Elan Valley Reservoirs
The Elan Valley Reservoirs are a chain of man-made lakes in Wales, west of Rhayader, (also known as the "Welsh Lake District"), using the rivers Elan and Claerwen. The reservoirs are Claerwen, Craig Goch, Pen-y-Gareg, Careg-ddu, and Caban Coch.
Description
The reservoirs were constructed early in the 20th century to supply clean water to the Birmingham area, by gravity feed along an aqueduct with a gradient of 1 in 2,300. Before the construction of the dams, the Elan Valley Railway was built to all dam sites, from a junction at Rhayader. The railway was also built along the dams themselves at varying heights, on wooden scaffolding supported by concrete parapets. The railway itself went as far as a never completed Dolymynach dam lower down the valley from the Claerwen dam, as it had to be built at the same time as the other dams as the lake would have flooded the construction otherwise, however, it was never needed, and the Claerwen dam used road transport only, being opened in 1952.
The navvies lived in a village constructed from wooden huts. This later became the permanent Elan Village (designed as a Model Village by the Birmingham Arts & Crafts Architect Herbert Tudor Buckland, the original settlement had a guard to prevent the illegal importing of liquor.
They played an important role in World War II when the 35 ft. 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.
In the 1970's it was proposed that the Craig Goch reservoir should be substantially increased in size with a new and higher down-stream dam together with an upstream dam to contain water that would otherwise have flowed down the Ystwyth valley. The proposals were eventually abandoned in the face of reducing projections for industrial water demand and an increasing awareness of the environmental problems that such an expansion might create.
When construction of the dams was complete, most of the Elan Valley "navvies" (construction workers) moved on to the Derwent Valley in Derbyshire. The Derwent Dam was also used by the Dambusters for practice, though it was not breached.
The reservoirs are now owned by Dŵr Cymru Welsh Water.
A scale model of the reservoir network, in the form of ornamental ponds, is in Cannon Hill Park in Birmingham.
