Compensation Basin at Pontsticill Water Treatment Works

The Compensation Basin at Pontsticill Water Treatment Works is a notable structure that includes the portal of a tunnel, the walls, piers, and steps of a curved basin, as well as a weir. The tunnel is lined with brick, while the portal features large blocks of coursed rock-faced stone, massive granite voussoirs with diamond ends, a keystone, and a frieze of dentil moulding. Flanking piers rise to a cornice made of giant blocks, which contains a pedimented surround for a bronze plaque. On either side, walls of coursed rock-faced stone border the basin, and flights of steps with giant rock-faced coping lead down to the water level in front of the portal. The weir, which includes four sluices with piers on each side, marks the end of the basin and the return to the river.