Edwards-Trinity (Plateau) Aquifer | Texas Water Development Board

Edwards-Trinity (Plateau) Aquiferinteractive map | cross-section

Aquifer Facts

  • Aquifer type: mostly unconfined with small confined areas
  • Area of outcrop: 32,373 square miles
  • Area of subsurface: 3,051 square miles
  • Proportion of aquifer with groundwater conservation districts: 82 percent
  • Number of counties containing the aquifer: 41

Summary

The Edwards-Trinity (Plateau) Aquifer is a major aquifer extending across much of the southwestern part of the state. The water-bearing units are composed predominantly of limestone and dolomite of the Edwards Group and sands of the Trinity Group. The saturated thickness of this aquifer system increases from less than 100 feet in the north to greater than 800 feet down-dip to the south. Freshwater saturated thickness averages 433 feet.

Springs occur along the margins of the aquifer where the water table intersects the ground surface. San Felipe Springs is the largest exposed spring along the southern margin. Springs also discharge groundwater along the eastern flanks of the Trans-Pecos Mountains; the lower Pecos River canyons in Del Rio are the largest of these springs. As water levels have declined in the western portion of the aquifer due to increased irrigation pumping, springflows in those areas have also declined. In addition, many small springs that once flowed throughout the plateau have ceased flowing as a consequence of native grasslands being replaced by woody vegetation that consumes large amounts of potential recharge and allows more rainfall to run off before it is able to recharge the aquifer.

The water in the Edwards-Trinity (Plateau) Aquifer is generally a hard, calcium bicarbonate type and typically has total dissolved solids concentrations ranging from 400 to 1,000 milligrams per liter. Water quality in the unconfined portion of the aquifer is generally fresh, with only small, localized areas of slightly saline groundwater. Water typically increases in salinity to the west within the Trinity Group and in the confined portion of the aquifer where the groundwater is generally slightly to moderately saline.

More than two-thirds of groundwater pumped from this aquifer is used for irrigation, with the remainder used for municipal and livestock supplies. Water levels have remained relatively stable because recharge has generally kept pace with the relatively low amounts of pumping over the extent of the aquifer.

