Giant tunnel boring machine emerges at Knutsford after completing underground drive

A giant tunnel boring machine (TBM) has completed the first stage of its underground journey from Moor Pool to Knutsford Wastewater Treatment Works as part of United Utilities’ £48m upgrade to the sewer network.

The 40-tonne machine – named ‘Lily’ by pupils at Bexton Primary School after the nearby River Lily – began its journey from Parkgate Industrial Estate before breaking through at Knutsford Wastewater Treatment Works.

The boring machine will now return to Parkgate and lowered underground before embarking on the second part of its journey - this time travelling in the opposite direction - to Moor Pumping Station near Moor Pool.

The scheme will provide extra stormwater storage and improve water quality in Moor Pool by installing a 1.8km storage tunnel between the water company’s pumping station at Moor Pool, and its wastewater treatment works in Knutsford.

Once complete, the tunnel will be 20 metres underground at its deepest point, two metres in diameter and will store up to five and a half million litres of stormwater in periods of heavy rainfall, before being treated at Knutsford wastewater treatment works.

Maria Fletcher, County Business Lead for Wastewater in Cheshire said: “This project highlights our ongoing commitment to improving water quality in the county, and how working closely with partners can offer alternative and innovative solutions to stormwater management in protected areas.

“This is also a remarkable feat of engineering, delivering major underground infrastructure that will store up to five and a half million litres of stormwater in periods of heavy rainfall - that’s equivalent to two Olympic sized swimming pools - and reduce storm overflow activations.”

The project forms part of United Utilities’ wider commitment to the largest investment in water and wastewater infrastructure in a century across the North West.

The company will be spending more than £13bn over the next five years to protect and enhance over 500km of rivers, lakes, and bathing waters whilst safeguarding drinking water supplies for millions of customers.