外江水位及雨峰系数对典型城市片区内涝的影响规律研究

Research on the Influence Law of Water Level in Outer Rivers and Rainfall Peak Position Coefficients on Typical Urban Waterlogging

外江水位及降雨雨峰系数是影响城市内涝严重程度的重要因素,因此探究其影响规律对内涝机理分析及内涝防治具有重要意义。以典型城市片区为例,建立管网、河道和地表相耦合的城市内涝模型,并计算2种外江水位组合3种雨峰系数共6种工况下的片区内涝情况,定量分析外江水位及雨峰系数对内涝的影响,在此基础上提出缓解城市内涝的方法策略。结果表明:外江洪水对场坪高程与洪水位接近且地势平坦的区域影响较为显著;内涝风险等级越高,外江水位增高后淹没面积增长率越大;在相同降雨强度下,雨峰越靠后内涝淹没情况越严重;需从流域整体出发综合上下游措施以有效减轻内涝灾害。研究可为认识城市内涝规律和内涝治理提供思路和借鉴。

Water level in outer rivers and rainfall peak position coefficients are important factors affecting the severity of urban waterlogging.Therefore,exploring their influence law is of great significance for mechanism analysis and prevention of waterlogging.In this study,a typical urban area was taken as an example to establish the urban waterlogging model coupled with a pipe network,river channel,and surface.Then,the model was used to calculate the waterlogging risk of the area under six situations derived from two conditions of outer river water level and three conditions of rainfall peak position coefficients.Then,the influence of outer river water level and rainfall peak position coefficients on urban waterlogging was quantitatively analyzed.On this basis,corresponding strategies to alleviate urban waterlogging were proposed.The results show that the water level in outer rivers has a significant effect on flat urban areas whose elevation is close to the water level in outer rivers.The higher risk level of waterlogging indicates a higher growth rate of inundated areas after the water level in the outer river increases.In the same rainfall intensity,the lower rainfall peak position coefficient indicates more serious waterlogging.Therefore,comprehensive upstream and downstream measures should be taken from the holistic view of watersheds to effectively reduce waterlogging disasters.This study provides ideas and references for understanding the law of urban waterlogging and coping with waterlogging.