Seawater Intrusion Extraction Barrier

An experimental extraction-type sea water intrusion barrier was tested near Oxnard in Ventura County, California, to develop information on halting intrusion in the area and in other areas with similar hydrologic and geologic conditions. Major facilities of the barrier were 5 extraction wells, 25 piezometers, one anode well for cathodic protection, and a discharge pipeline. During the barrier test, intrusion was halted in the test area and the intruded area decreased in size from 6,200 acres (25,091,000 m²) to 4,800 acres (19,425,000 m²). However, because of inadequate extraction capacities at the pumping wells, it was not possible to lower the ground water levels at the extraction well line below the trough in the piezometric surface located inland of the test site. Difficulty was experienced with the cathodic protection system and use of noncorrosive materials is recommended. It was concluded an extraction-type barrier is technically feasible to halt intrusion in the Oxnard area.