Mixing effects in the river downstream from pollution discharge point

This paper follows the propagation of pollution in a river with rectangular cross-section bed and variable cross-sectional velocity. The calculations were made for steady flows pollutant concentrations. To approximate velocity distribution set equations current vorticity functions was solved. concentrations calculated from bidirectional advection turbulent diffusion equation. Analysis leads to conclusion that effects transverse associated lateral inflow pollutants disappear relatively quickly. Therefore, cross sections further downstream point discharge can be determined quite accurately just an advection-diffusion model, no included. Such level accuracy is usually sufficient assess impact source on aquatic environment. mixing stream proceeds slowly creates large zone which (low but still significant water quality) detected cross-sections are remote point. Transverse may ignored while calculating at straight watercourse state conditions.