Abstract
A flood occurred in Saba River which passes through Hofu City, Yamaguchi due to heavy rainfall on 21st July, 2009. The rain induced slope failure and caused a large quantity of sediment to flow into the river. In this study, the estimation of the flow balance and the sediment balance were conducted by using numerical simulation and the river bed elevation data observed before and after the flood.The numerical simulation for the flow balance in which the inflow discharge from the branch rivers and the overflow from a bank are considered is in good agreement with the observed hydrograph at the Shinbashi station. Although the numerical simulation overestimates the volume of the sediment accumulated in the river, the accumulation properties in the river can be simulated qualitatively.
