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In recent months we have covered Crossrail Tunneling and Tunnel Boring Machines (TBMs) quite extensively. One part of the process we haven’t really looked at in depth, however, is where the excavated material ultimately ends up.

This may seem a rather strange topic to cover, but like all mega-projects Crossrail’s impact extends well beyond the range of the area it’ll ultimately serve. Tunneling and construction will see Crossrail generate approximately 6.5m tonnes of spoil which, as anyone who has ever watched the Great Escape knows, needs to go somewhere.

In Crossrail’s case, the bulk of this spoil is clean and can be reused. On most projects, it would thus be dispersed over a number of sites, but interestingly in Crossrail’s case much of this excavated material (4.5m tonnes of it) is actually destined for one single place – Wallasea Island on the Essex coast.

Wallasea Island, via Google Maps

Wallasea Island, via Google Maps

Bounded to the north by the River Crouch and to the south by the River Roach and Paglesham Pool, Wallasea was mostly wetland mud flats until the arrival of Dutch settlers in the area. Flat and low lying, the construction of sea walls allowed it to be turned into farmland and it saw cultivation until the 19th Century, when periodic flooding and crashing wheat prices saw the island’s population decline. Brief agricultural resurgences during both World Wars followed, but the floods of 1953 marked something of a point of no return.

Wallasea From the Air

Wallasea from the air

This photo gives an idea as to just how flat Wallasea is

From on top of the sea wall, this gives an idea as to just how flat Wallasea is

Since 1953 Wallasea has led a rather unremarkable existence. In 2006, however, the RSPB decided to embark on an ambitious scheme -the Wallasea Wetlands project. This involved taking over 115 hectares of Wallasea farmland and demolishing the surrounding sea wall. With their section of the island now flooding again at high tide, the original salt marsh and mud flats began to return, and with them the birds and other wildlife that had once been a regular feature of the Essex coast.

The Mudflats Returning to Wallasea

The mudflats returning to Wallasea

The RSPB’s project was a success, and with the need for mudflats and marshes growing (it is now often an EU requirement that endangered environments removed through the construction of ports and other coastal sites be replaced elsewhere), the decision was taken to embark on one of the largest and most ambitious Conservation projects yet seen in the UK – the whole of Wallesea would be taken over and turned into the largest wetlands conservation site in Europe.

Wallasea Island 2019

Wallasea Island 2019

Recreating 1,500 acres of ancient mudflats and saltmarsh, lagoons and pasture on Wallasea requires significant landscaping. The extensive walkways and new sea walls required to make the site accessible to visitors (and to keep differing environments separated) will require approximately 10 million tonnes of earth.

With Crossrail thus looking to dispose of 4.5m tonnes of clean spoil, and the RSPB looking to find 10m tonnes of it, a partnership seemed like a very good idea indeed.

Moving the Earth

As anyone involved in the process of spoil disposal and management will tell you, finding somewhere to put your excavated material is only half the battle. The other half is working out how the hell you get it there.

As we’ve highlighted before, in Crossrail’s case, this largely means moving spoil by rail (although early on there were some rather creative ideas about reusing the old Post Office Railway and the Kingsway Tunnel to do some of the job). All spoil from the Western Portal is taken via the Great Western Main Line, the Greenford Loop, West London Line, Clapham and Lewisham down to Northfleet, where the reinstatement of the freight rail link from the North Kent Line means access can be gained to Lafarge’s new railfreight depot at Northfleet, on the site of the old Concrete Works.

Heading into Northfleet

Heading into Northfleet

Looking Out Over Northfleet

Looking out over Northfleet

Northfleet feels a lot like old Docklands

Northfleet feels a lot like Docklands in the eighties

Spoil from the eastern portal has a slightly easier journey to the river – once tunneling begins it will be transported via conveyor belts to Instone Wharf.

In both cases, the spoil is then transferred to barges and taken to Wallasea.

The End of the Line

Due to the already protected nature of Wallasea’s environment, Crossrail’s actual presence on the island itself can be described minimalist at best, which presents a rather interesting contrast with the amount of material being brought in. A large jetty has been constructed by BAM Nuttall just offshore, to which the spoil can be delivered and conveyed inland.

Standing alone and kept to the absolute minimum amount of ground occupation necessary, the jetty is a surprisingly striking structure – and one that’s deceptively large.

