Research On Multi-scale Quantitative Assessment Of Vulnerability To Flash Flood Disasters

Flash flood disasters have the characteristics of suddenness,susceptibility and seasonality.Their concentrated flow rate is large and their destructive power is strong,which seriously threatens the safety of people’s lives,property and infrastructure in mountainous areas.This paper comprehensively evaluates the vulnerability of flash flood disasters from different scales.The regional scale mainly starts from the two aspects of population and economy,and spatializes the key indicators of population and economy,the regional flash flood vulnerability assessment index system and evaluation model are constructed to realize regional comprehensive vulnerability assessment.For the small watershed scale,the method of numerical simulation is used to realize the vulnerability assessment and loss analysis of flash flood disasters in small watersheds.The research conclusions are as follows:1)Through spatial processing of population and economy,refined population and economic distribution data that can reflect regional differences are obtained,which provides key indicators for regional flash flood vulnerability assessment.2)Based on the principle of vulnerability assessment,combined with the principle of index selection,a regional vulnerability index system is established,and population and economic vulnerability assessments are carried out from the perspectives of population and economy.and build a comprehensive vulnerability assessment model to realize the vulnerability assessment of flash flood disasters in the Yalong River Basin.3)The highly vulnerable areas of population in the Yalong River Basin are discretely distributed in the basin;the highly vulnerable areas of economy are mainly distributed in the lower reaches of the basin;The comprehensive highly vulnerable area is also a highly vulnerable area in terms of population and economy.It is mainly distributed in the lower reaches of the basin,especially the most densely distributed on both sides of the Anning River and Jinsha River in the lower reaches,therefore,these areas should be the key prevention areas for flash flood disasters,and it is necessary to strengthen the protection measures for these areas.4)Based on the numerical simulation results,combined with population and economic data,the vulnerability assessment and loss estimation of flash flood disasters are carried out.It is found that the extremely vulnerable area is mainly located at the bend of the downstream of the watershed to the left and the lower part of the corresponding channel in the flooded area.The water depth in this area is relatively large and the damage caused is also relatively large.to a lesser degree;In addition,it can be seen from the loss estimation results that when a flash flood disaster of a similar scale occurs in the Xihe River Basin,the possible losses are relatively large.In summary,based on the geographical,population and economic distribution characteristics of the Xihe River Basin,combined with the inundation range of flash floods obtained by simulation,monitoring and early warning of flash flood disasters should be done to reduce or avoid possible losses.This paper evaluates the vulnerability of flash flood disasters from different scales,fully considers the damage caused by flash flood disasters at different scales,and provides a reference for formulating flash flood disaster prevention and control measures in a targeted manner,it is conducive to continuously improving the comprehensive defense level of flash flood disasters to meet the requirements of social and economic development,and has important guiding significance for disaster prevention and mitigation in mountainous areas.