ABSTRACT
Symbols used only once are defined locally in the text. To achieve homogeneity, some symbols have been changed from those used in source publications. a wave amplitude
Subscripts b indicates condition at breaking of wave
1 INTRODUCTION
Flow of water and sediments in rivers is one-way, under the action of gravity. When rivers approach the sea they come under the influence of tidal action which initially causes periodic variations in the rate of flow and, further down the seaward course, periodic reversals imposed on the flow. Somewhere within the zone of tidal influence the fresh river waters encounter saline water and from there onwards they are influenced by differences in density over the depth and in the seaward direction. These density gradients superimpose a differential motion on the net seaward movement, seawards at the surface and landwards at the bed. The overall effect depends on the relative magnitudes of tidal influx and river discharge during a tidal cycle over unit width of the estuary and on the degree of turbulent mixing.42
