三峡水库提前蓄水的防洪风险与效益分析

在三峡水库现有优化调度和试验性蓄水方案的基础上，拟定了6组提前蓄水方案，开展提前蓄水的防洪风险和效益分析计算。选择1952和1964年为典型年，分别推求分期设计洪水过程线。研究结果表明：三峡水库9月1日从145 m开始起蓄，9月30日均匀蓄至160.0m，其1 000年一遇分期设计洪水对应的风险率和风险损失率分别为0.39%和1.47%，防洪风险仍在可控范围内；与原方案相比，多年平均可增加发电量24.65亿kWh，减少弃水量25.32亿m ³，汛后蓄满率和平均蓄水位分别提高到95.35%和174.8m。

Flood Control Risk and Benefit of Impounding Water in Advance for the Three Gorges Reservoir

On the basis of optimal operation and experimental water impoundment scheme for the Three Gorges Reservoir, 6 different schemes of impounding water in advance were proposed. The flood control risk and comprehensive utilization benefits were calculated to determine the optimal impoundment schemes for the Three Gorges Reservoir. Two typical years of 1952 and 1964 were selected to obtain the seasonal design flood hydrographs. Results show that the best scheme is to impound water from 145m on September 1 to 160.0m on September 30 with a continuous and uniform process. The flood control risk ratio and risk loss ratio of seasonal design flood once in 1 000 years are 0.39% and 1.47% respectively, which are within controllable range; compared with the original scheme, the optimal schemes can generate 2.465 billion kWh extra hydropower and save 2.532 billion m3    flood water resource. The full storage ratio and average storage level at the end of impounding period increase to 95.35% and 174.8m, respectively.