Urban flood inundation and damage assessment based on numerical simulations of design rainstorms with different characteristics

In the context of global climate change and urbanization, urban flooding is an important type of natural disaster that affects urban development, especially in China, which is experiencing rapid urbanization. In the past 10 years, urban flooding events have caused huge disaster losses in Chinese cities. This has resulted in significant negative effects on the urban infrastructure, socioeconomic systems, and urban residents, thus causing widespread concern. Studies have confirmed the change in extreme rainstorms is due to the changing environments in many cities globally Conducting studies on the impact of these rainstorms with different characteristics for urban flooding is valuable for coping with unfavorable situations In addition, numerical simulations provide an economical and viable means to perform these studies. This paper presents a numerical model of Xiamen Island in China. Simulations were conducted for 12 design rainstorm events with different return periods, rain patterns, and durations. The results indicate that, in the case of an equal rainfall amount, the rainfall intensity is the key factor that affects the inundated area, depth, and damages. However, the rainfall intensity is not the only determining factor; the rainfall pattern also affects the inundations. In regard to the rainfall pattern, a higher rainfall peak coefficient usually leads to severe urban inundation and damage. As a result, the lag time would be shorter, which may further exacerbate the impact of urban flood disasters. The results of this study provide insights into managing flood risks, developing urban flood prevention strategies, and designing flood prevention measures.