考虑洪水地区组成不确定性的水库下游防洪风险率计算

Flood-control Risk Ratio Calculation of Reservoir Downstream Considering Flood Space Allocation Uncertainty

随着水库群的调节对下游洪水过程的影响越来越突出,科学评价下游控制点的防洪风险率对复核流域防洪标准、优化水库群防洪调度规则具有重要意义。传统计算方法对洪水地区组成不确定性考虑不足,影响了评价成果的可靠性。针对单库防洪系统,提出了计算水库下游防洪风险率的离散求和-均值一次二阶矩法,该方法不仅能考虑洪水地区组成的不确定性,还能描述该不确定性在防洪系统中的传递特征。将该方法应用于分析沭河流域沙沟-青峰岭防洪系统,结果表明,沙沟水库下游青峰岭断面的防洪风险率为4.02%,满足该防洪系统20年一遇的防洪标准。

As the multi-reservoir regulation impacts apparently the downstream flood hydrographs,to evaluate scientifically the flood-control risk of the downstream control points is important for basin flood-control standard verification,as well as multi-reservoir flood control rules optimization.The traditional methods consider the uncertainty of flood space allocation insufficiently,which may influent the reliability of the evaluation results.This article presents discretization summation-mean first order second moment method for flood-control risk ratio calculation at downstream control points of a single reservoir.The presented method considers the uncertainty of flood space allocation,describes the transfer characteristics of that uncertainty in the flood control system as well.The method was applied to Shagou-Qingfengling flood-control system,and the results indicate that the flood-control risk ratio of downstream control point Qingfengling of Shagou Reservoir is 4.02%,which satisfies the 20-years flood-control standard.