博士 / 國立臺灣大學 / 生物環境系統工程學系暨研究所 / 90 / The rainfall-runoff process in urban areas is primarily affected by the anthropogenic factors such as drainage facilities, local alternation of topography and land use. The surface runoff in urban area is usually collected by the inlets and drains to the sewer systems. When the runoff discharge exceeds the drainage capacity, the sewer systems are not always able to carry all the runoff due to the limited capacities of inlets or conduits. As a result, inundation takes place. The excess water, including the rainfall excess and overflow from surcharged manholes, becomes overland runoff flowing on the surface toward lowlands until it reached other under-capacity drainage inlets.
A dynamic model is developed for the simulation of the complex hydraulic process in urban areas, and the investigation of the interaction between overland and storm sewer flows. A two-dimensional overland flow model is employed for the calculation of surface flooding. Meanwhile, the Storm Water Management Model developed by U.S. Environmental Protection Agency is modified herein and applied for flow routing in storm sewers. The drainage through inlets to the sewer systems and the overflow from the surcharged manholes to ground surface are used for model linkages between the overland flow model and sewer routing model. The former is treated as the sink and the latter as the source in the two-dimensional model. Furthermore, the storage effects of underground infrastructure during flooding, the operation of detention ponds and pumping stations, and the over-banking flow from rivers are taken into consideration in this study.
Both the two-dimensional overland flow model and storm sewer model are solved with explicit schemes, which require long computating time for problems with a large amount of computation grids. Hence, the technique of parallel processing is introduced for shortening the computing time and improving the efficiency of model.
An idea axis-symmetric circular plane with a horizontal surface is used for model verification. The comparison of the simulation results, computed by the present two-dimensional model and a one-dimensional numerical model with relative-high grid resolution, demonstrated that two-dimensional model has good accuracy. The model is also compared with another previous developed model applied in the Muchia area of Taipei City during the Typhoon Xangsane. The results indicate that the newly developed model reflects more realistic physical processes than the previous model. The model is applied for the Typhoon Nari event in Downtown Taipei. The simulation inundation extent is close to the field survey. Besides, the inundations of the 50-year and 100-year rainfall in Tainan Science-Base Industrial Park are investigated as well. It is reveal that the model is suitable for the flood simulation of an urban area under high intensity of rainfall.
| Identifer | oai:union.ndltd.org:TW/090NTU00404005 |
| Date | January 2002 |
| Creators | Shiuan-Hung Chen, 陳宣宏 |
| Contributors | Ming-Hsi Hsu, 許銘熙 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 188 |
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