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Pollution in Nearshore Waters

Coastal recreational waters should comply with the appropriate water quality standards. In Europe these standards are defined by the new EU Bathing Waters Directive (2006/7/EC). Industrial and sewage treatment works often discharge their effluent into estuarine or coastal waters. Increased awareness by both regulatory bodies and the general public has made it vital to assess the effect of pollutants within coastal waters. In numerical models of the coastal region, the flows are usually depth averaged two dimensional simulations and tidal variations are used to predict velocities. The physical dispersal of plumes from waste disposal sites in the coastal zone is then simulated using the predicted velocity distributions and an estimated mixing coefficient.

At present these models are limited in their predictive capability due to a lack of detailed understanding of the hydrodynamic processes associated with bed shear stress, turbulence and mean velocity field, resulting in an inability to distinguish between the individual contribution of wave activity and current action on the mixing processes. This proposed research will extend current research and knowledge using novel experimental techniques to elucidate physical processes and provide descriptions of the key mass exchange processes and turbulent wave velocity fields.

The provision of the new 2D wave flume facility at Warwick, together with the specialist measurement available will provide the applicants with a unique opportunity to investigate the 'finer' mixing mechanisms responsible in the nearshore region, particular emphasis would be placed on measurement of the hydrodynamics (such as the vertical variation in velocity and wave generated turbulence), which would further refine the understanding of mechanisms responsible for the mixing. The use of non-intrusive measurement systems such as a laser light sheet provides the opportunity to investigate the hydrodynamics using PIV, and the diffusion/dispersion processes using PLIF (Planar Laser Induced Fluorescence).

For more information please contact Dr Jonathan Pearson.