Approaching the Jetty from the Water

Approaching the Jetty from the Water

The jetty close up

The jetty close up

Looking along the jetty

Looking along the jetty

The jetty superstructure

The jetty superstructure

Looking back along the jetty

Looking back along the jetty

The huge machinery onboard hints at the sheer amount of material that will pass through the jetty, as do the conveyors, which run up from both sides (to allow two ships to dock at once) and over the top onto the island itself.

Lifting machinery sits on both ends of the jetty

Lifting machinery sits on both ends of the jetty

Conveyor on the Jetty

Conveyor on the Jetty

The conveyor link from the top of the superstructure

The conveyor link from the top of the superstructure

Inside the conveyor bridge

Inside the conveyor bridge

Like much of the Crossrail project, the jetty feels like an impressive piece of engineering with a large task ahead. The view inland, however, manages somehow to eclipse it – and it is this image that we have saved until last. For while the engineering needed to turn this London spoil instead into a little bit of Essex is huge, nature is bigger…

Into the distance

Into the distance

…And the sight of the vast conveyor stretching off into the flatlands of Wallasea makes this large jetty actually feel like a very small and lonely outpost of technology indeed.

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There are 26 comments on this article
  1. Anonymous says:

    What impact does this project have on the Thames Estuary airport proposals? Birdlife and jet engines have a notoriously fractious relationship.

  2. Anonymous says:

    The jetty reminds me of Crab Quay!

  3. Pete In The US says:

    So this is Boris Wetland???

  4. Otter says:

    Anon 06.44pm: None. Wrong estuary. Boris’ folly off map to south.

  5. Paul says:

    @Otter @Anon To be fair, Boris Island would be very much closer to Wallsea than it would be to London.

  6. Josh says:

    That is quite far North. Even if Boris Island had North-South runways, approaching aircraft would still be above 2000ft probably going over the area so not much of an issue.

  7. Greg Tingey says:

    If you really want a strange place, try the “penisula” to the North – the Dengie.
    Once past Burnham, the land goes “bumpy”, at least haf the older houses are clap-board, and especialy once beyond Southminster, errr ..
    Where does the land stop or start? Where does the sky stop or start? Where does the sea stop or start?

    Very much Ransome “Secret Water” country, though that was the next one North again ….

  8. Anon says:

    Sounds like a well thought through process, good to see mutual benefit as well.

    Does anyone else remember, before this became the definite destination, that one ambition was to use the spoil to build up bases under the proposed new houses in the Thames Gateway area, to protect them from flooding? That always sounded like quite a good idea as well.

  9. Fandroid says:

    Is Wallasea bigger than the Dutch Oostvaardersplassen where they reclaimed a chunk of the old Zuider Zee then decided not to develop it for farmland or building? There they introduced herds of grazing animals and just left things to go as nature dictated. Not enough wolves though! So the odd buffalo gets shot.

    Back in the early 2000s I commuted to/from the Netherlands and used to love the aerial approach over the Essex coast. It’s an absolutely fascinating area, and this project should make it even more interesting than it already is.

  10. Simon says:

    Fascinating post, and great pictures – thanks.

    I can’t help but wonder where they’ll get the remaining 5.5m tonnes of the stuff from. Is somebody digging an even bigger tunnel somewhere?

  11. John Bull says:

    I believe they’ve got another couple of sources already highlighted, with discussions underway as to how the Crossrail Jetty can potentially be used to support the extra spoil needs – i.e. not just be used for the Crossrail project itself.

    Not sure how far along those discussions are though.

  12. mdb says:

    > I can’t help but wonder where they’ll get the remaining 5.5m tonnes of the stuff from. Is somebody digging an even bigger tunnel somewhere?

    Perhaps the Thames Water super sewer under the river? I believe it is as big if not slightly bigger bore than a Crossrail tunnel?

  13. Mwmbwls says:

    Were I a cock eyed optimist rather than a jaundice eyed economist, I would suggest that a seamless roll over into constructing Crossrail 2 would provide not only more spoil for the RSPB but also sustain the by then experienced workforce who are currently graduating from the Tunnelling Academy and building the tunnels. As a added bonus the evacuation infrastructure for CR1 spoil trains could be easily diverted to begin at Wimbledon or Clapham. It isn’t as if a national rolling programme of using railway tunnels to re-engineer national infrastructure has not been successful before – ( in Switzerland). However there is a long standing Government view that the terms “synergy” and “railway infrastructure” together with subversive concepts such as thinking of the joined up variety must never be allowed in the same policy document. If only, say, a London Mayor were to go on to be Prime Minister and remember the lessons learnt during his time at City Hall – but then of course that could never happen.

