Impacts of Land Cover Change on Natural Recharge Levels in the Semi-Arid Edwards Aquifer Region of Texas

Understanding historical land cover and land use, and other related changes within the hydrologic signals of a region is advantageous when modeling efforts are considered. However, incorporating different types of land cover changes for hydrologic prediction is not a well-understood task. From a water resources planning and management perspective, this is of unique interest in semi-arid regions where water availability is often low and thus, water balance sensitivity may be high. The semi-arid Edwards Aquifer region of Texas has undergone measurable increases in both population and impervious surface area over the last twenty years, particularly in the greater metropolitan areas of San Antonio and Austin, the eighth and nineteenth largest cities in the United States, respectively. Consequently, it is expected that the hydrologic response of the Edwards Aquifer has also undergone changes. The Soil and Water Assessment Tool (SWAT) is a physically- based modeling tool for predicting the impacts of land management practices on water, sediment, and agricultural chemical yields. This work presents the results of an algorithm developed to utilize the SWAT model for estimating natural recharge levels in the semi-arid Edwards Aquifer region of Texas when land cover and land use, and other related system input changes are considered.