l ______________________ I __ I I 26. _____ I ____________ ---- ______ I __ I I 27 • _____ ! ______________________ ! __ ! I 2s. _____ l ____________ ---- ______ I __ I I 29. _____ I ______________________ I __ I I JO. _____ , ____________ ----------'--' I _______ ! ___________________ I __ I , FORM I -HCV-TIC ,, Ot=- lHB 306 EPA SAMPLE NO. HIGH CONCENTRATION EXTRACTABLE ANALYSIS DATA SHEET :.ab Name: C.. 'n 12., ( Lt:. b S Contract: ~g-01-1✓1,5 Lab Code: Ctn}ll€€ Case No.: SAS No. : .3YWI-.5;,t2.S SOG No. : BAADf? Phase Type: ~HL Lab Sample ID: Phase weight: I .0 (g) Lab File ID: '>Cl /t) Z. .. Final Extract Volume: J. 0 (mL) Date Received: _i:_ 2 /- 1i 'i - Injection Volw:ie: I (UL) . Date Separated: Conversion Factor: 20 Date Extracted: ltJ-t-gt :£:H: (,.0 Date Analyzed: /t,-11- ri - CONCENTRATION CAS NO. CC!-!POtJND (mg/Kg) Q I I 108-95-2--------?henol _________________ _ I lll-44-4--------bis(2-Chlc=oetllyl)ether --- 1 95-57-8---------2-Chlorophenol ________________ _ I 541-73-1--------1,3-Dichlorobenzene ______________ _ I 106-46-7--------1,4-Dichlorobenzene ----- 1 lOO-Sl-6--------Benzyl alcohol _____________ _ I 95-50-1---------1,2-Dichlorobenzene --- 1 95-48-7---------2-Methylphenol ________________ _ I 108-60-l--------bis(2-Chloroisopropyl)ether I 106-44-5--------4-Met.~ylphenol - ______ _ I 621-64-7--------N-Nitroso-di-n-propylamine --- 1 67-72-1---------Hexachloroethane _____ =: ______ _ \ 98-95-3---------Nitrcbenzene --- 1 78-59-l---------Isophorone ________________ _ I 88-75-5---------2-Nitrophenol --- 1 105-67-9--------2,4-Dimethylphenol ----- 1 65-85-0---------aenzoic acid. ________ l _________ _ I lll-9l-l--------bis(2-Chloroethoxy)methane I ______ _ I 120-83-2-------2,4-Dichlorophenol ____ ::i ,--- 1 120-a2-1--------1,2,4-Trichlorobenzene ___ l I __ _ I 91-20-3---------Naphthalene-=---________ I I I 106-4 7-8-------4-Chloroaniline_..--------' ,--- 1 87-68-3-------Hexachlorobutadiene _____ l I I 59-50-7---------4-Chloro-3-methylphenol ___ l ,--- 1 91-57-6---------2-Methylnaphthalene _____ l I __ _ I 77-47-4---------Hexachlorocyclopentadiene I I I BB-06-2---------2,4,6-Trichlorophenol -I ,--- 1 95-95-4---------2,4,5-Trichlorophenol ____ l I __ _ I .91-58-7-------2-Chloronaphthalene _____ l I I 88-74-4---.:-----2-Nitroaniline _______ l 1--- 1 131-11-3--------Dimethylphthalate ______ l I __ _ I 208-96-8--------Acenaphthylene _______ l -1 I 606-20-2--------2,6-Dinitrotoluene _____ l 1--- 1 • . I ,~ I __ FORM :I HCE-lf reVA,(p_~ • ·• ·I !._.i!.) . .t - 307 lHC EPA SAMPLE NO. HIGH CONCENTRATION EXTRACTABLE ANALYSIS DATA SHEET Lab· Na!'!e: C,-,, /l.i { L 4 h~ La.i..1 Code: C. Cff)fh F case No. : Phase Type: lJ IL Phase weight: , .. 0 Final Extract Volume: Injection Volume: conversion Factor: pH: /.i.O CAS NO. (g) ....:.....-1.0 .... (m.L) / {UL) 2-0 CO!'!POUND Contract: &8-0 /-1</t,5 BA Ao'i1 SAS No. : 3ftii,z;:-$( ,- 25" SOG No. : 8AA~~7 Lab Sample IO: Lab File IO: °'::>c/1()2. Date Received: 'J._- 21-g <:j Date Separated: Date Extracted: I /J -~ -8 g Date Analyzed: 10-11·'38 CONCENTRATION (mg/Kg) Q I I 99-09-2---------3-Nitroaniline _______ l I 83-32-9---------AcenaDht~ene ,------- I s1-2a-s---------2,~-olnit=ophenol ______ l ---, 100-O2-7--------4-Nitrophenol ________ l I 132-64-9--------Dibenzofuran-,,. _______ I I 121-14-2--------2,4-Dinitrotoluene _____ l I 84-66-2---------Diethylphthalate,__..,....._,.. __ I I 7OO5-72-3-------4-Chlorophenyl-phenylether_l I 86-73-7---------Fluorene.....,.........,. ________ I I 10O-O1-6--------4-Nitroaniline _ _,..