都市雨水貯集滯洪設施容量差別應用效益分析

A Simulation Study on Utility Design of Urban Rainfall Retention and Their Effectiveness

黃悅瑩(Yue-Ying 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(2015年)

https://doi.org/10.6342/NTU.2015.01693

摘要

本論文利用臺中市劉厝排水資料，模擬分析「建築物雨水貯留利用設計技術規範修正規定」，「建築技術規則建築設計施工篇」，「臺北市基地開發排入雨水下水道逕流量標準」，「低衝擊開發設計手冊」等規範與洪澇管理手段，並檢討設施不同應用策略和設計容量，在減少逕流量和淹水的效益。
根據觀測降雨歷線或設計雨型，以美國水土保持局（SCS, Soil Conservation Service）的曲線數法計算降雨損失，應用區塊運動波直逕流模式（BKW, Block Kinematic Wave）計算逕流歷線，將其輸入並結合SWMM（Storm Water Management Model）的幹線輸水模組（EXTRAN Module），建立下水道和市街流兩個圖層，沿道路設置人孔，並在人孔處設置雙向銳緣堰，作為雙層排水系統根據水面高程交換流量的控制機制。設計降雨採用Horner公式的降雨強度－延時－頻率函數，選擇重限期、計算各延時的降雨強度，並以水文設計應用手冊中的SSGM法設計雨型，建立評估檢討設施效益的設計降雨。
採用降低SCS法曲線數的方式，模擬低衝擊開發設施；雨水貯集滯洪設施則是使用溢流堰控制流量，若區塊逕流量超過設定流量，或市街渠流水深超過容許高度，便通過測流堰，進入雨水貯集滯洪設施。模擬分析顯示，若為短延時、低重現期降雨事件，設置低衝擊開發設施的逕流減量效益高於雨水貯集滯洪設施，低衝擊開發可以同時削減總逕流量和洪峰流量；若為長延時降雨事件，設置雨水貯集滯洪設施的效益較佳。
若採用空間均勻分布策略設置雨水貯集滯洪設施，則上游因逕流量不大，淹水深度沒有達到於流入標準，多未使用。以中游減（逕流）量概念設置的雨水貯集滯洪設施，多數容積也未使用，使用的容積多在局部低漥或出流口附近；且模擬結果顯示，淹水是先進入局部較低漥處雨水貯集滯洪設施，當此設施滿載後才會進入附近另一個雨水貯集滯洪設施。顯示若有可能，雨水貯集滯洪設應該優先設置在低窪的易積淹水路段。分析模擬結果，建議都市內水防澇減災管理策略，可略作為上游減量、中游滯澇、下游防澇。

關鍵字

逕流減量設施 ； 雨水貯集滯洪設施 ； 低衝擊開發 ； SWMM ； 區塊運動波直接逕流模式

並列摘要

This thesis simulates and analyses the regulations and strategies about flood management, including “Regulation Amendment for Building Rainwater Harvesting, Reuse, and Detention, Design and Technical Specifications”, “Building Technology Rules, Design and Construction articles”,”Taipei Construction Site Rainwater Drainage Standard”,“Low Impact Development Design Handbook”, with drainage system data of Liu Cuo in Nantun Dist., Taichung Country. Therefore, we examine their effectiveness in reducing runoff and peak flow.
The effective rainfall time series are processed by the curve number method of SCS. And thesis time series are the input of BKW model which can calculate and output runoff time series. Then combining with EXTRAN module in SWMM, we construct two layer drainage system, sewer system and street system, as well as importing the dates from BKW model. Two layers in SWMM are connected by weirs, which can simulate the phenomenon that the flow in sewer system overflow to streets or flow in the street system backflow to sewers. Then thesis evaluates the strategy and facilities with BKW+SWMM model and design hyetographs, which are built from Horner’s equation and SSGM with local variables.
About simulating facilities, decreasing the curve number performs the change after applying Low Impact Development and establishing the storages and weir in SWMM present the region installing rainfall retention space(雨水貯集滯洪容積= rainwater storage and retention volume).
From the simulation results, Low impact development is effective when the total rainfall volume are relative small. However, rainfall retention space can effect reduce the peak flow which the drainage system can’t bear. Additionally, there is a phenomena that if we set rainfall retention space and let them distribute evenly in space, there are specific ones be used which are located in lower elevation area or closed to the ends of sewer.
According to the analysis of simulation results, this thesis proposes the flood management in urban area can be “reducing volume in upstream, retaining flood in midstream and preventing flood in downstream”.

並列關鍵字

SWMM ； BKW ； LID ； Rainfall Retention Space

參考文獻

史健軍, & 高家偉. (2007). 蘭陽地區住宅小型雨水回收系統雨水貯留槽容積探討. [A Study on Household Rainwater Tank Volume for Lan Yang Area]. 蘭陽學報(6), 8-17.

張富銘. (2015). 低衝擊開發規劃與設計之研究(Low Impact Development of research and design). (博士), 國立臺灣大學.

Botzen, W. J. W., Aerts, J. C. J. H., & van den Bergh, J. C. J. M. (2013). Individual preferences for reducing flood risk to near zero through elevation. Mitigation and Adaptation Strategies for Global Change, 18(2), 229-244. doi: 10.1007/s11027-012-9359-5

Chen, T.-C., Wang, S.-Y., & Yen, M.-C. (2007). Enhancement of afternoon thunderstorm activity by urbanization in a valley: Taipei. Journal of Applied Meteorology and Climatology, 46(9), 1324-1340.

Chow, V. T. (1964). Handbook of applied hydrology.