Elan Valley Reservoirs

The Claerwen reservoir and dam in Powys, Wales, were the last additions to the Elan Valley Reservoirs system built to provide water for the increasing water demand of the city of Birmingham and the West Midlands. The dam is built mainly of concrete, with the exterior dam face in dressed stone. The dam is a gravity dam built upon solid rock foundations as the pressure of the reservoir behind should be in equilibrium with the total weight of the dam itself thus causing complete stability. The Claerwen dam was finished in 1952 and was given a late Victorian effect so that it blended in with the earlier dams in the valley. It was necessary to employ the services of Italian stonemasons as British ones were still at work in London during the post-war rebuilding process of the late 1940s. The dam took six years to complete and was almost twice the size of the other dams in the Elan valley. The Claerwen reservoir is almost the size of all the other reservoirs in the Elan Valley system combined. Officially commissioned by Queen Elizabeth II in 1952, it was one of her first royal engagements as monarch. Water from the reservoir flows via an underground aqueduct to the Caban-coch reservoir from which it is abstracted through a gravity aqueduct to Birmingham.

The Claerwen Fault is a major SW-NE trending fault in central Wales. It was active as a normal fault during deposition of Late Ordovician to mid-Silurian sedimentary rocks, downthrowing to the northwest. The estimated throw on the fault increases from about 100 m at a shallow level to about 1000 m at depth. There is no discernible change in the grade of metamorphism associated with the Caledonian Orogeny across the fault, suggesting that it was not reactivated later.

The Craig Goch Dam, often called the Top dam, is a masonry dam in the Elan Valley of Wales and creates the upper-most of the Elan Valley Reservoirs. Construction on the dam began in 1897, and it was completed in 1904. The primary purpose of the dam and the other reservoirs is to supply Birmingham with water. In 1997, a 480 kW hydroelectric generator began operation at the dam.

The Principality of Wales (Welsh: Tywysogaeth Cymru) was originally the territory of the native Welsh princes of the House of Aberffraw from 1216 to 1283, encompassing two-thirds of modern Wales during its height of 1267–1277. Following the conquest of Wales by Edward I of England of 1277 to 1283, those parts of Wales retained under the direct control of the English crown, principally in the north and west of the country, were re-constituted as a new Principality of Wales and ruled either by the monarch or the monarch's heir though not formally incorporated into the Kingdom of England. This was ultimately accomplished with the Laws in Wales Acts 1535–1542 when the Principality ceased to exist as a separate entity. The Principality was formally founded in 1216 by native Welshman and King of Gwynedd, Llywelyn the Great who gathered other leaders of pura Wallia at the Council of Aberdyfi. The agreement was later recognised by the 1218 Treaty of Worcester between Llywelyn the Great of Wales and Henry III of England. The treaty gave substance to the political reality of 13th-century Wales and England, and the relationship of the former with the Angevin Empire. The principality retained a great degree of autonomy, characterized by a separate legal jurisprudence based on the well-established laws of Cyfraith Hywel, and by the increasingly sophisticated court of the House of Aberffraw. Although it owed fealty to the Angevin king of England, the principality was de facto independent, with a similar status in the empire to the Kingdom of Scotland. Its existence has been seen as proof that all the elements necessary for the growth of Welsh statehood were in place.The period of de facto independence ended with Edward I's conquest of the principality between 1277 and 1283. Under the Statute of Rhuddlan, the principality lost its independence and became effectively an annexed territory of the English crown. From 1301, the crown's lands in north and west Wales formed part of the appanage of England's heir apparent, with the title "Prince of Wales". On accession of the prince to the English throne, the lands and title became merged with the Crown again. On two occasions Welsh claimants to the title rose up in rebellion during this period, although neither ultimately succeeded. Since the Laws in Wales Acts 1535–1542, which formally incorporated all of Wales within the Kingdom of England, there has been no geographical or constitutional basis for describing any of the territory of Wales as a principality, although the term has occasionally been used in an informal sense to describe the country, and in relation to the honorary title of Prince of Wales.

