Nant-y-Gro Dam

Nant y Gro Dam, located upstream of Caban Coch Dam, was initially built to create a one-million-gallon reservoir supplying up to 45,000 gallons of water daily to the navvies village during the construction of the Elan Valley dams.

Abandoned after the completion of the Elan Valley water scheme, the 35-foot-high dam was later used for secret World War II experiments by Barnes Wallis, inventor of the Bouncing Bomb. In May 1942, 62lbs of TNT cracked joints and detached part of the spillway. A later test in July 1942 used a 280lb charge, breaching the dam 60 feet wide and 24 feet deep, aiding the development of the bouncing bomb. This culminated in the successful Dambusters Raid on May 16, 1943.

The site is accessible today via a footpath from Caban Coch Dam, opposite the visitor centre. Remnants such as a concrete storage tank and cast iron pipes are still visible today.

Do you have more information about this location? Inform us!

Source

• Text: TracesofWar
• Photos: Bill Nicholls