| In August 2016, heavy rainfall due to Typhoon No.10 caused violent flood damages along the Omoto river. The Omoto river flows through a valley plain, which is composed of a meandering stream channel with sand bars. This study aims to investigate the characteristics of flood flow for obtaining the data on effective river management in mountainous areas based on the results of 2-D numerical model simulations with various sediment supply conditions. The flood flows are compared with various sediment supply conditions in the Otomo-area and Akashika-areas, where severe damages are observed. According to the results of numerical simulations, it is revealed that the water level over the sand bars is obviously affected by the sediment supplies from upstream. Therefore, it is implied that the river planning in the valley plains such as the Omoto river should be based on appropriate estimation of sediment supply from the mountains. |
