Numerical simulation of suspended sediment concentration in Lake Poyang during flood season considering dredging activities

Abstract

Numerical simulation and remote sensing are used in suspended sediment concentration simulation during flood season in Lake Poyang, in which water turbidity is highly affected by dredging activities. With the aid of Landsat ETM+ images, the location of main dredging areas and ships are detected. Several sediment point sources are added in dredging areas in the Delft3D model to simulate the suspended sediment concentration including the effects of dredging of Lake Poyang from July 1, 2011 to July 31, 2011.Taking in-situ data and suspended sediment concentration retrieved from MODIS images as validation data, there is a good consistence between the simulating and validating results, with R2 of 0.831, a root-mean-square error of 15.5 mg/L and a consistent spatial pattern of suspended sediment concentration compared with suspended sediment concentration retrieved from MODIS images. It also shows less dredging effects in the southern main lake and river inlets but more in the northern from channel in the west of Tangyin and the north of Songmen Mountain, water-way in the northern and the lake outlet, which is one of the main reasons causing high turbidity water in Lake Poyang. This study shows that by making good use of in-situ data and satellite remote sensing images, the precision of numerical simulation of suspended sediment concentration can be increased by considering the effect of human dredging activities, thus provided a good method for human affected water environment simulations of lakes.