Estuaries present complex ambient environments to challenge the mixing zone analyst. The confluence of fresh and marine waters along with influence of atmospheric forcings (e.g. winds, waves) and unsteady tidal currents can create complex local ambient velocity and density fields.
Estuaries are important production areas for fish and shellfish. Shellfish contamination from municipal wastewater discharge (accidental or upset) is of particular concern. Also, dredging operations are common practice in transportation infrastructure construction and maintenance.
Ambient current and density field data in oceans and estuaries can be complex. Detailed hydrographic data on bathymetric, velocity, salinity, and density profiles is recommended for regulatory mixing zone analysis.