My research spans the multiple disciplines that converge in estuarine systems. Research projects include numerical model development, field observations of hydrodynamics and water quality, wetland and coastal vulnerability assessments, geomorphic change, and eutrophication.
In 2001, I began working for the USGS at the California Water Science Center, on the San Francisco Bay Sediment Transport Project with Dr. David Schoellhamer. In 2008 I moved to the Woods Hole Coastal and Marine Science Center and began multiple projects throughout the northeast US. The Estuarine Processes, Hazards, and Ecosystems project, started in 2015, details the past and ongoing studies we are involved with.
Professional Experience
2010-present: Research Oceanographer, Woods Hole Coastal and Marine Science Center
2008-2010: Hydraulic Engineer, Woods Hole Coastal and Marine Science Center
2001-2008: Hydraulic Engineer, California Water Science Center
Education and Certifications
I studied civil engineering at the University of Michigan (BSCE), the University of Florida (MSCE), and the University of California-Davis (Ph.D.).
Science and Products
Science to Support Marsh Conservation and Management Decisions in the Northeastern United States
Effects of Urban Coastal Armoring on Salt Marsh Sediment Supplies and Resilience to Climate Change
Coastal System Change at Fire Island, New York
Back-barrier and Estuarine - Coastal System Change at Fire Island, New York
Estuarine Processes, Hazards, and Ecosystems
Hurricane Sandy Response- Linking the Delmarva Peninsula's Geologic Framework to Coastal Vulnerability
Coastal Model Applications and Field Measurements
Estuarine Processes Tidal Wetlands
Estuarine Processes Tidal Wetlands
Estuarine Processes Tidal Wetlands
Estuarine Processes Tidal Wetlands
Lifespan of Massachusetts salt marsh units
Water quality data from a multiparameter sonde collected in the Herring River during November 2018 to November 2019 in Wellfleet, MA
Time-series measurements of oceanographic and water quality data collected in the Herring River, Wellfleet, Massachusetts, USA, November 2018 to November 2019
Aerial imagery and ground control points collected during an uncrewed aerial systems (UAS) survey at Plum Island Estuary and Parker River NWR (PIEPR), November 14, 2017 and March 28, 2019
Geospatial characterization of salt marshes on the Eastern Shore of Virginia
Lifespan of Chesapeake Bay salt marsh units
Geospatial characterization of salt marshes in Chesapeake Bay
Lifespan of marsh units in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
An Unvegetated to Vegetated Ratio (UVVR) for coastal wetlands of the Conterminous United States (2014-2018)
Suspended-sediment concentrations and loss-on-ignition from water samples collected in the Herring River during 2018-19 in Wellfleet, MA (ver 1.1, March 2023)
Climatological Wave Height, Wave Period and Wave Power along Coastal Areas of the East Coast of the United States and Gulf of Mexico
Tidal Datums, Tidal Range, and Nuisance Flooding Levels for Chesapeake Bay and Delaware Bay
Increased utilization of storm surge barriers: A research agenda on estuary impacts
Buzzards Bay salt marshes: Vulnerability and adaptation potential
Variability in marsh migration potential determined by topographic rather than anthropogenic constraints in the Chesapeake Bay region
Development and application of Landsat-based wetland vegetation cover and unvegetated-vegetated marsh ratio (UVVR) for the conterminous United States
Modeling the dynamics of salt marsh development in coastal land reclamation
How much marsh restoration is enough to deliver wave attenuation coastal protection benefits?
Modeling marsh dynamics using a 3-D coupled wave-flow-sediment model
Quantifying slopes as a driver of forest to marsh conversion using geospatial techniques: Application to Chesapeake Bay coastal-plain, USA
Sediment dynamics of a divergent bay–marsh complex
Development of a submerged aquatic vegetation growth model in the Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST v3.4) model
Applying cumulative effects to strategically advance large‐scale ecosystem restoration
Simulated estuary-wide response of seagrass (Zostera marina) to future scenarios of temperature and sea level
Non-USGS Publications**
(2016), Estimating time-dependent
connectivity in marine systems, Geophys.
Res. Lett., 43, doi:10.1002/2015GL066888.
