Author(s): Tomoko Kyuka; Satomi Yamaguchi; Kento Watanabe; Yasuyuki Shimizu
Keywords: No Keywords
Abstract: In recent years, invading vegetation such as willows on mid-channel bars and floodplain are one of the major problems in river management, especially Hokkaido island, however, the knowledge about the initial invading processes, whose seeds are mainly distributed by snow-melting season, have not been understood well yet. The objectives of this research are to confirm the characteristics of floodplain vegetation distribution on braided channel and its effects on channel morphodynamics by means of laboratory experiments. The results showed that high density vegetation on sandbars led channel decreasing and meandering as well as previous researches. In contact, when seeds were distributed by flow from the inlet section of the flume, seeds were settled in wide areas on sandbars and then formed longitudinal vegetation-patches in line on sandbars. These vegetation patches made channel formation complicate because of the increasing in the number of small scale channels. This mechanism could be one of the mechanism to be maintained multi-thread channels with vegetation effects.