A federally authorized levee and multiple flood control structures will be removed/modified in order to reconnect over 1,000 acres of floodplain at the Steigerwald Lake National Wildlife Refuge. Located along the Columbia River near Washougal, Washington, the project’s sponsors include the Lower Columbia Estuary Partnership and the Port of Camas-Washougal. As the prime consultant, Wolf Water Resources (W2r) is leading a large team in the design of this floodplain restoration.
Project progress in all phases of this project has been greatly dependent on the coordination with numerous stakeholders including USACE, WSDOT, Port of Camas-Washougal, City of Washougal, USFWS, BPA, USACE, Friends of the Columbia Gorge, Burlington Northern Santa Fe Railroad, and several private landowners. W2r team members were directly involved in the landowner coordination, including face-to-face meetings. Coordination with landowners resulted in adaptive design solutions so that restoration and flood reduction features could meet multiple objectives.
The permitting phase of the project is complete and the final design is nearing completion in April 2019. Key permitting and design aspects involved:
- Meeting Section 408 requirements.
- Compliance with HIP III Section 7 for a High Risk project requiring variances.
- Design for improved outlet conditions for the Gibbons Creek confluence with the Columbia River.
- Maintaining the long-term stability of the bridge across Gibbons Creek on State Highway 14.
- Sediment transport modeling and analysis ensured functioning stream habitat and adequate gravel transport processes over the long term (50-year model demonstrated channel resilience to variable long term flow and sediment inputs).
- Design to encourage beaver establishment and fish passage.
- Floodplain/wetland/riparian plantings based on historical communities.