Water Framework Directive (WFD) River Waterbodies (RWB) are the management and reporting units for the WFD. WFD RWB is a polyline shapefile dataset which is formed from a water flow routes dataset. Waterbodies are assigned types depending on their likely WFD status classification and physical and biological characteristics (typology). This is in line with European Commission CIS guidance on delineation of waterbodies. Since each RWB is attributed with a unique identifier (EU_CD), this dataset can be linked directly to other WFD data sources such as physical characteristics, risk, classification and other objectives. In some karst areas, this layer contains indicative underground flow connections between surface rivers. Such lines are indicative only and should not be taken to infer the presence of an underground river at a particular location. The appropriate Geological Survey Ireland data sets should be consulted where underground flows or connections are known or suspected.