PACE provided stream design for two fish-passable water crossings on SR 20 tributaries to the Skagit River, addressing steep slopes and significant scour risks. One channel, with a 10% slope, stands as one of the steepest stream crossings built in the region. The deep fill and large retaining walls at the site posed additional challenges, increasing vulnerability to scouring. To counter these issues, PACE used various channel complexity features—such as strategically placed large woody material—to enhance vertical stability, prevent erosion, and maintain natural stream function. These solutions ensure long-term durability while improving fish passage.
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