中小城市排水系统排水能力和内涝特性分析——以涡阳县为例

Analysis on draining capacity of drainage system and waterlogging characteristics of small and medium-sized cities——a case of Guoyang County

随着城市化进程的加快,城区不透水面积逐渐增加,大多数中小城市的排水管网建设标准相对滞后,中小城市面临严重的内涝风险,研究城区产汇流特性对于城市内涝防治具有十分重要的意义.本文以涡阳县南城区为研究对象,首先利用临近地区水文资料、高精度的遥感影像和DEM共享数据,借助ArcGIS平台和SWMM开源软件,通过综合径流系数法对模型进行率定,并从综合径流系数、降雨径流产汇流关系和实测降雨产生的积水深度对模型进行验证,分析研究区典型暴雨下的管网满管和积水情况,评估排水系统的排水能力和城区的内涝风险.然后,对内涝严重区域进行有针对性的内涝分析,并分析低影响开发措施对城区内涝的影响.结果表明:(1)排水系统在暴雨降雨重现期0.5a及以下,基本可以满足排涝要求;排水系统在暴雨降雨重现期1a及以上,均不能满足排涝要求.(2)低影响措施对城区内涝有很好的缓解作用.该研究方法可为资料缺乏地区,尤其是中小城市内涝分析和防洪减灾提供参考.

Following with the acceleration of urbanization and the gradual increase of impervious area in urban area due to the relative lag of the construction standards of the water drainage pipe-network for most of the small and medium-sized cities,and then serious waterlogging risks are faced with them,thus the study on the runoff yield and confluence characteristics of urban area is quite important for the urban waterlogging control and prevention.The south urban district of Guoyang County is taken as the study object,and the model is calibrated at first with the hydrlogical data,high-precision remote sensing image and the shared data of DEM of the adjacent areas through the method of integrated runoff coefficient by means of ArcGIS platform and the open source software-SWMM,while the model is verified with the integrated runoff coefficient,the rainfall runoff-confluence relationship and the measured waterlogging depth caused by rainfall;from which the conditions of full-pipe of pipe-network and waterlogging in the areas with serious waterlogging under typical rain storm in the study area are analyzed and the draining capacity of the drainage system and the waterlogging risk in the urban area are evaluated.Afterward,a targeted analysis on the waterlogging in the areas with serious waterlogging is made and the impact from the arrangement of the low-impact development(LID)measures on the urban area is analyzed as well.The study result shows that(1)the drainage system can basically meet the waterlogging drainage requirement under the conditions of the rainstorm return period of 0.5 years and below it,while the drainage system cannot meet the waterlogging drainage requirement under the condition of the rainstorm return period of 1 year and above it.(2)The low-impact development(LID)measures have better effects to mitigate the waterlogging in urban area.The study method proposed herein can provide a reference for the urban waterlogging analysis and flood control and disaster mitigation of the data-deficiency region,especially small-and medium-sized cities.