Southern California Coastal water resource subregion

The Southern California coastal subregion, sometimes called the South Coast Hydrologic Subregion, is a second-level subdivision[1] covering is approximately 11,000 sq mi (28,000 km2; 7,000,000-acre) and extends from Rincon Creek on the north to the international border with Mexico on the south.

The federally-defined Southern California Coastal water resource subregion equates roughly with the state-designated South Coast hydrologic region.

Per a USGS report of 1976, "Water deficiency is prevalent in the South Coastal subregion.

"[3] By 1955 the region was found to be experiencing measurable levels of saltwater intrusion due to overdrawn aquifers and several wells were abandoned as a consequence.

[3] Part of the solution was injecting Colorado River water from the aqueduct into local wells to defend against the salted water, a practice called artificial recharge.