抄録
This paper describes the topographical changes of sand-bar and the destruction of herbaceous vegetation on the sand-bar in the Kita River. The sand-bar in the Kawasaka district was excavated with vegetation in 2001 through the special emergency project after the sever disaster due to flooding by Typhoon No.19 in 1997. A flood on Oct. 2004 destroyed again almost all vegetation in a recovery process on the sand-bar. Nowadays, herbaceous vegetation is restored over all the sand-bar because of no flooding since 2008.In the paper, the destruction of herbaceous vegetation by the topographical changes of sand-bar was simulated through the 2-D analysis of the riverbed evolution. It was considered from the simulation that almost all vegetation will be destroyed by the flood over the maximum discharge of 4,000m3/s. Moreover, it was found that vegetation will not be destroyed but grow thick by the flood under the maximum discharge of 2,000m3/s.
