London super sewer to cost £300m more than originally thought


The project building a ‘super sewer’ beneath London from 23 above ground sites is now 40 per cent complete, say builders.

The first kilometre of the Thames Tideway Tunnel, which will relieve
the strain on existing sewers, has now been dug from Battersea to beneath

New estimates see the project finishing on time but with a £300 million
budget increase – an extra eight per cent.

But this will not mean any further cost for bill payers. The £20-25 increase in Thames Water charges, started four years ago, will already
cover the increase.

The project will reduce the amount of raw sewage currently dumped into
the Thames by 90 per cent. This is the same as eight billion toilets flushing
straight into the river every year.

Engineers have now finished the most unpredictable part of the project,
involving setting up sites, machinery and planning.

Two more tunnel diggers have started their journeys to dig the 25-
kilometre tunnel under the Thames.

Tideway’s chief executive, Andy Mitchell, said “As we approach the
half way point of construction, the time is right to update our cost estimate.

“The most important thing to say is that there will be no impact on the
estimated cost to Thames Water bill payers and to recognise that our
teams have done a great job in getting us this far and keeping us on

Every day we get closer to our aim of giving London a cleaner

There are 23 Tideway building sites across London, including seven
pieces of land being built up from the Thames.

The new embankment in Putney is to become a public space by the river with a good view of the boat race, which took place last weekend.

Further down in Wandsworth, a second tunneller is digging from a
site by the River Wandle.

It was launched by Wandsworth’s mayor two weeks ago and will dig south toward St George’s Park.

When it reaches the park it will be removed and taken back to the first site, where it will dig north to the main tunnel under the Thames.

The north corner of the park currently has a 25-metre deep shaft dug into it, and this will be landscaped with a new seating area when the project is finished.

Five pumping stations south of the river will have deep shafts dug below them to connect them to the new sewer.

Pumping stations in Greenwich and Rotherhithe will have 60-metre shafts dug below them.

These will be part of a 4.5-kilometre section of pipe, connecting to the main pipe north of Bermondsey.

This section will be dug by the smallest drill, named ‘Annie’. Traditionally
every tunnel borer is given a female name and every Tideway drill is named after a female pioneer.

The Greenwich drill is a tribute to Annie Maunder, the first female astronomer at Greenwich Observatory.

The first digger, now headed to Fulham, is named ‘Millicent’ after
suffragist Dame Millicent Fawcett.

The machine beneath Wandsworth also takes its name from a suffragist,
Charlotte Despard.

‘Millicent’ began digging from near Battersea power station, in a shaft as wide as the dome of St Paul’s Cathedral.

However, this is still not large enough to fit all of the massive tunnel drill.

Another machine named ‘Audrey’ began digging here in late March.

This was named after Audrey ‘Ursula’ Smith, a cryobiologist at King’s
College Hospital.

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