Dam at the Upper Neuadd Reservoir

The dam at the Upper Neuadd Reservoir is a Grade II* listed structure built with massive rock-faced squared blocks that have tooled edges. It features a long, straight design with a sloping face and a quarter-round moulded stone coping. The central spillway is flanked by two towers. A walkway bridges the spillway, supported by seven stone piers that rise from the sloping face of the high rock-faced main dam, which curves out at the base to create a gentler slope.

The western tower is significantly larger and has a square plan, featuring banded rusticated angle piers and a modillion cornice that is broken forward around the piers. Tapered square finials sit at each corner, surrounding a stone spire. The south front of this tower includes a large three-light mullioned window with an arched head, stone voussoirs, sandstone mullions, and massive cast-iron glazing bars. The western and eastern sides have low doors that are protected by stone balconies on the south side.

The smaller western tower is a square neo-classical building that shares the same banded rusticated angle piers and modillion cornice, but it has a heavy blocking course above its south gable. It features a low south lunette window with stone voussoirs and cast-iron glazing bars, along with doors on each side that also have stone balconies on the south.

On the eastern side of the dam, below the main tower, there is a grand tunnel outlet designed in a Piranesi style. This outlet features a large arch framed in massive rustication, with a tapered western side and a corbelled parapet topped with a low central gable that holds a bronze plaque commemorating the completion of the dam in 1902. The tunnel is lined with brick, and a platform in front of the tunnel covers an arched water outlet on the western side.