In the Elan Valley the second dam 'up-river' after Caban-coch doesn't really look like a dam at all. This is Garreg-ddu, which isGarreg-ddu viaduct sometimes called the 'submerged dam'.
Garreg-ddu plays a more important part in providing a constant supply of water to Birmingham than you would guess
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Uploaded: May 15, 2015