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Project Abstract

This proposal is to develop a robust, efficient, mechanistic based watershed numerical model for ecosystem modeling, that is comprised of river/stream, overland, and saturated/unsatureated subsurface media and accounts for hydrodynamic, sediment transport, pollutant transport, fate and transformation.  The model will be highly modularized and adapted to high performance computing environments.  The model will be linked to several user-friendly platforms of modeling environment.

The objectives are in response to EPA ecological research strategies (EPA, 1998) to provide the first principle-based modeling tools for: 1) understanding, quantifying, and modeling key transport and transformation mechanisms of physical, chemical, and biological processes, 2) developing an integrated modeling system for high priority problems of interest (EPA, 1998) including sediments, nutrients, industrial chemicals, pesticides, metals, algae, and microbes, and 3) providing a prototype modeling framework for the EPA covering a full range of computing architectures from personal computers to scalable, parallel machines.

To achieve the above objectives, the approach taken is to conduct four research tasks.  The first is to enhance the robustness and accuracy of WASH123D (Yeh et al, 1998).  The second is to link to visualization/user interfaces of several selected modeling environments such as GMS, BASIN, ARGUS, etc.  The third is to port the model to high performance computing under several hardware architectures.  Finally, the fourth is to verify and validate each module in the modeling software with experimental data and, the complete model will be validated with field data from the watersheds located in the Mid Atlantic region.

The significance (expected results) of the research is three fold.  First, it enables us to move beyond past piecemeal approaches and creates an integrated approach needed to facilitate the evolution toward more comprehensive assessment tools.  Second it is in line with EPA's goal that requires future models "to be based as closely as possible on first principle" and "sufficiently complex in their description of the understanding processes that they become virtual realities" (EPA, 1998).  Third, the numerical software will be instrumental in: providing exposure concentrations from multiple stressors at multiple scales, aiding in the selection of indicators and designs of a monitoring network, and providing a physics-based tool fro watershed assessment.  Furthermore, WASH123D will provide a mechanistic-based TMDL input for lakes/reservoirs and tidal water bodies.
 

References

EPA, 1998. Ecological Research Strategy.  EPA/800/R-98/086.  U. S. Environmental Protection Agency, Office of Research and Development, Washington, DC 20460.

Yeh, G. T., H. P. Cheng, J. R. Cheng, and Jerry H. Lin, 1998.  A Numerical Model to Simulate Water Flow and Contaminant and Sediment Transport in Watershed Systems of 1-D Stream-River Network, 2-D Overland Regime, and 3-D Subsurface Media (WASH123D: Version 1.0). Technical Report CHL-98-19. Waterway Experiment Station, U. S. Army Corps of Engineering, Vicksburg, MS 39180-6199.