中文摘要：

梯级建设环境下水电工程施工导流系统风险受到上游梯级洪水蓄泄和下游梯级水库运行的影响。基于对上游已建梯级、区间洪水、支流汇入、上游在建梯级和下游在建梯级等主要组成部分的影响分析，计入上游水库调蓄、区间河槽调蓄作用，考虑天然洪水、上游梯级泄流能力、支流汇入洪水及其叠加方式、区间洪水、下游梯级回水和施工导流系统泄流能力等不确定性因素，按影响次序叠加得到施工洪水，以洪水下泄过程模拟为主要的因素耦合方式，建立梯级建设环境下水电工程施工导流风险测度模型，应用Monte-Carlo方法求解风险度。研究成果为金沙江下游白鹤滩电站施工导流标准决策提供了参考。

英文摘要：

Risks in a construction and diversion system of hydropower project with cascaded reservoirs depend on the flood control of upstream reservoirs and downstream reservoir operation and environmental control. This paper develops a diversion risk evaluation model that simulates flood discharge process to couple the major factors, such as upstream water release, interval-basin flood, branch afflux, and construction of upstream and downstream stations, upstream reservoir regulation, river channel storage, and uncertainties in natural flood, upstream station discharge capacity, branch afflux and its superposition method, interval-basin flood, downstream reservoir backwater level, and construction diversion system. This model uses Monte-Carlo Method to evaluate diversion risk. The present study provides references for the decisions on the diversion standard of Baihetan project on the lower Jinsha River.