Aerial view of Elwha River Dam, Washington State
As they age, fill with silt, or water resource management priorities change, a large number of dams have been slated for removal. Most of those removed and proposed for removal have been smallish. The Elwha Dam, a decommissioned hydroelectric facility, inside the boundaries of Olympic National Park (the dam was built before the park was created) in the northwest corner of the continental United States is the largest dam to date to be put forth as a candidate for removal, and in September 2011 removal activity is scheduled to begin.
Removing a dam is very nearly as complicated as erecting one. Careful plans are necessary in order not to do great damage downstream. Fortunately the Elwha is a large river in flow but a short one, and the dam is only a few kilometers from its mouth into the Pacific at the Strait of Juan de Fuca. There is not much economic activity or infrastructure subject to damage downstream from the dam, making the removal problem a little less complex than it would be for most dams of comparable size.
Source: USGS
The blog "On Water" from the Water Resources Center Archive at the University of California, Berkeley (my graduate alma mater) is an extremely valuable resource for materials on water issues. Its primary focus is water in California and nearby western states, buts its coverage goes well outside the limits of that state and region. On 28 October it published a listing of links to sources on dam removal.
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