-=-_,...--,,-' I 534-52-1--------4,6-Dinitro-2-methylphenol I I 86-30-6---------N-Nitrosodiphenylamine (1)-1 I 101-55-3--------4-Bromophenyl-phenylether -, I 319-84-6--------alpha-BHC . ......,.. _______ ::_:, JoO L{.. I 118-74-1--------Hexachlorobenzene ______ l I 319-85-7--------beta-BHC. __ .,...__...,,.-_____ I JCµ u.. I 87-86-5---------Pentachlorcphenol . ......,.. _____ I I 58-89-9--------gamma-BHC (Lindane) _____ I ·::icv L.'- I a s-o 1-8---------Phenanthrene ________ I·. I 120-12-7-------Anthracene. _________ l I 319-86-8-------delta-BHC __________ I ,;200 LL I 76-44-8---------Heptachlor _________ l ,2QQ '-'- I 309-00-2--------Aldrin._-.-.-.-:-------'- ;J(>o u_ I 84-74-2---------Di-n-butylphthalate _____ l I 2O6-44-O-------Fluoranthene ________ l I 1O24-57-3-------Heptachlor epoxide _____ l ..:2Do u_ I 27323-18-a------Monochlorobiphenyl _____ l I ooo u.. I 2051-60-7-------Dichlorobiphenyl. ______ l Ii) oo LL I I 2051-61-8-------Trichlorobiphenyl . .._,,. _____ I 1 D OQ L..c.. I I 2051-62-9--.=----Tetrachlorobiphenyl _____ l I ooo LL I f 129-OO-O--------Pyrene_----------' I I 5103-74-2-------gamma-Chlordane _______ l ..:ion ~ ~ I '------=-------:-----::~--=~-=-----::---......----1 I I (1) - cannot be separated from Diphenylamine -t,V 7 FORM J: HCE-2 f .~ • \ -.:·- -·- .:,-.. 308 lHD EPA SAMPLE NO. HIGH CONCENTRATION EX':'RACTA13LE ANALYSIS DATA SHEET Lab Na:..ie: clb Q, { I ,4 b :S contract: {;t;-t;/-7t/t,5 Lab Code: (EnJ{l£F Case No.: SAS No. :3ftcr-s,t-J SOG No.: 13,AAo17 Phase Type: w rL-- Lab Sample ID: Phase weight: I . (g) Lab File ID: >ct 1~2 Final Extract Volw:ie: l- D (mL) Date Received: tr-21-fg Injection Volume: I (uL) - Date Separated: Conversion Factor: zo Date Extracted: ltrl,·f:T> pH: &·D Date Analyzed: l~ ·11-gg CONCENTRATIO!f C,;\S NO. c=~:CL'1I:J (.mg/Kg) Q I 959-98-8--------~~ccsulfan I -------- ;;co I l<. 5103 - 7 l - 9 - - - - - - - alt'~ a - Chlordane ------- :JOO I '-l. 25429-29-2------Pentac~lorobiphenyl ____ _ 72-55-9---------4,4'-DDE __ .....__ ___ _ IODQ I v.. .:JCQ I ~ 60-57-1---------Dieldrin ---------- 26601 - 64 - 9 - - - - - - Hex a ch lo rob i phenyl ____ _ .:JOO I ~ I I ODD I L.c.. I 72-20-a---------Endrin --.;......;,-=--.._ __ 33213-65-9------Endosulfan II -------- 72-54-8---------4,4'-DDD ---,--,--------- .:.Jco ,~, ,10D I u (<-10// .:i oo 28655 - 71 - 2 - - - - - - Hep tac~ lo rob i phenyl _______ __,:..,i ___ _ IQQO 1..1... I 85-68-7---------Butylbenzylphthalate __________ _ I 1031-07-B-------E~dosulfan sulfate ----- ..:ioo L'- I 50-29-3---------4,4'-DDT 53494-70-5------Endrin k_e_t_o_n_e _______ _ __ ...=,..:.,:;..:::;...._ __ .:JOO LA I ..:ioo ~ I 56-55-3---------Benzo(a)anthracene ____________ _ I 72-43-5---------Methoxychlor -------- ..:> 00 l-c. I 218 - 0 l - 9 - - - - - - - - C hry sen e ---------- 55722 - 26 - 4 - - - - - -o ct a ch lo rob i phenyl ----- 91 - 94 - 1 - - - - - - - - - 3, 3 ' - Di ch lo robe n z id in e --- I ..:.lCDb I.A I I ' 117-81-7--------bis(2-Ethylhexyl)phthalate I 53742-07-7------Nonachlorobiphenyl - - ----,.