跨集水區淹水模擬之影響與探討

Modeling the Impact of Cross-Catchments on Inundation

張向寬(Hsiang-Kuan Chang) ； 林永峻(Yong-Jun Lin) ； 賴進松(Jihn-Sung Lai) ； 譚義績(Yih-Chi Tan)

《農業工程學報》 62卷3期 (2016/09) Pp. 74-88

https://doi.org/10.29974/JTAE.201609_62(3).0007

摘要

臺灣地區常受颱風、豪雨侵襲而造成淹水災害，致使人民生命及財產蒙受損失，為了對於此類災害預防及應變有所參考，經常使用數值模式進行淹水潛勢模擬。受限於模式之計算能力與時間或硬體設備不足，一般常以區域排水之集水區為一單元進行模擬分析。然而在高重現期暴雨與洪水條件下，邊界地區之地表漫地流將會跨集水區流動，如僅考慮單一集水區，易造成邊界地區之淹水水位產生較大的誤差。本研究以典寶溪排水系統與後勁溪排水系統為例，使用SOBEK 水理模式進行淹水模擬，選擇凡那比颱風與莫拉克颱風兩個事件，作為模式參數之檢定與驗證。之後，再進行重現期10 年、25 年、50 年、100 年情境的模擬，並分別進行各別單一集水區淹水模擬與跨集水區淹水模擬，以探討相鄰兩集水區之邊界區域其淹水面積、平均淹水深度、淹水點淹水深度之差異與影響，以作為未來建置淹水模式模擬區域之重要參考。

關鍵字

地表漫地流 ； SOBEK 水理模式 ； 跨集水區

並列摘要

In Taiwan, floods are usually induced by heavy rain triggered by typhoons or torrential rain, and they claimed residents' lives or huge property losses. The flood simulations are used by different levels of governments to assist on flood disaster mitigation and prevention. The flood simulations are often performed based on one single catchment delineated by the drainage system due to the limited computing power of model, limited time, or insufficient computation resources. However, the overland flows sometimes run across the boundaries of two nearby catchments under torrential rain of large return periods. If two single adjoinedcatchments are adopted for flood simulations (i.e. simulating the two catchments separately), the error of flood depth of flood simulation along the boundaries of two catchments may increase. To investigate the impacts of using two single catchments or one combined catchments (cross-catchments) as computation domain, Dian-Bao-Chi drainage system and Hou-Chin-Hsi drainage system are chosen for the study area. SOBEK flood simulation model are adopted for flood simulation in this study. The scenarios of Typhoon Fanapi and Typhoon Morakot are used for model calibration and verification. The flood simulation scenarios with rainfall of return period of 10-year, 25-year, 50-year, and 100-year are simulated respectively for comparing the impacts of two single catchments and one combined catchments. The results of inundation area and average inundation depth over the computation domain, inundation depth of selected locations are compared for the two cases, and it can provide useful references for correctly choosing computation domains for flood simulation.

並列關鍵字

Overland flows ； SOBEK flood simulation model ； Cross-catchments