Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 145,004 pages of information and 230,624 images on early companies, their products and the people who designed and built them.
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.