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
Landscape context and the biophysical response of rivers to dam removal in the United States
Dams have been a fundamental part of the U.S. national agenda over the past two hundred years. Recently, however, dam removal has emerged as a strategy for addressing aging, obsolete infrastructure and more than 1,100 dams have been removed since the 1970s. However, only 130 of these removals had any ecological or geomorphic assessments, and fewer...
Foley, Melissa M.; Magilligan, Francis J.; Torgersen, Christian E.; Major, Jon J.; Anderson, Chauncey W.; Connolly, Patrick J.; Wieferich, Daniel J.; Shafroth, Patrick B.; Evans, James E.; Infante, Dana M.; Craig, Laura Coastal habitat and biological community response to dam removal on the Elwha River
Habitat diversity and heterogeneity play a fundamental role in structuring ecological communities. Dam emplacement and removal can fundamentally alter habitat characteristics, which in turn can affect associated biological communities. Beginning in the early 1900s, the Elwha and Glines Canyon dams in Washington, USA, withheld an estimated 30...
Foley, Melissa M.; Warrick, Jonathan A.; Ritchie, Andrew C.; Stevens, Andrew W.; Shafroth, Patrick B.; Duda, Jeffrey J.; Beirne, Matthew M.; Paradis, Rebecca; Gelfenbaum, Guy R.; McCoy, Randall; Cubley, Erin S.
Dam Removal Information Portal (DRIP)—A map-based resource linking scientific studies and associated geospatial information about dam removals
The removal of dams has recently increased over historical levels due to aging infrastructure, changing societal needs, and modern safety standards rendering some dams obsolete. Where possibilities for river restoration, or improved safety, exceed the benefits of retaining a dam, removal is more often being considered as a viable option. Yet, as...
Duda, Jeffrey J.; Wieferich, Daniel J.; Bristol, R. Sky; Bellmore, J. Ryan; Hutchison, Vivian B.; Vittum, Katherine M.; Craig, Laura; Warrick, Jonathan A. Coastal change from a massive sediment input: Dam removal, Elwha River, Washington, USA
The removal of two large dams on the Elwha River, Washington, provides an ideal opportunity to study coastal morphodynamics during increased sediment supply. The dam removal project exposed ~21 million cubic meters (~30 million tonnes) of sediment in the former reservoirs, and this sediment was allowed to erode by natural river processes. Elevated...
Warrick, Jonathan A.; Gelfenbaum, Guy R.; Stevens, Andrew W.; Miller, Ian M.; Kaminsky, George M.; Foley, Melissa M. Rapid water quality change in the Elwha River estuary complex during dam removal
Dam removal in the United States is increasing as a result of structural concerns, sedimentation of reservoirs, and declining riverine ecosystem conditions. The removal of the 32 m Elwha and 64 m Glines Canyon dams from the Elwha River in Washington, U.S.A., was the largest dam removal project in North American history. During the 3 yr of dam...
Foley, Melissa M.; Duda, Jeffrey J.; Beirne, Matthew M.; Paradis, Rebecca; Ritchie, Andrew; Warrick, Jonathan A. Large-scale dam removal on the Elwha River, Washington, USA: river channel and floodplain geomorphic change
A substantial increase in fluvial sediment supply relative to transport capacity causes complex, large-magnitude changes in river and floodplain morphology downstream. Although sedimentary and geomorphic responses to sediment pulses are a fundamental part of landscape evolution, few opportunities exist to quantify those processes over field scales...
East, Amy E.; Pess, George R.; Bountry, Jennifer A.; Magirl, Christopher S.; Ritchie, Andrew C.; Logan, Joshua B.; Randle, Timothy J.; Mastin, Mark C.; Minear, Justin T.; Duda, Jeffrey J.; Liermann, Martin C.; McHenry, Michael L.; Beechie, Timothy J.; Shafroth, Patrick B. Large-scale dam removal on the Elwha River, Washington, USA: fluvial sediment load
The Elwha River restoration project, in Washington State, includes the largest dam-removal project in United States history to date. Starting September 2011, two nearly century-old dams that collectively contained 21 ± 3 million m3 of sediment were removed over the course of three years with a top-down...
Magirl, Christopher S.; Hilldale, Robert C.; Curran, Christopher A.; Duda, Jeffrey J.; Straub, Timothy D.; Domanski, Marian M.; Foreman, James R. Large-scale dam removal on the Elwha River, Washington, USA: source-to-sink sediment budget and synthesis
Understanding landscape responses to sediment supply changes constitutes a fundamental part of many problems in geomorphology, but opportunities to study such processes at field scales are rare. The phased removal of two large dams on the Elwha River, Washington, exposed 21 ± 3 million m3, or ~ 30 million ...
