1. 30m length x 6m high x 6m wide. Single span round arch & traverses Nant y Haydd. Orientation E-W.(RSJ 2000).
2. Part of the Elan Aqueduct (nprn 95469), itself part of the Elan Valley Water Scheme (nprn 96459), the Elan Conduit continues the route near Elan Village. It consists of Filter Beds (nprn 32524), Nant Madog Aqueduct (nprn 261743), Nant yr Haidd Aqueduct (nprn 261740) and a Washout Chamber (nprn 309607).
Small aqueduct carrying the Elan Aqueduct over the Nant yr Haidd.
B.A.Malaws, 03 December 2003.