History of Hydropower on the Elwha River

One hundred years ago, entrepreneur Thomas Aldwell saw the Elwha River's raw, natural energy and sought to harness it. Successfully obtaining investors, he formed the Olympic Power Company and began building a dam five miles upstream of the river's mouth. Aldwell's dam started operating in 1913, providing power to developing communities around the Olympic Peninsula. Growing demand led to the decision to build another hydropower project. By 1927, Glines Canyon Dam was built eight miles upstream.

The two Elwha hydropower projects supplied a significant early source of power to the region, fostering growth and industrial development. However, while electricity powered the local timber mill, fish were blocked at the base of the lower dam.


  • The cost of the entire restoration project will total approximately $324.7 million
  • The $26.9 million contract for removal of the Elwha and Glines Canyon dams was awarded in August 2010 to Barnard Construction of Bozeman, Montana. Park staff is working to identify potential impacts on visitor access and the best ways for visitors to view dam removal as it happens.
  • A $16.4 million replacement hatchery facility has been constructed on the Lower Elwha Klallam reservation to protect existing Elwha River fish stocks during dam removal.

Elwha by the Numbers

  • The Elwha River Restoration is the largest dam removal in U.S. history and second-largest restoration project in the country, second only to the Everglades
  • The Elwha River Ecosystem and Fisheries Restoration Act was signed into law by President George H. W. Bush on October 24, 1992, calling for the removal of the dams
  • Both dams have operated without a Federal Energy Regulatory Commission license since they expired in 1976
  • Experts predict the economic benefits from dam removal could total $365.6 million over 100 years from:
    • Commercial fishing (tribal and non-tribal): $36.7 million
    • Sport fishing: $10.3 million
    • Ediz Hook (currently requires $1 million annually to protect from erosion due to lack of natural sediment, blocked by dam): $1 million
    • Recreation & Tourism: $317.6 million
  • The Lower Elwha Dam has been operational since 1913, and is 105 feet high and 450 feet long
  • The Glines Canyon Dam, eight miles upstream from Elwha Dam, has been operational since 1927, and is 210 feet high and 270 feet long
  • The Elwha Dam and Lake Aldwell are the equivalent of 267 acres or about 202 football fields, containing 352.8 million cubic feet of water
  • Glines Canyon Dam and Lake Mills are the equivalent of 415 acres or about 314 football fields, containing 1.7 billion cubic feet of water
  • Sediment: approximately 13 million cubic yards behind Glines Canyon Dam and approximately 5 million cubic yards behind Elwha Dam
  • The 313 square miles of the Elwha River Valley watershed make up 19% of Olympic National Park; 83% (266 square miles) of the watershed is within Olympic National Park

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