Oceanographer with the USGS Pacific Coastal and Marine Science Center
Explore my published data sets on USGS ScienceBase, or choose the Data and Tools tab below.
Education and Certifications
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR
M.S., Oceanography, November 2004Humboldt State University, Arcata, CA
B.S., Oceanography, May 2002 (with honors)
Science and Products
Estuaries and large river deltas in the Pacific Northwest
Essential habitat for wild salmon and other wildlife borders river deltas and estuaries in the Pacific Northwest. These estuaries also support industry, agriculture, and a large human population that’s expected to double by the year 2060, but each could suffer from more severe river floods, higher sea level, and storm surges caused by climate change.
Exploring the USGS Science Data Life Cycle in the Cloud
Executive Summary Traditionally in the USGS, data is processed and analyzed on local researcher computers, then moved to centralized, remote computers for preservation and publishing (ScienceBase, Pubs Warehouse). This approach requires each researcher to have the necessary hardware and software for processing and analysis, and also to bring all external data required for the workflow over the int
Filter Total Items: 30
Modeling surface gravity waves on a schematized ancient lake on Mars
This data release provides a wave model application and wave parameters derived from simulations of a schematized ancient lake on Mars. The phase-averaged wave model, SWAN, was applied within the Delft3D modeling system (Deltares, 2018) with reduced gravity and a range of atmospheric densities and wind speeds to simulate potential conditions that could generate wind waves on Mars. Wave modeling pr
Bathymetry, 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 changes
Time-series measurements of pressure, conductivity, temperature, and water level collected in Puget Sound and Bellingham Bay, Washington, USA, 2018 to 2021
Pressure, conductivity, temperature, and water level relative the North American Vertical Datum of 1988 (NAVD88) were measured at seven locations in Puget Sound and Bellingham Bay, Washington, USA, from November 2, 2018 to June 4, 2021. These data were collected using submersible pressure-conductivity-temperature sensors mounted on piers to support studies of extreme water levels and flooding haza
Beach topography and nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon
This data release presents beach topography and nearshore bathymetry data from repeated surveys performed by a team of scientists from the U.S. Geological Survey, Washington State Department of Ecology, and Oregon State University in the Columbia River littoral cell (CRLC), Washington and Oregon. The CRLC extends approximately 165 kilometers between Point Grenville (PG), Washington, and Tillamook
Eelgrass distributions and bathymetry of Bellingham Bay, Washington, 2019
This data release presents eelgrass distributions and bathymetry data derived from acoustic surveys of Bellingham Bay, Washington. Survey operations were conducted between February 16 and February 21, 2019 (USGS Field Activity Number 2019-606-FA) by a team of scientists from the U.S. Geological Survey Pacific Coastal and Marine Science Center and Washington State Department of Ecology. Eelgrass an
Hydrodynamic and sediment transport model of San Pablo Bay, California, Nov-Dec 2014
A three-dimensional hydrodynamic and sediment transport model of San Pablo and Suisun Bays was constructed using the Delft3D4 (D3D) modeling suite (Deltares, 2021a) to simulate water levels, flow, waves, and suspended sediment for time period of Nov 1 to Dec 31, 2014. This data release describes the construction and validation of the model application and provides input files suitable to run the m
Hydrodynamic model of the lower Columbia River, Washington and Oregon, 2017-2020
A three-dimensional hydrodynamic model of the lower Columbia River (LCR) was constructed using the Delft3D Flexible Mesh (DFM) modeling suite to simulate water levels, flow, and seabed stresses between January 1, 2017, and April 20, 2020. This data release describes the construction and validation of the model application and provides input files suitable to run the model on Delft3D Flexible Mesh
Aerial imagery and structure-from-motion derived data products from UAS survey of the Liberty Island Conservation Bank Wildlands restoration site, Sacramento-San Joaquin Delta, California, October 2018
