EFDC

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.  The model website is at:  https://www.epa.gov/ceam/environmental-fluid-dynamics-code-efdc

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

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.