London Gateway, the megaterminal P&O is planning to build at Corringham, 'will re-establish the Thames as a major port', boasts P&O chief port engineer Tony Burdall.
Designed to handle a phenomenal 3.5M TEU a year, the container port will be visited by 1,700 of the world's biggest ships, increasing traffic on the Thames by close to 15%.
Tankers have been going to the Corringham site, home to a Shell refinery now being demolished, for over a century. Getting large vessels up the Thames' narrow navigation channel poses no major new challenges, Burdall says. But while London Gateway's UK competitors Felixstowe and Southampton have already dredged down to 14.5m and 12.5m respectively, channel depth in the Thames is in places as little as 10.1m. Nearly half of the 90km long deep water channel, from The Sunk via Black Deep, Knock John, Oaze Deep and Yantlet to the terminal, will need to be dredged.
In the outer reaches of the channel, depth will be increased to a minimum 16.5m, with 14.5m over the remainder. Extensive navigation modelling has been carried out by research house HR Wallingford to help minimise the extent - and hence cost and environmental impact - of the dredge.
The sea bed is a mix sands, gravels and silts with some London Clay. Trailing section hopper dredgers will be used for most of the job, with grab or bucket dredgers used to excavate the clay, which will be reclaimed for use in lining and capping landfill sites.
By UK standards the dredging campaign will be impressive:
Some 30Mm 3of material will be pumped ashore as part of a major 93ha land reclamation at the London Gateway site. P&O is acquiring a total of 607ha from former site owner Shell. Of this 140ha is being set aside as green space - it is home to a 'Noah's Ark' of animal, bird and plant life, says Burdall. Close to 400ha is earmarked for a giant industrial and commercial park that will provide in the region of 930,000m 2of space.
That leaves 75ha of the existing site for the terminal development. Two jetties which currently project into the river will be demolished, but they mark the future line of the quay wall. The reclamation will take place in two phases, the first getting under way in late 2003 or early 2004, starting at the east of the site and progressing west.
Burdall and P&O's engineering consultant Halcrow are undecided on whether to use a piled combi wall or open framework structure for the quay. The 3km long structure will provide 2,300m of berthing for container vessels, to be served by 27 ship to shore gantry cranes, and facilities for two ro-ro ships at the eastern end. Quayside water depth will be 16m. While Burdall is not expecting ships to get much longer, the scheme is being designed to handle ships up to 24 containers wide - the biggest ships afloat today are 22 containers wide.
According to Royal Haskoning environment director Sian John, the reduced river width brought about by the land reclamation will be compensated for by increased dredge depth. To prevent sediments accumulating in the deep water berthing pocket Burdall is considering laying sea bed pipes that will 'blow' fines back into suspension.
Main environmental impacts will be during construction phase, claims John: Noise and vibration caused by piling, and reduced water purity caused by dredging, are cause for concern among local residents and fishermen. Meanwhile, although there will be some erosion towards the centre of the Mucking mudflats upstream of the development, hydraulic modelling shows that accretion will take place at the ends of the flats, leading to the formation over time of salt marsh.
Post construction, public attention is focusing on road and rail links into the site. Unlike Southampton and Felixstowe, where the bulk of container movements are a result of transhipment, 90% of containers passing through London Gateway will be for import or export.
In all, 30% of the annual total of 3.5M containers will arrive at or leave the terminal by rail and 60% by road.
P&O is planning to realign and double the Thames Haven branch line, pulling it away from nearby houses and linking it to the neighbouring refinery at BP Corrington. The port operator plans to build a high speed container terminal, with a separate siding into the ro-ro terminal. All the warehouses in the vast hinterland behind the terminal will be connected to rail as well.
'That's one hell of a commitment to railways, ' comments Burdall.
Road widening and strengthening is already under way in the area, but further upgrades will involve relocating the roundabout that connects the A13 with The Manorway - a major road wrapped around the site to the north. Earth bunds and planting will be provided as an acoustic buffer between the major traffic arteries and local housing.
A public inquiry is scheduled for later this year, says Burdall.
P&O hopes it may get planning consent by the end of 2003.
Dredging, reclamation, quay construction, fit-out, and road and rail improvements will cost £660M. P&O has not yet declared the cost of developing the industrial/ commercial site. Over 20 years since Tory minister Michael Heseltine launched the idea of regenerating the Thames corridor, P&O is holding out the promise of 16,500 jobs in what will be the UK's largest container terminal.
The UK's busiest container port Felixstowe has grown apace in the last 10 years and is pushing to extend its newest 2km long quay at Trinity terminal by an extra 270m.
Felixstowe's owner and operator Hutchison Ports UK has far greater ambitions, however, for a new 1,400m quay at Bathside Bay next to the port of Harwich.
The Government has approved the scheme in principle by passing the Harwich & Parkstone Quay Act but it is likely a public inquiry will be called to scrutinise plans more closely. If all goes smoothly Hutchison Ports hopes to have half the terminal built within 15 months, to be up and running by the close of 2004.
The Bathside Bay development would be able to handle 1.7M TEU a year, with 11 ship to shore gantry cranes, 40 rubber tyred gantries and a rail terminal capable of shifting 300,000 TEU from ship to train. Hutchison Ports is talking to the Strategic Rail Authority about upgrading the Felixstowe-Nuneaton line, where trains would join the West Coast Main Line. Total project cost, including cranes, is expected to be £300M.