Rasmussan Creek at SR 112

Technical Description:

• Span: 16 ft
• Rise: 8 ft
• Length: 40 ft

Washington State’s wild salmon and trout habitats were being addressed through an ambitious program to remove fish passage barriers along state highways. Teams from the Washington State Department of Transportation and the Washington Department of Fish and Wildlife worked together to identify, prioritize and remove barriers in culverts under state roads. Since 1991, they’ve come up with 4,463 sites where state highways cross fish-bearing streams, and have identified more than 500 “problem culverts” where the water depth is too shallow, the water velocity too high or the outfall drop too far. Engineers have begun fixing the culvert barriers using a “Priority Index System” that ranks projects according to their potential habitat gains.

For years, fish could not swim through the fast-moving waters in some Rasmussan Creek culverts. Two round culverts under State Route 112 had been built on a steep slope, so the water velocity was too high for most fish swimming upstream. Engineers replaced the culverts with a CON/SPAN^® single concrete archway spanning the stream that was ideal “natural” conditions for fish passage. The project added nearly 7/8 of a mile (1,324 m) of stream habitat, and post-project surveys reported coho salmon, cutthroat trout and other fish species in the upstream section of the creek where they had not been seen before.

Technical Description:

• Span: 16 ft
• Rise: 8 ft
• Length: 40 ft