COASTAL EROSION OF THE YANGTZE ESTUARY

The Yangtze delta is an alluvial delta which has sediment discharge from the Yangtze River deposit in. For a long time, it has been in the process of deposition due to the great deal of sediment from the Yangtze River. However, since the mid of last century, the situation of deposition-erosion of the Yangtze estuary has been changed with the strengthening coastal erosion in China. The decrease in sediment discharge plays an important role under the influence of human activities, such as the Three-Gorge project. Based on the sea maps from 1850' to 1980', the DEM (Digital Elevation Model) of the estuary is produced by the tool of GIS. The temporal and spatial variations of estuarine geomorphology are analyzed. The results demonstrate that the erosion-deposition of the Yangtze estuary has been different from the past and the pattern of erosion-deposition is summarized as a stable, two eroded and four depositional parts. The discharge decrease is the most important factor which resulted in the coastal erosion and at the same time, some preliminary countermeasures on the issue are discussed.