城市极端暴雨涝情变化特征模拟分析——以宁夏固原市为例

Simulation on variation characteristics of urban extreme rainstorm and waterlogging:case of Guyuan City,Ningxia Autonomous Region

为探究极端暴雨条件下城市涝情的变化特征,应用二维水动力模型(GAST模型),对宁夏固原市主城区开展多暴雨工况下的积水模拟分析。采用2017年7月27日实测降雨数据对模型进行验证,经验证模型精度满足要求。基于研究区高精度地形数据、土地利用数据和实测数据,对12种短历时设计暴雨条件下的城市内涝时空变化过程进行模拟。模拟结果表明:随着降雨量的增加,道路积水面积及积水总量峰值均随之增大,但积水面积峰值增加趋势逐渐趋于平缓,积水总量峰值与之相反,增加趋势逐渐增大;降雨量越大,风险最大的Ⅳ级内涝积水面积及积水总量峰值增加趋势越明显,尤其在降雨量大于100 mm后,其增加趋势更加显著。研究成果揭示了固原城市极端暴雨下的内涝积水变化过程,对合理应对城市防洪排涝等方面具有借鉴意义。

In order to explore the variation characteristics of urban waterlogging under extreme rainstorm conditions,the 2-D hydrodynamic model(GAST model)was used to simulate the waterlogging in the urban area of Guyuan City,Ningxia Autonomous Region.First,the measured rainfall data on July 27,2017 was used to verify the model,and it was proved that the accuracy of the model met the requirement.Based on high accuracy terrain data,land use data and measured data,the spatial and temporal process of urban inundation under 12 short-duration designed storm conditions were simulated and their flooding risks were analyzed.The results show that with the increase of rainfall,the peak total inundation area and water volume on road all increased,but the increasing trend of peak inundation area gradually tended to level off while the trend of peak total water volume gradually increased;the greater the rainfall,the more obvious the increasing trend of peak inundation area and total water volume of the highest risk level IV,especially after the rainfall was greater than 100 mm.This study reveals the change process of inundation under extreme rainstorm in Guyuan City,which has significance for reasonable dealing with urban flood prevention and drainage.