Hydrodynamic and water quality modeling in the tidal estuaries: The ribble estuary case

At the present time, ecological sustainability of water bodies has become a significant issue due to global climate change and increasing pollutant pressure. Anthropogenically different organic and inorganic pollutants can cause severe damages to natural life in water bodies. For this reason, over the course of many years, a lot of research have been carried out on the mathematical and physical expression of the transport of pollutants by hydrodynamic effects. The applications of Computational Fluid Dynamics, which is based on numerical solution methods with software technologies and started to be improved especially in the early 1950s, on environmental problems are increasing. Due to the flexibility it provides, Computational Fluid Dynamics supplants analytical and empirical solutions. Within the scope of the thesis, the propagation movement of fecal coliform bacteria, which is a pathogen indicator in the Ribble Estuary, where the tidal movement is dominant, was analyzed by using the Delft3D-FLOW and D-Water Quality programs, which are based on a Computational Fluid Dynamics. Spatial and temporal variations of water levels under tidal effect, velocity magnitudes and concentration of fecal coliform in the estuary were calculated. In addition, the performance of different mesh types, turbulence models and numerical solution methods in the calibration process are discussed. In the last part of the thesis, the effects and functionality of the different bathymetries obtained from the real measurements made in the field and satellite images on the results were evaluated. This study showed that thanks to the features provided by the programs used, different hydrodynamic mechanisms can be modeled for the propagation movement of many pollutants in water bodies.