行政院國家科學委員會補助專題研究計畫成果報告:防洪示範區淹水境況模擬與決策支援系統之研究─子計畫：基隆河流域整治段颱洪災害淹水境況模擬(I)
Date Issued
2001
Date
2001
Author(s)
DOI
892625Z002060
Abstract
Metropolitan Taipei is located in Taipei basin where is densely populated. Tansui River and its tributaries, Hsindan Creek, Tahan Creek, and Keelung River run through it. Due to the topographic characteristics in the basin, the lowlands along Tansui River and its tributaries were frequently inundated. As a result the Central government has conducted the Taipei Flood Prevention Project to reduce the flood risk since 1982. According to the project, the levees with 200-year protection level were exhaustively constructed alone the Tansui River and its tributaries to confine flood flow and prevent inundation disaster except the upstream region of Keelung River like Shiji-Wudo, Zuifan town of Taipei County, and Chidou, Nannan district of Keelung City. Fast economic development in those region increase flood risk. Serious inundation disasters occurred in Shiji-Wudo area along Keelung River in 1998. On the other hand, the area along Keelung River in the portion of Taipei City was safe during Typhoon Zeb event since it is protected by 200-year levees. Overbank flooding from Keelung River mainly influences inundation in Shij i-Wudo area. Therefore, it is necessary to investigate the relationship between channel flow in rivers and overland flow in floodplains, especially the flow stage interaction.
The project belongs to the NSC three-year integrated project entitled ¡§Inundation Scenario Simulation and Decision Support System for Flood-Damage Mitigation in Pilot Areas (I)¡¨ as its 7th subproject. The main objective of this study is to simulate the interaction between flooding and inundation of Shiji-Wudo area where is under the short-term project of channel improvement for 10-year protection level managed by Ministry of Economic Affairs. The study area, starting at Nannan bridge of Keelung City and ending at Nanhui bridge of Taipei County, is 23 kilometers long and its floodplain is 60 square kilometers. A two-dimensional flooding/inundation model associated with dynamic interaction between channel flow in rivers and overland flow in floodplains will be developed in the project. In the simulation, a two-dimensional inundation model is used to simulate overland flow in floodplains, whereas a one-dimensional river routing model is adopted for channel flow using nonlinear finite difference method. The dynamic interaction between Keelung river and its adjacent floodplains is computed based on the difference between river stage and inland water stage, and is taken into account in the model simulation by using the weir or orifice formula. The two-dimensional inundation model is based on the zero-inertia concept for computation of inundation zones and depths. The effectiveness of the short-term project is also evaluated. Typhoon Zen and Babs in 1998 and Xangsang in 2000 are used for model verification. The results of inundation scenario simulation can be used for flood mitigation measure and decision support system for government agencies.
Subjects
Inundation Scenario Simulation
Overbank Flooding
Floodplain
Inundation Zone
Publisher
臺北市：國立臺灣大學生物環境系統工程學系暨研究所
Type
report
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892625Z002060.pdf
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3.07 MB
Format
Adobe PDF
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(MD5):e9303a168b406594d68a4f9f0dd8642b