基于城市内涝仿真模型的天津风暴潮灾害评估

Tianjin Coastal Storm Surge Disaster Assessment Based on Urban Waterlogging Simulation Model

基于城市内涝仿真模型,根据天津沿海地区的地形、地貌特征以及排水系统等对城市内涝仿真模型进行改进,在沿海边界和河口设置时变水位,使得模型拓展到既能模拟暴雨产生的内涝,也能模拟由于风暴潮侵袭造成的淹没情景。该模型对天津沿海地区历史上典型风暴潮个例以及10年、20年、50年、100年一遇重现期风暴潮产生的积水范围和积水深度进行了模拟,并对2012年8月3日台风达维(1210)造成的天津沿海风暴潮进行了业务试应用。将历史风暴潮个例模拟结果以及2012年8月3日的评估结果与实际灾情进行对比,结果显示模型具有较好的模拟能力,可应用于风暴潮灾害的评估和预估业务中,为相关部门和行业提供决策参考。

Most waterlogging models for inland city use a single boundary condition, the boundary is usually set in a small or large river, with a single flow direction towards outside the region, or set on a highway or a large dam without water exchange alternatively. However, for coastal areas, the ebb and flow lead to changes in wet and dry. Adapting to the intertidal nature, the model should involve dealing with dynamic boundary. Based on urban waterlogging simulation model, the topography and geomorphology of Tianjin coastal areas, as well as the pipe network and drainage systems, are used to expand and improve Tianjin urban waterlogging simulation model. Dynamic water level is set at the coastal border, and the water level stands for the tidal level. When the tide level is higher than the coastal embankment, the tide floods into the city and causes waterlogging. Therefore, the model simulates not only rainfall waterlogging but also the submerging scenario due to storm surge invasion. The flooding scope and standing water depth are simulated using the redeveloped model for the historically typical storm tidal cases in the coastal areas of Tianjin. Referred with the collected records of disaster and actual survey, the developed model takes on skills to some extent in simulation of the submerged scenario due to storm surge invasion. Differences between the simu- lation and the historical records, however, are non-intentionally increased by using the latest ground eleva- tion data. This approach is used in operational application for simulating the storm surge caused by Typhoon Damrey on 3 August 2012. The simulated flooding scope and site are closed to the actual scene, but the simulated standing water depth is larger. Much more detailed calibration should be done in future. Furthermore, the submerging scenarios caused by storm surge in several return periods are simulated. These simulations can be directly used in projecting and assessing the submerging scenario if there is a storm surge predicted to be an N-year return-level or if it has occurred. These simulations can also be directly reported to the government and business clients for early warning.