PARENT SESSION
Symposium #23: Dam removal as river restorations: Linking ecological, engineering, social, and legal perspectives.
Sponsored by ESA Aquatic Ecosystems Section
Organized by: D. D. Hart and N. L. Poff.
Friday, August 10, 2001. 8:00 AM to 12:00 PM. Madison Ballroom A

Dam removal: Challenges and opportunities for ecological research and watershed management.

Hart, David¹, Bushaw-Newton, Karen¹, Charles, Donald¹, Horwitz, Richard¹, Johnson, Thomas¹, Kreeger, Daniel ¹, Velinsky, David¹, ¹

ABSTRACT- Growing interest in dam removal creates unique opportunities for large-scale, quasi-experimental manipulations to probe linkages among physical, chemical, and biological processes in river ecosystems. Moreover, river restoration efforts can be enhanced by developing better models to predict the ecological effects of removing particular dams, and to assist in setting regional priorities for dam removal. We propose a research agenda to: (1) advance ecological understanding of dam removal; and (2) improve the scientific basis for dam removal decisions. To advance understanding of ecosystem responses to dam removal, it is helpful to begin by examining prior work on the ecological impacts of existing dams. More research is needed, however, to determine which of these alterations can be reversed by dam removal, how the rate of recovery varies among ecosystem components, and how restoration can be facilitated. Such research will require coordinated interdisciplinary approaches, creative sampling designs, and long-term monitoring. To improve decision-making, models are needed for predicting how ecological responses to removal vary as a function of dam attributes, river characteristics, and watershed context. These models should focus on the role of dams as barriers to fish and other species, the importance of accumulated sediments as a source of nutrients and contaminants, the effects of impoundments on water quality, and the impact of dams on physical habitats and flow regimes. We highlight these perspectives based on our experiences studying dams and dam removal in Pennsylvania.

KEY WORDS: river, restoration, dam, watershed