In slow open channel flow that features emergent vegetation, the dispersal of floating particles is affected by hydrodynamic characteristics at the free surface (e.g., surface tension), fluid drag, and inertial impaction. We investigated the interaction mechanism between floating particles and emergent stems. A mechanical model that considers the combined effect of fluid drag and inertial impaction has been presented to predict the probability that a particle collides with emergent stems. This model correctly captures the expected positive correlation between collision probability and vegetation density for dense emergent canopies. Furthermore, a new definition of the probability that a floating particle interacts with a stem is proposed. A statistical model to predict the probability that particles are permanently captured by stems is also proposed where the physical characteristics of particles (such as density and shape) are …