Operating a Sea Water Barrier Project

A 1.5-mile section of fresh water barrier protecting a part of a coastal ground water basin in Los Angeles County has successfully been in operation for 10 yr. Several modifications have evolved in the basic design of recharge wells and appurtenant facilities. The existing facilities, and proposed changes for new works, are described. Cost information is included on the drilling of recharge and observation wells. Maintenance of barrier facilities has presented problems regarding corrosion of metallic materials and clogging of recharge wells. The methods of alleviating or dealing with these situations, or both, are examined and specific applications of non-metallic materials are described. Cost of maintenance is presented. The amount of supplemental chlorination required for continuous operation of the wells has been determined to be in the order of 2 mg per l. Factors contributing to clogging of the wells are examined and results of studies to evaluate the interrelationships of these factors are presented.