Ecosystem Response During the Removal of the Elwha River Dams

Thursday, 17 December 2015: 08:00
2005 (Moscone West)
George R Pess1, Mike McHenry2, Martin C Liermann1, Raymond Moses2, Keith Denton3, John McMillan4, Samual Brenkman5, Jeffrey Duda6, Roger Peters7, Joe Anderson8 and Thomas Quinn9, (1)NOAA Seattle, Seattle, WA, United States, (2)Lower Elwha Klallam Tribe, Port Angeles, WA, United States, (3)KPD Consulting LLC, Sequim, WA, United States, (4)Trout Unlimited, Port Angeles, WA, United States, (5)National Park Service, Port Angeles, WA, United States, (6)USGS, seattle, WA, United States, (7)USFWS, Lacey, WA, United States, (8)WDFW, Olympia, WA, United States, (9)University of Washington, School of Aquatic and Fishery Sciences, seattle, WA, United States
Over the last century, the two dams blocked the upstream movement of anadromous fish to over 90% of the Elwha River watershed on the Olympic Peninsula of Washington State. These dams also restricted the downstream movement of sediment, wood, and other organic materials to the lower river and estuary. Populations of all Pacific salmon species and steelhead in the Elwha became critically low, habitat complexity decreased below the dams, and downstream coastal habitats became sediment starved. Simultaneous deconstruction of the two dams began in September 2011 was completed in September of 2014. The recent removal of the dams has been an opportunity to explore linkages among changes in sediment supply, salmonid populations, and ecosystem attributes. Preliminary findings focus on the delivery of millions of metric tonnes of sediment to the main river, its floodplain, and nearshore, the re-establishment of a natural wood delivery regime, the re-colonization of the upper watershed by anadromous fish, insights into functional relationships among salmonid populations and life history strategies, and the associated effects of all these elements on the aquatic and terrestrial foodwebs. This talk will provide an overview of the Elwha restoration project, and highlight recent changes observed during dam removal.