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Boston Flood Barrier

In 2013, a tidal surge in the River Witham flooded over 820 homes and businesses in Boston. The Boston tidal barrier is a £100m scheme designed to control water levels and to prevent a flood recurrence. Eadon were central to the design and testing of the 362 tonne gate.

Key facts

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Location

The River Witham (known as The Haven) Boston, Lincolnshire.

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Client

Environment Agency

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In Partnership with

BMMJV

The Boston tidal barrier is part of a wider development project including flood defence walls on both banks of the Haven (River Witham) and new quay walls for the port. The barrier itself not only protects 14,000 homes and 800 businesses from flooding and from rising sea levels, it also supports water management levels between the River Witham and the Black Sluice Navigation to create a better experience for river users.

When not in use the flood barrier sits flat in a recess within the riverbed, with the hydraulic rams positioned on dry land and connected via a linkage on the pivots. These linkages also allow the gate to be manoeuvred into a position of 180 degrees so that they are out of the water, allowing access for maintenance work.

The steel gate is 28m wide, 11.5m high and weighs 362t. It is operated from a newly built control room and, when the gate mechanism is activated, it is rotated into position within 20 minutes by two 55t hydraulic rams.

Eadon’s role was multi-faceted, providing specialist consultancy to Mott MacDonald and Bam Nuttall who worked together as BMMJV on the project. Eadon provided technical expertise for the gate design and MEICA, ensuring that the build was compliant with the specification. Once the design was finalised, we provided an independent Category III design check to ensure the barrier would perform as intended in the case of a storm or tidal surge. We were also responsible for assessing safety for the whole site to the Machinery Directive so that the mandatory CE Mark could be issued.

The project has provided the community of Boston with one of the best standards of flood protection outside of London, and has since won the ICE award for sustainability in engineering.