The Elan Valley (Welsh: Cwm Elan) is a river valley situated to the west of Rhayader, in Powys, Wales, sometimes known as the "Welsh Lake District". It covers 70 square miles (180 km2) of lake and countryside. The valley contains the Elan Valley Reservoirs and Elan Village, designed by architect Herbert Tudor Buckland as part of the same scheme. Elan Village is the only purpose-built Arts and Crafts "Model Village" in Wales. It is also famous for its picturesque scenery. Over 80% of the valley is designated as Sites of Special Scientific Interest, and a popular cycle trail, the Elan Valley Trail, makes a loop from Rhayader around the reservoirs. Part of the trail overlaps with a spur of National Cycle Route 81 (Lon Cambria). As of 2015 it is an International Dark Sky Park.

Elan Village (Welsh: Pentre Elan) is a small purpose-built community in Powys, Wales. It was designed by architect Herbert Tudor Buckland as part of Birmingham Corporation's scheme to construct a series of water supply reservoirs in the Elan Valley between 1892 and 1904. It housed workers and their families responsible for maintaining the scheme's dams and the filtration systems. Elan Village is the only purpose-built Arts and Crafts "Model Village" in Wales. It is served by the B4518 road which runs three miles southwestwards from Rhayader to end at the village, though continuing as a minor road to Caban-coch Reservoir. The road continues over the Elenydd to Cwmystwyth and a cul-de-sac branch runs to the dam of Claerwen Reservoir. It is in the community of Rhayader.

Caeau Cnwch a Ty'n-y-graig is a Site of Special Scientific Interest in Brecknock, Powys, Wales. It occupies sloping ground on the south west side of Pen-y-garreg Reservoir in the Elan Valley. Caeau Cnwch a Ty'n-y-graig comprises four traditionally managed fields in a small valley below Craig Cnwch, near Elan Village. They provide a type of herb-rich grassland that is characteristic of the upland fringe of central Wales.

Carn Gafallt is a Site of Special Scientific Interest in Breconshire, Powys, Wales, and a hill of 466 metres (1529 feet) which is a Marilyn.

Cefn Croes is a wind farm in Ceredigion, Wales. It is located in the Cambrian Mountains on Cefn Croes mountain, 573m (1,880 ft) south of the A44 road between Aberystwyth and Llangurig, in west Wales. The construction of the wind farm commenced in February 2004, and was completed in the spring of 2005 when the 39 wind turbines started producing electricity. The maximum installed nameplate capacity is 58.5 MW.Nearby is the HuMP Y Glog (Draws Drum).

Hafod Uchtryd (English: Uchtryd summer mansion) is a wooded and landscaped estate in the Ystwyth valley in Ceredigion, Wales. Near Devil's Bridge, Cwmystwyth and Pont-rhyd-y-groes, it is off the B4574 road. Hafod Uchtryd land was within the boundaries of the Cistercian Abbey Strata Florida (Welsh: Caron-Uwch-Clawdd). Originally a hunting lodge for Welsh Chieftains, it became home to the landed gentry and the nobility. In the late eighteenth century, a celebrated landscape was created under the ownership of Thomas Johnes.The estate is in the parish of Llanfihangel y Creuddyn near Llanddewi-Brefi. Llanfihangel-y-Creuddyn was a chapel-of-ease in the parish. It was rebuilt for Thomas Johnes by James Wyatt in 1801. The estate shares a border along the Ystwyth with that of the Trawsgoed estate.

Garreg Lwyd is a hill in Mid Wales, between the towns of Rhayader and Llangurig. It rises to the east above the A470 as it follows the Wye Valley. The Bryn Titli Wind Farm is situated on an area of flatter moorland to the north-west. Red kites frequent the area.

Marteg Halt railway station was a station to the northwest of Rhayader, Powys, Wales. The station closed in 1962.