Author(s): Takahisa Gotoh; Shoji Fukuoka
Linked Author(s):
Keywords: Sediment entrainment; Suspended load; Non-equilibrium sediment motions; Quasi-three dimensional flow and bed variation analysis; River mouth sandbar
Abstract: Large amount of the fine sediments around river mouth are transported in states of suspensions during a flood. The suspended sediment entrainments are characterized by interactions between bed load motions and suspensions of the sediments. In general, the suspended sediment entrainments which was the boundary conditions at the bottom of the advection-diffusion equation of suspended sediment concentrations were estimated by applying equilibrium conditions of sediment motions. In this study, the quasi -three dimensional flow and bed variation analysis method considering the non-equilibrium flows and sediment motions with large amount of suspended sediments was developed. And the interactions between bed load motions and suspensions was also taken into account the bed variation analysis method. The developed analysis method was applied to the 2011flood in the Aganogawa River with large-scale topographical changes in the river mouth sandbar. The calculation results elucidated the enlargements processes of opening widths in the river mouth sandbar and sediment depositions to the downstream toward sea due to the flood.
Year: 2020