___,;;;_.;;,_;...;::;.._ __ I 2051-24-3-------oecachlorobiphenyl ____ _ I ::iooo LI.. I .:),{){)() L-'.. I I 117-84-0--------Di-n-octylphtha-late ___________ _ I I 205-99-2--------aenzo(b)fluoranthene __________ _ I f 207-08-9-------Benzo(k)fluoranthene __________ _ I I 50-32-8---------aenzo(a)pyrene _____________ _ I f 193-39-5--------Indeno(l,2,3-cd)pyrene _________ _ I I 53-70-3--------Di.benz(a,h)anthracene __________ _ I 191-24-2--------Eenzo(g,h,i)perylene ___ _ I I I I - - ~~ ~V~"VJV'- f FORM I HCE-3 ,-o •1·u 1· ,:,u: 2:::,H4 • ..____. - 1BF HIGH CONc:ENTRAnON EXTRACT.ABLE ANALYSIS DATA SHEE' TEHTATivELY IOENT:tFIEO COMPOUNDS Lab N:Une: t~a R,{ .L6. hs Contract: u!_-C!I Lab Code: C.c/lJl_fF case No.: SAS No. : .3f P~£'-,5t Phase Type: W/l La.b Sam Phase weight: L,.Q (g) La.b Fil., Final Extract Volume: I (mL) Date Rec Injec~ion Volume: I (uL) Date Set= Conversion Factor: pH: &.O 20 Date Date Ext Ana. Numbe=- T:Cs found: ..J[;. i I I c;i.s NUMBER I COMPOUND NAME RT 1= I l. =-==-,=----! ______ ! C~ .,(.Lbs+,+,.,J.,,) Ji n-zeJU. /('.t.,I I 2. ------' d,t,..,, ,Irr -::,u.LJ. ,,l-3,ozc:N 1/. :Jc I 3. I 4. I s. I 6. f.c.1"1 7~7 I 7. ______ ! domi:i+,,(- 1c0-1'Yi.·,,1,:+4,~C-3rroz:r:N I J.:).t)q ______ ! "'4A:S...:~<fr:) ~d:b•,{ d 14,-,b,i.t., lcu l / 1'.9''1 I ,J \ L , , ' I I I '<t'C!x''-'-,·! ~-,,001:"" SN Mf~C12H/:1. (,./<( _..;;;;...:. _______ I ti< l'lt,a':tfc::...-;;;o'e I -?c. <1'1 I ------' l.w.jo 1'•· Q /-,.,.A CC:C-t rhco I ..Jt:>.51/ I I 8. ______ I L<-,.., 1tQ r. '-xD At V.:. Dr< C::i F - OS H.38 I .:n ,;;;g I I 9. ---=_;;;..;~---' f.J,-",;,4cc,,c, I ,J.!J.;JS: I &.:i~<:t..JS I 10. ------=---------' E 1cc<4cv I :J</-57 I_ //.H'S$ I 11. ______ I H,» t rv I ;c t·i-4 .A [•'C 3 rbc C I ..:JS Q{o , _ I 12. ______ I <..L--. 1 c 1'11""' ti.:, ,;.,;,cr+cb"""'- I .:JS'. S:t./ I_ I lJ. ______ I 4:::--tr,ru n ~lt£..N MF_- C'l I Hc.(t+ l JS. fs3 J _ I 14. wtc"'JC 14 1r~ I Jtp.:JI./. I_ I 15. w--V a c w-.-.,, A I K,.,, o&-r I :Jt, • 30 I _ I 16. I 17. u.. ..... to"•••o I ..;,t,.~J I_ 4,-.... tocwh e: I t'..t+o-< I ~?- 'IS' I_ I 18. IN>t,1c1i,a Ait'.C!N: I ~S:-5:<t '- I 19. kt-cc, Kot'w A1 t:.*w I .:Jf. r, 7 I_ I 20. %to cw:n A It 4-<X I .3Q. ?Q I_ I 21. I 22. I 23. _____________________ , ____ !_ ------ ______________ ! I_ ------ ______________ ! I_ I 24. I 25. I 26. I 27. I 28. , 29. ____________________ ! I_ ------ ______________ ! I_ ------ ---------------' '- ------ ---------------' I_ _____________________ ! I_ ---------------------' '- JO. --------------------' '- -------- ______________ ! I_ o--v ~ ,u FORM 1·ur 001 • REFERENCE NO. 22 ~-- ' .. -- ESSO TUTU SERVICE STATION REVISED August, 1988 SOIL GAS VAPOR SCREENING SURVEY REPORT ST. THOMAS, U.S. V. I. JUNE 1 4, 198d PREPARED FOR ESSO STANDARD OILS.A. LTD. PREPARED BY BELGODERE & ASSOCIATES INC. 142 F.D. ROOSEVELT AVENUE HATO REY, PUERTO RICO 00918 (809) 756-6930 (809) 759-8818 BROOKMAN ROAD ST. THOMAS, U.S. V. I. 00802 (809) 774-1648 ~ I i I I - BAI personnel began the soil vapor screening survey for benzene, toluene, ethylbenzene and xylenes (BTEX). The initia1 screening investigation was completed on April 23. 