Afon Rheidol is a river in Ceredigion, Wales, 19 miles (31 km) in length. The source is Plynlimon. Receiving an average annual rainfall of 40 inches (1.02 m), Plynlimon is also the source of both the Wye and the Severn.
Cwmtwrch is a village in the valley of the Afon Twrch, a right-bank tributary to the Swansea Valley, Wales, some 15 miles north of Swansea. It is also the name of an electoral ward to Powys County Council.
The Black Mountain is a mountain range in South, Mid and West Wales, straddling the county boundary between Carmarthenshire and Powys, and forming the westernmost range of the Brecon Beacons National Park. Its highest point is Fan Brycheiniog at 802 metres or 2,631 ft. The Black Mountain also forms a part of the Fforest Fawr Geopark.
The River Cleddau consists of the Eastern and Western Cleddau rivers in Pembrokeshire, west Wales. They unite to form the Daugleddau estuary and the important harbour of Milford Haven.
The Afon Clun is a 14-mile (23 km) long tributary of the River Ely, in the counties of Cardiff and Rhondda Cynon Taf, Wales. Its bedrock is predominantly of sandstone. Beginning on the western slope of The Garth the river is fast-flowing, in clear shallow water with a hard substrate, flowing to the south of Llantrisant and generally west to its confluence with the River Ely at Pontyclun, falling 715 feet (218 m) over its course.
The Nant Gwys is a river flowing off the Black Mountain 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 the Afon Twrch at Cwm-twrch-Uchaf.
Fan Llia is a subsidiary summit of Fan Fawr in the Fforest Fawr section of the Brecon Beacons National Park, Wales. In common with other peaks in the Fforest Fawr uplands it lies within the county of Powys.
The Afon Tarell is a river in Powys, Wales, which rises to the west of the Brecon Beacons in Brecon Beacons National Park and flows north, then north-east, for 12 miles (20 km) into the River Usk.
Mynydd Llangynidr is a mountain in the Brecon Beacons National Park largely in the county of Powys, south Wales. Its southern slopes extend into the northernmost parts of the county borough of Blaenau Gwent. It is named from the village of Llangynidr which sits in the valley of the River Usk to the north of it. It is essentially an undulating plateau rising in the west to a height of 557m at Garn Fawr at OS grid ref SO 123151. A secondary high point is achieved at a point marked by a trig point at SO 147159. To the north the hill overlooks the valleys of Dyffryn Crawnon and Cwm Claisfer, themselves tributary valleys of the Usk. The shallow upper valley of the Ebbw River reaches into the plateau in the southeast whilst the upper reaches of the Sirhowy Valley and its tributary the Nant Trefil define its western margins. A further tributary, the Nant Milgatw, reaches in from the south whilst the sharp edge of Rassau Industrial Estate also defines a part of its southern margin. Passing east across the B4560, the hill merges with Mynydd Llangatwg which has a similar character.
The Afon Sawdde is a river in the county of Carmarthenshire, Wales. For most of its course it flows through the Brecon Beacons National Park and Fforest Fawr Geopark.
Tair Carn Uchaf is a hill in the Brecon Beacons National Park in the county of Carmarthenshire, Wales. Its summit sits atop a plateau-like ridge at 482 metres (1,580 ft) above sea level and is marked by one of the three huge cairns which give the mountain its name.
Waun Lefrith is a top of Picws Du and is also the westernmost of the Carmarthen Fans, a group of peaks within the Black Mountain of the Brecon Beacons National Park. It lies within Carmarthenshire, Wales. The summit plateau of the mountain reaches a height of 2221 feet above sea level. Picws Du and Fan Foel are the other, higher summits of the Carmarthen Fans. The glacial lake of Llyn y Fan Fach dominates the panorama to the north of the peak. Beyond the lake to the north lies the Usk Reservoir and then the Cambrian Mountains on the horizon. Swansea Bay and the Bristol Channel are visible to the south across the undulating dip slope of the mountain. The Towy (Tywi) valley lies to the west, with Llandovery and Llandeilo as important market towns nearest to the hills.
Penmoelallt or Onllwyn is a hill in the northern part of the county borough of Rhondda Cynon Taff in south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. To its east lies the deep valley of Cwm Taf and to its north a rather shallower valley in which the Nant Cadlan originates. To the west is the hill known as Mynydd-y-glog and to the south are slopes draining into the River Taff and the Afon Cynon. The hill culminates in a broken plateau with several knolls rising above the 420m contour. Its afforested nature makes it difficult to determine the precise location of its highest point but this probably lies somewhere around OS grid ref SO 003096. Older maps indicate a spot height of 1376 ft above sea level at SO 000090.
The Afon Hydfer is a short river in Powys in the west of the Brecon Beacons National Park, south Wales. Its headwaters rise on the northeastern slopes of the Black Mountain as the streams named Trinant, Nant y Cadno, Nant yr Erydr and Crognant, joining to flow down Cwm yr Afon on the western edge of Glasfynydd Forest. The river turns east at Blaenau Uchaf, then northeast through Cwm Hydfer and joins the River Usk just below Pont ar Hydfer. Other tributaries of the Hydfer include the streams of Nant Cil-y-clawdd, Nant Crinog and Nant Meity.
Waterfall Country is a name often given to the upper reaches of the Vale of Neath in South Wales. The tourist area around the head of the valley has an unusually large number of publicly accessible waterfalls. The area is not officially defined but generally includes the group of falls on the Nedd Fechan, Pyrddin, Hepste and Mellte rivers, all of which lie between the villages of Pontneddfechan and Ystradfellte in the Brecon Beacons National Park.
The Afon Brân is a tributary of the River Towy in mid Wales. Its headwaters rise in Irfon Forest in the northeastern corner of Carmarthenshire as the Cynnant Fawr and Afon Lwynor and the river assumes the name of Afon Brân at their confluence to the north of the village of Cynghordy. Its major tributary is the Afon Gwydderig which joins it at Llandovery. Other tributaries include the Nant Bargod, Cynnant Fach, Afon Gwyddon, Nant Hirgwm, Nant Cwm-neuadd, Bawddwr and Afon Crychan with its own minor tributary the Afon Dulais.
Cwm Twrch is a Site of Special Scientific Interest (SSSI) in Carmarthenshire, Wales.
The bedrock geology of Carmarthenshire in west Wales consists largely of Palaeozoic age sedimentary rocks. Unconsolidated deposits of Quaternary age in Carmarthenshire include a dissected cover of glacial till, valley floor alluvium and some scattered peat deposits in both upland and lowland settings. There are extensive beach and tidal flat deposits along the Carmarthenshire coast. The exploitation of the county's mineral riches, particularly coal and limestone, was a key part of the local economy through much of the nineteenth and twentieth centuries.
