PROPOSED RISK MAPPING OF FLOOD-PRONE AREAS BASED ON LEVEE RISK ASSESSMENT

This study aims to propose a risk map for each inundation point (local safety levels), taking into account the risk assessment of levees, in order to support local residents in recognizing the potential risks to their residential areas and to promote evacuations. In this study, flood inundation analysis was conducted for multiple scenarios of the Jinzu River and the Joganji River, which run through Toyama Prefecture, in order to calculate the risk at the site. The external forces are evaluated in multiple stages using the peak discharge of each river in the return period of each year. The results of the analysis show that the risk of inundation of the Jinzu River is particularly high. Also, it was found that there is a high probability of flooding and the need for horizontal evacuation, especially in the lower reaches of the Jinzu River and low elevation areas. It should be emphasized that the need for horizontal evacuation in the Joganji River was due to the location of the assumed levee breach points.