The prediction of far-field pollutant concentrations using residual currents

The conventional method used for solute transport modelling involves the application of the two-dimensional, finite difference model, DIVAST (Depth Integrated Velocity and Solute Transport) to a waterbody. The length of time required to run the model is directly proportional to the size of the study area, therefore, for large study areas the process is extremely time-consuming. Since the majority of the run-time is spent computing the hydrodynamics it would obviously be beneficial if the solute transport module could be executed separately. This paper details the application of both the conventional DIVAST model and an independent solute transport model, which is driven by residual currents, to a waterbody, namely Killybegs Harbour, County Donegal, Ireland. The solute concentration results obtained from the residual current method are examined and compared to those predicted by the DIVAST model. The effects of varying some of the controlling parameters within the residual current solute model are also examined. The results from the residual current solute transport model and its comparison with the DIVAST model are presented and discussed.