摘要
为充分发挥三峡水库的综合效益 ,本文在三峡水库汛末洪水特性分析基础上 ,对水库 9月份各旬设计洪水进行频率和调洪计算 ,并给出了 9月份不同时间蓄水下水库各旬洪灾的风险率和风险损失 ,据此分析了汛末不同时间蓄水对水库防洪的影响。结果表明 ,三峡水库 9月份各旬的设计洪水均小于汛期设计洪水 ,且呈逐旬递减的趋势 ,只要水库汛末提前蓄水的时间恰当 ,不会给水库防洪带来风险。例如 ,对于 9月份 1 %设计洪水 ,水库 9月 1 6日以后蓄水的洪灾风险率和风险损失均为 0。
In order for the Three Gorges Project (TGP) to bring about more benefits to the middle reach of the Yangtze River, the present paper aims to provide a detailed analysis of the influence of the pre-scheduled impounding in the flood recession period on the flood control of TGP. Due to the complex and arbitrary nature of the impounding load, the Three Gorges Reservoir's water can usually not reach an impounding level over 175 m by the end of October in an average year according to the originally designed scheme, which would be likely to result in a great loss of its hydro-power generating capacity. Considering that the watershed altitude between the dam site of TGP and the Yichang hydrographic station differs rather slightly, the hydrologic data of Yichang has been used to analyze the flood characteristics during the flood recession period of TGP in this paper. First of all, the incoming flow from September to October and the probabilities of major flood occurring in September is analyzed based on the measured and investigated data of Yichang. Secondly, the designed flood frequency during the ten days of every September period has been calculated and the related water levels in front of the dam are obtained through flood recording routine. Next, taking the lower reach flood as a kind of unexpected occurrence, the flood damage and danger in the due period are also taken into account respectively. The paper has also analyzed the influence of a pre-scheduled impounding on the flood control in terms of human resources and material losses and damage in case the highest water level exceeds the limit in front of dam during the computed year concerned. Thus conclusion can be in the final analysis obtained as follows: (1) The flood with a peak rate above 50 000 m 3/s has hardly ever occurred after Sept. 20, however, the designed highest flood level in every period of ten days of September is less than those in July and August; (2) It wouldn't bring the flood control any risk if the impounding time is unexpectedly coming in advance. For the 1% design flood in September, both the flood damage and risk rate will be equal to zero if the reservoir impounds occur after Sept. 16. Hence, the results of the present analysis can be used for the actual TGP operation.
出处
《安全与环境学报》
CAS
CSCD
2003年第4期22-26,共5页
Journal of Safety and Environment
关键词
防洪工程
三峡
设计洪水
汛末蓄水时间
防洪风险
flood control engineering
Three Gorges Project
design flood
impounding time in the flood recession period
flood risk