**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.
COAWST Modeling System v3.4
National 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.
Science and Products
- Science
Science to Support Marsh Conservation and Management Decisions in the Northeastern United States
Coastal resource and infrastructure managers face rapidly mounting environmental challenges. Increases in sea levels, decaying or outdated infrastructure, compound flooding from ocean storm surges and river runoff, and temperature and moisture extremes are all increasing the vulnerability of natural habitats, public, private, and commercial infrastructure, and community health and functionality. TEffects of Urban Coastal Armoring on Salt Marsh Sediment Supplies and Resilience to Climate Change
Salt marshes are grassy wetlands that form along sheltered coastlines. These areas provide crucial habitats for many species of birds and other animals, in addition to recreational activities and economic opportunities. Marshes also protect the coast from storms and filter runoff from the landscape, ensuring cleaner and healthier coastal waters. As climate change causes sea levels to rise salt marCoastal System Change at Fire Island, New York
Fire Island is a 50-km long barrier island along the south shore of Long Island, New York. The island is comprised of seventeen year-round communities; federal, state, and county parks; and supports distinct ecosystems alongside areas of economic and cultural value. In addition to providing resources to its residents, the barrier island also protects the heavily-populated mainland from storm waves...Back-barrier and Estuarine - Coastal System Change at Fire Island, New York
Regional-scale modeling forecasts how atmospheric forcing and oceanographic circulation influence estuarine circulation and water levels, sediment transport, and wetland change.Estuarine Processes, Hazards, and Ecosystems
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...Hurricane Sandy Response- Linking the Delmarva Peninsula's Geologic Framework to Coastal Vulnerability
The Delmarva Peninsula is a 220-kilometer-long headland, spit, and barrier island complex that was significantly affected by Hurricane Sandy. In order to better constrain controls on coastal vulnerability and evolution, the region’s sediment sources, transport pathways and sediment sinks must be identified. This project defines the geologic framework of the Delmarva coastal system through...Coastal Model Applications and Field Measurements
Numerical models are used by scientists, engineers, coastal managers, and the public to understand and predict processes in the coastal ocean. This project supports the development and application of open-source coastal models and has several objectives: 1) improve the code of numerical sediment-transport models by implementing new or improved algorithms; 2) obtain measurements of coastal ocean...Estuarine 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.Estuarine 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.Estuarine 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.Estuarine 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. - Data
Filter Total Items: 52
Lifespan of Massachusetts salt marsh units
Lifespan of salt marshes in Massachusetts (MA) are calculated using conceptual marsh units defined by Ackerman and others (2022). The lifespan calculation is based on estimated sediment supply and sea-level rise (SLR) predictions after Ganju and others (2020). Sea level predictions are local estimates which correspond to the 0.3, 0.5, and 1.0 meter increase in Global Mean Sea Level (GMSL) scenarioWater quality data from a multiparameter sonde collected in the Herring River during November 2018 to November 2019 in Wellfleet, MA
Management efforts of the tidally-restricted Herring River in Wellfleet, MA include research to understand pre-restoration sediment conditions. Submerged multiparameter sondes that measure optical turbidity were deployed at four sites landward and seaward of the Herring River restriction. Periodically, the sites were visited and additional turbidity measurements were collected with a handheld multTime-series measurements of oceanographic and water quality data collected in the Herring River, Wellfleet, Massachusetts, USA, November 2018 to November 2019
Restoration in the tidally restricted Herring River Estuary in Wellfleet, MA benefits from understanding pre-restoration sediment transport conditions. Submerged sensors were deployed at four sites landward and seaward of the Herring River restriction to measure water velocity, water quality, water level, waves, and seabed elevation. These data will be used to evaluate sediment dynamics and geomorAerial imagery and ground control points collected during an uncrewed aerial systems (UAS) survey at Plum Island Estuary and Parker River NWR (PIEPR), November 14, 2017 and March 28, 2019
