INFLUENCES OF THE SHRINK OF DIVIDING CHANNELS AND THE DONGTING LAKE ON THE FLOOD IN THE YANGZTE RIVER

The flood disaster along the Yangzte river in 1998 which broughtabout enormous economic losses to Chinese people shows that the floodcontrol system of the Yangzte River is still very weak despite ofenhanced capabilities of flood prevention in these years. Focusing onthe Jingjiang River and Dongting Lake area, a numerical FVMmodel is established to study flood routing in this complicated water systemconsisting of one-dimensional rivers and two-dimensional lakes. By applyingthis model, the simulation of flood motion in the river network owing to geographical environment factors are analyzed in detail.Two important factors that may cause high stages in the Jingjiang Riverduring the 1998 Yangzte River flood period have been identified. They are,the blockage of the dividing rivers and shrink of the Dongting Lake.According to this research, a number of measures can be adopted to mitigate theflood disaster in the Yangtze River valley.