Dye releases, typically of rhodamine, are used in predictive studies to assess the likely dilution and dispersion of effluents in the marine environment; or postcommissioning,to verify that outfall design criteria have been met.
Dye releases can be monitored visually, or quantitatively using in-situ or sample fluorometry.
A variety of release methods can be employed, including continuous gravity feed, continuous pumped discharge via temporary pipe  and batch or continuous discharge via existing outfall .
Contour plots  and composite surface plots , are derived from a number of transects across the dye plume, and can be used to indicate the variation in dispersion patterns throughout the tidal cycle.
descriptions of plume dispersion are also used.