Managing a Water Supply Portfolio Using Groundwater Recharge and Extraction for a Southern California System

California’s climate varies greatly depending on latitude, elevation, and proximity to the coast. Southern California gets its water from various sources. Local groundwater sources provide between 30% and 40% of supply, and the remainder comes from surface water supplies and imported water from the Owens Valley, the Colorado River, and the State Water Project (SWP). This chapter presents a case study that sought to optimize the long-term sustainable management of local groundwater in southern California. It discusses the development of a Groundwater Basins Master Plan (GBMP), which includes evaluating potential opportunities to identify reliable sources of replenishment water to meet groundwater production demands in the West Coast and Central groundwater basins in southern California. The chapter includes screening-level cost estimates for the alternatives, allowing the determination of the value of these various water sources.