Ground-Water Conditions in the Rincon and Mesilla Valleys and Adjacent Areas in New Mexico By C. S. CONOVER GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1230 Prepared in cooperation with the Elephant Butte Irrigation District UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1954 UNITED STATES DEPARTMENT OF THE INTERIOR Douglas McKay, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price $1.50 (paper cover) CONTENTS Page Abstract............................ ................................................................................................. 1 Introduction............................................................................................................................ 4 Purpose and scope of investigation................................................................................ 4 Previous investigations.................................................................................................... 5 Acknowledgments.............................................................................................................. 7 Well-numbering system...................................................................................................... 8 Features of the area.............................................................................................................. 10 Location and general features........................................................................................ 10 Climate................................................................................................................................ 12 Topographic features........................................................................................................ 15 Rio Grande Project.......................................................................................................... 17 Geology.................................................................................................................................. 21 Character of sediments.................................................................................................... 22 Thickness of sediments.................................................................................................... 24 Occurrence of ground water in upland areas...................................................................... 27 Depth to water.................................................................................................................... 27 Movement and flow of ground water................................................................................ 31 Recharge of ground water................................................................................................ 37 Water conditions inthe Rincon.and Mesilla Valleys........................................................ 38 Surface water...................................................................................................................... 38 Available surface flow.................................................................................................. 38 Diversions to canals of Rio Grande project.............................................................. 40 Distribution of diversions............................................................................................ 40 Unit diversions.......................................................................................................... 41 Canal waste................................................................................................................ 41 Canal-seepage losses.............................................................................................. 42 Water delivered to farms.......................................................................................... 43 Flow of drains in Rincon and Mesilla Valleys.......................................................... 43 Relations of drain flow and diversions...................................................................... 45 Required water supply...................................................................................................... 50 Ground water in valley fill.............................................................................................. 52 Depth to water................................................................................................................ 52 Fluctuations of the water table.................................................................................. "58 Effect of irrigation.................................................................................................... 58 Effect of precipitation.............................................................................................. 64 Effect of transpiration.............................................................................................. 65 Source and movement of ground water........................................................................ 65 Direction of movement.............................................................................................. 65 Source of ground water.............................................................................................. 66 Seepage from the Rio Grande................................................................................ 66 Seepage from canals.............................................................................................. 73 Recharge from irrigation water............................................................................ 76 Recharge from precipitation................................................................................. 77 Discharge of ground water........................................................................................ 77 Chemical quality of water.................................................................................................... 79 General features................................................................................................................ 79 Variation of quality with depth........................................................................................ 82 Variation of quality areally.............................................................................................. 84 Quality of Las Graces water supply................................................................................ 88 Summary of quality of water.............................................................................................. 89 Hyd»ologic characteristics of water-bearing formation.................................................... 90 General conditions............................................................................................................ 90 Coefficient of transmissibility........................................................................................ 90 Methods of determining................................................................................................. 90 Pumping tests................................................................................................................ 92 Water-table gradients and flow of drains.................................................................... 96 Specific yield...................................................................................................................... 10 2 III TV 1V CONTENTS Page Ground-water development................................................................................................... 103 Previous development........................................................................................................ 103 Present development.......................................................................................................... 105 Domestic supplies.......................................................................................................... 105 Irrigation supplies.......................................................................................................... 107 Performance of existing wells..................................................................................... 107 Future development............................................................................................................ 110 Pumping of ground water.................................................................................................. 114 General conditions........................................................................................................ 114 Effect of pumping upon flow of drains........................................................................ 116 Supplemental pumping of ground water in a drought period...................................... 121 Pumping of ground water with a normal supply of surface water............................ 128 Cost of pumping'supplemental ground water.............................................................. 129 Recommended location of wells.................................................................................. 130 Recommendations for future studies.................................................................................... 132 Summary.................................................................................................................................. 133 Literature cited.....................................................................................................................