The Coupling of Inland And River Inundation Flood Analysis in Jikjisacheon

Kun Yeun Han, Ah Long Son and Young Joo Kim

ABSTRACT

Recently, the flood damage has been increasing because of the intensive rainfall caused by abnormal climate phenomena such as global warming. Korea had to cope with several major typhoons and extreme rainfall in 2002. The total losses amounted to about 5 billion 148 million won and casualties were 246 people in Korea during Typhoon Rusa. Therefore, it is necessary to establish the structural and nonstructural flood control system to prevent and mitigate the flood damage.

The purpose of the study is to establish of flood analysis method from inland and river inundation analysis including underground spaces in Jikjisacheon basin. In this study, HEC-HMS model was used for the hydrologic analysis, FLDWAV model was used for the hydraulic analysis, EPA-SWMM model was used for the drainage analysis and finite difference scheme was used for inundation analysis.

EPA-SWMM model which is applicable to inland inundation has been used for this study to calculate overflow discharge at manholes. Shinum drainage district has been chosen as study area. Variation of water stages at the 3 outlets were computed by simulation of one dimensional river routing for Typhoon Rusa event. This water stage data were inputted as boundary condition of inland inundation model constructed for pipe network analysis.

Overflow discharge manholes and levee results of inland and river inundation analysis simulation using FLDWAV and SWMM model are presented.

For verification and calibration of the model parameters, this study evaluated the flood discharge and flood stages in Gamcheon river and Jikjisacheon and simulated data was compared with observed data in terms of flood area and depth including underground spaces during the Typhoon Rusa on August 31, 2002.

So, the result of this study will be utilized for the construction of integrated flood inundation analysis system of practical affairs. And this study extends to make disaster education program for the residents and also can greatly contribute to the construction of a high accuracy flood system that can secure forecast lead time for flood disaster prevention and mitigation.


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