DESCRIPTION
The upper Deschutes (RM 31041) is high priority for rearing, spawning and egg incubation yet the reach lacks LWD, habitat complexity (pools) & stability. The Coho Recovery Report modeled a 7% decrease in fine sediment and 25% increase in LWD (Scenario A) to have the second largest impact on Coho survival; the first being increased marine survival. Specifically identified is treatment of the area between Fall creek (RM 35) and Pipeline creek (rm 31) to reduce fine sediment input that reduces egg to emergence survival.
The RM 33 Instream Channel Complexity & Riparian Planting project addressed the above limiting factors by adding stable large wood (pieces & structures) for pool formation, gravel bar formation, increased retention and decreased summer channel width to increase water depth. Project goals also include increasing riparian vegetation for long-term sediment reduction and stream shading.
This site was identified through the WRIA 13 three-year implementation priority list, watershed outreach and inquiries from the former landowner. Lack of LWD is a limiting factor for the Deschutes River as is an excess of fine sediment, lack of riparian cover and temperature. This project addresses all of these. This project seeks to restore the aquatic habitats on approximately 1,500 linear feet of river channel in the reach by increasing the amount of large woody debris, re-establishing native riparian forest and creating in-stream complexity. A conceptual design, funded with a g
The Deschutes RM 33 LWD Design grant developed preliminary designs that identified appropriate habitat structures and probable project costs at River Mile 33 on the Deschutes River. This project built upon a conceptual level investigation completed on 2014 with limited funding from the Squaxin Tribe. The design process conducted additional geotechnical investigation and hydraulic modeling for a 1,500 linear foot reach. The Design Team, comprised of representatives from Weyerhaeuser, the Squaxin Tribe's Natural Resources Department, the Department of Fish and Wildlife and the Lead Entity Committee, selected a preferred alternative designed to enhance aquatic habitat in the reach by increasing the amount of large woody debris (LWD) resulting in adding channel and bank roughness to replace that lost due to loss of riparian habitat.
In 2015, the WDOE completed a total maximum daily load (TMDL) study of the Deschutes River watershed above Capitol Lake. A TMDL study describes maximum pollutant loads that a water body can receive while still meeting the water quality requirements of the federal Clean Water Act. The TMDL Implementation Actions (Table 23), lists this reach as a priority area for enhanced channel complexity including large woody debris within the active river bed to reduce fine sediment transport and provide pool formation. Annual fine-grained sediment production from the bank adjacent to Road 1120 is estimated to produce about 4.5 percent of the total fine-grained sediment for the entire watershed, and the Project reach is one of only five reaches of the Deschutes River that has received a target TMDL for fine sediment reduction.
