Cassy Water Bridge, Near 381 Killowen Road, Killowen, rostrevor, Newry, Co Down, BT34 4SF

This twin-arch granite bridge carries the Kilkeel – Rostrevor road over the Cassy Water, near Killowen. It is considered to be of a high standard and was likely constructed between 1880 and 1899, replacing an earlier structure. A bridge is marked at this location on an Ordnance Survey map from 1834, and an 1836 Ordnance Survey Memoir describes a previous “plain rough structure” with longer parapets. The 1862 Ordnance Survey map refers to the bridge as Causeway Water Bridge and shows three cutwaters, suggesting a different arrangement than the current structure.

The bridge has two arches of equal size, both skewed and embellished with rusticated voussoirs. Only the western arch is currently in use. The soffit stones are of squared rubble and are set at a skew, rather than orthogonally, a feature more commonly found in brick construction. The abutments and pier are built of regularly coursed, roughly dressed granite blocks. Each side features a rounded cutwater, rising to a shallow dome at arch spring level. The spandrels and parapets are of squared rubble, the latter coped with large blocks. The approach walls on either side are of random rubble. A slight hump exists on the road surface, and a footpath runs along the downstream side. The bridge’s total width is 8.9 metres, including 0.45-metre-thick parapets; there is no indication of any widening.

The bed of the river is paved with granite, creating four shallow steps immediately downstream of the bridge. The three upper steps are faced with cement-rendered rubble, while the bottom step comprises large, squared blocks. This design was intended to minimise river scouring and slow floodwater passing through the arches. The bridge is of industrial archaeological interest and possesses local historical interest. The listing encompasses the bridge and the granite steps in the riverbed.