2016:823 - Clooney (Building 17, Gas Main & Pop Up Switchboard - Ebrington Barracks), Derry

Works associated with the gas supply installation comprised the laying of gas supply mains in open trenches measuring approximately 1.1–1.4m deep x 0.29–0.3m wide, the connection to existing pipes, the removal of some existing pipework and the laying of kerbs and paving where necessary. Approximately 600m of new gas mains was laid.

The Gas Main is primarily located outside the southern and eastern portions of the Star Fort and inside the northern limits, crossing the line of the Star Fort wall at north, north-east and south. Sections of ducting associated with the provision of gas to the buildings are located within the Star Fort, primarily within its eastern and northern limits. Generally, the pipe work was laid within the existing roads at the Barracks and the trenches were cut through existing road surfaces, sub-base materials and subsoil. Existing ducting installed during previous infrastructure works at the site was utilised, where possible.

Portions of the Star Fort wall were encountered at four locations during the excavation works associated with this scheme.

No other historical or archaeological features were identified during works associated with the installation of the new gas main with the exception of some truncated red-brick drainage features within the south-east limit of the site, near the Limavady Road.

Works associated with the provision of the pop-up switchboard comprised the laying of electricity supply cables in open trenches measuring 0.6–0.9m deep x 0.3–0.6m wide, the provision of a joint hole measuring 3m x 3m x 0.9m, the provision of new electrical manholes, the construction of a concrete base for the new switchboard and the removal of existing cables and a switchboard.  The scheme also provided for the installation of ducting, in order to minimise sub-surface disturbance should it be necessary to install additional cabling in the future.

No historical or archaeological features were identified during works associated with the installation of the Pop Up Switchboard or its associated cabling/ducting.

Works comprising the treatment and removal of vegetation within the garden enclosed by the Star Fort wall and Building 17 were undertaken under archaeological supervision as the works were located within close proximity to a known Scheduled Monument namely the Star Fort at Ebrington Barracks and partially within the associated Scheduled Area. Works did not include excavation of soil or subsoil material and were undertaken in line with the Scheduled Monuments Consent for the scheme.

Works associated with the provision of three sets of steps included excavation and construction of the steps themselves and installation of a gated entrance affixed to the Star Fort wall. Within the footprint of Steps 1, excavation revealed undisturbed subsoil. Within the footprint of Steps 2, excavation revealed disturbed layers up to 3m deep with considerable quantities of modern construction materials evident, including a large concrete cube/block with lifting shackles attached. No evidence for the former steps which were located in this area were identified during monitoring works.

However, removal of layers of modern infill revealed an old retaining wall c.0.9m high which is likely to have been associated with the former steps. Of random rubble construction with a concrete coping, this feature has been retained as a decorative feature to the immediate north of the new steps, with a new retaining structure c.1.5m to north ensuring the structural integrity of the bank.

Within the footprint of Steps 3, construction depth was achieved within disturbed subsoil.

Additional works included the installation of foul and storm pipes beneath the Star Fort wall to north of Building 40 and west of Building 17: within both of these areas of the site, trenches were excavated both within and without the Star Fort wall to ascertain the depth of the monument and services plans redesigned to facilitate the installation of services beneath the Scheduled Monument, in line with the Scheduled Monuments Consent for the scheme. Excavation for Services at Building 40 revealed that the foundations for the Star Fort wall were 1.25m below the existing surface while at Building 17 the foundations were 1.75m below. In both areas, the new pipes were laid under the Star Fort wall with a Geotextile membrane laid prior to reinstatement.

In addition a series of Test Pits were excavated under archaeological supervision to provide additional information regarding the location and extent of the eastern section of the Star Fort, to assess its survival and provide additional information to facilitate the preparation of a sympathetic design and layout in preparing development proposals within this portion of the site.

Nine pits, generally 3-5m long and c.1.2m wide were excavated within the Scheduled Area with an additional pit excavated as part of the Gas Mains scheme, outside of the Scheduled Area.

Within TP 4, a portion of the Star Fort wall previously identified by Northern Archaeological Consultancy (NAC) and covered with Geotextile was identified at a depth of 0.15m below the existing ground surface.

No archaeological features, remains or deposits were identified within any of the Test Pits in addition to those portions of the Star Fort wall detailed above.

150 Elmvale, Culmore, Derry BT48 8SL.