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Model Report

Environmental Fluid Dynamics Code

Last Revision Date: 11/16/2009 View as PDF
General Information Back to Top
Model Abbreviated Name:

EFDC
Model Extended Name:

Environmental Fluid Dynamics Code
Model Overview/Abstract:
The Environmental Fluid Dynamics Code (EFDC)is a state-of-the-art hydrodynamic model that can be used to simulate aquatic systems in one, two, and three dimensions. It has evolved over the past two decades to become one of the most widely used and technically defensible hydrodynamic models in the world. EFDC uses stretched or sigma vertical coordinates and Cartesian or curvilinear, orthogonal horizontal coordinates to represent the physical characteristics of a waterbody. It 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. The EFDC model allows for drying and wetting in shallow areas by a mass conservation scheme. The physics of the EFDC model and many aspects of the computational scheme are equivalent to the widely used Blumberg-Mellor model and U.S. Army Corps of Engineers' Chesapeake Bay model. EFDC will provide necessary hydrodynamic inputs to WASP, the advanced receiving water quality model.
Keywords:
Model Technical Contact Information:
Tim Wool
U.S. EPA ORD/NERL-ERD
Watershed and Water Quality Modeling Technical Support Center
Athens, GA
wool.tim@epa.gov
706-355-8312
Model Homepage: http://www.epa.gov/athens/wwqtsc

User Information Back to Top
Technical Requirements
Computer Hardware
Standard Desktop System. Higher performance machine maybe need for large simulations.
Compatible Operating Systems
Windows 95 or higher
UNIX
Linux
Macintosh
Other Software Required to Run the Model
FORTRAN Compiler to change dimensions of model. Executable included in distribution should work for most applications.
Download Information
The EFDC model is available to be downloaded.
Using the Model
Basic Model Inputs
EFDC uses stretched or sigma vertical coordinates and Cartesian or curvilinear, orthogonal horizontal coordinates to represent the physical characteristics of a waterbody. It 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. The EFDC model allows for drying and wetting in shallow areas by a mass conservation scheme.

Waterbody broken up into computational grid, forcing functions such as: flow, water surface elevation, meteorological data and initial conditions. More complex the application the greater the input requirements.

Basic Model Outputs
User selects the output variables from the model. All model output can be viewed using a graphical/tabular post processor that is included with the WASP6 model. It is easy to take results from EFDC to other models or other software for analysis and/or publication.
User Support
User's Guide Available?
Watershed and Water Quality Modeling Technical Support Center maintains an EFDC Users Manual and is included with the installation package. The Users Manual is periodically updated as the model is enhanced.

Model Science Back to Top
Summary of Model Structure and Methods
Model predicts water movement in complex waterbodies. Water movement is based upon flow, water surface elevation and density gradients.

Governing equations are solved numerically, both in space and time.

Model Evaluation
EFDC has been tested against analytical solutions, and has been peer reviewed for work done on Superfund Sites. The model has an application history that spans the last 10 years and is used routinely in the US and world.


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