Abstract:
Based on the natural disaster risk assessment theory, this paper uses the hourly precipitation observation data of 1639 automatic stations from 2005 to 2019, the basic geographic information with a resolution of 30 m of Liaoning province in 2017, and the data of mountain torrents to study the risk zoning of mountain torrent disasters induced by heavy rain.The results of risk zoning are compared with the historical flash floods.The results show that through the statistics of the correlation between mountain torrent disasters and precipitation, the 6-hour rainstorm is more suitable as the disaster-causing factor of mountain torrents in Liaoning province.Therefore, a 6-hour comprehensive utilization classification of rainstorm intensity and rainstorm frequency is constructed to finely evaluate the disaster risk of a rainstorm.Data such as elevation of mountain torrent gully, ditch-bed gradient, and river network density can effectively evaluate the environmental sensitivity of mountain torrent disasters.The two risk exposure indicators of population density and cultivated land ratio, as well as the disaster sensitivity coefficient, can generally evaluate the vulnerability of disaster-bearing bodies.Compared with the spatial and frequency distribution of the historical mountain torrent disasters, the high-incidence areas of mountain torrent disasters are consistent with the high-risk areas in this risk zoning.Based on the accurate risk zoning results of each mountain torrent gully, the risk zoning accuracy of mountain torrent disasters has been improved.It provides a valuable reference for the precise defense of induced flash flood disasters.