Reports

ID Date Type Description
Texas Aquifers Study 12/31/2016 Legislative Report Texas Aquifers Study: Groundwater Quantity, Quality, Flow, and Contributions to Surface Water
HA-03 1/1/1995 Hydrologic atlas Water Quality in the Edwards-Trinity (Plateau) Aquifer, Edwards Plateau and Trans-Pecos, Texas
R-317 1/1/1990 TWDB numbered report Evaluation of Ground-Water Resources in Parts of Loving, Pecos, Reeves, Ward and Winkler Counties, Texas
R-255 9/1/1980 TWDB numbered report Occurrence and Quality of Ground Water in the Edwards-Trinity (Plateau) Aquifer in the Trans-Pecos Region of Texas
R-356 12/1/2001 TWDB numbered report Aquifers of West Texas
LP-214 2/1/1995 Limited publication Evaluation of Ground-Water Quality in Texas Counties Bordering the Rio Grande
AA08-06 6/17/2009 Aquifer assessment Desired future condition scenarios for the Edwards-Trinity (Plateau) Aquifer - Glasscock, Reagan, Upton and Midland counties
B-6212 7/1/1962 Groundwater bulletin Geology and Ground-Water Resources of Uvalde County, Texas
B-6216 12/1/1962 Groundwater bulletin Geology and Ground-Water Resources of Kinney County, Texas
B-6210 5/1/1962 Groundwater bulletin Ground-Water Geology of Bandera County, Texas
R-047 5/1/1967 TWDB numbered report Occurrence and Quality of Ground Water in Crockett County, Texas
R-050 6/1/1967 TWDB numbered report Ground-Water Resources of Mitchell and Western Nolan Counties, Texas
R-235 7/1/1979 TWDB numbered report Occurrence, Availability, and Chemical Quality of Ground Water in the Edwards Plateau Region of Texas
R-296 11/1/1986 TWDB numbered report Carbonate Geology and Hydrology of the Edwards Aquifer in the San Antonio Area, Texas
R-102 11/1/1969 TWDB numbered report Ground-Water Resources of Kerr County, Texas
R-029 9/1/1966 TWDB numbered report Base-Flow Studies, Upper Guadalupe River Basin, Texas, Quality and Quantity
R-353 9/1/2000 TWDB numbered report Groundwater Availability of the Trinity Aquifer, Hill Country Area, Texas: Numerical Simulations through 2050
R-360 2/9/2004 TWDB numbered report Conference Proceedings: Aquifers of the Edwards Plateau
R-224 10/1/1978 TWDB numbered report Occurrence, Quantity, and Quality of Ground Water in Taylor County, Texas
R-346 3/1/1996 TWDB numbered report The Paleozoic and Related Aquifers of Central Texas
R-339 8/1/1992 TWDB numbered report Evaluation of Ground-Water Resources of the Paleozoic and Cretaceous Aquifers in the Hill Country of Central Texas
R-330 7/1/1991 TWDB numbered report Evaluation of Ground-Water Resources in the Southern High Plains of Texas
B-6519 8/1/1965 Groundwater bulletin Ground-Water Conditions in Menard County, Texas
B-6208 4/1/1962 Groundwater bulletin Ground-Water Geology of Edwards County, Texas
R-078 5/1/1968 TWDB numbered report Ground-Water Resources of Upton County, Texas
R-132 8/1/1971 TWDB numbered report Water Well and Ground-Water Chemical Analysis Data, Schleicher County, Texas
R-145 4/1/1972 TWDB numbered report Water Wells and Ground-Water Chemical Analysis Data, Reagan County, Texas
R-146 4/1/1972 TWDB numbered report Water Well and Ground-Water Chemical Analysis Data, Irion County, Texas
R-148 5/1/1972 TWDB numbered report Water Well and Ground-Water Chemical Analysis Data, Sterling County, Texas
R-166 3/1/1973 TWDB numbered report Ground-Water Resources of Coke County, Texas
R-172 6/1/1973 TWDB numbered report Ground-Water Resources of Val Verde County, Texas
GR11-013_MP 10/4/2011 GAM run - Management Plan Management plan information for Menard County UWCD
AA06-01 6/10/2008 Aquifer assessment Water-level decline scenarios for the Capitan Reef Complex, Marathon, Rustler, Presidio-Redford Bolson, Edwards-Trinity (Plateau), and Diablo Plateau aquifers in Groundwater Management Area 4
AA09-12 8/31/2010 Aquifer assessment Desired future condition scenarios for the Edwards-Trinity (Plateau) Aquifer in Groundwater Management Area 4
GR11-003_MP 7/29/2011 GAM run - Management Plan Management plan information for Santa Rita UWCD
GT10-033 1/3/2011 GAM task Average drawdown for the Edwards-Trinity (Plateau) and Pecos Valley aquifers within management zones in Middle Pecos GCD
GR10-026_MP 8/24/2010 GAM run - Management Plan Management plan information for Sterling County UWCD
GT10-027_D 2/9/2011 GAM task Predictive simulations for the Edwards (Balcones Fault Zone) and Edwards-Trinity (Plateau) aquifers in Kinney County GCD
GR10-022_MP 7/9/2010 GAM run - Management Plan Management plan information for Uvalde County UWCD
GR10-018_MP 7/27/2010 GAM run - Management Plan Management plan information for Menard County UWD
GR09-030_MP 10/21/2009 GAM run - Management Plan Management plan information for Cow Creek GCD
GR09-011 9/14/2010 GAM run Predictive simulations for the Edwards-Trinity (Plateau) and Trinity aquifers in Groundwater Management Area 9
