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依据1842～1997年10幅不同年代的长江口海图资料,利用地理信息系统和数字化仪进行处理,建立不同时期的长江口水下数字高程模型,以此作为基础资料,实现了从横剖面、深泓线纵剖面、平面变化等不同角度对长江口拦门沙地区滩槽演变、岸线侵蚀、沙岛形成与变迁等进行研究.通过计算河槽容积,实现了对不同时段泥沙冲淤量的计算.结果表明,155a来拦门沙总的趋势是不断淤积,但不同时期淤积速度大不一样,个别时期甚至会发生一定程度的冲刷,这主要与动力条件的波动有关.1842～1997年,共淤积泥沙38.10亿t,平均每年淤积 0.246亿t,约占长江来沙的5％,年均淤厚为1.1cm 泥沙淤积部位主要在九段沙、横沙及横沙东滩、崇明东滩三处.发生冲刷的范围较小,仅占总面积的21.4％,主要在北槽,北港上段和南槽局部也有轻微的冲刷发生.
Based on the Changjiang Estuary chart data from 10 different years from 1842 to 1997, the paper uses the geographic information system and digitizer to process and establish the digital elevation model of the Changjiang Estuary at different periods. Based on this, the data from the cross section, depth The longitudinal section of the line, the plane change and other different perspectives on the Changjiang estuary barren sand area beach evolution, shoreline erosion, sand island formation and change etc .. By calculating the channel volume, to achieve the amount of sediment deposition in different periods The results show that the general trend of 155M barrage is to keep silting, but the siltation rates in different periods are quite different, and even a certain degree of erosion will occur in a certain period, which is mainly related to the fluctuation of dynamic conditions.From 1842 to 1997, A total of 3.801 billion tons of sediment was deposited, with an average of 246 million tons of sedimentation each year, accounting for about 5% of the total sediment in the Yangtze River. The annual sediment deposition was 1.1 cm. Sediment deposition sites were mainly in Jiuduansha, Hengsha and Hengsha Dongtan, Chongming East The area of erosion is relatively small, accounting for only 21.4% of the total area, with minor erosion occurring mainly in the northern channel, the upper part of the northern port and the southern channel.