## Ecosystems Research

WWQTCS Info
WWQTCS Home Technical Support Tools Watershed Models Basins LSPC WAMView SWMM WARMF Water Quality Models WASP QUAL2K Aquatox EPD-RIV1 Hydrodynamic Models EFDC EPD-RIV1 Database Training 

# Environmental Fluid Dynamics Code (EFDC)

The Environmental Fluid Dynamics Code (EFDC Hydro) 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 andCartesian or curvilinear, orthogonal horizontal coordinates to represent the physical characteristics of a waterbody. It solves threedimensional, vertically hydrostatic, free surface, turbulent averaged equations of motion for a variable-density fluid. Dynamicallycoupled 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's role in the TMDL Toolbox will be to provide necessary hydrodynamic inputs to WASP, the advanced receiving water quality model.
EFDC Preprocessor
In order to facilitate the setup and application of EFDC, a preprocessor is being developed. The preprocessor will be composed of two major components: the Curvilinear Grid Generator and the EFDC Model Interface. Together these components will enable users to generate curvilinear-orthogonal grids, simulate aquatic systems in 1, 2, or 3-dimensions, link 2-D grids to 1-D grids, quickly and easily set and change critical modeling parameters, and make use of watershed loading model results and monitoring data for boundary conditions.
The Curvilinear Grid Generator will enable a user to generate curvilinear-orthogonal grids that are required for the numerical model. It will significantly decrease the repetitive effort typically required through manual grid generation methods. Grid generation will be conducted interactively and intuitively through the interface and associated controls. Key features of the tool will include:

GIS interface Model domain designation through user control point designation Automatic insertion of grid boundary points based on control point designation Automatic curvilinear-orthogonal grid generation Model grid conversion to GIS shape file format Cell mapping between EFDC and WASP
Once a grid has been generated, it's necessary to set and calibrate pertinent modeling parameters. The EFDC interface will simplify the setup and application of EFDC through a user-friendly graphical interface and associated windows. It will support input of EFDC model run control and model parameter designation, and it will link directly to boundary condition/source data, e.g. watershed model output and point source contributions. Key features of the tool will include: http://www.epa.gov/athens/wwqtsc/html/efdc.html 

### Environmental Fluid Dynamics Code (EFDC) Page | Ecosystems Research | US EPA http://www.epa.gov/athens/wwqtsc/html/efdc.html

1 of 3 12/13/2011 2:16 PMDatabase-oriented interface

Visual linkage to the model grid Visual linkage to point and nonpoint source inputs New model parameter addition and accommodation Direct linkage to WRDB for boundary condition designation/generation

EFDC Model Information Current Version 1.0 Release Date July 9, 2002 Operating System Windows 95/98/ME/2000/XP Intended Audience Environmental Engineers/Scientists, Regulatory Agencies Key Words hydrodynamics, temperature, salinity, stratification NPS related, NPDES, point source(s), surface water, test/analysis, TMDL related Media Lakes, Rivers, Estuaries Pollutant Types hydrodynamic transport, links with Water Quality Analysis Simulation Program (WASP7)

File Type/Priority Filename/Format/Size File Description Install/Required EFDC-HYDRO.EXE (EXE)
-- Self Extracting Zip File

1 MB This file contains the EFDC

hydrodynamic model. Does not include the EFDC water quality components. Includes a 3-D example of rectangular cross section river. User is encouraged to download model documentation. Optional EFDC Manual
-- Zip File

538KB This file contains the EFDC-Hydro

Manual PDF in zip format.

Optional EFDC Fact Sheet-- (PDF, 2 pp., 764KB, about PDF) This file contains a Fact Sheet about the EFDC Modeling System in PDF Format. File Download Information

Technical Support Center fact sheet (PDF, 2 pp., 733 KB, about PDF)
TMDL fact sheet (PDF, 2 pp., 697 KB, about PDF) 

### Environmental Fluid Dynamics Code (EFDC) Page | Ecosystems Research | US EPA http://www.epa.gov/athens/wwqtsc/html/efdc.html

2 of 3 12/13/2011 2:16 PMWCMS

Last updated on Tuesday, November 01, 2011 

### Environmental Fluid Dynamics Code (EFDC) Page | Ecosystems Research | US EPA http://www.epa.gov/athens/wwqtsc/html/efdc.html

3 of 3 12/13/2011 2:16 PM