Installing an ‘earthquake liner’ on England’s south coast is a ‘seismic step forward’ for sewer repairs in the UK, says Wessex Water.
The utility company teamed up with industry specialists to devise a ground-breaking solution for a trunk sewer pipe damaged by unstable terrain on a cliff-side on the isle of Portland, Dorset.
A section of the Portland Combined Trunk Sewer next to the lower Southwest Coastal Path had been damaged by ground slips caused by heavy rain earlier in the year, forcing the area to be closed to the public due to safety concerns.
After Wessex Water crews were initially unable to get to the remote site – a Site of Special Scientific Interest (SSSI) – to carry out significant repairs, they turned to RSM Lining Supplies Global Ltd for help.
And despite considerable challenges, the liner was successfully installed in the first repair of its kind in the country.
Richard Wortley, of RSM, recommended and supplied the product, manufactured by BKP Berolina.
The solution should ensure that Wessex Water don’t have to implement a hugely expensive alternative that would involve locating over-pumping equipment in the environmentally sensitive area to safely divert flows from the sewer towards its treatment sites.
Originally engineered for tremor-prone regions, the liner is designed to self-support the pipeline in the event of ground movement or collapse.
Wessex Water’s Southern Sewer Renovations Construction Manager, Paul Musselwhite, said: “This was a complex project to help protect the integrity of a sewer pipe next to the coastal path that had been damaged by ground movement.
“By our estimates, the alternative would have meant we were looking at installing an overland pipeline of more than five kilometres at a calculated cost of as much as £14 million in a SSSI area until 2030.
“Instead, we worked closely with RSM to come up with an innovative solution that trialled a product that had never been used in this country before, and a special note of appreciation goes to them for allowing a key team member to oversee and advise.
“Its successful installation is a tribute to our collaboration with RSM and the fantastic support from the liner manufacturer in Germany, who flew over a representative to help oversee the installation.
“It is also testament to the specialist skills that our colleagues can bring to such projects that it was installed using our own in-house resource and teams, rather than an external contractor.
“Without the expertise and collaboration of all, this ambitious scheme would have required significantly more time and resources to achieve the same outcome.”
Previously, Wessex Water had monitored and carried out only minor work to prevent the situation from deteriorating but with ground instability in the area increasing, RSM oversaw the installation of three UV ‘earthquake’ liners by contractors Lining Division Ltd in December 2024.
Each measuring between 800 and 975mm in diameter and totalling 400 metres in length, the liners were transported from Germany in custom crates, with special storage conditions considered due to the location of the site.
The liners were carefully delivered, using equipment including tractor trailers, with the installation carried out under the supervision of an on-site specialist, to ensure the highest standards were adhered to.
Richard Wortley, RSM, added: “Wessex Water’s sewer renovation team maintained continuous pipeline flow throughout the repair, using a complex setup of 12 tankers and four tractor trailers operating around the clock. This seamless collaboration minimised disruption whilst ensuring the safe and efficient installation of the liners.’’
