Estuarine Processes, Hazards, and Ecosystems
Coastal Wetland Synthesis Products
At the U.S. Geological Survey's Woods Hole Coastal and Marine Science Center we undertake interdisciplinary projects that aim to quantify and understand estuarine processes through observations and numerical modeling.
Download DataHydrodynamic Model Simulations
A collection of hydrodynamic model simulations, their inputs, outputs by USGS Woods Hole Coastal and Marine Science Center. For more information on the Coupled Ocean Atmospheric Wave Sediment Transport (COAWST) modeling system.
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Estuarine processes, hazards, and ecosystems describes several interdisciplinary projects that aim to quantify and understand estuarine processes through observations and numerical modeling.
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Estuarine processes, hazards, and ecosystems describes several interdisciplinary projects that aim to quantify and understand estuarine processes through observations and numerical modeling. Both the spatial and temporal scales of these mechanisms are important, and therefore require modern instrumentation and state-of-the-art hydrodynamic models. These projects are led from the U.S. Geological Survey's Woods Hole Coastal and Marine Science Center, but are collaborative projects that include participation from other U.S. Geological Survey offices, other federal and state agencies, and academic institutions.
Estuaries are dynamic environments where complex interactions between the atmosphere, ocean, watershed, ecosystems, and human infrastructure take place. They serve as valuable ecological habitat and provide numerous ecosystem services and recreational opportunities. However, they are modified by physical processes such as storms and sea-level rise, while anthropogenic impacts such as nutrient loading threaten ecosystem function within estuaries. This project collects basic observational data on these processes, develops numerical models of the processes, and applies the models to understand the past, present, and future states of estuaries.
Measuring parameters such as water velocity, salinity, sediment concentration, dissolved oxygen and other constituents in watersheds, tidal wetlands, estuaries, and coasts is critical for evaluating the socioeconomic and ecological function of those regions. Technological advances have made it possible to autonomously measure these parameters over timescales of weeks to months. These measurements are necessary to evaluate three-dimensional numerical models that can represent the spatial and temporal complexity of these parameters. Once the models adequately represent relevant aspects of the physical system, they can be used to evaluate possible future scenarios including sea-level rise, streamflow changes, land-use modifications, and geomorphic evolution.
Estuarine Processes Model Development
We are developing new routines within the COAWST model framework to represent coupled bio-physical processes in estuarine and coastal regions. These include routines for marsh vulnerability to waves, estuarine biogeochemistry, and feedbacks between aquatic vegetation and hydrodynamics.
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Date published: March 1, 2020Status: ActiveMorphologic changes from sound-side inundation of North Core Banks, NC during Hurricane Dorian
Morphologic changes from sound-side inundation of North Core Banks, Cape Lookout National Seashore, North Carolina, during Hurricane Dorian
Contacts: Christopher Sherwood, PhD -
Date published: February 21, 2019Status: ActiveEstuarine Processes, Hazards, and Ecosystems-Study Sites
Estuaries are dynamic environments where complex interactions between the atmosphere, ocean, watershed, ecosystems, and human infrastructure take place. They serve as valuable ecological habitat and provide numerous ecosystem services and recreational opportunities. However, they are modified by physical processes such as storms and sea-level rise, while anthropogenic impacts such as nutrient...
Contacts: Neil Kamal Ganju, PhD -
Date published: March 5, 2018Status: ActiveEstuarine Processes Eutrophication
Increased loadings of nutrients to estuaries have altered ecosystem function by encouraging growth of phytoplankton and macroalgae while inducing large swings in dissolved oxygen and threatening the sustainability of seagrass meadows. We are measuring and modeling these processes to understand the future trajectory of estuarine ecosystems.
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Date published: March 5, 2018Status: ActiveEstuarine Processes Tidal Wetlands
Tidal wetlands are an important geomorphic and ecological feature of the coastal zone. Our projects deal with the physical forcings that affect wetland stability over event-to-annual timescales, including wave attack, sediment supply, and sea-level rise.
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Date published: March 5, 2018Status: ActiveEstuarine Processes Coastal Hazards
Extreme tides and coastal storms transfer high water levels to estuaries through natural and managed entrances. The size of the transfer depends on the duration of the event and the geomorphology of the estuary. We use observational data and modeling scenarios to understand and spatially map this transfer at our study sites.
