基于层次分析法的北京城市副中心内涝风险评估

Risk assessment of waterlogging in Beijing Municipal Administrative Center by hierarchical analysis

基于"危险性-暴露性-脆弱性"的内涝风险评估框架,采用层次分析法构建了北京城市副中心内涝风险评估体系,运用模型模拟法、GIS空间分析法等多种方法获取评估指标值,对研究区进行了10、20、50 a一遇降雨情景下的内涝风险评估.研究结果表明:1)副中心现状排涝能力基本满足10 a一遇降雨,距离规划50 a一遇的排涝标准有较大差距;2)中高风险区主要集中在北运河以西、通惠河以南的原通州老城区,运潮减河以北、小中河以东的区域,以及京秦铁路沿线路段的下凹桥区;3)积水危险性与内涝风险度结果并不吻合,内涝风险度评价结果更为科学,也更具指导性.建议对高风险区采取"一点一策"的方式制定应急预案,提升副中心洪涝预报预警能力.

Flood risk assessment framework of“risk-exposure-vulnerability”was adopted to construct a flood risk assessment system for the Beijing Municipal Administrative Center by hierarchical analysis,index values were obtained by model simulation,GIS spatial analysis and other methods.Risk assessment of waterlogging in the study area was carried out under the scenarios of rainfall once every 10,20 and 50 years.The current drainage capacity of the Municipal Administrative Center was found to meet the requirement of rainfall once every 10 years only,far from the planning standard of once every 50 years.The middle and high risk areas were found concentrated in the former old towns of Tongzhou west of the North Canal,south of the Tonghui River,area north of the river,east of the Xiaozhong River,and the lower concave bridge area along the Beijing-Qin Railway.The risk degree of ponding was inconsistent with risk degree of waterlogging,evaluation of waterlogging risk seemed more scientific and instructive.The“one site,one policy”strategy should be adopted to formulate emergency plans in high risk areas to improve flood forecasting and early warning capabilities.