Unmanned aerial systems (UAS) were used to acquire high-resolution imagery of the Liberty Island Conservation Bank Wildlands restoration site in the Sacramento-San Joaquin Delta in California, with the goal of using structure-from-motion (SfM) photogrammetric techniques to derive a digital surface model, orthomosaic imagery, and a topographic point cloud. The survey was conducted using two Depart
Eelgrass distributions and bathymetry of the Nisqually River delta, Washington
This data release presents eelgrass distributions and bathymetric data from repeated surveys performed on the Nisqually River delta to document interannual changes in eelgrass abundance and coastal morphology following the removal of dikes in 2009 that restored tidal processes to over 300 ha of former freshwater wetlands. Survey operations were conducted by a team of scientists from the U.S. Geolo
Sediment transport and aquatic vegetation data from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
We measured currents, suspended-sediment concentration (SSC), bed sediment characteristics, and vegetation biomass density in the Sacramento-San Joaquin Delta in 2017-2018, as part of a project investigating the influence of invasive aquatic vegetation (IAV) on flow and sediment flux. This data release includes data from three sites: Lindsey Slough (April 2017), Middle River (March 2018) and the l
Bathymetry, topography, and acoustic backscatter data, and a digital elevation model (DEM) of the Cache Slough Complex and Sacramento River Deep Water Ship Channel, Sacramento-San Joaquin Delta, California
This data release presents bathymetric and topographic data from surveys performed between 2017 and 2018 in the Cache Slough Complex and the Sacramento River Deep Water Ship Channel (DWSC), northern Sacramento-San Joaquin Delta, California. The shallow, highly vegetated aquatic habitats of this region necessitated a variety of survey platforms and techniques. In the deeper channels, swath bathymet
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2017
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 changes
Filter Total Items: 28
Ancient winds, waves, and atmosphere in Gale Crater, Mars, inferred from sedimentary structures and wave modeling
Wave modeling and analysis of sedimentary structures were used to evaluate whether four examples of symmetrical, reversing, or straight-crested bedforms in Gale crater sandstones are preserved wave ripples; deposition by waves would demonstrate that the lake was not covered by ice at that time. Wave modeling indicates that regardless of atmospheric density, winds that exceeded the threshold of aeo
Cohesive sediment modeling in a shallow estuary: Model and environmental implications of sediment parameter variation
Numerical models of sediment transport in estuarine systems rely on parameter values that are often poorly constrained and can vary on timescales relevant to model processes. The selection of parameter values can affect the accuracy of model predictions, while environmental variation of these parameters can impact the temporal and spatial ranges of sediment fluxes, erosion, and deposition in the r
Sediment export and impacts associated with river delta channelization compound estuary vulnerability to sea-level rise, Skagit River Delta, Washington, USA
Improved understanding of the budget and retention of sediment in river deltas is becoming increasingly important to mitigate and plan for impacts expected with sea level rise. In this study, analyses of historical bathymetric change, sediment core stratigraphy, and modeling are used to evaluate the sediment budget and environmental response of the largest river delta in the U.S. Pacific Northwest
Observations of coastal change and numerical modeling of sediment-transport pathways at the mouth of the Columbia River and its adjacent littoral cell
Bathymetric and topographic surveys performed annually along the coastlines of northern Oregon and southwestern Washington documented changes in beach and nearshore morphology between 2014 and 2019. Volume change analysis revealed measurable localized erosion and deposition throughout the study area, but significant net erosion at the regional scale (several kilometers [km]) was limited to Benson
World’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 topographi
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
By
Ecosystems, Natural Hazards, Water Resources, Coastal and Marine Hazards and Resources Program, Fisheries Program, Arizona Water Science Center, Pacific Coastal and Marine Science Center, Washington Water Science Center, Western Fisheries Research Center, Sediment Lab Suite and Carbon Analysis Laboratory
A regime shift in sediment export from a coastal watershed during a record wet winter, California: Implications for landscape response to hydroclimatic extremes
