Would Removing Dams Restore Wild Salmon Runs?

Dams Generate Power, But Block Migrating Salmon

A fish ladder designed to assist salmon with crossing the Bonneville Dam on the Columbia River.
Tim Matsui/Hulton Archive/Getty Images

Dear EarthTalk: Would removing dams in the Pacific Northwest allow the wild salmon that used to thrive there return to their former abundance?Jake Garmey, Boston, MA

Before white settlement in the Pacific Northwest (pre-1850), each year some 10 million Pacific salmon—a so-called “silver tide”—swam up the Columbia and Snake Rivers to spawn at the streams and tributaries of their births. Native Americans feasted and derived much of their cultural awareness from the presence and cycles of these fish.

Today, as few as 10,000 salmon return home to the Snake River each season.

Dams Have Decimated Wild Salmon Runs

Over fishing and pollution—as well as the crossbreeding of native fish with weaker hatchery-born fish—have since taken their toll on wild salmon populations, but most analysts point to the construction of eight large hydropower dams throughout the Columbia/Snake rivers system during the middle of the 20th century as the key factor. According to noted Pacific Northwest naturalist and writer William Dietrich, 106 salmon stocks have gone extinct from Northern California to the Canadian border since the dams were built.

According to Save Our Wild Salmon, a coalition of environmental groups and commercial and sport fishing associations, dams alone are responsible for the loss of 92 percent of salmon headed out to sea and of up to 25 percent on their way back upstream. “Fish are gone entirely from almost 40 percent of their historic rivers,” says Dietrich, who adds that most of the remaining fish are at risk, too, qualifying for full protection under the Endangered Species Act.

Quite simply, the fish just cannot swim past the dams.

Dams Generate Electricity, But Destroy Migrating Salmon

The idea of removing dams to restore salmon runs is not new. Environmentalists rejoiced in 1999 when Maine removed the 162-year-old Edwards Dam on the Kennebec River to allow passage for decimated stocks of Atlantic salmon.

That dam was an obvious choice for removal, as it provided only 1/10th of one percent of Maine’s power needs, yet strained and drained 20 percent of the state’s watershed lands. Dam removal has accelerated since, with 72 of them done in 2014 alone.

Environmentalists and biologists alike are calling for the removal of dams along the Columbia and Snake Rivers. However, dams in the Pacific Northwest produce nearly seven percent of the nation’s electricity without generating greenhouse gases, and many are eager to promote hydropower as one way to reduce our reliance on foreign oil.

Elwha Dam May Redefine Northwest Salmon vs Power Debate

Meanwhile, the federal government completed the removal of the Elwha Dam on Washington State’s Olympic Peninsula. Built a century ago to generate power, the Elwha Dam used to shut off 70 miles of habitat for the more than 500,000 fish that had spawned there each year. By 2006, just 5,000 wild Pacific salmon were swimming up the Elwha River and were schooling at the base of the dam, looking for a way upstream that no longer existed. In 2014 salmon and trout were spotted in the upper reaches of the Elwha River for the first time in over one hundred years. The successes of the Elwha Dam removal will certainly impact the debate about the prospects for removing other hydropower dams in the Pacific Northwest and elsewhere.

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Edited by Frederic Beaudry