Neil Kamal Ganju, PhD
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
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
Idealized COAWST numerical model for testing marsh wave thrust and lateral retreat dynamics routines
COAWST model of Barnegat Bay creeks to demonstrate marsh dynamics
Unvegetated to vegetated marsh ratio in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
Geospatial Characterization of Salt Marshes for Massachusetts
Wave thrust values at point locations along the shorelines of Massachusetts and Rhode Island
Wave thrust values at point locations along the shorelines of Chesapeake Bay, Maryland and Virginia
Discharge measurements made in Bayou Heron and Bayou Middle, Grand Bay, Mississippi in January 2017
Coastal wetlands of the Blackwater region, Chesapeake Bay, Maryland
Geochemical data supporting investigation of solute and particle cycling and fluxes from two tidal wetlands on the south shore of Cape Cod, Massachusetts, 2012-19 (ver. 2.0, October 2022)
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
Sediment delivery to marsh platforms minimized by source decoupling and flux convergence
Sediment budget estimates for a highly impacted embayment with extensive wetland loss
A non-linear relationship between marsh size and sediment trapping capacity compromises salt marshes’ resilience to sea-level rise
Representing the function and sensitivity of coastal interfaces in Earth system models
Spatiotemporal variability of light attenuation and net ecosystem metabolism in a back-barrier estuary
Determining the drivers of suspended sediment dynamics in tidal marsh-influenced estuaries using high-resolution ocean color remote sensing
A geospatially resolved wetland vulnerability index: Synthesis of physical drivers
Are elevation and open-water conversion of salt marshes connected?
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.
Science and Products
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Filter Total Items: 58
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 spIdealized COAWST numerical model for testing marsh wave thrust and lateral retreat dynamics routines
There are two idealized domains developed in this work to test the marsh dynamics in the COAWST modeling framework. 1. First idealized domain is to test and verify the lateral thrust calculations. 2. Second idealized domain is to test the implementation of lateral retreat formulations.COAWST model of Barnegat Bay creeks to demonstrate marsh dynamics
The COAWST (Coupled Ocean-Atmosphere-Wave-Sediment Transport) modeling framework was extended to add two key processes that affect marshes, erosion due to lateral wave thrust (LWT) and vertical accretion due to biomass productivity. The testing of the combined effects of integrating these two processes was done by modeling marsh complexes within Forsythe National Wildlife Refuge and the Barnegat BUnvegetated to vegetated marsh ratio in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
Unvegetated to vegetated marsh ratio (UVVR) in the Assateague Island National Seashore and Chincoteague Bay is computed based on conceptual marsh units defined by Defne and Ganju (2018). UVVR was calculated based on U.S. Department of Agriculture National Agriculture Imagery Program (NAIP) 1-meter resolution imagery. Through scientific efforts initiated with the Hurricane Sandy Science Plan, the UGeospatial Characterization of Salt Marshes for Massachusetts
This data release contains coastal wetland synthesis products for Massachusetts. 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 nationWave thrust values at point locations along the shorelines of Massachusetts and Rhode Island
This product provides spatial variations in wave thrust along shorelines in Massachusetts and Rhode Island. Natural features of relevance along the State coast are salt marshes. In recent times, marshes have been eroding primarily through lateral erosion. Wave thrust represents a metric of wave attack acting on marsh edges. The wave thrust is calculated as the vertical integral of the dynamic presWave thrust values at point locations along the shorelines of Chesapeake Bay, Maryland and Virginia
This product provides spatial variations in wave thrust along shorelines in the Chesapeake Bay. Natural features of relevance along the Bay coast are salt marshes. In recent times, marshes have been eroding primarily through lateral erosion. Wave thrust represents a metric of wave attack acting on marsh edges. The wave thrust is calculated as the vertical integral of the dynamic pressure of waves.Discharge measurements made in Bayou Heron and Bayou Middle, Grand Bay, Mississippi in January 2017
