Abstract
A numerical simulation model based on functional feeding groups and bed-residence groups was developed to describe the dynamics of benthic macroinvertebrate biomass, which includes the transport model for suspended load to evaluate the microhabitats of benthos in gravel-bed. The model was applied to the Agi-gawa river, a tributary in Kiso-gawa river system in Gifu, Japan. The calculation condition was referred to the downstream of the Agi-gawa dam. The comparison between observed benthic macroinvertebrate data and simulation data suggests that the present model can reproduce the compositions of functional feeding groups and bed-residence groups both at the upstream and downstream of the dam fairly well. The results of the numerical simulation showed that the insufficient supply of fine sediment from the upstream leads to the increase of biomass of bed-residence groups in inter-stones and the decrease of biomass of surface and interior groups.
