Dynamics of mixing in estuaries

The one-dimensional, advective-dispersive equation for a non-conservative substance is reformulated such that salinity replaces longitudinal distance as one of the independent variables. This general formulation is used to discuss the concept of concentrate-salinity mixing curves. The importance of temporal variations and loss terms in distorting these curves is illustrated by solving the transformed equation for simple cases. Procedures for measurement, interpretation and prediction of mixing curves are discussed.