Abstract: There are some methods used in calculation of design flood for ungauged basin, namely rational formula method, integrated unit hydrograph method and regional synthesis method. The rational formula method is commonly applied in ungauged basin whose area is less than 50 km², according to the design storm. However, the integrated unit hydrograph method is suitable for the basin larger than 50 km². The regional synthesis method is used for calculating design flood on the basis of catchment area as well as the relation between statistical flood parameters and catchmat area. In this study, the application of rational formula method and regional synthesis method has been discussed for specific basin.

Key words: rational formula method, regional synthesis method, design flood, case study

摘要： 无资料地区设计洪水分析主要常用的方法有推理公式法、瞬时单位线法、地区综合法等。其中推理公式法采用设计暴雨推求设计洪水，部分地区适用于流域面积小于50 km2；瞬时单位线也采用设计暴雨推求设计洪水，部分地区适用于流域面积大于50 km2；地区综合法是通过建立水文站洪水统计参数与汇水面积关系线，根据工程流域面积推算设计洪水成果。以设计洪水实例为论证，主要分析推理公式法和地区综合法两种方法成果的差别及取用。

关键词: 推理公式法, 地区综合法, 设计洪水, 实例