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Date published: March 5, 2018Status: ActiveEstuarine Processes Geomorphic Change
Changes to the geomorphic structure of estuaries impact hydrodynamics, ecosystem function, and navigation. We are implementing new methods of observing and modeling these changes using innovative field and computational approaches.
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Year Published: 2021Sediment dynamics of a divergent bay–marsh complex
Bay–marsh systems, composed of an embayment surrounded by fringing marsh incised by tidal channels, are widely distributed coastal environments. External sediment availability, marsh-edge erosion, and sea-level rise acting on such bay–marsh complexes may drive diverse sediment-flux regimes. These factors reinforce the ephemeral and dynamic nature...
Nowacki, Daniel J. ; Ganju, Neil Kamal
Sediment budget estimates for a highly impacted embayment with extensive wetland loss
External sediment supply is an important control on wetland morphology and vulnerability to storms, sea-level rise, and land use change. Constraining sediment supply and net budgets is difficult due to multiple timescales of variability in hydrodynamic forcing and suspended-sediment concentrations, as well as the fundamental limitations of...
Chant, Robert; Ralston, David K.; Ganju, Neil Kamal; Pianca, Casia; Simonson, Amy; Cartwright, Richard Development of a submerged aquatic vegetation growth model in the Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST v3.4) model
The coupled biophysical interactions between submerged aquatic vegetation (SAV), hydrodynamics (currents and waves), sediment dynamics, and nutrient cycling have long been of interest in estuarine environments. Recent observational studies have addressed feedbacks between SAV meadows and their role in modifying current velocity, sedimentation, and...
Kalra, Tarandeep S.; Ganju, Neil Kamal; Testa, Jeremy M. Simulated estuary-wide response of seagrass (Zostera marina) to future scenarios of temperature and sea level
Seagrass communities are a vital component of estuarine ecosystems, but are threatened by projected sea level rise (SLR) and temperature increases with climate change. To understand these potential effects, we developed a spatially explicit model that represents seagrass (Zostera marina) habitat and estuary-wide productivity for Barnegat Bay-...
Scalpone, Cara; Jarvis, Jessie; Vasslides, James; Testa, Jeremy; Ganju, Neil Kamal Dynamics of marsh-derived sediments in lagoon-type estuaries
Salt marshes are valuable ecosystems that must trap sediments and accrete in order to counteract the deleterious effect of sea‐level rise. Previous studies have shown that the capacity of marshes to build up vertically depends on both autogenous and exogenous processes including eco‐geomorphic feedbacks and sediment supply from in‐land and coastal...
Donatelli, Carmine; Kalra, Tarandeep S.; Fagherazzi, Sergio; Zhang, Xoaohe; Leonardi, Nicoletta Sediment delivery to marsh platforms minimized by source decoupling and flux convergence
Sediment supply is a primary factor in determining marsh response to sea level rise and is typically approximated through high‐resolution measurements of suspended sediment concentrations (SSCs) from adjacent tidal channels. However, understanding sediment transport across the marsh itself remains limited by discontinuous measurements of SSC over...
Coleman, Daniel; Ganju, Neil Kamal; Kirwan, Matthew A non-linear relationship between marsh size and sediment trapping capacity compromises salt marshes’ resilience to sea-level rise
Global assessments predict the impact of sea-level rise on salt marshes with present-day levels of sediment supply from rivers and the coastal ocean. However, these assessments do not consider that variations in marsh extent and the related reconfiguration of intertidal area affect local sediment dynamics, ultimately controlling the fate of the...
Donatelli, Carmine; Zhang, Xiaohe; Ganju, Neil Kamal; Aretxabaleta, Alfredo; Fagherazzi, Sergio; Leonardi, Nicoletta Sediment transport in a restored, river-influenced Pacific Northwest estuary
Predicting the success of future investments in coastal and estuarine ecosystem restorations is limited by scarce data quantifying sediment budgets and transport processes of prior restorations. This study provides detailed analyses of the hydrodynamics and sediment fluxes of a recently restored U.S. Pacific Northwest estuary, a 61 ha former...
Nowacki, Daniel J. ; Grossman, Eric E. Determining the drivers of suspended sediment dynamics in tidal marsh-influenced estuaries using high-resolution ocean color remote sensing
Sediment budgets are a critical metric to assess coastal marsh vulnerability to sea-level rise and declining riverine sediment inputs. However, calculating accurate sediment budgets is challenging in tidal marsh-influenced estuaries where suspended sediment concentrations (SSC) typically vary on scales of hours and meters, and where SSC dynamics...
