Upper Clydach Aqueduct (Pontardawe A4) has a late 18th century, segmental stone arch, 7.5m span, 1.7m high.
Downstream from the present High Street Bridge Pontardawe Aqueduct is aligned on a north-south axis over the Upper Clydach River,. It has one segmental stone arch of 7.5m span and about 1.7m high and two overflows on its upstream (western) side. The upstream elevation has been partly hidden by later bank revetment walls, but the downstream elevation retains its original shallow flanking buttresses. The downstream squared rubble face of the aqueduct has been much patched with blue and red brick. Part of the parapet has collapsed. Some of the coping stones have been replaced by square blocks of copper-slag and others, more recently, with concrete blocks.

Aqueduct SN 7212 0394

Stephen Hughes, 14.08.2006.