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SELECTED PROJECTS: Snohomish County, Washington

Pilchuck Dam Removal Feasibility Study

Landau Associates provided fisheries resources and fisheries habitat survey services as a subconsultant in support of a feasibility study and preliminary design for the removal of the existing Pilchuck River dam and fish passage facility. The Pilchuck Dam provides a municipal diversion of water from the Pilchuck River to the City of Snohomish.

Recent listings of Puget Sound Chinook salmon and steelhead as threatened species have raised awareness of the importance of effective fish passage through Puget Sound tributary streams. Focused attention has been given to the Snohomish River system and its tributaries, which include the Pilchuck River, with efforts to eliminate critical fish passage barriers between the Puget Sound and upland headwaters. The Pilchuck Dam was identified as a high priority passage barrier, and the feasibility study and subsequent recommendations provide a preferred design to address fisheries, hydraulic, and geomorphologic issues associated with removing or replacing the diversion dam. Landau Associates provided biological design criteria for engineering design alternatives, identified and compiled potential funding sources for the City of Snohomish to offset the cost for project design completion and construction, and completed a snorkel survey for salmonids in the project area.