Manse Street Infra

Project Details:

The project is part of three schemes which delivered up­grade works to Howden Water Treatment Works, provide a new 12ML clear water tank and then main out the existing Manse Street works with a 12km pipe­line. AG Wilson delivered the construction element of the project and managed drilling works under the River Tweed.

The scope of the project was to install 11.25km of 400mm diameter water main from the new Howden CWT to the inlet flowmeter at Manse Street DSR in Galashiels. An additional 1.2km of 280mm and 400mm pipework was installed to tie into local networks.

Major aspects of the works included;

• 1no River Tweed crossing, twin 400mm HDD of 450m length - A 300 tonne drilling rig successfully completed the first of two 500m drives under the River Tweed, the A7 and a high pressure gas main. Using the drill lessened disruption to customers on roads and reduced the risk of open cutting around a gas main.
• 10no High and medium pressure gas main crossings
• 15no Road crossings
• 3no large diameter live network connections
• 5no small river crossings – isolated open cut
• 450mm of carriageway construction through rock

The works were environmentally sensitive in nature due to works near watercourses. The River Tweed is a SSSI (Site of Special Scientific Interest) with a number of ecological constraints associated with the crossing relating to salmon, otters and crayfish. The team liaised with many stakeholders including SEPA, The River Tweed Commission and The Tweed Foundation