Lagrangian Transport Model for Estuaries

Abstract

A two‐dimensional (in a vertical plane), nonlinear model is used to analyze tide‐induced mean currents in shallow estuaries forced with tides of significant amplitude. The model is first verified by comparing its results with known analytical solutions of Lagrangian currents in a uniform and homogeneous estuary. The Lagrangian velocity fields are derived from the computed mean Eulerian and Stokes velocities in the estuary. A set of model experiments is performed to investigate the influences of tidal forcing, density gradients, and topographic variations on the mean circulation in tidal channels. It is shown that the tide‐induced transport opposes density‐induced transport in tidal rivers. Model sensitivity analysis indicates that for mean estuarine circulation studies, it is essential to include the coupled effects of density and tides active in the domain of interest.