RESEARCH ON A FLOOD RISK ASSESSMENT METHOD CONSIDERING INUNDATION PROBABILITY

Abstract

 The purpose of this study is to propose a flood risk assessment method that takes into account the likelihood of flooding and to apply for the Kamanashi River flowing south in western Yamanashi Prefecture. For this purpose, each inundation category's number of inundation events was calculated for each mesh based on the data from the inundation simulation for each breach point, which is used to create a map of the expected flood inundation area. A risk assessment method was also developed using the expected value of damage to buildings caused by flooding as an indicator, and a flood damage risk assessment was conducted for the target area. Finally, using the developed risk assessment method, we analyzed the changes in flood risk over time in the flood-prone areas of the Kamanashi River.

 As a result of the analysis, it was confirmed that differences in inundation frequency in the target area can be visualized, and differences in risk due to differences in inundation frequency can be expressed by using the concept of expected value. The analysis also revealed the possibility that development may have occurred on land with high inundation frequency between 2000 and 2005 in the subject area.