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 Endangered Species Act (ESA) listed steelhead and bull trout and for reintroduced spring Chinook in the flood control channel. 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 imminent threats in the Snake River Salmon Recovery Plan. The Mill Creek channel upstream of the flood control project is a critical and under-utilized area for spawning and rearing of ESA-listed species. Restoring fish passage to upper Mill Creek provides an important recovery opportunity for ESA-listed fish, as well as good habitat for other native fish and reintroduced spring Chinook. Designs for remodeling the concrete channel to improve water velocities and depths have been implemented and tested in multiple previous construction projects. This project will complete final designs specific to the Colville to 3rd Ave portion of the concrete channel. This project is one of multiple projects that are necessary to correct fish passage problems in the Mill Creek flood control project.