Restoring a Historic Creek Channel to Improve Fish Passage

Thurston County has a robust program dedicated to restoring fish passage habitat, with over 350 fish passage barriers identified throughout the county. When Country Club Road NW was built in the 1970s, a culvert was installed to keep Green Cove Creek flowing underneath it. The result was a 3-foot-wide culvert covered by 50 feet of rocks and soil with a road and utilities on top. During winter rains, the water flow through this culvert is too fast for most fish to swim against, preventing them from reaching upstream spawning grounds. Removing barriers in the creek will allow fish to move more effectively, supporting a healthier and more biodiverse ecosystem. The project will also improve road safety while maintaining connectivity and utility services.

The project to remove the barrier was in the planning stages for several years. However, due to the high cost, limited resources, and competing priorities, a permanent solution had not been found. In the fall of 2021, inspectors found the existing culvert had collapsed one foot since 2019. On November 10, 2021, Public Works completed an emergency repair to maintain streamflow, protect the public, preserve the roadway and utilities, and ensure emergency access for residents. During the repair process, crews reported that the culvert continued to deteriorate and collapsed further. Without this emergency work, the culvert likely would not have survived through the winter.

HDR was hired to assist the County replace the existing culvert with a bridge to improve a fish passage crossing. We developed final plans, specifications, and estimate for the County’s preferred alternative, which involved a new 150-foot permanent bridge. The project required removing a 50-foot mound of soil (20,000 cubic yards) to accommodate the bridge, the road is elevated above the creek. We also prepared 60%, 90%, and final bid-ready PS&E documents, including stormwater reports, bidding and construction support.

With a total cost of $9.1 million, the project will ultimately restore the creek’s natural flow, improving fish passage for species like chum salmon, coho salmon, rainbow trout, and coastal cutthroat trout.