Tunnel boring machine completes key water main in Glasgow

A state-of-the-art tunnel boring machine has completed the installation of a key part of a new trunk water main in Glasgow, as part of a multi-million-pound project to improve Scottish Water’s network in the south-west of Glasgow.

The tunnel, which goes below the M8 motorway, Paisley Road West and the Glasgow-Ayr railway line, is part of more than seven miles of new water mains being installed which will connect the Glasgow area’s network and the system in Ayrshire and which will benefit almost one million customers.

The hi-tech machine or TBM, has installed a 252-metre-long tunnel and section of water main from Broomloan Road in Ibrox, in the shadow of Ibrox Stadium, to the north side of Bellahouston Park.

The TBM – named Tytana by Ibrox Primary School pupil Manha Raheel who won a competition to name the impressive machine – installed the tunnel at a depth of up to 20 metres below ground, the equivalent height of a seven-storey building, while thousands of road and rail users above went about their daily business.

Dominic Flanagan, Scottish Water delivery manager, said: “The installation of this particular part of the new water main using the TBM is arguably the highlight of this project so far and we are delighted to have completed it.

“Everything went well with this very challenging and complex operation and we were really pleased that our guests from Ibrox Primary School FC were able to join us and see the tunnelling start.

“Linking our supply systems in Glasgow and Ayrshire will ensure that high quality drinking water can continue to be supplied to current customers and for generations to come.

“The investment in below-ground infrastructure will also support the continued development above ground in communities across these areas and will enable them to continue to grow and thrive."

About 1,311 tonnes of rock, such as sandstone and mudstone, were excavated and taken to landfill. A total of 100 sections of pre-cast concrete pipes each measuring 2.5 metres in length were installed, taking the total weight of the tunnel to about 500 tonnes.

Connecting the networks will provide a two-way water supply between the Milngavie Water Treatment Works (WTW) system, which provides water for more than 700,000 people across much of the Glasgow area, and the Bradan WTW system which supplies more than 200,000 customers across much of Ayrshire. It will also benefit almost 50,000 customers in East Renfrewshire.

In the event of a disruption to water supply in either Ayrshire or Glasgow, the new system will allow millions of litres of water to be transferred in either direction, minimising the impact on customers if there is a burst main or other operational issue.

The new water main is being installed in the Ibrox, Mosspark, Pollok, Priesthill, Nitshill and Parkhouse areas of Glasgow and will run from Ibrox to a reservoir storage tank in the Parkhouse/Darnley area. 

A new pumping station is being built at Ibrox which will push water to the existing pumping station in Parkhouse/Darnley for onward distribution to Ayrshire. 

The work in the south of Glasgow is the third and final stage of the overall investment which has already delivered improvements in Ayrshire.

The design of the new network incorporates carbon reducing construction materials and methods including innovative self-restraining pipe. Solar panels will also offset the power demands at the new Ibrox pumping station, with the new mains using gravity to reduce power use by 60%.

Four tunnels – one at Ibrox under the M8 motorway and the Glasgow-Ayr railway line, another under the Paisley Canal railway and White Cart Water, another under the Glasgow-Barrhead-Kilmarnock railway and one under the Levern Water – will form part of the route of the new main. 

The tunnels under the Glasgow-Barrhead-Kilmarnock railway and the Levern Water have already been completed.

The start of the construction of the tunnel at Ibrox, which is the biggest of the four and was carried out for CWA by HB Tunnelling Ltd of Doncaster, was witnessed by three pupils from Ibrox Primary School, located near the project, who took part in a competition to name the TBM.

A team of six people worked on the tunnelling.

After the tunnel was installed, 22 sections of water main made from ductile iron were placed inside it, using a crane to lower the pipe sections down and a winch to pull them through the tunnel and into position before they were grouted and sealed.

The project is being delivered for Scottish Water by Caledonia Water Alliance, its alliance partner, and is expected to be completed in 2024.