Why Flash Floods Occur Differently across Regions? A Spatial Analysis of China

Abstract

In recent years, flash floods have increased, accompanying rapid economic growth, changes to the natural environment and increases in extreme climate events. However, spatial heterogeneity in the influencing factors has seldom been studied systematically. This paper investigates this issue by using the Geodetector tool and considering 14 factors such as climate, natural environment, and human activities in 11 ecoregions in China based on flash flood records from 1950 to 2015 collected by the Investigation Project of Chinese Flash Floods. The results showed that there is obvious spatial heterogeneity in the main influencing factors and influencing weights in 11 ecoregions. Precipitation and landforms have the greatest effects on flash floods and the interactions of these two factors have the strongest effects as compared to interactions between other factors in most of the 11 ecoregions; however, the effect has obvious variation from northwest to Southeast. Meanwhile, human activities were found to have tangible impacts, especially in ecologically vulnerable regions. The findings provide a new understanding of how and why flash floods occur in a particular region and contribute to the formulation of regionally targeted strategies to cope with flash flood.