This project characterizes and measures sediment-related effects of landscape disturbances (such as major storms, drought, or wildfire) and river management. We focus primarily on the U.S. west coast, and our work relates to natural hazards and resource management.
Climate models project that in the future the western U.S. will experience more extreme rain events, greater wildfire activity, and more pronounced swings between extreme drought and extreme wet conditions. These changes could result in landscapes shedding more sediment from hillslopes and transporting it along rivers to the coast. At the same time, removal of aging dams is becoming common in the U.S.; dam removal (and some other human activities) releases sediment downstream, changing the river and coastal environments. Our research is guided by the questions: How does the scale of landscape response (such as the amount of sediment generated) correspond to the scale of disturbance (the amount of storm rainfall)? What controls lag times in landscape response signals—how long after a disturbance do its effects appear downstream, and how long do they last? How do superimposed disturbances, such as fire and subsequent storms, or a dam removal followed by extreme rain, combine to drive landscape evolution? How will variations in landscape sediment output affect the amount of sediment reaching the coast, and how might that affect the shape and evolution of beaches?
Currently active tasks:
1. Dam removal. Our team studies river and coastal response to sediment released by large dam removals, in collaboration with other federal, state, tribal, and academic researchers. Research efforts include long-term studies of the Elwha River, Washington (largest dam removal worldwide), the Carmel River (largest dam removal in California), and Klamath estuary (four pending dam removals in California and Oregon).
2. Landscape response to extreme rainfall. Extreme rain can cause major landslides and flooding, greatly increasing the amount of sediment moving along rivers to the coast. We study effects of extreme rain in, for example, the San Lorenzo and Tuolumne Rivers (California), collaborating with the Coastal Change Hazards program, USGS Geology, Minerals, Energy, and Geophysics Science Center, and others.
3. Post-fire sediment mobilization. Hillslopes commonly shed large quantities of sediment in the aftermath of a wildfire, with potential hazards for downstream communities, infrastructure and water supply. The size and duration of these effects vary widely among landscapes, and have not been measured in detail for many regions. We are collaborating with the National Park Service and other partners to investigate post-fire landscape evolution after the 2018 Carr Fire, northern California, a federally declared disaster. Our efforts focus on Whiskeytown National Recreation Area, evaluating sediment movement that affects Whiskeytown Lake and surrounding watersheds.
Below are other science projects associated with this project.
San Francisco Bay Area - Santa Cruz Mountains, CA (BALT-CZU)
Below are data or web applications associated with this project.
Grain size and charcoal abundance in sediment samples from Los Padres reservoir, Carmel River watershed, California
Aerial imagery and structure-from-motion data products from UAS surveys of the beaches at Fort Stevens State Park, OR, and Cape Disappointment State Park, WA
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, August 2022
Rain measurements in Santa Cruz County, California, January 2023
Rain measurements in the Dolan Fire Area, Los Padres National Forest, California, 2021 to 2022
Rain measurements in and near the CZU Lightning Complex Fire area, Santa Cruz Mountains, California, 2021 to 2022
River-channel topography, grain size, and turbidity records from the Carmel River, California, before, during, and after removal of San Clemente Dam (ver. 2.0, March 2022)
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2018
Polycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations in the San Lorenzo River, Santa Cruz, California, USA
Rain measurements in and near the CZU Lightning Complex Fire area, Santa Cruz Mountains, California, 2020 to 2021
Sediment grain-size data from the Klamath estuary, California
Bathymetry, topography and orthomosaic imagery for Whiskeytown Lake, northern California (ver. 2.0, July 2021)
Below are publications associated with this project.
Postfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards
Six years of fluvial response to a large dam removal on the Carmel River, California, USA
Midwinter dry spells amplify post-fire snowpack decline
Fires, floods and other extreme events – How watershed processes under climate change will shape our coastlines
21st-century stagnation in unvegetated sand-sea activity
Fire (plus) flood (equals) beach: Coastal response to an exceptional river sediment discharge event
Watershed sediment yield following the 2018 Carr Fire, Whiskeytown National Recreation Area, northern California
Flooding duration and volume more important than peak discharge in explaining 18 years of gravel–cobble river change
Landscape evolution in eastern Chuckwalla Valley, Riverside County, California
River floodplain abandonment and channel deepening coincide with the onset of clear-cut logging in a coastal California redwood forest
Geomorphic and sedimentary effects of modern climate change: Current and anticipated future conditions in the western United States
World’s largest dam removal reverses coastal erosion
Below are news stories associated with this project.
- Overview
This project characterizes and measures sediment-related effects of landscape disturbances (such as major storms, drought, or wildfire) and river management. We focus primarily on the U.S. west coast, and our work relates to natural hazards and resource management.
USGS scientists examining landslides in the Tuolumne watershed, California, caused by an extreme rain event in 2018. Photo credit: Ian Buckley Climate models project that in the future the western U.S. will experience more extreme rain events, greater wildfire activity, and more pronounced swings between extreme drought and extreme wet conditions. These changes could result in landscapes shedding more sediment from hillslopes and transporting it along rivers to the coast. At the same time, removal of aging dams is becoming common in the U.S.; dam removal (and some other human activities) releases sediment downstream, changing the river and coastal environments. Our research is guided by the questions: How does the scale of landscape response (such as the amount of sediment generated) correspond to the scale of disturbance (the amount of storm rainfall)? What controls lag times in landscape response signals—how long after a disturbance do its effects appear downstream, and how long do they last? How do superimposed disturbances, such as fire and subsequent storms, or a dam removal followed by extreme rain, combine to drive landscape evolution? How will variations in landscape sediment output affect the amount of sediment reaching the coast, and how might that affect the shape and evolution of beaches?
Currently active tasks:
1. Dam removal. Our team studies river and coastal response to sediment released by large dam removals, in collaboration with other federal, state, tribal, and academic researchers. Research efforts include long-term studies of the Elwha River, Washington (largest dam removal worldwide), the Carmel River (largest dam removal in California), and Klamath estuary (four pending dam removals in California and Oregon).
2. Landscape response to extreme rainfall. Extreme rain can cause major landslides and flooding, greatly increasing the amount of sediment moving along rivers to the coast. We study effects of extreme rain in, for example, the San Lorenzo and Tuolumne Rivers (California), collaborating with the Coastal Change Hazards program, USGS Geology, Minerals, Energy, and Geophysics Science Center, and others.
3. Post-fire sediment mobilization. Hillslopes commonly shed large quantities of sediment in the aftermath of a wildfire, with potential hazards for downstream communities, infrastructure and water supply. The size and duration of these effects vary widely among landscapes, and have not been measured in detail for many regions. We are collaborating with the National Park Service and other partners to investigate post-fire landscape evolution after the 2018 Carr Fire, northern California, a federally declared disaster. Our efforts focus on Whiskeytown National Recreation Area, evaluating sediment movement that affects Whiskeytown Lake and surrounding watersheds.
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. Evolution of the shoreline around the Elwha River mouth, Washington, before, during and after dam removal, 2011–2017. Two large dams were removed from the Elwha River between 2011 and 2014 in the largest dam removal worldwide thus far, releasing more than 20 million tons of sediment downstream. These images show the effects of new sediment depositing around the river mouth and being reworked by waves and currents. The Elwha River and other recent dam-removal sites are generating new understanding of ways in which river and coastal systems respond to human activity. A two-day rainstorm from January 26-28, 2021 caused numerous mudslides, debris flows, and other issues along California's coastal Highway 1 through Big Sur. This section is just north of Kirk Creek, at a drainage where mud was washed across the roadway. Plumes of the muddy runoff are clearly visible in the ocean. In the aftermath of the 2018 Carr Fire, northern California, sediment has eroded from burned hillslopes and accumulated in some areas of Whiskeytown Lake. A recent sediment deposit is shown here in the Whiskey Creek section of the lake. USGS scientists study landscape evolution after fires and storm rainfall to determine how intensively these disturbances impact affected areas and for how long. - Science
Below are other science projects associated with this project.
