Like any other structure, dams require regular maintenance. When a dam no longer serves its intended function, maintenance costs can be hard to justify—and dams that fall into disrepair can be extremely dangerous. Over the past century, more than 250,000 people around the world have died from dam failures.
So, in the interest of public safety, communities with dams often decide to remove them. Dam removal is a complicated process, and it can be a highly emotional one. Sometimes dams are important landmarks. Impoundments and spillways can mimic attractive natural features like ponds and waterfalls.
One of the biggest concerns that we hear about dam removal is that it will cause flooding. That’s a common misconception. Most dams are run-of-river dams, which means they do not have any flood reduction role. Consequently, in almost all cases a dam removal will not change flood elevations downstream of the dam while lowering flood elevations upstream. In addition, we carefully design the release of impounded water during a dam removal. This “drawdown” process can take months. After releasing the impounded water, the flow downstream is the same as it was before dam removal, and catastrophic dam failure is no longer a risk.
Although dam removal isn’t the right choice in every situation, it can result in beautifully restored streams and rivers that provide important habitat connectivity and new recreational opportunities.
Pictured: the Pucker Street Dam site in Niles, Michigan on the Dowagiac River before and after removal.
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