Intercepting Weir

The Department's description

Exterior description and setting

Know as the Annalong Weir, this structure diverts water from the Annalong River into the Mourne Conduit. It comprises a sloping masonry apron with steel weir plate across the cill. There is a concrete bypass pipe midway along the weir. The left bank is faced with granite blocks. Also on this bank, immediately upstream from a concrete footbridge across the river, is the intake to the pipe which leads to a nearby well house (HB16/01/051) and eventually to the Conduit. There is a small flow gauging station of recent date over this intake point.

Historical information

Constructed by Fisher and Le Fanu for the Belfast & District Water Commissioners and opened in 1901 as part of the Mourne Scheme to supply Belfast with water. Until the completion of the Brackenagh Tunnel in 1903 (between the Silent Valley and Dunnywater), the Annalong River was the sole supply to the Conduit. Originally there was a simple wooden hut at the abstraction point, but this has gone. Although most of the water from this river is now abstracted further upstream at the Bignian Tunnel (HB16/01/041), this weir and intake still remain in use. The footbridge dates to c.1964.

Primary Source:
1. DOE Westland House, Old Westland Rd, Belfast – drawings 3A17, 3A47, 3A58.

Criteria for listing: architectural interest

Not listed

Criteria for listing: historic interest

Not listed

Evaluation

This interception weir, and that across the Kilkeel River, provided the sole water supply to Belfast from the Mournes prior to the opening of the Silent Valley reservoir in 1933. It is therefore of some historical interest and also has group value in terms of its functional connection with the nearby well house and Mourne Conduit.