Cintra Global of Spain, wholly owned by Spanish construction group Ferrovial, is selected by Transport for London (TfL) as the preferred bidder to the 30-year concession to finance, design, build, own, operate and maintain the £1 billion Silvertown highway tunnel under the River Thames in London. Within the selected group’s proposal, the Riverlinx JV comprised of Ferrovial, BAM Nuttall and SK Engineering of South Korea will undertake construction of the tunnel. Announcement of the one preferred bidder beats the rival Hochtief PPP Solutions group.

Fig 1. Silvertown under river link will augment capacity of the existing Blackwall tunnel to the west

Reference design for the 1.4km long twin TBM-bored tunnel under the river was completed by a group led by Atkins, and Cintra has engaged designers COWI and Arup to complete the design-build detailed design for River Link JV. One TBM of about 11.5m diameter is expected to be procured by the JV to excavate the 1.2km TBM drives between cut-and-cover approach ramps in Greenwich and Silvertown (Fig 1). The two two-lane bores will be connected with a set of cross passages.

The project is being sponsored by Transport for London (TfL), which is under the purview of the Mayor of London administration. It is designed as 30-year concession with the concessionaire Cintra being paid a lane rental payment on a lane availability basis. Electronic tolls will be paid by users of the new river link.

With selection of the preferred bidder, following final planning approval by UK Government in May 2018, the next step in project development is for the consortium, which includes Aberdeen Standard Investments and Macquarie Capital, to finalise the financing of the project over the coming months. TfL said in a statement it will only award the contract upon completion of financing details. During that time the consortium will also be setting up the supply chain for the works.

In its announcement, TfL also announced a planned opening of the new road link in 2025 when previous project information, during the planning and procurement phase, discussed an earliest opening date of 2024.

The new crossing will ease chronic peak traffic congestion at the existing Blackwall road tunnel crossing to the west and also at the Dartford bridge and tunnel crossing on the M25 London orbital motorway down river to the east. Challenges for the tunnel constructors will include the potential for undiscovered ordinance in an historically heavily bombed part of London during WWII, contamination of the ground in what was an industrially developed part of the city and location of a hazardous material factory close to the south portal of the project. The area of the project is also influenced by the addition of more recent infrastructure including the Docklands Light Railway (DLR) and its Woolwich branch viaduct, and the Emirates Air Line cable car link across the river on approximately the same route as the new tunnel.

Despite ongoing debate over the handling of hazardous materials near its south portal, the UK Government met its 10 May deadline and has given consent for construction of the 1.4km long, twin-tube Silvertown road tunnel under the River Thames in south east London.

New Silvertown road underpass of the Thames in London approved

In its decision letter, the Department for Transport acknowledges the disagreement over hazardous materials consents at neighbouring industrial sites could delay completion of the scheme but expressed hope, given the length of the construction period, that the differences can be overcome during the project period.

Developer of the new road crossing, Transport for London (TfL), has stated that the unresolved question presents a continued challenge. Earlier in 2018 the TfL lawyers told the Department for Transport that TfL would not be in a position to award the contract should there be risk the tunnel might not open.

TfL is procuring the project on a design, build, finance and maintain (DBFM) model that will include development and funding risk. In March 2017 three groups were shortlisted to progress to the request for proposals (RFP) stage. Since then, Strabag has been awarded the first of three major tunnel contracts for development of the Woodsmith potash mine materials transportation handling tunnel in north east of the UK and has withdrawn from its Silvertown shortlisted group with Skanska and lead designer CH2M. This leaves the Cintra Global Ferrovial Group of Spain and the group lead by Hochtief PPP Solutions of Germany to vie for the project.

The nub of the debate at Silvertown is between TfL and the Health & Safety Executive (HSE) over managing hazardous materials consents at the Brenntag Inorganic Chemicals Ltd industrial site and the Greenwich Gasholder Station near the approach road to the south portal of the tunnel.

UK Planning Inspectorate assessed the TfL application for the development consent order (DCO) for the Silvertown Tunnel during June 2016 to April 2017, and gave its green light to the project in mid-2017. The Inspectorate’s assessment panel believe the issues would not necessarily prevent the Government from granting consent but did caution the Department for Transport which stated in its DCO approval letter that “a situation could arise where the development could not be opened for use or could be delayed due to compensation issues on the adjoining sites”.

The Government believes the differences are fixable and that there is time to do so and in time to meet the TfL stated project completion date of 2022-23.

The earlier schedule for planning assessment of the Silvertown Tunnel expected the approval process to conclude by late 2017, allowing time for contract award and construction start by mid-2018. But extra time was then needed to study new air quality rules. Within these months, the differences between TfL and HSE on how best to resolve their differences on handling the hazardous materials consents at the neighbouring industrial sites remains unresolved.

In granting the DCO, the Department for Transport says any legal challenges to its approval have six weeks to be lodged with the High Court.