Abstract:

In order to obtain the evolution of erosiondeposition in the Yangtze River Estuary,the synthesizing analysis method based on the time series analysis of sediment quantity of scoursilt,correlation analysis of the amount of upstream sediment and sediment quantity of scoursilt,drift analysis of the middle sandbank and typical crosssection analysis was put forward using the dataprocessing and spatial analyzing of geographical information system (GIS).This synthesizing analysis method was targeted to the zoning of foreshore landforms and the middle sandbank of the Yangtze River Estuary,and quantitatively analyzed the change of erosiondeposition in different time periods.The year of 1991,2001 and 2008 were selected to analyze the topographic evolution of the major sandbanks in the upside of south branch of the Yangtze River Estuary,based on the analysis of whole series of actually measured data.As a whole,in Chongming tidal flat,southern branch,southern channel,northern channel,Nanhui tidal flat and Jiuduan sandbank,the erosion effect played a dominant role in the recent years.Deposition was the key trend in Chongming northern branch and Hengsha tidal flat.The erosion in southern branch of the Yangtze River Estuary was serious and the major sandbanks in southern branch were all moved to the southwest.It indicates that the change of annual sediment discharge and the annual suspended sediment concentration of the Yangtze River into the sea is one of the important factors in the evolution of erosiondeposition in the middle sandbanks of the Yangtze River Estuary.