Influence of bed armoring and clusters on bed-load transport - Experiments and Stochastic model analysis

The complex dynamics of non-uniform bed-load transport in a series of well-controlled laboratory experiments are explored systematically and simulated by a stochastic model in this study. First, both static and mobile bed armoring experiments are conducted in laboratorial flumes to monitor the transport of mixed-size sand/gravels, where apparent bed clusters develop only in the mobile armoring experiment due to the stable feeding and the relatively longer transport period. Second, a stochastic model is applied to quantify the observed dynamics of tracer particles, including the coexistence of the sub-diffusion and non-local feature caused by self-organized clusters within the armor layer. We find the strong interaction of particle-bed may cause the scale-dependent capacity coefficient for bed-load transport along mobile armor layers.