| This dissertation presents a comprehensive system for the modeling of hydrodynamics and ecological properties of the river systems, with emphasis on the abilities to simulate water temperature, water quality, aquatic ecology, contaminant transport, and aquatic ecotoxicology. The model is designed to deal with a long term prediction in environmental properties of the ecosystems. The framework of the integrated model is composed of four submodels: (1) water temperature model, (2) water quality and aquatic ecological model, (3) contaminant fate and transport model, and (4) aquatic ecotoxicological model. These submodels are integrated into the existing hydrodynamic and sediment transport model, CCHE1D.;The water temperature model is capable of simulating the heat transfer based on the law of conservation of energy. The water quality and ecological model is designed to incorporate the modeling of water quality and food web dynamics. Water quality model alone can be used for the modeling of non-conservative substance, biological oxygen demand, dissolved oxygen, nitrogen, and phosphorus. The food web structure consists of phytoplankton, zooplankton, forage fish, and predatory fish. The age-structure model is not considered in this study for simplicity.;The contaminant fate and transport model accounts for the water and suspended- sediment phase transports with equilibrium partitioning, volatilization, biodegradation, advection, dispersion, uptake and depuration due to biota. Direct uptake from water, consumption of contaminated food, and depuration of contaminant are considered in the bioaccumulation model.;The water temperature, water quality, and aquatic ecology models have been applied to predict ecological properties of the Tualatin River, Oregon. The model has been used to simulate water quality and food web dynamics of the Lower Boise River, Idaho. A number of wastewater treatment plants, tributaries, and flow withdrawal stations are located along the rivers. The model predicts the instream water quality variations due to the loadings from the lateral discharges and seasonal fluctuations.;The ecotoxicological model has been applied to predict the PCB accumulation in biotic organisms of the Upper Hudson River, New York. Long term simulated results of nutrients, biomass concentrations of aquatic organisms, and total PCB concentrations are in agreement with the measurements. |
