Abstract
This study aims to determine the sediment volume generated by slope collapses in a river basin based on hydrological and geographical factors. For comprehensive sediment management throughout the river basin, there is the need to estimate the volume of sediment yield from mountain slopes as well as to estimate river channel sediment dynamics. In estimating the volume, one must consider not only the scale of rainfall during flood, but also the basin storage capacity, which is an index of the degree of moisture in the basin. Therefore, the authors quantified the basin storage capacity by using a hydrologic cycle model that simulates long-term spatial distribution of rainfall and runoff before and during a flood. This paper proposes equations for estimating the volume of sediment yield in the Nukabira river basin of Hokkaido by using rainfall, slope angle and basin storage capacity as explanatory factors. As a result, good reproducibility was obtained for the total of sediment volume and for the distribution of sediment.
