An Aquifer Storage and Recovery system with reclaimed wastewater to preserve native groundwater resources in El Paso, Texas

The traditional concept of Aquifer Storage and Recovery (ASR) has been emphasized and extensively applied for water resources conservation in arid and semi-arid regions using groundwater systems as introduced in Pyne's book titled Groundwater Recharge and Wells. This paper extends the ASR concept to an integrated level in which either treated or untreated surface water or reclaimed wastewater is stored in a suitable aquifer through a system of spreading basins, infiltration galleries and recharge wells; and part or all of the stored water is recovered through production wells, dual function recharge wells, or by streams receiving increased discharge from the surrounding recharged aquifer as needed. In this paper, the author uses the El Paso Water Utilities (EPWU) ASR system for injection of reclaimed wastewater into the Hueco Bolson aquifer as an example to address challenges and resolutions faced during the design and operation of an ASR system under a new ASR system definition. This new ASR system concept consists of four subsystems: source water, storage space-aquifer, recharge facilities and recovery facilities. Even though facing challenges, this system has successfully recharged approximately 74.7 million cubic meters (19.7 billion gallons) of reclaimed wastewater into the Hueco Bolson aquifer through 10 recharge wells in the last 18 years. This ASR system has served dual purposes: reuse of reclaimed wastewater to preserve native groundwater, and restoration of groundwater by artificial recharge of reclaimed wastewater into the Hueco Bolson aquifer.