PROPOSAL OF RISK MAP OF LAND AREA BASED ON RISK ASSESSMENT OF LEVEES

Abstract

 The purpose of this study is to propose a risk map for each inundation point (risk at the site), taking into account the risk assessment of levees, in order to support local residents to recognize the risk of their own 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 runoff magnitude of each river in each probability year. The results of the analysis show that the risk of inundation of the Kamizugawa 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 necessity of horizontal evacuation in the Joganji River was due to the location of the assumed bank erosion points.