基于GIS的江西省洪涝灾害风险评估

2010年夏季江西省发生多轮洪涝灾害,灾情十分严重。根据自然灾害系统理论,以江西省鄱阳湖流域地区为研究对象,从洪涝灾害的危险性、暴露性、脆弱性与防洪能力4个角度出发,选取降水、地形、水系、人口、经济、生态及圩堤等10个评价要素指标,采用90 m分辨率DEM、1960~2005年84个气象站点逐日降水量、2003~2008年江西洪涝灾情数据、2009年社会经济统计数据以及2005年江西省土地利用数据,以1 km单元格为基本评价单位,利用GIS空间分析与建模功能构建洪涝灾害风险评估指数模型,对江西省重大洪涝灾害进行综合风险评估。结果表明:该评估模型能成功应用于区域尺度,研究区洪灾风险分布呈现以江西北部的鄱阳湖湖区及蓄滞洪区为中心向两边递减的特点,从中心至外风险等级逐渐降低;从行政区划上,湖口、鄱阳、抚州、上饶等因地势平坦、降水量大、河网密集处于高风险区,而低风险区集中在降水少、地势高且山区分布较多、不易集水的江西南部,如:遂川、崇义等。经2010年6月17~25日发生的暴雨洪灾情况验证,该评价结果与实际情况相符,可为洪灾风险管理与决策提供科学依据。

RISK ASSESSMENT OF FLOOD DISASTER IN JIANGXI PROVINCE BASED ON GIS

In summer of 2010,there were several rounds of flood disaster in Jiangxi,and the disaster loss situation is serious.According to natural disaster system theory,taking Jiangxi as the focus area and using 1 km as basic assessment unit,from the four angels of the hazard,exposure,vulnerability and disaster prevention of the flood disaster,we chose the indices of terrain,precipitation,river,population,economy,ecological environment and embankment to assess flood disaster risk in Jiangxi Province.In this paper,DEM with 90 m resolution,daily precipitation data during 1960 to 2005,disaster date during 2003~2008,socio-economic data in 2009 and land use map in 2005 were processed by the functions of spatial analysis and model building.From the result,the assessment model could be successfully applied to regional scale.Flood risk had a center distribution around the Poyang Lake region in the northwest of Jiangxi.And the risk declined gradually from center to the periphery.From administrative divisions,the highest risk regions were located in Hukou,Poyang,Fuzhou,and Shangrao etc,because these region were flat,had dense river network and large precipitation.Whereas the lowest flood risk areas were located in Shuichuan and Chongyi,because they were mainly in the region of less precipitation,high altitude and being hard to catchment.Using the flood hazard during June 17-25th,2010 to test and verify,the evaluate solution was consistent with the actual situation.