The Water Framework Directive aims to protect the physical and biological integrity of all aquatic ecosystems and hence establish a basis for moving towards sustainable water use. The integrated and ecologically oriented assessment of the surface water status with its corresponding objectives are central instruments. The environmental objectives are set out in Article 4 of the WFD. The overall objective is a ‘good status’ to be achieved for all waters by Dec 2015.
For surface waters, ‘good status’ comprises a good ecological as well as chemical status. Ecological status is determined by a set of biological, hydro-morphological (e.g. the habitat conditions) and physico-chemical quality elements. The point of reference is given by the biological parameters of undisturbed waters. These are waters with only ‘very minor’ human impacts. The good chemical status is determined by existing surface water quality standards, and by new standards for pollutants relevant at EU level (’priority substances’), and national standards for pollutants relevant at national or regional level.
For groundwater meanwhile, ‘good status’ is determined by a good quantitative and chemical status. Good quantitative status is achieved when the abstraction is less than the natural recharge and additionally sufficient water is available for surface waters and groundwater-dependent terrestrial ecosystems to avoid any significant damage to them. Good chemical status is achieved when existing quality standards are met, e.g. on nitrates and pesticides, and when any chemical contamination has no significant negative impacts on surface waters or dependent terrestrial ecosystems and allows safe drinking water supply.
This ‘integrative’ approach, which extends current chemical water quality targets to water quantity, habitat quality and biological targets, is an improvement in the protection of our aquatic environment. Under the WFD, waters have to be protected and enhanced in a more ‘holistic’ manner. This will require rehabilitation measures such as the provision of ecologically oriented water flows to support natural biodiversity. The risks stemming from chemical pollution not covered by traditional monitoring (because of its complexity or synergies) should now be detected through the required ecological assessment.
In parallel to the good status objective, Article 4 of the WFD also calls for:
- Prevention of any further deterioration in the status of surface and groundwater;
- A progressive reduction in pollution from priority substances and a phasing out of emissions from priority hazardous substances for surface waters; and
- A progressive reduction in groundwater pollution, in order to reverse any significant and sustained upward trend in the concentration of any pollutant.
The first is clearly a stand-still clause to avoid the repetition of past water management errors and is logically the first measure needed to ensure that the objectives can be achieved. Clauses 2 and 3 establish a modern and precautionary pollution control in order to support the achievement of the ecological objectives, recognising that our knowledge of the causal relationship between chemical contamination and biological reaction is limited.
The stated aim of phasing out the emission of priority hazardous substances which is independent of whether there is scientific proof of specific environmental damage or not is novel and is the legal transposition of a European Commission and Member States commitment under the 1998 Convention for the protection of the North-East Atlantic.
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