Four conservation and fishing groups plan a lawsuit over high water temperatures in the Snake River, calling for actions that could include removing the four lower Snake River dams in Eastern Washington.
Columbia Riverkeeper, Idaho Rivers United, Idaho Conservation League and the Northwest Sportfishing Industry Association formally notified the Army Corps of Engineers on Friday that it could file the lawsuit in 60 days.
Warm water in the lower Snake River is killing and injuring sockeye salmon, which are at high risk of extinction, said the notice to the Corps.
It said the four lower Snake River hydroelectric dams from Ice Harbor Dam near the Tri-Cities upriver to Lower Granite Dam near Lewiston, Idaho, are primarily responsible for the high water temperatures.
Without the four dams, the lower Snake River would remain cool enough to allow most sockeye salmon to migrate safely, even in very hot years, the legal notice said.
“Hot water in the lower Snake River has been a year-in, year-out problem for endangered salmon,” said Nic Nelson, executive director of Idaho Rivers United.
“Despite above-average snowpacks and a colder spring, we still have significant hot water pollution threatening these endangered fish,” he said. “The only way to save these runs are substantive changes to the system of operations on the Columbia-Snake River systems.”
Warm river water encourages the growth of disease-causing bacteria and fungi, delays migration and depletes the energy reserves of migrating fish, according to a Columbia Riverkeeper report on the dams and water temperatures, particularly in the hot summer of 2015.
Adult salmon have difficulty migrating upstream when water temperatures approach 68 degrees, and they stop heading upstream when water temperatures hit 72 to 73 degrees, the report said.
The lower Snake River water in summer 2015 was hotter than 68 degrees for two months. The Environmental Protection Agency concluded that roughly 250,000 adult sockeye salmon returning to the Snake or to upper Columbia tributaries died because of warm water, the report said.
The legal notice to the Corps put the 2015 adult Snake River survival rates at 4%, by far the worst in the decade.
Last year, the estimated survival rate was 66%, which met the survival rate of 65% that year as mandated under the Endangered Species Act, according to information in the legal notice to the Corps.
“It’s ironic that anti-dam groups are announcing this lawsuit in the name of sockeye salmon when this year has had one of the best sockeye returns to the Snake River in recent memory,” said Kurt Miller, executive director of Northwest RiverPartners, which represents Northwest electric utilities, plus river transportation and agriculture interests.
Hot air temperatures cause hot river temperatures and heat-related salmon die-offs are being seen in the undammed Fraser River in Canada and rivers as far north as Alaska, Miller said.
Removing the hydroelectric dams will make climate change worse and river temperatures more dangerous to salmon, he said.
He also pointed out that a 2020 study by the National Oceanic and Atmospheric Administration said the undammed Salmon River was more at risk for extreme river temperatures than the lower Snake River.
The Corps has long said that the courts lack the authority to order Snake River dam removal.
But the groups planning the lawsuit based on the Endangered Species Act argue that the U.S. Supreme Court has said that congressional authorizations for federal dams do not create exemptions to the act and cannot prevent them from being prohibited.
They told the Corps that unless the Biden administration took action on a solution to save salmon in the Columbia River and its tributaries as he pledged in March, it would file the lawsuit as soon as Sept. 18.