The San Diego County Water Authority has completed construction and testing of two 18-inch diameter wells that will help triple the current output of the city of Oceanside’s Mission Basin Desalter Facility starting in 2009. The new wells will each capture 1,600 gallons-per-minute of brackish groundwater from the Mission Basin, which normally flows into the ocean, and pump it a half-mile to Oceanside’s desalter facility. The new wells will bring the facility’s maximum output to 6.3 million gallons a day and provide 20 percent of Oceanside’s daily water needs.
“Developing new local sources of water helps us diversify our water supplies and ease our reliance on imported water,” said Water Authority Board Chair Fern Steiner. “These wells will bring us one step closer to having local groundwater supplies meet our goal of 7 percent of our county’s needs by 2020.”
In 2007, local groundwater accounted for 2 percent of the of the Water Authority’s water deliveries.
The two wells are expected to begin production once construction of the pump house and pipeline connecting the wells to the desalter facility are complete by early 2009. The groundwater has salt content roughly three times higher than the Water Authority’s imported water supply. It will be treated at the desalter facility to remove its mineral content and 1, 2, 3-trichloropropane. TCP is a contaminant recently discovered in the western portion of the Mission Basin.
“TCP has curbed our plant’s daily production rate, but installation of carbon filters and water from the new wells will allow us to bring the plant to full capacity,” said Greg Blakely, administration manager, city of Oceanside Water Utilities Department. The filters are expected to be in place by July 2008.
The Water Authority built the wells as part of the city of Oceanside’s Mission Basin Project and the Water Authority’s Lower San Luis Rey River Valley Groundwater & Storage Feasibility Study. The study explored storing and pumping water from the lower San Luis Rey River Basin. The Mission Basin is one of five groundwater basins located within the San Luis Rey River Basin.
In 2003, the city of Oceanside and Water Authority agreed to study how to increase the yield of groundwater resources in the Mission Basin. As part of the agreement, the city of Oceanside agreed to reimburse the Water Authority for construction of three production wells. In total, eight production wells will be used to supply the desalter facility.
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