I try to pay attention to what’s happening on the Columbia River. And I thought I had a handle on things generally. But I didn’t know that the river has been exceeding the temperature limit under the Clean Water Act for more than a decade. Did you know that?
My discovery was prompted by an e-mail from Columbia Riverkeeper. A group of volunteers takes water samples on the mainstem of the river every year and submits their findings to the Washington and Oregon agencies that enforce Clean Water Act rules.
The legal limit for Columbia water temperature is 68 degrees to protect salmon and steelhead in the mainstem of the river (it’s lower in tributaries and spawning grounds). Over the past two years, Columbia Riverkeepr volunteers found 70-degree water in much of the mainstem.
“Salmon can’t live in water that temperature for very long,” said Lorri Epsein, Columbia Riverkeeper’s water quality coordinator. “They can pass through it. If they can get through it and get to cold water they’re fine. That means cold water refugia becomes critically important, but a lot of the Columbia is reaching these high temperatures.”
Agnes Lut, Columbia River coordinator for the Oregon Department of Environmental Quality, said yes, her agency knows temperatures on the Columbia are exceeding the Clean Water Act limits. And not just in the past two years, she said. It’s been this way since at least 2000.
The Clean Water Act has a method of addressing this problem. It’s a process called total maximum daily load (TMDL) that identifies the sources of the problem and then sets a roadmap for reducing those sources so the entire water body meets water quality standards.
Regulators started this process by listing the Columbia as an impaired water body more than a decade ago, Lut said. But then the Biological Opinion for the hydropower system stole the spotlight:
“Back in 2000 the states of Oregon and Washington started working with Environmental Protection Agency to develop a TMDL. But that got put on the back burner. We have yet to restart that work. What those initial findings found is the temperatures on the mainstem is controlled by the dams. How much water is in storage and how much water moves through them, and the magnitude of the water spilling over them.”
The more Columbia River water sits around in dam reservoirs – especially in the summer – the warmer it gets. The water can also heat up when there’s fewer trees along the river banks shading the water from the sun, when industries discharge warm water into the river or when storm water washes off hot pavement.
The problem of water temperature has been discussed in the Biological Opinion for the hydro system, Lut said. It gets discussed all the time. But, while the dam management plan is in limbo, it seems, the water temperature violations will be hard to address.
“No specific window or time limit,” Lut said. “We try to develop TMDLs within a reasonable amount of time. But it depends on listing, where the pollutant is and the extent of the problem. With the Columbia River temperature TMDL, we would take into account Oregon, Washington and Idaho because of the Snake River. And that includes all the industries, municipalities, hydropower. It’s a really big effort to include all these entities. In order to make an impact on temperature, you’d have to look at the whole mainstem from Canada down. Grand Coulee does control a lot of what we see in the Oregon reaches of the river.”
Epstein noted that the Columbia isn’t necessarily managed with temperature in mind. There are energy, flood control and irrigation considerations to be made throughout the basin. But as it gets warmer, she said, it gets less hospitable to salmon and steelhead and the more inviting to invasive species.
“Salmon like to be in cold water and the Columbia is no longer a cold-water environment,” she said. “We’re starting to see more warm-water species like bass and pike minnow in the river. They’re happy in the Columbia, and salmon are stressed. Even at temperatures that aren’t reaching that lethal limit, if salmon are stressed, they’re more susceptible to disease and it affects their migration and growth rates.”
Now there’s a whole other conversation I’d like to have with the Corps of Engineers about managing dams for water temperature. I just set up an interview with Dave Ponganis, the Corps Chief of Planning and Environmental Resources. To be continued…