Line-shaped rainbands (LRBs) have recently been identified as a significant factor in flood events in Japan. In our research, we analysed of LRBs in Japan using long-term radar rain gauge data. We aimed to elucidate the relationship between rainfall intensity, its geometrical form, duration, and cumulative quantity.

To accurately assess flood risk, it is necessary to evaluate whether a dike will fail. The internal structure and slope conditions of dikes are different from place to place, and it is difficult to survey all of them. Thus, we proposed a method to define the heterogeneity of levees as uncertainty and to calculate the dike failure as probability. Our method can set conditions of dike failure that are closer to reality, and will contribute to improving the accuracy of flood risk assessment.