基于AHP-GIS的重庆市山洪灾害风险区划研究

山洪灾害风险评估与区划是山洪风险管理和决策的重要依据，可有效指导山洪灾害防治工作。利用重庆市2013~2015年山洪灾害调查评价数据，融合降雨条件、下垫面、人口条件、经济财产等多元参数，嵌入抗灾能力修正系数，建立重庆市山洪灾害风险性评价指标体系。利用层次分析法(AHP)确定各指标权重，并依托ArcGIS空间分析叠加功能得到重庆市山洪灾害危险性、易损性、风险性分布图。经多目标图层综合叠加与非监督聚类分析，将境内山洪灾害风险强度分为微、低、中、较高、高5个等级，其面积比例分别为14.97%、25.19%、24.41%、22.2%及13.23%。据此，将重庆市山洪灾害风险划分为渝东北高海拔山地较高风险区（1.42 km²）、渝东北中海拔山地中低风险区（1.12 km²）、渝东南中海拔山地高风险区（1.69 km²）、渝中部低海拔山地低风险区（2.07 km²）、渝西中低丘陵低微风险区（0.59 km²）及渝西低丘平坝较高风险区（1.34 km²）6个分区，风险度分布与分区结果客观反映了山洪灾害发生特点、分布情况、易发程度和防治迫切程度的区域差异。

Regionalization of Torrential Flood Disasters in Chongqing Based on AHP-GIS

The risk assessment and regionalization of torrential flood disasters are the important basis for the management and decision-making, which could provide effectively guidance for the prevention and control of torrential flood disasters. According to investigation and evaluation project of torrential flood disasters from 2013 to 2015, the risk assessment indexes were established in consideration of rainfall conditions, underlying surface, population conditions, economic property and other multiple parameters and corrected by disaster resilience. With the weight of each indexes determining by the Analytic Hierarchy Process (AHP), the hazard, vulnerability, risk distributions map of torrential flood disasters in Chongqing were overlaid by the means of ArcGIS. Through the multiple target layer composite overlay and non-supervised cluster analysis, the risk distributions map was divided into five categories: micro risk, low risk, medium risk, medium to high risk, and high risk with the area ratios 14.97%, 25.19%, 24.41%, 22.2% and 13.23%, respectively. Accordingly, the torrential flood disasters in Chongqing was divided into six areas: the medium to high risk zonation in the northeastern high altitude mountainous regions (1.42 km²), the low to medium risk zonation in the northeastern medium altitude mountainous regions (1.12 km²), the high risk zonation in the southeastern medium altitude mountainous regions (1.69 km²), the low risk zonation in the central low altitude mountainous regions (2.07 km²), the micro to low risk zonation in the central low hill regions (0.59 km²) and the medium to high risk zonation in the west hill-flatland regions (1.34 km²), which objectively reflected the regional differences of the torrential flood disasters characteristics, distribution, proneness, and urgency.