Dam removal has become a mainstream option for dam safety management restoring river, coastal ecosystems and the human communities that depend on them.
Researchers from Portland State University report that if the nation's aging dams are removed rather than repaired, billions of dollars could be saved, acknowledging that more data and analysis is necessary. The study compares the data of dams that have been removed with those that remain standing. It is speculated that by 2050 between 4,000 and 36,000 dams will be removed with a cost that can reach up to $25.1 billions, greater than the estimated rehabilitation costs.
At the same time, the American Society of Civil Engineers estimates more than $45 billion would be needed to repair and upgrade roughly 2,170 high-hazard dams—those that pose the greatest threat to life and property if they fail. The Association of State Dam Safety Officials estimates it would cost $64 billion to rehabilitate all of the U.S. dams that need to be brought up to safe condition. Zbigniew Grabowski, a Ph.D. candidate in PSU College of Liberal Arts and Science's Earth, Environment and Society program and the study's lead author states "I think it's time for a re-invigorated public process around managing the risks dams and aging dam infrastructure pose to public safety throughout the U.S. It's difficult to assess the actual public safety hazards and the most cost-effective ways of mitigating those hazards because the data on dams and dam removals has not been systematically compiled in a way that allows for robust analysis by government agencies or independent researchers." Grabowski said the choice between removing or rehabilitating dams is often framed as a cost-benefit tradeoff between the ecological, social and economic impacts of dams. "Yet we should also be looking at how including the public in dam safety decisions might increase the number of dams that don't make sense to rehabilitate," he said.
The authors conclude their study by stating the importance of the issue: ''Dam removal represents an inherently political practice, where decisions about appropriate human–river relations, including the role of aesthetics, history, identities, what is natural, and what is desirable all come to a head. Collaborations between communities, academics, policy makers, river dependent industries, and nongovernmental organizations will provide the democratic basis for sound dam decision‐making within a broader arc of socio‐technological evolution and environmental justice.''
Source: Portland State University