Couse Creek at Blue Mountain Station Fish Passage

Removal of a concrete irrigation dam functioning as a fish passage barrier was successfully accomplished to open suitable salmonid habitat upstream. Channel structure features were added to improve stream habitat diversity by placing whole trees with root wads, boulders, and logs. Streambank stabilization was incorrectly reported at project proposal, as the activities done are best descriped under channel structure placement. Invasive species removal and multiple tree planting efforts with native willow and cottonwood species were conducted, and supplemental tree plantings were conducted to achieve optimal survival. This vegetation will provide much needed shading to an exposed creek system which has intermittent, seasonal base flows and water temperatures approaching levels of intolerance regarding salmonid inhabitance.

The WWBWC is following hierarchical strategies for prioritizing restoration actions in Pacific Northwest Watersheds as outlined by prominent Pacific Northwest authors Phil Roni and Tim Beechie in various guidance papers. More specifically, we are focusing on reconnecting isolated high-quality fish habitat made inaccessible by obstructions, which is recommended before methods that produce less consistent results. Various published scientific literature shows that reconnecting habitats provides a potent return on investment in the form of quick biological response, high likelihood to succeed, and last many decades. Following passage rectification, WWBWC is progressing into Phase 3--implementing Beaver Dam Analogs and PALS structures over multiple years in the middle to upstream reaches. WWBWC Aquatic Habitat Inventory results determined that 53% of the creek was classified as perennial and 47% was intermittent, typical of a classic steelhead centric system. The majority of suitable, wetted habitat units are located upstream from the impediment at RM 3 as the entire section downstream goes subsurface annually. Within the perennial reaches approaching the headwaters exists habitat values that rank as moderate to high and provide year round suitability to life stages of salmonid inhabitance. Couse Creek provides approximately 20% of the documented redd counts on an annual basis. Adults spawn in the lower reaches that eventually go dry, but evolutionary adaptation triggers offspring to seek perennial reaches in the headwaters and adjacent mainstem Walla Walla river. Upon rectifying the final passage impediment at RM 3, fishes should have free will movement to advantageous habitats and ultimately contribute to biological response to positive changes in physical habitat features as result of restoration actions.