Source: European Parliament
Under the Water Framework Directive (WFD)[1], intercalibration pertains to ecological status. Denmark, Sweden and Germany use chlorophyll-a to assess phytoplankton biomass, a mandatory status parameter.
The Common Implementation Strategy (CIS) has produced specific guidance[2] on how to submit for approval a new or updated assessment method for items for which the intercalibration exercise has already been completed.
The assessment method submitted to the intercalibration procedure does not need to already be in use in the current River Basin Management Plans (RBMPs)[3].
Nutrient conditions are a parameter for ecological status[4]. Scientific literature has demonstrated a consistently strong link between chlorophyll-a and nutrient levels in water, suggesting the possibility of the intercalibration of chlorophyll-a based on nitrogen concentrations only, but its approval requires the scrutiny and approval by the relevant Commission experts.
To be able to demonstrate good ecological status as required under the WFD, a Member State needs to define the reference conditions of the underlying quality elements, set up a monitoring programme, and use the resulting data to carry out the appropriate assessments.
The ecological status and chemical status assessment are independent. The CIS provides guidance documents for applying the WFD.
As regards chemical status, the Commission analysis of Denmark’s third RBMPs[5] notes with concern that o nly a tiny fraction of surface waters, namely 1.7%, is in good chemical status, whereas 5.6% is in poor status and for 92.7% the chemical status is classified as unknown.
For almost all coastal waters, the status is known: 93% of them are in poor chemical status[6].
- [1] Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, OJ L 327, 22.12.2000, p. 1-73, as amended by Commission Directive 2014/101/EU of 30 October 2014, OJ L 311, 31.10.2014, p. 32-35.
- [2] https://op.europa.eu/en/publication-detail/-/publication/43c0f50e-5df6-4c1a-bdba-4a3b7d249799
- [3] https://environment.ec.europa.eu/topics/water/water-framework-directive_en#state-of-play-of-3rd-rbmp-adoption-in-eu-27
- [4] While not the case for surface water bodies, nitrates are a parameter for the chemical status of groundwater.
- [5] https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=SWD%3A2025%3A34%3AFIN&qid=1738746144581
- [6] Only two coastal waters (1.8%) are reported with chemical status ‘unknown’.