I study how landscapes change over time, focusing on response to hydroclimatic and anthropogenic disturbances. These studies inform resource management as well as fundamental understanding of earth-surface processes. I am also interested in how sediment moves from source to sink, and how the sedimentary record reflects changes in sediment supply and transport.
Research Topics
Landscape Response to Climate Change
Climatic changes associated with modern global warming have been documented widely, but physical landscape responses are poorly understood. Landscape signals of modern climate change relate to human health and safety, infrastructure, water security, and ecosystems. Our project investigates landscape responses to modern climate change, primarily in the western US, focusing on slope failures, watershed sediment yields, river morphology, and aeolian (wind-blown) sediment mobilization.
Post-Fire Sediment Mobilization
Watershed sediment yields increase after fire, but by how much and with what driving factors is not well understood for some regions. Our group studies several CA wildfires, monitoring sediment yield and related processes. We have studied landscape change after seven California fires spanning 2016 to 2022.
Effects of Large Dam Removal
Colleagues and I have studied river response to large dam removals on the Elwha River, WA, and Carmel River, CA, and study the Klamath River (CA and OR) preparing for dam removals there. I helped lead a USGS Powell Center working group on the state of dam-removal science.
Landscape Response to Hydroclimatic Extremes
Western US landscapes export large sediment fluxes, due to steep terrain, tectonic activity, and potential for extreme rain. I study landscape response to hydroclimatic disturbances—drought and extreme rain. We studied sediment export from the San Lorenzo River, CA, from record rainfall in 2017; and debris flows caused by intense rain in 2018 over the Tuolumne basin. Understanding such disturbances is critical to constraining effects of extreme events on landscapes and sediment budgets.
Landscape Evolution in the Colorado River Ecosystem
From 2003 to 2017 I studied connectivity among fluvial, aeolian, and hillslope processes in the Colorado River corridor, AZ. Since 1963, dam operations have altered flows and sediment supply in the Colorado River, Grand Canyon National Park. Loss of sandbars in the dammed river reduces windblown sand supply to aeolian dunes, affecting archaeological-site stability and ecosystem properties.
Aeolian Landscape Stability
Our work quantified sediment accumulation and landscape stability in areas of the California desert considered for solar-energy projects. I also studied aeolian landscapes on the Navajo Nation, where during drought wind-blown sand mobility has destabilized ground surfaces, endangering housing and transportation, jeopardizing grazing lands, and impacting air quality.
Professional Experience
Research Geologist, 2006-present: USGS Coastal and Marine Hazards and Resources Program, Santa Cruz, CA, Principal Investigator of Landscape Response to Disturbance project
Editor-in-Chief, January 2019-present: Journal of Geophysical Research, Earth Surface
Postdoctoral Researcher, 2003-2006: USGS/UC Santa Cruz
Education and Certifications
Ph.D., Geology and Geophysics, 2003: MIT/Woods Hole Oceanographic Institution
B.S., Geological Sciences, 1997: Tufts University
Science and Products
Klamath Dam Removal Studies
Sediment Transport in Coastal Environments
Landscape Response to Disturbance
Coastal watershed and estuary restoration in the Monterey Bay area
U.S. West Coast and Alaska Marine Geohazards
USGS science supporting the Elwha River Restoration Project
Dam removal: synthesis of ecological and physical responses
Topographic survey data and digital elevation model of Oxbow Reservoir, Placer County, California, October 2022
Grain-size data for sediment samples collected in Whiskeytown Lake, northern California, in 2018 and 2019
Sediment grain-size data from the Klamath estuary, California
Rain measurements in and near the Dolan Fire Area, Los Padres National Forest, California, 2022 to 2023
Grain size and charcoal abundance in sediment samples from Los Padres reservoir, Carmel River watershed, California
Field-verified inventory of postfire hydrologic response for the 2020 CZU Lightning Complex, River, Camel, and Dolan Fires following a 26-29 January 2021 atmospheric river storm sequence
Aeolian and drainage classification data for various archaeological sites in Grand Canyon National Park along the Colorado River from 1973 to 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
Aerial imagery and structure-from-motion data products from a UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01
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)
Colored shaded-relief bathymetric map and surrounding aerial imagery of Whiskeytown Lake, California
Shifted sediment-transport regimes by climate change and amplified hydrological variability in cryosphere-fed rivers
A watershed moment for western U.S. dams
Postfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards
Archaeological sites in Grand Canyon National Park along the Colorado River are eroding owing to six decades of Glen Canyon Dam operations
Six years of fluvial response to a large dam removal on the Carmel River, California, USA
