都市地區淹水改善措施之效益評估研究---子計畫：都市地區淹水模式之評估與應用研究(I)

Abstract

隨著台灣社會經濟發展，都市地區颱洪暴雨所帶來之淹水課題也日受重視，如排水 閘門之管理操作、滯洪池之設置、分洪道之規劃、都市計畫發展與地下水道設計結合等。 由於颱風、豪雨等天然災害之存在，使得都市排水與抽水站管理倍受矚目，如2001 年 納莉颱風重創北部地區淹水，造成地下鐵與捷運系統癱瘓；2004 年敏督利颱風重創全台 多個鄉鎮；2005 年海棠颱洪對台北及宜蘭縣農作物受損嚴重，部份低窪地區因積水不及 宣洩造成良田農舍泡水有如汪洋。因此，都市排水、淹水課題對人民安全及財產之影響 攸關重大。淹水地點與範圍受排水設施功能之限制，而排水設施承受之水量來自降雨形 成之地表逕流，經由街道及其邊溝與邊溝進水口流入雨水下水道，傳輸至水門或抽水站 而洩排入臨近之區域排水、河流、或湖泊海域。因此都市地區之淹水現象須整合淹水模 式(降雨-逕流演算)、街道路網水流模式、雨水下水道網路模式、水門及抽水站操作模式 等進行模擬演算。 本計畫研究目的在於對多個都市淹水模式理論與數模進行回顧，並評估既有國內外 常用先進淹水模式之優缺點與功能限制，進而擇之應用於台灣本土案例。同時，依據總 計畫之執行目標，結合各子計畫如降雨分佈、防洪排水設施、都市下水道等相關研究， 進行共同應用對象(台北市玉成抽水站)之都市淹水潛勢分析，提出相關措施與建議，以 達到改善都市地區淹水之目的。本計畫分三年進行，第一年度以模式回顧為主要方向， 回顧與評估既有先進淹水模式之理論與計算概念，並對其模擬所需邊界條件、模式參數 敏感度分析等進行研究；第二年度以案例分析為主要方向，針對總計畫共同應用對象進 行模式實例應用，並比較評估各淹水模式實際應用之成果；第三年度以效益評估及研提 改善措施為主要方向，藉由共同應用對象之淹水潛勢分析等結果，提出可能之改善措施 與建議。

The study of flood resulted from typhoons and storms at urbanized area is taken seriously accompanied by the rapid growth of socioeconomic development in Taiwan. Some of the examples include: the management and operation of storm water gates, the installation of detention pound, the planning of flood diversion way, and the combination of urban planning development and storm sewer design. The management of urban storm water and the pump stations is therefore brought to great attention, for example: the paralyzed MRT system in Taipei by the flood resulted from the Nari Typhoon in 2001; the heavy damages on the cities and towns by the Mindulle Typhoon in 2004, and the inadequate drainage of floods at parts of Taipei by the Haitang Typhoon in 2005. Therefore, the discharge of flood has crucial effects on the protection of the lives and properties of citizens. The locations and area of inundation are affected by the function of drainage facilities, which bears the flow from the runoffs resulted from the rainfall. This runoff flow through the streets and the inlets of the trenches leading to the storm sewer before being transported to the water gates or the pump stations in order to be drained to the rivers, lakes, or coastal areas nearby. Therefore the phenomenon of inundation could be simulated by integrating the inundation model, street network surface flow model, the storm sewer network model, and the operation model of the water gates and pump stations. The purpose of this study is to review six urban inundation model theories and numerical models to evaluate the advantages, disadvantages and limitations of the existing domestic and foreign modern inundation models in order to choose and apply to the local cases in Taiwan. In the meantime, the sub-plan researches such as the rain fall distribution, flood control and drainage facilities, and the urban sewer are combined for the analysis of the urban potential inundation trend of the applied target (the Yu Cheng Pump Station in Taipei). Related suggestions and measures would be made in order to achieve the goal of improving the inundation control in urban settings. This plan would be divided into a three-year study. The first year would be the review and evaluation of existing inundation model theories and their computations with emphasis on the research of the boundary conditions needed for the simulations plus the analysis of the sensitivity of the model variables. Entering into the second year, there would be an actual application of the model on the target of interest where the results from different models would be compared and evaluated. Counter-measures and suggestions would be made in the third year, after attaining the results from the potential inundation tendency analysis.