The thematic report no. 16 on Estuaries as part of the Quality Status Report 2009 (QSR 2009) provides an overview of the present status of the estuaries in the Wadden Sea area, based on the Trilateral Monitoring and Assessment Program (TMAP) and further data sources from trilateral partners. This status review includes aspects like ecological status, assessment, protection and policy and management.

From the QSR 2009, thematic report 16, Estuaries:

Estuaries can be defined as tidally influenced transition zones between marine and riverine environments. However, several definitions in the scientific literature as well as in conventions and directives exist (see box below), especially in defining the down and the upstream border. The definition within the framework of the Habitats Directive (HD) corresponds approximately to the WFD definition (estuaries are called “transitional waters” in the WFD). Especially the trilateral definition is excluding some areas at the downstream border compared to the WFD and HD definition. Most definitions exclude the freshwater tidal reaches, although they form an integral part of the estuarine ecosystem (Fairbridge, 1980; Schuchardt et al.,1993a). However, in the present review the tidally influenced freshwater reaches are included. Laterally all areas up to the main dike or, where absent, the spring high tide water line, are included. According to the above definition, there are five estuaries in the Wadden Sea region: the Varde A estuary in Denmark and the Eider, Elbe, Weser and Ems estuaries in Germany. The Eider estuary has not been included in the Leeuwarden definition (Leeuwarden Declaration, 1994) due to the storm surge barrier. In terms of structure and function, however, it should be included. [….read more]

Quality Status Report 2009: Thematic Report No. 16: Estuaries  (Schuchardt & Scholle)
Quality Status Report 2004: Chapter 10: Estuaries (Essink et al.)