流域地質特性に着目したダム下流の底質形成過程の解明

抄録

There is a phenomenon called armoring of the river bed as an impact of dams to its downstream, and has been researched previously by several researchers. However, previous researches often focused on one particular dam, therefore comparison of the phenomenon among several rivers which have different characteristics has yet to be conducted. In this research, we focused on several dams in rivers which have different geological features in its basin. As surveys, we took data of bed materials upstream and downstream of dams, and compared them. Based on these data, we found that the armoring of the river bed seldom occurs when the geology of the river basin is sedimentary rocks, and it frequently occurs when the geology is volcanic rocks. More in detail, the location of the landslide affects the size distribution of the river bed. The size will be smaller when the landslide exists in downstream of dams, and larger when it does not exist.