Midwinter dry spells amplify post-fire snowpack decline
Warming-driven erosion and sediment transport in cold regions
Measuring and attributing sedimentary and geomorphic responses to modern climate change: Challenges and opportunities
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
Non-USGS Publications**
ISSN: 0197-9337 , 1096-9837 (online) , 1096-9837; DOI: 10.1002/esp.5561
Draut, A.E., and Clift, P.D., 2001, Geochemical evolution of arc magmatism during arc-continent collision, South Mayo, Ireland: Geology v. 29 (6): 543–546. doi: 10.1130/0091-7613(2001)029<0543:GEOAMD>2.0.CO;2
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
Klamath Dam Removal Studies
In January of 2024, the removal of four dams along the mainstem Klamath River will allow for volitional fish passage above the dams and will create more dynamic flow and sediment transport conditions below the dams. The release of reservoir sediment to downstream river reaches during and following dam removal may result in novel water quality, sediment transport, and geomorphic conditions. The...Sediment Transport in Coastal Environments
Our research goals are to provide the scientific information, knowledge, and tools required to ensure that decisions about land and resource use, management practices, and future development in the coastal zone and adjacent watersheds can be evaluated with a complete understanding of the probable effects on coastal ecosystems and communities, and a full assessment of their vulnerability to natural...Landscape Response to Disturbance
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.Coastal watershed and estuary restoration in the Monterey Bay area
Objectives: Support further work by the USGS and collaborating federal, state, and local agencies and academic partners in analyzing the effectiveness of restoration work in coastal watersheds and estuaries in the Monterey Bay area. The USGS will play a supporting role in field efforts led by NOAA and California State University - Monterey Bay to measure physical and ecological changes in the...U.S. West Coast and Alaska Marine Geohazards
Marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. Such underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis.ByNatural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Big Sur Landslides, Deep Sea Exploration, Mapping and Characterization, Subduction Zone ScienceUSGS science supporting the Elwha River Restoration 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.Dam removal: synthesis of ecological and physical responses
Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular, interactions b - Data
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Topographic survey data and digital elevation model of Oxbow Reservoir, Placer County, California, October 2022
This data release presents topographic survey data and a digital elevation model (DEM) of Oxbow Reservoir, in Placer County, California. The U.S. Geological Survey (USGS) conducted a topographic survey of accessible regions of the reservoir sediment on 26 October 2022, when the reservoir was partially de-watered to allow repairs to the dam infrastructure following the Mosquito Fire. The survey wasGrain-size data for sediment samples collected in Whiskeytown Lake, northern California, in 2018 and 2019
This data release supersedes version 1.0, published in July 2021 at https://doi.org/10.5066/P9BHOPEP. Versioning details are documented in the accompanying Whiskeytown_VersionHistory.txt file The Carr Fire ignited in northern California in July 2018, and ultimately burned almost 300,000 acres (approximately half on federal lands), resulting in a federal major-disaster declaration (DR-4382). ApproxSediment grain-size data from the Klamath estuary, California
This data release supersedes version 1.0, published in November 2021 at https://doi.org/10.5066/P9CAZIHJ. Versioning details are documented in the accompanying Klamath_Grainsize_VersionHistory.txt file. 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. SaRain measurements in and near the Dolan Fire Area, Los Padres National Forest, California, 2022 to 2023
Rainfall measurements were collected in and near the Dolan Fire burn area, Los Padres National Forest, California. The CZU Fire ignited in Los Padres National Forest, California, 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. The U.S. Geological Survey (USGS) installed seven rain gages in and near the DolanGrain 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 pField-verified inventory of postfire hydrologic response for the 2020 CZU Lightning Complex, River, Camel, and Dolan Fires following a 26-29 January 2021 atmospheric river storm sequence
This data release is a field-verified inventory of postfire hydrologic response for the 2020 CZU (San Mateo–Santa Cruz Unit) Lightning Complex, River Fire, Camel Fire, and Dolan Fire following a 26-29 January 2021 atmospheric river storm sequence. Postfire hydrologic response types include a) no response, b) minor response, and c) major response. A “minor” response was deemed capable of impairingAeolian and drainage classification data for various archaeological sites in Grand Canyon National Park along the Colorado River from 1973 to 2022
