This report addresses the issue: What is a WFD compliant assessment method? This is done by focusing on the concept of the Ecological Quality Ratio (EQR). The EQR incorporates the key WFD requirements for ecological classification: typology, reference conditions, and class boundary setting. The Deliverable is targeted both to the policy makers and competent authorities implementing the Water Framework Directive and the scientists supporting them with their specific knowledge.
The Classification Guidance separates three levels in the biological assessment: the parameter level, the quality element level, and the status classification. The main conclusion is that the WFD requires classification of water bodies at the quality element level, and that the worst of the relevant quality elements determines the final classification (the “one out, all out” principle). How the different parameters within a quality element are combined is not prescribed; this can either be done by combining them in a multimetric index, or in any other way.
WFD- compliance criteria for assessment methods include reference conditions setting, definition of quality classes, and intercalibration of those boundaries. Those are currently addressed in the WFD intercalibration exercise, with a strong focus on specific quality elements and pressures. It is expected that the remaining quality elements and pressures will be addressed in the next couple of years, and that there will be a tendency from very specific, single-parameter, pressure-specific methods towards more general multimetric approaches.
Quantification of EQR uncertainty should be implemented in future assessment programs. Software like starbugs (http://www.eu-star.at/) may help in the assessment of EQR uncertainty and provides a first attempt into this direction. It should be remarked that the analysis of uncertainty of EQR classification of a given site resulting from the use of a specific assessment scheme does not reveal the (unknown) real quality class of that site. If the EQR assessment outcome can be incorporated into a modelling framework, uncertainties may be assessed through careful evaluation of model predictions.JRC.H.5-Rural, water and ecosystem resource
