There can be little argument that many of the more than 90,000 dams in this country are in need of immediate attention. The catastrophic failure of two dams in Michigan last month following an extraordinary amount of rain in a relatively short period, highlights a number of issues:
- More than 60% of dams in the United States are more than 60 years old. That means they were largely constructed using construction standards and techniques that are no longer consistent with modern requirements and standards, exposing these dams to the potential for failure.
- While many dams have been carefully maintained, a number, including some very large dams, have not. The near failure of the Oroville Dam in California a couple of years ago highlighted the challenges associated with maintenance of the tallest dam in the state. Had Oroville failed, the damage caused by that failure likely would have been catastrophic.
- Climate change is resulting in more extreme weather patterns. The amount of rain that caused or contributed to the failure of the two Michigan dams exceeded amounts seen in the region for more that 30 years.
- Climate change extremes are also likely to result in longer and more extreme dry periods in at least some regions of the country, suggesting the need for more and not less storage. Removing rather than repairing dams would result in less storage.
- Construction and maintenance of dams have effects on the environment, even if the dams are well maintained. Dams can reduce access of migratory fish to spawning grounds and block the natural flow of sediment.
These issues have been argued by proponents of dam removal as well as by opponents. Furthermore, supporters of new storage capacity contend that the alleged environmental benefits of dam removal are exaggerated, that critics frequently ignore the fact that dams are a source of renewable energy storage and production, that dam removal can have its own negative ecological and economic impacts, and that the loss of storage outweighs any benefits, particularly in an era of climate change.
The issues and arguments for and against dam removal and new water storage projects have a lot in common. They consistently reference the impacts of climate change as a justification for or argument against a given project. The likelihood of more extreme climate events, both wet and dry, are generally acknowledged by both sides, but they obviously don’t agree on the solution. The likelihood that there will be extended dry periods supports arguments against dam removal and in favor of new storage. That said, extended dry periods may impact water allocations to new storage facilities that further impact other facilities and projects. The fact that there will likely also be extreme wet events resulting in dam failures like the ones in Michigan can be used to support dam removal, particularly for old and poorly maintained dams. At the same time, the availability of additional storage when extreme wet events occur is an argument used to support new storage projects.
Neither side has a monopoly on climate change arguments. Dam removal and new water storage are likely to have both favorable and potentially unfavorable impacts in an era of climate change. In our view, both types of projects can address critical climate change issues, although the decision to pursue either depends on a host of factors, including policy considerations that are specific to the project at hand.