Mixing in the surf zone, i.e. in the water between the line of breaking waves and the beach, is an interesting problem because of the many processes which can produce mixing. It is also of considerable relevance because many costal discharges in Australia enter the ocean through an outlet in the surf zone, in many cases extending only to low water level. A variety of empirical and theoretical approaches can be used to describe the mixing and subsequent dilution of these discharges. The empirical approaches involve making a summary of one or more experiments, without recourse to any particular theory. At the other extreme, the theoretical approaches involve using the results of experiments to obtain coefficients on constants in a selected diffusion formulation. This paper leans towards the second approach with the variation that entrainment rather than diffusion is the theoretical approach which the analysis is based.