Elan Valley Reservoirs

Elan Valley Reservoirs
Caban-coch Reservoir c. 1963.
Location of the reservoirs in Wales.
Location of the reservoirs in Wales.
Elan Valley Reservoirs
LocationElan Valley in Powys, Wales
Coordinates52°16′20″N 3°41′20″W / 52.27222°N 3.68889°W / 52.27222; -3.68889
Lake typeReservoirs
Primary inflowsRiver Elan
River Claerwen
Primary outflowsElan aqueduct
River Elan
Managing agencyDŵr Cymru Welsh Water
Built1893
First flooded1896
Max. length5.9 km (3.7 mi)[1]
Max. width0.5 km (0.31 mi)[1]
Surface area606 ha (1,500 acres)[1]
Average depth41.5 m (136 ft)
Max. depth56 m (184 ft)[1]
Water volume99,499,000 m3 (80,665 acre⋅ft)[1]
Surface elevationBetween 250–368 m (820–1,207 ft)[1]
References[1] Specifications, Elan Valley Visitor Centre

The Elan Valley Reservoirs (Welsh: Cronfeydd Cwm Elan) are a chain of man-made lakes created from damming the Elan and Claerwen rivers within the Elan Valley in Mid Wales. The reservoirs, which were built by the Birmingham Corporation Water Department, provide clean drinking water for Birmingham in the West Midlands of England. The five lakes are known as the Claerwen, Craig-goch, Pen-y-garreg, Garreg-ddu, and Caban-coch.[2]

Water from the reservoirs is carried by gravity to Frankley Reservoir in Birmingham via the Elan aqueduct. Pumping is not required because the network drops 52 metres (171 ft) along its 73-mile (117 km) length from its source to Frankley. A gradient of 1:2,300 maintains a flow of less than 2 miles per hour (3.2 km/h); water takes one and a half to two days to reach Birmingham.[3] The aqueduct, which was started in 1896 and opened in 1906, crosses several valleys and features numerous brick tunnels, pipelines, and valve houses.[4]

Work to build the Elan Valley reservoirs was undertaken because the rapid growth of the industrial city of Birmingham in the late 19th century had led to a lack of available clean water. Numerous outbreaks of disease prompted Birmingham City Council to petition the British government which passed the Birmingham Corporation Water Act in 1892.[5] It allowed the corporation to acquire by compulsory purchase all the land within the water catchment area of the Elan Valleys. Thousands of navvies (workers) and their families lived in the purpose-built Elan Village during the construction of the first four dams at the turn of the 20th century. In 1952, the Claerwen dam was opened by Elizabeth II in one of her first official engagements as monarch.

Drinking water from the Elan Valley is noted for being exceptionally soft, contrasting with water from local supplies in the West Midlands, not served by the Elan aqueduct, which are noted for hardness.[6]

The reservoirs are now owned and managed by Dŵr Cymru Welsh Water. The water filtration works further down the valley is run by Severn Trent Water.

  1. ^ a b c d e f g "Specifications". Elan Valley Visitor Centre. Archived from the original on 20 February 2013. Retrieved 12 November 2012.
  2. ^ "Powys Digital History Project: Elan Valley Reservoirs". Retrieved 9 May 2012.
  3. ^ "Powys Digital History Project: Elan Valley Dams". Retrieved 9 May 2012.
  4. ^ "Valve house hidden in the woods". geograph.org.uk. Retrieved 12 November 2012.
  5. ^ 55 & 56 Vict. c. clxxiii
  6. ^ "How do I know if the hardness of my water is detrimental to my plumbing?". Aqua-Nouveau. 2009. Retrieved 5 February 2009.