1988. The su~vey results show an area of petroleum hydrocarbon vapor concentrations with levels ranging from not detectable (ND) to 1,675 ppm of benzene in the south and central portion of the ETSS facility. Immediately to the south ot the ETSS property the vapor concentrations were signiticantly reduced. A second area ot petroleum hydrocarbon vapor concentrations ranging trom ND to 128 ppm of benzene was obtained offs i te in an area adjacent to the west and southwest of the station. A third area of petroleum hydrocarbon vapor concentrations ranging from ND to 2.5 ppm of benzene was found throughout the remaining sampling stations. Although chlorinated compounds are not associated with motor fuel storage and dispensing operations. DPNR-EPA requested ESSO to include in the soil vapor screening survey analyses of the following chlorinated hydrocarbons: dichloroethylene (DCE), tetrachloroethylene (PCE). trichloroethylene (TCE). This request was made by the agencies because chlorinated compounds were reported in the _groundwater and found in a previous soil vapor survey conducted in the area. This investigation showed that chlorinated hydrocarbon vapors were present in most of the points sampled. 2 1 iJT 001 :.::::uu .. I I I?-" A soil vapor survey was conducted at the Texaco service station. The Texaco service station is located 600 ft. upgradient from the ETSS taci<l-ity. A report of their finding was submitted on December 18, 1987, to the regulatory agencies . 2.0 PROJECT BACKGllOU11D A number of water wells have been shut down by the Department of Planning and Natural Resources of the USVI (DPNR) and the Environmental Protection Agency Region II, New York (EPA) as a result of reported groundwater contamination in the Tutu area of St. Thomas, USVI. DPNR/EPA believe that among the possible sources of aromatic hydrocarbons found in the groundwater may be the gasoline stations which operate or had operated in the Tutu area. Esso, as- the owner of a gasoline service station located in the Four Winds Shopping Center at the Tutu Area of St. Thomas, was issued an administrative order by DPNR to investigate the site. Esso contracted BAI to conduct the investigation and to issue a report on the findings. ESSO and BAI representatives met several times with EPA's Project Managers, Hr. Charles Dolan, who was subsequently replaced by Ms._ Caroline Kwan; DPNR's representatives, Ms. Francine Lang and Gregory Rhymer; and the Project Officer from - Camp, Dresser & McKee Federal Programs Corporation (CDH-FPC), Mr. Scott B. Graber, to discuss the technical approach to be used in the investigation. 3 /1,r uu1 RESULTS OF SOIL GAS SURVEY 4.1 AllOMTIC BYDROCAllBOIIS Table 4.1.1 presents the highest BTEX analyses results of the sequen~ial samples obtained from each soil vapor sample point. Sequential samples were taken during the survey instead ~ of duplicate split samples originally proposed in the Wor~ Plan. Copies ot all chromatograms and daily calibration curves are presented in a separate supplement entitled: "Photocopies of Original Gas Chromatograms and Calibration Curves". At the drift point selected for the ETSS soil vapor investigation, repeated samples were taken by inserting separate probes within an area of less than 150 square feet to determine whether soil vapor values varied signiticantly over time and short distance. A total ot 7 drift point values for BTEX and chlorinated hydrocarbons were obtained during 7 of the 14 sampling days. (See tables 4.1.2A and 4.1.2B for results and figure 3.1.1 for location). Drift point benzene values ranged between < 1 ppm and 160 ppm. (The highest value recorded was trom a sa~ple obtained from a depth of 6 ft.) The range of values obtained in the drift point area may be in part controllea by the inability_ to obtain samples trom the same depth along with the time and spacial differences that could naturally occur. Depth achieved for any sampl1ng point was controlled by local lithology. 