Influence of River Sinuosity on the Distribution of Conservative Pollutants

Abstract

AbstractThe influence of river sinuosity on the distribution characteristics of pollutants in a wide river is investigated three-dimensionally with a numerical model. It is found that, for a meandering river, the hydrodynamic force strongly controls the distribution of a conservative pollutant in the river. Because of secondary flow at the channel bend, high sinuosity leads to a lighter-than-water pollutant concentrating more on the inner bend apex region at the surface, whereas at the deep near-bed region, it concentrates more on the outer bend apex. For a heavier-than-water pollutant gravity flows in sinuous channels, there are two unique features resulting from the super-elevation and multicell cross-sectional secondary flows with alternate circulation directions: (1) the pollutant is distributed at the bottom more on the inner bend apex region; and (2) more on the outer bend apex region at a depth corresponding to the mixing region of the bottom two secondary flow cells of opposite circulation directi...