三峡水库防洪调度运行对洞庭湖区防洪减灾的贡献

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

位于长江中游的洞庭湖区为中国洪涝灾害频发地区之一。2010年的洪水是长江1998年大水后,也是三峡水库蓄水运用以来所遇到的首次较大洪水,在5次洪水过程中,三峡水库实施了5次防洪调度,较大程度地减轻了长江中下游地区的洪水压力。长江中游荆江既是连接三峡水库和长江中下游河道的纽带,又是沟通洞庭湖的水流通道。基于三峡水库出库流量与荆江三口、洞庭湖城陵矶的水文对应关系,以实测水情、灾情资料为依据,运用对比分析方法,揭示2010年汛期三峡水库防洪调度对减轻洞庭湖区的洪水压力及减少洪涝灾害损失的贡献率。结果表明:6～8月份三口入湖洪量减少约242.61×108 m3,湖口城陵矶洪水位降低0.82m;湖区减少洪涝灾害直接经济损失约19.983×108元,间接经济损失约0.638×108元。

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 0.638×10^8 $.