基于Logistic模型的四川山洪流域危险性评价

Risk Assessment of Sichuan Mountain Flooding based on Logistic Model

为对四川山洪灾害的危险性分布进行研究,利用山洪危险点、历史灾害点和相关的地形、植被和土壤等因子,采用二元Logistic回归方法,建立四川小流域山洪危险性评价模型,并根据模型计算得出四川各流域的山洪危险性评价结果。结果表明:山洪灾害的因子按重要程度由高到低依次为土壤的汇流系数、地形起伏度、流域圆度、平均植被指数和水流累计量。而各因子中,除土壤的汇流系数与山洪灾害的暴发成正相关,其余均为负相关;四川山洪灾害风险划分为风险低、风险较高、风险高和风险很高4类,各风险类型所占全省面积比例分别为47.05%、11.34%、16.19%和25.39%。其中,四川山洪灾害高风险地区主要分布在盆周山区、凉山州和攀枝花地区,分布范围较广。低风险区为四川盆地、甘孜北部和阿坝北部。

In order to study the risk distribution of flash floods in Sichuan,we first collected factors such as danger points,historical disaster points of flash flood flash flood danger points,flash flood historical disaster points,and terrain,vegetation,and soil related to flash flood disasters.Then using binary logistic regression method,a model of flash flood risk assessment of small watershed in Sichuan was established and the results of flash flood risk assessment in Sichuan Basin were calculated based on the model.The results show that:Among the factors of the flash flood disasters in Sichuan,they are ranked in order of importance:soil confluence coefficient,topographic relief,watershed roundness,vegetation index,and water flow accumulation.And except that the soil confluence coefficient is positively correlated with the mountain flood disaster,others are negatively correlated;Sichuan mountain flood disaster risks are divided into four categories:low,medium,high,and higher.The proportions of each type of risk in the province are 47.05%,11.34%,16.19%,and 25.39%.Among them,the high-risk areas of mountain flood disasters are mainly distributed in the basin-mountainous mountainous areas,Liangshan Prefecture and Panzhihua area,with a wide range of distribution.The low-risk areas are the Sichuan Basin,northern Ganzi,and northern Aba.