Zhang, Xiaohe; Fichot, Cedric; Baracco, Carly; Guo, Ruizhe; Neugebauer, Sydney; Bengtsson, Zachary; Ganju, Neil Kamal; Fagherazzi, Sergio A geospatially resolved wetland vulnerability index: Synthesis of physical drivers
Assessing wetland vulnerability to chronic and episodic physical drivers is fundamental for establishing restoration priorities. We synthesized multiple data sets from E.B Forsythe National Wildlife Refuge, New Jersey, to establish a wetland vulnerability metric that integrates a range of physical processes, regulatory information and physical/...
Defne, Zafer; Aretxabaleta, Alfredo; Ganju, Neil Kamal; Kalra, Tarandeep S.; Jones, Daniel K.; Smith, Kathryn Simple metrics predict salt-marsh sediment fluxes
The growth (or decay) of salt marshes depends on suspended-sediment flux into and out of the marsh. Suspended-sediment concentration (SSC) is a key element of the flux, and SSC-based metrics reflect the long-term sediment-flux trajectories of a variety of salt marshes. One metric, the flood–ebb SSC differential, correlates with area-normalized...
Nowacki, Daniel J. ; Ganju, Neil Kamal Hydrodynamic and morphologic response of a back-barrier estuary to an extratropical storm
We investigated the hydrodynamic and morphologic response of Barnegat Bay-Little Egg Harbor, New Jersey, USA to Hurricane Sandy. We implemented a three-dimensional, coupled ocean-wave-sediment transport model of the estuary and explored the role of offshore water levels, offshore waves, local winds and waves by systematically removing forcings...
Defne, Zafer; Ganju, Neil Kamal; Moriarty, Julia M. Spatial distribution of water level impact to back-barrier bays
Water level in semi-enclosed bays, landward of barrier islands, is mainly driven by offshore sea level fluctuations that are modulated by bay geometry and bathymetry, causing spatial variability in the ensuing response (transfer). Local wind setup can have a secondary role that depends on wind speed, fetch, and relative orientation of the wind...
Aretxabaleta, Alfredo; Ganju, Neil Kamal; Defne, Zafer; Signell, Richard P.
U.S. Geological Survey Oceanographic Time-Series Data Collection
Oceanographic time-series measurements made by the U.S. Geological Survey between 1975 and the present as part of research programs. The data were collected to address specific research questions and were primarily collected over durations less than a year, using stationary platforms, with sensors near the sea floor. These data have been used to study of ocean dynamics and to validate ocean...
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Date published: May 24, 2021Coastal Wetlands of Blackwater salt marsh complex, Chesapeake Bay, Maryland
This data release contains coastal wetland synthesis products for the geographic region of Blackwater, Chesapeake Bay, Maryland. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and others, are calculated for smaller units delineated from a digital elevation model, providing the spatial variability of physical factors that influence wetland health.
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Date published: December 8, 2020U.S. Geological Survey Hydrodynamic Model Simulations
A collection of hydrodynamic model simulations, their inputs, outputs by USGS Woods Hole Coastal and Marine Science Center. For more information on the Coupled Ocean Atmospheric Wave Sediment Transport (COAWST) modeling system see https://code.usgs.gov/coawstmodel/COAWST.
Attribution: Woods Hole Coastal and Marine Science Center -
Date published: July 21, 2020Coastal wetlands of Hudson Valley and New York City, New York
This data release contains coastal wetland synthesis products for the geographic region of Hudson Valley and New York City, New York. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and mean tidal range, are calculated for smaller units delineated from a Digital Elevation Model, providing the spatial variability of physical factors that influence...
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Date published: June 2, 2020Coastal wetlands of north shore Long Island, New York
This data release contains coastal wetland synthesis products for the geographic region of north shore Long Island, New York. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and mean tidal range, are calculated for smaller units delineated from a Digital Elevation Model, providing the spatial variability of physical factors that influence wetland...
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Date published: June 2, 2020Slope Values Across Marsh-Forest Boundary in Chesapeake Bay Region, USA
The marsh-forest boundary in the Chesapeake Bay was determined by geoprocessing high-resolution (1 square meter) land use and land cover data sets. Perpendicular transects were cast at standard intervals (30 meters) along the boundary within a GIS by repurposing the...
