Sensibility of Delta Forward Coastal Response to Decrease in Riverine Sediment Supply:A Case Study from the Seaward Coast of the Chongming Island in the Changjiang River Delta

Based on analysis of topographic data surveyed between 1977 and 2004 in the subaqueous delta on the seaward side of the Chongming Island in the Changjiang River Delta with ArcGIS software,and data of remote sensing and measurement of elevation in the intertidal area within the same region,this paper deals with the sensibility of delta response to decrease in riverine sediment supply.The results show that as a whole the progradation rate of the study area went down with the decrease of sediment supply from the Changjiang River in time scales longer than a decade.However,the response was complicated because of the marine hydrodynamics and evolution of local shoal-channel systems,and reverse trends could be found in some shorter periods and subareas.On the basis of these findings,the future evolution of the study area was forecasted for the coming decades.