土砂の流下波形（Sediment wave）を考慮した置土による河床改善効果評価モデルの提案

抄録

Sediment replenishment below dams is a common practice in Japan to compensate sediment deficits in downstream reaches. Although the effect depends not only on sediment volume but also on distance from the sediment replenishment point, it has never been distinguished clearly in the previous studies. We propose a method to evaluate both effects of the volume and the distance by using a sediment wave model. The model consisted of dispersing wave and translating wave values was used to calculate changes in the riverbed height and size distribution of riverbed materials in the downstream reaches of the Futase Dam. Results showed that changes in the riverbed elevation by sediment wave were milder at long range than at short range from the sediment replenishment site probably because of reduction in the dispersing wave with distance. Distinguishing the effect of the distance from that of the volume, this model would be of use for evaluation of riverbed improvement by sediment replenishment.