ABSTRACT
This chapter is concerned with the hydrodynamics of strongly tidal, well-mixed, and partly mixed estuaries. It discusses numerical solutions of the equations governing tidal flows in shallow water, and makes use of data computed for the macrotidal Bristol Channel and Severn Estuary. A semidiurnal tidal regime is considered, and the tide generating effects of the moon and sun are assumed to be negligible; generally, the important tidal motions in an estuary are caused by the oceanic tide at the entrance to the estuary. The fundamental assumptions are that the water flow is horizontal, the velocities do not vary appreciably throughout most of the water column, and the pressure at any depth is hydrostatic. Nonlinearities in the tidal dynamics not only introduce asymmetry into the elevations and currents, but also lead to a shift in mean sea level.
