GEOHyVROLOGy OF THE DELAWARE 8ASIH AND VICINITy, TEXAS AND HEW AtEXICO By Steven F. Richey, Jane G. Wells, and Kathleen T. Stephens U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 84-4077 Prepared in cooperation with the U.S. ENVIRONMENTAL PROTECTION AGENCY Albuquerque, New Mexico 1985 UNITED STATES DEPARTMENT OF THE INTERIOR DONALD PAUL MODEL, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director For additional information Copies of this report can write to: be purchased from: Open-File Services Section District Chief Branch of Distribution U.S. Geological Survey U.S. Geological Survey, MS 306 Water Resources Division Box 25425, Denver Federal Center 505 Marquette NW, Room 720 Denver, Colorado 80225 Albuquerque, New Mexico 87102 (303) 236-7476 COMTENTS Page Abstract .......................................................... I Introduction ....................................................... 3 Geohydrologic setting ............................................... 3 Geohydrology of the aquifers ......................................... 9 Capitan aquifer ............................................... 9 Structure and thickness .................................... 9 Ground-water occurrence and use ........................... 9 Recharge and discharge ................................... 10 Aquifer-test data ......................................... II Water quality ............................................ II Rustler Formation ............................................. 12 Structure and thickness .................................... 12 Ground-water occurrence and use ........................... 13 Recharge and discharge ................................... 14 Aquifer-test data ......................................... 14 Water quality ............................................ 15 Santa Rosa Sandstone .......................................... 16 Structure and thickness .................................... 16 Ground-water occurrence and use ........................... 17 Recharge and discharge ................................... 18 Aquifer-test data ......................................... 19 Water quality ............................................ 19 Aquifers in Cenozoic alluvium ................................... 19 Structure and thickness .................................... 20 Ground-water occurrence and use ........................... 20 Recharge and discharge ................................... 21 Aquifer-test data ......................................... 22 Water quality ............................................ 22 Summary ......................................................... 23 References ........................................................ 25 in CONTENTS - Concluded Page Supplemental information .............................................. 33 Glossary of geohydrologic terms .................................. 33 Wel l-numbering systems ......................................... 37 New Mexico .............................................. 37 Texas .................................................... 37 Well-numbering system used in this report .................... 39 Parts per million and milligrams per liter .......................... 39 Definition of saline water ........................................ 41 ILLUSTRATIONS Figure I. Map showing location of the Delaware Basin, study area, and regional structural features ............................... 4 2. Generalized east-west geologic section of the Delaware Basin study area .............................................. 6 3. Generalized geologic sections of the WIPP site and vicinity ................................................. 8 4. Diagram showing system of numbering wells in New Mexico ..... 38 5. Diagram showing system of numbering wells in Texas ........... 40 PLATES [ In pocket ] Plate I. Map showing geology of the Delaware Basin, Texas and New Mexico 2. Map showing selected wells, water levels in, and thickness of the Capitan aquifer, Texas and New Mexico 3. Map showing selected wells and water levels in the Rustler Formation, Texas and New Mexico IV PLATES - Concluded [In-Pocket] Plate 4. Map showing selected wells, water levels in, and thickness of the Santa Rosa Sandstone, Texas and New Mexico 5. Map showing selected wells and water levels in aquifers in Cenozoic alluvium, Texas and New Mexico 6. Map showing saturated thickness of aquifers in the Cenozoic alluvium, Texas and New Mexico TABLES Page Table I. Water-level records of wells in the Delaware Basin and vicinity, including availabilities of water analyses and aquifer tests .......................................... 43 2. Analyses of water from selected wells in the Capitan aquifer ................................................... 