Author(s): Mingyang Wang; Tadaharu Ishikawa; Mitsuteru Irie
Linked Author(s):
Keywords: Component; Sedimentation; Reservoir; Fine sediment; Numerical study
Abstract: The transport process of fine sediment (typical grain size: 5μm) in the Joumine Reservoir was studied by numerical simulation in order to investigate the method to discharge deposited sediment for reservoir restoration. Firstly, available data of recent 13 years were analyzed for the scales and frequencies of flood events, and six typical hydrographs were selected for numerical simulation. Secondly, a mathematical expression for the pick-up rate of fine sediment was assumed by extrapolating the experimental and field data. After the preparation, sedimentation process in the reservoir was investigated in detail. The computation results show that small and middle scale floods result in sedimentation at upstream reach. On the other hand, large scale floods generate a self-accelerating gravity current by re-suspension of bed sediment, resulting in large-scale sediment transport toward the dam body. Composition of longitudinal sedimentation profiles considering the flood frequencies showed a fairly good agreement with the existing field observation by depth sounding.
Year: 2014