为分析地表径流速度对城市内涝的影响，采用一维地下排水管网与二维城区地形的动态耦合模型，选取大连市某排水区块作为研究区域，设置4种地表径流速度10种设计降雨场景，模拟分析在不同重现期设计降雨及不同地表径流速度下研究区的内涝积水特性。结果表明：随着地表径流速度降低，管道排水压力变小，管道排水达标率最高可提升48.05%，且降雨重现期越短，地表径流流速对管道排水压力的削减效果越明显；地表径流流速对检查井溢流量影响显著，随着地表径流速度降低，检查井溢流量峰值最高可减小2 750 m3，峰现时间最长可滞后56 min，同时随着降雨重现期增长，地表径流流速对检查井溢流量的削减效果减弱；研究区低、高风险区淹没面积随地表径流速度降低，最高可分别减小1.64万、8.37万m2，但中风险区淹没面积变化反复。

To analyze the impact of surface runoff velocity on urban flood inundation,the dynamic coupled model is applied to generate the flood inundation map of a typical area in Dalian.The characteristics of flood inundation are compared and analyzed under several combinations between surface runoff velocities and return periods of design rainfall.A series of surface runoff velocity schemes are set up to simulate the dynamic process of flood inundation given different return periods of design rainfall,and also to quantitatively analyze the influence of surface runoff velocity on flood inundation,which provides support for urban flood analysis as well as flood disaster prevention and control. The one-dimensional pipe network model consists of 181 manholes,4 outlets,193 drainage pipelines and 181 sub-catchments.The largest and minimum area of sub-catchments is 2.29×10.4 m2 and 116 m2,respectively.The two-dimensional terrain model is divided into 4 032 rectangular grids with a grid size of 15 m×15 m.The surface runoff velocity is set to be 0.02 m/s,0.05 m/s,0.1 m/s and 0.3 m/s.40 simulation schemes are generated in combination with ten types of rainfall return periods.The pipeline pressure state is evaluated by the pipe filling,and the water accumulated over the study area is evaluated by manhole overflow.The risk of flood inundation is divided into three levels,namely,high-,medium-,and low-risk areas. The results show that the drainage load of the pipeline becomes smaller and the qualified rate of the pipeline becomes higher with the decrease of surface runoff velocity under the two-hourly design rainfall.And the qualified length and rate can be increased by 4.7 km and 48.05% with the decrease of surface runoff velocity.Moreover,surface runoff velocity has a significant influence on the volume of accumulated water.When the surface runoff velocity decreases,the peak value of accumulated water volume becomes smaller,and the delay of peak time is longer.The reduction effect of accumulated water is weakened with the increase of rainfall return period.With the decrease of surface runoff velocity,the peak value of total accumulated water can be reduced by 2 750 m3 at most,and the peak time can be delayed by 56 min at most.Meanwhile,under the 24-hourly design rainfall,the area of low-risk and high-risk areas decreases largely as the surface runoff velocity decreases.With the decrease of surface runoff velocity,the areas of low-risk and high-risk areas can be reduced by 1.64×10.4 m2 and 8.37×10.4 m2,respectively,while the area of a medium-risk area changes irregularly. The main conclusions are as follows: The surface runoff velocity has a significant impact on urban flood inundation.It affects the degree of urban flood inundation by changing the drainage load of the pipeline,the amount of ponding,and the area of the risk area.Overall,the decrease of surface runoff velocity,the harm of urban flood inundation is smaller.The relevant conclusions can provide decision-making references for relevant workers.