Boston Barrier Scheme

Year:2018

Duration:3 years

Cost:£120 million Flood Defence Grant in Aid

Country: Lincolnshire, England

What did this project achieve?

People

One of the best standards of tidal flood defence in the UK

The Boston Barrier in Boston, Lincolnshire, is one of the biggest civil engineering projects the town has ever seen, with over £100 million Flood Defence Grant in Aid invested to better protect over 14,000 properties from tidal flooding. Once complete, it will provide one of the best standards of tidal flood defence in the UK outside London.

The project is innovative in its design, construction and implementation, and through seamless collaboration by many parties, is setting a new benchmark for flood defence construction. It’s a true demonstration of how the impact of a natural disaster can be assessed and responded to in a way that transforms an entire community, safeguarding the long-term future of generations to come in Boston.

The team working on the barrier have used United Nations Sustainable Development Goals (SDGs) as a basis for monitoring and evaluating success, incorporating them where it would help improve the project. This has maximised the project’s benefits by supporting and ensuring great outcomes for the local community of Boston.

The main component of the scheme, a 300 tonne, 25m-wide rising sector gate, was delivered to site in November 2019 and became fully operational in December 2020.

Along with the primary barrier gate, miles of steel sheet piles have been installed to reinforce embankments and create floodwalls on both sides of the river. A control building for the operation and maintenance of the barrier has been built and replacement vertical sector gates for the Port of Boston wet dock entrance will be installed in 2021 to better protect Boston town from the threat of tidal flooding.

The Boston Barrier is one of the biggest civil engineering projects the town has ever seen, with over £100 million Flood Defence Grant in Aid invested to better protect over 14,000 properties from tidal flooding. Once complete, it will provide one of the best standards of tidal flood defence in the UK outside of London.

The project is innovative in its design, construction and implementation, and through seamless collaboration by many parties, is setting a new benchmark for flood defence construction. It’s a true demonstration of how the impact of a natural disaster can be assessed and responded to in a way that transforms an entire community, safeguarding the long term future of generations to come in Boston.

By using United Nations Sustainable Development Goals as a basis for monitoring and evaluating success, the team provides a holistic approach to project planning and management and maximises the project’s benefits. By working through all UNSDG goals and sub-goals the team determined how the project can be improved by incorporating them. This has maximised the project’s benefits by supporting and ensuring great outcomes for the local community of Boston.

Boston is an historic market town with an important maritime history, but it is unfortunate to lie entirely within a floodplain. The town has been devastated by flooding many times over the years and in the past 200 years has experienced nine major tidal floods. The most recent tidal surge, in December 2013, flooded over 800 properties across 55 streets, leading to significant economic, social and environmental damage.

The Government announced that the Boston Barrier was deemed a national priority project in the 2014 Autumn Statement. Two years later, in 2016, the outline business case for the scheme was approved by the Treasury.

BAM Nuttall Mott MacDonald Joint Venture won the contract and began work on site in January 2018. The main component of the scheme, a 300 tonne 25m wide rising sector gate, was delivered to site in November 2019 and became fully operational in December 2020.

Along with the primary barrier gate, miles of steel sheet piles have been installed to reinforce embankments and create floodwalls on both sides of the river. A control building for the operation and maintenance of the barrier has been built and replacement vertical sector gates for the Port of Boston wet dock entrance will be installed in 2021 to better protect Boston town from the threat of tidal flooding over the next century.

Once the £100m scheme is fully completed in 2022, over 14,000 homes and 800 businesses will be better protected against tidal flooding, including allowing for the effects of climate change, for the next 100 years.

Maximising the benefits of the scheme to society was a fundamental focus for all partners which included the Environment Agency, Lincolnshire County Council, Boston Borough Council and Black Sluice Internal Drainage Board.

The project is more than just a flood defence and it has been estimated that the scheme could help to deliver over £1 billion in economic benefits to Boston town and the surrounding area by encouraging investment, improving resilience and well-being, and by protecting historic assets.

The construction team made it a priority to spend locally where they could and have invested over £7 million in the local economy within a 50 mile radius of the site to date (April 2021).

The scheme also includes works to tie the project into the Haven Banks Improvement Scheme – a separate Environment Agency project downstream of the barrier site which raises and strengthens 5km of existing flood banks on each side from the primary barrier towards the Wash.

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The Boston Barrier project has been an outstanding project to lead following the devastation which occurred in Boston on the 5 December 2013. Being a duty officer responding to the tidal surge as events unfolded, to leading the solution to better protect people and the environment in and around Boston is a great privilege. Not only will we better protect over 14,000 properties, but we are also providing Boston with one of the best levels of protection outside of London. Our work allows for the forecast climate change over the next 100 years and demonstrates how we can respond as civil engineers providing climate adaption projects that not only provide protection but that can also support and enhance local communities now and into the future.

Adam Robinson,
Environment Agency Project Director

Project Milestones

  • 2014 – Barrier announced as a UK government national priority project
  • 2016 – Funding approved by UK Treasury
  • 2018 – Work begins on site
  • 2019 – Primary barrier gate delivered from Holland by boat
  • 2020 – Primary barrier officially opened and 13,731 homes better protected
  • 2021 – Secondary barrier arriving from Holland ready to install
  • 2022 – Project to complete and better protect 14,300 homes from North Sea tidal surges for the next 100 years

What engineering skills we used in the project?

  • Civil engineering
  • Mechanical and electrical engineering (MEICA)
  • Geotechnical/Ground Engineering
  • Project management and site management
  • Environmental including carbon offset and mitigation
  • Design – BIM, federated models, 3D and virtual design
  • Construction skills – concrete, steelwork, reinforcement, precast and prefabrication
  • Site development and spatial planning for confined sites and shared spaces
  • Structural steel design – primary gates, structural gates, building design, sheet piled walls
  • Hydraulic high pressure design and fabrication in stainless steel

Fascinating facts

The primary barrier gate which was completed in December 2020, can be raised in just 20 minutes, responding quickly to threats of North Sea tidal surges.

The gate is so big it had to be shipped across the North Sea on a barge and driven into place over a temporary bridge by self-propelled modular transporters – no cranes were involved.

The primary barrier gate weighs over 750 tonnes when ballasted – the equivalent of 180 elephants!

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