EFDC

EFDC (Environmental Fluid Dynamics Code)

Criterion	Explanation
General Description	The Environmental Fluid Dynamics Code (EFDC) is a multifunctional surface water modeling system, which includes hydrodynamic, sediment-contaminant, and eutrophication components. EFDC has been applied to over 100 water bodies including rivers, lakes, reservoirs, wetlands, estuaries, and coastal ocean regions in support of environmental assessment and management and regulatory requirements.
Model Domain	The model domain is flexible and can be specified by the user, and can include coastal, estuarine, lakes and river areas.
Developer	Developed by John Hamrick at Virginia Institute of Marine Science; Tetra Tech developed, maintained, and supported EFDC from 1996 - 2007 with support from the EPA
Hardware computing requirements	Windows, Sun, Unix
Code language	FORTRAN
Original application	Chesapeake Bay estuary, other estuary and wetland systems; power plant cooling water discharge
Public/proprietary and cost	Model and source code are in the public domain. Available at: https://www.epa.gov/ceam/environment-fluid-dynamics-code-efdc-download-page
Physically or empirically based	Physically based
Mathematical methods used	Finite difference; solves three-dimensional, vertically hydrostatic, free surface, turbulent averaged equations of motion for a variable-density fluid. Dynamically-coupled transport equations for turbulent kinetic energy, turbulent length scale, salinity and temperature are also solved.
Input data requirements	Input data includes: Domain (grid parameters, bathymetry) Initial conditions (water level, salinity, water temperature, pollutant and sediment concentrations) Boundary conditions (inflows, outflows, water level, salinity, water temperature, pollutant and sediment concentrations) Physical parameters (describing constants, viscosity, heat flux, sediment, tidal forces) Environmental parameters (precipitation, evaporation, wind speed and direction)
Outputs	The model outputs a variety of array file formats for three-dimensional vector and scalar field visualization. Model outputs include: Water level, flow volume and direction, salinity, water temperature, water quality (pollutant, sediment) concentrations.
Pre-processing and post-processing tools	A third-party GUI developed by Dynamic Solutions-International, LLC (DSI) is available for pre- and post-processing.
Representation of uncertainty	Uncertainty analysis is not integrated into the modeling framework
Prevalence	Broad use in US and abroad; was part of EPA's TMDL Toolbox; no longer supported by EPA
Ease of use for public entities	The third-party GUI developed by Dynamic Solutions-International, LLC (DSI) would be required for training and set-up, otherwise the time required to set up the model would be extensive.
Ease of obtaining information and availability of technical support	DSI has created a pre, post processor and GUI for EFDC through a subscription-based service. The company offers training and other user resources.
Source code availability	The source code is available for modification if needed.
Status of model development	Last release by EPA September 2007; DSI continues to develop and support model for a fee.
Challenges in integration	As part of the EPA's TMDL toolbox, EFDC was tailored to integrate with watershed models. Because EFDC and the TMDL toolbox are no longer supported by the EPA, some challenge may exist in obtaining the most up to date source code and documentation.