Scottish Water’s tunnelling machine, Molly the Mole, has completed a 1.2km storm water sewer under Airdrie. Named by local school pupil Aimee Stewart, the machine was raised from the ground at an event attended by local councillors Jim Logue and David Stocks.
Now that the project is complete, the storm transfer sewer can be connected to the local sewer network and made operational later in the year. Designed to improve water quality in the South Burn and reduce the risk of flooding at Cairnhill Road, the project will also facilitate the removal of eight additional properties from the flood register.
The tunnel runs from Airdrie Railway Station car park to a Brownfield site behind Club 300 Bingo in Coatdyke. With an internal diameter of 2.44 metres and an external diameter of just over 3 metres, the tunnel depth varies to as deep as 40 metres.
Ground conditions across the track of the tunnel vary from boulder clay and mudstone to sandstone and mine workings. Although the construction team came across a small void and some heavy water ingress, no major issues have emerged during the tunnelling process.
Brian Dalton, Project Manager for Scottish Water, said:
“During 2011, our delivery partner Byzak Ltd successfully completed the 1.2km tunnel below Victoria Place using Molly the Mole, who ended her journey in late December 2011.
“The tunnel was needed as part of the overall solution for the project. There are currently discharges to the local watercourses which breach our consent with SEPA, our environmental regulator. These flows will now be transferred via interconnecting pipework from their source, before being transferred along the to a storm tank. Following this, the storm flows will discharge to the North Calder water.
“Our original route was actually going through the centre of Airdrie, however when we were in talks with Byzak at the planning stage they highlighted an alternative route that caused much less disruption, required less surveying work and would be quicker to complete.
“Meeting the programme dates has been the biggest challenge so far. We set Byzak a tight programme and they have done very well to stick to the foreseen timescales thus far. We are happy that they have completed the tunnel without any major delays and on schedule.
“We thank the community for their continuing patience and understanding while we carry out this essential work.”
Work in Cairnhill Road and Broomknoll Street included the upgrading of an existing sewer network and is now complete. As a result of this phase of the project, Scottish Waters expect a significant reduction in the high flood frequency of the area. Additional work has been carried out adjacent to the Airdrie Business Centre.
In the coming months, Wullie Worm – a tunnelling machine named by Sikeside Primary pupil Ethan Lynch – will create smaller tunnels under the area surrounding the railway station and the adjoining streets. These works will in turn connect the new storm transfer to the local network.
In order to enable the tunnelling process, a phased construction programme will take place at the car park to the rear of Stirling Street to maximise available car parking space for local residents. North Lanarkshire Council has authorised the works and this phase of the project is due to be completed by March 2012.
Geoff Aitkinhead, Scottish Water, said:
“This is one of the largest projects that Scottish Water is doing in Scotland in the 2010-2015 investment period.
“We have regularly communicated with the local community to ensure that the work has as little impact as possible. Our team has also volunteered for a community event cleaning up Centenary Park in Airdrie by weeding plants, painting and cleaning up play equipment.
“Local businesses and residents are kept aware of the latest news on the project through letter drops, posters, press releases, school bag drops, face to face meetings and our online channels.”
The entire scheme is expected to be completed by the autumn of 2012 and will significantly improve water quality in watercourses across Airdrie and beyond.