Fine settling particle transport in wetland flows: Effects of vegetation and settling velocity

Prediction of particle transport in wetland flows has numerous applications in ecological engineering practice. The present work extends earlier investigations [Guo et al., “Dispersion in a vegetated flow of solute from a continuous source with bed absorption,” J. Hydrol. 617, 129027 (2023) and Guo and Chen, “Solute dispersion from a continuous release source in a vegetated flow: An analytical study,” Water Resour. Res. 58, e2021WR030255 (2022)] to analytically examine the transport process of fine settling particles from a continuous release source in wetland flows. By including the term of longitudinal diffusion, the second-order linear ordinary differential equations are analytically solved. The solution is validated by previous numerical and experimental results. The steady-state vertical mean and two-dimensional concentration distribution are explicitly examined, along with the influence of vegetation factor (a factor which is proportional to the square root of the vegetation stress; higher canopy densities lead to higher values) and settling velocity on concentration distribution. Results show that the steady-state concentration field reaches the stable value at the downstream dimensionless location of about x=0.5. The stable concentration value is larger with the smaller value of vegetation factor. The two-dimensional concentration field illustrates a layered distribution and more particles are concentrated on the bed wall layer under the effect of settling velocity. The stable vertical concentration profile is analogous to the zeroth-order eigenfunction. The steady vertical concentration solution can be used to predict the suspended sediment concentration profile. The findings reveal potential applications in environmental and industrial settings, such as wetland soil and water conservation, as well as ecological restoration.