Warrick, Jonathan A.; Bountry, Jennifer A.; East, Amy E.; Magirl, Christopher S.; Randle, Timothy J.; Gelfenbaum, Guy R.; Ritchie, Andrew C.; Pess, George R.; Leung, Vivian; Duda, Jeff J. Sedimentology of new fluvial deposits on the Elwha River, Washington, USA, formed during large-scale dam removal
Removal of two dams 32 m and 64 m high on the Elwha River, Washington, USA, provided the first opportunity to examine river response to a dam removal and controlled sediment influx on such a large scale. Although many recent river-restoration efforts have included dam removal, large dam removals have been rare enough that their physical and...
Draut, Amy; Ritchie, Andrew C. Occupancy patterns of mammals and lentic amphibians in the Elwha River riparian zone before dam removal
The downstream transport of sediments and organics and upstream migration of anadromous fishes are key ecological processes in unregulated riverine ecosystems of the North Pacific coast, but their influence on wildlife habitats and populations is poorly documented. Removal of two large hydroelectric dams in Washington’s Elwha Valley provides...
Jenkins, Kurt J.; Chelgren, Nathan; Sager-Fradkin, K.A.; Happe, P.J.; Adams, M.J. Guidelines for monitoring and adaptively managing restoration of Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) on the Elwha River
As of January, 2014, the removal of the Elwha and Glines Canyon dams on the Elwha River, Washington, represents the largest dam decommissioning to date in the United States. Dam removal is the single largest step in meeting the goals of the Elwha River Ecosystem and Fisheries Restoration Act of 1992 (The Elwha Act) — full restoration of the...
Peters, R.J.; Duda, J.J.; Pess, G.R.; Zimmerman, M.; Crain, P.; Hughes, Z.; Wilson, A.; Liermann, M.C.; Morley, S.A.; McMillan, J.; Denton, K.; Warheit, K.
Suspended-sediment concentrations during dam decommissioning in the Elwha River, Washington
In 2011, the National Park Service commenced the incremental removal of two century-old dams along the Elwha River, Washington, in order to restore ecological and sediment-delivery processes (U.S. Department of the Interior, 1996; Duda and others, 2008, 2011; Curran and others, 2009). Elwha Dam (32-m high; 8 km from the Strait of Juan de Fuca) was...
Curran, Christopher A.; Magirl, Christopher S.; Duda, Jeffrey J.-
Date published: September 7, 2011Publications Explain Elwha River Restoration to Scientists, General Public
Two new USGS publications explain to scientists and the general public what to expect starting later this month as the historic removal of two dams from Washington’s Elwha River begins what is hoped to be a full ecosystem restoration.
Attribution: Region 9: Columbia-Pacific Northwest -
Date published: August 25, 2011
Final Beach Erosion Survey of the Elwha River Delta Before Dam Removal
The USGS on Aug. 26-27, 2011 will conduct its final beach erosion survey of the Elwha River delta before a historic dam removal begins upstream in September, in line with its ongoing study of the dams' effects on the ecosystem.
Attribution: Region 9: Columbia-Pacific Northwest -
Date published: August 4, 2011
Federal Dive Teams Conduct Underwater Study at Mouth of Elwha River
Scuba divers from the USGS and the Environmental Protection Agency are exploring and cataloging marine life at the mouth of Washington’s Elwha River. The underwater survey is taking place downstream of the Elwha and Glines Canyon Dams, which are being removed over the next three years starting this September.
Attribution: Region 9: Columbia-Pacific Northwest -
Date published: September 15, 2008Before the Dams Come Out: Scientists Measure Elwha River Conditions Now to Help Measure Dam Removal Success Tomorrow
When the Elwha and Glines Canyon dams in Washington State are torn down in 2012, scientists will be able to see — as never before — how the removal of large dams affects the restoration of ecosystems, plants, fisheries and other animals.
Attribution: Region 9: Columbia-Pacific Northwest -
Date published: September 21, 2007Biologist-Divers Complete 42-Mile Snorkel Survey of Elwha River
In one of the longest snorkel surveys ever completed in North America, fisheries biologists recently swam the length of the Elwha River - from its headwaters to its mouth - with the goal of establishing a baseline of the river's fish population before dam removal begins.