BOISE, Idaho — An Idaho utility will dismiss its lawsuit against the U.S. Environmental Protection Agency because it has now approved allowing warmer water temperatures in an area where federally protected fall chinook salmon reproduce.
Idaho Power in documents filed earlier this week in U.S. District Court says the EPA has approved allowing the warmer temperatures in the Snake River below the Hells Canyon Complex on the Idaho-Oregon line. The National Marines Fisheries Service says the change is not likely to jeopardize salmon or their critical habitat.
“We are happy with EPA’s decision to approve the site-specific criteria,” Idaho Power spokesman Brad Bowlin said in an email.
Idaho Power says allowing warmer water below the dams could reduce the cost of electricity and save customers up to $100 million over 50 years.
Hells Canyon is a mile-deep canyon carved by the Snake River, much of it popular for recreation but inaccessible by road. The three-dam Hells Canyon Complex built from the late 1950s through the 1960s partially tamed the river.
Snake River fall chinook were listed as threatened under the Endangered Species Act in the 1990s. A recovery plan released in 2017 identified the Snake River below the dams as the best spot for the cold-water species to boost numbers of naturally reproducing spawning fish.
When the water temperature standards aren’t met, Idaho Power must pay for mitigation for potentially harming fall chinook salmon. The proposed temperature standard change would mean Idaho Power would have to pay for less mitigation, which involves improving habitat upstream of the dams with the goal of reducing water temperatures.
Specifically, the new proposed temperature standards would raise the allowable water temperature below the dams from 55.4 degrees to 58 degrees from Oct. 23 to Nov. 6. Those two weeks are critical for fall chinook that are spawning and putting eggs in river bed gravel that might not survive if the water gets too warm.
Idaho Power when it filed the lawsuit in 2018 said river temperatures under the current standard have never been met, with records going back to 1991.