流域特性对中国干湿区发生不同类型洪水的影响分析

An Analysis of the Impacts of Catchment Attributes on the Occurrence of Different Flood Types in Cold, Dry and Wet Regions of China

洪灾是威胁人类生命财产安全的主要自然灾害之一,开展流域特性对洪水发生的影响研究有助于深入把握洪水发生的物理机制,为科学有效的抵御洪灾提供重要理论依据。当前国内外学者研究流域特性对洪水发生的影响主要采用物理模型模拟法和统计学方法,其中STEIN等[1]提出的统计学方法具有对数据的精度要求较低、操作简单等优点,并且可以对干湿区进行分类分析,但该方法当前尚未在中国境内应用研究,因此有必要利用该统计学方法开展流域特性对中国干湿区发生不同类型洪水的影响分析。采用STEIN等[1]提出的洪水分类决策树对中国境内201个流域发生的洪水进行分类,利用经验累积概率对比法分析流域特性对干湿区洪水发生的影响。研究主要结论如下:寒区发生频率较高的ROS、ER型洪水,其中ROS洪水受流域面积、平均高程的削弱作用较大;ER洪水受降雪和降雨加剧作用较大、受土壤含水量削弱作用较大;干旱区发生频率最高的LR型洪水受降雨和降雪加剧作用较大;对于湿润区发生频率较高的SM、LR型洪水,SM洪水受降雨和黏土含量加剧作用较大、受沙土含量和平均坡度削弱作用较大,LR洪水受降雨和黏土含量加剧影响较大、受坡度和沙土含量削弱影响较大。基于研究结果,水利管理部门可以合理规划工程和非工程措施干预洪水发生的主导流域特性,有针对性的抵御流域内不同类型的洪水。

Floods are one of the major natural hazards threatening human life and property safety.The study of the impacts of catchment attri⁃butes on the occurrence of different flood types helps to grasp the physical mechanism of flood occurrence and provides an important theoreti⁃cal basis for scientific and effective flood prevention.Most scholars mainly use physical model simulation and statistical methods to study the impacts of catchment attributes on flood occurrence. The statistical method proposed by Stein et al.(2021) has the advantages of requiringless precision in data, simplicity in operation, and the ability to analyze separately for cold, dry and wet regions. The method of Stein et al.(2021) has not been applied in China, so it is necessary to use this method to analyze the impacts of catchment attributes on different floodtypes in cold, dry and wet regions of China. In this paper, flood classification decision trees are used to classify floods in 201 watersheds inChina, and the impacts of catchment characteristics on different flood types in cold, dry and wet regions are analyzed by the empirical cumu⁃lative probability comparison method. The main conclusions of this study are as follows: ROS and ER floods occur more frequently in cold re⁃gions, in which ROS floods are significantly weakened by basin area and mean elevation. ER floods are mainly exacerbated by snowfall andrainfall, and weakened by soil moisture content. LR floods, which occur most frequently in dry regions, are mainly exacerbated by rainfalland snowfall. For SM and LR floods, which occur more frequently in the wet regions, SM floods are mainly exacerbated by rainfall and claycontent and weakened by sand content and average slope, while LR floods are mainly exacerbated by rainfall and clay content and weakenedby slope and sand content. Based on the findings of this study, water management authorities can rationally plan engineering and non-engi⁃neering measures to intervene in the dominant watershed characteristics where flooding occurs, and target against different types of floodingin the watershed.