Department of Water Resources Home
Cliff Feldheim, Chief
Environmental Planning and Information Branch
Suisun Marsh Program
3500 Industrial Blvd.
West Sacramento, CA 95691
(916) 376-9693
Mailing Address:
P.O. Box 942836
Sacramento, CA 94236-0001

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The Suisun Marsh

The Suisun Marsh is the largest contiguous brackish marsh remaining on the west coast of North America. It is a critical part of the San Francisco Bay-Delta estuary ecosystem. Encompassing 116,000 acres, the Suisun Marsh includes 52,000 acres of managed wetlands, 30,000 acres of bays and sloughs, 27,700 acres of uplands, and 6,300 acres of tidal wetlands. It is home to public waterfowl hunting areas and 158 private duck hunting clubs. The Suisun Marsh serves as the resting and feeding ground for tens of thousands of wintering and migrating waterfowl and provides habitat for more than 221 species of birds.  The Suisun Marsh supports more than 40 species of fish and 80% of the state's commercial salmon fishery by providing important tidal rearing areas for juvenile fish allowing them to grow twice as fast as those reared in the upper watershed (improving their survival).  The Marsh is also home to the endemic Tule Elk, and Federally Endangered Salt Marsh Harvest Mouse.  The Marsh's large open space and proximity to vast urban areas makes it ideally suited for wildlife viewing, hiking, canoeing, and other recreation opportunities.

Because of the need to mitigate for water quality impacts (i.e., increased salinity) in the Suisun Marsh resulting from the Central Valley Project, State Water Project, and other upstream diversions, in March 1987, DWR, the Department of Fish and Game (now California Department of Fish and Wildlife), the U.S. Bureau of Reclamation (USBR), and the Suisun Resource Conservation District signed the Suisun Marsh Preservation Agreement (SMPA). The objectives of the SMPA include:

  • To assure that USBR and DWR maintain a water supply of adequate quantity and quality for managed wetlands within the Marsh.

  • To improve managed wetland habitat.

To aid in improving water quality for managed wetlands, several facilities have been constructed by DWR and USBR within the Suisun Marsh.  These facilities include the Roaring River Distribution System, Morrow Island Distribution System, and Goodyear Slough Outfall (constructed in 1979 and 1980). The Suisun Marsh Salinity Control Gates were installed and became operational in 1988.  DWR also has 16 water quality monitoring stations spread throughout the Marsh.  Suisun Marsh salinity standards have been established to evaluate water quality.  The salinity standards were determined based on the need to provide high quality foraging habitat for wintering waterfowl using managed wetlands.

In 2014, The USBR and U.S. Fish and Wildlife Service, in partnership with the California Department of Fish and Wildlife (formerly the Department of Fish and Game) and DWR finalized the Suisun Marsh Habitat Management, Preservation, and Restoration Plan EIS/EIR. The goal of the plan is to achieve an acceptable multi-stakeholder approach to the restoration of tidal wetlands and the enhancement of managed wetlands (as a means of offsetting the impacts of tidal restoration on waterfowl). The Plan calls for 5,000 to 7,000 acres of tidal restoration and 40,000 to 50,000 acres of managed wetland enhancement to benefit wintering and breeding waterfowl.

The Final EIS/EIR is available online at US Department of the Interior.

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Suisun Marsh is located in southern Solano County, California about 35 miles northeast of San Francisco. The marsh is bordered on the east by the Sacramento-San Joaquin Delta, on the south by Suisun Bay, on the west by highway 680, and on the north by highway 12 and the cities of Suisun and Fairfield.
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