Water quality simulation in reaches of Hanjiang River by 2D model

This paper presents an application of a two-dimensional depth-averaged flow-pollutant coupled model to the simulation of changes of water quality in some reaches of middle-downstream of the Hanjing River due to water transferring from the river. The 2D flow-pollutant coupled model incorporates the pollutant advection-dispersion equation into shallow water equations, which are solved simultaneously on an unstructured grid using finite volume method (FVM). The numerical flux in the normal direction to and across the interface of neighboring elements is estimated by using Osher type scheme, an approximate Riemann solver. Simulated water quality results have shown the effects of transferring water from the Danjiangkou Reservoir on the flow velocity field, pollution concentration and polluted area in the middle-downstream reaches of the Hanjiang river. The figures on flow velocity field and contours of pollutant COD in the river reaches are given in the paper.