Enhancing Recharge in the Edwards Aquifer, Texas: Measures, Outcomes, and Lessons for Karst Aquifers

Managed aquifer recharge is a widely adopted method that involves storing excess water underground for future use. While managed aquifer recharge has been applied globally to different aquifer types, its use in karst aquifers is less common due to the unique hydrogeological characteristics of these systems, including high permeability, variable water flow velocities, and shorter water residence times. Consequently, there is a gap in studies assessing managed aquifer recharge effectiveness in karst aquifers. The Edwards Aquifer in south-central Texas, which provides water to over 2 million people, is an example where recharge enhancement strategies have been explored. This study synthesizes enhanced recharge measures in the Edwards Aquifer from the 1960s to 2024, assessing their benefits, limitations, and regulatory frameworks guiding these strategies. By reviewing state water codes, rules, articles, technical reports, and case studies, this study reveals purpose and methods of recharge enhancement in the region. Findings suggest that while recharge dams, designed for flood control, have contributed to enhancing recharge, their impact remains marginal compared to natural recharge volumes. Aquifer storage and recovery emerged as a key strategy to store Edwards water in other stable aquifers and the brackish zone of the Edwards Aquifer. Recirculation and springflow augmentation were explored but not implemented due to uncertainties. Other initiatives focused on enhancing the quality of water entering the aquifer. Enhanced recharge in karst aquifers (or using karst aquifers' water to enhance recharge in other aquifers) is important as societies continue to face challenges due to population growth and environmental changes.