Identifying and analysing the differences between flooding and waterlogging in urban areas

There is a significant difference between the measures taken by urban flooding control department for flooding and waterlogging in urban areas. However, there is no clear definition method for flooding and waterlogging, and it is difficult to characterise flood and waterlogging in cities by quantitative means. The aim of this paper is to analyse the difference between flood and waterlogging and their potential relationship, and to propose a flood and waterlogging identification method based on the fuzzy comprehensive evaluation method. By extracting the dynamic attributes of flooding and waterlogging, the quantitative identification of both is achieved using fuzzy comprehensive evaluation, and empirical analyses are carried out using the Zhongyuan and Erqi districts of Zhengzhou City as case studies. Differential analyses show that flooding is mainly caused by the entry of foreign water bodies, while waterlogging is caused by excessive local precipitation leading to waterlogging, and the two are transformed into each other and superimposed under extreme conditions, resulting in a complex disaster for the city. The results of the identification for flooding and waterlogging in the study area indicated that the overall hazard of waterlogging is greater within the city limits, but the impact of localised flooding cannot be ignored. Especially in densely populated areas with low topography, flooding and waterlogging and their superimposed effects combine to increase the risk of flooding and the difficulty of disaster response.