ABSTRACT
Groundwater levels in the alluvial aquifer system underlying Lancaster, California, declined more than 60 m during the 20th century, resulting in about 2 m of land subsidence. Water managers are considering an aquifer storage and recovery (ASR) program to help meet growing demand while minimizing future land subsidence. The U.S. Geological Survey, in cooperation with Los Angeles County and the Antelope Valley-East Kern Water Agency, monitored a pilot ASR program, analyzed the effects on water levels and subsidence, and developed a simulation/optimization model to help plan and manage an ASR program. Simulated management scenarios ranged from maintaining present practices (no injection) to allowing injection for a maximum of six months per year in 16 existing and 13 proposed wells. Results of the simulation/optimization model suggest that phased installation of the proposed wells is needed to maintain production capacity and avoid subsidence during a 10-year management horizon.
