Enhanced Propeller Wash Modeling for Mitigation of Sediment Resuspension in Port Environments
Building on previous foundational models, this study introduces an advanced EFDC+ simulation approach to predict and mitigate the environmental impacts of propeller wash in busy port areas. Newly incorporated mitigation strategies are designed to reduce sediment disturbance through operational modifications and engineered solutions.
Quantifying Model Output Uncertainty from Sparse Input Data: A Case Study in the Mississippi Sound and Mobile Bay
EFDC+ was used to develop a hydrodynamic-water quality model for the shallow Mississippi Sound and Mobile Bay estuaries, comparing four interpolation methods for augmenting sparse monthly input data into daily time series. Linear interpolation was the most preferred method due to its low RMSE and better agreement with observed data, while spline interpolation showed the least agreement.
Hydrological 0D and 2D Modelling of the Navío-Quebrado Coastal Lagoon (La Guajira, Colombia): A Challenging Exercise
After more than 1.5 years of observations from a simple monitoring system, a 0D hydrological model of the Navío-Quebrado coastal lagoon in La Guajira, Colombia was tested and compared against a more refined 2D hydrodynamic model. The exercise illuminates the behavior of the lagoon and identifies key points to improve in both monitoring and modelling.
Winter Water Quality Modelling Under Ice-Affected Conditions in Rivers and Lakes: A Comprehensive Review
This comprehensive review surveys water quality models used to study winter water quality in ice-affected rivers and lakes, focusing on their capabilities to simulate ice and its interaction with the aquatic environment. Seven models are reviewed — including EFDC/EFDC+ — alongside the challenges of ice-affected modelling and the need for greater emphasis on winter water quality data collection.
Potential Challenges for the Restoration of Biscayne Bay in the Face of Climate Change Effects Revealed with Predictive Models
A salinity transport model for Biscayne Bay, Florida was used to estimate salinity under scenarios of altered precipitation, increased temperature and ocean salinity, and sea level rise. Under the mildest scenario a 50% increase in baseline freshwater inputs is needed to maintain current bay salinities, rising to 300% under the worst case — suggesting current Everglades restoration efforts may be insufficient to even maintain present conditions.
Examining the Effect of Salinity on Dolphin Mortality Using Lagrangian Particle Tracking in a Hydrodynamic Model
An EFDC+ hydrodynamic model of the Mississippi Sound was used with Lagrangian particle tracking to hindcast the locations of bottlenose dolphin deaths during a 2019 unusual mortality event. Results indicate that most dolphins likely died west of their stranding locations, with simulated salinities well below five at their probable places of death — consistent with prolonged exposure to low-salinity waters following the opening of the Bonnet Carré Spillway.
Impacts of Freshwater Sources on Salinity Structure in a Large, Shallow Estuary
A hydrodynamic model was applied to Florida Bay to determine whether doubling Taylor River flow, as currently planned, is adequate to meet salinity performance measures and protect the bay's ecosystem. Rainfall — which supplies 45% of the bay's freshwater — caused the largest salinity reduction, and the restoration target was achieved more than 70% of the time only for existing bay conditions, not future sea-level rise.
Flood Risk Assessment of the Garita River in the Urban Zone of San Luis Potosí City, by Hydrodynamic Modeling
Numerical modeling with SWMM5, HEC-RAS, and EFDC Explorer was used to assess flood risk along the Garita Stream within the urban zone of San Luis Potosí City, Mexico. The 1D, 2D, and 3D simulations identified when the stream would overflow and which areas are most likely to flood across different return periods, supporting proposed mitigation solutions.
Sensitivity Analysis and Calibration of a Lagrangian Particle Tracking Module Using GPS-Tagged Drifters
The Lagrangian particle tracking module in EFDC+ was calibrated against six GPS-tagged drifters deployed by NOAA in the Mississippi Sound to track the movement of large floating marine carcasses. Adding wind drag raised the model Skill Score from 0.23 to 0.47, and the transition from a 2D to a 3D configuration had a larger effect than increasing vertical layers — though not enough to justify the added computational cost for long simulations.
