Software Development for Surface Water Quality Modeling

In the past decades, the modeling of surface water systems, including estuaries, coastal region, rivers, and lakes, has made great progress. There have been a variety of successful simulations of hydrodynamics, water quality, sediment transport and toxicant transport. However, the complexities of performing multi-dimensional and time-dependent modeling have hindered their widespread use. The complexities are often derived from labor-intensive, time-consuming, and error-prone procedures that may or may not directly associated with the modeling analysis itself, such as the requirement and processing of large quantity of input data, grid making, input file setup, and generating and viewing 3D and time-dependent model results.

The purpose of this study is to develop a user-friendly and intuitive software package for surface water system modeling and water quality management. The package includes four major modules: 1) the window-based Environmental Fluid Dynamics Code (EFDC), 2) a grid generator, 3) an Oracle database, and 4) a graphic package.

The window-based EFDC model is the central module of this software package. The model comprises a three-dimensional surface water modeling system for hydrodynamic, water quality and sediment-contaminant simulations of rivers, lakes, reservoirs, wetland systems, estuaries, and coastal ocean. The model has seven prognostic hydrodynamic variables, a coupled twenty state variable water column eutrophication model with a twenty six state variable sediment biogeochemical processes model, and an unlimited number of sediment and toxic contaminant variables. Through windows and online help system, the tasks of model setup, debugging, and model calibration are made much easier.

The window-based grid generator is designed to reduce the labor-intensive work of grid making for 3D models. The Oracle Database is constructed to archive model parameters, measured data, model results, and environmental management information. The graphic package is built for making graphics and for animations.

All modules of the software systems are designed in object-oriented approach and are documented in the United Modeling Language. Considering platform independent requirement and potential internet application in the future, the software is implemented in Java language. It is believed that this software package will be an useful tool for the modeling of hydrodynamics, water quality, sediment transport, and toxicant fate and transport in surface water systems.