浅析历史特大洪水在设计洪水中的作用

Analysis of Effects of Historical Extraordinary Flood Events on Design Flood

运用统计分析方法，研究了实测系列中加入４种不同情况的历史洪水对设计洪水的影响。结果表明：加入的历史洪水重现期越长，则设计洪水成果的稳定性越好；在同一历史洪水考证期内，加入１～２个历史洪水对提高设计洪水成果的稳定性和精度作用很明显，加入更多的历史洪水则对进一步提高设计洪水成果稳定性和精度的作用不大；尽管历史洪水重现期有一定误差，但仍能有效地提高设计洪水成果的稳定性；历史洪水值的误差对设计洪水的影响比它的重现期误差对设计洪水的影响大得多。

The effects of historical extraordinary flood events added to observed flood series on design flood, in four different cases mentioned in this paper, have been studied with statistical method. The results show as the following: (1)The longer return period of the events, the more stable and accurate is the design flood. (2)In the same return period, the effects of improving the precision or stability of design flood are quite visible when the observed flood series is added one or two extraordinary flood events, but invisible on the contrary when more the events are added. (3) Errors of the return period can not influence the events' improving the precision and stability of design flood. (4) Effects of value errors of the events on precision of design flood are more visible than their return period errors.