Floating particle trapping and diffusion in vegetated open channel flow

In this paper we present early results of laboratory experiments to investigate the transport and diffusion of floating particles (e.g., buoyant seeds) in open channel flow with emergent vegetation. The experiments are aimed at providing a better understanding of the relevant particle-vegetation interaction mechanisms responsible for the observed diffusion processes. Qualitative observational data are then used to set up a stochastic model for floating particle transport and diffusion. Quantitative observations, such as the distribution of distances travelled by a particle before it is permanently captured by a plant and the arrival-time distributions at prescribed cross sections along the vegetated test section, are instead used to calibrate and validate the model. The comparison between theoretical predictions and experimental results is quite satisfactory and suggests that the observed relevant aspects of the particle-vegetation interaction processes are properly described in the model.