Enhanced Fluid Dyanmics Computer Code (EFDC) and Water Quality Analsyis Simulation Package (WASP) Model Development

Started: 4th Quarter 2004
 Completed: June 2006

Description:
The goal of this family of tasks is to enhance the Environmental Fluid Dynamics Computer Code (EFDC) and Water Quality Analysis Simulation Package (WASP) models for use in the Savannah River and Harbor. EFDC and WASP code was developed for the Savannah River and Harbor by EPA, Region IV, for their Dissolved Oxygen TMDL work and is the starting point for this effort. Under contract, the code will be enhanced by use of a finer model grid used to represent the river and estuary, updating the bathymetric data used by the model and revising the calculation of river-marsh interactions.

Status:
The calibration report for the H&S model and the Dissolved Oxygen models has been reviewed by the Federal agencies comprising the SMART and by the states of GA and SC, as well as the City of Savannah. Links to the calibration report and the agency letters are posted below. The Federal Cooperating Agencies (USACE, EPA, USFWS, and NMFS) decided on May 21, 2004 during an Executive Management Group meeting that the Dissolved Oxygen model developed by GPA's contractor (Applied Technology & Managment) was not defensible in its delivered configuration due to the vertical mixing formulation that was employed. This formulation was site specific and was originally developed in the modeling for the Feasibility Study in the 1997-1998 timeframe. It had been carried over to the GRS modeling effort without modification. Upon review, the Federal agencies declined to accept the model for use in the Savannah Harbor Expansion Project.

EPA had commissioned the adaptation of two other models for use in setting Total Maximum Daily Load (TMDL) requirements for the Savannah River, rather than waiting for the models being developed for the Savannah Harbor Expansion Project as had been planned in 1998. This decision was driven by EPA's court mandate to release draft limits in August 2004. The Federal agencies decided to invest the available time and resources into the refinement of these models for use for the evaluation of impacts for the Savannah Harbor Expansion Project and defer further refinement of the models developed by GPA. Those models, EFDC (Environmental Fluid Dynamics Code) (hydrodynamic & salinity) and WASP (Dissolved Oxygen or Water Quality) are public domain models that are supported by EPA's research arm and have history of application to other evaluations.

The Savannah District has assumed responsibility for development of both EFDC and WASP for use in the Savannah Harbor Expansion Project. They are developing the contracting requirements and documents for this effort. Their goal is to initiate the development in late summer 2004 and to have both models ready for agency evaluation early in 2005.  The Savannah District is also working to put into place an effective and efficient organization and communications for development and review of both models.

The EFDC and WASP7 models have been refined by Tetra Tech under contract to the Savannah District, USACE. Both models have had refinements made in the areas of modeling grid resolution and configuration, boundary conditions, bathymetry, channel roughness, and marsh representation. The WASP model has had refinements made unique to water quality projections, including BOD rates. Additional quality control related review of calibration data collected in 1997 and 1999 has been done to screen for anomalies and correct for instrumentation bias or drift. Analysis of the uncertainty of the original TMDL version of the models was conducted and refinements incorporated resulting from that analysis into the SHEP EFDC and WASP7 models.  Analysis of caibration data collected for use in the calibration of the WASP7 model was requested by EPA and is being conducted by USGS. The technical need for additional uncertainty or perturbation analysis as recommended by Kinetic Analysis Corporation, is being evaluated by the agencies collaborating on the model calibrations - USACE, EPA, USGS, USFWS, NMFS, GA EPD, and SCDHEC.

 Links: