基于GIS的重庆市洪灾综合风险评估研究

On Flood Risk Assessment and Division in Chongqing Based on GIS

洪涝灾害作为自然灾害的重要险种之一,严重影响了人类的生产生活.根据自然灾害风险评估理论,以重庆市为研究对象,从洪灾危险性、敏感性和易损性3个角度出发,选取降水、地形、植被指数、单位面积GDP等8个评价要素指标,以县级行政区划作为评估单元,利用GIS空间分析功能对重庆洪灾进行综合风险评估,结果表明,洪灾危险性、敏感性和易损性均表现出较为明显的空间地域特征,危险性呈由西向东逐级递增的特点,峰值集中在渝东南和渝东北的两翼地区;受地形、河网密度和植被指数综合影响,洪灾敏感性指标分布与长江干流流向体现出了高度的空间相关性,峰值集中在长江干流沿岸的永川、江津、江北、涪陵、垫江等区县;而易损性指标则基本上与重庆市社会经济发展空间分布相吻合.综合来看,研究区洪灾风险等级整体呈现出由西向东减小的趋势,经济较发达的主城、渝西地区风险等级较高,经济欠发达的渝东南、渝东北地区风险等级较小.

As one of the important natural disasters,flood disaster has taken great influence on people＇s production and life.Based on disaster system theory,flood risk assessment is conducted in regards to flood hazard intensity,sensitivity and vulnerability.With Chongqing administrative as the search subject,8 evaluation factors,such as precipitation,terrain,vegetation index,GDP and so on have been taken,with county as an evaluation unit,comprehensive risk assessment of flood disaster in Chongqing based on GIS spatial analysis.The results show that the flood disaster hazard intensity,sensitivity and vulnerability all show obvious spatial and geographic characteristics,and flood disaster hazard intensity shows an increase from west to east,of which the peaks concentrate in the southeastern and northeastern flanks area.Affected by topography,river system,vegetation index,distribution of flood disaster environment sensitivity reflects highly spatial correlation with Yangtze River flows,of which the Peaks concentrate in the areas along the coast of Yangtze River,like Yongchuan,Jiangjin,Jiangbei,Fuling Dianjiang and so on;flood disaster vulnerability indicators have the same spatial distribution with the social and economic development of Chongqing.In general,flood disaster risk level in the study area overall shows a decreasing trend from west to east.Risk level in the economically developed downtown areas and west region of Chongqing is higher,while it is lower in the underdeveloped parts in southeast and northeast of Chongqing.