Water Conduit

The Department's description

Exterior description and setting

The water supply from the Mournes to Belfast is carried across a minor stream in a closed riveted sheet steel conduit 1.5m wide by 1.8m high. Its designed capacity is 620 million litres of water per day, the same as the cut-and-cover sections of the conduit (of 1.7m square cross section). The aqueduct is supported on abutments set 4.1m apart at the top and battered outwards towards the bottom. Their walls are faced with strap-pointed dressed granite blocks set in regular courses, the tops of which are coped in concrete. Steps, also of concrete, cut through the abutments to the top of the conduit to facilitate access across the stream; galvanised steel handrails have been installed along the top of the conduit in the recent past.

The structure is set in a demarcated area. The boundary fence is generally of wire with vertical cast-iron posts, the rounded heads of which carry the initials 'BWC' (=Belfast Water Commissioners). Where the boundary crosses the steam, which is pitched with stones hereabouts, the fence is of wrought-iron chain. There are wrought-iron entrance gates to two opposite sides.

Historical information

The Mourne Scheme, whereby reservoirs in the Kilkeel and Annalong River valleys would supply Belfast with water was first conceived in 1891 by Luke Macassey, consulting engineer to the Belfast City & District Water Commissioners. The passing of the Belfast Water Act in 1893 enabled the first phase of the scheme to commence. This entailed placing intercepting weirs across both rivers to divert some of the water into a conduit which discharged into a service reservoir at Knockbreckan (on the southern outskirts of Belfast) some 35 miles distant from Dunnywater (in the Annalong valley). The conduit was constructed by Messrs Fisher and Le Fanu and opened in 1901. The supply was substantially increased with the opening of the Silent Valley in the upper reaches of the Kilkeel River in 1933. However, because of the size of this particular trough, no modifications to it were necessary. The original contractor's drawing shows the abutments to be of mass concrete faced with stone.

Primary sources:
1. Original drawing of the tunnel and weir in DOE Water Service, Westland House, Old Westland Rd, Belfast – drawing 3A24.

Secondary Sources:
1. Belfast & District Water Commissioners, ‘The Mourne Scheme: development of the Silent Valley and Annalong Valley catchments’ (Belfast, 1959), p.16.

Criteria for listing: architectural interest

F. Structural System
K. Group value

Criteria for listing: historic interest

Z. Rarity
V. Authorship

Evaluation

There is a similar conduit across a minor stream in Moneydorragh More townland (grid J 345214) but this example has arguably the better setting in a secluded woodland glade. This conduit formed part of the first phase of the Mourne Scheme, and because of its group value is therefore of historical value in a regional context. It is also a relatively scarce type of structure, most aqueducts of this type now being piped rather than troughed.