Hunter Point Road Culvert Replacement
The salmon returned to the Hunter Point Road culvert after 100 years away, thanks to the investment of Thurston County, Washington, in rehabilitating the culvert and the stream. The culvert was in a deep ravine and had a large drop at the downstream end, which blocked fish passage. Thurston County received state grants for culvert replacements, and Hunter Point Road was their highest-priority fish passage project. The project involved a new bridge and complete stream reconstruction, completed in fall 2018. Complications included high road embankments, a single access road (dead end), a stream confluence immediately upstream of the crossing, and the need to provide habitat function to the stream beneath the bridge structure. After consulting with the tribes and the Washington Department of Fish and Wildlife, the team elected to include large woody debris in a variety of configurations along with specific stream bed geometries and materials.
During construction, the County fish salvage team relocated approximately 500 fish from the downstream reach, indicating the high potential of future use upstream of the project. Otak structural engineers designed an 80-foot-span bridge to replace the existing four-foot-diameter culvert. Shortly after construction was complete, spawning salmon returned, after almost a century-long absence. This was a historic moment, and a tribute to the funding agencies and Thurston County for funding this project and hiring Otak to bring it to fruition.
Client: Thurston County
Date Completed: 2018
Project Manager: Doug Sarkkinen
Otak Team Contract Amount/Total Project Cost: $337,867; $263,962
Type: Transportation, water resources, construction management & inspection