Edwards (Balcones Fault Zone) Aquiferinteractive map | cross-section

Summary

The Edwards (Balcones Fault Zone) Aquifer is a major aquifer in the southcentral part of the state. It consists primarily of partially dissolved limestone that creates a highly permeable aquifer. Aquifer thickness ranges from 200 to 600 feet, and freshwater saturated thickness averages 560 feet in the southern part of the aquifer.

The groundwater, although hard, is generally fresh and contains less than 500 milligrams per liter of total dissolved solids.

The aquifer feeds several well-known springs, including Comal Springs in Comal County, which is the largest spring in the state, and San Marcos Springs in Hays County, which is the second largest. Hueco, San Pedro, San Antonio, and Leona springs also discharge from the aquifer. Because of the aquifer's highly permeable nature, water levels and spring flows respond quickly to rainfall, drought, and pumping.

Water from the aquifer is primarily used for municipal, irrigation, and recreational purposes. San Antonio obtains almost all of its water supply from the Edwards (Balcones Fault Zone) Aquifer. Although water levels periodically and seasonally decline rapidly in wells throughout the aquifer, they also rebound quickly with adequate rainfall.

Reports

ID Date Type Description
LP-214 2/1/1995 Limited publication Evaluation of Ground-Water Quality in Texas Counties Bordering the Rio Grande
GMA8_DFC_01 12/17/2007 DFC submission Desired future conditions for the Blossom, Brazos River Alluvium, Edwards (Balcones Fault Zone), Nacatoch, and Woodbine aquifers
GMA10_DFC_02 8/4/2010 DFC submission Desired future conditions for the fresh and saline Edwards Aquifer
GMA13_DFC_02 8/12/2010 DFC submission Desired future conditions for the Edwards and Yegua-Jackson aquifers
B-6212 7/1/1962 Groundwater bulletin Geology and Ground-Water Resources of Uvalde County, Texas
B-5911 10/1/1959 Groundwater bulletin Ground-Water Geology of Bexar County, Texas
R-019 3/1/1966 TWDB numbered report Ground-Water Resources of Guadalupe County, Texas
R-340 7/1/1992 TWDB numbered report Model Refinement and Applications for the Edwards (Balcones Fault Zone) Aquifer in the San Antonio Region, Texas
R-350 11/1/1999 TWDB numbered report Changes in Groundwater Conditions in the Edwards and Trinity Aquifers, 1987-1997, for Portions of Bastrop, Bell, Burnet, Lee, Milam, Travis, and Williamson Counties, Texas
B-5601 8/1/1956 Groundwater bulletin Geology and Ground-Water Resources of Medina County, Texas
B-6216 12/1/1962 Groundwater bulletin Geology and Ground-Water Resources of Kinney County, Texas
B-6004 8/1/1960 Groundwater bulletin Geology and Ground-Water Resources of Hays County, Texas
R-032 12/1/1966 TWDB numbered report Ground-Water Resources of Atascosa and Frio Counties, Texas
R-234 6/1/1979 TWDB numbered report Geohydrology of Comal, San Marcos, and Hueco Springs
R-296 11/1/1986 TWDB numbered report Carbonate Geology and Hydrology of the Edwards Aquifer in the San Antonio Area, Texas
R-239 10/1/1979 TWDB numbered report Ground-Water Resources and Model Applications for the Edwards (Balcones Fault Zone) Aquifer in the San Antonio Region
R-325 4/1/1990 TWDB numbered report Test Well Drilling Investigation to Delineate the Downdip Limits of Usable-Quality Ground Water in the Edwards Aquifer in the Austin Region, Texas
R-276 6/1/1983 TWDB numbered report Occurrence, Availability, and Quality of Ground Water in Travis County, Texas
R-353 9/1/2000 TWDB numbered report Groundwater Availability of the Trinity Aquifer, Hill Country Area, Texas: Numerical Simulations through 2050
R-358 12/1/2003 TWDB numbered report Groundwater Availability Modeling: Northern Segment of the Edwards Aquifer, Texas
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
GR10-015_MP 6/15/2010 GAM run - Management Plan Management plan information for Evergreen UWCD
