HomeProjectsCross Solent Water Main

Cross Solent Water Main

Isle of Wight

In 2003, Southern Water began a £15m scheme to replace a pair of pipes supplying a quarter of the water used on the Isle of Wight, off England's south coast. In August 2006 VolkerInfra operatives started to drill in Lepe, on the mainland. They bored the first of two 1.2km long holes with a 61cm drill bit and pulled the single length of pipe into it in December by hauling it in with the drill string as it was withdrawn from the hole.

Curabitur

Care had to be taken because the beach at Lepe is an area of Special Scientific Interest. Drilling at the island end had other sensitivities to consider, with a soundproof barrier being constructed to minimise disturbance to residents of a cottage close to the drilling site.

The three remaining sections of pipe, two at the Isle of Wight end and the one remaining at the mainland, were pulled into their holes in February and March 2007. With this, phase one of the project was nigh-on complete, with the fitting of the new mid-sections of the main, underneath the bed of the Solent, being scheduled for early 2008 in phase two of the project.

In spring 2008, VolkerInfra completed the second and final phase of the project. After preparations, the team laid the mid-sections. Thanks to The Hornblower technology that its parent company, Visser and Smit Hanab, developed, each 2km pipe took just a day and a half to lay. Once tested and disinfected, concrete mattresses could be laid to prevent scouring by the sea. The new pipes are now set to supply the island's water needs for summers to come.

Key features:

  •  In-house design and engineering, trenchless techniques and marine capabilities
  •  4 no. horizontal directionally drilled landfalls: longest 1200m, to cross environmentally sensitive coastal areas
  •  flexible pipeline between drillings directly buried in seabed under Solent
  •  in-house developed and built burial tool
  •  transport of PE pipes for drillings by towage directly from factory in Norway; transport of flexible pipelines on large reels from factory in Denmark
  •  marine installation, burial, divers tie-ins on Solent: strong currents and busy shipping (both commercial and pleasure craft)

Facts and figures

  • Type of works:
    Marine pipelines
  • Client:
    4 Delivery / Southern Water
  • Value of project:
    £15m
  • Duration of project:
    2006 - 2008
  • Roles/responsibilities:
    Main contractor
  • Contract type:
    Lump sum (Engineering Design & Construct)
  • Project categories
    Trenchless techniques
    Marine works
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