Nant Gwys
River in Powys, Wales
From Wikipedia, the free encyclopedia
The Nant Gwys is a river flowing off the Black Mountain (Y Mynydd Du) in Powys, Wales. Its tributaries Gwys Fawr and the Gwys Fach flow south from Banwen Gwyn and Bwlch y Ddeuwynt respectively and join forces to form the Nant Gwys proper which then flows for about 5 km (3 mi) to its confluence with Afon Twrch at Upper Cwmtwrch.
The upper reaches of the river and its tributaries lie within the Brecon Beacons National Park and within Fforest Fawr Geopark.[1] The river is one of several which run down the southward directed dip-slopes of the Black Mountain passing from the Twrch Sandstone outcrop onto the mudstones of the Carboniferous Coal Measures.[2]
The name translates from Welsh as 'sow stream', presumably in reference to the neighbouring Afon Twrch or 'boar river'.