Small, steep watersheds are prolific sediment sources from which sediment flux is highly sensitive to climatic changes. Storm intensity and frequency are widely expected to increase during the 21st century, and so assessing the response of small, steep watersheds to extreme rainfall is essential to understanding landscape response to climate change. During record winter rainfall in 2016–2017, the
Investigation of input reduction techniques for morphodynamic modeling of complex inlets with baroclinic forcing
The Mouth of the Columbia River (MCR) is a complex estuary inlet system characterized by a buoyant plume created
by high freshwater flows from the Columbia River into the Pacific Ocean. Data obtained during two major field
campaigns have resulted in a comprehensive dataset of hydrodynamics and sediment transport under high (2013) and
low (2005) river flow conditions. Through the analysis of this d
Increased sediment load during a large-scale dam removal changes nearshore subtidal communities
The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx—over 10 million tonnes—during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal commun
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 million tonnes of sediment from river, coastal, and near
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 rates of sand and gravel sediment transport in the
Large-scale dam removal on the Elwha River, Washington, USA: coastal geomorphic change
Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of mud, sand, and gravel since 1927, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams, initiated in September 2011, induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the geomo
Pre-USGS Publications
Stevens, A.W. , Wheatcroft, R.A., Wiberg, P.L., 2007, Seabed properties and sediment erodibility along the western Adriatic margin, Italy: Continental Shelf Research, v. 27, i. 3–4, pp. 400-416, doi: 10.1016/j.csr.2005.09.009
Wheatcroft, R.A., Stevens, A.W., Hunt, L.M., Milligan, T.G., 2006, The large-scale distribution and internal geometry of the fall 2000 Po River flood deposit: Evidence from digital X-radiography: Continental Shelf Research, v. 26, i. 4, pp. 499-516, doi: 10.1016/j.csr.2006.01.002
Borgeld, J.C., and A.W. Stevens, 2005, Humboldt Bay, California, surface sediments 2000-01, in Schlosser, S.C., and R. Rasmussen, eds., Proceedings of the Humboldt Bay symposium; Current perspectives on the physical and biological processes of Humboldt Bay, p. 51-64
Science and Products
- Science
Estuaries and large river deltas in the Pacific Northwest
Essential habitat for wild salmon and other wildlife borders river deltas and estuaries in the Pacific Northwest. These estuaries also support industry, agriculture, and a large human population that’s expected to double by the year 2060, but each could suffer from more severe river floods, higher sea level, and storm surges caused by climate change.Exploring the USGS Science Data Life Cycle in the Cloud
Executive Summary Traditionally in the USGS, data is processed and analyzed on local researcher computers, then moved to centralized, remote computers for preservation and publishing (ScienceBase, Pubs Warehouse). This approach requires each researcher to have the necessary hardware and software for processing and analysis, and also to bring all external data required for the workflow over the int - Data
Filter Total Items: 30
Modeling surface gravity waves on a schematized ancient lake on Mars
This data release provides a wave model application and wave parameters derived from simulations of a schematized ancient lake on Mars. The phase-averaged wave model, SWAN, was applied within the Delft3D modeling system (Deltares, 2018) with reduced gravity and a range of atmospheric densities and wind speeds to simulate potential conditions that could generate wind waves on Mars. Wave modeling prBathymetry, 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 changesTime-series measurements of pressure, conductivity, temperature, and water level collected in Puget Sound and Bellingham Bay, Washington, USA, 2018 to 2021
Pressure, conductivity, temperature, and water level relative the North American Vertical Datum of 1988 (NAVD88) were measured at seven locations in Puget Sound and Bellingham Bay, Washington, USA, from November 2, 2018 to June 4, 2021. These data were collected using submersible pressure-conductivity-temperature sensors mounted on piers to support studies of extreme water levels and flooding hazaBeach topography and nearshore bathymetry of the Columbia River littoral cell, Washington and Oregon
