Spatiotemporal evolution and driving factors of China’s flash flood disasters since 1949

This study examines the spatiotemporal evolution of China’s flash flood disasters (FFDs) since 1949 and explores driving factors affecting the spatial distribution of historical FFDs. Records of more than 60000 FFDs are examined, and the centroid comparison method is used to reveal the spatiotemporal evolution of FFDs from 1951 to 2015. In particular, the geographical locations of the centroids, degrees of aggregation, and associated movement tendencies are examined to conduct a preliminary analysis of correlations between rainfall, population, and the spatiotemporal evolution of FFDs. Subsequently, using relevant data from 2000 to 2015, three factors relating to FFDs in natural watershed units include namely rainfall, human activity, and the environment of the Earth’s surface. The geographical detector method is then employed to explore the effect of these driving factors on the spatial distribution of FFDs. Analysis results show that displacement of the spatial distribution of FFDs since 1949 is correlated with variations in rainfall and population distribution. In addition, it is determined that the distribution of FFDs occurring between 2000 and 2015 have regional differentiation characteristics. However, the effect of rainfall on the distribution of FFDs is more significant than that of human activity or the environment of the Earth’s surface, but interactions occur between these latter two factors in disaster-formative environments. Furthermore, results also show that the driving factors of FFDs have significant spatiotemporal heterogeneity. In China, regions at high risk of FFDs include the Sichuan-Chongqing ecological zone, the South China ecological zone, the Yunnan-Guizhou Plateau, and the middle and lower reaches of the Yangtze River, while regions with a low risk of FFDs include the Northwest China arid zone, Qinghai-Tibet Plateau, Inner Mongolian Plateau, and the Northeast China ecological zone. These findings support further studies investigating disaster-formative environments, facilitate FFD risk zoning, and provide a scientific basis for plans to effectively prevent and control FFDs.