The Evolution Of The Riverbank Resources Of The Yangtze River In Jiangsu Province On GIS

Traversing Jiangsu province, the Yangtze River belong to lower reach and estuary of the river, it has more than 400km span, alluvial plain riverbed, large flux, small gradient, wide river surface, much sand and disorderly current. The variation of erosion and deposition of the riverbed is highly, because of the river current action. If the variation of erosion and deposition of the riverbed and the variation of alongshore water depth changed, the property of the riverbank resources changed. This had a strong impact on the port and the important engineering construction along the river.With the support of the state physical science fund item "the experiment of digital Yangtze river course - the case of the Yangtze River in Jiangsu province", the study about riverbank resources is carried out by the case of water depth. On the basis of it, the process, the law and the trend of the evolution of riverbank resources has analyzed and made a tendency forecast.The study has led to the fallowings and conclusions:1. The study has set up the water depth of sea-route database by selecting many phases of water depth of sea-route charts since 1954.Types of the riverbank resources has been abstracted automatically by computer on the database and adopting spatial analysis means of GIS.2. A comprehensive consideration of analyzing the riverbed and the wide of sea-route, section shape and hydrology condition, the standard of different channel segment of the riverbank resources to be classified was made. There are three segments: Nanjing - Jiangyin, Jiangyin - Xuliujing, Xuliujing - Liuhekou. Each segment took different value of alongshore of the riverbank, and was classified three types: deep water bank., mediate deep water bank and shallow water bank according to water depth.3. The riverbank resources was classified automatically at each phase and then the geo-information Tupu of riverbank resources of the Yangtze River in Jiangsu province is constructed.4. By analyzing the geo-information Tupu of riverbank resources in Jiangsu province, its features is :1) The evolution of the riverbed follows the law that the concave bank is erosible and the convex bank is alluvial. Usually the deep water is much in concave bend, whereas the shallow water is much in convex bend. And also there is much deep water in river constriction segment and in the area which has kickpoint controlled. The scale of deep water bank and shallow water bank are all much larger than that of the mediate deep water bank.2) In space, except the segment of left bend of the channel, where has kickpoint controlled, has the trend moves to the left, the whole riverbed has the the trend moves to the right, more zigzag and narrowing, but the whole river regime hasn't changed.3) Before 1976, the period is the prophase, after 1976, is anaphase .The riverbed is highly variable in prophase and less variable in anaphase.The study has some significance of theory on digital Yangtze river course, and also has some realistic value on exploiting and utilizing the riverbank resources and making port programming of the Yangtze River in Jiangsu province.