都會區街道與雨水下水道水流互動之快速淹水模擬

Fast Urban Flood Inundation Model for Simulating Dynamic Interaction between Street Networks and Storm Sewer Systems

梁益詮(Yi-Cyuan Liang)

指導教授 ： 張倉榮

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201602976

摘要

近年來因極端降雨事件增加，使得都市地區淹水事件頻傳，故評估都市高淹水潛勢地區變得相當重要，以往多以二維淹水模式來模擬淹水範圍，此模式雖然準確，但因計算耗時，通常只能在非災害發生期間預先模擬完多種降雨情境，找出易淹水區域，再提供防災工作之參考。
都市淹水調查常以街道作為區分範圍，因此，本研究發展一街道淹水模式來快速評估街道淹水狀況，此模式結合降雨逕流、一維下水道及一維街道等三種模組，並藉由改變模組的演算順序，可提出兩種雨水收集方法，分別為下水道收集(方法A)及街道收集(方法B)，並比較兩者在下水道水位及街道淹水之差異。
本研究以台北市文山區木柵次集水區為研究區域，並以兩場短延時事件及一場長延時事件進行模擬與分析，結果顯示，較符合真實雨水收集機制之方法B，無論是長、短延時事件，其下水道水位及街道淹水範圍之模擬結果皆較貼近實際調查狀況，則視其為本研究街道淹水模式的代表，並透過與二維淹水模式之比較，可發現街道淹水模式在計算時間上有較好的表現，或許可做為即時淹水災害評估之參考。

關鍵字

二維淹水模式 ； 街道淹水模式 ； 雨水下水道 ； 快速淹水模擬

並列摘要

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.

並列關鍵字

2D flood inundation model ； Street flood inundation model ； Storm sewer flow ； Fast flood inundation modelling

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