Height – 56m
Length – 355m
Volume – 48,3000 megalitres
Although the outside of Claerwen (Clear Light), looks like the Elan Valley dams, inside it is a concrete structure. It was built from 1946 – 1952 with a workforce of 470 men. Italian stonemasons worked on the dressing stone, so the dam blends in with the Elan Valley dams as the British stonemasons were working in London after World War II. It was opened by Queen Elizabeth II on the 23rd of October 1952 in her first engagement in Wales.
Claerwen holds nearly as much water as all the other reservoirs combined, and can produce 1680 kilowatts. In total all the dams can produce 3.5 megawatts, which is about 6000 homes.