Grouse Creek Assessment

Located in northern Idaho, Grouse Creek is a primary tributary to the Pack River in the Lake Pend Oreille watershed. Grouse Creek supports important spawning and rearing habitats for native fish species including bull trout and westslope cutthroat trout, as well as sought after game fish including Kamloops rainbow trout. Historical land uses, primarily logging, impacted the watershed by increasing sediment and water delivery to the channel network, removing large riparian trees, and clearing land. Combined with the legacy effects from high intensity wildfires throughout the watershed, Grouse Creek was identified as water quality-limited by the State of Idaho and is listed on the State of Idaho’s 303(d) List of Impaired Waterbodies due to excess solar loading and sedimentation.

In 2007, Avista Corporation, in coordination with state and federal agencies and the Grouse Creek Technical Committee, retained RDG to conduct a watershed assessment and restoration prioritization plan for Grouse Creek. The work included completing geomorphic and aquatic habitat surveys on the mainstem Grouse Creek and primary tributaries, evaluating all stream crossings in the watershed to prioritize fish passage improvement opportunities, evaluating and mapping all major sources of sediment including streambank erosion and hillslope mass wasting, and evaluating riparian conditions including solar shading.

Since adoption of the watershed assessment and restoration prioritization plan, several projects have been implemented in the lower reaches of the watershed. Projects have focused on restoring streambank conditions that provide increased stability and resilience to flooding. A variety of bioengineering techniques have been utilized including single and double layer encapsulated soil lifts, and vegetated wood and brush fascines. Post project monitoring has demonstrated a significant reduction in sediment loading to lower Grouse Creek. RDG is continuing to coordinate additional restoration work with resource agencies and landowners.