統計手法による河道内植生消長シミュレーションモデルの構築

抄録

As a practical tool for planning and implementation of forestation measures in maintenance management of rivers, a simulation model with vegetation growth and disappearance in river channels by statistical methods was constructed for Saba River. First, we defined the vegetation transition rank that integrates the plant communities and the vegetation transition type that represents the pattern of change in vegetation transition rank. Then, the decision tree analysis was performed as the model with vegetation growth and disappearance. In this analysis, we set the vegetation transition type and the vegetation transition rank as objective variables and height difference, distance from water's edge, dimensionless tractive force and distance from the upstream weir as explanatory variables. This model revealed that the contribution of distance from the upstream weir is large, reflecting well the features of Saba River with a lot of weirs. Effect of distance from the upstream weir was discussed and analyzed by random forest.