Évaluation de l’état des eaux littorales selon la Directive Cadre sur l’eau

Commissariat général au développement durableSep 13, 2019

Le bon état des eaux littorales est essentiel pour l’équilibre biologique des écosystèmes marins, la reproduction des espèces et les activités économiques (pêche, conchyliculture, tourisme...). L’état des eaux littorales est dépendant de nombreuses activités humaines. Sur le littoral et dans les terres, ces activités sont susceptibles de le dégrader. Au sens de la Directive Cadre sur l’eau (DCE), l’évaluation de l’état des eaux littorales comprend deux aspects : l’état écologique et l’état chimique. Outre le fait d’améliorer les connaissances, ces évaluations sont réalisées dans le but d’attendre le bon état des masses d’eau d’ici 2021 ou au plus tard en 2027.

Good status of coastal waters is essential for the biological balance of marine ecosystems, species reproduction and economic activities (fishing, shellfish farming, tourism...). The status of coastal waters depends on numerous human activities. On the coast and in inland areas, these activities are likely to degrade it. Under the Water Framework Directive (WFD), the assessment of coastal water status comprises two aspects: ecological status and chemical status. Beyond improving knowledge, these assessments are carried out with the aim of achieving good status of water bodies by 2021 or at the latest by 2027.

3 chapters

General Overview
Coastal water categories and districts
• The Water Framework Directive, WFD (2000/60/CE), applies to inland waters and coastal waters. It defines two categories of coastal waters: coastal water bodies and transitional water bodies. • Coastal water bodies are marine waters situated between the baseline (low water mark for lightly indented sectors) and a distance of one nautical mile. Transitional water bodies roughly correspond to estuaries and Mediterranean lagoons, between freshwater and saltwater. • The WFD recommends working at the scale of 'river basin districts'. In total, 14 river basin districts are established in France: 9 in mainland France and 5 for overseas territories, one per overseas department.
Good status and assessment
Under the WFD, good water status is defined as the return to a natural reference situation to be achieved by 2021 or at the latest by 2027. In the framework of WFD implementation, water status assessments are carried out by Water Agencies and Offices using data from the monitoring program.
Ecological and chemical status
• The status of a coastal water body comprises two aspects: • ecological status, evaluated on 6 classes: very good, good, moderate, poor, bad and unknown; • chemical status, evaluated on 3 classes: good, bad and unknown. • Good ecological status takes into account the quality of all ecological compartments: water, fauna, flora, habitats. For artificial or heavily modified water bodies, we speak of good potential.
Substances and quality standards
• Chemical status takes into account 41 polluting substances. The assessment is based on comparison between concentration measurements within the water body and threshold concentrations determined in water or biota (environmental quality standards - EQS). • EQS is defined as the concentration of a substance or group of substances in water, sediments or biota that must not be exceeded in order to protect human health and the environment.
Ecological Status in 2015
Reference
See the dedicated fact sheet
Chemical Status in 2015
Reference
See the dedicated fact sheet

Further reading

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