Description:

Dams, Dam Removal, and Fluvial Sediment Regimes: Contrasting Cases From the U.S. Pacific Northwest and Colombia

Over 1400 dams have been removed in the United States, whereas hydroelectric development to meet growing energy demands is proliferating along neotropical rivers. Both dam removal and construction perturb fluvial sediment regimes in a manner that can have impacts on aquatic and human systems. This talk describes dam-removal research from the U.S. Pacific Northwest aimed at understanding post-dam-removal geomorphic responses to the introduction of large volumes of impounded reservoir sediment, including on the White Salmon River, Washington, and the Clark Fork River, Montana. New dam construction and implications for sediment dynamics are also discussed, in the context of the Magdalena River, Colombia, which has exceptionally high erosion rates, hosts high freshwater biodiversity, is at the heart of human and environmental systems in Colombia, and is experiencing rapid expansion of hydroelectric dams. Combining insights from studies of dam removal and construction highlights the importance of considering both sediment regimes and geomorphic context for river ecosystem management. 

Biography
Andrew Wilcox, a Professor in the Department of Geosciences at the University of Montana, is a geomorphologist whose research entails field studies and modeling of river flow, sediment transport, and channel morphology, which he in turn seeks to relate to aquatic ecosystem processes, disturbances, and watershed management. His research focuses on quantifying sediment balances, particularly with respect to geomorphic responses to dam construction and removal; feedbacks between riparian vegetation and morphodynamics; and application of geomorphic principles to river restoration.