Temperature Rises on Columbia Basin Dams

Summers in the Northwest are getting hotter and that could have killer consequences for endangered salmon. A new Environmental Protection Agency analysis released this week found that it isn’t just climate change that is causing our rivers (and the fish in them) to overheat—the primary cause of hot water in the Columbia Basin, especially in the lower Snake River, is the dams.

Credit: Scott Cushman

The EPA analysis comes just days after the States of Washington and Oregon asserted their Clean Water Act right—for the first time in history—to require eight federal Columbia River and lower Snake River dams to meet standards for water quality, including for temperature pollution. You can find Washington’s decisions here and read Oregon’s letter here.

Taken together, this means that the Army Corps of Engineers (the federal agency that operates the dams) now has to come up with a new management plan that addresses the temperature increase to the rivers caused by the dams. The question is, how will the Army Corps cool the Columbia and Snake rivers? Can it be done?

Credit: Army Corps of Engineers

Dams create large, relatively shallow, unshaded, and sluggish reservoirs that become heat sinks in the hot summer months. Salmon do poorly in water above 68 degrees Fahrenheit, a threshold that the Columbia and Snake rivers routinely exceed in the summer—sometimes for months. At Ice Harbor Dam on the Snake River, the Seattle Times reported today that on average temperature exceeds what’s safe for salmon in August 100 percent of the time!

As Seattle Times reporter Lynda Mapes wrote, "the wild Columbia was a spectacular slasher of a river, sticklebacked with bone crushing rock, swirling with sucking whirlpools, foaming with rapids, chutes and drops, and rainbowed with spray as it smashed its way through rock walls in a 1,290-mile run from B.C. to the Pacific." Today, the dams have turned the River into a series of reservoir lakes. 

If we don’t find a radically different way to operate these dams (or return to a free-flowing river) in a warming world, the fish are likely fried.

This has all added heat to the already boiling debate over the future of the lower Snake River dams. In addition to the lower Snake River dams’ known impacts—on salmon, the Southern Resident orcas that depend on salmon, commercial and recreational fisheries, and Native people's reserved rights and way of life—the dams are exacerbating the impact of climate change. They are also constricting access to the very cold, mountain rivers of Idaho. These high elevation, close-to-snowpack rivers and the millions of acres of wilderness that surround them are the refuge salmon need if they are going to weather a warmer world.

Credit: Author (Main Fork Salmon River, ID)

In 2015, a particularly hot year, an astonishing 250,000 Columbia and Snake adult sockeye salmon died in hot water. Columbia Riverkeeper (an organization that has been out in front on this issue) modeled the impact of the 2015 heat wave on the lower Snake River dam reservoirs. Columbia Riverkeeper’s report found that the reservoirs in 2015 were above 68 degrees for months due to the dams. But in a free-flowing river—i.e. without the four lower Snake River dams—the reservoirs in 2015 would have hit 68 degrees just briefly and then rebounded to cooler waters.

Credit: Columbia Riverkeeper

The loss of salmon in this part of the world would have incalculable economic, loss of jobs, and other consequences for all the people that depend on and live connected to salmon—from the mountain streams of Idaho, to the Columbia River Gorge, to the Salish Sea. We are already living under the shadow of that looming loss, as evidenced by the malnourished Southern Resident orca whales (that feed on Columbia Basin salmon this time of year), the scarcity of fishing opportunities for Columbia and Snake river tribal fishermen, the low salmon return count this year, and the early salmon fisheries closures in Idaho this spring.

In fact, in some places in the Columbia Basin, not enough adult salmon are returning home this year to even restock the fish hatcheries.

Credit: Author (Clearwater River, near Nez Perce Tribal Hatchery Complex)

The fish, orcas, and all of us salmon people are in terrible trouble.

If you look at things from a salmon’s or orca’s or conservationist’s point of view, as I admit I have a tendency to do, the solution can seem deceptively simple. It’s not. The debate over our relationship with the Columbia and Snake rivers—all they provide, from transportation to power to recreation to wildlife—is incredibly complex. These twin mega rivers of the west once produced between 10 and 16 million salmon. Today, they touch many lives and industries too.

Farmers and barge companies rely on an inundated river to operate and get their wheat, and other products, downriver and to market. The dams also produce carbon free power, an asset that I value. And one that we all should, as we work hard to accelerate the transition to a clean energy future and to stem the worst impacts of climate change.

Credit: Author (Barge transporting salmon in The Dalles, OR)

What the EPA report tells me, however, is that if we don’t do anything about the lower Snake River dams, we risk losing an abundance, a wild way of life that is at the very core of what it means to live out here in the mighty Northwest. Salmon are a keystone species in the animal world, but they connect us humans to each other as well—forming a link that spans from the mountains to the ocean, from Clearwater County to King County. If we do it right, finding a way to restore abundant, harvestable salmon runs should be an opportunity, not a cost. We should all be working towards a future that cares for and supports rural river communities, supports our hardworking wheat farmers, upgrades our transportation infrastructure, delivers affordable and reliable clean power, and honors treaty obligations to and the reserved rights of Native people. In short, a future that brings us all closer together—and is also rich with fish.

About the Authors

Giulia C.S. Good Stefani

Senior Attorney, Marine Mammals, Oceans Division, Nature Program

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