FLOOD-CONTROL AND DISASTER-REDUCTION CONTRIBUTION OF THE FLOOD-CONTROL DISPATCH OF THE THREE GORGES RESERVOIR IN THE DONGTING LAKE AREA

The Dongting Lake area is one of the areas in China where the floods frequently happen.The floods in 2010 is the first worse flood after the floods of the Yangtze River in 1998 and the water storage of the Three Gorges Reservoir.There are 5 flood-control dispatches of the Three Gorges Reservoir during the process of the 5 floods,which reduces the pressure of fighting against floods to a large extent in the middle-lower area of the Yangtze River.The Jingjiang River is not only the ties connecting the Three Gorges Reservoir and the middle-lower Yangtze River but also the current pass linking the Dongting Lake area.So,all the following questions deserve to be considered:How many effects on the water regimes in the Dongting Lake area were caused by the flood-control dispatch of the Three Gorges Reservoir?How big is the contribution rate of reducing the loss caused by the floods in the lake area?Based on the field-survey hydrology data,the disaster data and the hydrology corresponding relationship among the outflow volume from the Three Gorges Reservoir,the Three Outlets and Chenglingji,the flood-control and disaster-reduction contribution rate in the Dongting Lake area of the flood-control dispatch of the Three Gorges Reservoir in the flood seasons in 2010 is comparatively analyzed.The results are shown as follows.1.The flood volume from the Three Outlets decreases by 242.61×108 m3 and the flood level of Chenglingji fell by 0.82 m from Jun.to Aug..2.The reduction in the direct economy loss in the lake area caused by the flood was about 19.983×108 $ and the reduction in the indirect economy loss was about 0.638×108 $.