Detailed River Network

The Detailed River Network (DRN) is the only large-scale, accurate and fully attributed digital river centreline covering England and Wales. The DRN is partially captured from the water features theme of the OS MasterMap Topographic layer and built into a network using automated rules and supplemented with Environment Agency field surveys. Other input datasets and extensive local Environment Agency staff knowledge has been used to augment the core geometry to incorporate critical spatial detail and attribution, such as flow direction and path, not available from the OS mapping and to verify the accuracy of the centreline itself. The dataset has full-feature network geometry cross-referenced with OS MasterMap following Digital National Framework principles. The DRN includes a thematic layer titled Indicative Main River that has been created by an automated query comparing the official Main River layer with the DRN. The Indicative Main River thematic layer should only be used as a guide as to whether a watercourse is designated as a Main River (later versions will formalise this association along with WFD river Waterbodies).