Tunnelling for Crossrail will produce in the region of 6m tonnes of excavated material. Some 4.5m tonnes is being supplied to the Royal Society for the Protection of Birds (RSPB), which is planning to recreate a wetland landscape at Wallasea Island and help compensate for the loss of similar tidal habitats elsewhere in England due to rising sea levels.
The excavated material will be used to raise existing land levels and also create raised areas within the existing island sea walls. These walls will later be opened up at certain locations to allow tidal water to flow in and out of the island, creating natural wetlands over time. The contractor will also be responsible for creating tidal structures within Wallasea Island to enable water levels to be precisely managed in certain areas.
The Bam Nuttall/Van Oord JV saw off competition from five other shortlisted bidders:
- Carillion Capital Projects;
- Cemex / Keltbray JV
- Lagan Construction
- Port of Sheerness
Crossrail programme director Andy Mitchell said: “We are delighted to be working in partnership with RSPB to create a major new nature reserve that can be enjoyed for generations to come. At least two-thirds of all Crossrail excavated material will be used to create the wetland at Wallasea Island. With the award of the contract to transport excavated material, Crossrail has now awarded the last remaining major contract that will allow tunnelling to commence in spring 2012.”
Crossrail tunnelling will start at Royal Oak in March with the first ships containing the excavated material arriving at Wallasea Island during summer 2012. The contractor will be responsible for shipping excavated material from Instone Wharf and Barking Riverside in east London and Northfleet, Kent to Wallasea Island.
Up to five ships a day will transport excavated material down the River Thames to Southend–on-Sea. They will then travel north passing Foulness Island before turning west into the River Crouch to reach Wallasea Island.
Contract C806 to construct the jetty at Wallasea Island was previously awarded to Bam Nuttall and construction is underway. The jetty is sized to take two ships of approximately 2,500 tonnes at the same time.