San Francisco Bay Area - Santa Cruz Mountains, CA (BALT-CZU)
Landslides in the San Francisco Bay Area of California impact people, infrastructure, and the environmnent, and are commonly induced by intense or prolonged rainfall associated with strong winter storms. - Data
Below are data or web applications associated with this project.
Filter Total Items: 23Grain size and charcoal abundance in sediment samples from Los Padres reservoir, Carmel River watershed, California
Sediment samples were collected from Los Padres reservoir in the Carmel River watershed, central California coast, between July 11 and 17, 2017, using a CME-45 barge-mounted drill rig, to characterize sedimentary properties in the reservoir deposits following the Soberanes Fire of 2016 and high river flows in winter 2017. Borehole samples were recovered using direct push coring with an Osterberg pAerial imagery and structure-from-motion data products from UAS surveys of the beaches at Fort Stevens State Park, OR, and Cape Disappointment State Park, WA
This data release presents aerial imagery and structure-from-motion (SfM) data products from uncrewed aerial system (UAS) surveys conducted on the ocean beaches adjacent to the Columbia River Mouth at the Oregon-Washington border. The surveys cover approximately 3 kilometers of Benson Beach at Cape Disappointment State Park north of the Columbia River mouth, in Washington, and 3 kilometers of theBathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, August 2022
Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of sediment, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams between 2011 and 2014 induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the response of a delta system to changesRain measurements in Santa Cruz County, California, January 2023
Rain gages were deployed temporarily at four sites in Santa Cruz County, California, during a series of atmospheric-river storms that delivered unusually large amounts of rain in January 2023. Data collection focused on the San Lorenzo River, and include three locations in the San Lorenzo Valley (in Boulder Creek along Hilton Drive, in Felton near Glengarry Road, and in Scotts Valley along Green VRain measurements in the Dolan Fire Area, Los Padres National Forest, California, 2021 to 2022
Rainfall measurements were collected in and near the Dolan Fire burn area, Los Padres National Forest, California. The Dolan Fire ignited on August 18, 2020. By the time of full containment on December 31, 2020, the fire had burned 518 km2 (128,050 acres) in Monterey County. Post-fire debris flows occurred in many watersheds burned by the Dolan Fire during the first post-fire wet season, in winterRain measurements in and near the CZU Lightning Complex Fire area, Santa Cruz Mountains, California, 2021 to 2022
Rainfall measurements were collected in and near the CZU Lightning Complex Fire (hereafter, "CZU Fire") burn area, Santa Cruz Mountains, California. The CZU Fire ignited in the Santa Cruz Mountains, California, on August 16, 2020. By the time of full containment on September 22, 2020, the fire had burned 350 km2 (86,510 acres) in Santa Cruz and San Mateo Counties. The U.S. Geological Survey (USGS)River-channel topography, grain size, and turbidity records from the Carmel River, California, before, during, and after removal of San Clemente Dam (ver. 2.0, March 2022)
The San Clemente Dam, built in the 1920s on the Carmel River in Monterey County, California, was removed during 2014 and 2015. The dam-removal project was the largest in California to date, and one of the largest in the U.S. This USGS data release presents data collected before, during, and after the removal of the dam. The data were collected to study how the river channel's topographic profilesBathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2018
Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of sediment, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams between 2011 and 2014 induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the response of a delta system to changesPolycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations in the San Lorenzo River, Santa Cruz, California, USA
