A lawsuit filed Thursday by salmon advocates aims to reverse a trend of high summer water temperatures on the Snake and Columbia Rivers.
The groups are asking the U.S. District Court in Seattle to compel the Environmental Protection Agency to issue a warm water pollution standard for the rivers. The standard, called the “Total Maximum Daily Load” (TMDL), sets limits on how high the water temperature can rise and still meet water quality requirements.
The EPA released a draft plan in 2003, but it was never finalized.
Salmon need cool water to complete their life cycles. Sustained water temperatures over about 70 degrees can hurt their chances of reproducing and surviving.
In 2015, drought and high temperatures in the Columbia River basin caused the premature death of an estimated 250,000 spawning sockeye salmon. This was a wake-up call for environmental and fishing groups, says Kevin Lewis of Idaho Rivers United.
“It took us realizing that rising temperatures in the Snake and Columbia River were not going to be an occasional event," he said. "It was going to be a, more often than not, standard – basically due to climate change."
Idaho Rivers United is one of five plaintiffs in the new lawsuit. The others are the Pacific Coast Federation of Fishermen’s Organizations, Snake River Waterkeeper, The Institute for Fisheries Resources and Columbia Riverkeeper.
In addition to climate change, the groups point to dams throughout the basin as a factor promoting high river temperatures.
"We have a problem with hot water on the Columbia River and the dams contribute to that," says Brett VandenHeuvel of Coloumbia Riverkeeper. "The fact that climate change is causing the heat problem to get worse faster, means that we need to take action, take some swift action."
If the lawsuit is successful, new TDML standards for temperature could bolster the case for dam removal on the Snake River.
But the idea of dam removal is controversial, and opponents say it would take a toll on the economy of the region. Dam removal is strongly opposed by farmers, ports, utilities, and others who point to benefits for the region from low-cost hydroelectricity and dam-created reservoirs that make the rivers navigable for shipping vessels.