三峡水库蓄水期洞庭湖出湖水量变化

基于长江与洞庭湖一、二维耦合水动力模型，模拟了三峡水库蓄水前后洞庭湖湖区的水文过程，定量分析了蓄水期三峡水库蓄水与洞庭湖出湖水量的响应关系。结果表明:蓄水期三峡水库蓄水减少了荆江三口进入洞庭湖的水量，同时也改变了洞庭湖湖容变化的速度；相比还原情况，各典型年下9-10月洞庭湖出湖水量均明显减少，且10月份减少幅度大于9月份，11月变化不显著；9-10月荆江三口水量变化是洞庭湖出湖水量变化的主导因素，而11月主导因素是湖容的变化。通过多元回归分析，构建了三峡水库蓄水量与洞庭湖出湖水量、湖容变化量的响应关系，在湖容不变情况下，洞庭湖出湖水量减少量约为三峡水库蓄水量的23%。

Research on change of the outflow of Dongting Lake during the refill period of the Three Gorges Reservoir

Based on the one- and two-dimensional coupled hydrodynamics model of the Yangtze River and Dongting Lake,the hydrological processes of the Dongting Lake area before and after the impoundment of the Three Gorges Reservoir were simulated. Quantitative analysis was carried out for the response relationship between the impoundment of the Three Gorges Reservoir and the outflowing water volume of Dongting Lake. The results indicate that the inflowing water volume of Dongting Lake from the three outlets along Jingjiang was reduced due to the impoundment of the Three Gorges Reservoir during the water storagerefill period. This also changed the variation speed of the Dongting lake storage capacity. Compared to the original conditions,the outflowing water volume of Dongting Lake was significantly reduced from September to October in each typical year,with greater reduction in October than in September,while the change in November was not distinct. The water volume change of the three outlets along Jingjiang from September to October was the dominant factor for the outflowing water volume variation of Dongting Lake,with the change of the lake storage capacity being the dominant factor in November. Through multiple regression analysis,the response relationship between the impoundment of the Three Gorges Reservoir,the outflowing water volume of the Dongting Lake,and the change of lake storage capacity was constructed. Under the conditions of constant lake storage capacity,the reduction of the outflowing water volume of Dongting Lake was about 23% of the impoundment of the Three Gorges Reservoir.