Image above depicts major project features. See design report for additional details. Credit ESA (2011); USDA-NAIP (2009).
Spencer Island is located in the Snohomish River estuary between Union and Steamboat Sloughs near Everett, Washington. Historically, diking and drainage for grazing at this site led to the loss of tidally influenced wetlands and distributary channels, though portions of the levee system have failed over time and the site has not been suitable for agriculture for over 15 years. Despite past breaches in the levee that partially restored tidal processes to the project area, man-made features that no longer serve a purpose including remnant levees and field drainage channels prevent the island from reaching its full habitat restoration potential. This restoration project will lower and breach levees, restoring full estuarine processes and seasonal riverine flooding. These restoration actions will re-establish conditions necessary to improve 313 acres of rare tidal freshwater marsh.
Snohomish County and Washington Department of Fish and Wildlife (WDFW) manage the site as a popular park and wildlife management area and will include recreational uses in the habitat restoration plan.
Key Design Elements
Expand two existing levee breaches and add a third, allowing more tidal flow to enter the island interior
Lower and plant existing Steamboat and Union Slough levees to create a riparian woodland corridor that mimics a natural condition that would be found on an unaltered island
Maintain access to the existing public trail system
WDFW is currently having internal discussions in anticipation of a future restoration project. Community outreach and engagement will be a part of any future project planning.
Ecosystem Restoration Benefits
Restore large river delta that provides valuable nursery habitat for juvenile threatened salmon species, increasing survival and supporting Puget Sound population recovery
Restore highly productive tidal freshwater wetland habitats that support a diverse array of species and provide connectivity between land and sea
Contribute to improved estuary water quality
Improve public access to shore and recreational opportunities
The importance of this project
Enhances previous restoration work and complements other nearby slough system restoration activities
Contributes to salmon recovery consistent with the Federal Puget Sound Chinook Recovery Plan
Restored wetland area provides waterfowl habitat and filtration of pollutants