ABSTRACT
In Japan, sediment runoff at zero-order basins has become a serious issue from the viewpoint of disaster prevention and mitigation. Our urgent task is establishing an effective and integrated method of assessing its risk. This study analyzes topographical characteristics of zero-order basins in the actually affected three areas. We show sediment runoff is closely related to valley development and figure out the possibility of assessing the risk at differently featured zero-order basins by categorizing them into four classes; Youth, Adolescent, Mature and Old, and only by measuring their total length.
