Dispersion in a vegetated flow of solute from a continuous source with bed absorption

Abstract

Predicting the dispersion process of environmental transport in wetland flows is significant to some ecological engineering applications. By extending a previous study (Guo and Chen, 2022), an analytical solution of the steady-state concentration field for solute transport from a continuous release source in a submerged vegetated flow with the effect of bed absorption is presented in this work. Results illustrate that adopting different orthogonal basis functions does not affect the result but affects the convergence rate of the solution near the release source. Under the bed absorption, concentration approaches zero at the far field. Concentration is affected by different bed absorption rates when the absorption rates are small, while it is hardly affected by different absorption rates when the bed absorption rates are large. When the release position is above the bed wall, different bed absorption rates do not affect the near field concentration where the vertical dispersion of solute has not arrived at the bed wall. Under the same bed absorption rate, concentration decays more quickly along the downstream distance when the release position is near the bed wall, but the release positions almost do not affect the downstream distance where the concentration tends to zero.