Elwha Watershed Information Resource

Due to the enormity of both the Elwha and Glines Canyon Dams and the impacts they have had on the Elwha River watershed, their demolition will set a new precedent in the fields of dam removal and river restoration. The dam removal project is the centerpiece of a multifaceted watershed restoration effort that has taken decades to prepare.

The dam removal is scheduled to begin in 2012. Once complete, the Elwha River will flow unobstructed after almost 100 years of separation. Ecosystem function and productivity will be regenerated and the wide range of benefits synonymous with a healthy watershed will emerge over short- and long-term time scales.

National Significance

Aerial view, looking south, at Glines Dam, Lake Mills Reservoir and Elwha River. Jet Lowe, NPS/OLYM Archives

No project of this magnitude has been previously attempted. While anticipated benefits resulting from the elimination of the Elwha and Glines Canyon Dams have been the subject of rigorous analysis, perhaps the most significant and overlooked benefit of this project will be the contributions made to the nascent field of the science of dam removal. A rigorous pre and post project monitoring program will provide an immense amount of data and lessons for dam removal practitioners to use in future efforts.

Currently, there is a wealth of information for practitioners to draw upon while planning dam removals. The Elwha River dam removals will help to expedite future dam removal projects by providing valuable insight and resources that will help to eliminate uncertainty.

Dam Removal in the United States

Dam removal in the U.S. is becoming increasingly common for several reasons, including:

• The numbers of dilapidated and unproductive dams are increasing, due to the rapidly aging infrastructure of dams that were built during the early stages of U.S. industrialization.
• Dams built during the 1950s and 1960s (the peak period for dam construction in the U.S.) are coming up for relicensing. Many of these dams were granted 50-year license agreements by the Federal Energy Regulatory Commission (FERC). As these permits are coming up for relicensing, the dams are under great scrutiny regarding environmental impacts.
• As with the Elwha and Glines Canyon Dams, the benefits of maintaining a great number of these dams are outweighed by the benefits realized by their removal.

United States Dam Facts (from Heinz Report)

The National Inventory of Dams catalogues more than 76,000 dams that are (A) 6-feet high or more and impound at least 50 acre-feet of water, (B) 25-feet high and impound at least 15 acre-feet of water, or (C) a potential serious hazard to people downstream.

• The potential storage behind these dams is almost equal to the nation's total annual runoff.
• Including small structures, there may be as many as 2,000,000 dams in the U.S.
• The peak construction year for dams was 1960, with over 3,000 dams completed in a single year

Learn more about the Elwha River dams project by clicking on the links below:

History of the Elwha River Dams. The Elwha and Glines Canyon Dams were built in the early 1900s to provide needed power for growing industrial communities nearby. However, the dams have had significant negative impacts on the watershed as well.
Decisions to Remove Dams. A discussion of the factors that led to the decision to remove both of the hydroelectric dams on the Elwha River.
Strategy for Dam Removal. The careful dam removal strategy will minimize negative effects from the massive release of water and sediment that are trapped behind the dams currently.

Reference

Graf, William L. 2003. "Dam Removal Research: Status and Prospects." The H. John Heinz III Center for Science, Economics and the Environment. Proceedings of the Heinz Center's Dam Removal Research Workshop, October 23-24 2002. Washington D.C. Pages 23 and 33.