Sensitivity Analysis of a Hydrodynamic and Harmful Algal Model in a Riverine System
A sensitivity analysis of the EFDC+ hydrodynamic and water quality model was conducted for simulating cyanobacteria growth — an important harmful algal bloom species — in the Ohio River, USA. Of 23 input parameters assessed across nine functional groups, light extinction parameters, maximum algal growth rate, and algal base metabolism were identified as the most sensitive for simulating algal growth.
Modeling Sediment Resuspension and Transport Processes Induced by Propeller Wash from Ship Traffic
A numerical modeling framework coupling propeller wash dynamics with EFDC+ was developed to predict sediment resuspension and transport from ship traffic. Validated against a US Navy field experiment, the model demonstrated that incorporating propeller-induced momentum significantly improves prediction of resuspended sediment distributions in both longitudinal and lateral directions.
Characterization of Salt Wedge Intrusion Process in a Geographically Complex Microtidal Deltaic Estuarine System
A three-dimensional EFDC+ Explorer model was implemented to analyze salt wedge intrusion in the Sinú River delta, Colombia, configured with dry- and wet-season field campaigns from 2021. The model showed river discharges above 319 m³/s prevent salt wedge intrusion, while critical low-discharge and sea level rise scenarios produced a maximum salt wedge reach of 7.40 km.
Seasonal Dynamics of Algal Net Primary Production in Response to Phosphorus Input in a Mesotrophic Subtropical Plateau Lake, Southwestern China
A comprehensive 3D hydrodynamic and eutrophication model with three functional phytoplankton groups was applied to simulate algal dynamics in Lake Erhai, a mesotrophic phosphorus-limited plateau lake in southwestern China. Modeled net primary production showed strong seasonal variation, with competition for phosphorus and temperature identified as the primary governing factors and high phytoplankton sensitivity to external total phosphorus reduction.
Water Quality Model-Based Methodology to Assess Assimilative Capacity of Wastewater Discharges in Rivers
Water quality monitoring and EFDC-based numerical simulation were used to evaluate the Sinú River's capacity to assimilate wastewater discharges in Colombia. Assimilative capacity was most affected when river flow was decreased by 50% while discharge concentrations and flows were increased fivefold, causing ammonia nitrogen, chemical oxygen demand, phosphates, and total nitrogen to exceed water quality reference limits.
Hydrodynamical Numerical Assessment of the Recent Droughts at Gallinas River, San Luis Potosí, Mexico
The EFDC model was calibrated and applied to investigate the causes of severe flow losses at the Gallinas River in San Luis Potosí, Mexico, where the downstream flow at the Tamul waterfall completely disappeared during the 2016–2020 dry seasons. The analysis concludes that the river's geology and geological configuration most likely generate the specific infiltrations driving the flow variations.
Modeling Sediment Transport in the Sinú River Delta, Colombia
Three-dimensional numerical simulations tracked the transport of fine sands, very fine sands, and coarse silts released by the Sinú River into the southern Caribbean Sea. Using the SedimentDrift Lagrangian framework forced with ERA-5 winds and CMEMS currents, the study analyzed how local hydrodynamics, morphology, and grain size determine sediment pathways from river mouth to seafloor.
Applying EFDC Explorer Model in the Gallinas River, Mexico to Estimate Its Assimilation Capacity for Water Quality Protection
The EFDC Explorer model was applied to the Gallinas River in Mexico's Huasteca Potosina region to determine its capacity to assimilate agricultural and industrial wastewater from sugar cane cultivation and processing. Simulations of phosphate, nitrate, and dissolved oxygen showed the river has good assimilation capacity thanks to reaeration processes that efficiently recover dissolved oxygen in the water column.
Mechanisms of Flood-Induced Levee Breaching in Marumori Town During the 2019 Hagibis Typhoon
Field observation and numerical simulation were used to investigate the flood characteristics and levee breaching mechanisms in Marumori Town during Typhoon Hagibis in October 2019. Most levee breaches were caused by water overflow at constriction areas, and a new levee breach criterion in terms of overflow depth and duration was proposed.
