There is a growing need for comprehensive reservoir sediment management in order to cope with problems such as riverbed aggradation in the reaches upstream of reservoirs and reduction in reservoir capacity, to maintain intake facilities, and to conserve the environmental conditions of rivers downstream and coastal waters. An effective means of such comprehensive reservoir sediment management is to excavate and transport part of the coarse sediment that has entered and accumulated in reservoirs to the river channels downstream so that the sediment is transported by flood water in the channels to the sea. Efforts are currently underway to develop technologies for making that method possible. In this paper, characteristics of reservoir sedimentation in Japan are explained, and the check-dam-based sedimentation control methods currently practiced in Japan are described briefly. Present practices in coarse sediment replacement, which can be expected to improve the river environment, are also described, and the future direction of coarse sediment replenishment is also discussed.
