Sustainable Use and Development of Watersheds

Part of the series NATO Science for Peace and Security Series pp 323-335

Water Framework Directive: Defining the Ecological Quality Status in Transitional and Coastal Waters

  • Sofia GamitoAffiliated withIMAR – University of Algarve

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The European Water Framework Directive (WFD) has established the concept of Ecological Quality Status (EQS) as a way to assess the biological quality of surface waters. The EQS will be mainly based upon the composition of different biological quality elements and their metrics. These are phytoplankton composition, abundance and biomass, composition and abundance of other aquatic flora and benthic invertebrate fauna. for transitional waters, the composition and abundance of fish fauna are also included.

The scientific community, together with the competent authorities of the Member States, is developing the methodologies for defining the reference conditions and the ecological status of the major water bodies in Europe. Several biotic indices are being tested and discussed for different coastal or transitional waters, based on one or more of the EQS elements of the ecosystem. The results are sometimes contradictory. The major challenge is the frontier between a “good” ecological status and a “moderate” status. If a water body is classified as “moderate” remediation measures are necessary.

Some of the biological indices are based on the relative abundance of species that are either sensitive or tolerant to increasing concentrations of organic matter. But the tolerant species may also be tolerant to natural Stressors such as low water renewal in estuaries or coastal lagoons, making it difficult to distinguish a naturally stressed habitat from an anthropogenically stressed habitat.

In this chapter some aspects of the implementation of the WFD will be discussed, with special focus on the methodologies applied in the benthic invertebrate fauna compartment in Transitional and Coastal Waters relative to the North East Atlantic Region.


Ecological quality status water framework directive macroinvertebrates transitional waters coastal waters