Plynlimon research catchments: river flow (Severn at Hafren site)

The Plynlimon research catchments lie within the headwaters of the River Severn and the River Wye in the uplands of mid-Wales. Intensive and long-term monitoring within the catchments underpins a wealth of hydrological and hydro-chemical research. Monitoring is funded by the Centre for Ecology Hydrology, and is ongoing since 1968. The combined datasets include river flow; rainfall, cloud and stream hydro-chemistry; meteorology; and a variety of detailed spatial datasets representing the topography, soils and rivers of the catchments. This dataset represents 15 minute river flow data measured at the Severn at Hafren site from 1976. The catchment encompasses the headwaters of the River Severn and has an area of 3.6 km2. The station is registered within the National River Flow Archive as 54091. The upper third of the catchment is peat moorland and the lower two thirds has steep incised valleys with mature coniferous plantation. The catchment has a high annual rainfall (~2600mm). The gauge is a rectangular side contracted critical depth flume. The geology is Palaeozoic shales, grits and mudstones.