水库群复杂防洪系统的设计洪水及风险分析

The natural flow of a majority of the world's rivers has been substantially altered through dam construction, which brings great challenges to the work of design flood and flood risk analysis. Stochastic simulation method, considering the uncertainty in the flood flows and hydraulic connection between upstream and downstream reservoirs, can provide an effective way to describe the complex interactions of reservoirs in the comprehensive flood control system and predict the possible results of different design schemes. However, how to establish the multi-site daily runoff simulation model remain to be a great challenge to engineers and scientists, which still need to be investigated and studied. The copula entropy method will be introduced in this project to estimate the spatial dependence of multi-gauging stations. Based on the dependence analysis, the multi-site daily flow simulation model will be established. The flood coincidence risk will be analyzed according to the proposed model. After this, the design flood downstream of the dam will be calculated. At last, the flood risk downstream of the dam corresponding to the flood coincidence events will be analyzed, and the evolving rule of the coincidence risk in the reservoir systems will be explained. This research will crack the theoretical bottleneck of design flood and flood risk analysis in the comprehensive flood control system and improve the hydrologic frequency analysis method, which provide a significant impact on flood control and water resources managements.

水库群调蓄作用明显改变了复杂防洪系统中洪水时空分布规律及特性，给复杂防洪系统设计洪水计算及风险分析带来了挑战。随机模拟方法能充分考虑洪水时程分布的不确定性和水库上、下游的水力联系与补偿作用，是刻画复杂防洪系统各组成间相互关系、预测设计方案可能效果的一种行之有效的方法。然而，如何建立多站随机模拟模型仍是学术和工程界研究的重点和难点，有待进一步研究和探索。研究工作将引入Copula熵理论，研究多个站点的空间相关关系，提出刻画多站流量序列多维联合分布特性的数学描述方法，从而建立多站日径流随机模拟模型，在探究干支流洪水遭遇规律的基础上，提出理论依据充分、方案切实可行的复杂防洪系统中设计洪水计算新方法，揭示复杂防洪系统风险传递机制和演化规律，突破水库群复杂防洪系统设计洪水及风险分析的理论瓶颈，丰富和发展水文分析计算方法，为防洪决策和水资源的合理开发利用提供依据。

水库群调蓄作用明显改变了复杂防洪系统中洪水时空分布规律及特性，给复杂防洪系统设计洪水计算及风险分析带来了挑战。经过三年的努力研究 ，本项目取得了如下的成果：（1）引入了Copula熵理论，研究了多个站点的空间相关关系，提出刻画多站流量序列多维联合分布特性的数学描述方法。（2）建立了多站日径流随机模拟模型，为进一步的风险分析奠定了基础 。（3）根据复杂防洪系统中年最大洪水的偏态特性和难以用统一的分布函数描述的实际问题 ，提出了理论依据充分、方案切实可行的设计洪水计算新方法。（4）研究了水库建成后，在预报调度中，水文预报不确定性这一主要风险源的分布特性和演化规律，评估了水库群复杂防洪系统中的防洪风险。本研究突破了水库群复杂防洪系统设计洪水及风险分析的理论瓶颈，丰富和发展了水文分析计算方法，为防洪决策和水资源的合理开发利用提供了依据。