In the middle of the 1990s the European Environment Agency (EEA) started to develop a data collecting system for surface and subsurface water resources for assessing pressures, states and impacts on European water resources. The main objective of this system was to provide reliable, comparable, homogenous information, and support integrated environmental assessments at European level. The data collecting system for water is called Eurowaternet. The extent and information content of the network makes not only pan-European, but also regional or thematic environmental assessments possible. An extensive programme started in 1997 to support the Phare countries in their accession to the EU with implementation of this data collecting system in their countries.
The paper briefly introduces the methodology of the system, but it focuses more on the application of the system in the accession countries, highlighting, through examples, the usefulness of the implemented network and assembled database. The examples present - among several other possible ones - trends of average nutrient concentrations; relationships between catchment size and annual average nutrient concentrations; relationships between catchment size and agricultural usage.