PROPOSAL OF VERTICAL/HORIZONTAL EVACUATION ZONE CLASSIFICATION BASED ON FLOOD INUNDATION ANALYSIS AND RISK RANK EVALUATION FOR THE JOGANJI RIVER AND JINZU RIVER

Abstract

 The purpose of this study is to improve the presentation of hazard maps and promote evacuations in areas where residents typically underestimate flood risks. 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 was selected as the target area. 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.