A steady state, length scale model and a three-dimensional stratified hydrodynamic/pollutant transport model were used to determine the pollutant distribution in a nearshore area of Lake Ontario, Canada, due to loading from Mimico Creek. The steady state model, named CORMIX3, is a knowledge based expert system intended for surface discharges subject to constant current flowing in one direction. The 3D time-dependent hydrodynamic/ pollutant transport model can simulate wind-induced circulation in the bay under both isothermal and stratified conditions. Field data taken around the mouth of Mimico Creek were compared to the models' dilutions for cases under isothermal and stratified conditions. CORMIX3 predictions agreed quite well with the 3D model's predictions as well as the field data.