USGS science supporting the Elwha River Restoration Project
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The Elwha River Restoration Project has reconnected the water, salmon, and sediment of a pristine river and coast of the Olympic Peninsula of Washington. Coordinated by the National Park Service, restoration of the Elwha River included the removal of two large dams that had blocked salmon and sediment passage for almost 100 years. The largest dam removal in U.S. history began in September 2011 and concluded in the summer of 2014. Salmon are once again spawning in pristine river habitats of the Olympic National Park, and sediment is once again flowing down the river and to the eroding shoreline.
Computer animation showing changes at the mouth of the Elwha River from 2011 through 2016. Brown-shaded areas are elevations above low tide; blue shades indicate seafloor depths below low tide. Watch the animation loop to see the mouth of the Elwha River grow and change as millions of tons of sediment moved downstream from Olympic National Park to the Pacific Ocean.
This Sept. 26, 2012 image from a USGS unoccupied aircraft shows the demolition of Glines Dam and Lake Mills on the Elwha River in Olympic National Park, Washington. Credit: Susan Goplen, USGS
From 2011 to 2014, the Nation’s largest dam removal project to date took place in Washington State, allowing the Elwha River to once again flow unimpeded from its origin in the Olympic Mountains to the Strait of Juan de Fuca. Nearly 100 years of sediment (30 million tons) had accumulated behind two dams, and about two-thirds of that (20 million tons) was released, dramatically affecting the river channel, surrounding estuaries, beaches, and the river mouth. USGS expertise focused on understanding and measuring the physical and ecological impacts of dam removal and recovery of this river system alongside multiple partners: Olympic National Park, Lower Elwha Klallam Tribe, Bureau of Reclamation, Washington Department of Ecology, U.S. Fish and Wildlife Service, Environmental Protection Agency, National Ocean.
USGS divers Steve Rubin and Reg Reisenbichler laying out a survey transect in the Elwha River. Credit: Ian Miller, USGS
The USGS Pacific Coastal and Marine Science Center's (PCMSC) diverse suite of data acquisition and analytical tools, as well as expertise, were utilized to assess the progress of the restoration project and to quickly adapt to changing circumstances. The PCMSC mapped the river mouth and seafloor before and after dam removal, and collected water and sediment samples to measure nutrients and other indicators of ecosystem health. Instruments placed on the seafloor near the river mouth measured current velocity, salinity, temperature, light levels, and the amount of sediment suspended in the water. Underwater cameras took photographs periodically to document the changing seafloor environment. Lidar technology recorded landscape changes resulting from the new sediment deposited along the river and the coast. Scuba divers surveyed marine life and habitats near the mouth of the river to evaluate the effects of the high sediment loads.
Before dam removal, the river and coast downstream were starved of sand and gravel essential to the ecosystem that, according to tribal oral histories, formerly supported abundant shellfish. After dam removal, sand started accumulating again along these coastal habitats, helping to reverse long-term erosion. Salmon have begun to recolonize newly available river habitat upstream from both of the former dam sites. The Lower Elwha Klallam Tribe, whose creation site had been submerged since the building of the dams, has now had this culturally significant land returned to them. These are only a few of the ways in which this restoration project has impacted the lives of Washington residents and visitors.
USGS research geologist and Center Director Guy Gelfenbaum drives a surveying personal watercraft offshore of the Elwha River delta to map changes to the seafloor. Credit: Andrew Stevens, USGS
Research geologist Amy East confers with physical scientist Josh Logan, preparing to conduct a lidar survey near the mouth of the Elwha River in Washington.
The information gleaned and lessons learned from the extensive study of the Elwha River will inform decision-making for future dam decommissioning projects. This integration was facilitated through a USGS Powell Center working group on dam removal (2014–2015) that incorporated experiences and results from dozens of small and large dam removals into a better understanding of the effects of dam deconstruction. From this work we will be better able to predict the effects of dam removal on the landscape, wildlife, and communities, and how to best engineer these projects for the safety and well-being of local communities and their natural resources.
Aerial photograph of the mouth of the Elwha River. Aerial assistance by LightHawk and plane piloted by Dr. Milton Bennett. Credit: Jeff Duda, USGS
Re-vegetation in the river valley at the Elwha River restoration site.
USGS research ecologist Jeff Duda collects discharge data on a side channel of the Elwha River. During early stages of the dam removal project, hundreds of thousands of tons of fine-grained sediment (mostly silts and sands), trapped for decades behind the dams, delivering new sediment to the lower river corridor. Credit: Chris Magirl, USGS
Aerial photograph of the mouth of the Elwha River. Aerial assistance by LightHawk and plane piloted by Dr. Hunter Handsfield. Credit: Jeff Duda, USGS
Aerial photograph of the mouth of the Elwha River. Aerial assistance by LightHawk and plane piloted by Dr. Hunter Handsfield. Credit: Jeff Duda, USGS
Elwha River dam removal-Rebirth of a river
After years of planning for the largest project of its kind, the Department of the Interior will begin removal of two dams on the Elwha River, Washington, in September 2011. For nearly 100 years, the Elwha and Glines Canyon Dams have disrupted natural processes, trapping sediment in the reservoirs and blocking fish migrations, which changed the...
Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.
A buoyant plume adjacent to a headland-Observations of the Elwha River plume
Small rivers commonly discharge into coastal settings with topographic complexities – such as headlands and islands – but these settings are underrepresented in river plume studies compared to more simplified, straight coasts. The Elwha River provides a unique opportunity to study the effects of coastal topography on a buoyant plume, because it...
Warrick, Jonathan; Stevens, Andrew W. Channel evolution on the dammed Elwha River, Washington, USA
Like many rivers in the western U.S., the Elwha River, Washington, has changed substantially over the past century in response to natural and human forcing. The lower river is affected by two upstream dams that are slated for removal as part of a major river restoration effort. In preparation for studying the effects of dam removal, we present a...
Draut, A.E.; Logan, J.B.; Mastin, M.C. Establishing spatial trends in water chemistry and stable isotopes (δ15N and δ13C) in the Elwha River prior to dam removal and salmon recolonization
Two high-head dams on the Elwha River in Washington State (USA) have changed the migratory patterns of resident and anadromous fish, limiting Pacific salmon to the lower 7.9 km of a river that historically supported large Pacific salmon runs. To document the effects of the dams prior to their removal, we measured carbon and nitrogen stable isotope...
Duda, J.J.; Coe, H.J.; Morley, S.A.; Kloehn, K.K. A universal approximation to grain size from images of non-cohesive sediment
The two-dimensional spectral decomposition of an image of sediment provides a direct statistical estimate, grid-by-number style, of the mean of all intermediate axes of all single particles within the image. We develop and test this new method which, unlike existing techniques, requires neither image processing algorithms for detection and...
Buscombe, D.; Rubin, D.M.; Warrick, J.A.
Extended abstracts from the Coastal Habitats in Puget Sound (CHIPS) 2006 Workshop
Puget Sound is the second largest estuary in the United States. Its unique geology, climate, and nutrient-rich waters produce and sustain biologically productive coastal habitats. These same natural characteristics also contribute to a high quality of life that has led to a significant growth in human population and associated development. This...
Gelfenbaum, Guy R.; Fuentes, Tracy L.; Duda, Jeffrey J.; Grossman, Eric E.; Takesue, Renee K.
Estimates of Sediment Load Prior to Dam Removal in the Elwha River, Clallam County, Washington
Years after the removal of the two dams on the Elwha River, the geomorphology and habitat of the lower river will be substantially influenced by the sediment load of the free-flowing river. To estimate the suspended-sediment load prior to removal of the dams, the U.S. Geological Survey collected suspended-sediment samples during water years 2006...
Curran, Christopher A.; Konrad, Christopher P.; Higgins, Johnna L.; Bryant, Mark K.
USGS River Ecosystem Modeling: Where Are We, How Did We Get Here, and Where Are We Going?
This report developed as an outcome of the USGS River Ecosystem Modeling Work Group, convened on February 11, 2008 as a preconference session to the second USGS Modeling Conference in Orange Beach, Ala. Work Group participants gained an understanding of the types of models currently being applied to river ecosystem studies within the USGS, learned...
Hanson, Leanne; Schrock, Robin; Waddle, Terry; Duda, Jeffrey J.; Lellis, Bill Cobble cam: Grain-size measurements of sand to boulder from digital photographs and autocorrelation analyses
A new application of the autocorrelation grain size analysis technique for mixed to coarse sediment settings has been investigated. Photographs of sand- to boulder-sized sediment along the Elwha River delta beach were taken from approximately 1??2 m above the ground surface, and detailed grain size measurements were made from 32 of these sites for...
Warrick, J.A.; Rubin, D.M.; Ruggiero, P.; Harney, J.N.; Draut, A.E.; Buscombe, D. Simulating the recovery of suspended sediment transport and river-bed stability in response to dam removal on the Elwha River, Washington
U.S. Department of the Interior is planning to remove two high dams (30 and 60 m) from the Elwha River, which will allow the river to erode sediment deposits in the reservoirs, and ultimately restore the river ecosystem. Fluvial sediment transport and deposition paradoxically represent ecological disturbance and restoration. A one-dimensional,...
Konrad, C.P. Channel Evolution on the Lower Elwha River, Washington, 1939-2006
Analyses of historical aerial photographs of the lower Elwha River, Clallam County, Washington, reveal rates and patterns of channel change in this dammed, anabranching river between 1939 and 2006. Absolute positional changes of the active-floodplain margins, which commonly exceeded 50 m over that interval, have exceeded 400 m locally. Annualized...
Draut, Amy E.; Logan, Joshua B.; McCoy, Randall E.; McHenry, Michael; Warrick, Jonathan A. Bank Topography, Bathymetry, and Current Velocity of the Lower Elwha River, Clallam County, Washington, May 2006
The removal of two dams from the mainstem of the Elwha River is expected to cause a broad range of changes to the river and nearby coastal ecosystem. The U.S. Geological Survey has documented aspects of the condition of the river to allow analysis of ecological responses to dam removal. This report documents the bank topography, river bathymetry,...
Curran, Christopher A.; Konrad, Christopher P.; Dinehart, Randal L.; Moran, Edward H.