RELATIONSHIP BETWEEN BED VARIATION, BED MATERIAL DISTRIBUTION AND VEGETATION GROWTH IN THE KUROBE RIVER

The Kurobe river which is very steep river on alluvial fan yields a mass of sediments from drainage basin. Depositing sediments in dam reservoirs deteriorate a function of water storage. Therefore, the cooperating sediment flushing of Unazuki dam and Dashidaira dam is made in the latter period of floods to maintain the capacity of dam reservior water storage from 2001. After stopping gravel dredging in the downstream of Kurobe river, vegetation growth on sand bank has gradually begun. And then dense vegetation growth cause bed scouring of channel thalweg in downstream reach. The purpose of this study is to deepen the understanding of river channel change by investigating relationship between flood flows, gravel dredging, bed variations and vegetation growth over time in the Kurobe river and to conducts a proper river management.