The Elwha Dam on the lower Elwha River
Elwha River dam removal study
Construction of two dams in the early 1900s on the Elwha River reduced the amount of salmon habitat in the watershed by 90%. Dam construction and other human activities also led to a loss of mainstem and floodplain habitat below the dams. The impending removal of the Elwha dams presents a unique opportunity to study recovery of a river ecosystem and its salmon after dam removal. We have focused on the following questions:
In an effort to answer these questions, we have initiated the following studies with our collaborators:
- How do long-term decreases in sediment and wood supply, and organic matter and nutrients affect large river morphology, fish habitat, and invertebrate and fish productivity?
- How do physical, chemical, and biological properties of large river ecosystems respond to large-scale, short-term increases in sediment supply, and changes to nutrients and organic matter?
- How do river ecosystems respond physically and biologically to large river restoration activities at low and high sediment supply levels?
- How do dams alter the formation and persistence of multiple off-channel habitat types? How does dam removal impact or restore those dynamics?
- What are the primary mechanisms for salmon colonization once dam removal occurs?
- What is the genetic baseline of salmonids above, between, and below the Elwha River dams?
- Establish monitoring sites at reference reaches; at instream restoration locations; and at reaches above, between, and below the Elwha River dams to monitor the following:
Baseline salmonid genetics
- Primary and secondary productivity
- Geomorphic and vegetative characteristics of the channel and floodplain
- Fish habitat
- Salmonid and non-salmonid distribution and abundance
George Pess, Tim Beechie, Sarah Morley, Martin Liermann, Peter Kiffney, and Todd Bennett; Gary Winans (Conservation Biology Division); Kurt Fresh, Brian Burke, and Kinsey Frick (Fish Ecology Division)
Michael McHenry (Lower Elwha Tribe); Brian Winter, Jerry Frelich, Steve Acker, Pat Crain, and Sam Brenkman (National Park Service, Olympic National Park); Roger Peters (U.S. Fish and Wildlife Service); Jeff Duda, Pat Shafroth (U.S. Geological Survey); Jeff Braatne and Chris Peery (University of Idaho); Bob Naiman (University of Washington); Dwight Berry and Bill Eaton (Peninsula College; Jim Allaway (Western Washington University); Mark Lorang and Ric Hauer (University of Montana); Ann Shaffer (WDFW); Holly Coe (ORISE); Kris Kloehn (ORISE)
Data collection ongoing
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