湘江流域洪水灾害综合风险评价

Integrated flood risk assessment of Xiangjiang River Basin in China

依据灾害系统理论,在综合考虑致灾因子、孕灾环境和承灾体的基础上,从致灾因子、孕灾环境的自然属性和承灾体的社会属性两方面出发,以县级行政单元为基本评价单元,进行了湘江流域洪水灾害的综合风险评价。在综合考虑降雨量、地形以及历史上洪水灾害发生频次等自然因素的条件下,利用地图代数分析得到了湘江流域洪水灾害危险性评价图;在综合考虑人口密度、耕地面积百分比、人均GDP和单位面积水库和塘坝容量等社会经济指标的基础上,利用模糊综合评判法得到了湘江流域洪水灾害脆弱性评价图。在此基础上采取“乘”模型的计算公式,即风险=危险性×脆弱性,将湘江流域洪水灾害风险划分为高风险、较高风险、中等风险、较低风险和低风险5个等级,并借助地理信息系统软件编制了湘江流域洪水灾害综合风险等级评价图。

Based on disaster system theory and using administrative county as basic assessment unit, flood risk assessment of Xiang River Basin is conducted in regards to natural properties of hazard and environment as well as socioeconomics of hazard-affected bodies. Using the map algebra function of the ARC/INFO system, a map of flood hazard assessment for Xiang River Basin is constructed by taking various natural factors, such as precipitation, topography and historic flood frequency, into consideration. With application of the fuzzy comprehensive evaluation model, a map of flood vulnerability assessment is also developed, where population density, agricultural land percentage, GDP per capita and capacity of small reservoirs are considered as the determining factors. Using the ＂Multiply＂ model, i.e. Risk = Hazard × Vulnerability, flood risk of the Xiang River Basin is acquired, which is then divided into five levels： very high, high, mediate, low, and very low. At last, this paper works out the map of flood risk assessment of Xiangjiang River Basin supported by GIS software.