Flood control measures on Mill Creek include a concrete flood control channel that extends over two miles through the city of Walla Walla. The 2009 Mill Creek Barrier Assessment identified and described barriers in the flood control channel for Endangered Species Act (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 imminent threats in the Snake River Salmon Recovery Plan. The 5th Avenue bridge has a support pier in the channel which creates even worse hydraulic conditions for passage than elsewhere in the channel. It also takes up space in the channel, which means that the passage treatment, and access for county maintenance vehicles cannot all fit. The sponsor proposed removal of the 5th Avenue Bridge and replace it with a pedestrian bridge that does not require footings in the channel. By doing so, the installation of the Mill Creek passage treatment panels and maintenance vehicle access become possible at this location.