EVOLUTION PATTERN OF COASTAL EROSION IN THE YANGTZE RIVER ESTUARY

This study is focused on the evolution of coastal erosion during the past two decades in the Yangtze River estuary, a complicated river mouth area. Based on the analyses of geological data obtained in the coast during 1980s using the GIS(Geography Information System) and DEM(Digital Elevation Model) methods, we made a preliminary study on the newest distribution pattern of coastal erosion and growth in the estuary. The results demonstrate that the north branch of the estuary is disappearing under erosion while the south branch is growing. In a selected typical erosional area,we studied the beach profiles in different times. In accordance with the shapes of profiles, they can be divided into different types such as smooth and straight coast, wide and steep coast, and sharp and steep coast. In accordance with the variation of profile features, they can be divided into types of parallel and retreating,from concave to convex upward, and from wide and steep to sharp and steep.