Saltwater Intrusion in the Coastal Aquifers of Los Angeles County, California

The Central and West Coast groundwater basins (CWCB) are two coastal aquifer systems located adjacent to the Pacific Ocean in southwestern Los Angeles County, California (Figure 1). Severe groundwater overdraft of these basins from the early 1900s to the late 1950s caused water levels to drop below sea level, allowing saltwater to intrude into the potable aquifers, knocking coastal wells out of service, and threatening the usability of this major water supply reservoir.