Water from the San Lorenzo River in Santa Cruz, California, was sampled to analyze for polycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations (SSC) during the rainy seasons from 2008 to 2019 following drought conditions. The samples were collected using a US D-95 depth-integrated water sampler deployed from a bridge-box platform beneath a pedestrian bridge For each suspendeRain measurements in and near the CZU Lightning Complex Fire area, Santa Cruz Mountains, California, 2020 to 2021
The CZU Lightning Complex Fire (hereafter, "CZU Fire") ignited in the Santa Cruz Mountains, California, on August 16, 2020. By the time of full containment on September 22, 2020, the fire had burned 350 km2 (86,510 acres) in Santa Cruz and San Mateo Counties. The U.S. Geological Survey (USGS) installed four rain gages in and near the CZU Fire burn area to measure rainfall during the post-fire wetSediment grain-size data from the Klamath estuary, California
This data release includes grain-size measurements of sediment samples collected from the substrate surface and uppermost 10 cm of sediment deposits in the Klamath estuary, northern California. Samples were collected using a BMH-60 bed-material sampler deployed from a boat, or by hand trowel from subaerial or shallow-water (less than 0.5 m water depth) regions along the estuary margins and side chBathymetry, topography and orthomosaic imagery for Whiskeytown Lake, northern California (ver. 2.0, July 2021)
The Carr Fire ignited in northern California on July 23, 2018, and over the following six weeks burned almost 300,000 acres (approximately half on federal lands), resulting in a federal major-disaster declaration (DR-4382). Approximately 93 percent of the area within Whiskeytown National Recreation Area was burned extensively during the Carr Fire, including all of the landscape surrounding and dra - Publications
Below are publications associated with this project.
Filter Total Items: 22Postfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards
The steep, tectonically active terrain along the Central California (USA) coast is well known to produce deadly and destructive debris flows. However, the extent to which fire affects debris-flow susceptibility in this region is an open question. We documented the occurrence of postfire debris floods and flows following the landfall of a storm that delivered intense rainfall across multiple burn aAuthorsMatthew A. Thomas, Jason W. Kean, Scott W. McCoy, Donald N. Lindsay, Jaime Kostelnik, David B. Cavagnaro, Francis K. Rengers, Amy E. East, Jonathan Schwartz, Douglas P. Smith, Brian D. CollinsSix years of fluvial response to a large dam removal on the Carmel River, California, USA
Measuring river response to dam removal affords a rare, important opportunity to study fluvial response to sediment pulses on a large field scale. We present a before–after/control–impact study of the Carmel River, California, measuring fluvial geomorphic and grain-size evolution over 8 years, six of which postdated removal of a 32 m-high dam (one of the largest dams removed worldwide) and includeAuthorsAmy E. East, Lee R. Harrison, Douglas P. Smith, Joshua B. Logan, Rosealea BondMidwinter dry spells amplify post-fire snowpack decline
Increasing wildfire and declining snowpacks in mountain regions threaten water availability. We combine satellite-based fire detections with snow seasonality classifications to examine fire activity in California’s seasonal and ephemeral snow zones. We find a nearly tenfold increase in fire activity during 2020-2021 versus 2001-2019. Accumulation season broadband snow albedo declined 25-71% in twAuthorsBenjamin J. Hatchett, Arielle L. Koshkin, Kristen Guirguis, Karl Rittger, Anne W. Nolin, Anne Heggli, Alan M. Rhoades, Amy E. East, Erica R. Siirila-Woodburn, W. Tyler Brandt, Alexander Gershunov, Kayden HaleakalaFires, floods and other extreme events – How watershed processes under climate change will shape our coastlines
Ongoing sea-level rise has brought renewed focus on terrestrial sediment supply to the coast because of its strong influence on whether and how long beaches, marshes and other coastal landforms may persist into the future. Here, we summarise findings of sediment discharge from several coastal rivers, revealing that infrequent, large-magnitude events have disproportionate influence on the morphodynAuthorsJonathan Warrick, Amy E. East, Helen Willemien Dow21st-century stagnation in unvegetated sand-sea activity
