Corps uses deeper water to cool fish ladders, improves salmon pa - NBC Right Now/KNDO/KNDU Tri-Cities, Yakima, WA |

Corps uses deeper water to cool fish ladders, improves salmon passage

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WALLA WALLA, WA - The Walla Walla District of the U.S. Army Corps of Engineers continues to improve adult salmon passage on the lower Snake River to counter the effects of hot summer water on migrating adult salmon and steelhead.

Adult sockeye salmon are especially susceptible to high water temperatures due to the timing of their upstream migration. "Thermal barriers" of hotter water can impair their migration. Corps salmon managers cool river water in various ways to help fish survive and migrate.

At Little Goose Lock and Dam, the Corps is using a temporary pumping system this summer to capture cool water from about 60 feet down in the reservoir on the upstream side of the dam and pump it into the fish ladder exit, or upper end of the ladder.

"We're applying lessons learned upstream at Lower Granite," said Roger Golladay, operations project manager at Little Goose. "We're using a system here this year similar to what Lower Granite used in 2014 and 2015 to cool their adult fish ladder."

At Lower Granite, the Corps completed installation in February 2016 of the Adult Fish Ladder Temperature Improvement System. The system is working well. The Corps is seeing fewer adult salmon fall back downstream as they did in the past when encountering thermal barriers in the fish ladder.