抄録
Disaster restoration works are commonly preformed based on the technical standard from the reason that there is not sufficient time of investigation and study for emergency construction. Therefore, some rivers that have special characteristics require additional studies on the changes of channel characteristics.
In this paper, the result of study of Yosasa-river was described after the disaster restoration works. The channel was considered to have such special characteristics that the natural banks were greatly scoured laterally due to the existence of tight armor coat, during the big flood in 1998 after 60 years. But, the armor coat was found not to be developed by the field investigation, and it was concluded that the degradation was not occurred by the existence of huge amount of sediment transport that was yielded by the bank erosion due to the loose materials of the banks. Now, the channel has protected banks on both sides and the rate of sediment transport is considered to be dramatically decreased. Therefore, additional counter measures are proposed in this case.
