Transitional (estuarine) and Coastal Water Quality
The Environmental Protection Agency undertakes surveys of the water quality of estuaries and near shore coastal waters. under the Water Framework Directive.
These records form an integral part of the analysis work carried out by the EPA under the guise of the EU Water Framework Directive (WFD) Monitoring Programme.
A Trophic Status Assessment Scheme (TSAS) for the classification of these waters has been developed.The scheme, which was designed to capture the cause-effect relationship of the eutrophication process as defined in the Urban Waste Water Treatment and Nitrates Directives (Council of the European Communities (CEC), 1991a, 1991b) comprises the following criteria:
- Enrichment of water by nutrients (as indicated by measurement of dissolved inorganic nitrogen and phosphorus concentrations)
- Accelerated growth of algae (mainly as indicated by measurement of chlorophyll concentrations) and
- Undesirable disturbance (as indicated by measurement of oxygen status).
Threshold values in respect of each of the above criteria were derived with reference to levels that are typically observed in waters with very low levels of pollution or nutrient enrichment.
Trophic classification is defined as Unpolluted, Intermediate, Potentially Eutrophic and Eutrophic.