Portal de Periódicos da CAPES

Depth-mean tidal current and sediment concentration relationships in three partially mixed estuaries

1991; Elsevier BV; Volume: 32; Issue: 2 Linguagem: Inglês

10.1016/0272-7714(91)90011-y

1096-0015

John R. West, A. Y. Sangodoyin,

Coastal and Marine Dynamics

Observations of the suspended solids concentration, salinity, velocity and other hydrodynamic parameters are presented for King's Lynn (Great Ouse), Halton Quay (Tamar) and three stations (Tal-y-Cafn, Dolgarrog and Trefriw) on the Conwy estuary. Single semi-diurnal tidal cycles were studied at King's Lynn, Halton Quay and Trefriw, two tidal cycles at Dolgarrog and several at Tal-y-Cafn. The field data were further analysed to determine errors that may have arisen from the use of simple empirical equations for particulate concentration in mathematical models. Results showed that empirical functions Cd(Ud) are reasonable where erosion and deposition mechanisms dominate. Average deviation values of up to 100 mg l−1 in the range up to 500 mg l−1 were recorded due to a variety of mechanisms, including acceleration-deceleration, bed erosion, particle deposition characteristics and advection. The inhibiting effect of vertical solute-induced density gradients on particulate transport processes was found to be significant, with a reduction of particulate concentration of the order of 50% when averaged over a flood and ebb tide. It would appear that most progress in improving the predictive capability of mathematical models would be achieved by firstly incorporating vertical density gradient effects and then considering which of the other factors given above are important at a general point in time or space.