Steelhead and salmon high water temperatures

Steelhead and salmon are among those fish most sensitive to high water temperatures, and hot water has resulted in fish kills on some rivers. The hotter the water, the less dissolved oxygen is available to fish. 

US Army Corps dams, reservoirs impacted

Oregon and Washington state environmental protection agencies can require US Army Corps of Engineers’ dam and reservoir operators on the Columbia River to treat high water temperatures created by their facilities as a pollutant regulated by the state under a legal decision by the Washington Pollution Control Hearings Board (PCHB) announced June 28.

The judgment is part of an ongoing legal process and is not a final decision, but requires the Corps to include temperature pollution among the factors the Corps must address during ongoing dam recertification on the river.

The Dalles, John Day and McNary dams on the lower Columbia River will be impacted by the decision, as will dams and reservoirs on the Lower Snake River.

The Northwest Sportfishing Industry Association (NSIA), NRDC (Natural Resources Defense Council), and Columbia Riverkeeper, represented by Earthjustice, intervened in the case to support the State of Washington’s right to protect salmon from lethal river temperatures caused by the dams. The Affiliated Tribes of Northwest Indians also passed a resolution in support of temperature limits.

“The current heat wave is proof that we must take hot water in the Snake and Columbia rivers seriously,” said Brett VandenHeuvel, executive director of Columbia Riverkeeper, in a press release. The announcement “is a significant step towards holding the Army Corps accountable for the heat pollution caused by its dams and reservoirs.”

High river temperatures have also impacted sports fishermen. “Our industry is still reeling from the legacy of the 2015 drought, when hot water in the Columbia basin killed hundreds of thousands of adult salmon,” said Liz Hamilton, executive director of NSIA. “This announcement is good news for our fish, but we still need our region’s elected leaders to support inclusive solutions and swift action for salmon recovery. Thousands of jobs in the Northwest and beyond depend on our success.”

“The Army Corps must manage the dams to reduce water temperatures. If they don’t, the fish and the complex web of life and communities in the region that depend on salmon are all cooked,” said Giulia Good Stefani, senior attorney at NRDC. “During a hot summer like this one, the water behind the dams heats up like a dog bowl left in the sun and that can kill lots of salmon. For weeks and sometimes months at a time, the water behind the lower Snake River dams is too hot for salmon, and summers in the Pacific Northwest are only getting hotter.”

Phil Rigdon, superintendent for Yakama Nation Department of Natural Resources, wrote in support of the temperature limits, noting “the Yakama Nation’s history, culture and the lives of our people are intertwined with Nch’i-Wa’na (The Columbia River) and the salmon, fish, plants and animals that rely on its waters.” The Yakama Nation “has serious concerns about the impacts of climate change on the Columbia River ecosystem, and the combined impacts of dam operation and climate change,” Rigdon said.

He noted that the presence and operation of individual and multiple dams on the Columbia and Snake rivers warm the rivers to unsafe levels. “During the summer, the rivers are frequently so warm that salmon are unable to migrate upriver to spawn,” he explained.

In the early 2000s, Washington EPA issued temperature guidelines (TMDL) which placed legal limits on the dams’ hot water pollution to help ensure that the rivers will meet water quality standards and remain cool enough for salmon to survive and recover. On May 7, 2020, the Washington Dept. of Ecology issued eight separate 401 certifications, one for each dam. Those certifications were challenged, and the PCHB’s decision will require the Army Corps’ dams and reservoirs to comply with the limits.

According to a letter from the Washington Department of Ecology to the Corps regarding the current recertification of The Dalles Lock and Dam, for example, temperature standards must be incorporated into the permits now. “Doing so provides certainty and ensures that steps will be taken to manage sources of heat that contribute to increased river temperatures,” the letter states.

Oregon imposes regulations

In addition, the State of Oregon has issued an “objection letter” based on its Clean Water Act authority as a downstream state for the four Lower Columbia River dams — Bonneville, The Dalles, John Day, and McNary. In the letter, the Oregon Dept. of Environmental Quality stated it had determined “discharges from the dams violate state water quality standards, including temperature and total dissolved oxygen,” and requested a public hearing.