Hydrography of South Pass, Mississippi River

Abstract

In the lower South Pass channel, a combination of salt-water intrusion and tide dominate circulation and mixing. Seaward discharge and vertical mixing in the channel are greatest during ebbing tide, when the hydrostatic gradient is at a maximum. Direction of flow within the salt-water wedge is largely a function of tidal phase, upstream currents prevailing during flooding tide, and downstream currents characterizing ebbing tide. Bed load transport in the lower channel, particularly at low and normal river stage, is, therefore, considered to be tide dependent.