北京城市副中心防洪风险研究

Study on flood control risk of Beijing Urban Sub-center

北京城市副中心规划防洪标准为100a一遇,其流域上游规划2座中型水库、50余处蓄滞洪区尚未建成,副中心周边防洪工程距离规划标准差距较大,导致副中心防洪安全难以保障。针对副中心来自上游的外来洪水压力大、区内防洪工程不达标等问题,采用一维、二维数学模型,分别对区域洪水风险、穿越副中心的北运河漫溢造成的淹没风险,以及副中心周边三条干流河道堤防不达标造成的防洪风险进行模拟计算和具体分析。结果表明:流域上游洪水不经有效拦蓄下泄后,将导致北运河干流100a一遇洪峰流量增加33%;同时,副中心周边三条河道均存在堤防安全风险。其中北运河发生100a一遇洪水时,即使区内宋庄蓄滞洪区建成启用,仍将有2590万m 3洪水从3 km无堤段漫溢,并淹没副中心核心区0.2~2 m深。风险研究结果还表明,一旦近期通州境内宋庄蓄滞洪区、温潮减河分洪道等规划工程建成后,将有效降低城市副中心的部分防洪风险。研究成果对保障副中心防洪安全的规划工程实施安排及防汛抢险安排具有重要指导意义。

The planning flood control standard in Beijing City Sub-center is once in 100 year.Current situation of the upper basin is the planned 2 medium-sized reservoirs and more than 50 flood storage areas in the upper reaches have not yet been built,the flood control projects in neighbouring regions also has not meet the standards.Flood control safety in sub-centre is difficult to guarantee.Aim at external flood pressure from upstream for sub-center and problems from substandard flood control works in the area,in order to analyze the flood risk of the sub-center of the city,adopt one-dimensional and two-dimensional mathematical model,simulation calculations and specific analysis the upstream flood risk,the risk of flooding caused by river overflows and risk of flood control caused by the non-conformity of the levees in the Beiyunhe River、Chaobaihe River and Yunchaojianhe River three main rivers respectively.The result shows that the upper mountains and tributaries of the river basin are heavily drained without effective containment and will lead to a 100 year flood peak flow increase of 33%.At the same time,There are embankment security risks in the three rivers around the sub-center,There are still overflows in the main river and extreme deficiency risks around the sub-center.When the Beiyunhe river encountered a flood in 100 years,Even if the Songzhuang flood storage and detention area is completed,there will still be flooding from the embankment and submerge the core area of the sub-cente 0.2~2 meters deep.Risk studies also show that,After the implementation of plans such as the Wenchao River Diversion in the Songzhuang flood storage and Songzhuang detention area in Tongzhou,Will effectively reduce some of the flood risk of urban sub-centers.The research results are of great reference to the flood control works arrangement and important guiding significance for flood prevention and rescue arrangemen of the sub-center.