This data release presents beach topography and nearshore bathymetry data from repeated surveys performed by a team of scientists from the U.S. Geological Survey, Washington State Department of Ecology, and Oregon State University in the Columbia River littoral cell (CRLC), Washington and Oregon. The CRLC extends approximately 165 kilometers between Point Grenville (PG), Washington, and TillamookEelgrass distributions and bathymetry of Bellingham Bay, Washington, 2019
This data release presents eelgrass distributions and bathymetry data derived from acoustic surveys of Bellingham Bay, Washington. Survey operations were conducted between February 16 and February 21, 2019 (USGS Field Activity Number 2019-606-FA) by a team of scientists from the U.S. Geological Survey Pacific Coastal and Marine Science Center and Washington State Department of Ecology. Eelgrass anHydrodynamic and sediment transport model of San Pablo Bay, California, Nov-Dec 2014
A three-dimensional hydrodynamic and sediment transport model of San Pablo and Suisun Bays was constructed using the Delft3D4 (D3D) modeling suite (Deltares, 2021a) to simulate water levels, flow, waves, and suspended sediment for time period of Nov 1 to Dec 31, 2014. This data release describes the construction and validation of the model application and provides input files suitable to run the mHydrodynamic model of the lower Columbia River, Washington and Oregon, 2017-2020
A three-dimensional hydrodynamic model of the lower Columbia River (LCR) was constructed using the Delft3D Flexible Mesh (DFM) modeling suite to simulate water levels, flow, and seabed stresses between January 1, 2017, and April 20, 2020. This data release describes the construction and validation of the model application and provides input files suitable to run the model on Delft3D Flexible MeshAerial imagery and structure-from-motion derived data products from UAS survey of the Liberty Island Conservation Bank Wildlands restoration site, Sacramento-San Joaquin Delta, California, October 2018
Unmanned aerial systems (UAS) were used to acquire high-resolution imagery of the Liberty Island Conservation Bank Wildlands restoration site in the Sacramento-San Joaquin Delta in California, with the goal of using structure-from-motion (SfM) photogrammetric techniques to derive a digital surface model, orthomosaic imagery, and a topographic point cloud. The survey was conducted using two DepartEelgrass distributions and bathymetry of the Nisqually River delta, Washington
This data release presents eelgrass distributions and bathymetric data from repeated surveys performed on the Nisqually River delta to document interannual changes in eelgrass abundance and coastal morphology following the removal of dikes in 2009 that restored tidal processes to over 300 ha of former freshwater wetlands. Survey operations were conducted by a team of scientists from the U.S. GeoloSediment transport and aquatic vegetation data from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
We measured currents, suspended-sediment concentration (SSC), bed sediment characteristics, and vegetation biomass density in the Sacramento-San Joaquin Delta in 2017-2018, as part of a project investigating the influence of invasive aquatic vegetation (IAV) on flow and sediment flux. This data release includes data from three sites: Lindsey Slough (April 2017), Middle River (March 2018) and the lBathymetry, topography, and acoustic backscatter data, and a digital elevation model (DEM) of the Cache Slough Complex and Sacramento River Deep Water Ship Channel, Sacramento-San Joaquin Delta, California
This data release presents bathymetric and topographic data from surveys performed between 2017 and 2018 in the Cache Slough Complex and the Sacramento River Deep Water Ship Channel (DWSC), northern Sacramento-San Joaquin Delta, California. The shallow, highly vegetated aquatic habitats of this region necessitated a variety of survey platforms and techniques. In the deeper channels, swath bathymetBathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2017
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 changes - Publications
Filter Total Items: 28
Ancient winds, waves, and atmosphere in Gale Crater, Mars, inferred from sedimentary structures and wave modeling
Wave modeling and analysis of sedimentary structures were used to evaluate whether four examples of symmetrical, reversing, or straight-crested bedforms in Gale crater sandstones are preserved wave ripples; deposition by waves would demonstrate that the lake was not covered by ice at that time. Wave modeling indicates that regardless of atmospheric density, winds that exceeded the threshold of aeoCohesive sediment modeling in a shallow estuary: Model and environmental implications of sediment parameter variation
