基于InfoWorks ICM的北京市西城区排涝能力分析

Analysis of drainage capacity in Xicheng district,Beijing with InfoWorks ICM

为评估北京市西城区行洪排涝能力,基于InfoWorks ICM构建了北京市西城区精细化防洪排涝模型,洪峰流量和洪水总量的模拟误差范围分别为−16.7%~19.1%和−13.2%~6.9%.分析了不同降雨历时和雨型情景下,区域的管道排水能力、河道行洪能力,诊断了内涝原因.结果表明:西城区管网不足1 a一遇的管线长度占比为41%,排水能力较差;西护城河下游100 a一遇的最高水位距河岸约0.681 m,存在安全隐患;北护城河上游100 a一遇的最高水位距河岸约0.60 m,超过该河段警戒水位;100 a一遇长历时(24 h)暴雨情景下西城区城市内涝积水最大深度为1.710 m.通过研究,明确了西城区防洪排涝隐患主要集中于老旧平房、老旧楼房、棚户及混合等区,需要重点防范.研究结果可为西城区积水和内涝治理及管道提标改造提供数据支撑;结合地下空间分布及积水点位,可为西城区平急两用内涝蓄滞空间应急利用方案编制提供依据.

To evaluate flood control and drainage capacity in Xicheng district,Beijing,a refined flood control and drainage model is constructed with InfoWorks ICM.Simulation for peak flood discharge and total flood volume show error ranges of−16.7%~19.1%and−13.2%~6.9%respectively.Drainage capacity of pipelines and flood conveyance capacity of rivers under different rainfall durations and patterns are analyzed,and causes of urban flooding are diagnosed.Up to 41%of the pipeline network in Xicheng district has drainage capacity below 1-year return period,indicating rather poor drainage capacity.Maximum water level in downstream section of West Moat River under the 100-year return period is approximately 0.681 meters below embankment,indicating a potential safety risk.In upstream section of the North Moat River,maximum water level under the 100-year return period is about 0.60 meters,which exceeds the warning water level for that river section.Under a long-duration(24 hours)rainfall scenario with a 100-year return period,maximum water depth of urban flooding in Xicheng district reaches 1.710 meters.Therefore flood and drainage hazards in Xicheng district are primarily concentrated in areas with old houses,aging residential buildings,in shantytowns and mixed-use zones,which require focused attention.These findings will provide critical data support for flood and waterlogging management,and pipeline upgrades in Xicheng district.By integrating distribution of underground spaces and waterlogging points,these data provide ground for development of emergency plans for dual-use floodwater storage and retention spaces.