SS3.21 Deconstructing Rivers: The Ecological, Geomorphic, and Social Consequences of Dam Removal
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
PessGR, National Marine Fisheries Service - NWFSC, Seattle, WA, USA, george.pess@noaa.gov
McHenry, M, , Lower Elwha S'Klallam Tribe, Port Angele, WA, USA, mchenry@elwha.nsn.us
Beechie, T, J, National Marine Fisheries Service - NWFSC, Seattle, WA , USA, tim.beechie@noaa.gov
Kiffney, P, , National Marine Fisheries Service - NWFSC, Seattle, WA, USA, peter.kiffney@noaa.gov
 
RESPONSE OF THE RIVERINE ECOSYSTEM TO ALTERED SEDIMENT AND WOOD SUPPLY DOWNSTREAM OF ELWHA DAMS
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Since installation of the first Elwha dam in 1912, decreased sediment and wood supply to the lower Elwha River has resulted in river entrenchment, degeneration of floodplain habitats, decreased abundance of certain riverine habitats, and distinct patterns of juvenile salmon occupancy of these habitats. Impending removal of these dams presents an opportunity to explore linkages among changes in sediment supply, in-channel wood abundance, and habitat and ecosystem attributes. Sampling of ecosystem attributes before and after dam removal, as well as in nearby reference rivers will elucidate functional relationships among sediment and wood supply, formation and persistence of river and floodplain habitats, and resultant ecosystem dynamics. Preliminary data indicate distinct floodplain habitat types related to the connectivity of main river and off channel stream flows. Such relationships provide a basis for predicting ecosystem responses to changes in river dynamics after dam removal.