河床構造に着目した山地河川のサブセグメント区分と河床材料粒径の規定要因

抄録

The number of the engineering studies on mountainous rivers is limited, though it’s quite important when we examine the sediment transportation in the whole basin scale. In this study, we focused on the relationship between the bed material size and various hydraulic parameters, and proposed the sub-segment classification of the mountainous stream.

Through the field measurements at 44 points in Kanto region, we found out riverbed slope 1/40 is clear boundary of that whether step-pool structure develops or point bars develop.

On the riverbed where the thickness of the active layer is very thin, the bed material and tractive force during flood has close relationship which was reported in previous studies. The riverbed with thick layer, however, bed configuration such as step-pool structure develops and its characteristics agrees with the theoretical features.