Research On Riverbank Stability And Riverbed Evolution Of The Water-source Regions Of The Water Diversion From Yangtze River To Tai Lake

In order to solve water environment problems in the watershed of Lake Tai, water diversion from Yangtze River to Lake Tai has been implemented since 2002 and gained a great deal of success. Apparently, some problems have also been pointed out. However, both riverbank stability and riverbed evolution of water-source regions directly influence the security of water diversion. Therefore, the research performs analysis on riverbank stability and riverbed evolution of water-source regions, considering the security of water-source region for water diversion from Yangtze River to Lake Tai, and provides the technical and scientific support for the studies of water-source region protection and security argument.The river regime of the Yangtze River section where the water-source region located varies intensely, and the hydrodynamic structure of that section is complicated. Meanwhile, because the region locates the developed areas, influence of human activities is of great severity. Especially, the south bank water-source located, which has a higher development and utilization ratio and severely filled up with the irrational exploration of bottomland, and bank lines near the west bank of Wangyu River all occupied by internationally industrial parks in Changshou, threatened the security of water-source region.Based on the analysis on the riverbed evolution of water-source, the primary riverbed of the Yangtze River change little, but the inner ditch in Fushan barbed drainage water-source region located is belonging to the period of erosion. The upper ditch maintaining the main hydraulic characteristics of the barbed now is situated the state of rapid erosion, so that sediment in Fushan barbed sharply increased and the riverbed increasingly silt up, resulting in the use of water-source region being limited. We could simulate the flow process of the Yangtze River on the basis of establishing two-dimension hydraulic model, applying on conservation of two-dimension unsteady flow shallow water equations to describe the flow of the Yangtze River, and applying on finite volume method and the Riemann solver to solve time-interval and unit-interval numerical solution of equations. Through the simulation for water-source and the assumed sediment of flow-field, the contrast indicates that the flow of the water-source region slow down and the silt-up rapidly increase. In addition, by calculating the channel characters in Fushan barbed, we can conclude that the actual width is greater than the steady width. The above results show that riverbed is unsteady and the barbed will continually silt up, which will have an unfavorable influence on water-source region.