Changing Channels: Fish Screening, Passage and Restoration on Crabtree Creek

This project developed concepts to address a significant erosion and fish passage problem causing impacts to salmonid rearing habitat in Crabtree Creek, a large tributary of the South Santiam River that is designated critical habitat for federally listed Upper Willamette Spring Chinook salmon and steelhead. It is also home to other locally important species, such as cutthroat trout and Pacific Lamprey. This reach of Crabtree Creek has experienced significant changes in channel morphology and location, due in part to land use practices that have resulted in a simplified channel and reduced riparian function. Lateral channel migration has resulted in active and extensive streambank erosion. This has a deleterious effect on aquatic habitat and water quality, makes operation and maintenance of the unscreened Gaines Irrigation District’s headgate problematic, and is threatening to undermine a key county road. This project evaluated current conditions, collected environmental and geomorphological data, created a complete hydrologic model of the stream reach in question, calculated likely scenarios at various flood stages, and developed conceptual plans for local landowners and partners to review. The South Santiam Watershed Council and contract design firm held a community meeting to share conceptual plans and coordinated with ODFWs screens and passage staff and irrigation district water master to ensure that instream work, habitat work, and new irrigation headgate and fish screen installation could be conducted simultaneously. The project encountered several roadblocks that precluded us from achieving the full suite of work, such as parcel land ownership change and one party withdrawing support. Final project design, permitting and implementation for the conceptual designs will be completed in a future project.

Taken on its own, this technical assistance project will lay the groundwork for restoration to occur. This initial round of work is critical to help ensure that subsequent on-the-ground restoration would provide benefit to salmon and steelhead habitat in Crabtree Creek. The survey and design work proposed in the TA will help us understand the current conditions, and the factors that have lead to the challenges described above. This will allow the stakeholder group to work with the contractor to develop projects that are designed to address the specific conditions and limiting factors identified in this reach. Restoration projects guided by this site-specific data and recommendations from the Upper Willamette River (UWR) Conservation and Recovery Plan for Chinook Salmon and Steelhead will result in improved and expanded habitat for Upper Willamette River Chinook Salmon and steelhead, and other native species. Given the pressures of climate change and decreasing run sizes, restoration work that adequately addresses water quality, water quantity and instream habitat is urgent.