Flash flood risk assessment and driving factors: a case study of the Yantanxi River basin, southeastern China

This study took tropical cyclones–extreme precipitation–flash floods as an example to carry out a risk assessment of flash floods under climate change in the Yantanxi River Basin, southeastern China. To obtain the flash flood inundation characteristics through hydrologic–hydrodynamic modeling, the study combined representative concentration pathway (RCP) and shared socioeconomic pathway (SSP) scenarios to examine the change of flash flood risk and used the geographical detector to explore the driving factors behind the change.

The results show that flash flood risk in the Yantanxi River Basin will significantly increase, and that socioeconomic factors and precipitation are the main driving forces. The assessment results highlight that the changes in climatic and socioeconomic conditions increase the risk of flash floods. For people living in areas affected by flash floods, there is a need to increase education and awareness of flash flood precautions. Our findings suggest that socioeconomic development will boost regional disaster prevention capacity, but at the same time drive the increase in flash flood risk. Considering these impacts, balancing economic growth, risk management, and risk avoidance is an important issue that needs to be addressed in the long-term development of the area, which is strongly supported by tourism.