The Claerwen reservoir and dam in Powys, Wales, were the last additions to the Elan Valley Reservoirs system built to provide water for the increasingly demanding city of Birmingham. [1]
The construction of the Claerwen dam, instead of the three dams originally proposed, was commenced in 1946 and completed in 1952. The water impounded formed a reservoir about 4 miles long with a capacity of 10,625 million gallons. Approximately 9.5 miles of road were also provided as access up the Claerwen Valley.[2]