2024 Volume 80 Issue 17 Article ID: 24-17042
In this study, the investigation of compound hazards of tsunami and river flow was conducted using a framework of tsunami and river-flow model for Mikawa Bay, Aichi Prefecture. In addition to the 11 tsunami cases proposed by the Cabinet Office, Government of Japan, a total of 55 tsunami-river flood scenarios were assumed five pattern river flow. The largest river flow case was set to an extreme river flood event in 2023. In the case of a small river flood case (base runoff or 25% river flow), the maximum water level deviation point was the estuary. However, the maximum water level deviation point was 2.0 km upstream from the estuary in the other cases. In addition, regarding the water level rise characteristics between rivers in response to compound hazards (difference between extreme flood and base runoff), the Otowa River was the largest (+4.8m), and the Umeda River was the smallest (+1.2m). The maximum water level deviations were larger upstream during river floods in relatively large rivers with estuary river widths of 100 m or more. On the other hand, for smaller rivers with estuary river widths of less than 100 m, the maximum water level deviation was largest at the estuary in all cases.
