Assessing Groundwater Storage Changes in Edwards-Trinity Aquifer, Texas

Existing water supplies in Texas are projected to decline by about 18 percent by 2060, a trend caused primarily by increases in water demand and depletion of aquifers. The Edwards-Trinity regional aquifer system, a 200,000-km2 carbonate and clastic rock aquifer extending from southeastern Oklahoma to western Texas, provides water to all or parts of 38 counties in Texas. The extensive use of the Edwards-Trinity Aquifer has already resulted in relatively large artesian pressure declines near population centers. Although numerous studies have been conducted on the Edwards-Trinity aquifer system, significant uncertainty remains about the spatiotemporal replenishment characteristics of the aquifer. The U.S.-German Gravity Recovery and Climate Experiment (GRACE) satellite mission provides a unique opportunity to infer terrestrial water storage (TWS) variations on a regional basis. Previous studies have demonstrated the viability of using GRACE-derived TWS anomalies to conduct water budget analysis at both regional and continental scales. The purposes of our study are to (a) assess the potential of using GRACE, North America Land Assimilation System data, and in situ measurements to infer groundwater storage variations in the Edwards-Trinity aquifer system and (b) utilize remotely sensed data for informed groundwater resources management. Our preliminary results indicate that GRACE-derived TWS anomalies correlate well with results obtained through other means and, thus, the GRACE data could be a valuable tool for further calibrating a regional groundwater availability model developed for the Edwards-Trinity aquifer system.