Low-altitude (80 and 100 meters above ground level) digital images were taken over an area of the Plum Island Estuary and Parker River National Wildlife Refuge (NWR) in Massachusetts using 3DR Solo unmanned aircraft systems (UAS) on November 14, 2017 and March 28, 2019. These images were collected as part of an effort to document marsh stability over time and quantify sediment movement using UAS tGeospatial characterization of salt marshes on the Eastern Shore of Virginia
This data release contains coastal wetland synthesis products for the Atlantic-facing Eastern Shore of Virginia (the data release for the Chesapeake Bay-facing portion of the Eastern Shore of Virginia is found here: https://doi.org/10.5066/P997EJYB). Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and tidal range are calculated for smaller units delineatedLifespan of Chesapeake Bay salt marsh units
Lifespan distribution in the Chesapeake Bay (CB) salt marsh complex is presented in terms of lifespan of conceptual marsh units defined by Ackerman and others (2022). The lifespan calculation is based on estimated sediment supply and sea-level rise (SLR) predictions after Ganju and others (2020). Sea level predictions are present day estimates at the prescribed rate of SLR, which correspond to theGeospatial characterization of salt marshes in Chesapeake Bay
This data release contains coastal wetland synthesis products for Chesapeake Bay. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and tidal range are calculated for smaller units delineated from a digital elevation model, providing the spatial variability of physical factors that influence wetland health. The U.S. Geological Survey has been expanding natioLifespan of marsh units in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
The sediment-based lifespan of salt marsh units in Assateague Island National Seashore (ASIS) and Chincoteague Bay is shown for conceptual marsh units defined by Defne and Ganju (2018). The lifespan represents the timescale by which the current sediment mass within a marsh parcel can no longer compensate for sediment export and deficits induced by sea-level rise. The lifespan calculation is basedAn Unvegetated to Vegetated Ratio (UVVR) for coastal wetlands of the Conterminous United States (2014-2018)
This USGS Data Release represents geospatial data sets which were created to produce an Unvegetated to Vegetated Ratio (UVVR) for coastal wetlands of the conterminous United States (2014-2018). The following listed image products were generated 1) Annual spatial datasets (rasters) from 2014 to 2018 each containing 4 bands (Band 1: Unvegetated land fraction; Band 2: Vegetated land fraction; Band 3:Suspended-sediment concentrations and loss-on-ignition from water samples collected in the Herring River during 2018-19 in Wellfleet, MA (ver 1.1, March 2023)
The Herring River in Wellfleet, MA is a tidally-restricted estuary system. Management options including potential restoration of unrestricted tidal flows require an understanding of pre-restoration sediment conditions. Altering future tidal flows may cause changes in net sediment flux and direction, which could affect marsh restoration and aquaculture in Wellfleet Harbor. This research aims to meaClimatological Wave Height, Wave Period and Wave Power along Coastal Areas of the East Coast of the United States and Gulf of Mexico
This U.S. Geological Survey data release provides data on spatial variations in climatological wave parameters (significant wave height, peak wave period, and wave power) for coastal areas along the United States East Coast and Gulf of Mexico. Significant wave height is the average wave height, from crest to trough, of the highest one-third of the waves in a specific time period. Peak wave periodTidal Datums, Tidal Range, and Nuisance Flooding Levels for Chesapeake Bay and Delaware Bay
This U.S. Geological Survey data release provides data on spatial variations in tidal datums, tidal range, and nuisance flooding in Chesapeake Bay and Delaware Bay. Tidal datums are standard elevations that are defined based on average tidal water levels. Datums are used as references to measure local water levels and to delineate regions in coastal environments. Nuisance flooding refers to the sp - Multimedia
- Publications
Filter Total Items: 103
Increased utilization of storm surge barriers: A research agenda on estuary impacts
Rising coastal flood risk and recent disasters are driving interest in the construction of gated storm surge barriers worldwide, with current studies recommending barriers for at least 11 estuaries in the United States alone. Surge barriers partially block estuary-ocean exchange with infrastructure across an estuary or its inlet and include gated areas that are closed only during flood events. TheAuthorsPhilip M. Orton, David K. Ralston, Bram C. van Prooijen, David Secor, Neil Kamal Ganju, Ziyu Chen, Sarah Fernald, Bennett Brooks, Kristin MarcellBuzzards Bay salt marshes: Vulnerability and adaptation potential
Salt marshes with lush grass meadows teeming with shorebirds are iconic features of the Buzzards Bay coast and provide opportunities for recreation, aesthetic enjoyment, as well as important environmental benefits. These productive coastal wetlands are important because they protect properties from storm surges, remove nutrients from the water and carbon from the atmosphere, and provide critical hAuthorsR. W Jakuba, A. Besterman, L. Hoffart, J. E. Costa, Neil Kamal Ganju, L. DeeganVariability in marsh migration potential determined by topographic rather than anthropogenic constraints in the Chesapeake Bay region
