低影响开发设施组合下的城市雨洪调控情景模拟研究

Scenario simulation study on urban rain flood control under the combination of low impact development facilities

【目的】低影响开发(Low Impact Development,LID)作为一种新型雨洪管理方法,包括绿色屋顶、雨水花园、透水铺装等典型措施,对降雨径流有明显的控制作用,能够有效降低城市内涝隐患。【方法】以浙江省海宁市为例,基于暴雨洪水管理模型(Storm Water Management Model,SWMM),模拟不同重现期(1 a、5 a、10 a、30 a、50 a)、不同布设比例(20%,50%,100%)LID组合措施情景下的城市内涝过程,分析海宁市溢流分布情况、程度及其原因,探讨溢流区域LID组合措施对节点溢流、地表径流以及管网负载的影响。【结果】结果表明:在不同设计降雨情景下联合路、海昌路、水月亭西路、西山路以及隆兴港等地管网溢流较为严重;LID组合措施布设比例相同时,随着重现期的增加,LID组合措施对地表径流和节点溢流的削弱作用呈下降趋势,LID措施的作用趋于饱和状态;重现期为30 a和50 a、布设比例为50%时,地表径流的削减为45.92%和44.09%。【结论】LID组合措施对雨洪的控制作用有限,降雨强度对节点溢流、地表径流起主导作用。海宁市部分老旧小区管道年份较长,管径较短,管网溢流情况严峻,建议重点关注区域管网改造和LID措施空间布局。研究成果对于海绵城市建设规划、缓解城市内涝灾害具有一定参考价值。

[Objective]As a new rain flood management method,low impact development(low impact development,LID) includes typical measures such as green roof,rain Water garden,permeable pavement and so on.It has obvious control effect on rainfall runoff and can effectively reduce the hidden danger of urban waterlogging.[Methods]Taking Haining City,Zhejiang Province as an example,based on the rainstorm flood management model(Storm Water Management Model,SWMM),the urban waterlogging process was simulated under different return periods(1 a,5 a,10 a,10 a,50 a) and different arrangement ratios(20%,50%,100%) of LID combined measures,analysis of the distribution,degree and causes of overflow in Haining City.The effects of LID combination measures in overflow area on node overflow,surface runoff and pipe network load are discussed.[Results]The result show that the pipe network overflow is more serious in different design rainfall scenarios,such as Union Road,Haichang Road,Shuiyueting West Road,Xishan Road and Longxing Port.When the proportion of LID combined measures is the same,the weakening effect of LID combined measures on surface runoff and node overflow tends to decrease with the increase of return period.The effect of LID measures tends to be saturated,with a return period of 30 a and 50 a,and when the layout ratio is 50%,the reduction of surface runoff is 45.92% and 44.09% respectively.[Conclusion]The control effect of LID combination measures on rain flood is limited,and rainfall intensity plays a leading role in node overflow and surface runoff.In the case of extreme rainstorm,the influence of rainstorm on runoff and node overflow is dominant.The years of pipelines in some old residential areas in Haining City are longer,the diameter of pipes is shorter,and the overflow of pipe networks is serious.It is suggested that we should focus on the reconstruction of regional pipe networks and the spatial layout of LID measures.The research result have a certain reference value for sponge city construction planning and mitigation of urban waterlogging disasters.