The Dynamics of Suspended Sediment Transport in the Ribble Estuary

Velocity and turbidity were measured over a tidal cycle during both spring and neap tides in the Ribble estuary, England. The data was analysed to determine the relative magnitudes of the various components of the residual circulation and sediment flux. The Lagrangian residual circulation was found to be dominated by the influence of freshwater input to the estuary, the landward directed component of the circulation due to the Stokes drift being cancelled by the Eulerian flow induced by set-up. The dominant driving mechanism of the residual flux of suspended sediment was found to vary both spatially and over the spring-neap cycle. During the neap tide the flux in the mid estuary was negligable, however, during the spring tide landward transport of sediment by the mechanism of tidal pumping was found to be the dominant mechanism.