Restoration of the Elwha River by Dam Removal, Washington

Part of the Biodiversity Crisis Curriculum Collection.

By John Thomas

The Elwha River and its many tributaries once flowed uninterrupted for a combined distance of more than seventy-five miles in Washington’s Olympic National Park—from the base of 7,000-foot-high peaks to the Strait of San Juan de Fuca, which links Puget Sound to the Pacific Ocean.

In the early 1900s, the construction of two dams blocked the river’s free flow. Because neither of these dams had fish passages, ever since then seagoing salmon and trout have been restricted to the lower five miles of the river, now severely degraded as a spawning habitat. Of the ten historical runs of salmon, cutthroat trout, and steelhead trout, the sockeye salmon run has gone extinct. Where fishers once caught 100-pound Chinook salmon, adults now rarely grow to twenty pounds. Overall, the salmon population has declined from a pre-dam estimate of 400,000 to perhaps 3,000 today.

Yet in 1992, in response to widespread support among the area’s fishers, Native Americans, and other citizens, including even the dams’ private owners, Congress passed the Elwha River Ecosystem and Fisheries Restoration Act. This historic law requires that the Elwha’s salmon and trout populations be restored to their previous abundance. An Environmental Impact Statement assessed different actions, such as removing one or both dams or building fish ladders to allow them to swim around the dams. The analysis determined that the removal of both dams was the only way to restore the populations successfully and enable the entire Elwha River ecosystem to return to its natural state. Plans project that, within ten to twenty years after the Elwha is again a free-flowing river, it can produce 400,000 adult fish annually. The U.S. Department of the Interior’s recent proposal to remove these dams—now awaiting final agreement and funding—represents the most significant effort to reverse a century of dam building and to restore the nation’s rivers and their native biodiversity.

Large-scale restoration projects such as this do not happen without broad public support. These agreements require difficult legal and political negotiations among government agencies, fishers and recreationists, conservationists, and logging, mining, and industrial interests. Most of the federal funding for dam removal and habitat restoration on the Elwha River has been allocated, but final agreement for release of the funding is still uncertain.