America's Largest Dam Removal Under Way in the Pacific Northwest

Steve Ringman/ The Seattle Times

America's Largest Dam Removal Under Way in the Pacific Northwest

Deconstructing the Elwha Dam began this past September.

By Susan Cosier
Published: January-February 2012

For the first time in a century, salmon will once again swim up Washington's Elwha River to spawn in its headwaters and tributaries. The largest dam removal in U.S. history began in mid-September when contractors started chipping away at the Elwha and Glines Canyon dams (105 and 210 feet high, respectively) in Washington State. Within three years the river, which has a 45-mile main channel and more than 100 miles of tributaries, most of which flow through Olympic National Park, will run free, revitalizing the watershed.

"This project is restoring an ecosystem within a national park from the mountains to the sea," says Brian Winter, the Elwha project manager for the National Park Service, the agency overseeing the removal, who has been working on the effort since 1983. "It will be restoration to an otherwise pristine habitat, which is fairly unique in the Pacific Northwest."

These are just two of the 241 dams that have been taken down or breached since 2006, a 20 percent increase over the preceding half-decade. Many were no longer useful, or too expensive to maintain. In California and Oregon a diverse group of stakeholders, including officials, are proposing the removal of four hydroelectric dams on the Klamath River, and when the Condit Dam on the White Salmon River in Washington was blown up this fall, the event was broadcast on television.

Between steadily declining fisheries and mounting pressures from environmentalists, owners are simply opting to do away with the structures. "Dams block fish migration and they can have some type of liability or probability of failure," says Timothy Randle, a hydraulic engineer with the U.S. Bureau of Reclamation. Despite the planned or ongoing deconstruction of several high-profile dams like the Condit, there are still an estimated 79,000 dams in the country; about three percent generate energy, while others support recreation or agriculture and other industry.

The Elwha dam, finished in 1913, and the Glines Canyon dam, built in 1927, powered a paper mill. Trapped behind the behemoths is 24 million cubic yards of sediment, enough to fill the Empire State Building a whopping 17 times. This material will settle on the shores, river bottom, and estuary, creating better habitat for fish.

All five types of salmon that originally inhabited the waters could repopulate 70 miles of the river and its tributaries, potentially boosting the population from 3,000 today to 300,000 in the next 50 to 100 years. Studies show that the fish could be a boon for the growth of plants and wildlife. "Other animals will eat the carcasses, and the nutrients will soak into the system," says George Pess, a fisheries biologist with the NOAA Northwest Fisheries Science Center. Deposits of such nutrients as nitrogen, carbon, and phosphorus from fish can fertilize areas along the river and even farther ashore. 

Beyond these benefits, the return of salmon is also critical to the Lower Elwha Klallam Tribe, the group that launched the effort to eliminate the dams in the mid-1980s. The dams not only cut off the salmon runs, they didn't align with the Klallam's beliefs about safeguarding natural resources, says Robert Elofson, 59, the river restoration project director for the tribe. "This project means that probably within my lifetime we'll start harvesting natural-run salmon again."

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Susan Cosier

Susan Cosier is former senior editor at Audubon magazine. Follow her on Twitter @susancosier.

Type: Author | From: Audubon Magazine