Analysis of contaminant dispersion in open channel with two streambank-absorption boundaries

Boundary absorption intensity can affect the contaminant depletion capacity within rivers, and the process of spatial contaminant cloud expansion is complicated with the consideration of irreversible absorption boundaries at riverbanks. Nonuniformity of concentration distribution appears in spatial concentration distribution, especially in the transverse direction, which is caused by the absorption capacity difference between two riverbanks. A model for illustrating the performance of environmental dispersion with two irreversible absorption banks in 2D space is given in this work. Furthermore, the position of the maximum concentration distributions shifts within the transverse directions with the change of the absorption intensities at two boundaries. The overall absorption capacity would also be affected by the ratio of two absorption intensities at the left and right riverbanks. The residual mass is left with a greater variation in the two bank-absorption intensity ratios. A detailed analysis of the spatial concentration distribution and contaminant depletion capacity with two bank-absorption boundaries would contribute to the construction of a wetland for water treatment. With a certain absorption capacity in total, the transverse distribution of concentration gets more heterogeneous as the ratio deviates from 1gradually, and the transverse concentration distribution appears to be symmetric to the center (0.5W) when the ratios of absorption intensities at two stream-banks are in accord with β₀ : β₁ = β₁ : β₀. The novelty of this work is to provide the analytical solution of two-dimensional concentration distribution with the ratio of two stream-bank absorptions, furthermore, a linear fitting equation([Formula: see text]) for crest position of transverse concentration distribution is given to show the shifting process of spatial contaminant cloud with the change of two stream-bank absorption ratios, and the correlation coefficients are all above 0.99, illustrating a good fit for the results.