砂礫州切り下げ後の長期植生動態解析に基づく樹林化抑制効果の確率論的検討

抄録

As one of the countermeasures for the forestation on gravel bars, excavation of gravel bars is recently conducted. To conduct effective excavation for preventing re-forestation during long term, stochastic analysis is needed considering various flow discharge condition. Therefore, objective of this study is to clarify the effect of forestation due to the excavation of the gravel bar. To fulfill the objective, the long term growth dynamic model was used for evaluating the possibility of forestation under various discharge condition. The developed model was applied to gravel bar at Honda in Arakawa River. Expected value of forestation (EV) was defined and its value was calculated in each excavation type. As a comparison of EV in each excavation type, EV value for Case 6 which gravel bar is excavated diagonally, becomes smallest. It is indicated that developed model can evaluate the suitable excavation type for preventing re-forestation on the gravel bar.