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Work underway at Wallasea Island to receive excavated material from Crossrail tunnels next year

Thursday 29th September 2011

By Peter MacLennan

• Excavated material will be used to create new 1,500 acre RSPB nature reserve at Wallasea Island in Essex

• Jetty construction underway at Wallasea Island to enable ships to transport excavated material to Essex

Work is now underway at Wallasea Island in Essex to prepare for the arrival of excavated material from Crossrail tunnels next year. Crossrail has begun constructing a new jetty where ships will offload material for the nature reserve.

Tunnelling for Crossrail will produce in the region of 6 million tonnes of material which will be excavated from constructing the 21km of twin-bore tunnel. Close to 100% of the excavated material is expected to be clean, uncontaminated and reusable elsewhere.

The Royal Society for the Protection of Birds (RSPB) will require 10 million tonnes of excavated material to create a new 1,500 acre nature reserve - one of the largest new wetland nature reserves in Europe for some 50 years.

Crossrail will provide close to 4.5 million tonnes of excavated material to the RSPB. The remainder of Crossrail’s excavated material will be beneficially reused elsewhere.

Wallasea Island Wild Coast project is a landmark conservation and engineering scheme for the 21st century, on a scale never before attempted in the UK and the largest of its type in Europe. The aim of this project is to combat the threats from climate change and coastal flooding by recreating the ancient wetland landscape of mudflats and saltmarsh, lagoons and pasture. It will also help to compensate for the loss of such tidal habitats elsewhere in England.

The new jetty is due to be completed by summer 2012. The works are being undertaken by BAM Nuttall.

The jetty is sized to take two ships of approximately 2,500 tonnes at the same time.  At peak, it is expected that five ships per day will be arriving at Wallasea.  The Crouch Harbour Authority have agreed the works and, with support and assistance from Crossrail, has carried out major improvements to the buoyage of the River Crouch approach channels from Whitaker Spit inwards to Burnham Fairway.

Crossrail tunnelling will commence at Royal Oak in spring 2012 with the first ships containing the excavated material arriving at Wallasea Island during summer 2012.

Excavated material generated from the tunnelling operations for the western tunnels (Royal Oak to Farringdon) will exit at the Royal Oak Portal and be transported by freight train to Northfleet, Kent.

The Northfleet site will receive all the excavated material from Crossrail’s western tunnels. The primary purpose of the site is to receive excavated material by rail and briefly store it before loading it onto ships for delivery to Wallasea.

Northfleet has been chosen because it is located on the River Thames with deep water wharfage and disused links to the National Rail network, offering Crossrail the ability to transport excavated material from the new tunnels by rail and then transfer onto ship.

Reinstatement of the freight rail link into the Northfleet site from the North Kent Line is now underway and will be commissioned in January 2012. The length of the rail link is around 2.25km and in total 4.75km of new track will be provided.

Andy Mitchell, Crossrail Programme Director said: “Crossrail is committed to delivering the new railway in the most sustainable way possible. At least two-thirds of all Crossrail excavated material will be used to create a huge new RSPB wildlife reserve at Wallasea Island in Essex with the remainder destined for other regeneration sites.

“All of the excavated material from Crossrail’s western tunnels will be transported to Wallasea Island by freight train and ship to minimise the number of Crossrail lorries in central London.  Work is underway to construct the new jetty at Wallasea Island ahead of the first delivery of excavated material next summer.”

Shaun Thomas, RSPB Director of Operations said: “The RSPB is delighted to be working with Crossrail at Wallasea Island. This excavated material will help create new coastal habitats where some of the UK’s most incredible wildlife will thrive.  And it’s not just wildlife that will benefit from this partnership, the local communities, families, tourists and nature lovers will be able to visit and enjoy Wallasea Island for generations to come.”

C300 western running tunnels contractor BFK (BAM/Ferrovial/Kier JV) will shortly appoint a rail freight operator to transport excavated material from Royal Oak to Northfleet.

Freight trains will travel from Westbourne Park to Northfleet via the Great Western Main Line, the Greenford Loop, West London Line, Clapham and Lewisham. Up to five freight trains will operate from Westbourne Park on Mondays to Saturdays with up to four trains on Sundays. To enable these freight trains to operate, additional sidings will be constructed at Westbourne Park with improvement work undertaken to track and embankments on the Greenford Loop.

Excavated material from the eastern tunnels (running from Limmo Peninsula to Farringdon) will emerge from the Limmo shaft. This material will be transported via conveyor belts to Instone Wharf for direct loading onto ships and onward transportation to Wallasea Island.

For the Thames Tunnel which will be constructed between Plumstead and North Woolwich, the excavated slurry material will emerge at the Plumstead Portal, where it will be filter pressed to reduce its water content before transportation for reuse.

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Ends

Notes to Editors

Wallasea Island is located eight miles north of Southend-on-Sea.

The contract (C806) to construct the jetty at Wallasea Island was awarded to BAM Nuttall.

The C807 Marine Transportation contract to transport excavated material from Northfleet, Kent to Wallasea Island, Essex will be awarded by early 2012.

Tunnels and construction schedule:

The five tunnels to be constructed are:

• Royal Oak to Farringdon west (Drive X) - length of drive approximately 6.1 km
• Limmo Peninsula in the Royal Docks to Farringdon east (Drive Y) - length of drive approximately 8.3 km
• Pudding Mill Lane to Stepney Green (Drive Z) - length of drive approximately 2.7 km
• Limmo Peninsula in the Royal Docks to Victoria Dock Portal (Drive G) - length of drive approximately 0.9 km
• Plumstead to North Woolwich (Drive H) - length of drive approximately 2.6 km

All of this adds up to 42km of bored tunnels located below the busy streets of London.

Crossrail’s tunnel boring machines will be employed as follows:

• Royal Oak to Farringdon (Drive X) – 2 x earth pressure balanced TBMs
•  Limmo to Farringdon (Drive Y) – 2 x earth pressure balanced TBMs
• Plumstead to North Woolwich (Drive H) – 2 x slurry TBMs
• Pudding Mill Lane to Stepney Green (Drive Z) – 2 x earth pressure balance TBMs

Five tunnel portals will be constructed as part of Crossrail at Royal Oak, Pudding Mill Lane, North Woolwich, Victoria Dock and Plumstead.

The main Western and Eastern running tunnels will have tunnel portals at Royal Oak, Pudding Mill Lane and Victoria Dock. The tunnel boring machines (TBMs) will commence their eastbound journey under London from Royal Oak and westbound from the Royal Docks. 

To deliver Crossrail services to Abbey Wood, a tunnel will be constructed between North Woolwich and Plumstead – the Thames Tunnel. Tunnel portals will be constructed at either end in advance of the main tunnelling works.