Salmon need cold water to survive. Dams on the Columbia and Snake Rivers are making the water too hot, in some places by as much as 5 degrees.
Now, after a drawn-out lawsuit and direction from the state of Washington, the federal Environmental Protection Agency has released plan to change that.
Last week, the state Department of Ecology used its authority under the Clean Water Act to require the federal operators of eight dams on the lower Columbia and Snake rivers to keep the water at 68 degrees or lower. Right now, it’s routinely hitting 72 or 73 degrees in parts of the system, says Brett VandenHeuvel, executive director of Columbia Riverkeeper, which sued to get the plan.
“It's pretty simple math,” he said. “It's a long, complicated plan, but it looks at the temperature now with the dams in place. And then it uses computer modeling to show what the temperature would be if we remove the dams and have a free-flowing river and it assigns a needed temperature reduction to each dam.”
Glen Spain is with the Pacific Coast Federation of Fishermen’s Associations, a co-plaintiff in the lawsuit. He says the livelihood of thousands of fishermen on the West Coast depends on healthy salmon runs. And the Columbia system — one of the most important sources — has been impaired.
“The science is clear,” Span said. “If you want to have salmon in the river, you have to reduce the overall temperatures, particularly in the summer. We've had several disastrous die-offs because of high water temperatures in the basin. And that can only be worse under climate change scenarios, in a number of ways.”
But some critics question if dam removal is the best plan or if other fixes could work, such as adding shade plants or cooler water from upstream.
Washington state now must hold the Army Corps of Engineers accountable as that agency implements fixes to bring the water temperatures down. The rivers are an important source of fish for people and for Puget Sound’s endangered Southern Resident killer whales.
The EPA has posted the plan and supporting materials for public review. The agency is accepting public comments through July 21.