Dam, valve tower, bridge and outflow on Pontsticill Reservoir

The structure consists of a dam, valve tower, bridge, and outflow located on Pontsticill Reservoir. The long dam features a clay core and earth bund construction, with a pitched stone revetment on the inner face of the embankment and a full-length stone wall above it. The inner face of the sloping earth bank is complemented by a low stone wall that supports the roadway above.

The valve tower is constructed from rock-faced coursed stone and topped with a copper-sheet spire, designed in a Gothic style. This octagonal tower rises from the water on an octagonal base. The lower masonry is corbelled out on stepped corbels, with pointed arches between them. It has a moulded plinth, and the base steps forward on the west side for the piers of a porch that leads to a square-headed door, which features a renewed gabled timber hood. Narrow lancet windows are present on the other sides, adorned with stone voussoirs and hoodmoulds, and the tower has stepped eaves. The tall octagonal roof, which has two pitches, is clad in copper sheet and topped with an iron vane.

The bridge extends from the west side of the reservoir to an abutment in front of the door of the valve tower, supported by a single stone pier with blockwork above. The bridge is of lattice steel construction, and the abutment on the land end has walls made of rock-faced stone. Below the bridge, the outflow is designed as a large convex-sided funnel in the reservoir, featuring concrete ribs and a lining of brick or stone.