Edwards-Trinity (Plateau) aquifer: Structure and Brackish Groundwater

Study Summary:

The goals of the study are to (1) map and characterize the brackish parts of the Edwards-Trinity Plateau aquifer in greater detail using existing water well reports, geophysical well logs, and available aquifer data and (2) build datasets that can be used for groundwater exploration and replicable numerical groundwater models to estimate the volumes of groundwater in as many as five salinity classes. The study area includes all or parts of the following counties: Andrews, Bandera, Blanco, Brewster, Coke, Concho, Crane, Crockett, Culberson, Ector, Edwards, Gillespie, Glasscock, Howard, Irion, Jeff Davis, Kendall, Kerr, Kimble, Kinney, Martin, Mason, McCulloch, Menard, Midland, Mitchell, Nolan, Pecos, Reagan, Real, Reeves, Schleicher, Sterling, Sutton, Taylor, Terrell, Tom Green, Upton, Uvalde, Val Verde, and Winkler.

The objectives of the study are to:

  • collect, analyze, and interpret thousands of water well and geophysical well logs;
  • map the geological boundaries of the Edwards-Trinity Plateau aquifer;
  • map the distribution of total dissolved solids in the aquifer;
  • map the distribution of key chemical parameters of interest to desalination;
  • map the water bearing lithologic units in the aquifer;
  • estimate the volume of fresh and brackish water in the aquifers;
  • incorporate all information into the publicly available database and GIS datasets;
  • present study findings in a peer-reviewed TWDB report.
Study Manager:

Evan Strickland, P.G.

Study Team Members:

Sydney Weitkunat, P.G.

Pat Bryan

Approximate Study Start Date:
Spring 2017
Estimated Study Completion Date:
Winter 2025
The team anticipates that the publicly available data and report produced by this study will aid researchers and decision-makers in the selection or elimination of locations for site specific studies on groundwater desalination and aquifer storage and recovery. As stipulated by the 84th Texas Legislature in House Bill 30, it will also enable the process of evaluating the Edwards-Trinity Plateau Aquifer for the designation of brackish groundwater production zones and submitting a report to the Texas Legislature by December 1, 2032.

Study Details

Recent Meetings

Event Date
West Texas Geological Society poster presentation September 21, 2022




  • Paul Tybor, General Manager of the Hill Country Underground Water Conservation District - for providing Geophysical logs in Gillespie County.
  • The Midland Energy Library - for donating sample logs throughout the study area.
  • The Railroad Commission (RRC) Geology Advisory Unit (GAU) - for sharing their work on the Maverick Basin (Deep Glen Rose) aquifer.
  • Final Report

    • The final report is scheduled for completion in the winter of 2025.