Trade-Offs between On-Site and Watershed Restoration Goals in Dam Removal: Goldsborough Creek Dam Removal Project, Washington

The Goldsborough Creek Dam Removal and Stream Restoration Project is located in Mason County, Washington and was authorized under Section 206 of the Corps' Continuing Authorities Program. The project, which was initiated by Seattle District Corps of Engineers in cooperation with local sponsors, removed a deteriorated dam structure that was a hindrance to fish passage along Goldsborough Creek. Upstream of the project, the creek flows freely through forested areas and includes 14 river miles draining 51 square miles of high-quality habitat. The restoration objective was to remove the dam and allow for unhindered upstream and downstream passage of resident and migratory fish. A project was formulated that resulted in a highly structural approach to post-dam removal channel stabilization but resulted in a high level of certainty in limiting potential undesirable channel response and adverse sediment related impacts. The trade-off associated with the level of restoration of the area disturbed by the footprint of the Goldsborough Creek Dam and pool versus the avoidance of potential adverse impacts on stream stability and sediment transport processes are discussed. This trade-off is evaluated in the context of large-scale watershed benefits of restoring connectivity through the former project site.