Canvas Print of Water cascading over Craig Goch Dam on a grey autumn day in October. This has to be seen to be believed. Craig Goch Dam is the top dam in the Elan Valley. The Elan Valley is a bit remote and in the county of Powys. It used to be part of Radnorshire until the county boundaries were changed. Because of the dam’s construction you can drive over it to a car parking area and walk from there.