2013:348 - Demesne, Rathlin Island, Antrim

As part of an ongoing programme to upgrade the waste-water, mains and sewerage system, Northern Ireland Water Ltd proposed to construct waste-water treatment works (WwTW), pumping station and associated pipe work in Demesne townland on Rathlin Island, County Antrim.

The proposed development site is situated in an area of improved pasture to the south of Church Bay in Demesne townland on the west coast of the southern arm of Rathlin Island. The WwTW and the majority of the pipe leading to the pumping station will be situated in a single field on the east side of a minor road leading from the harbour in Church Bay to Rue Point at the southern tip of the island. The proposed pumping station will be constructed on the shoreline on the west side of the minor road. Rathlin Island has been designated an area of outstanding natural beauty (AONB) and is part of the Antrim Coast and Glens AONB. The Rathlin Island Coast was declared an Area of Special Scientific Interest in September 1991 (ASSI 033).

Three sites (ANT001-014, ANT001-044 and ANT001-094) lie within a designated scheduled area to the north of the proposed development site and a Bronze Age cist (ANT001-015) was discovered at the north end of the field in which the proposed WwTW and pipelines will be constructed. Given the potential for further cist burials and the possibility of recovering Mesolithic material along the shoreline it was agreed that pre-constructing testing should be carried out. The main area of disturbance was at the site of the new WwTW and this area was tested on 28 March 2013.

The dark-brown topsoil was removed from an area measuring 21m north-west/south-east by 13m to reveal a mixed layer of topsoil and the underlying raised beach material consisting of rolled pebbles and small stones in a matrix of gritty cream sand. A 2.1m-deep trial pit excavated in the area of the tank closest to the field wall showed that this overlaid a succession of sand deposits 1.39m thick with a layer of medium-sized to large stones at its base. This stone layer lay at the interface of the succession of sand deposits and the underlying layer of heavy, very compact red glacial till (boulder clay).

The monitoring of the open cut trench for the interconnecting pipework was carried out from 2-10 May 2013. The stratigraphy in the pipe trench, not unsurprisingly, was the same as that encountered during testing. The monitoring of the open cut trench for the new water main pipe was carried out on 22 May 2013. Once again the stratigraphy in the pipe trench was the same as that encountered during testing and monitoring.

No archaeological remains were uncovered during the course of the investigations and it was obvious that the ground within the test area had been previously undisturbed.

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