暴雨内涝危险性情景模拟方法研究——以上海中心城区为例

Research on the Scenario Simulation Method of Rainstorm Waterlogging Hazard: A Case Study in the Central Urban Area of Shanghai

本文采用地理信息系统技术(GIS)与水文/水动力学相结合的方法,使用修正的SCS模型进行产流模拟,利用局部等体积法和水动力模型进行汇流模拟,建立了基于情景的城市暴雨内涝危险性模拟工具,并对相同雨强情景下不同汇流模型的模拟结果与精度进行了对比分析。结果表明:(1)局部等体积法计算简单,对降雨的时程分配较为敏感,峰前历时和雨强对结果影响显著,较适合于雨型确定的城市暴雨内涝危险性快速模拟;水动力模型计算复杂,与整个降雨历时存在明显关系,模拟精度较高。(2)利用台风"麦莎"带来强降雨导致的积水实测数据,对模拟结果进行对比和验证,表明本文建立的水动力模型法模拟结果与实测降雨积水更为接近,更适合上海中心城区暴雨内涝危险性情景模拟。

For the purpose of simulating rainstorm waterlogging scenarios in the urban areas that have specific terrain surface characteristics, a comprehensive methodology derived from the hydrology/hydrodynamic theory and the geographic information system（GIS） is proposed in this paper. Moreover, a modified SCS model is utilized for the runoff producing simulation, while a locality volume equation and a hydrodynamic model are used for runoff converging simulation. Taking the central urban area of Shanghai as an example, rainstorm scenarios with 100-year return period are designed for the simulation. Meanwhile, based on the same runoff producing process, the locality volume equation and hydrodynamic model are used to simulate the waterlogging course respectively. Thereafter, a comparison is made to reveal the distinction of accuracy among the results acquired from these diverse models.The results indicate that：（1） it is easier for the runoff converging calculation to use the locality volume equation, but the results are obviously influenced by the temporal distribution of the rainfall course, especially at the period before the peak, as well as by the intensity, thus this model is more feasible for fast waterlogging simulation if the rainfall pattern is determined in advance. As for the hydrodynamic model, the runoff converging calculation is more complicated, but shows a better performance and higher precision when being used for simulating a longer rainfall process. Furthermore, the results have a closer relationship with the rainfall duration.（2） Specifically, these two models are verified based on the inundation data measured during the typhoon＂Matsa＂. A comparison between the simulation results and the historical data predicts that, although more or less a deviation is inevitable, the hydrodynamic model performs better in fitting the characteristics of urban rainstorm waterlogging, thus basically it＇s found more suitable for simulating the waterlogging hazard in the central urban area of Shanghai.