Author(s): Ryusei Yagi; Shuichi Kure; Shouma Ishikawa; Bambang Adhi Priyambodho
Linked Author(s):
Keywords: Flood inundation simulation; Risk rank evaluation method; Hazard maps; Jinzu river; Jouganji river
Abstract: The purpose of this study is to propose a countermeasure to promote early evacuation in areas where residents typically underestimate flood risks and experience fewer disasters. As one of the countermeasures, we examined whether it is possible to improve the presentation of hazard maps and to promote evacuations. This study proposes a new risk rank evaluation method using flood inundation simulation results. Two rivers, the Jinzu and the Jouganji River, were chosen, and Toyama City, which was inundated by the target rivers, was selected as the target area. A flood inundation model was applied to the target area to compute the flood inundation depth and velocity. Flood inundation simulations with several scenarios were analyzed in the computation. We simulated the worst-case flood inundation to demonstrate its effects to the local people. In addition, a new risk rank evaluation of the flood inundation that identified safe and unsafe areas was proposed to formulate a new flood hazard map in this study. Based on the results of the flood simulations, hazard maps consisting of only two colors (safe and unsafe zones) were created based on the new risk rank proposed in this study. We believe that the hazard maps that uses only two colors can have a strong impact on the residents, who underestimate the risks, and can promote evacuation in the event of a flood disaster.
Year: 2020