Ellenburger-San Saba Aquiferinteractive map | cross-section

Aquifer Facts

  • Aquifer type: confined and unconfined
  • Area of outcrop: 1,152 square miles
  • Area of subsurface: 4,279 square miles
  • Proportion of aquifer with groundwater conservation districts: 80 percent
  • Number of counties containing the aquifer: 16

Summary

The Ellenburger−San Saba Aquifer is a minor aquifer that is found in parts of 16 counties in the Llano Uplift area of Central Texas. The aquifer consists of the Tanyard, Gorman, and Honeycut formations of the Ellenburger Group and the San Saba Limestone Member of the Wilberns Formation. The aquifer consists of a sequence of limestone and dolomite that crop out in a circular pattern around the Llano Uplift and dip radially into the subsurface away from the center of the uplift to depths of approximately 3,000 feet. Regional block faulting has significantly compartmentalized the aquifer. The maximum thickness of the aquifer is about 2,700 feet.

Water occurs in fractures, cavities, and solution channels and is commonly under confined conditions. The aquifer is highly permeable in places, as indicated by wells that yield as much as 1,000 gallons per minute. Numerous springs issue from the aquifer, maintaining the baseflow of streams in the area.

Groundwater in the Ellenburger-San Saba Aquifer is generally very good and usually has less than 1,000 milligrams per liter of total dissolved solids. Total dissolved solids increase down-dip and radially outward from the Llano Uplift, centered in Llano County. Elevated concentrations of radionuclides also occur in the aquifer, mostly in the northern part of the aquifer.

Most of the groundwater is used for municipal purposes, and the remainder for irrigation and livestock. A large portion of water flowing from San Saba Springs, which is the water supply for the city of San Saba, is thought to be from the Ellenburger-San Saba and Marble Falls aquifers.

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
B-6310 12/1/1973 Groundwater bulletin Reconnaissance Investigation of the Ground-Water Resources of the Brazos River Basin, Texas
R-046 5/1/1967 TWDB numbered report Occurrence and Quality of Ground Water in Brown County, Texas
R-057 9/1/1967 TWDB numbered report Occurrence and Quality of Ground Water in Coleman County, 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-174 7/1/1973 TWDB numbered report Ground-Water Resources of Blanco County, Texas
R-360 2/9/2004 TWDB numbered report Conference Proceedings: Aquifers of the Edwards Plateau
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
B-6519 8/1/1965 Groundwater bulletin Ground-Water Conditions in Menard County, Texas
CR-1004831116 7/11/2012 Contract report Aquifer Test and Related Well Information from Public Water Supply Wells in Groundwater Management Area 8
R-380 7/1/2011 TWDB numbered report Aquifers of Texas
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
GT13-031_TERS 1/15/2014 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 8
GR16-006_MP 6/21/2016 GAM run - Management Plan Management plan information for Central Texas GCD
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
GR17-009_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
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
GR19-005_MP 3/15/2019 GAM run - Management Plan Management plan information for Saratoga UWCD
Top