Northern Trinity Aquifer: Structure and Brackish Groundwater

Study Summary:

The goals of the study are to (1) map and characterize the brackish parts of the Northern Trinity 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: Bastrop, Bell, Bosque, Bowie, Brown, Burnet, Callahan, Collin, Comanche, Cooke, Coryell, Dallas, Delta, Denton, Eastland, Ellis, Erath, Falls, Fannin, Franklin, Grayson, Hamilton, Henderson, Hill, Hood, Hopkins, Hunt, Jack, Johnson, Kaufman, Lamar, Lampasas, Lee, Limestone, McLennan, Milam, Mills, Montague, Morris, Navarro, Palo Pinto, Parker, Red River, Robertson, Rockwall, Shackelford, Somervell, Tarrant, Taylor, Titus, Travis, Williamson, Wise.

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 Northern Trinity 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:
Mark Robinson
Study Contributors:
Neil Deeds - INTERA, Inc.
Daniel Lupton - INTERA, Inc.
Approximate Study Start Date:
Winter 2017/2018
Estimated Study Completion Date:
Spring 2019
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 Northern Trintiy Aquifer for the designation of brackish groundwater production zones by March 2019.

Study Details


Study Investigators:

Texas Water Development Board
1700 N. Congress Avenue
Austin, TX 78711

Mark Robinson, P.G.

Engaged Stakeholders:

This list is not yet available.

Stakeholder Meetings

Event Date
Stakeholder meeting on the proposed potential production areas for the Trinity Aquifer in Austin, Texas May 8, 2017 at 11:00 a.m.
Stakeholder meeting on the brackish groundwater resources and final potential production areas for the Trinity Aquifer at the Brazos (Region G) Regional Water Planning meeting in Waco, Texas November 1, 2017 at 10:00 a.m.
Presentation at the 68th Annual Meeting of the Gulf Coast Association of Geological Societies in Shreveport, Louisiana October 2, 2018


Final Report