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Date published: March 31, 2020Coastal wetlands of eastern Long Island, New York
This data release contains coastal wetland synthesis products for the geographic region of eastern Long Island, New York, including the north and south forks, Gardiners Island, and Fishers Island. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and mean tidal range, are calculated for smaller units delineated from a Digital Elevation Model.
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Date published: November 26, 2019U.S. Geological Survey hydrodynamic model simulations for Barnegat Bay, New Jersey, during Hurricane Sandy, 2012
We used the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST; Warner and others, 2010) model to simulate ocean circulation, waves, and sediment transport in Barnegat Bay, New Jersey, during Hurricane Sandy. The simulation period was from October 27 to November 4, 2012. We used a 2012 digital terrain model (Andrews and others, 2015) to prescribe the prestorm bathymetry.
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Date published: August 21, 2019Coastal wetlands from Jamaica Bay to western Great South Bay, New York
This data release contains coastal wetland synthesis products for the geographic region from Jamaica Bay to western Great South Bay, located in southeastern New York State. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and mean tidal range, are calculated for smaller units delineated from a Digital Elevation Model.
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Date published: March 12, 2019Conceptual marsh units for Cape Cod National Seashore salt marsh complex, Massachusetts
The salt marsh complex of Cape Cod National Seashore (CACO), Massachusetts, USA and approximal wetlands were delineated to smaller, conceptual marsh units by geoprocessing of surface elevation data. Flow accumulation based on the relative elevation of each location is used to determine the ridge lines that separate each marsh unit
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Date published: March 12, 2019
Unvegetated to vegetated marsh ratio in Cape Cod National Seashore salt marsh complex, Massachusetts
Unvegetated to vegetated marsh ratio (UVVR) in the Cape Cod National Seashore (CACO) salt marsh complex and approximal wetlands is computed based on conceptual marsh units defined by Defne and Ganju (2019). UVVR was calculated based on U.S. Department of Agriculture National Agriculture Imagery Program (NAIP) 1-meter resolution imagery.
Coastal Wetlands: The State and Future of a Precious Resource
Coastal wetlands, and salt marshes specifically, are simultaneously geomorphic and biologic systems. They proliferate across a narrow range of elevation, water level, and salinity conditions. Salt marshes rely on their own growth and sediment input to maintain or increase their extent, whereas physical forces such as waves and sea-level rise tend to reduce it.
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Date published: May 20, 2021National UVVR Map
This map shows the unvegetated and vegetated area of coastal wetlands and adjacent land (inland and shorelines) for the Conterminous United States computed from 2014-2018 Landsat imagery at ~30 meter horizontal resolution.
Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System
The Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System is an agglomeration of open-source modeling components that has been tailored to investigate coupled processes of the atmosphere, ocean, and waves in the coastal ocean.
Scientific Research in Great South Bay, NY
Steve Suttles and Neil Ganju surveying the position of a deployed oceanographic platform in Great South Bay, NY
Preparing oceanographic platform in Forsythe NWR, NJ
Neil Ganju (standing) and Patrick Dickhudt preparing an oceanographic platform to measure wetland sediment transport in Forsythe NWR, New Jersey
Collecting Samples in Barnegat Bay
Box-cores provide a relatively undistributed look into the recent past to help better understand the processes contributing to sediment deposition and erosion.
Barnegat Bay, NJ Surface Sediments
Surface sediments will be analyzed for various physical parameters that will be used as initial conditions in hydrodynamic and sediment transport models.
Storm erosion at Chincoteague Bay, MD
Storm induced erosion of marsh shorelines can provide significant quantities of sediment to the bay altering the deposition patterns.
Measuring seagrass!
Measuring seagrass biomass in Chincoteague Bay, Maryland to constrain numerical models.
Flood tidal shoal
Flood tidal shoal at Barnegat Inlet, New Jersey (courtesy USGS EROS NAIP orthophotography)
Barnegat Bay, NJ sunset
Sunset over Barnegat Bay and Forsythe National Wildlife Refuge, New Jersey
Eye of the storm!
Satellite image of Hurricane Sandy (courtesy NASA GOES http://weather.msfc.nasa.gov/GOES/)
Macroalgae, seagrass, and litter oh my!
Macroalgae, seagrass, and litter in West Falmouth Harbor, MA
Focus on Estuaries and Coastal Wetlands
Estuaries and wetlands provide a critical defense against storms and sea-level rise while providing economically valuable services. How well they protect coastal communities and host diverse ecosystems is largely a function of their shape (morphology), which is controlled by factors such as sediment movement and biological feedbacks.