A Note On Tidal Asymmetry In The Severn Estuary

A one-dimensional, non-linear numerical model is used to investigate the tidally averaged frictional stress and set-up of water level due to tidal asymmetry in the Severn Estuary; these quantities depend on the overtides in the region. A linearized model of the overtides is applied to calculations of the M4 currents in order to delineate the mechanisms responsible for their generation. The relative importance of individual non-linear mechanisms to the tidally averaged stress and set-up is determined; these mechanisms are interactions between tidal flow and changes in depth or breadth over a cross-section, frictional interaction between the tidal flow and Stokes drift, interaction between the tidal fluctuations in water depth and frictional retardation and non-linear advection.

Simulating The Impact Of Technological-Change On Dissolved Cadmium Distribution In The Severn Estuary

An estuarine model is described which computes the dispersive and advective properties of the Severn Estuary. It was calibrated and validated using 50 measured salinity distributions and then used to predict the magnitude and sitings of the major inputs of dissolved cadmium levels throughout the estuary. The results provided an impetus for implementing tighter controls on effluents and for improving estimates of cadmium discharges from industrial sources. The model has also been used to investigate the sensitivity of the estuarine system to changes in dispersion; by considering large reductions in the dispersion coefficients it is hoped that the results might be indicative of the environmental consequences following the construction of a tidal power generating scheme.