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How Wessex Water’s Trenchless Technology Team is training young engineers

The formation of Wessex Water’s Trenchless Technology Team allows young engineers to access expert mentors while working on real-world problems and forging original solutions for the management of cured-in-place pipe (CIPP) linings and other trenchless interventions.

by Julian Britton, Trenchless Technology Manager, Wessex Water

As one of the leading water and sewerage companies in the UK, with some 34,000 km of sewers, Wessex Water has constantly innovated to provide a better service at a lower cost. The formation of its Trenchless Technology Team in 2004, based at Kingston Seymour in Somerset, has paid dividends in mitigating the impact of renovation and renewal of sewers upon customers.

It became evident in those early days that solutions offered by third parties and contractors from around the world did not necessarily align with the needs of the water company in striving for high quality sewer renovation with assured longevity.

The Trenchless Technology Team developed an approach to searching out innovative solutions and managing CIPP linings and other trenchless interventions with high levels of controlled risk. The old adage of ‘necessity is the mother of invention’ has never seemed more relevant.

The team collaborated with a number of well-recognised experts from around the world to bring challenging renovation schemes to fruition. Dr Dec Downey of Trenchless Opportunities has been involved from the outset and has consistently ensured the more complex schemes have been completed to meet the expectations of the internal company clients, while satisfying any concerns of third parties.

As Dr Downey acted as a mentor to the team, the senior management reciprocated by mentoring junior engineers and interns.

This internal mentoring initiative, now ten years old, grew from a lack of available and suitable educational engineering courses within the UK and further afield. Consequently, the Trenchless Manager established a suite of detailed internal courses covering CIPP, man entry GRP panel lining, pipe bursting and HDD.

This initiative was supported by successive Chairmen of the UKSTT from Russell Fairhurst in 2007 through to Ian Vickridge, via the ‘Young Engineer Award’ scheme. In the last ten years, the award has been awarded to five junior engineers developed by the Trenchless Teams mentoring program.

In addition, to promote trenchless education, current Vice Chairman and soon to be Chairman of the UKSTT, Matthew Izzard and his team have developed the first in a range of master classes, with both CIPP and HDD classes held to date.

“It goes without saying that young people are the future, building on the experience and knowledge of the leaders in our industry. One of the core values of the UKSTT is education and the development of students and young professionals,” says Mr Izzard.

“The concept of rewarding outstanding work with a major industry award and a £2,000 (US$2,566) bursary recognises this contribution and, hopefully, inspires others to follow the path made by previous award winners. The support that Wessex Water, and Julian Britton in particular, have made as UKSTT Patrons in promoting this initiative has been testament to their program.”

Helen Isaacs using an endoscope to inspect voids.

Trenchless International covered the initial five years of Wessex Water’s mentoring program in a previous edition,1 highlighting the cross fertilisation of ideas as the winners of the UKSTT award used their bursary to visit sewerage companies in Singapore, Japan, Australia, Hong Kong and the US.

Ms Selwyn undertook trials in Sturminster Marshall in Dorset, England, in gravel beds with artesian pressures, previously reported in Trenchless International,2 using various sealing materials injected through the manhole wall into the host geology. Her work culminated in the choice of a polymer modified cementitious grout with a quick set anti-washout characteristic ideal for these difficult locations and she collaborated with Germany’s Institute for Underground Infrastructure (IKT) as part of manhole sealing research.

“The mentoring scheme meant I was able to use these trials for my final year project. Last September I moved to London and started on the civil engineering graduate scheme with Transport for London,” says Ms Selwyn.

“In the future, I hope to start a part-time master’s degree in transport engineering, which will be supported by Transport for London. The support that was given from Julian’s mentoring program has been vital to the start of my career in civil engineering.”

As the project came to fruition, Ms Selwyn was able to demonstrate the grout’s robust sealing capabilities in Minehead, Somerset, sealing manholes in deep beach cobbles with a high volume of voids, under pressure from the Atlantic Ocean. Her work reduced the saline intrusion into the sewage works by over 25 per cent.

Brazilian intern Franceili Thums, also at the University of the West of England, worked for Nathan Hand, the team leader of special projects. Mr Hand managed Ms Thums’s use of the IKT extensometer, known as the MAC system, which is used for analysing the existing residual structural capability and longevity of tunnel linings.

Ms Thums brought this non-destructive test equipment together with the latest CCTV/laser survey platform from Redzone USA in order to identify and prioritise structural defects in large diameter tunnel linings. Her work allowed Wessex Water to allocate annual capex to the most deserving assets. Her paper will be printed in an upcoming edition of Trenchless International.

