Analyzing solute transport in modeled wetland flows under surface wind and bed absorption conditions

Abstract

Both surface wind and bed absorption can greatly impact the pollutant dispersion processes, however, the two factors are not jointly considered in existing models due to the intricacy of analyzing the simultaneous influence of surface wind shear and bottom bed absorption. In this work, a multi-scale approach is employed to formulate the environmental dispersion process with both factors considered jointly within wetland flows. By adopting this method, the effect of wind and bed absorption on vertical concentration distribution and longitudinal concentration distribution are discussed. To visualize the results, the flow velocity contours under different wind conditions (i.e. upstream wind and downstream wind), the pollution concentration distributions versus time and spatial position, and the spatial contaminant cloud contours are presented. Moreover, numerical experiments of the interested scenarios are presented to verify the accuracy of the analytical method. The comparison shows that the results of the proposed multi-scale method agrees well with the dataset generated numerically. Finally, the multi-scale method in this work is compared to the Aris? concentration moment method in the literature by setting the bed absorption rate to zero. The comparison shows that the present model can reduce the substantial integration processes and derive accurate spatial concentration profiles.