Author(s): Wenjie Li, Shengfa Yang, Pingyi Wang, Yi Xiao, Jiang Hu, Xuhui Fu
Linked Author(s): Wenjie Li
Keywords: Decreasing of sediment inflow, sedimentation, fine sediment, sediment carrying capacity, Three Gorges Reservoir
Abstract: Sedimentation in the Three Gorges Reservoir (TGR) has been studied concerning mainly the amount change due to the decrease in sediment inflow. In this study, the sediment-decrease-induced sedimentation was investigated using the sediment budget and topographical methods, and the mechanism underlying the influences were analyzed based on the field data sets. The total sedimentation reduced significantly to about half of the predicted value, while the deposition ratio increased by 15. 8 %. The sedimentation mainly consisted of fine sediments, and presented a spatial pattern of �segment siltation� rather than the expected �continuous siltation�. At wide reaches, flow velocities were slowed down significantly and flocculation occurred, hence the sediment carrying capacities decreased to below the sediment concentrations, resulting in fine sediment deposition. While at gorges, flows were still energetic and the flocs were likely to be disrupted, hence the sediment carrying capacities decreased slightly and remained bigger than sediment concentrations, resulting in no cumulative deposition. The future sedimentation equilibrium with no unified bed slope and deposition delta was expected due to the decreasing of sediment inflow, facilitating the TGR's functions significantly
Year: 2017