Crossrail has taken another step towards the creation of a new 1,500 acre RSPB nature reserve with the completion of a new 180 metre jetty at Wallasea Island in Essex. The jetty will receive in the order of 4.5 million tonnes of material excavated during Crossrail’s tunnelling operations in London.
Wallasea Island Wild Coast project is a landmark conservation and engineering scheme, 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 jetty, constructed by BAM Nuttall, comprises two 800 tonne steel pontoons, each 15 metres wide, and is able to accommodate two 90 metre, 2,500 tonne ships simultaneously. At peak, two unloading machines per pontoon will service four ships and unload up to 10,000 tonnes of material over a 24 hour period.
An 800 metre conveyor system to transport the material within the site has also been completed. The conveyor stretches from the jetty to a holding point for the excavated material, from which the material will be distributed around the site by truck.
Excavated material will be unloaded directly from the ship on to the conveyor system. To accommodate tidal movements of up to six metres, the conveyor comprises a flexible section on the pontoon connecting to a fixed shore section.
The RSPB nature reserve will be one of the largest new wetland nature habitats in Europe, providing an environment specifically tailored for fish, reptiles, insects, mammals and birds and acting as a tourist attraction and recreational resource for local people.
Siobán Wall, Crossrail’s Wallasea Project Manager said: “Construction of the Crossrail jetty at Wallasea Island is now complete and ready to receive the first shipments of excavated material later this summer. This is an important milestone in the use of rail and ship to sustainably transport excavated material from London to create a new RSPB nature reserve.”
Excavated material from Crossrail’s western tunnels will be transported by freight train to Northfleet where it will be transferred to ship for onward journey to Wallasea Island. The first trainload of material ran from Westbourne Park in May; at the peak of tunnelling up to five freight trains a day will operate. The first of over 2,000 ship loads to Wallasea Island will arrive later this summer.
Elsewhere along the Crossrail route, the first consignment of excavated material from the construction of Liverpool Street station into Crossrail’s new Docklands Transfer Site at Barking Riverside jetty occurred on 1 June. Excavated material from Crossrail’s station and shaft works will also be shipped to Wallasea from this site.
Shipments of excavated material from the eastern running tunnels access shafts at Limmo Peninsula to Wallasea will commence from Instone Wharf (directly opposite Greenwich Peninsula and the 02) following dredging operations and the construction of a new ship loading facility.