GIS支持下的长江江苏河段深槽冲淤演变探讨

GIS-supporting study on siltation and erosion changes of Jiangsu reach of the Yangtze River

GIS强大的空间分析和空间数据库功能,提供了其它研究手段难以解决的河道水下地形冲淤变化分析及空间分布等问题的有力工具。本文在GIS技术的支持下,利用6个测次的长江(南京以下段)航道图数据,建立研究区域河道水下地形数据库,分析了河道冲淤变化及空间分布,分析计算结果表明研究区域1995年以前净面积减少,以冲刷为主,局部地区有淤积,但冲刷量大于淤积量,在1983年至1987年间净减少面积最大值为17.94km2.a-1;1995年以后净面积增加,以淤积为主,年净增面积达到13.43km2.a-1。同时基于GIS技术对河道形态、冲淤部位等进行实时的可视化显示,进一步对河道冲淤变化进行高效、准确的定量分析,更能有利于发现河道冲淤规律,为洪灾成因和防洪减灾对策研究提供决策支持。

Geographical information system （GIS） are drawing more and more attention in the field of underwater topography analysis because of the powerful spatial analysis and spatial database management. The aim of this study is to evaluate the dynamic changes of siltation and erosion from 1977 to 2001 of the Yangtze River supported by GIS. The multi-period spatial database of underwater topography was designed and constructed and underwater topography 3D-visualization and analysis application was given. The results show that （1） From 1992 to 1995, the siltation area and amount are quite big. The annual averaged siltation area and amount are 84.82km^2 and 0.30 × 10^9m^3 respectively. （2） From 1992 to 1995, the erosion is dominant and the annual averaged erosion area is 79.72km^2. （3） From 1995 to 2001, the erosion quantity is prety big and the annual averaged erosion quantity is 0.17 ×10^9m^3 . The current trend of the study area is that siltation tends to decrease and erosion tends to increase.