Working alongside Ms Thums was Helen Isaacs, a special projects junior engineer. Ms Isaacs came with a detailed understanding of the ‘Infoworks CS14.5’ hydraulic modelling experience, and was encouraged to add value to the team’s knowledge comparing the hydraulic conductivity of an existing 375 mm diameter sewer in Wiltshire, England before and after lining. This confirmed Wessex Water’s long-held belief that on occasion you can convey more flow through a reduced pipe diameter after lining, where the lining presents a lower coefficient of friction in terms of Ks value or Manning’s.

Ms Isaacs has recently completed a roll out of the ‘styrene protocol’ associated with odour emissions post CIPP resin cure. This procedure mapped styrene away from the lining environment in contours to establish the free styrene in parts per million.

The project confirmed that Wessex Water’s management of styrene met the requirements of British legislation and the presentation gained approval from the Governments Health and Safety Executive. The protocol formed part of a winning submission to the Royal Society for Prevention of Accidents (ROSPA) ‘Sector Award’ in 2017.

Nathan Hand managing the MAC extensometer with IKT of Germany.

“I have also learnt a huge amount from the wider team, who have a wide range of specialisms and are always ready to discuss and advise on problems that crop up. This role is hugely varied and every project has its own challenges, meaning I never get bored,” says Ms Isaacs.

“Wessex Water are supporting me through a Civil Engineering HNC, to add to my MSci geography degree. I have also benefited from a course with the Geotechnical Academy, which has meant I have been able to investigate structural issues within tunnels directly.”

Her works continue to investigate gross metal loss of rising (force) mains to establish longevity under given working and surge pressures, and how CIPP pressure liner solutions may be implemented to enhance their capabilities.

The team are working on a matrix of known liners from around the world, understanding their physical properties, and how specific liners may be suited to certain conditions. This work will augment the release of EN ISO 11297- 4 in the near future.

The mentoring program would not have seen these successes without the symbiotic relationships and collaboration with the ISTT and UKSTT. Recent winner of the UKSTT ‘Young Engineer Award 2016’ Nathan Hand was asked to write the company’s technical standards for HDD and drilling on gradient.

Mr Hand was hosted on a secondment to Arizona University in Phoenix by Dr Sam Ariaratnam, an authority on these forms of Trenchless Technologies, and then travelled to the NASTT show in Washington for a week of courses.

Now a leading member of the team, Mr Hand has refreshed Wessex Water’s approach and understanding of WRc SRM Type 1 GRP panel lining. He has adjudicated on numerous tunnels, completing petrographical analysis of corroded concrete that has been subject to hydrogen sulphide attack.

He subsequently designed the shells and completed works on site, most recently in 220 m of 1200 mm diameter Flexilok tunnel in Bournemouth, subject to 19 m overburden of saturated wind-blown sands.

Matthew Izzard is enthused by the attitude of these young engineers as a whole and met Mr Hand in Washington.

“It was great catching up with Nathan and hearing what a great year he is having. The bursary awarded to him by winning the UKSTT Young Person’s Award has allowed him to travel to Washington and meet many of the leading figures in the industry, adding to his experience and knowledge,” says Mr Izzard.

“We have invited Nathan, as our guest, to the UKSTT Awards Dinner in October to talk to us about his year and the work he has been doing to inspire other young people to achieve all they are capable of.”

In discussion with the young engineers, a number of factors associated with their trenchless activities are cited that cannot fail to impress, including:

  • Excavation avoidance; the CIPP renovation of some 25 km/a avoids the excavation of some 76,000 t to tip per annum, obviating the need for an equivalent of new imported bedding and removing 15,000 lorry movements from our highways.
  • CO2 reduction; calculations by the Trenchless Team have identified a 95 per cent reduction of carbon emissions when compared to the equivalent open cut interventions.
  • A conservative £8 million (US$10.26 million) saving by avoiding open cut in preference to No Dig solutions.
  • Major socio-economic savings to our customers by mitigating mobilisation periods on roads, reductions in dust and noise levels, etc.


The drive to understand the chemical and physical attributes of CIPP lining materials, pipe insertion plastics, polyolefins and so on, allows the young engineers to consider increased longevity of assets, anticipated as well beyond the 50 year life expectancy of materials, ensuring a legacy from which they derive satisfaction.

In conclusion, as a water and sewerage company, Wessex Water is well placed as a client to understand ‘needs’ in terms of viable solutions and have given the young engineers in the mentoring program free rein to explore new solutions and undertake exciting new in-house research and development.


Trenchless International, October 2013

Trenchless International, Winter 2017

This article was featured in the Summer edition of Trenchless International. To view the magazine on your PC, Mac, tablet, or mobile device, click here.

For more information visit the Wessex Water website.

If you have company news you would like featured in Trenchless International contact Assistant Editor Nick Lovering at

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