The Nant Llech is a minor river in

Powys Powys ( , ) is a Principal areas of Wales, county and Preserved counties of Wales, preserved county in Wales. It borders Gwynedd, Denbighshire, and Wrexham County Borough, Wrexham to the north; the English Ceremonial counties of England, ceremo ...

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

and which lies wholly within the

Brecon Beacons National Park Brecon Beacons National Park, officially named Bannau Brycheiniog National Park (), is a National parks of the United Kingdom, national park in Wales. It is named after the Brecon Beacons (), the mountain range at its centre. The national park ...

. The name means 'slab stream', presumably in reference to the sandstones across which it runs. Its headwater streams, the Nant Llech Pellaf and the Nant Llech Isaf join forces at Blaen Llech and then continue westwards as the Nant Llech for 3 km / 2 mi to a confluence with the

River Tawe The River Tawe (; ) is a long river in South Wales. Its headwaters flow initially east from its source below Llyn y Fan Fawr south of Glasfynydd Forest, Moel Feity in the Black Mountain (range), Black Mountains, the westernmost range of the ...

just east of the village of

Abercraf Abercraf (also ; or Abercrave) is a village in Powys, Wales, in the community of Ystradgynlais and within the historic boundaries of the county of Brecknockshire. A distinct dialect of English is spoken in the village, as well as the Welsh lang ...

Waterfall

The most famous feature of the river is

Henrhyd Falls Henrhyd Falls ( Welsh: ''Sgwd Henrhyd'') in the Brecon Beacons National Park, Wales, is the tallest waterfall in southern Wales, with a drop of . It lies on National Trust land, in the county of Powys. The nearest settlement is Coelbren, on the ...

(Sgwd Henrhyd or Rhaeadr Henrhyd in

Welsh Welsh may refer to: Related to Wales * Welsh, of or about Wales * Welsh language, spoken in Wales * Welsh people, an ethnic group native to Wales Places * Welsh, Arkansas, U.S. * Welsh, Louisiana, U.S. * Welsh, Ohio, U.S. * Welsh Basin, during t ...

), a 27m/90 ft high fall where the river plunges over the edge of a band of hard sandstone known as the '

Farewell Rock The Farewell Rock is the name given to a series of sandstones at the boundary of the Coal Measures with the underlying Marros Group in South Wales. Once thought to be a single sandstone, it is now accepted that the same name has been applied to s ...

' into a deep plunge pool. The river continues below in a steep wooded gorge cut into mudstones and sandstones of the

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

age Coal Measures. The falls are owned and managed by the

National Trust The National Trust () is a heritage and nature conservation charity and membership organisation in England, Wales and Northern Ireland. The Trust was founded in 1895 by Octavia Hill, Sir Robert Hunter and Hardwicke Rawnsley to "promote the ...

which provides a free car park off the minor road between Coelbren and Pen-y-cae for visitors wanting to explore the area. A public footpath runs the length of the valley though part runs across a landslip area which has been active in recent years. The river gorge is a

site of special scientific interest A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...

. www.ccw.gov.uk Sir

William Edmond Logan Sir William Edmond Logan, FRSE FRS FGS (20 April 1798 – 22 June 1875), was a Canadian-born geologist and the founder and first director of the Geological Survey of Canada. Life William Edmond Logan was born into a well-to-do Montreal family ...

, first director of the

Geological Survey of Canada The Geological Survey of Canada (GSC; , CGC) is a Canadian federal government agency responsible for performing geological surveys of the country developing Canada's natural resources and protecting the environment. A branch of the Earth Science ...

discovered some fossil trees near the base of the falls. These are now on display outside

Swansea Museum The Swansea Museum in Swansea, Wales, UK is the oldest museum in Wales, created for and by the Royal Institution of South Wales in 1841 to house its collections and provide research and learning facilities. History Swansea Museum is the olde ...

References

{{authority control Llech Rivers of the Brecon Beacons National Park Rivers of Powys