Author(s): M. F. Karim; John F. Kennedy
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Keywords: No Keywords
Abstract: Channel degradation in response to interruption of a river's sediment discharge is analyzed for the case of nonuniformn bed materials by formulating a relation between degradation depth and median particle size in the mixed layer that is actively participating in the transport process, and adaption of an expression for sediment discharge as a function of bed slope and particle size. Particles of di fferent sizes are assumed to be distributed homogeneously within the mixed layer with thickness equal to the average dune height. Incorporation of the resulting bed-material size relation into sediment continuity equation yields a second-order, nonlinear partial differential equation for degradation depth. This governing equation, expressing degradation depth as a function of distance and time, is first linearized and solved in closed form, and solved exactly by an iterative process applied to the camplete equat ion. Ihe results of the latter are found to be in good agreement with the observed data from the Colorado River downstream fram Hoover Dam.
Year: 1985