Estuaries and coastal embayments naturally replace all the water within their boundaries within a given time due to numerous processes. These processes include Tidal motions, the influx of fresh water, wind, the Coriolis effect and density gradients. The result of these processes is the removal naturally of pollutants etc. from the semi-enclosed body of water. The measure of time it takes for the removal of pollutants is described as the flushing time. Flushing analyses are extremely useful as indicators of the loading capacity of an estuary or embayment. The method detailed here examines the flushing of a semi-enclosed embayment in terms of an exchange co-efficient 'E'. It calculates values of 'E' from the volume and position of an incoming jet of water on the flood tide, the sink type flow of water on the ebb tide and volume of water common to both of them. A numerical model was used to assess the results of the flushing study analysis. Good agreement was obtained between comparisons of model results and the exchange coefficient method.
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