Snoqualmie Large Wood Placement Concept Design

Wild Fish Conservancy will work with an environmental engineering firm to assess the feasibility of large wood (LWD) supplementation in the Snoqualmie River from its confluence with the Tolt River, downstream to Harris Creek near Chinook Bend Natural Area (RM 21-25). The assessment will lay the foundation for conceptual designs that will detail instream LWD treatments in the Chinook Bend -Tolt reach of the Snoqualmie River. Recent assessments of instream LWD as a function of adjacent riparian forests in the Pacific Northwest (Martens et al 2020) have shown that without mature riparian forests, many river reaches will not reach historic LWD loading without several hundred years time or LWD supplementation. The Chinook Bend -Tolt reach of the Snoqualmie River is an important reach for both spawning and rearing for Chinook salmon. For this reason the reach has been targeted for floodplain reconnection and restoration projects. Despite these efforts, LWD loading in the reach is low relative to historic levels.  Design considerations for the reach include boater safety, maximizing complex edge habitat in the reach, and structural stability in a large river environment. Conceptual Design deliverables will meet the requirements of Manual 18 Appendix D-1.

The goal of this project is to develop conceptual designs for instream LWD restoration treatments in the Chinook Bend -Tolt reach of the Snoqualmie River and satisfy community stakeholder concerns. If constructed, the designs will contribute to improved instream habitat conditions for salmonids in the project reach for the next 30-50 years.