Dam Removal: Physical, Biological, and Societal Considerations

The American environmental movement is currently witnessing significant changes in accepted approaches to river management. Rivers once developed and altered for human benefits are being restored in a variety of manners and magnitudes, often with the sole intention of environmental enhancement. River restoration to date has primarily consisted of enhancement of geomorphic and habitat features along a specific reach of a river, or the enhancement of water quality via regulation of point and non point source pollution. However, such measures are only partially capable of accomplishing the goal of restoration: to return an ecosystem to an approximation of its pre-disturbance condition. Dams remain a significant limitation to overall restoration efforts, as there are fewer than 60 rivers with 100 km or more of free-flowing channel in the contiguous U.S. Hence, the recent realization of dam removal represents a significant development for the potential restoration of riverine environments.