2001:699 - KILKENNY: NOR-1, Green’s Bridge, Kilkenny

Introduction
An excavation was carried out between August and November 2001 as part of ongoing pre-development assessment for the River Nore (Kilkenny City) Drainage Scheme (formerly known as the Kilkenny Flood Relief Scheme) at NOR-1, Green’s Bridge, Bishopsmeadows/Newpark Lower, Kilkenny. This excavation followed on from land-based assessment carried out in 2000 by the writer (Excavations 2000, No. 544, 00E0390) and underwater assessments of the bridge site by Niall Brady (Excavations 2000, No. 549, 00D033). Proposed development includes the installation of a gabion wall and widening of the left bank of the River Nore by 22.5m.

Background
Green’s Bridge connects north-east Kilkenny to the early medieval ecclesiastical monastery of St Canice’s and the medieval borough of Irishtown. The present bridge is an ornate 18th-century stone replacement of a late medieval stone bridge, destroyed by floods in 1763. This itself probably replaced an earlier bridge on the site of an ancient ford. Early records show Green’s Bridge or ‘the Great Bridge’ to be the only bridge to Kilkenny in 1178. This was destroyed by floods in 1338, with the replacement destroyed again in 1500 and rebuilt in 1526. The site of this bridge is marked on the Urban Archaeological Survey of Kilkenny (Ref. Map 4a: 3) and is faintly visible as a low-water outcrop island within the river channel. The bridge led to the town via Green’s Gate, also marked on the Archaeological Survey (Ref. Map 4a: 40) as a site destroyed above ground level. A medieval mill known as Green Bridge Mill is noted in the Urban Archaeological Survey (Ref. Map 4a: 42), close to (or on) the site of the bridge. This watermill has been associated with a 2.2km-long mill-race, also marked on both Rocque’s map of Kilkenny (1758) and Byron’s map (1787).

Results
Excavation was undertaken as a dryland operation with the use of large water-pumps and the construction of a large coffer-dam in the river to facilitate dry removal of the riverbank edge. Two cuttings were opened (Areas 1 and 2), each presenting different logistical and archaeological difficulties. The total area investigated measured 25m east–west by 19m by 3.5m deep. Excavation revealed five surviving sections of the collapsed 16th-century bridge and the walls of the westernmost extent of a post-medieval mill building with associated riverbank revetment walls.

Area 1
The westernmost feature, Pier 1, was an in situ bridge pier, with ashlar facing on the downstream and western face. This pier had slumped 40° to the west and was 3.4m long (north–south) by 2m wide by 0.8m+ deep. Immediately to the south of this pier was a large section of collapsed masonry, 2.1m long (north–south) and 1.6m wide, lying 1.6m south of the pier. It appeared to be part of the arch of the bridge. Both features lay immediately west of the existing edge of the present riverbank and will therefore be unaffected by further development.

To the east of Pier 1 was a second fragment of masonry, measuring 1.6m (north-west/south-east) by 1.3m by 0.7m deep. This was part of the balustrade wall on the top of the bridge, distinguished by an attached narrow wall fragment. It lay 2.3m east of the river edge and Pier 1, and therefore was removed intact from the development area. Further east was Pier 2, a large fragment of masonry with a dressed-stone underside face, representing a fallen vertical pier. The pier was 2.7m long (east–west), 2–3m wide and 0.8m deep. It was abutted by an area of hard compacted lime mortar, 11.5m long (east–west), 4.75m+ wide and 0.1m thick. This was possibly a construction surface, terminating against Pier 2.

Area 2
A further 6.5m east of Pier 2, in Area 2, was a revetment or abutment structure for the road and bridge, Pier 3. This both lay under and formed part of the mortar surface, and is a unique construction of timber piles along the riverside face (1m long, 0.15m in diameter), supporting a limestone flag plinth (0.1m thick) with organic matting, sitting directly on the original clay bank. This was sealed by a capping of hydraulic lime cement (0.25m thick), containing a two-part framework of squared and jointed oak timbers (possibly a reused timber screen from a medieval house), acting as reinforcement. Pier 3 was 6.3m+ long (north–south) by 2.1–2.4m wide and 1m+ deep.

Pier 3 was abutted by a wall orientated diagonally to the river and acting as a partial cut-water, post-dating the demolition of the bridge. This adjoined a rectangular stone building orientated east–west and measuring 3.2m+ in length (east–west) by 3.5m in width, extending east into the baulk. The building consisted of two parallel walls, 0.45m thick and 1.85m high, extending west to a rough semicircular drystone river revetment wall, the latter tying in to the cut-water wall, which would have protected the mill building. The walls extended east into the baulk and form part of a late post-medieval phase of the mill, straddling the mill-race 13m to the east and marked on Rocque’s map of 1758.

The walls of this mill stratigraphically post-date the 1763 destruction of the bridge and were also dated by a coin found under the foundations to the early 18th century. However, it remains possible that the recorded earlier medieval mill building was destroyed along with the bridge.

Conclusions
Excavation of this site revealed a number of important medieval features associated with the Great Bridge of Kilkenny and probably dating from the 1526 rebuilding of the bridge. Mitigation of the proposed development included the removal of a complete section of collapsed masonry, realignment of the western limit of left-bank bulk excavation and preservation in situ of the surviving bridge piers, which lie immediately below the formation depth of this development. However, it is also hoped that a redesigning of the proposed gabion wall can accommodate the preservation in situ of Pier 3 by use of narrower sheet piling layout, which will avoid the structure altogether. Further mitigation of this development on the right bank will require excavation of a 5m-wide cutting on the right bank, which it was hoped to undertake in May 2001.

2 Killiney View, Albert Road Lower, Glenageary, Co. Dublin