The Environment Agency has started work on a £15 million project to refurbish Boston’s Grand Sluice, helping to protect 9,000 homes and over 25,000 hectares of farmland from the devastating effects of flooding.
For 250 years the Grand Sluice has kept the tide out of the River Witham and managed water levels in the river from Boston to Bardney. To ensure the sluice can continue this vital work the Environment Agency is undertaking a refurbishment over the next four years.
The Grand Sluice has 2 main components, the pointing doors and the guillotine gates, which will be replaced. The pointing doors stop the tide coming in from the sea and keep the Witham upstream as freshwater. The guillotine gates control the river level upstream, keeping it safe for navigation and for water supply.
The Grand Sluice takes care of the regular tides, protecting homes and businesses from flooding, allowing navigation for boaters, and supporting water supply for homes and 126 water abstractions for farms. Downstream is the Boston Barrier which protects against extreme tidal surges.
The pointing doors.
The refurbishment will include changes to the sluice so aquatic weed can be flushed more effectively without losing as much water. Aquatic weed can block the channel and cause problems for boaters and wildlife.
This summer, stop logs will be installed to allow the safe isolation of one channel at a time for the main gate works. In 2026, one channel’s gates and doors will be replaced, with work on the second channel the following year, and the third channel after that.
Work is carried out in the summer when river flows are lower, which reduces flood risk, and the sluice can continue operating if it is needed during heavy rain.
Morgan Wray, Area Flood Risk Manager for Lincolnshire and Northamptonshire, said:
“The Grand Sluice has been at the heart of Boston for generations. This project will make sure it’s ready to continue its vital job well into the future.
The Grand Sluice has been in place for over 2 and a half centuries. Although it has been refurbished before, some of the components have now been in use since the early 1980s and are showing signs of deterioration and need replacing.
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