Techniques for Mapping and Characterizing Brackish Aquifers through the Mining of Existing Geophysical Data

Abstract

One challenge to the more widespread development of brackish groundwater in Texas is the lack of detailed information on brackish aquifers. In 2003, the Texas Water Development Board (TWDB) funded a study to determine brackish groundwater volumes in the state's 30 aquifers. The study estimated that Texas has approximately 2.7 billion acre-feet of brackish groundwater. However, the study was by design regional in scope, limited in areal extent, and narrow in its assessment of groundwater quality. In 2009, the 81st Texas Legislature approved funding to implement a program (now called the Brackish Resources Aquifers Characterization System or BRACS) to more thoroughly characterize the brackish aquifers in the state with the goal of assisting communities interested in exploring desalination as a water supply option. Since its inception, BRACS has built a formidable knowledge base of data on brackish groundwater resources in the state by analyzing and interpreting existing and available geophysical well logs and aquifer data. This data is managed in databases and geographic information systems (GIS). To date, the BRACS team has completed in-house studies for the Pecos Valley Aquifer, portions of the Gulf Coast Aquifer in the Lower Rio Grande Valley, and the Queen City and Sparta aquifers in Atascosa and McMullen counties and all study data are available on the TWDB website at http://www.twdb.texas.gov/innovativewater/bracs/index.asp. Ongoing in-house BRACS studies include the central region of the Upper Coastal Plains and Lipan aquifers, both of which will be completed in fall 2016. More recently, House Bill 30, passed by the 84th Texas Legislature in 2015 requires TWDB to identify, delineate, and report on brackish groundwater production zones in four aquifers (Blaine, Rustler, parts of the Carrizo-Wilcox, and Gulf Coast aquifers) by December 1, 2016. The Trinity, Blossom, and Nacatoch aquifers will have areas of potential brackish groundwater production delineated in fall 2017 and the remaining aquifers in the state before December 1, 2022.

AAPG Datapages/Search and Discovery Article #90250 © 2016 Southwest Section AAPG Annual Convention, Abilene, Texas, April 9-12, 2016