Environmental Impact Research Program. Summary of Corps of Engineers Methodologies for Modeling Water Quality of Estuaries and Coastal Embayments

Abstract : Corps of Engineers engineering activities that produce changes in estuaries and coastal embayments primarily do so by altering the circulation; alterations in the circulation can affect the concentration of water quality constituents; and changes in water quality constituent concentrations may adversely affect organisms. This report summarizes capabilities for modeling water quality impacts of those Corps activities that can alter circulation and transport in estuarine and marine systems. Traditional waste load allocation models typically emphasize water quality kinetics while employing relatively coarse information on circulation. This report emphasizes the incorporation of accurate hydrodynamics either through coupling existing water quality models to hydrodynamic models or upgrading hydrodynamic models to include water quality. The proposed strategy for impact assessment is to first accurately investigate potential changes in circulation and transport. If no detectable changes occur, the chemical characteristics are assumed not to change. If however, a transport change is detected, then changes in water quality constituent concentrations should be examined through a water quality modeling study. Available numerical models are presented, and a basic numerical modeling procedure is discussed. (FR)