THE ANALYSIS OF THE EASTERN CHONGMING TIDAL FLAT'S EVOLUTION IN THE YANGTZE RIVER ESTUARY

The eastern Chongming tidal flat is one of the main tidal flats of the Yangtze River estuary.Supported by Mapinfo7.0,3 pieces of the Yangtze Estuary from 1983 to 2003 are digitized and so that the area,the thickness of erosion-accretion and bathymetric contour progradation rate are calculated.Based on measured and collected data of topography from 1983 to 2003,sediment and hydrodynamics,the analysis of this area can give us some conclusions: 1During 1983 to 2001 the eastern Chongming tidal flat deposited and extended considerably,and the area of the tidal flat above 3.5m had increased from 33.6km2 to 98.8km2.2 An increase of the tidal flat above 0m in area was 4.2km2,but there was a decrease of 0.8km2 in area of the tidal flat above 2.0m and a decline in the average annual deposition rate of the tidal flat above 3.0m.3 Human's activities have an important effect on the development of the eastern Chongming tidal flat.