Monitoring an Ungauged Coastal Marsh to Analyze the Salinity Interaction of the Marsh with Lake Erie
An EFDC+ hydrodynamic model was developed for the ungauged Mentor Marsh of Ohio to simulate salinity distribution in a wetland that interacts with Lake Erie through a backwater effect. Calibration and validation against monitoring station data were good, and scenario analysis showed lake level rise drives a significant decrease in marsh salinity near Lake Erie.
Numerical Simulation of Phosphorus Release in an Urban Lake Based on a Diagenesis Model
A phosphorus diagenesis model was developed to simulate the dynamic release of phosphorus at the sediment–water interface of an urban lake. The model continuously describes phosphate flux at the interface, showing that sediment acts as a buffer that absorbs or releases phosphate to maintain balance — providing phosphate for algae growth over long periods even after large external loading reductions.
Predicting Cyanobacterial Harmful Algal Blooms (CyanoHABs) in a Regulated River Using a Revised EFDC Model
A revised EFDC model was developed to predict harmful cyanobacteria concentrations directly, rather than total chlorophyll-a, in the Nakdong River, South Korea. Modeling the Hapcheon-Changnyeong to Changnyeong-Haman Weir section for the May–October 2019 bloom season achieved 62% prediction accuracy using a five-step classification of harmful cyanobacteria levels.
Coupling of the AQUATOX and EFDC Models for Ecological Impact Assessment of Chemical Spill Scenarios in the Jeonju River, Korea
The proven ecological model AQUATOX was coupled with the hydrodynamic model EFDC to assess ecological damage from toluene spill scenarios in the Jeonju River, South Korea. A 21-day simulation of 30–30,000 kg leak scenarios showed significant ecological impact, with the greatest damage observed for the fish species group — the top predators.
Hydrodynamics and Water Quality Assessment of a Coastal Lagoon Using the Environmental Fluid Dynamics Code Explorer Modeling System
The EFDC Explorer Modeling System was implemented to determine the spatio-temporal distribution of temperature, dissolved oxygen, chemical oxygen demand, and nutrients in Ciénaga de Mallorquín, a RAMSAR-designated coastal lagoon in Colombia. The lagoon exhibited high productivity, with a Trophic State Index above 50 and temporal variation from mesotrophic to eutrophic conditions.
EFDC Domain Decomposition MPI-Based Implementation
This paper describes the MPI-based domain decomposition approach implemented in EFDC+, enabling it to run across large cluster systems and multi-core desktops with greater speed. For a large Chesapeake Bay model, the hybrid OMP/MPI version achieved a speedup of nearly 17 with 32 compute cores, and a strong scaling study on AWS reached a speedup of nearly 25 with 96 cores.
Analysis of Influence on Water Quality and Harmful Algal Blooms Due to Weir Gate Control in the Nakdong, Geum, and Yeongsan Rivers
A 3D hydrodynamic and water quality model was applied to evaluate how weir gate operations affect water quality and harmful algal bloom occurrences across three major Korean rivers. Open-gate scenarios reduced upstream chlorophyll-a and HABs in the Geum and Yeongsan Rivers but increased downstream concentrations, while the Nakdong River saw increases at all locations — reflecting the differing physical, chemical, and biological conditions at each site.
Estuarine Salinity Intrusion and Implications for Aquatic Habitat: A Case Study of the Lower St. Johns River Estuary, Florida
EFDC+ was applied to model the hydrodynamics of the Lower St. Johns River Estuary in Florida, analyzing the extent of salinity intrusion and its implications for aquatic habitat. Results showed salinity intrusion is primarily controlled by upstream flow, long-term open-ocean variations, and wind drag, with the habitat analysis establishing a baseline for evaluating future management scenarios.
Simulation of Nitrogen and Phosphorus Removal in an Ecological Ditch Based on the EFDC Model
An ecological ditch was designed and built as a pilot device to study nitrogen and phosphorus removal under the collaboration of aquatic organisms and hydraulic power. The transport and diffusion of N and P in the ditch was simulated with the three-dimensional EFDC water quality model, with average relative errors below 15% verifying the model's reliability.
