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Andrew Stevens

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 2004

  • Humboldt State University, Arcata, CA
    B.S., Oceanography, May 2002 (with honors)

Science and Products

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Illustration showing an oblique view of the Puget Sound watershed.

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.
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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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.
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USGS science for a changing world logo

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
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Community for Data Integration (CDI)
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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
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Filter Total Items: 31

Bathymetry data and sediment transport modeling of a submerged nearshore berm at the mouth of the Columbia River, Oregon and Washington, 2020-2021

This data release contains gridded bathymetry data from repeated multibeam sonar surveys and input files for a hydrodynamic and sediment transport model application of the mouth of the Columbia River (MCR), Oregon and Washington. The bathymetry data were collected by the U.S. Army Corps of Engineers Portland District Surveys Section between September 9, 2020, and March 10, 2021, to characterize th
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Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, Sediment Lab Suite and Carbon Analysis Laboratory

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Pacific Coastal and Marine Science Center

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
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Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
Filter Total Items: 32
Four photos show scientists working in the field collecting data using various methods.
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Two people on personal watercraft maneuver separately and spaced apart in a beach setting near a jetty.
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Bald eagle sits atop a leafless tree, overlooking a marshy inlet with farmland in the distance.
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Photographic panorama showing the San Lorenzo river flowing wide and muddy into the ocean, past the Santa Cruz Beach Boardwalk.
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two young men standing on a pier with a large tripod, looking down at camera, and holding equipment.
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two men standing in a boat tied up to a dock
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person standing up riding a personal watercraft across small ocean swells, with buildings and a long pier in the background
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man walking along wet sand on beach wearing a backpack with an antenna sticking pout of it
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a person stands on a rocky beach wearing sunglasses and a backpack with an antenna.
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USGS scientist Jackson Currie navigates a personal water craft through waves, collecting bathymetric data in Monterey, CA
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Cars, pedestrians, and homes alongside a coast with big waves hitting the cliffs and sections of the cliff have collapsed.
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View from above looking down on a person sitting on a jet ski in the water.
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Sunset along a rocky coastline with a person riding a jet ski in the water.
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A four-wheel off-road vehicle is driven along the beach with calm waves.
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A woman walks in ankle-high water wearing a PFD and backpack with equipment in it.
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Man walks along the beach wearing a backpack and is looking at a small computer in his hand.
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Photograph of Moss Landing beach with power plant smoke stacks in distance, man wearing GPS equipment, and pelicans and seagulls
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Pelicans and seagulls stand on beach looking disinterested, while a man nearby walks along the beach toward the water.
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USGS all-terrain vehicle is equipped with GPS and collects beach topography on Rio Del Mar State Beach, Aptos, CA
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Gentle river waters near grassy cliff in foreground, with a beach, and an amusement park in background, other buildings afar.
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Smiling man wearing safety gear, standing up on personal watercraft moving through the water, giving the thumb's-up sign.
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Filter Total Items: 29

Assessment of vulnerabilities and opportunities to restore marsh sediment supply at Nisqually River Delta, west-central Washington

A cascading set of hazards to coastal environments is intimately tied to sediment transport and includes the flooding and erosion of shorelines and habitats that support communities, industry, infrastructure, and ecosystem functions (for example, habitats critical to fisheries). This report summarizes modeling and measurement data used to evaluate the sediment budget of the Nisqually River Delta,
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Pacific Coastal and Marine Science Center

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
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Coastal and Marine Hazards and Resources Program, Astrogeology Science Center, Pacific Coastal and Marine Science Center

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

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Natural Hazards, Coastal and Marine Hazards and Resources Program, Mendenhall Research Fellowship Program, Pacific Coastal and Marine Science Center

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
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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

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Ecosystems, Natural Hazards, Water Resources, Coastal and Marine Hazards and Resources Program, Fisheries Program (unpublished), 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
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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
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Ecosystems, Natural Hazards, Coastal and Marine Hazards and Resources Program, Fisheries Program (unpublished), Pacific Coastal and Marine Science Center, Western Fisheries Research Center

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
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Ecosystems, Coastal and Marine Hazards and Resources Program, Species Management Research Program, Pacific Coastal and Marine Science Center, Western Fisheries Research Center

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
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Non-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

**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