Author(s): Hirotaka Moriya, Yasuo Nihei, Rikito Mizuno, Tomoya Kataoka
Linked Author(s): Yasuo Nihei
Keywords: Flood disaster, Omoto River, flood simulation, field survey, heavy rain
Abstract: Typhoon No. 10 has brought heavy rain to Northern Japan especially to the Tohoku and Hokkaido regions, and caused heavy flooding. The rain recorded is 66mm per hour in Iwaizumi city, Iwate prefecture. Due to the heavy rain, 21 people are dead or missing in Iwaizumi city. Nine of the dead are in a nursing home located in the Otomo district, Iwaizumi city, and near the Omoto River. In this study, field survey and numerical analysis are conducted to understand the flood inundation mechanism in the Otomo district, Iwate prefecture. The numerical simulation is done with runoff analysis and 2D horizontal flood simulation. From this data, we aim to investigate the inundation process in the initial flooding, which is important for early evacuation. The results show there are two stages of flooding that are mainly caused by mountainous area and the upstream of the Omoto River. The initial flow velocity is about 1. 0m/s. Therefore, it is difficult for the elderly to evacuate in this situation. From the above results, it is confirmed that early evacuation is necessary in this kind of situation
Year: 2017