Resumen
The European Commission Water Framework Directive (WFD) was established 16 years ago and forms the current basis for monitoring surface waters and groundwater in Europe. This legislation resulted in a necessary adaptation of the monitoring networks and programs for rivers, lakes, and transitional and coastal waters to the requirements of the WFD at German and European levels. The present study reviews the most important objectives of both the monitoring of surface waters and the principles of the WFD monitoring plan. Furthermore, we look at the changes water monitoring in Germany has undergone over the past sixteen years and we summarize monitoring results from German surfaces waters under the WFD. Comparisons of European approaches for biological assessments, of standards set for physical and chemical factors and of environmental quality standards for pollutants reveal the necessity for further European-wide harmonization. The objective of this harmonization is to improve comparability of the assessment of the ecological status of waters in Europe, and thus also to more coherently activate action programs of measures.