Welcome to, the knowledge base and online portal on the assessment of surface waters according to the European Water Framework Directive (WFD)!

“Gewässerbewertung” is the German term for "surface waters assessment". This homepage offers knowledge and information on the assessment of surface waters, namely rivers, lakes transitional and coastal waters according to the European Water Framework Directive (WFD)

“Water is not a commercial product like any other but, rather, a heritage which must be protected, defended and treated as such.“

This main principle of the European WFD − launched in December 2000 − constitutes a new guideline for the assessment and management of water bodies. The Directive is ought to improve and sustain the quality of ground water and the status of all surface waters − rivers, lakes, transitional and coastal waters − for future generations. The concrete goal of the Directive is to achieve and maintain a ‘good ecological status’ of natural water bodies and a ‘good ecological potential’ of heavily modified water bodies (HMWB) and artificial water bodies (AWB), respectively, until 2015 and, after extension of the deadline until 2027.

For the first time, ecology and the natural functional capability of water bodies have been put into focus, which, however, must not have significant implications on human water uses such as drinking water supply and navigation. Because both ecological concerns and the human water uses constitute the basis for a sustainable management in line with the Directive.

Ecological status and potential, respectively, of water bodies are classified according to biological quality elements of the aquatic flora and fauna. These are fishes, benthic invertebrates, phytoplankton and other aquatic flora, which are known to be suitable and reliable biological indicators of a water body’s quality. For all biological quality elements, species abundance and community composition are recorded and evaluated, and in addition fish age structure and phytoplankton biomass.

Besides biological quality elements, further supporting quality elements are considered: physico-chemical, hydrological and morphological parameters. They are used for a plausibility check and the interpretation of the biological assessment results.

For the implementation of the WFD, basic information and assessment systems have been developed and compiled for all water categories - rivers, lakes, transitional and coastal waters. These include:

  • water body typologies and typological maps as a basis for the type-specific assessment
  • biological assessment systems, including the field and lab protocols for biological sampling, sample processing and mathematical calculations
  • proceedings to assess the supporting quality elements

All this information on water body assessment is now available at:!

The content of this website is extensively harmonised with the revised German surface waters regulation (“Oberflächengewässerverordnung") from June 20th 2016 (OGewV 2016). For some biological quality elements, updated versions of the assessment systems are presented. The description of the proceedings to assess the supporting morphological and hydrological quality elements is in line with the current state recommended for Germany.

All texts are downloadable as pdf documents at your individual disposal.

In addition, you will find the primary literature (partly in English language) available, as far as the copyright is not violated. Currently, the website is available in German language only. To access the English literature, please switch back to German language. Where available, you will find the literature under the menu item “Weiterführende Literatur”.