GR09-012 9/14/2010 GAM run Predictive simulations for the Edwards-Trinity (Plateau) and Trinity aquifers in Groundwater Management Area 9
GR09-024 9/14/2010 GAM run Predictive simulations for the Edwards-Trinity (Plateau) and Trinity aquifers in Groundwater Management Area 9
GR09-011_S 9/13/2010 GAM run Predictive simulations for the Edwards-Trinity (Plateau) and Trinity aquifers in Groundwater Management Area 9
GR09-012_S 9/13/2010 GAM run Predictive simulations for the Edwards-Trinity (Plateau) and Trinity aquifers in Groundwater Management Area 9
GR09-024_S 9/13/2010 GAM run Predictive simulations for the Edwards-Trinity (Plateau) and Trinity aquifers in Groundwater Management Area 9
GR09-013_MP 8/6/2009 GAM run - Management Plan Management plan information for Wes-Tex GCD
GR08-086_MP 1/5/2009 GAM run - Management Plan Management plan information for Real Edwards Conservation and Reclamation District
GR09-035_D 8/7/2010 GAM run Predictive simulations for the Edwards-Trinity (Plateau) and Pecos Valley aquifers in Groundwater Management Area 7
GR08-075_MP 1/23/2009 GAM run - Management Plan Management plan information for Middle Pecos GCD
GR08-074_MP 12/9/2008 GAM run - Management Plan Management plan information for Kimble County GCD
GR08-052_MP 7/11/2008 GAM run - Management Plan Management plan information for Sutton County UWCD
GR08-051_MP 7/9/2008 GAM run - Management Plan Management plan information for Plateau UWC and Supply District
GR08-034_MP 5/28/2008 GAM run - Management Plan Management plan information for Hickory UWCD No. 1
GR08-033_MP 5/28/2008 GAM run - Management Plan Management plan information for Permian Basin UWCD
GR08-029_MP 5/28/2008 GAM run - Management Plan Management plan information for Jeff Davis County UWCD
GR08-027_MP 5/21/2008 GAM run - Management Plan Management plan information for Crockett County GCD
GR08-025_MP 5/21/2008 GAM run - Management Plan Management plan information for Glasscock GCD
GR08-013_MP 4/8/2008 GAM run - Management Plan Management plan information for Sterling County UWCD
GR08-012_MP 4/8/2008 GAM run - Management Plan Management plan information for Irion County WCD
GR08-008_MP 1/25/2008 GAM run - Management Plan Management plan information for Lipan-Kickapoo GCD
GR08-007_MP 4/29/2008 GAM run - Management Plan Management plan information for Headwaters GCD
GR07-039_MP 4/8/2008 GAM run - Management Plan Management plan information for Coke County GCD
GR07-037 4/9/2008 GAM run Predictive simulation for the Edwards-Trinity (Plateau) Aquifer in Groundwater Management Area 7
GR07-032 12/11/2007 GAM run Historic and predictive simulation for the Edwards-Trinity (Plateau) Aquifer in Groundwater Management Area 7
GR07-024_MP 9/5/2007 GAM run - Management Plan Management plan information for Cow Creek GCD
GR07-022_MP 6/5/2007 GAM run - Management Plan Management plan information for Santa Rita UWCD
GR07-010 3/23/2007 GAM run Recharge calculations for the Edwards (Balcones Fault Zone) and Edwards-Trinity (Plateau) aquifers in Kinney County GCD
GR07-008_MP 4/26/2007 GAM run - Management Plan Management plan information for Brewster County GCD
GR07-003 6/13/2007 GAM run Predictive simulation for the Edwards-Trinity (Plateau) Aquifer in Groundwater Management Area 7
GR06-016 2/2/2007 GAM run Effects on river flow of various pumping scenarios in the Edwards-Trinity (Plateau) Aquifer in Terrell and Val Verde countie
GR06-011_MP 7/12/2006 GAM run - Management Plan Management plan information for Real-Edwards Conservation and Reclamation District
GR05-037_MP 11/18/2005 GAM run - Management Plan Management plan information for Sterling County UWCD
GR05-030 7/15/2005 GAM run Recharge information for the Carrizo-Wilcox, Edwards-Trinity (Plateau) and Trinity aquifers in Uvalde County
GR05-008 2/17/2005 GAM run Water budget for Reagan County
GR05-007 2/11/2005 GAM run Recharge areas in Kinney County's portions of Edwards BFZ Aquifer and Edwards-Trinity (Plateau) Aquifer (Nueces River and Rio Grande basins)
GR04-018 10/7/2004 GAM run Recharge rates for the Trinity Aquifer in Hays Trinity GCD
GR04-017 10/7/2004 GAM run Recharge rates for the Edwards-Trinity (Plateau) Aquifer in Nolan County (Wes-Tex GCD)
GR03-016 8/11/2003 GAM run Average annual recharge and total available storage for the Edwards-Trinity (Plateau) Aquifer in Emerald UWCD
GR03-003 5/15/2003 GAM run Effects of increasing well production in western Midland county
AA08-05 10/22/2009 Aquifer assessment Desired future condition scenarios for the Edwards-Trinity (Plateau) Aquifer in Groundwater Management Area 7
GR12-006_MP 4/11/2012 GAM run - Management Plan Management plan information for South Plains UWCD
GR12-007_MP 6/13/2012 GAM run - Management Plan Permian Basin UWCD Management Plan
GR12-010_MP 7/2/2012 GAM run - Management Plan Management plan data for Lipan-Kickapoo WCD
GR12-009_MP 7/20/2012 GAM run - Management Plan Management plan data for Bandera County River Authority and Ground Water District
