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Linear system theory for storm runoff simulation in urban area
|Authors: ||Chung-I Lin|
|Contributors: ||NTOU:Department of Harbor and River Engineering|
unit hydrograph;sewer flow routing;storm sewer;urban flood guidance
|Issue Date: ||2011-11-23T03:18:26Z
|Abstract: ||由於台灣降雨多集中於颱風期間或夏天暴雨之際，因而導致逕流之洪峰流量快速的產生；且氣候變遷與平原地區之都市化，造成都市區域更易於遭受嚴重的淹水災害，產生巨額損失。淹水預警系統乃是考慮都市雨水下水道於暴雨期間之排水能力，提供有效之資訊，而減少災害於都市區域所造成之財物損失。有鑑於都市水文記錄資料難以取得，無法藉由紀錄資料以傳統線性水文方式求得單位歷線，故本研究首先採用XP-SWMM軟體進行都市集水區之降雨-逕流模擬，以推估時變性下水道單位歷線(sewer unit hydrograph, SUH)，進而針對暴雨期間之逕流模擬預測，發展演算快速且數值穩定之降雨-逕流演算模式。 SUH模式乃是本研究同時考慮都市空間降雨分布及下水道系統逕流特性，所發展之非線性與時變性水文演算模式。研究中預先應用不同尺度面積之假想都市雨水下水道系統進行SUH模式之檢測；而後採用數場颱風暴雨事件降雨資料，針對羅東都市雨水下水道系統進行模式模擬分析及驗證；結果顯示，SUH模式所產生之逕流結果與XP-SWMM軟體模擬所得之逕流結果相近，且兩模式之歷線尖峰相對誤差均少於15 %，以及尖峰到達時刻幾乎相同；因而可知，SUH模式於都市雨水下水道模擬有不錯之適用性。本研究同時結合迅洪指標(flash flood guidance, FFG)之概念與灰色降雨預測模式，幫助羅東都市區域建立完整之都市淹水預警系統，使民眾得以躲避可能發生之淹水災害。|
Taiwan has concentrated rainfall during typhoons and summer rainstorms, which usually result in a large amount runoff peak promptly. More recently, impacts from global climate change and local urbanization induce more serious flood disaster in cities and cause tremendous losses. In considering the limitation of urban storm sewer system during storms, a flood warning system may be able to provide useful information in advance to reduce the loss of property in urban areas. Since hydrological records are usually unavailable in urban catchments, the XP-SWMM hydraulic model was adopted firstly to simulate the rainfall-runoff relationships in urban catchments. Based on the data generated from the XP-SWMM model, a time-varying sewer unit hydrograph (SUH) was then developed for runoff prediction during rainstorm to obtain a computationally efficient and numerically stable model. The SUH developed in this study is a nonlinear and time-varying hydrological model which can consider temporal rainfall distribution and flow hydraulic characteristics in urban sewer network system. The SUH model has been applied to two different sizes of hypothetical sewer systems for a priori check, and rainfall data and street inundation record from a severe typhoon in Lotong Township of Taiwan were collected to demonstrate the capability of the proposed model for runoff simulation in urban catchments. Analysis results show that flow hydrographs simulated by using the proposed SUH model are similar with those generated from the XP-SWMM model. The relative difference of hydrograph peak discharge was lesser than 15% for most simulation cases and the difference for the time to peak discharge was almost negligible, which has proved the applicability of the SUH model for runoff simulation in urban catchments. Moreover, a flash flood guidance (FFG) concept combined with a grey rainfall prediction model were also include in this study to develop a complete urban flood warning system for Lotong Township to avoid possible disaster.
|Appears in Collections:||[河海工程學系] 博碩士論文|
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