15 iU\ 0 U 1 "/ .:, '7/ O t Values reported in tables 4.1 .1 and 5 .0.1 are the calculated values without subtracting background and/or drift point values. The soil vapor screening survey identitied three areas of measurable ijTEX vapor concentrations: o Area 1 - Service station property and area south of property. Benzene vapor concentrations ranged from ND to 1,675 ppm. o Area 2 - West and southwest of service station. Benzene vapor concentrations ranged from ND to 128 ppm. o Area 3 - North and east of the service station. Benzene vapor concentrations ranged from ND to 2.5 ppm. Figure 4.1.3 presents a distribution map of benzene, toluene and xylenes soil vapor results found during this study. Due to unavailability of a gaseous atandard for E-benzene, no values for this compohent are reported in this study. Contour map~ of soil vapor concentrations for total BTEX, benzene, toluene and xylenes are pres e_n ted in · f-igures 4. 1 . 4, - 4.1.5, 4.1.6 and 4.1.7 respectively. The contour maps have been derived from values obtained from the soil gas survey and do not constitute concentrations of hydrocarbons in the soil or groundwater of the area in question. 16 ,., .-,• !i..,,if (_i()J :2.:~,C.}J_ (')CATION ., • p. 1 .P.2 ). p. 3 .P.4 "'. F '----' .J.P.6 .P.7 Table 4.1.2 A VALUES SHOWING HIGHEST CONCENTRATION OF AROMATIC HYDROCARBON VAPORS,. ESSO TUTU AREA (PPM) DATE DEPTH BENZENE TOLUENE M-P-XYLENE O-XYLENE 4/6/88 8 IO II ND ND ND ND 4/7/88 6 'O" 160.679 ND ND ND 4/8/88 3 I 6 11 ND NO NO ND 4/11/88 6 I 8" ND ND ND NO 4/12/88 6' 0" ME ND ND ND 4/13/88 7' 0" ND 0.660 ND 5.880 4/14/88 6'3.5" ND 0.964 0.984 0.330 ME MASKING EFFECT ND NOT DETECTED , 9 TU I UO .1 2 .::·'/',:: f-·· Table 4.1.2 B VALUES SHOWING HIGHEST CONCENTRATION OF CHLORINATED HYDROCARBON VAPORS, ... ESSO TUTU AREA (PPM) LOCATION DATE DEPTH DCE TCE PCE D. p • 1 4/6/88 8' 0 11 NO ND ND O.P.2 4/7/88 6' 0 11 NO ND ND O.P.3 4/8/88 3 I 6 11 NO NO NO D.P.4 4/11/88 6 I 8 II ND NO NO D.P.5 4/12/88 6 'O" NO· NO 3.064 D.P.6 4/13/88 7' O" NO ND NO D.P.7 4/14/88 6 1 3.5 11 22.16 0.104 0.196 ND NOT DETECTED 20 r \_ : · r l) l) 1 · .'.:, ,:.? .. :\ HRS s @ Swrlace w111t Ao"t• Score 1S,w> 0 -~ s2 • s2 • s2 QW SW I ✓ si • sl • s2 QW SW l Vs! • s~ • s~ / 1.11 • s,.. wW SW I WORKSHIIT ,roR COMPUTING SM PRO J 2 2 s, •• ·- ••• ✓ 12 • 12 • 12 QW SW I " J J J / s,. • • .. • s. 1.fJ s • ly • WORKSHIIT ,011 COMPUTING SM (P ,,1 _ f 4t 1 ,}- ~ __j -/-7.L l~v, ;v;. I s' .,. , 7' e ~ / -~ 0-· 7 fl ... 11 UU :t l\. OJ (l] [lJ Gl '.-- 13] [!] [!l ~roui,a wa1er Aou1e wor• Snfft .i.u,qi,ea v••u• C,rct• Or,11 I li41.1111o I · '.4•a 1 :11er I HRS I S:=r~ 1 PRO Otlteft.0 Ae,eaae @ ,~ 1 I 01 ,, I 4!{" 1, oaae~eo r•••u• •• o•••" 1 score ot •s. s:iroc8" 10 1,ne G]. II ooser,H r•••M 11 ;nren I score or o. 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