62 3. Analyses of water from selected wells in the Rustler Formation ................................................ 65 4. Analyses of water from selected wells in the Santa Rosa Sandstone ................................................ 69 5. Analyses of water from selected wells in aquifers in the Cenozoic alluvium ......................................... 73 6. Aquifer-test data for selected wells in the Capitan aquifer ................................................... 86 7. Aquifer-test data for selected wells in the Rustler Formation ................................................ 87 8. Aquifer-test data for selected wells in the Santa Rosa Sandstone ................................................ 87 9. Aquifer-test data for selected wells in aquifers in Cenozoic alluvium ......................................... 88 10. Summary of geologic units and water-bearing properties for the Delaware Basin and vicinity .......................... 90 TABLES'- Concluded Page Table II. Public water supplies in the Delaware Basin study area ......... 95 12. Water-level trends taken from water-level data in the Delaware Basin .......................................... 97 13. Ground-water pumpage in I960 from the Capitan aquifer, Rustler Formation, Santa Rosa Sandstone, and aquifers in Cenozoic alluvium in the Delaware Basin and vicinity in Texas ..................................... 98 14. Average dissolved-solids concentrations of samples of Pecos River water, Carlsbad, New Mexico, to Girvin, Texas, for water year October 1979 to September 1980 ........ 99 COHV£RSIOH FACTORS In this report, measurements are given in inch-pound units only. The following table contains factors for converting to metric units. Multiply inch-pound units by To obtain metric units inch 25.40 millimeter foot 0.3048 meter foot per day 0.3048 meter per day foot squared per day 0.0929 meter squared per day foot cubed per day 0.02832 meter cubed per day mile 1.609 kilometer acre-feet 1.233 x 10 cubic hectometers gallon per minute 0.06309 liter per second gallon per minute liter per second per foot 0.2070 per meter Chemical concentrations are given in metric units as weight-per-weight units of parts per million (ppm, one milligram of solute per kilogram of solution) and as weight-per- volume units of milligrams per liter (mg/L). VI GEOHYDROLOGy OF THE DELAWARE BASIH AND VICINITV, TEXAS AND NEW MEXICO By Steven F. Richey, Jane G. Wells, and Kathleen T. Stephens ABSTRACT The Delaware Basin study area includes all or part of Crane, Culberson, Loving, Pecos, Reeves, Ward, and Winkler Counties, Texas, and Eddy and Lea Counties, New Mexico. Major aquifers in the Delaware Basin are the Capitan aquifer, Rustler Formation, Santa Rosa Sandstone (Dockum Group), and aquifers in the Cenozoic alluvium. The Capitan reef complex (Capitan aquifer) consists of the Capitan and Goat Seep Limestones and includes in ascending order, the Grayburg, Queen, Seven Rivers, Yates, and Tonsil I Formations of the Artesia Group. Water from the Capitan aquifer is used for domestic and irrigation purposes in Eddy County, New Mexico, and for irrigation and industrial purposes in Texas. Available analyses indicate that dissolved-solids concentrations range from 303 to 31,700 milligrams per liter, chloride concentrations range from 16 to 16,689 milligrams per liter, and fluoride concentrations range from 0.5 to 3.0 milligrams per liter. The Rustler Formation contains water that generally is not suitable for domestic use because of its salinity. Chloride concentrations range from 15 to 210,000 milligrams per liter, and dissolved-solids concentrations range from 286 to 325,800 milligrams per liter. Fluoride concentrations range from 0.5 to 11.4 milligrams per liter. Water from this aquifer is used for irrigation and stock watering where it is of suitable quality. The Santa Rosa Sandstone is the principal source of ground water in the western third of Lea County and in the eastern part of Eddy County. In parts of Texas, the Santa Rosa Sandstone and the Cenozoic alluvium are hydraulically connected and are called the Allurosa aquifer. The Santa Rosa Sandstone-Allurosa aquifer is the source of municipal supply for the cities of Barstow, Pecos, Monahans, and Kermit, Texas. Water quality is variable. For those analyses where the Santa Rosa Sandstone is a distinct entity, chloride concentrations range from 10 to 4,800 milligrams per liter, dissolved-solids concentrations range from 205 to 2,990 milligrams per liter, and fluoride concentrations range from 0.4 to 5.0 milligrams per liter. Water from the Cenozoic alluvium is used extensively for public water supplies, irrigation, industry, livestock watering, and rural-domestic supply throughout the Delaware Basin. The majority of the population in the study area