Water & Wastewater Treatment Magazine
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16 | XXXXX 20XX | WWT | www.wwtonline.co.uk The Works P roject constraints oen dictate an engineering concept. In some cases, these constraints can be so formidable that the only solution is to invent something completely new. Thames Water's Kings Scholar Pond (KSP) sewer rehabilitation scheme is one such project. The innovative keyhole engi- neering design for this £15 million project, in one of London's busiest areas, created minimal disruption to the public and no impact on roads or underground rail. In addition, designer Stantec's state-of- the-art solution enabled the 1840s brick- built Victorian sewer tunnel to remain in full wastewater operation throughout. The stakes were high because if the KSP structure failed, its location – on a busy road junction above Baker Street tube station and at the Baker Street/Marylebone Road intersection – meant it would inflict severe disruption to London's road and underground rail networks. and construction of this project. En- hanced stakeholder engagement was key to the successful project delivery, with Stantec's design team and Skanska and Balfour Beatty Construction teams working in close collaboration with Thames Water, London Underground and Transport for London to develop the solution. All stakeholders contributed significantly to the design develop- ment to ensure the specific needs and outcomes of all parties were met. The KSP sewer, buried 2.1m beneath the junction of Baker Street and Maryle- bone Road, and running above London Underground's Hammersmith and City Line, was found to be showing significant distress during a routine inspection. Constructed within the crown of the brick London Underground tunnel, the sewer spans 10m between support points. In addition to severe structural cracking identified within the sewer, the The use of keyhole engineering on Thames Water's Kings Scholar Pond project saved money and carbon while keeping London moving Through the keyhole 16 | OCTOBER 2019 | WWT | www.wwtonline.co.uk However, rather than using a tradi- tional dig solution, Thames Water took a different approach, saving approximately £23 million and over 26,000 tonnes of embodied carbon as well as avoiding the need to disrupt rail or road users. "We are all immensely proud of this project," Mark Taylor, head of programme management (waste) for Thames Water, says. "It was about being sympathetic with the environment, harnessing innova- tion and keeping London flowing both above and below ground. "It required huge innovation and new solutions because of the extraordinary constraints and high consequence risks. The design and project execution were ex- cellent and mitigated a significant risk on London's sewerage network and ensured the continued service of the King's Schol- ars' Pond Sewer for a further 120 years." Thames Water utilised its eight2O alliance contract to procure the design A worker cuts out PFC ribs