Investigation of Longitudinal Dispersion Coefficient in rivers

Over the course of recent decades, agricultural and industrial activities have led to a considerable pollution in rivers. To control the river pollution level, the waste water discharge should be regulated. Pollutions have been dispersed in longitudinal, lateral, and vertical direction. The longitudinal dispersion of pollutants in river is important. In this study, a comprehensive equation was proposed for longitudinal dispersion coefficient using dimensional analysis. Dimensional and statistical analysis indicated that longitudinal dispersion coefficient depends on roughness coefficient and the ratio of width to depth of river. Sensitivity analysis indicated that roughness coefficient had the highest effect on longitudinal dispersion coefficient. The proposed methodology is a new approach to estimate dispersion coefficient in streams and can be implemented into mathematical models of pollutant transfer.