The Afon Crawnon is a river in the

Brecon Beacons National Park The Brecon Beacons National Park ( cy, Parc Cenedlaethol Bannau Brycheiniog) is one of three national parks in Wales, and is centred on the Brecon Beacons range of hills in southern Wales. It includes the Black Mountain (range), Black Mountain ...

in the county of

Powys Powys (; ) is a Local government in Wales#Principal areas, county and Preserved counties of Wales, preserved county in Wales. It is named after the Kingdom of Powys which was a Welsh succession of states, successor state, petty kingdom and princi ...

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

. 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 (; cy, Afon Wysg) 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 fl ...

just west of

Llangynidr Llangynidr is a village, community and electoral ward in Powys, Wales, about west of Crickhowell and south-east of Brecon. The River Usk flows through the village as does the Monmouthshire and Brecon Canal. It is in the historic county of B ...

. 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 Micro hydro is a type of hydroelectric power that typically produces from 5 kW to 100 kW of electricity using the natural flow of water. Installations below 5 kW are called pico hydro. These installations can provide power to an i ...

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 The Old Red Sandstone 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 northeastern seaboard of North America. It also exte ...

laid down during the

Devonian period The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wh ...

.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