Sea level rise (SLR) and saltwater intrusion are driving inland shifts in coastal ecosystems. Here, we make high-resolution (1 m) predictions of land conversion under future SLR scenarios in 81 watersheds surrounding Chesapeake Bay, United States, a hotspot for accelerated SLR and saltwater intrusion. We find that 1050–3748 km2 of marsh could be created by 2100, largely at the expense of forestedAuthorsGrace Molino, Joel A. Carr, Neil Kamal Ganju, Matthew KirwanDevelopment and application of Landsat-based wetland vegetation cover and unvegetated-vegetated marsh ratio (UVVR) for the conterminous United States
Effective management and restoration of salt marshes and other vegetated intertidal habitats require objective and spatially integrated metrics of geomorphic status and vulnerability. The unvegetated-vegetated marsh ratio (UVVR), a recently developed metric, can be used to establish present-day vegetative cover, identify stability thresholds, and quantify vulnerability to open-water conversion oveAuthorsNeil Kamal Ganju, Brady Couvillion, Zafer Defne, Kate AckermanModeling the dynamics of salt marsh development in coastal land reclamation
The valuable ecosystem services of salt marshes are spurring marsh restoration projects around the world. However, it is difficult to determine the final vegetated area based on physical drivers. Herein, we use a 3D fully coupled vegetation-hydrodynamic-morphological modeling system (COAWST), to simulate the final vegetation cover and the timescale to reach it under various forcing conditions. MarAuthorsYiyang Xu, Tarandeep S. Kalra, Neil Kamal Ganju, Sergio FagherazziHow much marsh restoration is enough to deliver wave attenuation coastal protection benefits?
As coastal communities grow more vulnerable to sea-level rise and increased storminess, communities have turned to nature-based solutions to bolster coastal resilience and protection. Marshes have significant wave attenuation properties and can play an important role in coastal protection for many communities. Many restoration projects seek to maximize this ecosystem service but how much marsh resAuthorsKatherine A. Castagno, Neil Kamal Ganju, Michael W. Beck, Alison Bowden, Steven B. ScyphersModeling marsh dynamics using a 3-D coupled wave-flow-sediment model
Salt marshes are dynamic biogeomorphic systems that respond to external physical factors, including tides, sediment transport, and waves, as well as internal processes such as autochthonous soil formation. Predicting the fate of marshes requires a modeling framework that accounts for these processes in a coupled fashion. In this study, we implement two new marsh dynamic processes in the 3-D COAWSTAuthorsTarandeep S. Kalra, Neil Kamal Ganju, Alfredo Aretxabaleta, Joel A. Carr, Zafer Defne, Julia MoriartyQuantifying slopes as a driver of forest to marsh conversion using geospatial techniques: Application to Chesapeake Bay coastal-plain, USA
Coastal salt marshes, which provide valuable ecosystem services such as flood mitigation and carbon sequestration, are threatened by rising sea level. In response, these ecosystems migrate landward, converting available upland into salt marsh. In the coastal-plain surrounding Chesapeake Bay, United States, conversion of coastal forest to salt marsh is well-documented and may offset salt marsh lossAuthorsGrace Damore Molino, Zafer Defne, Alfredo Aretxabaleta, Neil Kamal Ganju, Joel A. CarrSediment 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 of fringing marshes: material released by marsh-edgAuthorsDaniel J. Nowacki, Neil Kamal GanjuDevelopment 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 nutrient cycling. To represent these dynamic proceAuthorsTarandeep S. Kalra, Neil Kamal Ganju, Jeremy M. TestaApplying cumulative effects to strategically advance large‐scale ecosystem restoration
International efforts to restore degraded ecosystems will continue to expand over the coming decades, yet the factors contributing to the effectiveness of long‐term restoration across large areas remain largely unexplored. At large scales, outcomes are more complex and synergistic than the additive impacts of individual restoration projects. Here, we propose a cumulative‐effects conceptual framewoAuthorsHeida L. Diefenderfer, Gregory Steyer, Matthew C. Harwell, Andrew J LoSchiavo, Hilary A. Neckles, David M. Burdick, Gary E. Johnson, Kate E. Buenau, Elene Trujillo, John C. Callaway, Ronald M. Thom, Neil Kamal Ganju, Robert R. TwilleySimulated 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-Little Egg Harbor (BB-LEH) in New Jersey, United States.AuthorsCara Scalpone, Jessie Jarvis, James Vasslides, Jeremy Testa, Neil Kamal GanjuNon-USGS Publications**
Defne, Z., N. K. Ganju, and A. Aretxabaleta
(2016), Estimating time-dependent
connectivity in marine systems, Geophys.
