Tidal circulation, sediment and pollutant transport in Cádiz Bay (SW Spain): A modelling study

A numerical model to simulate the dispersion of particle-reactive tracers in Cádiz Bay (SW Spain) has been developed. It includes a hydrodynamic submodel to provide water currents, a sediment transport submodel, which provides suspended matter concentrations and sedimentation rates and the pollutant dispersion model. Pollutant exchanges between the liquid and solid phases are described in a dynamic way, using kinetic transfer coefficients. Results of the hydrodynamic and sediment transport models have been compared with observations. The contamination of sediments of the bay by fallout 137Cs has been simulated. The existence of an accumulation area in the inner bay, found in field measurements, has been reproduced by the model. Dispersion experiments for Zn and 226Ra have also been carried out. Flushing-times of the inner bay have been finally determined through numerical experiments.