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Throughout the United States, more than 600,000 miles of rivers, creeks, and other waterways are
blocked by dams1. Historically, dams have served communities as a source of drinking water, power generation, flood protection,
and irrigation. While many dams continue to serve a vital purpose, a growing number are becoming archaic remnants of needs
that no longer exist. As these obsolete structures age, they provide challenges to communities that must struggle with
aging infrastructure that is costly to maintain. Aging dams also pose significant safety hazards, incur regulatory costs,
and restrict natural riverine habitats.
Since 2001, the number of high-hazard deficient dams in the United States has increased by more than 350%2. Dams are
determined to be deficient as a result of aging, deterioration, or lack of maintenance, which can create hazards to life
and property. Considering the vast majority of dams in the United States are more than 40 years in age, the number of
deficient dam structures is certain to rise.
Addressing the Issue
Communities that own failing dams are often faced with a multi-faceted dilemma. Many dams, especially very old
structures of historical significance, provide iconic landmarks for communities. Residents tend to form very strong
attachments to dams, which are highly identifiable pieces of the local landscape. Accordingly, communities are naturally
resistant when removing obsolete, failing dams is recommended, even when the other alternatives are more expensive.
Many communities around the country are faced with the issue of dam rehabilitation versus removal. More and more public
agencies are investigating alternative methods to the costly rehabilitation and maintenance that dams often require. Given
the risks to public safety and impacts to water quality and aquatic species, many communities have chosen to remove their
dams and find ways to restore rivers. These methods are often more cost effective than the long-term financial liabilities
associated with maintaining dam structures.
While many communities initially favor the rehabilitation of aging dams, the advantages of removing dam
structures and restoring rivers to their natural state have grown as attractive options for dam owners
across the nation. Restoration methods have been shown to provide economic, cultural, environmental, and
recreational benefits. Some of the advantages of dam removal include3:
- Restoration of natural riverine and fishery habitats
- Improvement of degraded aesthetics
- Mitigation of threats to life and property
- Deregulation and elimination of inspection costs
- Improved water clarity
- Normalized sediment transportation
- Improved biological diversity
1National Inventory of Dams - US Army Corps of Engineers
2Association of State Dam Safety Officials
3Wisconsin Department of Natural Resources
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