A dam that formed a small reservoir north of the Brynyrafr and South Cambrian lead mine complexes and may have supplied water to either one or both mines. The reservoir and dam are shown on the 1891 Ordnance Survey map. When the site was visited during Upland Survey in 2005, the dam was relatively intact, although broken in the middle. The dam was 25m long west northwest-east southeast and stood up to 2m high. An overspill channel at the eastern end of the dam was 2m wide. J.J. Hall, Trysor, 3 January 2006