These data were compiled to assess the risk of erosion to archaeological site preservation. The objective of the study is to evaluate changes in archaeological site condition over time as a function of two geomorphology based conceptual models that evaluate the extent to which sites are potentially affected by 1) erosion from gullies, and 2) wind-driven (aeolian) supply of river-sourced sand, respRain 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 winterAerial imagery and structure-from-motion data products from a UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01
An unoccupied aerial system (UAS) was used to acquire high-resolution imagery of the exposed reservoir delta at Los Padres Reservoir, in the Carmel River valley in central California on 1 November 2017. This survey followed sediment delivery to the reservoir by the Carmel River due to landscape response after the 2016 Soberanes Fire and high flows in winter 2017. The imagery from this survey was pRain 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 profiles - Maps
Colored shaded-relief bathymetric map and surrounding aerial imagery of Whiskeytown Lake, California
The Carr wildfire began on July 23, 2018, and burned almost 300,000 acres (approximately half on Federal lands) in northern California during the subsequent 6-week period. Over 97 percent of the area within Whiskeytown National Recreation Area, California, burned during the 2018 Carr wildfire, including the entire landscape that surrounds and drains into Whiskeytown Lake. Shortly after the Carr wi - Multimedia
- Publications
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Shifted sediment-transport regimes by climate change and amplified hydrological variability in cryosphere-fed rivers
Climate change affects cryosphere-fed rivers and alters seasonal sediment dynamics, affecting cyclical fluvial material supply and year-round water-food-energy provisions to downstream communities. Here, we demonstrate seasonal sediment-transport regime shifts from the 1960s to 2000s in four cryosphere-fed rivers characterized by glacial, nival, pluvial, and mixed regimes, respectively. Spring seeAuthorsTinghu Zhang, Dongfeng Li, Amy E. East, Albert J. Kettner, James L. Best, Jinren Ni, Xixi LuA watershed moment for western U.S. dams
The summer of 2023 is a notable time for water-resource management in the western United States: Glen Canyon Dam, on the Colorado River, turns 60 years old while the largest dam-removal project in history is beginning on the Klamath River. This commentary discusses these events in the context of a changing paradigm for dam and reservoir management in this region. Since the era of large dam buildinAuthorsAmy E. East, Gordon E. GrantPostfire 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. CollinsArchaeological sites in Grand Canyon National Park along the Colorado River are eroding owing to six decades of Glen Canyon Dam operations
The archaeological record documenting human history in deserts is commonly concentrated along rivers in terraces or other landforms built by river sediment deposits. Today that record is at risk in many river valleys owing to human resource and infrastructure development activities, including the construction and operation of dams. We assessed the effects of the operations of Glen Canyon Dam – whiAuthorsJoel B. Sankey, Amy E. East, Helen C. Fairley, Joshua Caster, Jennifer Dierker, Ellen Brennan, Lonnie Pilkington, Nathaniel Dylan Bransky, Alan KasprakSix 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 HaleakalaWarming-driven erosion and sediment transport in cold regions
Rapid atmospheric warming since the mid-twentieth century has increased temperature-dependent erosion and sediment-transport processes in cold environments, affecting food, energy and water security. In this Review, we summarize landscape changes in cold environments and provide a global inventory of increases in erosion and sediment yield driven by cryosphere degradation. Anthropogenic climate chAuthorsTinghu Zhang, Dongfeng Li, Amy E. East, Desmond E. Walling, Stuart N. Lane, Irina Overeem, Achim A. Beylich, Michele N Koppes, Xixi LuMeasuring and attributing sedimentary and geomorphic responses to modern climate change: Challenges and opportunities
Today, climate change is affecting virtually all terrestrial and nearshore settings. This commentary discusses the challenges of measuring climate-driven physical landscape responses to modern global warming: short and incomplete data records, land use and seismicity masking climatic effects, biases in data availability and resolution, and signal attenuation in sedimentary systems. We identify oppAuthorsAmy E. East, Jonathan Warrick, Dongfeng Li, Joel B. Sankey, Margaret H. Redsteer, Ann E. Gibbs, Jeffrey A. Coe, Patrick L. BarnardFires, 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. LindsayNon-USGS Publications**
East, Amy E; Harrison, Lee R; Smith, Douglas P; Logan, Joshua B; Bond, Rosealea M, Six years of fluvial response to a large dam removal on the Carmel River, California, USA: Earth surface processes and landforms : the journal of the British Geomorphological Research Group, 2023
ISSN: 0197-9337 , 1096-9837 (online) , 1096-9837; DOI: 10.1002/esp.5561
Draut, A.E., and Clift, P.D., 2001, Geochemical evolution of arc magmatism during arc-continent collision, South Mayo, Ireland: Geology v. 29 (6): 543–546. doi: 10.1130/0091-7613(2001)029<0543:GEOAMD>2.0.CO;2**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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