2025 Volume 81 Issue 16 Article ID: 24-16004
In recent years, due to global climate change, the annual frequency of short-term intense rainfall events has increased. In Japan, large-scale heavy rainfall disasters have occurred frequently, exposing the limitations of current river channel planning. At the same time, biodiversity conservation and environmental considerations in river management are becoming increasingly important. In this study, we investigated the effectiveness of traditional Japanese flood control techniques (lateral levee, ring levee, and two-line levee) using floodplain areas, focusing on basin flood control methods in the Katsura River basin, which suffered extensive flood damage during the 2017 heavy rainfall in northern Kyushu. Numerical simulation was used to verify the effectiveness of traditional Japanese flood control techniques using floodplains. The results confirmed that these traditional techniques help to control flood flows, prevent the spread of damage and significantly increase the time available for evacuation. Floodplain flood control is particularly effective as a flood control measure for ecologically important rivers due to the low impact of channel alteration.
