Flood Disaster Risk Research In Gansu Province

Flood disaster is one of the most common natural disasters in China.Gansu Province is located in the center of Chinese geography and geometry,at the intersection of the Loess Plateau,Qinghai-Tibet Plateau and Inner Mongolia Plateau.It has complex and diverse landforms,numerous rivers,heavy local rainstorms and frequent flood disasters,which threaten people’s life and property safety and restrict local economic and social development.Comprehensive flood risk research is urgently needed.Flood disaster is one of the most common natural disasters in China.Gansu Province is located in the center of Chinese geography and geometry,at the intersection of the Loess Plateau,Qinghai-Tibet Plateau and Inner Mongolia Plateau.It has complex and diverse landforms,numerous rivers,heavy local rainstorms and frequent flood disasters,which threaten people’s life and property safety and restrict local economic and social development.Comprehensive flood risk research is urgently needed.Based on fuzzy mathematics theory and GIS technology,this paper draws the flood risk distribution map of 2000,2005,2010,2015 and 2020 in Gansu Province,explores the spatialtemporal variation characteristics of flood disaster risk in Gansu Province,and establishes the projection pursuit model to classify the historical flood levels.Based on this,the major flood year of Gansu Province is forecasted.This study enriched the research results of large-scale flood disaster risk in Gansu Province,provided theoretical basis for flood disaster management in Gansu Province,and had important significance for flood control and disaster reduction and regional social and economic stability.The main research conclusions are as follows:(1)The flood disaster risk distribution from 2000 to 2020 has obvious spatiotemporal variation characteristics.In terms of time,the low risk area,slightly high risk area and high risk area decreased,while the general risk area increased.In terms of spatial distribution,it is higher in southeast and lower in northwest,and the city is higher than the countryside.(2)From 1990 to 2020,different levels of floods occurred alternately,with a total of 6 years of major disasters,5 years of major disasters,13 years of general disasters,and 7 years of minor disasters.Meanwhile,the trend of changes in flood disasters is basically consistent with the overall risk changes.(3)The mean square error of the grey Markov model optimized by PSO is smaller than that of the grey Markov model,and the model is more accurate.Based on the PSO grey Markov model,the occurrence time of the 10 th and 11 th flood years since 1990 is accurately predicted,and the 12 th flood year is predicted to be 2023.