‘Super sewer’ unearths the history of the Thames

  • Construction of London’s ‘super sewer’ has unearthed a 190-year-old discovery
  • A Victorian dry dock was buried deep into the bank of the River Thames
  • Our FLO Central team is working with archaeologists to preserve the find

A vast, 32-metre diameter shaft on the south bank of the River Thames, near Battersea Power Station, extends 60 metres deep into the earth – far enough down to stand Nelson’s Column, with room to spare.  

Unearthing the past

Excavating so deep into the earth inevitably brings surprises. With large-scale projects such as this, it is standard practice for our teams to work with archaeologists from the start to ensure any historic finds aren’t damaged as we excavate. 

But, when a section of sodden wooden planks and posts were exposed just a few metres down, even we were surprised to discover the extent of what lay beneath. 

Just metres away from the Thames river bank, a large section of a well-preserved timber dry dock, comprised of retired barges, gradually emerged. Working alongside our team, MOLA (Museum of London Archaeology) Headland Infrastructure worked around the clock to recover the artefacts. As the discovery took shape, the team realised the exciting find dated back around 190 years, painting a detailed picture of Victorian life by the Thames. The wooden hulk, hidden for almost two centuries, evaded the attention of those constructing above it decades ago, as they drove concrete piles straight through the deck. 
The dock is thought to have been owned by a timber merchant named Edward Kilsby in the early 19th century. 

According to historical records, Kilsby went bankrupt in December 1827 and the site was acquired by its new owner, John Heighington, in 1829. Heighington apparently redeveloped the site for boat building, or possibly for boat breaking, incorporating a number of old barges.

More remarkable still, beneath a stretch of deck, a perfectly preserved empty barrel was found, inscribed with ‘1830’ – which helped date the find.

The waterlogged conditions at the side of the Thames, free from exposure to air, presented perfect conditions for preserving the wooden structure.

Boats and barges

This is not the first archaeological artefact found at a Laing O’Rourke site. In 2013, when Laing O’Rourke began work on a specialist cancer centre at Guy’s Hospital in London, the project team uncovered the remains of a Roman boat. 

The piling on the project was installed to a range of depths – the deepest going down 42 metres. When the team discovered the boat, the basement structure had to be constructed around it. They also had to include a 2.5 metre-thick concrete transfer slab, which protects the boat and allows it to be removed at a later date.

Georgian water works and Bedlam skeletons

In Watford, the team working on the INTU Watford shopping centre project uncovered an old well and water tank when they began digging out the basement. Archaeologists suspect they date between 1700-1750 and are a remarkable Georgian discovery.

Work on Crossrail at Liverpool Street was involved in uncovering the Bedlam burial site, comprising approximately 3,000 skeletons. Sixty archaeologists oversaw the excavation of the bones over four weeks. Archaeologists from MOLA have found around 10,000 artefacts spanning 55 million years of history throughout the Crossrail project’s lifecycle. 

Next steps on the Tideway Central project

MOLA’s specialists are working through the physical finds and cross-referencing these with historical records. In the coming weeks and months, as our understanding of the find increases, the team expect intriguing stories to emerge. 
James Delieu, our Communications Manager on the project, said: “Finds like this are a great opportunity to learn more about the development of the river and illustrate how people have relied on it for centuries. The Thames has a rich and interesting history and our project will play a significant part in the next chapter of it. The works will clean up this iconic river and allow Londoners and visitors to enjoy it for years to come.”

About the project

The Thames Tideway tunnel is a £746 million project that aims to create the largest stretch of London’s new £4.2 billion ‘super sewer’, being delivered by a joint venture of Ferrovial Agroman UK and Laing O’Rourke (Flo). The Thames Tideway Tunnel is a much-needed piece of infrastructure in the city. London's sewerage system is no longer fit for purpose and spills millions of tonnes of sewage into the tidal section of the river every year. The tunnel is, in effect, a giant reservoir under the Thames that will capture raw sewage overflows that would otherwise end up in the river. The 25 kilometre tunnel project comprises 24 sites and 34 sewer overflow outlets, starting at Acton Storm tanks (Ealing) in the west and terminating at Beckton Sewage Treatment Works (Newham) in the east. The Flo joint venture is overseeing eight of these sites in the centre of London. It will service the river for the next 100 years, and enable the UK to meet European environmental standards.

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