A pipeliner developed for use in earthquake-prone regions, has been used on a trunk sewer main damaged by unstable terrain on a cliff-side in Portland, Dorset.

According to water supplier Wessex Water, the repair is the first of its kind in the UK, with the German-manufactured liner installed despite considerable challenges posed by the location of the work. A section of the Portland Combined Trunk Sewer, next to the lower South West Coastal Path at Grove Point, 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 the team at RSM Lining Supplies Global team to come up with a rapid and viable solution. RSM’s technical business development manager, Richard Wortley, recommended and supplied the innovative earthquake liner, manufactured by UV material specialist BKP Berolina.

Originally engineered for tremor-prone regions, the liner is uniquely designed to self-support the pipeline in the event of ground movement or collapse.

The solution is expected to ensure that Wessex Water do not have to implement a hugely expensive alternative, that would have involved them over-pumping in the environmentally-sensitive area to safely divert flows from the sewer towards its treatment sites.

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 5km 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.”

Wortley, said: “Throughout the operation, the team’s coordination was exemplary. 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.’’