The Grand Sluice, Boston was completed in 1766 and was the culmination of many years' work to protect the Lincolnshire town of Boston and surrounding area from flooding, improving navigation from Lincoln to Boston and releasing large tracks of land for arable farming through managed drainage. Members of the Institution of Civil Engineers, the Lord Lieutenant of Lincolnshire, local dignitaries and invited guests helped commemorate the opening of the Grand Sluice at two events in Boston at the beginning of October.
The first of the celebratory events was held on Monday 3rd October when Neil Wright, Chairman of the Society for Lincolnshire History and Archaeology, gave an informative talk at the White Hart in Boston, on the history of, and the need for the construction of the Grand Sluice and the benefits that it has provided to the local community and surrounding area for the last 250 years.
The second event was on Monday 10th October where Mr Toby Dennis, Lord Lieutenant of Lincolnshire addressed the Mayor and Mayoress of Boston, and a party made up from county and local councillors, representatives from the Canal & River Trust and other invited guests. Mr Dennis unveiled a blue heritage plaque sited on a stone pillar adjacent to the Grand Sluice and an illustrated interpretation board outlining the history and benefits of the project. The party then made its way down the River Witham on the Boston Belle, with Neil Wright acting as guide, to the Haven and the entrance to Boston dock, the site of the proposed Boston Barrier, where Adrian Clack of the Environment Agency described the proposal.
Matt Huddleston, ICE Branch Chair for Lincolnshire said, "The blue heritage plaque has been dedicated by the Institution of Civil Engineers (ICE), Lincolnshire County Council, Boston Borough Council, Canal and River Trust, the Environment Agency, The History of Boston Project, the Society for Lincolnshire History and Archaeology, Witham East Placecheck Group and Internal Drainage Boards in recognition of the Grand Sluice as a work of civil engineering which continues to serve its original purpose, and its historic importance to society and the landscape of Lincolnshire for the last 250 years.
The sluice has significance as possibly the earliest tidal outfall sluice and was a great achievement of the engineers involved: John Smeaton; Langley Edwards; and John Grundy. This structure was built to control waters in the River Witham, separating the tidal Haven from the non-tidal river sweeping down across country from Lincoln and beyond and allowed reclamation of 111,000 acres of productive agricultural land."
Molly McKenzie, ICE East Midlands Regional Director added, "It is fantastic that we are celebrating the engineering achievements of the Grundy's and Smeaton and that their work has not only benefitted the community of Boston, but has had an impact for the better on others much further afield."
"It is a testament to their skill and works, that the Grand Sluice remains largely as it was when finished and is still protecting the fenlands of Lincolnshire as it was designed to do so 250 years ago."
The River Witham, which flows from Lincoln to Boston, was wide and too shallow on the approach to Boston and quite often silted up rending it unsuitable for use as a navigation channel, hampering trade between Lincoln and Boston and beyond. In addition to the threat of flooding to Boston, the fenlands to the north of town often flooded and could only be used for grazing of livestock.
Leicestershire born land surveyor, and later a civil engineer, John Grundy Senior initially proposed solutions to the issues which were then taken up by John Grundy Junior and John Smeaton. The proposal that was settled upon is that we see today, with a straightened water course through Boston, drainage of the surrounding fens in to, and control of the flow out and in through the sluice. The works enabled Boston to grow in prosperity and importance to such an extent that at one time it became larger than Lincoln and it supplied one quarter of London's grain requirements.