Riverbed armoring is one of the most significant effects on stream communities caused by upstream dam constructions. Practically, there are some of the mitigation measures to be rehabilitated riverbed environment for conserving river ecosystem. Although the sediment additions below the dams have been applied as one of the effective measures, there are a few findings related to the physical-biological responses. The present study conducts field survey below and above the dam which are tried to be supplied gravel at its downstream, with particular references to benthic fish communities and their habitats. The canonical correspondence analysis for these benthic fish and habitat characteristics could show that the impacts of armoring and the mitigations due to gravel additions have altered the benthic fish fauna, respectively.