GR12-004_MP 7/20/2012 GAM run - Management Plan Management plan data for Crockett County GCD
GR08-026_MP 5/7/2008 GAM run - Management Plan Management plan information for Hill Country UWCD
GR12-023_MP 8/10/2012 GAM run - Management Plan Management plan data for Jeff Davis County UWCD
R-380 7/1/2011 TWDB numbered report Aquifers of Texas
GR12-021_MP 9/4/2012 GAM run - Management Plan Management plan data for Headwaters GCD
GR12-015_MP 9/4/2012 GAM run - Management Plan Management plan data for Hill Country UWCD
GR12-020_MP 10/19/2012 GAM run - Management Plan Management plan data for Glasscock GCD
CR-0904830820 4/1/2010 Contract report Application of PEST to Re-Calibrate the Groundwater Availability Model for the Edwards-Trinity (Plateau) and Pecos Valley Aquifers
GR12-019_MP 11/16/2012 GAM run - Management Plan Management plan data for Coke County UWCD
GR12-017_MP 11/16/2012 GAM run - Management Plan Management plan data for Irion County WCD
GR13-001_MP 1/24/2013 GAM run - Management Plan Management plan data for Blanco-Pedernales GCD
GR08-068_MP_Ver2 4/28/2010 GAM run - Management Plan Management plan information for Bandera County River Authority and Ground Water District
GR12-014_MP 2/11/2013 GAM run - Management Plan Management plan data for Kinney County GCD
GR13-012_MP 4/23/2013 GAM run - Management Plan Management Plan data for Terrell County GCD
GR13-018_MP 7/3/2013 GAM run - Management Plan Management Plan data for Kimble County GCD
GR13-005_MP 7/17/2013 GAM run - Management Plan Management Plan Information for Sutton County UWCD
GR13-009_MP 7/17/2013 GAM run - Management Plan Management Plan Information For Plateau UWCD and SD
GT13-026_TERS 9/19/2013 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 2
GT13-027_TERS 9/19/2013 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 3
GT13-030_TERS 10/2/2013 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 7
GT13-032_TERS 10/2/2013 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 9
GR13-020_MP 10/7/2013 GAM run - Management Plan Management Plan data for Brewster County GCD
GR13-029_MP 11/15/2013 GAM run - Management Plan Management plan data forCow Creek GCD
GR13-023_MP 12/18/2013 GAM run - Management Plan Management plan information for Real-Edwards Conservation and Reclamation District
GT13-028_TERS 1/15/2014 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 4
GR13-030_MP 2/18/2014 GAM run - Management Plan Management plan data for Wes-Tex GCD
GR14-010_MP 3/26/2014 GAM run - Management Plan Management Plan data for Middle Pecos GCD
GR15-008_MP 7/2/2015 GAM run - Management Plan Management plan data for Menard County UWCD
GR15-006_MP 6/26/2015 GAM run - Management Plan Management Plan data for Uvalde County UWCD
GR16-022_MP 6/16/2016 GAM run - Management Plan Management plan data for Comal Trinity GCD
GR16-013_MP 8/31/2016 GAM run - Management Plan Management plan information for Permian Basin UWCD
GR16-019_MP 9/17/2016 GAM run - Management Plan Management plan information for Headwaters GCD
GR17-028_MP 3/27/2017 GAM run - Management Plan Management plan information for Menard County UWD
GR17-012_MP 3/28/2017 GAM run - Management Plan Management plan information for Sterling County UWCD
GR17-022_MP 3/28/2017 GAM run - Management Plan Management plan information for Crockett County GCD
GR17-002_MP 4/4/2017 GAM run - Management Plan Management plan information for Santa Rita UWCD
GR17-005_MP 5/26/2017 GAM run - Management Plan Management plan information for Lipan-Kickapoo Water Conservation District
GR17-004_MP 11/29/2017 GAM run - Management Plan Management plan information for Bandera County RA&GD
GR17-009_MP 1/30/2018 GAM run - Management Plan Management plan information for Hill Country UWCD
GR18-003_MP 4/6/2018 GAM run - Management Plan Management plan information for Blanco-Pedernales GCD
GR18-001_MP 5/10/2018 GAM run - Management Plan Management plan information for Reeves County GCD
GR17-014_MP 6/1/2018 GAM run - Management Plan Management plan information for Coke County UWCD
GR13-010_MP 6/4/2018 GAM run - Management Plan Management plan information for Hickory UWCD no.1
GR18-007_MP 7/13/2018 GAM run - Management Plan Management plan information for Hickory UWCD #1
GR18-015_MP 9/28/2018 GAM run - Management Plan Management plan information for Kimble County GCD
GR18-022_MP 2/11/2019 GAM run - Management Plan Management plan information for Glasscock GCD
GR19-008_MP 2/27/2019 GAM run - Management Plan Management plan information for Brewster County GCD
GR19-011_MP 2/27/2019 GAM run - Management Plan Management plan information for Cow Creek GCD
GR19-012_MP 6/13/2019 GAM run - Management Plan Management plan information for Wes-Tex GCD
GR19-021_MP 2/20/2020 GAM run - Management Plan Management plan information for Middle Pecos GCD
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