Water Supply and Sources
The City’s current water supply consists of imported surface water from the Calleguas Municipal Water District (CMWD), groundwater from the United Water Conservation District (UWCD), and local groundwater from City wells. The City blends water from these three sources to achieve a balance between water quality, quantity and cost.
Imported State Water
To provide for long-range improvement of its water quality, the City annexed to Calleguas Municipal Water District in February 1961. CMWD is a member agency of the Metropolitan Water District of Southern California (MWDSC) from which it purchases State Project Water. Therefore, as a sub-agency under CMWD, Oxnard water customers can participate in water conservation incentive programs offered by MWDSC, such as bewaterwise.com.
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.
United Water Conservation District 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.
During high flows, 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 Plain. 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 basins. 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).
Groundwater is directly pumped from seven wells and then disinfected with chlorine and mixed (blended) with imported water at a blending station. In addition, groundwater with high-salt content, which would otherwise be unusable for drinking water, has been cleaned by Oxnard’s Desalter facility since 2008. The Desalter utilizes reverse osmosis treatment to remove most of the dissolved minerals and salts from the water and can produce up to 7.5 million gallons per day. This low-mineral water is then blended with Oxnard’s other sources to maintain a consistent water quality (less hardness) and to keep the water’s taste more aesthetically pleasing.
The Fox Canyon Groundwater Management Agency (FCGMA) 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 FCGMA 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 FCGMA 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.
Especially during drought cycles, the FCGMA has over the years reduced the allowable amount of pumping by groundwater users to manage groundwater extractions from the Oxnard Plain aquifers. This authority became more defined in 2015 through the Sustainable Groundwater Management Act (SGMA). SGMA requires each California groundwater basin to establish a Groundwater Sustainability Agency (GSA) and FCGMA assumed the new responsibilities as the GSA for the basins within their jurisdiction.
To guide the path to sustainability, FCGMA adopted Groundwater Sustainability Plans (GSPs) in 2019, covering Oxnard and Pleasant Valley Basins. The GSPs describe the sustainability goals, explain how and what actions will be needed to achieve the goal in 20 years, and include a 50-year planning and implementation horizon, as well as a monitoring program. In 2021, the California Department of Water Resources (DWR) approved the GSPs.
Report water waste and leaks online at 311.OXNARD.ORG
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