洪水氾濫時の防災樹林帯の効果に関する検討

余笹川流域を対象として

抄録

For the purpose of minimizing flood damage, measures by river structures are effective and must be strongly promoted. However, preparation for the unexpected flood inundation is also indispensable from the viewpoint of risk management. In this report, as an alternative for ordinary flood control measures, flood damage mitigation by means of groves in the floodplain is proposed. Groves cause drag to the flooding flow and decrease hydraulic force to houses behind them, thus mitigate damage to houses.
To evaluate the effect of groves in the flooding flow, and clarify the durability of trees against being swept away, a study was done for the big flood inundation in the Yosasa river basin in 1998. Field survey, comparison of aerial photos before and after the flood and flood simulation proved the damage mitigation effect of groves and showed the relation between hydraulic parameters and durability of trees.