TRIP TO NORTH WALES| ELAN VALLEY|SNOWDONIA

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.
The Elan dam scheme was developed in the 19th century following rapid growth of the population of Birmingham in England due to the Industrial Revolution. The city's expansion resulted in regular outbreaks of water-borne diseases and major epidemics such as typhoid, cholera and dysentery 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 valleys in mid Wales. The area, which had been identified by civil engineer James Mansergh, would be ideal for water reservoirs because:
it had an average annual rainfall of 1,830 millimetres (72 in).
dams could be easily built in the narrow valleys.
the bedrock was impermeable to water.
there was no need for pumping stations because the reservoirs in Wales would be 52 metres (171 ft) above the water cisterns in Birmingham.
In 1892, Parliament passed the Birmingham Corporation Water Act allowing the Corporation to effect compulsory purchase of the total water catchment area of the Elan and Claerwen valleys (approximately 180 square kilometres (69 sq mi). The Act also gave Birmingham Corporation powers to move more than 100 people living in the Elan Valley. All the buildings were demolished; these included three manor houses (two of which had links with the English Romantic poet Percy Bysshe Shelley in 1812), 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. Construction was overseen by James Mansergh, on behalf of the City of Birmingham's Water Department. Due to the height above sea level of the Elan Valley, water would be fed to Birmingham along a 116 kilometres (72 mi) pipeline that employed a gravity feed with a gradient of 1 in 2,300. The schedule for the project was to build the four lower Elan Valley dams first. The Claerwen would then be built later (work was expected to begin 1939 but was delayed by the Second World War; it was completed in 1952).