The MSB single-embayment model of pollution flushing from a tidal basin has been applied to Great Salt Pond on Block Island and the results compared to an unpublished Rhodamine dye study conducted in 1986. The MSB model is based on the analytical tidal prism formulation developed by Barber. Both approaches have previously been validated against physical hydraulic modelling tests conducted on an idealised constant-depth rectangular basin, and the MSB model has been found to give excellent agreement against the laboratory data. However, until this present work, the MSB model has not been applied to a real embayment.The present paper details a simulation of pollution flushing from Great Salt Pond following the release of Rhodamine dye. Results for various values of the pollution return-flow parameter, b, have been obtained and the agreement between the measured dye concentration data and the model predictions is shown to be very good for a suitably chosen value of b.