Seawater intrusion into river mouths

Abstract

A hydrodynamic theory of seawater intrusion into river mouth is presented with an application to the Kem R. mouth in the White Sea. An analytical approach is proposed for determining the thickness of seawater wedge in the mouth section instead of the empirical Keilegan formula. It is shown that the surface of the salinity wedge can have segments with different curvature signs. Explanations are given to the periodic appearance of large-scale steps on vertical salinity profiles in the tidal cycle, as well as the formation of internal waves on the wedge with frequencies falling beyond the range of internal waves in a nonviscous fluid.