Environmental flows: the European approach through the Water Framework Directive 2000/60/EC

Περίληψη

The Water Framework Directive 2000/60/EC is primarily focused on water quality, addressing the quantity as an ancillary element towards achieving good ecological status (GES). However, recent WFD implementation reports reveal that water quality and quantity are closely interrelated and water bodies with significantly altered hydrological regime are not reaching GES. This led the European Commission to focus on hydrology and recently issued an environmental flows (eflows) Guidance Document to assist Member States in ensuring sufficient quantity of good quality water for the European water bodies. The European eflows framework requires continuous hydrological monitoring to provide supplementary information to the biological quality elements and support the implementation of specific steps: i) a preliminary risk analysis to define water bodies at risk of not achieving the WFD objectives due to hydrological alteration; ii) establishment of an extensive hydrological monitoring network; iii) water-body type-specific environmental flow assessments (EFAs) and assessment of the gap between current and reference state; iv) application of measures to restore eflows, towards a flow regime consistent with the requirements to achieve the WFD environmental objectives. A three-level approach for EFAs is proposed, including: i) preliminary desktop analyses using hydrological methods; ii) detailed assessments requiring field data collection according to the holistic approaches; iii) combination of holistic methodologies with advanced habitat modelling. The purpose of this article is to outline the European eflows framework as introduced through the recent eflows Guidance Document, to indicate the strengths/weaknesses of current WFD implementation, and to identify the European progress on EFAs and prevent possible misinterpretations, through detailed reference to heavily modified water bodies and WFD exemptions, towards a sustainable use of the European water resources.