Coedty Reservoir is a

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

Snowdonia Snowdonia or Eryri (), is a mountainous region in northwestern Wales and a national park of in area. It was the first to be designated of the three national parks in Wales, in 1951. Name and extent It was a commonly held belief that the na ...

North Wales North Wales ( cy, Gogledd Cymru) is a region of Wales, encompassing its northernmost areas. It borders Mid Wales to the south, England to the east, and the Irish Sea to the north and west. The area is highly mountainous and rural, with Snowdonia N ...

. It is fed by the waters of

Afon Porth-llwyd Afon Porth-llwyd is a river in Snowdonia in north-west Wales. It flows from Llyn Eigiau on the south-eastern edge of the Carneddau range to join the river Conwy. Its waters are trapped at Coedty reservoir before flowing down to pass under Po ...

which flows from

Llyn Eigiau Llyn Eigiau is a lake on the edge of the Carneddau range of mountains in Snowdonia, Conwy, Wales. The name ''Eigiau'' is thought to refer to the shoals of fish which once lived here. Early maps refer to it as ''Llynyga''. It is thought that ...

. The reservoir lies at a height of , and measures some in size. It contains brown trout. The original dam was built in 1924 to provide

hydro-electric power Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

to the aluminium smelting works in Dolgarrog. In 1925, the Eigiau dam broke, and the flood of water from that also burst Coedty dam. The resultant flood caused the loss of 16 lives in

Dolgarrog Dolgarrog is a village and community in Conwy County Borough, in Wales, situated between Llanrwst and Conwy, very close to the Conwy River. The village is well known for its industrial history since the 18th century and the Eigiau ...

. The dam was rebuilt in 1926, and altered again in 1956. Water from the reservoir, which has a catchment area of around 27 square kilometres, is carried via a 3 km large metal pipe down to the hydro-electric power-station in Dolgarrog.RWE Innergy - Dolgarrog site
Coedty dam is a balance tip dam; water flows from it automatically when it reaches high levels. This excess water flows into a spectacular gorge used by outdoor pursuit groups. Gorge walking here, however, can be dangerous because of the sudden releases of water from the reservoir which can occur. The eastern side of the lake is skirted by the trackbed of the former Eigiau Tramway, created to aid the construction and maintenance of Llyn Eigiau dam. Nearby the Cowlyd Tramway branched off, built to aid the construction of the dam at

Llyn Cowlyd Llyn Cowlyd is the deepest lake in northern Wales. It lies in the Snowdonia National Park at the upper end of Cwm Cowlyd on the south-eastern edge of the Carneddau range of mountains, at a height of above sea level. The lake is long and narrow ...

References

{{authority control Caerhun Dolgarrog Reservoirs in Conwy County Borough Reservoirs in Snowdonia Dam failures in Europe 1925 disasters in the United Kingdom de:Eigiau und Coedty