Developing a functional form of particle interception in vegetated environments

There is a growing body of literature seeking to evaluate particle interception in vegetated, aquatic environments. However, it is difficult to compare results of these studies due to large variation in flow regime, particle size, vegetation canopy density, and stem configuration. This work develops a functional form of particle interception efficiency (ƞ₀) in biologically active environments as a function of stem Reynolds number (Re_s), stem height, stem diameter, frontal vegetation area, particle-collector radii ratio, and particle-water density ratio. Based on the physics of flow around cylinders, we hypothesized that the functional relationship between ƞ₀ and physical flow, sediment, and vegetation parameters would exhibit different regimes based on threshold Reynolds numbers, with different functional relationships for attached vortex, vortex shedding, and fully-developed turbulence regimes. We tested this hypothesis by synthesizing data from previous flume experiments reported in the literature and ongoing flume experiments in-house. Across these experiments, Re_s ranged from .42 to 1000. Findings generally upheld our hypothesis and revealed that the relative sensitivity of interception efficiency to the physical parameters varied as a function of flow regime. This work will enable more accurate modeling of the flux terms in sedimentation budgets, which will inform ongoing modelling and management efforts in marsh environments.