Grand Bay, a 30-square-kilometer embayment of the Gulf of Mexico bordered by 20 square kilometers of salt marsh, is experiencing rapid lateral shoreline erosion at up to 5 meters per year. Determining whether the eroded sediment is exported to the deep ocean or imported via tidal channels and deposited on the marsh platform is critical to understanding the long-term response of the marsh to wave aCoastal wetlands of the Blackwater region, 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. The U.S.Geochemical data supporting investigation of solute and particle cycling and fluxes from two tidal wetlands on the south shore of Cape Cod, Massachusetts, 2012-19 (ver. 2.0, October 2022)
Assessment of geochemical cycling within tidal wetlands and measurement of fluxes of dissolved and particulate constituents between wetlands and coastal water bodies are critical to evaluating ecosystem function, service, and status. The U.S. Geological Survey and collaborators collected surface water and porewater geochemical data from a tidal wetland located on the eastern shore of Sage Lot Pond - Multimedia
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Filter Total Items: 107
Sediment 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 K. 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 K. 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 K. 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 K. GanjuSediment 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 individual tidal cycles. Here, we use an array of oAuthorsDaniel Coleman, Neil K. Ganju, Matthew KirwanSediment 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 measurement and modeling technologies. We used two indepenAuthorsRobert Chant, David K. Ralston, Neil K. Ganju, Casia Pianca, Amy Simonson, Richard CartwrightA 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 marshes themselves. We conducted a meta-analysis of sAuthorsCarmine Donatelli, Xiaohe Zhang, Neil K. Ganju, Alfredo Aretxabaleta, Sergio Fagherazzi, Nicoletta LeonardiRepresenting the function and sensitivity of coastal interfaces in Earth system models
Along coastal interfaces, components of the Earth system interact to regulate ecosystem functions and Earth’s climate. Between the land and ocean, diverse coastal ecosystem types transform, store, and transport material. A dynamic two-way exchange of energy and matter is driven by hydrological and marine processes such as river and groundwater discharge, tides, waves, and storms. Global models lacAuthorsNicholas Ward, J. Patrick Megonigal, Ben Bond-Lamberty, Vanessa Bailey, David Butman, Elizabeth Canuel, Heida Diefenderfer, Neil K. Ganju, Miguel Goni, Emily B. Graham, Charles Hopkinson, Tarang Khangaonkar, Adam Langley, Nate McDowell, Allison Myers-Pigg, Rebecca Neumann, Christopher Osburn, Rene Price, Joel Rowland, Aditi Sengupta, Marc Simard, Peter E. Thornton, Maria Tzortziou, Rodrigo Vargas, Pamela Weisenhorn, Lisamarie Windham-MyersSpatiotemporal variability of light attenuation and net ecosystem metabolism in a back-barrier estuary
Quantifying system-wide biogeochemical dynamics and ecosystem metabolism in estuaries is often attempted using a long-term continuous record at a single site or short-term records at multiple sites due to sampling limitations that preclude long-term monitoring. However, differences in the dominant primary producer at a given location (e.g., phytoplankton versus benthic producers) control diel variAuthorsNeil Kamal Ganju, Jeremy Testa, Steven E. Suttles, Alfredo AretxabaletaDetermining 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 are driven by a complex and often site-specific inteAuthorsXiaohe Zhang, Cedric Fichot, Carly Baracco, Ruizhe Guo, Sydney Neugebauer, Zachary Bengtsson, Neil K. Ganju, Sergio FagherazziA 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/biophysical features. The geospatial data are based onAuthorsZafer Defne, Alfredo Aretxabaleta, Neil K. Ganju, Tarandeep S. Kalra, Daniel Jones, Kathryn SmithAre elevation and open-water conversion of salt marshes connected?
Salt marsh assessments focus on vertical metrics such as accretion or lateral metrics such as open-water conversion, without exploration of how the dimensions are related. We exploited a novel geospatial dataset to explore how elevation is related to the unvegetated-vegetated marsh ratio (UVVR), a lateral metric, across individual marsh “units” within four estuarine-marsh systems. We find that eleAuthorsNeil K. Ganju, Zafer Defne, Sergio FagherazziNon-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.
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