Urban waterlogging risk assessment in well-developed region of Eastern China

Eastern China, a populous and economically developed area, is severely affected by various meteorological disasters under the background of global climate change. In recent years, urban waterlogs caused by heavy rainfall has become a major concern threatening urban safety and socioeconomic development. This paper aimed to reveal the spatial pattern of waterlogging risk in 89 prefecture-level cities of Eastern China by a comprehensive analysis on extreme rainfall, socioeconomic exposure and urban adaptability. Hazard intensity index was calculated on 20-year return period value of maximum daily precipitation. Exposure index was based on the total urban population and local gross domestic product, while adaptability index was an integrated evaluation of drainage pipeline density, river network density and greening rate of urban area. Risk assessment was a synthesis judgment of hazard intensity index, exposure index and urban adaptability index, according to which the cities in Eastern China were classified into five risk levels. The six cities with the highest level of waterlogging risk were Shenzhen, Beijing, Maoming, Yangjiang, Shanwei and Dongguan, which indicates relatively stronger intensity of meteorological hazard, higher density of socioeconomic exposure and the weakness of urban adaptability in these cities. The high risk cities would suffer much more losses than other cities in Eastern China when hit by an extreme rainfall. This paper could provide a scientific basis for urban waterlogging risk identification and governance, as well as for technical measures development and capacity building of disaster prevention and reduction.