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Summary and anticipated responses to Elwha River dam removal: Chapter 9 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

January 1, 2012

Starting in September 2011, the removal of two large dams on the Elwha River will begin an unprecedented river restoration project because of the size of the dams, the volume of sediment released, the pristine watershed upstream of the dam sites, and the potential for renewing salmon populations. Ecosystem studies of the Elwha watershed indicate that the effects of almost 100 years of damming are measurable and of consequence. These effects include smaller spawning salmon populations, massive sediment retention behind the dams, coarsening of the riverbed downstream of the dams, low nutrient concentrations in the river waters, and coastal erosion that has accelerated markedly with time. During
and after the removal of these dams, the Elwha River and its ecosystems will be altered by a renewal of sediment discharge downstream of the dams and a reintroduction of salmon spawning upstream of the dams. This chapter summarizes the pre-dam and current state of the river and its coastal ecosystems, and describes the likely outcomes of river restoration on the Elwha River ecosystems.

Citation Information

Publication Year 2011
Title Summary and anticipated responses to Elwha River dam removal: Chapter 9 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal
DOI 10.3133/sir201151209
Authors Guy Gelfenbaum, Jeffrey J. Duda, Jonathan A. Warrick
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Scientific Investigations Report
Series Number 2011-5120-9
Index ID sir201151209
Record Source USGS Publications Warehouse
USGS Organization Western Fisheries Research Center