平成29年7月九州北部豪雨時の赤谷川流域を対象にした表面流・地中流解析と斜面崩壊危険度評価

抄録

Numerical simulations of surface and subsurface flows and evaluation of slope failure risk in the Akatani river basin during Kyushu-hokubu heavy rain in 2017 were performed. The numerical model of surface and subsurface flow is based on two-dimensional shallow water equations and the free-surface groundwater equations with water exchanges due to infiltration processes. The new treatment of friction slope is also incorporated. The model was also verified against the observed flood marker and maximum inundation area. It showed that the proposed model can reproduce it with reasonable accuracy. The slope failure risk was estimated by slope stability analysis. The effects of infiltration and terrain change due to sediment on the flood-inundation process were also examined based on the numerical results.