Numerical models of sediment transport in estuarine systems rely on parameter values that are often poorly constrained and can vary on timescales relevant to model processes. The selection of parameter values can affect the accuracy of model predictions, while environmental variation of these parameters can impact the temporal and spatial ranges of sediment fluxes, erosion, and deposition in the rSediment export and impacts associated with river delta channelization compound estuary vulnerability to sea-level rise, Skagit River Delta, Washington, USA
Improved understanding of the budget and retention of sediment in river deltas is becoming increasingly important to mitigate and plan for impacts expected with sea level rise. In this study, analyses of historical bathymetric change, sediment core stratigraphy, and modeling are used to evaluate the sediment budget and environmental response of the largest river delta in the U.S. Pacific NorthwestObservations of coastal change and numerical modeling of sediment-transport pathways at the mouth of the Columbia River and its adjacent littoral cell
Bathymetric and topographic surveys performed annually along the coastlines of northern Oregon and southwestern Washington documented changes in beach and nearshore morphology between 2014 and 2019. Volume change analysis revealed measurable localized erosion and deposition throughout the study area, but significant net erosion at the regional scale (several kilometers [km]) was limited to BensonWorld’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 topographiMorphodynamic 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 (WashingtoByEcosystems, Natural Hazards, Water Resources, Coastal and Marine Hazards and Resources Program, Fisheries Program, Arizona Water Science Center, Pacific Coastal and Marine Science Center, Washington Water Science Center, Western Fisheries Research Center, Sediment Lab Suite and Carbon Analysis LaboratoryA regime shift in sediment export from a coastal watershed during a record wet winter, California: Implications for landscape response to hydroclimatic extremes
Small, steep watersheds are prolific sediment sources from which sediment flux is highly sensitive to climatic changes. Storm intensity and frequency are widely expected to increase during the 21st century, and so assessing the response of small, steep watersheds to extreme rainfall is essential to understanding landscape response to climate change. During record winter rainfall in 2016–2017, theInvestigation of input reduction techniques for morphodynamic modeling of complex inlets with baroclinic forcing
The Mouth of the Columbia River (MCR) is a complex estuary inlet system characterized by a buoyant plume created by high freshwater flows from the Columbia River into the Pacific Ocean. Data obtained during two major field campaigns have resulted in a comprehensive dataset of hydrodynamics and sediment transport under high (2013) and low (2005) river flow conditions. Through the analysis of this dIncreased sediment load during a large-scale dam removal changes nearshore subtidal communities
The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx—over 10 million tonnes—during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal communCoastal 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 million tonnes of sediment from river, coastal, and nearCoastal 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 rates of sand and gravel sediment transport in theLarge-scale dam removal on the Elwha River, Washington, USA: coastal geomorphic change
Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of mud, sand, and gravel since 1927, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams, initiated in September 2011, induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the geomoPre-USGS Publications
Stevens, A.W. , Wheatcroft, R.A., Wiberg, P.L., 2007, Seabed properties and sediment erodibility along the western Adriatic margin, Italy: Continental Shelf Research, v. 27, i. 3–4, pp. 400-416, doi: 10.1016/j.csr.2005.09.009Wheatcroft, R.A., Stevens, A.W., Hunt, L.M., Milligan, T.G., 2006, The large-scale distribution and internal geometry of the fall 2000 Po River flood deposit: Evidence from digital X-radiography: Continental Shelf Research, v. 26, i. 4, pp. 499-516, doi: 10.1016/j.csr.2006.01.002Borgeld, J.C., and A.W. Stevens, 2005, Humboldt Bay, California, surface sediments 2000-01, in Schlosser, S.C., and R. Rasmussen, eds., Proceedings of the Humboldt Bay symposium; Current perspectives on the physical and biological processes of Humboldt Bay, p. 51-64