The impact of beaver dams on the morphology of a river in the eastern United States with implications for river restoration |
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| Authors: | Joanna Crowe Curran Kristen M Cannatelli |
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| Institution: | 1. Department of Civil and Environmental Engineering, University of Virginia, Charlottesville, VA, USA;2. Interfluve Environmental, Cambridge, MA, USA |
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| Abstract: | Restoration projects in the United States typically have among the stated goals those of increasing channel stability and sediment storage within the reach. Increased interest in ecologically based restoration techniques has led to the consideration of introducing beavers to degraded channels with the hope that the construction of beaver dams will aggrade the channel. Most research on beaver dam modification to channels has focused on the long‐term effects of beavers on the landscape with data primarily from rivers in the western United States. This study illustrated that a role exists for beavers in the restoration of fine‐grained, low gradient channels. A channel on the Atlantic Coastal Plain was analyzed before, during, and after beaver dams were constructed to evaluate the lasting impact of the beaver on channel morphology. The channel was actively evolving in a former reservoir area upstream of a dam break. Colonization by the beaver focused the flow into the channel, allowed for deposition along the channel banks, and reduced the channel width such that when the beaver dams were destroyed in a flood, there was no channel migration and net sediment storage in the reach had increased. However, the majority of the deposition occurred at the channel banks, narrowing the channel width, while the channel incised between sequential beaver dams. The study indicated that where channels are unstable laterally and bank erosion is a concern, the introduction of beavers can be a useful restoration tool. However, because of the likelihood of increased channel bed erosion in a reach with multiple beaver dams, they may not be the best solution where aggradation of an incised channel bed is the desired result. Copyright © 2014 John Wiley & Sons, Ltd. |
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| Keywords: | beaver dam restoration bank stability |
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