Res. Lett., 43, doi:10.1002/2015GL066888.Ganju, N. K., Brush, M. J., Rashleigh, B., Aretxabaleta, A. L., del Barrio, P., Grear, J. S., ... & Vaudrey, J. M., 2015, Progress and challenges in coupled hydrodynamic-ecological estuarine modeling, Estuaries and Coasts, 1-22.Ganju, N.K., Jaffe, B.E., and Schoellhamer, D.H., 2011, Discontinuous hindcast simulations of estuarine bathymetric change: a case study from Suisun Bay, California. Estuarine, Coastal and Shelf Science, 93, 142-150.Ganju, N.K., and Schoellhamer, D.H., 2006, Annual sediment flux estimates in a tidal strait using surrogate measurements. Estuarine, Coastal and Shelf Science, 69, 165-178.Ganju, N.K., Schoellhamer, D.H., and Jaffe, B.E., 2009, Hindcasting of decadal-timescale estuarine bathymetric change with a tidal-timescale model. Journal of Geophysical Research-Earth Surface, 114, F04019, doi:10.1029/2008JF001191.Ganju, N.K., Schoellhamer, D.H., Warner, J.C., Barad, M.F., and Schladow, S.G., 2004, Tidal oscillation of sediment between a river and a bay: a conceptual model. Estuarine, Coastal and Shelf Science, 60(1), 81-90.Ganju, N.K., and Sherwood, C.R., 2010, Effect of roughness formulation on the performance of a coupled wave, hydrodynamic, and sediment transport model. Ocean Modelling, 33, 299-313.Gartner, J.W., and Ganju, N.K., 2007, Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River. Limnology and Oceanography: Methods, 5, 156-162.Leonardi, N., Ganju, N.K. and Fagherazzi, S., 2016. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes. Proceedings of the National Academy of Sciences, 113(1), pp.64-68.Kirincich, A. R., Lentz, S. J., Farrar, J. T., and Ganju, N. K., 2013, The Spatial Structure of Tidal and Mean Circulation over the Inner Shelf South of Martha's Vineyard, Massachusetts. Journal of Physical Oceanography, 43(9).Miselis, J.L., Andrews, B.D., Nicholson, R.S., Defne, Z., Ganju, N.K. and Navoy, A., 2015. Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity. Estuaries and Coasts, pp.1-19.Oestreich, W. K., Ganju, N. K., Pohlman, J. W., and Suttles, S. E., 2016. Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation, Biogeosciences, 13, 583-595, doi:10.5194/bg-13-583-2016.Rosencranz, J.A., Ganju, N.K., Ambrose, R.F., Brosnahan, S.M., Dickhudt, P.J., Guntenspergen, G.R., MacDonald, G.M., Takekawa, J.Y, and Thorne, K.M., 2015, Balanced sediment fluxes in southern California’s Mediterranean-climate zone salt marshes, Estuaries and Coasts, DOI 10.1007/s12237-015-0056-y.**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.
- Software
COAWST Modeling System v3.4
Coupled ocean atmosphere wave sediment transport modeling system - News
- Web Tools
National 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.