This project will begin implementation of fish passage designs completed in June 2017 (project 15-1324) by the Tri-State Steelheaders. In this phase, 880 feet of the concrete flood control channel will be remodeled to provide hydraulic conditions favorable for passage of adult and juvenile salmonids. Flood control measures on Mill Creek include a concrete channel that extends over two miles through Walla Walla. The Mill Creek Barrier Assessment completed in 2009 identified and described barriers for ESA listed steelhead and bull trout, and for reintroduced spring chinook. Returning adults encounter flow dependent depth and velocity barriers, and a lack of resting opportunities. Juvenile fish encounter low spring flows, and high water temperatures in late spring. Often by mid-May adults and juveniles become trapped in the flood control channel where they experience lethal temperatures. Many of these passage issues are considered as imminent threats in the Snake River Salmon Recovery Plan. Mill Creek, upstream of the flood control project, is a critical and under-utilized area for spawning and rearing of ESA listed species, and provides for an important recovery opportunity for those listed fish, as well as good habitat for other native fish and reintroduction efforts for spring Chinook.