百年一遇洪水内涵及易于引起误解的若干问题分析

100-year flood and misinterpretations of its return period

近20年来,受气候变化和人类活动双重影响,极端洪水事件发生频率增加。每当出现洪水灾害时,公众都会对洪水重现期的专业表述产生误解。为帮助公众正确理解洪水重现期的确切含义,避免产生概念混淆和内涵误解,本文首先从洪水重现期定义出发,阐明其概念和内涵;然后以百年一遇重现期为例,通过实例分析百年一遇洪水在100年内可能发生的次数、洪水重现期与已有观测洪水数据的多少、气候变化和人类活动的关系以及洪水重现期与暴雨重现期的区别等;最后给出结论以及对N年一遇洪水专业表述进行修改的建议。

Over the past two decades,with the impact of climate change and human activities,extreme flood events have occurred frequently in China,which has become one of the major concerns in the coun⁃try.Each time floods take place,the terminology of the return period or recurrence interval of a flood is misinterpreted by the public.In order to help the public learn about the exact meaning of the return peri⁃od and avoid misunderstanding its concept and connotation,this paper,at first,starts with the definition of the return period,clarifying its concept and connotation.Then,with a return period of 100 years as an example,case studies are selected to analyze and answer such questions as how many times a 100-year flood is likely to occur within 100 years,how it is dependent on flood data observed in the past,how it is affected by climate change and human activities,and what is the relationship between the return periods of a storm and its corresponding flood.At last,the paper draws some conclusions and gives the suggestion that the terminology of an N-year flood be revised.