The River Giedd (

Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peop ...

:Afon Giedd) is a principal tributary of the

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

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

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

runs within 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 ...

and lies almost wholly within 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 ...

(Parc Cenedlaethol Bannau Brycheiniog). This river is perhaps unique in the British Isles in that there are in fact two separate rivers sharing the same name and occupying the same valley but which are not hydrologically connected. The upper Giedd rises on the southern slopes 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 ...

mountain,

Fan Brycheiniog Fan Brycheiniog is the highest peak at a height of (above sea level) in the Black Mountain (''Y Mynydd Du'') region of the Brecon Beacons National Park in southern Wales. There is a trig point at the peak and on the edge of the escarpm ...

in the Black Mountain (Y Mynydd Du) and heads south-southwest for about 3 km / 2 mi until, as it enters onto the

Carboniferous Limestone Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian Epoch of the Carboniferous Period. These rocks formed between 363 and ...

outcrop it disappears into its bed. A dry valley continues in the same direction beyond the sinks and, as it crosses the Millstone Grit outcrop, gradually acquires a stream which is joined by others to become the lower Giedd. This separate river flows for about 6 km / 4 miles, passing the small village of

Cwmgiedd Cwmgiedd is a small village beside the River Giedd within the community of Ystradgynlais, Powys, Wales. It lies 22.5 km (15 miles) north-east of Swansea and 253 km (157 miles) west of London. ''The Silent Village'', a 1943 British propa ...

, to its confluence with the River Tawe at

Ystradgynlais Ystradgynlais (, ) is a town on the River Tawe in southwest Powys, Wales. It is the second-largest town in Powys and is in the historic county of Brecknockshire. The town has a high proportion of Welsh language-speakers. The community includes ...

in the

Swansea Valley The Swansea Valley ( cy, Cwm Tawe) is one of the South Wales Valleys. It is the valley from the Brecon Beacons National Park to the sea at Swansea of the River Tawe in Wales. Administration of the area is divided between the City and County of Sw ...

Dye tracing Dye tracing is a method of tracking and tracing various flows using dye as a flow tracer when added to a liquid. Dye tracing may be used to analyse the flow of the liquid or the transport of objects within the liquid. Dye tracking may be either qu ...

in 1970 revealed that the waters of the upper Giedd which disappear into the ground at Sinc y Giedd eventually re-emerge at

Dan-yr-Ogof Dan yr Ogof (), at the National Showcaves Centre for Wales, is a long cave system in south Wales, about north of Ystradgynlais and southwest of Brecon, in the Brecon Beacons National Park. It is the main feature of a show cave complex, which i ...

and do not contribute in any way to the flow of the lower Giedd.Gascoine, W. in Ford, T.D. (ed) 1989 'Limestones and Caves of Wales' Cambridge University Press p52 The only significant tributary of the River Giedd is the Nant Cyw (translates as 'chick stream') entering on its left bank and whose two tributaries are in turn, the Nant Iar ('hen stream') and Nant Ceiliog ('cockerel stream').

References

External links

*
images of upper River Giedd

and of lower River Giedd and area on Geograph website
{{Authority control Giedd Giedd Giedd Giedd