Integrated Hydrological Units of the United Kingdom: Hydrometric Areas without Coastline

This dataset is part of Integrated Hydrological Units (IHU) of the UK, a set of geographical reference units for hydrological purposes including river flow measurement and hydrometric data collection. Hydrometric Areas are either integral river catchments having one or more outlets to the sea or tidal estuary, or they may include several contiguous river catchments having topographical similarity but separate tidal outlets. Hydrometric Areas are the coarsest units of the IHU in terms of spatial resolution. This dataset represents the same entities as the Hydrometric Areas with Coastline. The coastline of Hydrometric Areas without Coastline follows the boundaries of the CEH Integrated Hydrological Digital Terrain Model, from which IHU were derived, while the coastline used in Hydrometric Areas with Coastline was derived from Ordnance Survey data. The Hydrometric Areas without Coastline currently covers Great Britain only as no dataset with river geometries and names with suitable detail is available for Northern Ireland.