2009:017 - DONEGALL QUAY, BELFAST, Antrim

The archaeological mitigation for this scheme took place over five years intermittently from 2004 to 2009 and consisted of monitoring of engineering test-pits, the excavation of a perimeter trench for sheet piles, and monitoring of ground reduction and excavation of drainage trenches. The site is located within central Belfast, lying on the eastern edge of the zone of archaeological potential, which delimits medieval and 17th-century Belfast. The site is bounded by Corporation Square to the north, Donegall Quay to the west, the Lagan Lookout Visitor Centre to the south and the River Lagan to the east.
Archaeological deposits previously uncovered comprised the remains of the former 18th-century Limekiln Dock and later construction of Donegall Quay, both of which were found to be surviving below modern made ground within the development site of a two-storey underground carpark with a mixed retail, office and hotel development above, at Donegall Quay, Belfast city centre.
The earliest structure uncovered, the remains of the Limekiln Dock, dates to around the late 18th century and was found to be located roughly within the centre of the development area. The dock was constructed of stone and mortar, surviving to a height of 2–4m, located c. 2.5m below modern ground level. An apparent second phase of construction was present in the form of a timber quay which blocked off the slipway into the Limekiln Dock and extended out further into the river, and stretched the entire length of the development site, comprising four individual rows of large, in situ upright timbers. This quay is thought to have been built in late 18th/early 19th century.
Excavation of drainage trenches and other ground disturbance during 2009 uncovered similar stratigraphy to that uncovered during excavation of test-pits and ground reduction in previous years.
The second stage of groundworks and monitoring began on 18 June 2008 and continued intermittently until completion on 26 August 2009.
The full extent of the slipway walls was not uncovered during Phase 1 groundworks due to the then limits of excavation and ground reduction. The proposed drainage works of the second phase of the development extended the site limits west towards Donegall Quay Road and there was a possibility that the works would impact upon or expose the remaining extent of the slipway walls associated with Limekiln Dock. There was also the probability of impact upon further timber piles associated with the dock.
The proposed drainage works for the Obel development consisted of two trenches. The first trench extended from the south-west corner of the development area running north to south for 24m parallel to the Phase 1 site limit and the foundations of the development buildings. This trench ran perpendicular to the slipway walls exposed in the first phase of monitoring.
The stratigraphic make-up of the trenches consisted of a basal layer of glacial clay or ^Belfast sleech’, average 0.15m thick as exposed and at a depth of c. 2m from the modern road surface. This clay was immediately overlain with a band of loose sandy silt, 0.56m thick, with evidence of 19th-and 20th-century red brick fragments. This backfill was in turn immediately overlain with a broken red brick and concrete surface, 0.45m thick, more than likely an earlier road surface, above which was a layer of modern hardcore 0.52m thick immediately overlain with the present modern roadway/cycle path.
Stone square setts associated with the previously uncovered tramway were again found in Drainage Trench 1. The tramlines were laid within these cobbles, and immediately overlain with the modern tarmac road. The cobbles had been laid into a bedding of quarry dust above a 0.2m-thick layer of concrete mix.
The arch of an old red brick Victorian drain was located in the west-facing section of Drainage Trench 1 at a depth of 2.3m from the current road surface.
In the second drainage trench two wooden stakes were recovered from within the silty clay containing red brick rubble and mortar. The wooden stakes measured 0.11m by 0.11m at the top and tapered to at point at the base; they both measured 1.27m long.
The extensive nature of the groundworks required for this development have ensured that the vast majority of the site area has been subject to extensive monitoring and excavation during ground reduction, piling and drainage trenching phases. The groundworks are now complete and the development is fully under way.