After World War II , the population of Southern California increased dramatically .
Groundwater in the area had been over-exploited to the point of creating saltwater intrusion from the Pacific Ocean , rendering the local groundwater non-potable .
After World War II , the population of Southern California increased dramatically , and groundwater in the area had been over-exploited to the point of creating saltwater intrusion from the Pacific Ocean , rendering the local groundwater non-potable .