江西省小流域山洪因子敏感性分析与灾害风险评估

Flash Flood Factors Sensitivity Analysis and Disaster Risk Assessment in Jiangxi Province

江西省山洪灾害频发,造成严重的社会经济损失和大量人口伤亡,定量表征各因子对山洪灾害的影响以及评估山洪灾害风险的空间分布,对山洪灾害的预警体系建立及重点防范区域确定具有科学参考价值。本文研究以江西省小流域为基本单元,从危险性、承灾体和易损性三个方面选取共计36项因子,利用主成分分析(principal components analysis,PCA)最终筛选出12个关键因子。基于关键因子,使用确定性系数(certainty factor,CF)、多因子叠加权重计算,结果表明:易损性因子对山洪灾害风险的相对贡献较大,危险性因子中汇流时间为1.15~2.20 h、坡度为11°~22°、年最大6 h降雨量均值小于81.02 mm时和6 h设计暴雨变差系数小于0.42,为山洪灾害风险的敏感区,承灾体因子对山洪灾害风险的相对贡献较小。江西省较大风险以上小流域占比为25.47%,其中东北部的饶河、西南部的修水、中部抚河流域和信江上游、西南部的赣江上游山洪灾害风险大,尤以景德镇、上饶市和赣州市为甚,鄱阳湖流域及西南和西北部的修水流域山洪灾害风险小。

Flash floods occur frequently in Jiangxi province,causing serious property losses and human casualties.In order to measure the influences of the factors on flash flood risk and to evaluate the spatial distribution of flash flood risk based on small catchments in Jiangxi Province.This is a scientific reference for the establishment of early warning systems for flash floods and the identification of critical preventative areas.According to the theory of flash floods disaster system,selecting 36 factors from three aspects:hazard,risk-bearing body and vulnerability.Principal component analysis(PCA)selects 12 key factors.Using the certainty factor(CF)method,multi-factor superposition weight,it is findings that the vulnerability factors have the greatest influence on the occurrence of flash floods:the time of concentration range is 1.15~2.20 hours,the slope range is 11~22 degrees,the average annual maximum 6-hour rainfall is less than 81.02 mm,and the variation coefficient of the 6-hour design rainstorm is less than 0.42.The relationship between the risk-bearing body factors and the flash flood risk is not obvious.The areas of small watersheds with more than higher risk are 25.47%.The northeast Raohe river basin,the southwest Xiushui basin,the center Fuhe basin and upper Xinjiang river,and the southwest upper Ganjiang river are all at high risk of flash floods,especially in Jingdezhen,Shangrao and Ganzhou city.Low risk of flash floods in southwest and northwest areas of Xiushui basin and the Poyang Lake basin.