Response Characteristics of the Perdido and Wolf Bay System to Inflows and Sea Level Rise
A three-dimensional EFDC model of the Perdido and Wolf Bay estuarine system in Alabama was used to analyze flow, salinity, and temperature distributions, calibrated against 2008–2009 field data (R² = 0.92 for water surface elevations). Using the concept of age of water, the study found ages ranging from under 20 days under high inflows to 160 days under low inflows, projected to increase by up to 60 days under sea level rise scenarios.
Developing an EFDC and Numerical Source-Apportionment Model for Nitrogen and Phosphorus Contribution Analysis in a Lake Basin
The Environmental Fluid Dynamic Code (EFDC) and a numerical source-apportionment model were applied to Lake Bali in Jiujiang City, China to predict the contributions of various pollution sources at any time and position. The calibrated model revealed strong spatial heterogeneity in how a pollution source affects lake water quality, providing useful information for optimizing pollution load reduction.
A Framework for Determining Improved Placement of Current Energy Converters Subject to Environmental Constraints
A modeling framework based on the Environmental Fluid Dynamics Code identifies deployment locations for current-energy-capture devices that maximize power output while minimizing environmental impacts. Over a 29-day period, an array layout ignoring environmental constraints extracted 19% more energy than the baseline, while a constraint-aware layout still extracted 16% more — demonstrating the framework's value for identifying improved field deployment layouts.
Relationship of the Thermal Stratification and Critical Flow Velocity Near the Baekje Weir in the Geum River
A three-dimensional EFDC+ hydrodynamic model with the Sigma-Zed vertical grid was used to investigate the relationship between flow velocity and thermal stability near the Baekje Weir in Korea's Geum River. The critical flow velocity that can avoid persistent thermal stratification was found to be approximately 0.1 m/s.
The Hydrodynamic Modelling for the Water Management of El Guájaro Reservoir, Colombia
A two-dimensional EFDC Explorer hydrodynamic model was implemented and calibrated for the Guájaro Reservoir in northern Colombia to assist sustainable operation of the Canal del Dique–Guájaro hydrosystem. Calibration against free surface levels and velocities across two climatic periods showed good agreement, with satisfactory Nash-Sutcliffe reliability results supporting restoration and water supply decisions.
Two-Dimensional Numerical Modelling of Sediment and Chemical Constituent Transport Within the Lower Reaches of the Athabasca River
A two-dimensional EFDC model was used to investigate flows and the transport of cohesive sediment and associated chemical constituents — polycyclic aromatic hydrocarbons and metals — in the lower Athabasca River between Fort McMurray and Embarrass Airport. Results show floodplains, back channels, and islands are the major areas of concern for deposition, with constituent outflows depending heavily on river bed concentration levels.
Hydrodynamics Modelling Utilizing the EFDC Explorer Model for the Sustainable Management of the Canal del Dique–Guájaro Hydrosystem, Colombia
A two-dimensional EFDC Explorer hydrodynamic model was implemented and calibrated for the Canal del Dique–Guájaro hydrosystem in northern Colombia to support sustainable management of the reservoir. Comparisons of measured and simulated free surface levels and velocities across two climatic periods showed good agreement, with satisfactory Nash-Sutcliffe reliability results.
Sediment Transport and Metals Modeling in an Urban Stream — The Don River, Toronto
A 1D EFDC model of the lower Don River in Toronto was coupled with the PCSWMM urban watershed model to simulate hydrodynamics, sediment transport, and the fate and transport of copper, lead, and zinc. The EFDC model better predicted measured suspended sediment and metals loads than PCSWMM alone, highlighting the importance of simulating instream physical processes.
Design and Deployment of a Dynamic-Coupling Tool for EFDC
A dynamic-coupling tool was developed to link several geographically adjacent EFDC hydrodynamic models, transferring time-series data at their common boundaries using the Message Passing Interface. Applied to a three-model test case on a Linux cluster, the tool achieved a speedup of 8.53 over a sequential Windows run by optimizing Intel Fortran compiler flags.
