This study proposes a workflow to support decision making by providing materials for decision making, such as grasping the effective sediment deposition situation using from ALB measurement and objectively determining the priority of countermeas-ures mainly based on the evaluation of the sufficiency of flow capacity in small and medium rivers managed by prefectures with long management extension. This paper carries out the analysis by this method in 4 rivers of prefectural management of different river scales, and examines the effectiveness of the method, while constructing a mechanism for taking measures mainly in neces-sary places considering the degree of safety and importance in flood control by effectively utilizing limited resources of river management. In addition, this paper discusses the actual condition of flood control safety of prefectural controlled rivers, and discusses the criteria of future external force considering climate change as an application of this method.