Siltation by sediment-induced density currents.

This paper describes the results of numerical experiments with a three-dimensional hydrodynamic and mud transport model in which sediment–fluid interaction is taken into account through the effects of hindered settling, buoyancy destruction in the turbulence k–ℇ model and sediment-induced barocline pressure gradients in the momentum equations. The model was applied to a schematic case representing a coastal area with a tidal river, navigation channel and harbour basin, and a real-world case, viz. Rotterdam harbour area in The Netherlands. The results show that the sediment transport into the harbour area, and subsequent siltation rates, increase by a factor 3 to 5 due to the sediment–fluid interaction. It is shown that the larger contribution stems from an increase in vertical gradients in suspended sediment. [ABSTRACT FROM AUTHOR]