Abstract
A numerical simulation model was developed to describe the habitat of benthic macroinvertebrates, which includes two types of riverbed structure simulation and two types of habitat evaluation for the benthos in gravel-bed. The model was applied to an actual river around a dam for model verification, in which the composition rates of bed material and the community structures of the benthos were compared with field data. The result of the numerical simulation shows that the non-equilibrium simulation for riverbed structure can reproduce the spatial change of the composition rates of bed material at observation sites. Comparing between the results of the numerical simulation and the field data, the composition rate of Bed-residence types at the downstream of the tributary confluence has shown a tendency of rehabilitation toward the composition at the upstream by supply of fine sediment from the tributary.
