中文摘要：

设计洪水地区组成是水利水电工程规划设计中的一个重要研究课题。本文将结构可靠度计算中的JC法引入，用于上游有水库调节的设计洪水地区组成的分析和计算，并结合典型洪水过程推求了设计断面的洪水过程线。该方法在求解洪水最不利地区组成的同时计算断面设计洪水的风险，不但能较好地考虑水库及区间对下游设计断面洪水的影响，而且弥补了现有方法不能计算设计洪水风险的不足，开辟了一条研究设计洪水地区组成的新途径。

英文摘要：

The design flood region composition is an important subject of hydroelectric project planning and design, In this paper, JC Method, which had been used to calculate structure reliability, is introduced and used to analyse the design flood region composition influenced by upper reservoirs, and then the design flood hydrograph is deduced from the typical flood hydrograph. Both the worst flood region composition and design risk can be obtained by this method. Not only this method can consider the impact of upper reservoirs, but also can calculate the design risk while other methods are unable to do so. A new approach is exploited to analyse the flood region composition.