Water

Refuge Water Supplies in the Central Valley

Ensuring reliable, affordable and accessible water supplies for wetland management may be the Central Valley Joint Venture's greatest challenge. When the Central Valley Project Improvement Act (CVPIA) was passed in 1992, it mandated the firm, reliable delivery of water supplies to 19 federal, state and private wildlife refuges in support of the objectives of the Joint Venture. The Central Valley Wetlands Water Supply Investigations, a report to Congress, focused on the adequacy of and needs for water supplies to existing private wetlands and the water supply and delivery requirements to permit full habitat development on supplemental wetlands. Much of this water is provided annually through long-term water contracts which the Bureau of Reclamation has with the refuge managing agencies and with the local water districts which convey water to each refuge. But meeting the total water amount mandated by CVPIA is also somewhat dependent upon acquiring surface supplies or groundwater from willing sellers, either through purchase or exchange. It is this acquired water that typically falls at least 50,000 acre-feet short of what is needed. Having all the mandated water available annually and throughout the year is critical for CVPIA refuge staffs to optimally manage their wildlife habitat and meet the habitat requirements of migratory birds and other wildlife.

The maps on this page delineate the property boundaries for each of the 19 refuges that fall under the auspices of the CVPIA, as well as the conveyance pathways that each refuge has for receiving water supply.

West Sac Valley

The three federal refuges located at West Sacramento Valley are serviced by the Glenn-Colusa Irrigation District, which receives its water supplies from Shasta Lake via the Sacramento River. Upgrades to Glenn-Colusa Irrigation District conveyance facilities since the implementation of CVPIA have enabled year-round delivery of water supplies needed to optimize habitat.

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East Sac Valley

Refuges at the East Sacramento Valley do not have a connection to a Reclamation Central Valley Project (CVP) facility and instead receive their water from Thermalito Afterbay which is fed by the Feather River. Gray Lodge WA (and a small portion of Sutter NWR) are serviced by water districts which have contract supplies with the State Water Project. Reclamation provides Gray Lodge CVPIA water indirectly through an exchange with the State Water Project. Both refuges require improvements to existing conveyance facilities in order to receive full refuge water supplies.

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Grassland Ecological Area

Most of the federal, state, and private wetlands in the Grassland Ecological Area receive water delivered from the Sacramento-San Joaquin Delta and San Luis Reservoir through the Delta-Mendota Canal. This then makes its way through the various water districts with conveyance facilities connected to it. Merced NWR surface water supply comes through mitigation requirements assigned to the Merced Irrigation District while San Luis NWR East Bear Creek Unit currently relies upon its water rights through Bear Creek, though potentially could receive water via the Eastside Bypass. Lack of affordable or adequate quality water supplies limit the optimal development of refuges in the Grassland Ecological Area.

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Mendota

Mendota WA receives its water supplies from Mendota Pool via Fresno Slough. Mendota Pool itself is fed through water delivered primarily from the Delta-Mendota Canal. When Mendota Pool is dewatered for maintenance of Mendota Dam, water is partially supplied through Westlands Water District. Capacity and operational issues of the existing conveyance facilities prevent delivery full refuge water supplies to Mendota WA.

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Kern/Pixley

Both Kern and Pixley do not have any connections with CVP facilities. Kern NWR receives exchanged water with the State Water Project via the California Aqueduct. Pixley NWR is dependent on groundwater wells for its entire supply. Limited conveyance options and sources of adequate water supplies are continual challenges for both refuges.

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It is hoped that these maps will provide several benefits: as a guide for a potential willing seller who has a surplus water supply, and who may be interested in assisting managed wetlands, but who may be unsure of where the nearest refuge may be located, or how their supply may physically get to that refuge. The maps can also complement a wetland-related presentation, or serve as a general educational tool for anyone interested in knowing where these 19 CVPIA refuges lie within the Central Valley and the proximity of one refuge to the other.