长江河口岸滩侵蚀演变模式

EVOLUTION PATTERN OF COASTAL EROSION IN THE YANGTZE RIVER ESTUARY

  • 摘要: 长江河口地区由于流域带来的泥沙沉降堆积,形成了巨大的长江三角洲平原和水下三角洲。近年来,由于水土保持和流域建水库使得入海泥沙迅速减少,造成长江河口区岸滩侵蚀态势逐渐加重。根据多年海图资料得到的岸滩剖面变化,长江河口区岸滩侵蚀的演变模式按岸滩侵蚀剖面形态特征分为平直型、宽陡型和尖陡型;按剖面的变化特征可分为平行后退型、下凹变上凸型和宽陡变尖陡型。

     

    Abstract: 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.

     

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