WALLA WALLA, Wash. – On May 3, the U.S. Army Corps of Engineers, Walla Walla District awarded a $5.6 million construction contract to Advancia Remediation Services, LLC to improve habitat conditions for endangered salmonids in the Mill Creek channel.
This project, funded by the Bipartisan Infrastructure Law, will modify 40 of the existing weirs within the federally owned and operated portion of the Mill Creek flood control channel, immediately downstream from the diversion dam.
The modified weirs will create flow velocities that will assist outmigration of juvenile salmonids and provide attraction flow for adults returning to spawning habitat upstream. These modifications will improve fish passage conditions for two fish species, mid-Columbia Steelhead and Bull Trout, listed as endangered or threatened under the Endangered Species Act (ESA). It will also benefit Spring Chinook salmon reintroduced under a program managed by the Confederated Tribes of the Umatilla Indian Reservation (CTUIR).
Construction will take place between June 15 and Oct. 31 of 2024 and 2025, during the in-water work window, in compliance with ESA requirements of the U.S. Fish and Wildlife Service and National Marine Fisheries Service biological opinions. The remaining 40 weirs in the federal portion of the channel are planned to be modified at a later date.
This project will build on a network of projects already completed by USACE, the CTUIR, the Walla Walla 2050 Watershed Planning Partnership group, and the Tri-State Steelheaders, to improve fish passage in Mill Creek and provide connectivity and passage to high quality spawning habitat upstream of the Mill Creek flood control project.
Release no. 24-027