Dam Removal: A Multidisciplinary Approach
For centuries, dams have been built to harness the power of rivers and streams across the world. Dams built during the 19th Century were used to power grist mills, saw mills and textile mills. In the 20th Century and into today, dam construction has focused on providing power for electrical grids, flood protection, and recreational purposes. The U.S. Army Corps of Engineers has identified more than 90,000 dams across the United States that are six feet tall or higher. Thousands of smaller dams also dot the landscape. While many of these dams no longer serve their original purpose, they can potentially cause environmental degradation to our nation’s waters.
So how do you go about removing a dam once it has been identified as a good candidate for removal? Here at ECS, we take a multidisciplinary approach to dam removal. It takes a top-notch team of project managers, biologists, ecologists, engineers and fluvial geomorphologists to design a successful dam removal project. Every aspect of controlling water, sediment, and protecting infrastructure and public safety must be analyzed and incorporated into the design and permitting process.
After a dam is removed, fish habitat structures can be constructed in the former reservoir to create quality habitat in the impacted stream reach. The creative use of wood and stone in cross-vanes, J-hooks, and modified mud sills all work together to create habitat for a variety of aquatic organisms and work to facilitate their life stages. These habitat features create new homes for fish and other animals once the dam is removed and they can freely move up and down the river.
Many dams are important and well-maintained. However, some dams, especially low head dams, can create dangerous hydraulic conditions that can trap canoers, kayakers, boaters or fishermen. This seems contrary to what you might think – the most dangerous dams are often the smallest.
Dams that have outlived their lifespan and are in need of significant, possibly costly maintenance are excellent removal candidates. For those dams that continue to serve their original purpose, they are similar to cars in that they need to be inspected and maintained annually by law. In either case, identifying the proper approach to each dam project is critical to achieving a successful result.