Sand seas are vast expanses of Earth’s surface containing large areas of aeolian dunes—topographic patterns manifest from above-threshold winds and a supply of loose sand. Predictions of the role of future climate change for sand-sea activity are sparse and contradictory. Here we examine the impact of climate on all of Earth’s presently-unvegetated sand seas, using ensemble runs of an Earth SystemAuthorsAndrew Gunn, Amy E. East, Douglas J. JerolmackFire (plus) flood (equals) beach: Coastal response to an exceptional river sediment discharge event
Wildfire and post-fire rainfall have resounding effects on hillslope processes and sediment yields of mountainous landscapes. Yet, it remains unclear how fire–flood sequences influence downstream coastal littoral systems. It is timely to examine terrestrial–coastal connections because climate change is increasing the frequency, size, and intensity of wildfires, altering precipitation rates, and acAuthorsJonathan Warrick, Kilian Vos, Amy E. East, Sean VitousekWatershed sediment yield following the 2018 Carr Fire, Whiskeytown National Recreation Area, northern California
Wildfire risk has increased in recent decades over many regions, due to warming climate and other factors. Increased sediment export from recently burned landscapes can jeopardize downstream infrastructure and water resources, but physical landscape response to fire has not been quantified for some at-risk areas, including much of northern California, USA. We measured sediment yield from three watAuthorsAmy E. East, Joshua B. Logan, Peter Dartnell, Oren Lieber-Kotz, David B. Cavagnaro, Scott W. McCoy, Donald N. LindsayFlooding duration and volume more important than peak discharge in explaining 18 years of gravel–cobble river change
Floods play a critical role in geomorphic change, but whether peak magnitude, duration, volume, or frequency determines the resulting magnitude of erosion and deposition is a question often proposed in geomorphic effectiveness studies. This study investigated that question using digital elevation model differencing to compare and contrast three hydrologically distinct epochs of topographic changeAuthorsArielle Gervasi, Gregory Pasternack, Amy E. EastLandscape evolution in eastern Chuckwalla Valley, Riverside County, California
This study investigates sedimentary and geomorphic processes in eastern Chuckwalla Valley, Riverside County, California, a region of arid, basin-and-range terrain where extensive solar-energy development is planned. The objectives of this study were to (1) measure local weather parameters and use them to model aeolian sediment-transport potential; (2) identify surface sedimentary characteristics iAuthorsAmy E. East, Harrison J. Gray, Margaret Hiza Redsteer, Matthew BallmerRiver floodplain abandonment and channel deepening coincide with the onset of clear-cut logging in a coastal California redwood forest
Changes in both land use and climate can alter the balance of transport capacity and sediment supply in rivers. Hence, the primary driver of recent incision or aggradation in alluvial channels is often unclear. The San Lorenzo River on the central coast of California is one location where both climate and land use—specifically, clear-cut forestry of coastal redwoods—could explain recent vertical iAuthorsWilliam A. L. Chapman, Noah J. Finnegan, Allison M. Pfeiffer, SeanPaul La SelleGeomorphic and sedimentary effects of modern climate change: Current and anticipated future conditions in the western United States
Hydroclimatic changes associated with global warming over the past 50 years have been documented widely, but physical landscape responses are poorly understood thus far. Detecting sedimentary and geomorphic signals of modern climate change presents challenges owing to short record lengths, difficulty resolving signals in stochastic natural systems, influences of land use and tectonic activity, lonAuthorsAmy E. East, Joel B. SankeyWorld’s largest dam removal reverses coastal erosion
Coastal erosion outpaces land generation along many of the world’s deltas and a significant percentage of shorelines, and human-caused alterations to coastal sediment budgets can be important drivers of this erosion. For sediment-starved and erosion-prone coasts, large-scale enhancement of sediment supply may be an important, but poorly understood, management option. Here we provide new topographiAuthorsJonathan Warrick, Andrew W. Stevens, Ian M. Miller, Shawn R Harrison, Andrew C. Ritchie, Guy R. Gelfenbaum - News
Below are news stories associated with this project.