Water Supply and Sources
The City’s current water supply consists of imported surface water from the Calleguas Municipal Water District (CMWD), imported groundwater from the United Water Conservation District (UWCD), and local groundwater from City wells. Groundwater from City wells and from UWCD, comprises the greatest portion of the City’s water supply. The City blends water from these three sources to achieve an appropriate balance between water quality, quantity, and cost.
To provide for long-range improvement of its water quality, the City annexed to CMWD in February of 1961. CMWD is a member agency of the Metropolitan Water District of Southern California (MWDSC) from which it purchases State Project Water. Imported water supply originates in Northern California and is conveyed over 500 miles to Southern California through the State Water Project’s (SWP) system of reservoirs, aqueducts and pump stations. Water is filtered and disinfected at MWDSC’s Joseph Jensen Filtration Facility in Granada Hills. CMWD receives the treated water from MWDSC via the MWD West Valley Feeder and either stores the treated water in Lake Bard to be treated later or feeds the water directly to the Springville Reservoir near Camarillo. The City receives water from Springville Reservoir through the City’s Oxnard and Del Norte Conduits which feed the City’s four water blending stations.
UWCD currently provides a portion of the City’s groundwater supply. This arrangement has been in operation since 1954, and was formalized in the 1996 Water Supply Agreement for Delivery of Water through the Oxnard/Hueneme (O-H) Pipeline. UWCD holds a pumping sub-allocation for all users of the O-H Pipeline, which includes the City, the Port Hueneme Water Agency, and a number of small mutual water companies.
UWCD diverts water from the Santa Clara River at the Vern Freemen Diversion Dam southeast of Saticoy and delivers a portion of the water to the Saticoy and El Rio Spreading Grounds and surface deliveries to agricultural users on the Oxnard Plan. Water percolated in these spreading basins recharges the Forebay to the Oxnard Plain. Eleven wells are then used to extract the water and deliver it to the O-H users. The El Rio Pumping Station provides pressurized chlorinated groundwater directly through Oxnard-Hueneme (O-H) Pipeline along Rose Avenue to Oxnard’s five blending stations.
Local groundwater is generally extracted from the aquifers of the Oxnard Plain Groundwater Basin. The Oxnard Plain Groundwater Basin is made up of two aquifer systems known as the Upper Aquifer System (UAS) and the Lower Aquifer System (LAS).
The City currently has seven active wells and three wells under construction at Blending Station No. 1. The local groundwater is disinfected with chlorine and mixed (blended) with the imported water at the blending stations.
Fox Canyon Groundwater Management Agency
The Fox Canyon Groundwater Management Agency (GMA) was created in 1982 at the direction of the State Water Resources Control Board to address ongoing overdraft and seawater intrusion into the Oxnard Plain Pressure Basin. The purpose of the GMA is to manage the region’s groundwater supply by protecting the quantity and quality of local groundwater resources, and by balancing the supply and demand for groundwater resources. The GMA has jurisdiction over groundwater pumping for all of the land which overlies the Fox Canyon Aquifer. This encompasses approximately 185 square miles and includes the Oxnard Plain Forebay and the Oxnard Plain Pressure Basins underlying most of the City of Oxnard.
To manage groundwater extractions from the Oxnard Plain aquifers, the GMA has been implementing staged reductions in the allowable amount of pumping by groundwater users, including the United Water Conservation District and Oxnard. To date, reductions of fifteen percent (15%) from 1985-1989 pumping levels have been implemented and two additional five percent (5%) reductions are scheduled for 2008 and 2010. Even with these reductions of groundwater extractions, localized problems, including severely depressed groundwater levels in the Pleasant Valley area, remain to be addressed. Imported water deliveries are also approaching the limits of the Calleguas Municipal Water District’s delivery system, and costly capacity expansions will be necessary.