Willamette River Stormwater Outfall Stabilization

W2r addressed erosion issues at multiple outfalls along the Willamette River in Wilsonville, Oregon

Wolf Water Resources (W2r) worked with a team of civil and geotechnical consultants to address channel erosion at stormwater outfalls to the Willamette River. This complex project benefitted integration of natural channel design and traditional civil engineering strategies. Specifically, designs focused on channel stabilization via step pools and rock lined chutes in erosion prone reaches with recommendations for vegetation enhancements along the Willamette River and lower gradient reaches. W2r approached the design alternatives with an understanding of what the regulatory agencies would require and what could be covered under various programmatic permitting tools. This saved considerable time and money in developing design iterations and the alternatives assessment. Further, our in-depth hydraulic analysis addressed the implications of potential permitting requirements such as the use of rounded rock or large wood within weak soils along a large river. This facilitated negotiation of a design that minimized impact to habitat and water quality while stabilizing and enhancing eroded channels.