Environmental groups are asking the U.S. Army Corps of Engineers for emergency measures to reduce fish mortality caused by high water temperatures in the Columbia and Snake rivers.
Last year took a massive toll on sockeye salmon in the Columbia and Snake rivers, as high water temperatures killed hundreds of thousands of fish returning from the Pacific Ocean.
On Feb. 9, groups sent a letter to Col. Jose Aguilar in Portland criticizing the Corps’ “inability to protect returning adult salmon from high water temperatures,” and said another major die-off could push Snake River sockeye to the brink of extinction.
“If the Army Corps fails to adopt and implement emergency measures, it risks causing further massive fish kills, unauthorized take, failure of mandatory legal duties to protect endangered species and jeopardizing the continued existence of the Snake and Columbia rivers’ salmon and steelhead populations in 2016 and future years,” the letter states.
Both Columbia Riverkeeper and Snake River Waterkeeper signed onto the letter, which does not propose any specific measures but points to several statistics underlining the urgency of the situation. They emphasized 96 percent of endangered Snake River sockeye died before ever making it to Lower Granite Dam in 2015.
The Clean Water Act requires temperatures in the Columbia River to stay at or below 68 degrees to protect native salmon and steelhead. Rock Peters, senior fisheries biologist for the Army Corps’ Northwest Division, said temperatures varied in 2015 but eclipsed 70 degrees in July.
Oregon snowpack was the lowest on record for the 2015 water year, and early runoff exacerbated low flows throughout the Columbia Basin. By July, more than a quarter-million sockeye had died in the Columbia and Snake rivers — at least half the total run, according to reports. One biologist with the National Oceanic and Atmospheric Administration worried mortality could rise to 80 percent.
Environmental groups say dams are the main culprit. Peters did not specifically address the letter sent to Col. Aguilar, but said the Corps is working with NOAA and the state of Idaho on a report detailing what exactly happened in 2015, and ways they can keep the rivers cooler moving forward.
The report will also address fish passage issues on the lower Snake and Columbia dams, Peters said.
“We’re looking at various operations that could offset the (fish) ladder temperature differences,” he said. “Those discussions are going on.”
Peters said that report will be presented to the Northwest Power and Conservation Council, possibly in April. The council is made up of representatives from Oregon, Washington, Idaho and Montana, and works to balance regional power needs with fish and wildlife.
Possible emergency measures might include closing off surface collectors at the dams when water temperatures get too high. Surface collectors take in water near the surface to help with juvenile fish passage, but can introduce warmer water into the dams’ fish ladders that impede returning adults.
Another idea, Peters said, is to start catching and trucking fish at the dams earlier in the year when conditions arise. But nothing has been set in stone.
“I think we were all caught somewhat behind last year,” he said.