  14. Anonymous says:

    Re Mwmbwls 08:08AM, 22nd August 2012

    “Mean while back at the Start of the Earth
    http://www.constructionenquirer.com/2012/08/22/crossrail-ramps-up-tunnelling-as-paddington-reached/

    Any idea why they are stopping the first TBM just short of the Paddington station box and waiting for the 2nd before breaking through into the station box together, I haven’t seen a good explanation yet?
    (I would have thought it was easier not to have 2 TBMs in the station box at the same time? or are they worried about movement in buildings above hence wanting to break through at the same time to minimise risk? or is the supply chain to / from the western portal restricted until both TBMs are out of the way?)

  15. Snowy says:

    Sadly I can’t see XR2 happening until after they’ve completed HS2 +/- the Y-shape to the north considering the tunneling & engineering required for that.

  16. Anonymous says:

    Mwmbwls: HS2 is due to start just as crossrail is finishing. I believe this is both for financial reasons (£x bn a year on Crossrail becomes £x bn a year on HS2) and also so that the experienced tunnellers can just hop over to the new site.

    Sods law says that HS2 will get delayed by legal wrangling just long enough to blow this plan out the water

  17. Anonymous says:

    You can’t start off two tunnel boring machines together for safety reasons as there isn’t enough clearance on site between the two for people to operate around both safely. You also can’t run two machines in close proximity due to ground settlement issues. So one goes first and then the other follows. The stretch to Paddington is vey difficult and slow as you are weaving under the Tube and National Rail on their approaches to Paddinton. Far easier after Padington as you heading On an incline below existing infrastructure so it is quicker or where infrastructure is limited. Separately, each batch of TBMs are slightly different so a crew needs to learn how the Crossrail TBMs respond, a bit like cars being different to drive even though the pedals are the same. One crew will drive the first TBM to Paddington and then start the second using the learning they have gained from the first drive. Once they get a certain distance then another crew will take over the second TBM and the first one will progress forward with the other slightly behind. All this is planned in the schedule and perfectly normal. Hope that helps.

  18. Anonymous says:

    Southend Airport is in close proximity to Wallasea Island – the flightpath for easyjet planes coming into land is over the island.

    Interestingly Alfred Hitchcock apparently got the inspiration for The Birds film following a visit to nearby Burnham-on-Crouch. http://www.guardian.co.uk/travel/2009/mar/24/essex-uk-dengie-peninsula

  19. Ian Sergeant says:

    While what is happening with Phyllis and Ada is perfectly normal, is it not also true that Phyllis cannot yet progress through Paddington Station box? I believed that there is a dependency between a certain amount of progress on the cut-and-cover box and the TBMs proceeding.

  20. Anonymous says:

    I’d heard HS2 was “effectively dead” (source, via DD’s forums). Is this just a silly rumour?

  21. Greg Tingey says:

    The Spectator is known to be currently acting as an anti-HS2 front for the 0.1% rich living in (parts of) the Chilterns – and also the air lobby, of course.

  22. Anonymous says:

    See who gets transport in the reshuffle.

  23. answer=42 says:

    @Anonymous 12:07

    The article you cite is from June and funding for HS2 continues. However, there is evidence that the green light for HS2 will not be given in the present parliament. Osborne has funded the ‘electric spine’ from Southampton to Reading, Oxford and Bedford which provides additional North-South rail freight capacity. This appears to be intended to weaken the case for HS2.

    Any objective analysis would support HS2, underlined by the self-contradictions of the Spectator article. Next time someone tells you that HS2′s cost-benefit ratio is low, explain that this measures the social rate of return, the social ‘profit’ rate if you like. Any company that tried to maximise its profit rate and not its total profits would be out of business in a trice.

    All smoke and mirrors. For once, Greg hits the nail on the head.

  24. Alan Griffiths says:

    “A fifth TBM, Sophia has recently completed factory testing. Early next year Sophia will begin constructing the 2.6km Thames Tunnel between Plumstead and North Woolwich.”

    They musn’t use that name. “The Thames Tunnel” was built by Marc and I K Brunel and there is no other.

  25. Martin says:

    My grandad built the original jetty on Wallesea and worked there for decades as the head dock master.. sure he would be amazed to see this now..

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