The European Water Framework Directive: a new era in the management of aquatic ecosystem health?

1. The forthcoming European Commission Water Framework Directive will introduce catchment management throughout Europe, and could have major impacts on the conservation and restoration of aquatic ecosystems. The Directive is outlined, and the proposed mechanisms for determining water quality status under the Directive are described. 2. The Directive is assessed using the developing ideas of ecosystem health. These combine scientific validity with an open acknowledgement of the value judgements inherent in all assessments of ecological quality, and emphasize the importance of public involvement. 3. Permitted derogations and exemptions are identified and their likely consequences discussed. These include substantial reductions in the potential of the Directive to improve water status in some cases. Existing bioassessment methods relevant to the proposed scheme are reviewed, and the sampling and statistical implications of the Directive are explored. Much work is needed on the development of ecological classification and referencing systems if the requirements of the Directive are to be met. 4. The emphasis of the Directive on biological (and not just chemical) quality goals, and the introduction of a consideration of ecological functioning (as well as structure) is welcomed. Although the Directive requires the assessment of hydromorphological and chemical, in addition to biological, variables, in most cases biological assessment is given priority. We advocate inclusion of all three elements in quality assessments. 5. The Directive gives little advice on policy integration for catchment management at European and national levels, and fails to provide for public involvement in the process of ecosystem management. These omissions will limit the ability of the Directive to deliver ecosystem health, and need to be addressed if the goals of the Directive are to be achieved. © 1998 John Wiley & Sons, Ltd.