A two-dimensional numerical model of water quality for the Jiao(ling) River Estuary

The diversion and expansion of the Jiao(ling) River sluice constitutes major hydraulic engineering in Zhejiang Province. The completion of the project will change the hydrological condition of the Jiao(ling) River Estuary to a certain extent, consequently affecting the water quality of the estuary. This study constructed a two-dimensional numerical model of water quality for the Jiao(ling) River based on measured topographic and hydrological water quality data. The domain of the model extended to the sea area in the river mouth and was used to simulate the dilution and mixing of pollutants after entering the sea area. The model obtained reasonable water quality concentrations of estuarine flood tide inflow. Therefore, the model was able to resolve the previous challenge of identifying the flood water quality boundary resulting from setting the downstream boundary in a modelled river. Model validation showed that the model was able to reflect the changes in hydrodynamic forces and water quality concentrations of the Jiao River under the combined action of tidal current and runoff.