2006 年 12 巻 p. 323-328
Bed matereals are composed of volcanic ashes at estuary reaches of some rivers which flow into Ariake Sea(Bay). And those river channels made by volcanic ashes of silt and clay belong to delta-river category in river segment classification. Characteristics of channel formation processis different from regular delta-river. And also characteristics of individual ash river is different. ln this paper, the meandering characteristics and the stability of volcanic ash rivers which flow into Ariake Sea(Bay) were investigated. And it was clarified that the volcanic ash rivers were mainly formed by the deposition of sediment from the sea area, and the meandering patterns were mainly controlled by tidal prism, the rate of discharge from the upstream and effects of sediment characteristics of each river.