Numerical Simulation of Flow Dynamics in a Tidal River Under Various Upstream Hydrologic Conditions
A three-dimensional Environmental Fluid Dynamics Code model was developed for a 17-km segment of the Mobile River, Alabama, forced by upstream river inflows, downstream tides, and atmospheric conditions. Calibrated against 2011 field data with Nash-Sutcliffe coefficients above 0.94 for water levels, the model revealed that flow recirculation occurs only under small inflows when downstream tides control the flow pattern.
Analysis of Water Temperature of Laguna Lake Using the EFDC Model
The Environmental Fluid Dynamics Code was used to characterize the water temperature of Laguna Lake, a widely used freshwater source in Metropolitan Manila. The lake was found to be thermally unstratified, with an average depth of 3.21 m and mean temperatures ranging from 25 to 29 °C, and the model is positioned for future linkage with the Water Quality Analysis Simulation Program (WASP).
Sigma-ZED: A Computationally Efficient Approach to Reduce the Horizontal Gradient Error in EFDC's Vertical Sigma Grid
A new vertical layering approach, Sigma-ZED, was developed and applied to the EFDC model to reduce the pressure gradient errors inherent in the standard vertical sigma grid. By allowing the number of layers to vary over the model domain, the approach is more computationally efficient than a comparable sigma stretch grid and more accurately reproduces vertical temperature variation and thermal stratification.
A Coupled Modeling Approach to Predict Water Quality in Lake Taihu, China: Linkage to Climate Change Projections
A coupled hydrodynamic-water quality-sediment flux model was used to assess how environmental variables in Lake Taihu, China respond to climate change scenarios projected under RCP 8.5. Results showed annual average water temperature increasing by up to 3.2 °C by the 2080s, earlier and longer thermal stratification, increased sediment flux, decreased dissolved oxygen, and algal blooms advancing roughly six days per decade.
Modeling Residual Circulation and Stratification in the Oujiang River Estuary
A three-dimensional hydrodynamic model was applied to the Oujiang River estuary in China to investigate residual circulation and stratification patterns. The study examines how river discharge and tidal forcing interact to shape circulation in this estuarine system.
Three-Dimensional Modeling of Sediment Transport in the Wuhan Catchments of the Yangtze River
A three-dimensional flow-sediment model of the Wuhan portion of the Yangtze River was developed with EFDC to study the changing riverbed. Simulations of the high water period indicated erosion as the main issue, with maximum erosion of 0.27 m at the banks of Tian Xingzhou, and suspended sediment concentrations increasing from the left bank to the right bank at the Han Kou Hydrologic Station section.
Field and Modelling Investigations of Fresh-Water Plume Behaviour in Response to Infrequent High-Precipitation Events, Sydney Estuary, Australia
A verified Environmental Fluid Dynamics Code model was combined with measured salinity and rainfall data to investigate the relationship between catchment rainfall and freshwater plume behaviour in the Sydney Estuary, Australia. The study concluded that because the monitored freshwater plume broke down within the estuary, stormwater contaminants from high-precipitation events were retained in the system longer than previously recognised.
Modeling Water Ages and Thermal Structure of Lake Mead Under Changing Water Levels
The 3D hydrodynamic Environmental Fluid Dynamics Code (EFDC) was used to model water age and thermal structure of Lake Mead under high-stage and low-stage water level scenarios. Results show water level drawdown plays an important role in thermal stratification and water movement, with the largest impacts in shallow regions such as Las Vegas Bay.
Influence of Physical Forcing on Bottom-Water Dissolved Oxygen within Caloosahatchee River Estuary, Florida
EFDC was applied to simulate dissolved oxygen, salinity, water temperature, and nutrients in the Caloosahatchee River Estuary, Florida. Sensitivity analyses identified river discharge, wind, and tidal forcing as the primary drivers of spatial and temporal DO distributions — with wind-driven mixing increasing bottom-layer DO and river discharge enhancing stratification in deeper areas of the estuary.