Problems related to water mixing becoming more important, especially when it comes to evaluate the impact of a domestic, industrial or thermal discharge on the receiving stream. The need to predict the water quality according to the rate of the dispersion of pollutants has pushed researchers to develop several mixing models. These models, developed from the Advection–Dispersion Equation, are aimed to identify and predict the spatiotemporal evolution of the concentration of a given pollutant.
Since streams often have a much greater width than the depth; vertical mixing of pollutants is complete and transverse mixing is predominant. Away from the injection point; the problem becomes one-dimensional; is the longitudinal dispersion.
In this article, the transverse mixing problem has been studied in a trapezoidal channel, several concentration measurements in the longitudinal and lateral direction of the flow were performed, and for different scenarios of injections of pollutant in the channel, the results obtained show a great influence of the flow and quantity of pollutants on the transverse mixing phenomenon.