Fish habitat provided through removal of fish passage barriers in the Cedar River Municipal Watershed

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Seattle has increased the spawning and rearing habitat available to fish through the removal of barriers that once blocked fish from moving upstream. Decades ago, when many of the roads in the watershed were constructed, streams were put in culverts that fish could not pass through. Fish could not pass through the culverts due to high water velocities, shallow depth of the water in the culvert, debris getting stuck in the culverts, and erosion that made it impossible for the fish to enter the downstream end of a culvert (perched culverts).

As part of the Cedar River HCP, Seattle has been removing these barriers in the watershed. We have been replacing culverts that were barriers with bridges, and with culverts that are fish friendly. A fish friendly culvert is a culvert that allows fish to enter and easily move upstream. These culverts are usually larger than the size of a culvert designed just to pass water. They are often open on the bottom, and more oval than round. The graph shows the increases in the linear distance of streams that have been made available to fish above previously impassible barriers.

 

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