This video introduces a multi-agency team of scientists and their project to install and operate a resistance board floating weir in the Elwha River. The weir is a fish trap used within a larger program for monitoring salmon populations in the Nation's largest dam removal and river restoration project.
USGS science supporting the Elwha River Restoration Project
Mouth of the Elwha River
Former Lake Aldwell
and former site of Elwha Dam
Former Lake Mills
and former site of Glines Canyon Dam
Elwha River sediment plume
during dam removal
Mapping Elwha delta and environs
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.
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.
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.
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.
Below are data sets associated with this project.
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2018
Bathymetry and acoustic-backscatter data collected in 2016 offshore the Elwha River mouth, Washington, during USGS Field Activity 2016-605-FA
Oceanographic measurements obtained offshore of the Elwha River delta in coordination with the Elwha River Restoration Project, Washington, USA, 2010-2014
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington
Characterization of seafloor photographs near the mouth of the Elwha River during the first two years of dam removal (2011-2013)
Below are multimedia items associated with this project.
This video introduces a multi-agency team of scientists and their project to install and operate a resistance board floating weir in the Elwha River. The weir is a fish trap used within a larger program for monitoring salmon populations in the Nation's largest dam removal and river restoration project.
This video shows a virtual fly-through of a detailed, highly accurate three-dimensional model of the lower Elwha River, Washington. The video begins about 0.8 river kilometers upstream (south) of the bridge on Elwha River Road.
This video shows a virtual fly-through of a detailed, highly accurate three-dimensional model of the lower Elwha River, Washington. The video begins about 0.8 river kilometers upstream (south) of the bridge on Elwha River Road.
Below are publications associated with this project.
Littoral sediment from rivers: Patterns, rates and processes of river mouth morphodynamics
World’s largest dam removal reverses coastal erosion
Refining the Baseline Sediment Budget for the Klamath River, California
Four dams in the Klamath River Hydroelectric Project (KHP) in Oregon and California (Figure 1) are currently scheduled to be removed over a period of a few weeks or months, beginning in January 2021. The Klamath dam removal will be the largest in the world by almost all measures, and is an unprecedented opportunity to advance science of river responses to such events. The KHP contains approximatel
Conceptualizing ecological responses to dam removal: If you remove it, what's to come?
Geomorphic evolution of a gravel‐bed river under sediment‐starved vs. sediment‐rich conditions: River response to the world's largest dam removal
Understanding river response to sediment pulses is a fundamental problem in geomorphic process studies, with myriad implications for river management. However, because large sediment pulses are rare and usually unanticipated, they are seldom studied at field scale. We examine fluvial response to a massive (~20 Mt) sediment pulse released by the largest dam removal globally, on the Elwha River, Was
Do we know how much fluvial sediment reaches the sea? Decreased river monitoring of U.S. coastal rivers
River response to large‐dam removal in a Mediterranean hydroclimatic setting: Carmel River, California, USA
Removal of San Clemente Dam did more than restore fish passage
Morphodynamic evolution following sediment release from the world’s largest dam removal
Sediment pulses can cause widespread, complex changes to rivers and coastal regions. Quantifying landscape response to sediment-supply changes is a long-standing problem in geomorphology, but the unanticipated nature of most sediment pulses rarely allows for detailed measurement of associated landscape processes and evolution. The intentional removal of two large dams on the Elwha River (Washingto
Increased sediment load during a large-scale dam removal changes nearshore subtidal communities
Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington
Geomorphic responses to dam removal in the United States – a two-decade perspective
Below are data sets associated with this project.
USGS Dam Removal Information Portal (DRIP)
A tool to explore trends about dam removal science and query scientific studies that evaluate environmental response to dam removals.
Below are software products associated with this project.
Dam Removal Information Portal (DRIP)
The Dam Removal Information Portal (DRIP) is an online representation and visualization tool for the USGS Dam Removal Science Database, and provides a map-based visualization of information of dam removals and associated scientific studies.
Below are news stories associated with this project.
Below are partners associated with this project.
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.
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.
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.
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.
Below are data sets associated with this project.
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2018
Bathymetry and acoustic-backscatter data collected in 2016 offshore the Elwha River mouth, Washington, during USGS Field Activity 2016-605-FA
Oceanographic measurements obtained offshore of the Elwha River delta in coordination with the Elwha River Restoration Project, Washington, USA, 2010-2014
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington
Characterization of seafloor photographs near the mouth of the Elwha River during the first two years of dam removal (2011-2013)
Below are multimedia items associated with this project.
This video introduces a multi-agency team of scientists and their project to install and operate a resistance board floating weir in the Elwha River. The weir is a fish trap used within a larger program for monitoring salmon populations in the Nation's largest dam removal and river restoration project.
This video introduces a multi-agency team of scientists and their project to install and operate a resistance board floating weir in the Elwha River. The weir is a fish trap used within a larger program for monitoring salmon populations in the Nation's largest dam removal and river restoration project.
This video shows a virtual fly-through of a detailed, highly accurate three-dimensional model of the lower Elwha River, Washington. The video begins about 0.8 river kilometers upstream (south) of the bridge on Elwha River Road.
This video shows a virtual fly-through of a detailed, highly accurate three-dimensional model of the lower Elwha River, Washington. The video begins about 0.8 river kilometers upstream (south) of the bridge on Elwha River Road.
Below are publications associated with this project.
Littoral sediment from rivers: Patterns, rates and processes of river mouth morphodynamics
World’s largest dam removal reverses coastal erosion
Refining the Baseline Sediment Budget for the Klamath River, California
Four dams in the Klamath River Hydroelectric Project (KHP) in Oregon and California (Figure 1) are currently scheduled to be removed over a period of a few weeks or months, beginning in January 2021. The Klamath dam removal will be the largest in the world by almost all measures, and is an unprecedented opportunity to advance science of river responses to such events. The KHP contains approximatel
Conceptualizing ecological responses to dam removal: If you remove it, what's to come?
Geomorphic evolution of a gravel‐bed river under sediment‐starved vs. sediment‐rich conditions: River response to the world's largest dam removal
Understanding river response to sediment pulses is a fundamental problem in geomorphic process studies, with myriad implications for river management. However, because large sediment pulses are rare and usually unanticipated, they are seldom studied at field scale. We examine fluvial response to a massive (~20 Mt) sediment pulse released by the largest dam removal globally, on the Elwha River, Was
Do we know how much fluvial sediment reaches the sea? Decreased river monitoring of U.S. coastal rivers
River response to large‐dam removal in a Mediterranean hydroclimatic setting: Carmel River, California, USA
Removal of San Clemente Dam did more than restore fish passage
Morphodynamic evolution following sediment release from the world’s largest dam removal
Sediment pulses can cause widespread, complex changes to rivers and coastal regions. Quantifying landscape response to sediment-supply changes is a long-standing problem in geomorphology, but the unanticipated nature of most sediment pulses rarely allows for detailed measurement of associated landscape processes and evolution. The intentional removal of two large dams on the Elwha River (Washingto
Increased sediment load during a large-scale dam removal changes nearshore subtidal communities
Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington
Geomorphic responses to dam removal in the United States – a two-decade perspective
Below are data sets associated with this project.
USGS Dam Removal Information Portal (DRIP)
A tool to explore trends about dam removal science and query scientific studies that evaluate environmental response to dam removals.
Below are software products associated with this project.
Dam Removal Information Portal (DRIP)
The Dam Removal Information Portal (DRIP) is an online representation and visualization tool for the USGS Dam Removal Science Database, and provides a map-based visualization of information of dam removals and associated scientific studies.
Below are news stories associated with this project.
Below are partners associated with this project.