Environmental Fluid Dynamics Code (EFDC) Model Overview
The Environmental Fluid Dynamics Code (EFDC) is a general-purpose modeling package for simulating three‑dimensional (3-D) flow, transport, and biogeochemical processes in surface water systems including: rivers, lakes, estuaries, reservoirs, wetlands, and near-shore to shelf-scale coastal regions. The EFDC model was originally developed by John Hamrick at the Virginia Institute of Marine Science for estuarine and coastal applications and is public domain software (Hamrick, 1992). The US EPA has continued to support its development and now EFDC is part of a family of models recommended by EPA for TMDL development. In addition to hydrodynamic and salinity and temperature transport simulation capabilities, EFDC is capable of simulating cohesive and non-cohesive sediment transport, near-field and far-field discharge dilution from multiple sources, the transport and fate of toxic contaminants in the water and sediment phases, and the dissolved oxygen/nutrient process (i.e. eutrophication). Special enhancements to the hydrodynamics of the code, including vegetation resistance, drying and wetting, hydraulic structure representation, wave‑current boundary layer interaction, and wave-induced currents, allow refined modeling of wetland and marsh systems, controlled-flow systems, and near-shore wave-induced currents and sediment transport. The EFDC code has been extensively tested and documented and used in more than 80 modeling studies. The code is currently used by university, government, and engineering and environmental consulting organizations.
Dynamic Solutions-International, LLC (DSI), has developed a version of the code that streamlines the modeling process and links to DSI’s pre- and post-processing tools. For a detailed overview of the following features of EFDC you are referred to our EFDC_DSI summary document.
Toxic Contaminant Transport and Fate
Wetland, Marsh, and Tidal Flat Simulation Extension
Near-shore Wave-Induced Currents and Sediment Transport Extensions
The DSI version of EFDC (EFDC_DSI) has a number of enhancements to aide model development and application. The following summarize the main enhancements:
- Dynamic memory allocation. This allows the user to use the same executable between modeling applications without having to always recompile the EFDC source code. Helps prevent inadvertent errors and provides more traceability for the source code.
- Enhanced heat exchange options utilizing equilibrium temperatures for the water/atmosphere interface and spatially variable bed temperatures, coupled to the Water Quality Model.
- Streamlining of the code for quicker run times.
- Customized linkage of model results to the pre/post processor.
- Ability to customize the linkage of any 2D/3D EFDC variable to the post processing tools.
- Lagrangian Particle Tracking.
- Internal Windwave generation.
- Marine Hydro-kinetics (MHK) module from Sandia National Labs EFDC to assist with the effects of operating turbines and wave energy converters in waterbodies.
EFDC_DSI is included in the WEB, FULL and TRIAL versions of EFDC_Explorer as an executable program. EFDC_DSI is open source and the source code is available to users of EFDC_Explorer FULL version and clients upon request from DSI. It should be noted that EFDC_DSI is a single-threaded version of EFDC. It is optimized for Intel FORTRAN and availalbe in two versions, one for Windows and one for Linux. For a list of other recent enhancements to the EFDC_Explorer/ EFDC_DSI modeling system, please see here.
DSI have now also developed a multithreaded version of EFDC, called EFDC_DSI_OMP, with the following features:
- Significantly faster run times, proportional to the number of processors being used.
- User specification of number of cores utilized.
EFDC_DSI_OMP source code is not available except upon special request and at the discretion of DSI.
DSI also work with the US Environmental Protection Agency (EPA) to provide ongoing updates and enhancements to both DSI’s version of EFDC as well as the version provided by EPA (click to download EFDC_EPA source code).