A GIS-ASSISTED DISTRIBUTED WATERSHED MODEL FOR SIMULATING FLOODING AND INUNDATION1

Authors

  • Tsang-Jung Chang,

    1. Respectively, Assistant Professor and Professor, Department of Agricultural Engineering, National Taiwan University, Taipei, 106, Taiwan, R.O.C.; and Research Associate and Research Assistant, Flood-Mitigation Research Group, National S&T Program for Hazards Mitigation, National Taiwan University, Taipei, 106, Taiwan, R.O.C. (E-Mail:Chang: tjchang@ccms.ntu.edu.tw).
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  • Ming-Hsi Hsu,

    1. Respectively, Assistant Professor and Professor, Department of Agricultural Engineering, National Taiwan University, Taipei, 106, Taiwan, R.O.C.; and Research Associate and Research Assistant, Flood-Mitigation Research Group, National S&T Program for Hazards Mitigation, National Taiwan University, Taipei, 106, Taiwan, R.O.C. (E-Mail:Chang: tjchang@ccms.ntu.edu.tw).
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  • Wei-Hsien Teng,

    1. Respectively, Assistant Professor and Professor, Department of Agricultural Engineering, National Taiwan University, Taipei, 106, Taiwan, R.O.C.; and Research Associate and Research Assistant, Flood-Mitigation Research Group, National S&T Program for Hazards Mitigation, National Taiwan University, Taipei, 106, Taiwan, R.O.C. (E-Mail:Chang: tjchang@ccms.ntu.edu.tw).
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  • Chen-Jia Huang

    1. Respectively, Assistant Professor and Professor, Department of Agricultural Engineering, National Taiwan University, Taipei, 106, Taiwan, R.O.C.; and Research Associate and Research Assistant, Flood-Mitigation Research Group, National S&T Program for Hazards Mitigation, National Taiwan University, Taipei, 106, Taiwan, R.O.C. (E-Mail:Chang: tjchang@ccms.ntu.edu.tw).
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  • 1

    Paper No. 99053 of the Journal of the American Water Resources Association.Discussions are open until June 1, 2001.

Abstract

ABSTRACT: A distributed watershed model combining kinematic wave routing, 1-D dynamic channel-flow routing, and 2-D diffusive overland-flow routing has been developed to simulate flooding and inundation levels of large watersheds. The study watershed was linked to a GIS database and was divided into an upstream mountainous area and a downstream alluvial plain. A kinematic wave routing was adopted at the mountainous area to compute the discharge flowing into the alluvial plain. A 1-D dynamic channel routing solving the St. Venant equations by the Preissmann method was performed for the main channel of the alluvial plain, whereas a 2-D overland-flow routing solving the diffusion wave equation with the Alternating Direction Explicit scheme was used for floodplains. The above two routings were connected by weir-link discharge formula. The parameters in the model were calibrated and independently verified by single-event storms. An example application of flooding/inundation analysis was conducted for the Taichung station and the Woozi depot (Taiwan High Speed Rail). Suggested inundation-proofing measures - including raising ground surface elevation of the station and depot and building a waterproofing exterior wall and their combination - were investigated. It was concluded that building the waterproofing exterior wall had a strong tendency to decrease peak inundation depth.

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