The Afon Crawnon is a river in 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 ...

in the county of

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 ...

. The headwaters rise on the hills north of

Trefil Trefil is a small village in the county borough of Blaenau Gwent, south Wales. It lies at the top of the Sirhowy Valley, near to Brecon Beacons National Park. It is three miles northwest of Tredegar. With one public house, The Top House, serving ...

and flow northeast down a valley known as Dyffryn Crawnon for 7 km to a confluence with the

River Usk The River Usk (; ) rises on the northern slopes of the Black Mountain (''y Mynydd Du''), Wales, in the westernmost part of the Brecon Beacons National Park. Initially forming the boundary between Carmarthenshire and Powys, it flows north int ...

just west of Llangynidr. The valley is notable for being at the centre of a major green energy initiative known as The Three Green Valleys project and which involves the construction of several micro-hydro schemes. Dyffryn Crawnon is translated from Welsh to mean "Valley of the Garlic River".

Geology

The river flows through a valley carved into the mudstones and sandstones of the

Old Red Sandstone Old Red Sandstone, abbreviated ORS, is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the eastern seaboard of North America. It ...

laid down during the

Devonian period The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding C ...

.British Geological Survey 1:50,000 map sheet 232 'Abergavenny' & accompanying memoir

Access

The public road up the valley is effectively a cul-de-sac though numerous footpaths and bridleways climb up the sides of the valley from it. However, a vehicular impassable Restricted Byway (Road used as Public Path) connects to an equally difficult in law Right of way at the end of the valley, suspected to be the original line of the Brinore Tramroad. The

Beacons Way The Beacons Way (Welsh: Ffordd y Bannau) is a waymarked long distance footpath in the Brecon Beacons National Park, Wales. It is a linear route which runs for east to west through the National Park, and passes many of the most important landmar ...

skirts the northern edge of Dyffryn Crawnon.

References

{{DEFAULTSORT:Crawnon Afon Crawnon Rivers of Powys Rivers of the Brecon Beacons National Park