The Elan Valley Reservoirs are a chain of man-made lakes and reservoirs in the Elan ValleyinPowys, Mid Wales (also known as the "Welsh Lake District"), using the rivers Elan and Claerwen. The reservoirs are Claerwen, Craig Goch, Pen-y-Garreg, Garreg Ddu, and Caban Coch.[1],
The work carried out over a hundred years ago to build the Elan Valley dams and reservoirs was only part of the huge undertaking. Almost as impressive was the challenge of delivering the enormous quantities of water by gravity alone, across very hilly country and over many river valleys, to the new Frankley Reservoir on the outskirts of Birmingham in the West MidlandsofEngland. This involved building the 73 mile long Elan aqueduct[2], down which the water travels at less than 2 miles per hour, taking one and a half days to get to Birmingham.
The Elan aqueduct drops only 52m over a length of 118 km – a gradient of 1:2300. It runs from the Elan Valley to Frankley in Birmingham. There are several signs of the aqueduct between these points, in the form of brick aqueducts, exposed pipelines and red brick valve houses on hillsides.[3]
Birmingham's tap water is noted for being exceptionally soft, with a low percentage of dissolved minerals,[4] as compared to the surrounding areas of the West Midlands not served by the Elan aqueduct, and which have hard water.
There are four main dams and reservoirs (constructed 1893–1904 in Elan Valley, and 1946–1952 at Claerwen) with a potential total capacity of nearly 100,000 megalitres.[2] The dams and reservoirs are:
In addition to the four main dams, there are three other dams at the site:
The Elan Dam scheme was developed in the 19th century following rapid growth of the population of BirminghaminEngland due to the Industrial Revolution. The city's expansion resulted in numerous outbreaks of water-borne diseases; major epidemics such as typhoid, cholera and dysentry regularly broke out because of the lack of clean water. Victorian politician, Joseph Chamberlain, the leader of Birmingham City Council began a campaign to get clean water from the Elan and Claerwen Valley in mid Wales. The area, which had been identified by civil engineer James Mansergh, would be ideal for water reservoirs because:
In 1892, the British government passed the Birmingham Corporation Water Act which allowed the council to compulsory purchase the total water catchment area of the Elan and Claerwen Valleys (approximately 180 square kilometres (69 sq mi). The Act gave Birmingham the powers to move more than a 100 people living in the Elan Valley. All the buildings were demolished; these included three manor houses (two of which had been homes of the English Romantic poet, Percy Bysshe Shelley in 1812)[5], 18 farms, a school and a church (which was replaced with Nantgwyllt Church). Only landowners were given compensation.
Work began to construct the reservoirs the following year in 1893. The Elan Valley Railway was built to all dam sites from a junction of the Mid Wales Railway, at Rhayader. Branches of the standard gauge railway were also built along the dams themselves at varying heights, on wooden scaffolding supported by concrete parapets. The line went as far as the never-completed Dolymynach dam (lower down the valley from the later Claerwen dam). It was built concurrently with the Elan dams because the Caban Coch reservoir would have flooded the construction site of the Dolymynach when it filled up. The railway to Claerwen was subsequently not needed for its construction. Only road transport was used when the Claerwen dam was built more than 45 years later.
Engineer James Mansergh oversaw the project on behalf of the City of Birmingham's Water Department. Due to the height about sea level of the Elan Valley, he used a gravity feed with a gradient of 1 in 2,300 to get the water along a 116 kilometres (72 mi) pipeline to Birmingham.[6] Construction of the dams in the lower Elan Valley would begin first, then work would start on the Claerwen later.
During the 10 year project, the navvies (workers) lived in a village of wooden huts near the site. This settlement, which was strictly controlled to keep order and health, would eventually become Elan Village (see Elan Valley). Guards controlled access in and out; this was done to reduce illness and to stop liquor smuggling. All new workers were deloused and examined for infectious diseases before being admitted. To keep order, a man and his wife shared a terrace house with eight single men. A school was provided for under 11s; although after this they were expected to work. The camp also had a hospital for injuries, an isolation hospital for infectious cases, and a bath house. Men were allowed to drink beer at a pub (however women could not). Other facilities included a library, public hall, shop and canteen. The camp also had electric street lighting which was powered by hydroelectric generators. In 1904, with the construction of the dams complete, most of the navvies moved on to the project to build the Derwent DamsinDerbyshire.
The project to supply water to Birmingham was officially opened by King Edward VII and Queen Alexandra on 21 July 1904.
They played an important role in World War II when the 35 foot (11 m) high Nant-y-Gro dam was used by Barnes Wallis to test his idea of detonating explosives against a dam wall in order to breach it. These experiments culminated in the Dambusters breaching of the dams in the Ruhr Valley. The remains of the breached Nant-y-Gro dam can still be seen today in the same state as it was left in 1942. The dam is now partially obscured by trees, but its location is marked by an interpretative plaque. The Derwent Dam was also used by the Dambusters for practice, though it was not breached.
After the Dambuster Raid steel cables were placed across Caban Coch reservoir to prevent enemy seaplanes landing on the lake.
In the early 1970s it was proposed that the Craig Goch reservoir should be substantially increased in size with a new and higher downstream dam together with another dam to the north-west, impounding water that would otherwise have flowed down the Ystwyth valley. This scheme would have created a huge reservoir dwarfing all others in Mid Wales, and flooding miles of wild upland valleys. The proposals were eventually abandoned in the face of reducing projections for industrial water demand and an increasing awareness of the environmental issues that such an expansion might create.
The reservoirs are now owned by Dŵr Cymru Welsh Water, although the filtration works further down the valley is run by Severn Trent Water.
A scale model of the reservoir network, in the form of ornamental ponds, is in Cannon Hill Park in Birmingham.
 |
This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. Please help improve this article by introducing more precise citations. (April 2009) (Learn how and when to remove this message)
|
52°16′20″N 3°41′20″W / 52.27222°N 3.68889°W / 52.27222; -3.68889
