沿海城市潮、雨遭遇下内涝模型及应用

Research on Waterlogging Model of Coastal City Based on Encounter of Rainstorm and Tide

以海南省海甸岛为例,基于带有地表属性信息的高精度DEM地形网格,依据城市分区精细产流方法计算产流,以分段线性化方式拟合实际雨水管网排水能力曲线,并建立了排水能力与潮位新型函数关系式,将水陆边界条件处理为可双向过水的模型边界,最终将地表产汇流模块、地下管网水动力模块和潮(洪)水漫滩淹没模块三者耦合,建立沿海城市潮、雨遭遇内涝模型,探讨潮、雨遭遇情况下城市水情和涝情特征及差异。结果表明,潮、雨遭遇情景下城市内涝整体情况更加恶化,积水面积剧增;不同区域内涝恶化原因不同,临海区域主要是潮水倒灌引起,城区内部区域恶化主要是高潮位顶托下内水无法外排所致;对比单独降雨下,典型内涝代表点积水深度平均增加0.22 m,积水历时平均增加7.70 h,深度积水持续时间显著延长。

Taking Haidian Island in Hainan Province for an example,on the basis of urban fine partitioning runoff method for calculating runoff and rainwater drainage capacity curve fitted by piecewise linearization,the function relation of the drainage capacity and the tidal level was established by using high precision DEM terrain grid with surface attribution. Water land boundary condition was processed to allow water flow in both directions. Eventually waterlogging model of coastal city based encounter of rainstorm and tide was established by coupling flow concentration module with hydrodynamics of underground pipe network and tidal floodplain submergence. The characteristics of urban water regimen and waterlogging were discussed. The results show that the encountering of the tide and rain will make urban waterlogging situation worse,and water-logged area increased; deteriorative causes of urban waterlogging are not the same for different area,coastal area was mainly caused by the tidal water flow backward and the urban interior zone did not drain off water owing to high tidal level. Compared to independent rainfall case,water-logged depth of the typical representative points increase 0.22 m averagely,water-logged durations increase 7.7 hours averagely as well as the time of duration for deep waterlogging prolong obviously.