Gosnell Creek LWD and Fish Passage - Phase 2

The Mason Conservation District will implement an in-stream restoration between stream mile 1.9 and 2.3 of Gosnell Creek, located S of W Cloquallum Rd and upstream of Isabella Lake in Mason Co. Gosnell Creek is the upper reach of the largest waterway in the Mill Creek watershed, one of the largest watersheds within WRIA 14. Gosnell Creeks cool temperatures and gravelly tributaries allow for Coho, Chum, and Steelhead to spawn and rear. Many of the natural processes in the Gosnell watershed are intact in its forested upper reaches, however agricultural practices and rural development have affected the lower mainstem network.

To preserve the current instream temperatures of Gosnell Creek and sustain a healthy spawning and rearing refuge, local strategies recommend implementing projects focusing on several strategies, including installing LWD in lower Gosnell Creek. The project will advance ongoing efforts to restore normative function for a high priority reach along the mainstem of Gosnell Creek through the installation of ten large wood habitat structures and construction of back-channel connecting to floodplain habitat. These changes will provide the necessary direct and indirect habitat for juvenile and adult salmonids and other aquatic species. Using funds from RCO #22-1180 (Phase 1), MCD will be restoring the flow regime for an onsite tributary making this phase 2. This removes a portion of the current project and lessens the proposal request.

The primary goal of this project is to restore and enhance habitat conditions for all life stages of Coho, Chum and Steelhead (as well as other secondary species) within the project reach through LWD placement to create additional pool habitat and spawning gravel beds.
The secondary goal for this project is to restore natural stream channel morphology and complexity diversity through placement of LWD to reduce summer water temperature and restore channel stability and natural channel pattern.