CTUIR, Corps of Engineers sign pact to improve Mill Creek fish passage

WALLA WALLA — Officials from the Confederated Tribes of the Umatilla Indian Reservation and U.S. Army Corps of Engineers held a signing Jan. 10 at the Corps’ Walla Walla District headquarters to honor a joint project to improve fish passage on Mill Creek, according to an announcement from the CTUIR. 

The project will remove 7 miles of flood control structures the Corps installed in the creek from 1939 to 1943 to protect the city of Walla Walla, according to the announcement. Those structures consisted of stream channelization with levees, 250 cross-channel small dams and a concrete channel through downtown Walla Walla.

“Over many years, flood control was the driving force of river management without consideration of the impacts to the natural environment. Public safety and human health are two key goals of the Corps of Engineers, but so is environmental protection and enhancement,” CTUIR Chairman Gary I. Burke wrote in the announcement. “The CTUIR has worked with the Corps and other partners to ensure that environmental management and flood control can co-exist. We hope that this project, and others like it in the Walla Walla and Columbia basins will address the damage to fish habitat and passage we’ve seen over the last century understanding that this is a long-term process and continued restoration efforts will be needed in the Walla Walla Basin. It will continue to be important for projects such as this to be carried out to restore and protect the resources important to the exercise of CTUIR treaty rights.” 

Burke added that it was fitting the ceremonial signing took place on Jan. 10, as it was the five-year anniversary of the groundbreaking of the CTUIR’s South Fork Walla Walla Fish Hatchery. 

Jerimiah Bonifer, CTUIR Department of Natural Resources Fisheries Program manager, wrote that the project is a significant step in improving fish passage in the Walla Walla Basin, which has suffered similar problems as the Umatilla Basin has such as over-appropriation of water and degraded habitat. 

“The Walla Walla Basin has excellent habitat in the headwaters; however, agricultural, industrial and residential development in the lower basin has severely degraded fish passage for salmon to the headwaters. This project is aimed at improving passage to give salmon populations the potential to flourish after decades of declines,” Bonifer wrote. 

Because the Corps transferred the structures decades ago to Walla Walla County, the Corps requires approval from the county and specific sponsors of projects for federal funding, limiting its ability to fix problems the flood control construction created, according to the announcement. However, the CTUIR and Corps have worked to expand this authority. In 2023, the CTUIR proposed a pilot project under the Water Resources Development Act of 2020, requesting up to $10 million in federal funds to notch 63 grade control sills along eight-tenths of a mile on Mill Creek. The Corps approved the plan on Aug. 29, 2024. 

Mike Lambert, DNR Fisheries Habitat Program supervisor, wrote in the announcement that the notching entails constructing a river low-flow channel within each sill so juvenile and adult fish can move within the flood control channel. 

“Mill Creek supports populations of … summer steelhead and bull trout, as well as reintroduced spring Chinook salmon and other culturally important First Foods fish species,” Lambert wrote. “These fish transit the Mill Creek Flood Control Project on their upstream migration to spawning habitat in the headwaters of Mill Creek and on their downstream migration to the Pacific Ocean and mainstem Columbia River habitats.”

Although ceremonial, the signing showcases the CTUIR’s cooperative efforts with the Corps to safeguard resources guaranteed under the Treaty of 1855 while protecting Walla Walla’s people and property, the CTUIR wrote in the announcement. 

“Today’s signing is a milestone in our collaboration as we formalize our commitment to improving fish passage along Mill Creek,” Walla Walla District Commander Lt. Col. Kathryn Werback wrote in the announcement. “This partnership emphasizes the best of what we can achieve when we come together with a shared purpose. Mill Creek is home to several ESA- (Endangered Species Act) listed species and other species that represent more than just biodiversity, which we hope will thrive for generations to come.”