Height – 11m
Length – 58m
Nant y Gro was originally used to supply workers in the village with water, but was breached during testing of the charges for the bouncing bomb in 1942. The dam was one fifth of the size of the Möhne dam in the Ruhr valley, one of the targets identified by the British Air Ministry. Barnes Wallis came up with the idea of the bouncing bomb – the bouncing was not tested at Nant y Gro, but the explosives were. Have a look at the video in the exhibition hall for a clip of the tests.
Nant y Gro means Gravelly Stream.