| Summary: | 碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 104 === In recent years, flooding in urban areas have been occurring more frequently due to the increasing of extreme rainfall events. Therefore, assessment of high inundation potential areas in metropolises becomes very important. In the past, 2D flood inundation models are often used to simulate flooding areas owing to its accuracy. However, with their time-consuming property, they are usually used in advance to idetify high potential zones of flooding during non-disaster time and then the results are provided to disaster prevention works for reference.
Urban flooding surveys often use streets as division criteria. Therefore, this study attempts to develope a street flood inundation model for fast evaluation of street flooding. This model consists of three modules: (1) rainfall-runoff transformation, (2) 1D street flow routing, (3) 1D sewer flow routing. By changing the routing order of these three modules, two different rainfall collection methods including Method A: rainwater into storm sewers first and Method B: rainwater into street first, are proposed to evaluate potential flooding streets right after rainfall events occured.
In this study, Mucha drainage basin in Wenshan Distrinct, Taipei, is selected as the study area. Two short duration and one long duration rainfall events are used for simulation and analysis. Due to the closeness to real rainfall collection phenomena, the simulated results from Method B has a better agreement with the measured data of street inundation areas and sewer water levels whether the duration of rainfall event is short or long. Thus, we take method B as a representation of street flood inundation model. Compared to 2D flood inundation models, street flood inundation model has a better performance on computation time and may be used to evaluate the flooding disaster immediately.
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