Scottish Water

Conditions Of Contract
NEC 3 Option A

47 Weeks

Contract Value


Inaugurated in 1859 by Queen Victoria, the 42km long original Katrine Aqueduct has the capacity to deliver 50mgd of raw water by gravity flow, from Loch Katrine in the Trossachs to storage reservoirs at Mugdock on the outskirts of Glasgow and is the primary source of water serving a large part of the Greater Glasgow conurbation.

The aqueduct has a significant number of structures, which include 40km of twin tunnels, substantial pipe-bridges, a large intake structure, siphon pipelines crossing valleys, cross-over chambers, together with control valve houses and this project involved extensive structural refurbishment and repairs to maintain security of supply.


A detailed logistical plan was developed to facilitate the closing down of parts of the structure to allow the repair works to be undertadock streeobanken whilst maintaining the supply of raw water to the treatment works.

Works consisted of; steelwork replacement/support/repairs across 16nr structures, the largest of which was the 200m long aqueduct bridge in the Duchray Valley which comprises a rectangular cast iron trough 2.4m x 2m, some 16 m above ground level; masonry, concrete repairs and re-lining over a 4km section of 2.4m dia tunnel.

Refurbishment of 33nr large diameter valves and penstocks; and miscellaneous works including; scour repairs and protection to an undermined pipe-bridge abutment carrying three 42″ mains over the Endrick Water with extensive special protective measures to prevent silting of this important watercourse during the mid-river construction work, and slip lining a 27m length of corroded 42″ main.

With over thirty historic Listed Structures on the aqueduct, the essential repair programme required extensive consultation and approvals throughout.

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