Dam Removal: Physical, Biological, and Societal Considerations

Abstract

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.