Groundwater Recharge for Drought and Endangered Species Protection

Abstract

San Antonio Water Systems (SAWS) developed its H2Oaks aquifer storage and recovery project in response to pumping restrictions set on its primary source of water supply, the Edwards Aquifer. The H2Oaks project pumps water from the Edwards Aquifer during wet years and transports it to the H2Oaks project site, where it is injected into the Carrizo-Wilcox aquifer for storage. Stored water is withdrawn to meet municipal demand when restrictions on Edwards Aquifer pumping are in place. Although created for the purpose of securing supplies for SAWS, the H2Oaks project became a centerpiece for regional water management. Storage is used during drought to mitigate impacts on pumping while ensuring minimum springflows needed to protect endangered species in the Edwards aquifer. Currently, the project stores over 176,000 acre-feet of water. This case study traces the development of the H2Oaks project from the passage of the Edwards Aquifer Act to the project’s current implementation. The H2Oaks project demonstrates the potential for groundwater recharge projects to store water as protection against drought conditions. It also demonstrates how storage by one entity can support water management needs across the broader community of water users.