2002:1021 - KILKENNY: Mill Island and Green’s Bridge Weir, Kilkenny

A second and final season of excavation took place between April and July 2002 at an industrial watermill site and associated stone weir, known as Mill Island and Green’s Bridge Weir. The site is on the River Nore, immediately downstream of Green’s Bridge, in Kilkenny city. After initial assessment in 2000, full excavation began in 2001 but had to be suspended owing to rising water levels (Excavations 2000, 544, 00E0390; Excavations 2001, No. 708). Work forms part of the wider pre-development mitigation for the Kilkenny Flood-Relief Scheme, which proposes the complete removal of Mill Island and the remodelling and lowering of Green’s Bridge weir.

Excavation revealed seven phases of construction, use and modification, followed by modern dereliction and destruction. The site was divided into six major elements: Area 1: Green’s Bridge weir, eastern arm; Area 2: Green’s Bridge weir, western arm; Area 3: mill buildings forming the northern part of Mill Island; Area 4: a long strip of land to the south of the mill buildings; Area 5: the extreme southern tip of Mill Island; and Area 6: a water-wheel pit, immediately to the east of the mill buildings.

Phase 1 (undated) was represented by the truncated foundations of a rectangular drystone mill (Area 3), measuring 6.5m north–south by 3m. The foundations consisted of riverbank clays enclosed on all sides by drystone walls faced on one side only and resting directly on river gravels. An adjacent mill-stream was also cut through the left (east) riverbank, resulting in the creation of an island (later known as Mill Island). The water-wheel pit (Area 6) within the mill stream was lined with tight-fitting limestone slabs. This phase is probably that referred to as a ‘Corn Mill’, with stone walls and slate roof, in the Civil Survey of 1654.

Phase 2 (1625–1758) was represented by construction of a southern machine room onto the Phase 1 mill building (Area 3) and a masonry and timber half-weir, or ‘deflection dam’, to the north (Area 1). The machine room was 4.85m long and 3.6m wide (maximum) and was built of random-rubble stone on a wattle revetment fence, along the riverside (west) face. The deflection dam was 26m long (minimum) and was built in two sections. A mortared limestone rubble masonry section joined the northern mill building, revetted on the south-western side with wattle. This continued into the river as a timber ‘beaver dam’, represented by longitudinal elm logs and reused, worked oak timber pegged by a row of 34 vertical oak and alder stakes. The dam extended into the left river channel at an angle of 25º but did not span the river. Both wattle panels were radiocarbon dated to 40±50 BP, 270±50 BP, 260±50 BP, 310±50 BP (GU-10470–3), giving a date range overlap between 1670 and 1680, which dates the construction of both the southern room and the dam. The remains of a sluice-gate were also revealed within the water-wheel pit (Area 6), which were relined with tightly fitted blocks of black ‘Kilkenny Marble’. A lead cloth seal possibly dating to the 17th century was recovered from the construction levels of this phase. This phase appears on Rocque’s 1758 map of Kilkenny, which also shows a water-wheel adjacent to the southern mill building.

Phase 3 (1758–63) constituted the further extension of the mill building (Area 3, Room A) by 2m into the river and the reinforcement of the north mill wall. The slight remains of a cobbled surface were identified in this phase, and the mill continued to use the composite masonry-and-timber deflection dam to the north, although slight modification was made to its upper surface. This phase pre-dated the truncation of Phase 4.

Phase 4 (1763–97) followed the massive flood damage caused by the Great Flood of 1763 and the subsequent repairs. Damage to the mill included the total destruction of the north-western corner of the building (Area 3, Room A). The interior floor surface was completely washed away, and the mill was filled with alluvial sand and debris. The flood also resulted in the deposition of up to 2.5m of sand to the south of the mill building, extending and raising the central and southern part of the island (Area 4). In this phase the western river wall, the north-west corner and the northern wall of the mill were all rebuilt and reinforced. No evidence of a replacement floor surface was uncovered.

Phase 5 (1797–1841) was the most extensive rebuilding and remodelling episode of the mill and the weir and is shown on the first-edition OS map. The full length of Mill Island, 66.5m long and 5.5m wide (Area 4), was fully revetted in stone up to the mill buildings. A second room (Room B), 5.7m long, was constructed immediately south of Room A, and a fine cobbled floor was laid across both rooms. This floor was dated to after 1797 by a silver pendant. A corn-drying room (Room D) was also built south of Room B. During this phase the water-wheel was moved to the north, with a 3.2m-long stone-lined water-wheel pit cut into the north-eastern corner of Room A. To the north, the dam was completely rebuilt as a stone weir (Areas 1 and 2), with an earthen rubble core and capped with drystone pitching stone. The new V-shaped weir spanned the river channel, with a bull nose to the north diverting water to mills on both banks of the river. This weir contained a disused late 18th-century French burrstone, a timber plank dated to AD 1125±9 (Q10220) and brick rubble.

Phase 6 (1841–72) concerned minor alterations to the northern and southern ends of the island (Areas 3 and 5), shown on the 1872 OS revision. Up to 4m of accumulated alluvial sand in Area 5 was revetted with poorly mortared, random-rubble walls. A triangular structure was constructed to the north of Room A, directly onto the weir, to take the footings of a wooden footbridge and stairs to the first floor.

Phase 7 (1872–1900) was the remodelling of internal features in Area 3 and the water-wheel pit (Area 6) and the possible conversion to a tuck mill. The wheel pit (in Room A) was remodelled, creating a smaller pit, 1.6m wide. A hard-packed floor surface and a dividing wall were inserted between Rooms A and B. A red-brick fireplace was inserted in Room A, and a deep pit was cut in Room B. Room C was built enclosing the space between Rooms B and D, with a new kiln. The water-wheel pit lining was replaced with large limestone slabs, and a central axle pier was constructed, or reconstructed. The east wall of Room A/Area 3 was also partially reconstructed in ashlar, and a stone sluice-gate slot was inserted. The central area of the island (Area 4) was marked as a ‘tenters’ area on the 1872 OS map, indicating wool manufacture in the vicinity.

During the early 20th century, up to the 1940s, Green’s Bridge Mills was being utilised to generate electricity. Room B continued to be used as a fuel store, although the buildings on Mill Island were ruinous by the time of the 1946 revision of the OS and derelict by 1953. The final levelling of the remainder of Green’s Bridge Mills occurred in the 1980s during the creation of a public amenity (the ‘Peace Park’) and many associated features.

Much of the material evidence from Mill Island indicated that corn some milling was being undertaken, although sources also point to tucking in this and the adjacent mill buildings. Red-brick kilns were used to dry grain before grinding, and a number of local and imported millstones, pivot stones and corn-milling machinery were recovered from the archaeological levels of this site. Other artefacts recovered included reused Tudor stone, glass, pottery, clay pipes and a number of small metal domestic pieces.

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