臺北南區暴雨淹水調適策略與效益之研究

Study on the Strategy and Benefit of Adjusting Storm inundation in Southern Taipei.

黃貫鈞(Kuan-Chun Huang)

指導教授 ： 李天浩

國立臺灣大學/工學院/土木工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201803574

摘要

全球暖化、都市熱島效應、極端強降雨變得更強，未來都會區內水滿管溢淹會成為新常態。國內外防洪防澇策略選項，諸如水利署的「出流管制、逕流分擔」，歐美等中緯度國家以入滲為主的低衝擊開發(Low Impact Development, LID)，內政部《建築技術規則建築設計施工編》所規範的建築基地「貯集滯洪設施」體積，《臺北市基地開發排入雨水下水道逕流量標準》要求的「流出抑制標準」等，在都市或區域尺度範圍發揮的功能和效益，以期打造臺灣都市成為不怕內澇淹水的「韌性城市」，是本研究擬探討的主要課題。
面對暴雨淹水頻率和量體增加，以臺北市為例，改善內澇淹水問題的主要困難包括：1.雨水下水道更新傷財、擾民、困難，2.暴雨強度和總量大於中緯度國家，3.都市已經建成，建地幾乎飽和，綠地空間有限，低衝擊開發策略削減高重現期暴雨逕流峰值的效益偏低或無效。本研究考慮臺北市現況和治理困境，提出三項工程策略和一項應變策略：1.疏導策略：道路導排；2.海綿策略A：公共用地和建地開放空間提供滯洪體積，吸納道路超額淹水；3.海綿策略B：(更)新建基地提供「貯集滯洪體積」，上、中游「抑制流出」和，下游「吸納道路超額淹水」；以及4.防禦策略：建築物施作擋水閘板，政府「研發都市淹水潛勢即時預報系統」，提前30分鐘通知淹水潛勢區民眾，佈設擋水閘板。本研究採用EPA-SWMM做為模擬工具，以臺北市大安區為例，評估前3項策略組合的效益；防禦策略可以根據案例模擬的淹水深度，補助民眾裝設擋水閘板。
選擇容易發生局部溢淹的臺北市大安區為例，利用設計降雨和實際的事件降雨，模擬探討道路導排、開放空間滯洪、阻止淹水入侵策略組合對於淹水深度降低、衝擊減輕效果。其中，道路導排設計可以降低約60%的最大淹水深度，再加入開放空間滯洪和10％面積的78mm「貯集滯洪設施」，可降低約70%的最大淹水深度。模擬案例發現：若沒有道路導排，淹水無法擴散、容易局部積淹，淹水深度偏大；若沒有滯洪體積，淹水無法減量，只是轉移下游、反而會加劇下游淹水；在臺北市大安區使用道路導排、滯洪體積策略後，短延時強降雨引發的內水淹水，已不至於會入侵地下空間和建築物。最後，在實施道路導排、貯集滯洪設施、公共空間滯洪策略以前，建議未來發展淹水潛勢預報，提前約30分通知個人、社區等，佈設擋水閘，熱帶海島型氣候的臺灣都市，才能真正成為不怕內澇淹水的韌性城市。

關鍵字

道路導排 ； 澇水貯留 ； 滯洪設施 ； SWMM ； 淹水管理

並列摘要

Global warming, urban heat island effect, and extreme heavy rainfall have become stronger, and flooding of water in the future will become the new normal. Domestic and international flood control and flood control strategy options, such as the “Outflow Control and Runoff Sharing” of the Water Resources Department, Low Impact Development (LID), which is mainly infiltrated in mid-latitude countries such as Europe and the United States, and the construction base regulated by the Ministry of the Interior. The volume of the "stagnation of flood detention facilities", the "outflow suppression standard" required by the "Taipei City Base Development and Discharge Standards for Rainwater and Underwater Channels", etc., functions and benefits at the urban or regional scale, with a view to creating a Taiwanese city that is not afraid of flooding The "resilient city" is the main topic to be explored in this study.
In the face of heavy rain flooding frequency and volume increase, taking Taipei City as an example, the main difficulties in improving flooding problems include: 1. Rainwater and underwater waterway renewals hurt money, disturb people, and difficulties. 2. Rainstorm intensity and total amount are greater than those in mid-latitude countries. 3. The city has been built, the construction site is almost saturated, the green space is limited, and the low-impact development strategy to reduce the peak value of the high-recurrence storm runoff is low or ineffective. This study considers the current situation and governance dilemma of Taipei City, and proposes three engineering strategies and a contingency strategy: 1. Grooming strategy: road guidance; 2. Sponge strategy A: public land and open space for construction provide flood detention volume, absorb road excess Flooding; 3. Sponge Strategy B: (more) the new base provides “storage flood storage volume”, upper and middle travel “suppressed outflow” and downstream “accumulate road over flooding”; and 4. defense strategy: building construction The water sluice gate, the government "develops the urban flooding potential real-time forecasting system", informs the people in the flooded area 30 minutes in advance, and deploys the sluice gate. In this study, EPA-SWMM was used as a simulation tool. The Daan District of Taipei City was used as an example to evaluate the benefits of the first three strategic combinations. The defensive strategy can assist the people to install the sluice gate according to the flooding depth of the case simulation.
Take Daan District, Taipei City, which is prone to local flooding, as an example. Using design rainfall and actual event rainfall, simulate the combination of road guidance, open space flood detention, and prevention of flooding intrusion strategies for flooding depth reduction and impact reduction. Among them, the road guide design can reduce the maximum flooding depth by about 60%, and then add the open space descent and 10% area of 78mm "storage and detention facilities", which can reduce the maximum flooding depth by about 70%. The simulation case found that if there is no road guide, the flooding cannot be diffused and it is easy to accumulate locally, and the flooding depth is too large; if there is no flood detention volume, the flooding cannot be reduced, but the downstream is transferred, but it will intensify the downstream flooding; After using the road guide and the flood detention volume strategy in Da'an District, the internal flooding caused by short-time heavy rainfall will not invade the underground space and buildings. Finally, before implementing road guidance, storage and detention facilities, and public space flood detention strategy, it is recommended to develop flooding potential forecast in the future, notify individuals, communities, etc. about 30 minutes in advance, and install a damper, a tropical island-type climate in Taiwan. Can truly become a resilient city that is not afraid of flooding.

並列關鍵字

Roadway Drainage ； Peak Rainfall ； Surcharge Water Retention ； SWMM ； Management Inundation Strategies

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