The dams of the Elan Valley

How the reservoirs were built

An Act of Parliament was passed in 1892 for Birmingham Corporation to compulsorily purchase the water catchment area of the Elan and Claerwen Valleys.

In 1893 the building work began. Around 100 occupants of the Elan Valley had to move, though only the landowners received compensation payments. Many buildings were demolished, including 3 manor houses, 18 farms, a school and a church. Six reservoirs were planned: Caban Coch, Pen y Garreg and Craig Goch in the Elan Valley, and Dol-y-Mynach, Cil Oerwynt and Pant-y-Beddau in the Claerwen Valley.

The first phase included Caban Coch, Garreg Ddu, Pen y Garreg and Craig Goch dams, along with the foundations of Dol y Mynach Dam, Dol y Mynach Tunnel, and the 73-mile aqueduct to Frankley Reservoir near Birmingham. These were completed by 1904. On 21st July 1904, King Edward VII and Queen Alexandra opened the Elan dams, and water began flowing to Birmingham.

The second phase was delayed by the First and Second World Wars, and work did not restart until 1946. With advances in engineering, only one large dam, Claerwen Dam, was needed instead of three smaller dams in the Claerwen Valley. Claerwen Dam was opened by Queen Elizabeth on 23rd October 1952.