Flood And Waterlogging Disaster Risk Assessment In Henan Province Based On AHP-entropy Weight Method

The first national comprehensive natural disaster risk survey has laid the foundation for the implementation of regional risk assessments and is of great significance to the promotion of disaster risk awareness in society as a whole.In recent years,natural disasters have occurred in many parts of China,causing serious damage to people and property,with floods being at the forefront of natural disasters with a high degree of damage and a wide range of impacts.Henan Province is located in central China,with a flat topography and a plain area in the centraleastern part of the country,which is subject to a monsoonal climate with high rainfall and a high risk of flooding.This paper takes Henan Province as the study area,and based on GIS and the AHP-entropy weight method,14 assessment factors affecting four aspects of flood hazard causation factors,sensitivity of the breeding environment,vulnerability to loss of disaster-bearing bodies and disaster prevention and mitigation capacity are selected from precipitation data,socio-economic data and topographical data,and a comprehensive risk assessment model is constructed to assess them and analyse their spatial correlation,using The assessment results are validated by the flood removal area from 2000-2019 and the results of other scholars’ studies.Based on the ARIMA model to predict the percentage of precipitation distance from 2022 to 2024,the prediction results and assessment results are combined to provide suggestions for risk response and management.The conclusions of this paper are as follows.(1)By referring to a large amount of literature and combining the current situation of flooding in Henan Province,strong flood frequency,general flood frequency and average annual precipitation are selected as the assessment factors for the risk of disaster-causing factors,river network density,vegetation cover,elevation and slope are selected as the assessment factors for the sensitivity of disaster-prone environment,economic density,per capita sown area,livestock share in the economy and population density are selected as the assessment factors for the vulnerability of disaster-bearing bodies to loss The factors of disaster prevention and mitigation capacity were selected as the assessment factors of disposable income per capita,density of medical and nursing personnel,and per capita food production,and the reasons for the selection of each factor and its characteristics were explained.(2)Based on the AHP-entropy weighting method,the four impact indicators of flood risk in Henan Province were assessed as follows:for the risk of disaster-causing factors,the highrisk areas were mainly located in Dengfeng City,Gongyi City,Shaanxi District and Hubin District,accounting for 2.79%of the total area,while the medium-high risk areas were mainly located in Luoyang City and Sanmenxia City in the northwestern part of Henan Province,with an area of 42,966km2;for the The high sensitivity area is mainly located in the northern part of Henan Province,accounting for 6.33%of the total area,while the medium to high sensitivity area covers 54,931km2,accounting for 33.43%of the total area.For the vulnerability to loss of disaster-bearing bodies,the eastern part of Henan Province,along the Beijing-Guangzhou Railway line,has a high vulnerability to loss.Areas of high susceptibility to loss are mainly located in Zhoukou,Zhumadian and Xuchang,with an area of 49,362km2,while areas of medium to high susceptibility to loss are located in Shangqiu and most of Xinxiang,accounting for 29.78%of the total area;for disaster prevention and mitigation capacity,there is a trend of gradual increase from south to north.Areas with low disaster prevention and mitigation capacity are mainly located in the western region,accounting for 16.24%of the total area,while areas with medium to low disaster prevention and mitigation capacity are mainly located in the south and east,covering an area of 73,625km2.(3)A comprehensive risk assessment of flooding was carried out by combining the four impact indicators,and the following conclusions were obtained:the high-risk areas in Henan Province are mainly concentrated in the Yellow-Huai Plain in the east and the Yiluo River Plain in the northwest,with an area of 17,420km2;the medium and high-risk areas are concentrated in Shangqiu City,Zhumadian City and the counties on both sides of the upper reaches of the Ying River,accounting for 17.55%of the total area;the medium-risk areas are concentrated in Xinyang City in the northeast and south,with an area of 42,231km2.The low risk area and medium-low risk area are mainly distributed in the Fuyiu Mountains in the west and the Dabie Mountains in the south,accounting for 13.60%and 17.55%of the total area respectively.(4)Analyzing the spatial autocorrelation of comprehensive flood risk through the Moran index,disaster risk is spatially clustered,and the high comprehensive risk index is mainly clustered in Zhumadian City,Zhoukou City and southeastern Pingdingshan Mountain;using the flood removal area index of Henan Province from 2000 to 2019 and combining with relevant studies for verification,the assessment results match the actual situation and are consistent with the results of other scholars’ studies The results of the ARIMA model-based prediction of the percentage of precipitation spacing from 2022 to 2024 show that the areas where heavy flooding is likely to occur in the future are mainly located in Wolong District and Wancheng District of Nanyang City,some areas of Xinyang City and the central city of Zhengzhou City.Combining the results of the comprehensive risk assessment and the forecast results,engineering recommendations are made for the high-risk areas,medium-high risk areas and forecast areas,and non-engineering recommendations are made for the whole province.