環境維持流量評価のためのダム下流部の伏流過程に関する考察

抄録

Recently, the preservation discharge for conservation of river environment has been drained off from a reservoir in order to improve the flow condition of river in downstream of the dam. However, in the watershed basin which sedimentary materials are actively produced from a mountainous area, it is impossible to disregard the seepage flow from river channel, i.e. the river-bed flow, because a thick layer of sediment has been formed on the bottom of valley. The purpose of this research is to consider the hydraulic characteristics of the river-bed flow in downstream of dam. Through theoretical analysis based on the physical principles, the spatial distribution of seepage potential and the seepage rate and its total quantity from the channel have been evaluated. The analytical results has been compared with the laboratory experiments and the qualitative properties of phenomena have been clarified.