The combination of climate change and dams on the Snake and Columbia Rivers has raised the summer temperature of the rivers by nearly three degrees Fahrenheit (1.5 degrees Celsius), according to a new report released by the Environmental Protection Agency.
As a result, the temperatures of the rivers during the warm months of the year have sometimes exceeded 70 degrees Fahrenheit, which has killed migrating salmon. The reservoirs created by the dams raised the temperature of the rivers that would naturally be lower if allowed to flow freely.
In an attempt to address the problem, the Washington State Department of Ecology will aim to set new regulations on dams on the two rivers to bring the water temperature down. Washington state has had a water temperature limit of 68 degrees Fahrenheit in state waters, but the regulation has never been enforced on federal dams. The Department of Ecology will hear public comments on the proposed regulations, which could include releasing cold water from the depths of reservoirs, and installing more pumps to move cool water into fish ladders.
“This is a big deal,” Heather Bartlett, head of the Department of Ecology’s water-quality department, told the Seattle Times. “We want for the first time to have parity at federal dams with the nonfederal dams. They are either meeting state standards, or they have set up a strategy to meet them.”
Bartlett said that it would be up to dam officials to determine how they would begin to comply with the state regulations.
Scientists predict a difficult future for salmon as the globe and bodies of water heat up. Some of these effects are already being seen – in 2015, 95 percent of sockeye salmon migrating back to the Stanley Basin of Idaho died as a result of heat.
Image courtesy of Wikimedia Commons