GR10-009_MP 6/9/2010 GAM run - Management Plan Management plan information for Clearwater UWCD
GR09-019 6/1/2011 GAM run Predictive simulations for the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 10
GR08-067_MP 9/3/2008 GAM run - Management Plan Management plan information for the Edwards Aquifer Authority
GR08-062_MP 9/3/2008 GAM run - Management Plan Management plan information for Evergreen UWCD
GR08-060 7/11/2008 GAM run Simulation of discharge to springs and streams in the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 8
GR08-059 7/11/2008 GAM run Simulation of discharge to springs and streams in the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 8
GR08-037_MP 6/20/2008 GAM run - Management Plan Management plan information for Barton Springs/Edwards Aquifer Conservation District
GMA8_DFC_05 4/27/2011 DFC submission Desired future conditions for the Blossom, Brazos River Alluvium, Edwards (Balcones Fault Zone), Ellenburger-San Saba, Hickory, Marble Falls, Nacatoch, Trinity, and Woodbine aquifers
GR07-021 10/30/2007 GAM run Simulation of discharge to springs and streams in the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 8
GR07-015 10/30/2007 GAM run Simulation of discharge to springs and streams in the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 8
GR07-010 3/23/2007 GAM run Recharge calculations for the Edwards (Balcones Fault Zone) and Edwards-Trinity (Plateau) aquifers in Kinney County GCD
GR06-033 2/12/2007 GAM run Effects on springflow and river flow of various pumping scenarios in the San Antonio Segment of the Edwards (Balcones Fault Zone) Aquifer
GR06-030 4/18/2008 GAM run Simulation of discharge to the Leona Gravel Aquifer from the Edwards (Balcones Fault Zone) Aquifer
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)
AA10-35_MAG 11/20/2011 Aquifer assessment MAG Modeled available groundwater estimates for the saline Edwards Aquifer in the Northern Subdivision of Groundwater Management Area 10
GR08-010_MAG 4/3/2008 GAM run - MAG Managed available groundwater estimates for the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 8
GR10-065_MAG 12/14/2011 GAM run - MAG Modeled available groundwater estimates for the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 8
GR12-002_MAG 7/24/2012 GAM run - MAG Modeled available groundwater for the Edwards (Balcones Fault Zone) Aquifer in Groundwater Management Area 10 for Kinney County
AA10-35_MAG 11/20/2011 Aquifer assessment MAG Modeled available groundwater for the saline Edwards Aquifer in the Northern Subdivision of Groundwater Management Area 10
R-380 7/1/2011 TWDB numbered report Aquifers of Texas
AA10-40_MAG 8/20/2012 Aquifer assessment MAG Modeled available groundwater for the Edwards Aquifer in Frio County
CR-1004831114 8/9/2012 Contract report Ground Water Recharge Model: Calibration and Validation for Remotely-Sensed Dual Coefficient (RDC) GMA8 ET Estimation
GR10-059_MAG_Ver2 12/7/2011 GAM run - MAG Modeled available groundwater for the Edwards (Balcones Fault Zone) Aquifer in the Northern Subdivision of Groundwater Management Area 10
GR12-014_MP 2/11/2013 GAM run - Management Plan Management plan data for Kinney County GCD
GT13-032_TERS 10/2/2013 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 9
GT13-033_TERS 8/20/2013 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 10
GT13-036_TERS_Ver2 7/15/2013 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 13
GT13-031_TERS 1/15/2014 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 8
GR15-009_MP 3/18/2015 GAM run - Management Plan Management Plan data for Edwards Aquifer Authority
GR15-004_MP 6/30/2015 GAM run - Management Plan Management Plan data for Evergreen UWCD
GR15-003_MP 11/24/2015 GAM run - Management Plan Management Plan data for Clearwater UWCD
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