Shieldhall Tunnel

Scotland, United Kingdom

Year

2018

Duration

4 years

Cost

£100m

Location

United Kingdom

Project achievements

Solved the problem

Shieldhall Tunnel

Area improved

Removed considerable pressure from ageing infrastructure.

Used engineering skill

Constructed using a special tunnel boring machine.

Flooding and water quality addressed by a new tunnel

In June 2002 a month’s rain fell on Glasgow in just one afternoon leaving the south side of Scotland’s largest city under several feet of water. The existing sewer network simply didn’t have the capacity for such volumes of water.

A new 5km waste-water tunnel opened in 2018 has reduced flooding at key locations and improved water quality in the River Clyde and its tributaries. Big enough to fit a double-decker bus inside, the new tunnel is the biggest investment in Glasgow’s sewer network in more than a century.

The tunnel was constructed using a special tunnel boring machine and the route carefully selected to minimise disruption.

The tunnel is the culmination of a 5- year investment programme put in place by a partnership comprising the Scottish Government, Scottish Water, Glasgow City Council and Scotland’s environmental protection agency (SEPA). This partnership is also known as the Metropolitan Glasgow Strategic Drainage Partnership (MGSDP), who worked together to address the weaknesses within the sewer network throughout Glasgow.

The £100 million strategic tunnel project is the biggest watewater storage tunnel in Scotland and addresses problems in the area served by the Shieldhall Waste Water Treatment Works.

Did you know …

Biggest investment in the water network since the Victorian era.

Project achievements and benefits

In 2013 the first conversations took place with the communities along the tunnel route who had no idea of what to expect, with many picturing considerable disruption and conditions that would shame the early years of coal mining.

Through upfront and consistent communications, these fears where alleviated and in fact the project was never the subject of environmental health investigation or enforcement. The development showed that through careful planning and collaborative working, infrastructure improvements of this size can be delivered in and around other major infrastructures such as railways and motorways.

The team also showed that with early engagement, that projects of this size which carry the potential for disruption can be achieved little or no negative public or stakeholder commentary.

This project is unique and groundbreaking not only for Glasgow but for the whole of Scotland. It will remove considerable pressure from ageing infrastructure while preparing it for future growth. The creation and delivery of the Shieldhall Tunnel also provides considerable insight for other similar projects and will show how to develop and construct them in challenging ground conditions.

Project elements

At five kilometres long, the Shieldhall Tunnel begins in Craigton, next to homes and properties that had never experienced anything of this magnitude before. It continues under a major access route into and out of the city, under Bellahouston Park, then under the Paisley Canal railway line and the M77 motorway, before heading under Pollok Park and ending in the well visited and utilised Queens Park.

The tunnel is 4.65m in diameter, big enough to fit a double-decker bus inside and more than five times as long as the Clyde Tunnel. Work began in mid-2014 and was completed in the summer of 2018 including preparatory work, mine working consolidation and utility diversion work. This project delivers a genuine positive change and improvement to many homes and businesses that have faced considerable upheaval following a number of flooding episodes.

While the city has had a long association with the Glasgow Subway, the Clyde Tunnel and its coal mining heritage, a process of educating, explaining and gaining stakeholder buy-in had to be conducted. The mining consolidation the project delivered, removed considerable concerns about the management of old mine workings along the route, even identifying and reinstating undiscovered mine shafts.

It dealt with and provided considerable learning for the management of Clyde Alluvium, which will benefit any future deep excavation of tunnelling in the city.