基于GIS的大连市暴雨洪涝灾害综合风险评估

Comprehensive risk assessment of rainstorm-flood disaster in Dalian City based on GIS

利用大连市日降水数据和社会经济数据,采用层次分析法(AHP)和熵权法,结合GIS技术,从暴雨洪涝灾害的危险性、暴露性、脆弱性和防灾减灾能力4个因子入手,选取18个暴雨洪涝灾害综合风险评价指标建立大连市暴雨洪涝灾害综合风险评估模型,对大连市暴雨洪涝灾害的综合风险进行评估。结果表明:从暴雨洪涝灾害危险性空间分布来看,大连市具有东北部、西南部地区较高,中部地区较低的特点;北部地区暴雨洪涝灾害暴露性和防灾减灾能力均较低,而南部区域较高;西南部、中部地区暴雨洪涝灾害脆弱性较高,东北部、南部地区脆弱性较低。大连市暴雨洪涝灾害综合风险等级以中风险为主,占全市总面积的41.3%,从大连市的东北到西南方向呈片状分布;其次是低风险区,占全市总面积的20.93%,主要分布在庄河市的西北部和瓦房店市;高风险区域面积小,仅占全市总面积的0.72%,集中分布在沙河口区和长海县。沙河口区和长海县作为大连市暴雨洪涝灾害的高风险区,在极端暴雨条件下极有可能发生洪涝灾害,已成为防洪工作的重点关注地区。

Taking the Dalian City as the research area,based on the GIS technology,the analytic hierarchy process(AHP)and entropy weight method(EWM)were introduced to evaluate the comprehensive risk of rainstorm-flood disaster by using the daily precipitation data and socio-economic data of the Dalian City.18 indicators in the risk assessment of rainstorm-flood disaster were selected to build the comprehensive risk assessment model of rainstorm-flood disaster in Dalian City from four factors,consisting of the hazard,exposure,vulnerability and emergency response&recover capability.The results of comprehensive risk assessment showed that the spatial hazard distribution of rainstorm-flood disaster in Dalian City has the characteristics of being higher in the northeast and southwest and lower in the middle.The exposure and emergency response&recover capability of rainstorm-flood disaster were lower in the northern Dalian,but higher in the southern Dalian.The vulnerability of rainstorm-flood disaster was higher in the southwest and central Dalian,while that was lower in the northeast and southern Dalian.The comprehensive risk grades of rainstorm-flood disaster in Dalian City were mainly medium risk,accounting for 41.3%of the whole study area,and they were distributed in patches from the northeast to the southwest.The low risk areas,accounting for 20.93%of the total area,were mainly distributed in the northwest of Zhuanghe and Wafangdian,while the high-risk areas were small,only accounting for 0.72%of the whole area,in the Shahekou District and the Changhai County.As the high-risk areas of rainstorm-flood disaster in Dalian City,they are extremely likely to encounter the flood disaster under extreme rainstorm conditions and have become key areas for the flood control with more attentions.