• Journal of Wetlands Research
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• v.16 no.1
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• pp.93-102
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• 2014

In the flood plain, river facilities such as sports facilities and ecological park are builded up since the late 2000s. The recent increase of rainfall intensity and flood frequency results in the immersions of parks and river facilities located in the flood plain. Therefore it is necessary to perform the numerical analysis for the extreme rain storm in the flood plain. In this study, to analyze the hydraulic impact by lowering and rising of the water level at flood plain, Both the FaSTMECH, which is a quasi-unsteady flow analysis model to be used for simulating the wet and dry, and the Nays2D, which is unsteady flow analysis model, are used in this study. Also, the flow velocity distribution and the inundation are compared over a period of the typhoon. As a result, the flow velocity distribution at flood plain showed very low values compared to the flow rate in the main channel. This means that the problem of sedimentation is more important than that of erosion in the flood plain.