factsheetHow we construct a tunnel

For all our construction projects, we are committed to minimising the effect on local communities and the environment. We are looking at building the pipeline in a new tunnel beneath the River Humber between the existing above ground installations (AGIs) near to Paull, on the north bank and Goxhill, on the south bank.

The preferred route corridor for the pipeline is 6km long, of which 5km would be tunnelled. A short distance of onshore pipeline would be required on either side of the river in order to connect to the existing AGIs.

There will be further consultation with local communities in future on the precise route of the pipeline and detail of the construction process in 2014.

Protecting the environment

We recognise the international importance of the River Humber as an environmental conservation area and will work to ensure any potential environmental effects are avoided or minimised.

Ecology, archaeology, and other environmental factors are important considerations when planning a pipeline route and great care has been taken to consider these issues in the design of this project.

A new pipeline beneath the River Humber presents the least potential for disruption to the local environment, resulting in fewer overall impacts when compared with much longer alternative options that avoid the River Humber.

We have worked closely with a number of stakeholders, including the Environment Agency, Natural England and Associated British Ports (the Harbour Authority for the River Humber) to minimise any effects on the marine environment and commercial and leisure users of the river. We will continue to engage with local communities and stakeholders as we progress our plans.

Minimising the effect on the River Humber and its users

Our plans are still at an early stage. The comments we receive from local communities and other stakeholders will be considered as we progress our plans and there will be further consultation on the project in the future. All of our contact details can be found on the back page.

Have your say

We will work closely with local communities and other stakeholders as we progress our proposals to ensure the environment is protected. For example, specialists will be employed to carry out detailed studies of the local ecology as part of the process to determine the precise route of the new pipeline.

Were the project to be granted consent, appropriate mitigation would be implemented to ensure potential effects are avoided or minimised. This would include considerate design and careful restoration of landscape and habitats following construction.

For further information about the project, please visit www.nationalgrid.com/riverhumberpipeline

Shaft construction

Shafts typically up to 30 metres deep are built on either side of the river.

These can be vertical or sloped, depending on geological and engineering considerations.

Tunnel boring

A tunnel bore machine digs the tunnel beneath the river.

This can bore through anything from hard rock to sand.

A decision as to which side of the river construction would commence will be made at a later stage.

Concrete lining

The tunnel is lined with concrete segments as it is dug.

The excavated material is transported for use or disposal away from the site. We are investigating options for its reuse.

String fabrication and pipeline pulling

The pipeline is pulled through the tunnel from the surface in ‘strings’ – long, welded sections of pipe assembled on-site on one side of the river.

Once complete, the tunnel shafts are filled and the land reinstated as close to its original condition as practical.

How we construct a tunnel

At a later stage of this project, we will carry out further detailed ‘on the ground’ environmental studies and assessment. This will assess a wide range of environmental issues including ecology, archaeology, noise and vibration, water resources and landscape and visual aspects. This will be considered as part of any future planning application.

Environmental assessment

Preparation of the working width

Pegging out centre line

Fencing off working width

Securing public rights of way

Pre-construction drainage

River bridging/fluming

Top soil stripping and storage

Clearing field boundaries

Boundary fences

Stored topsoil

Working width

Pipe section

Pipe support

Running track

Head layer storage

Subsoil storage

Backfilling and reinstatement

Grade subsoil to match original contours

Post-construction drainage

Topsoil replaced

Field boundaries replaced

Boundary fences

Stored topsoil

Working width

Pipe section

Pipe support

Running track

Head layer storage

Subsoil storage

Pipelaying

Welded sections of pipe are lowered into trench

Original subsoil replaced in trench

Replace head layer

Boundary fences

Stored topsoil

Working width

Pipe section

Pipe support

Running track

Head layer storage

Subsoil storage Trench excavation

Trench digging

Head layer storage

Subsoil storage

Drains cut and marked for later reinstatement

Boundary fences

Stored topsoil

Working width

Pipe section

Pipe support

Running track

Head layer storage

Subsoil storage

Boundary fences

Stored topsoil

Working width

Pipe section

Pipe support

Running track

Head layer storage

Subsoil storage

Pipe delivery, stringing, bending, welding, testing and coating

Pipe delivery and movement down pipeline spread

Placement on supports

Welding

Protective coating

How we construct a pipeline

Information about the project can be found on our website and there are a number of ways you can contact us.

Online: www.nationalgrid.com/riverhumberpipeline

Email: nationalgrid@riverhumberpipeline.com

For consultation information only call freephone 0800 988 9144Lines are open 9.00am – 5.00pmMonday – Friday

Write to: FREEPOST NATIONAL GRID R H PIPELINE PROJECT

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How to contact us