Historic Building Details

HB Ref No:
HB18/14/035

Address :
Instrument Sighting Tower Donard Forest Drinnahilly Newcastle Co Down

Townland:
Donard

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Survey 2:
B1

Date of Listing:
07/03/2018 00:00:00

Date of De-listing:

Current Use:
Water Works Structures

Former Use
Water Works Structures

Conservation Area:
No

Industrial Archaeology:
Yes

Vernacular:
No

Thatched:
No

Monument:
No

Derelict:
No

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OS Map No:
255/14NE

IG Ref:
J3616 3018

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Owner Category

Local Govt

Exterior Description And Setting

Situated just inside the tree line a short distance south-west of Drinnahilly summit and on line of the Mourne conduit which is here tunneled under the mountainside. A tower 4.95m square at base and c10m high comprising four slightly tapering walls of random Silurian rubble, with squared granite rubble quoins and concrete coping at top, all now heavily repointed in cement. Entrance at west end of south wall, now infilled with concrete blocks. Single opening on left side of west wall towards top, and another higher up on north wall. Both have single granite heads, no cills, and retain wooden frames; may have originally been shuttered rather than glazed. Although no access was gained, inspection through upper window indicated a square tapering random rubble pillar at centre (the drawing - referred to in the history - shows that it rises from the ground) surmounted by a concrete pillar which projects c.1m above the wall line of the building. This would probably have supported a telescope mounted on a horizontal axis and capable of being turned in a vertical plane. A hemispherical metal frame with eight curved legs rises over this pillar from the wall head; this may have been for protecting the sighting instrument, but there is no indication of how it was covered. The legs of the frame meet at the top in a circular ring which formerly stablised a projecting semaphore pole.

Architects

Not Known

Historical Information

The construction of this section of the Mourne Conduit, which brought water to Belfast from the Annalong and Kilkeel rivers, was advertised by the Belfast City & District Water Commissioners in March 1896. The contract (no.6) was awarded to H & J Martin, Belfast, and involved the construction of a 3445m long concrete-lined tunnel under Millstone and Thomas Mountains, on the north-eastern slopes of Slieve Donard. The aligning of the tunnel necessitated the erection of an instrument sighting tower at each end of its intended route - one here at the Tullybranigan end (at the highest point on the surface and 178m over the tunnel), and another on Millstone Mountain (of which no trace survives). There was also a third near the main road at the Ballagh end, from which sightings were taken into the tunnel as it was being constructed. A contractor's drawing shows a sighting instrument mounted on a metal plate on top of the concrete pillar, all of which was protected by a glazed wooden frame. The tunnel was completed during the summer of 1901 and water flowed to the service reservoir at Knockbracken in October of the same year. Sources : (Advertisement regarding construction of tunnel in PRONI - WAT1/3F/1/1 (March Evening Telegraph, 20 Jan 1900 (shows cross section of tunnel and location of sighting towers; copy of cutting held in PRONI - WAT1/3F/3/2, p.89). Macassey (1901),' 'Mourne scheme and sundry works progress report, 15 1901' (PRONI - WAT1/3CG/6). DDOE Water Service, Westland House: drawing 3B41. LJNew Civil Engineering, 7 April 1988 (article on a similar tower built in connection with Edinburgh water supply).

Criteria for Listing

Architectural Interest

D. Plan Form E. Spatial Organisation F. Structural System J. Setting K. Group value

Historic Interest

Y. Social, Cultural or Economic Importance R. Age S. Authenticity T. Historic Importance U. Historic Associations W. Northern Ireland/International Interest Z. Rarity

Evaluation

This structure was surveyed as part of the Mourne Water Scheme Thematic Survey 1997-2005. There were a number of small concrete object sighting pillars erected in connection with this section of the Mourne Conduit and the Brackenagh Tunnel (eg. HB 16/2/041). This is slightly different in that it is an observatory tower and is much more substantial in terms of its size and design - a tall pillar surrounded by curtain wall. It has an attested historical association with the Mourne Scheme and is probably a unique survival in N. Ireland.

General Comments

Date of Survey

16 November 1999