The Witham: Boston to Lincoln
By medieval times Boston was the best place to construct a bridge over the river Witham before it entered the Wash; hence that is the reason for its location. This also made it the best port on the river for sea-going vessels. By this time Lincoln had become a major English city with the Witham connecting it to the sea and Boston serving as its outport. Wool from the monasteries in Yorkshire and the Midlands could also reach Boston via the rivers Ouse and Trent, the Fossdyke canal and the Witham. However by the 18th century the lower reaches of the river through the Fens to the north of Boston had silted up and boats could only navigate it when there was sufficient water. It has been described as a failed river. In addition it frequently over-spilled its banks causing extensive inland flooding.
This problem was solved between 1764 and 1766 when a new 12 mile long channel was cut through the Fens, abandoning the old route, and the Grand Sluice was built just north of the town. The Sluice held back the fresh water so that the channel was deep enough for boats at any time whilst at the same time it kept out the tidal waters to prevent inland flooding from the sea. The new river channel was dug in three straight sections; this was a massive engineering project. Land owners were greatly concerned that they did not loose out to the scheme, so the line of the new cut was drawn to avoid this problem.
The new channel above Boston had high banks so the Fens on each side were protected against flooding. The Fens had been vast areas of unfenced common land subject to frequent flooding but now could be drained and divided into enclosed fields. The 22,000 acres West of Boston known as Holland Fen were enclosed in the 1770s.The East, West and Wildmore Fens totalling 40,000 acres to the north of the town were similarly dealt with between 1802 and 1812. The enclosure of the Fens was Boston’s contribution to the agricultural revolution.
There was some violent opposition to the drainage and enclosure of Holland Fen but the reclamation of the three northern Fens was peaceful. Cole seed, now known as oil seed rape, was often used as the first or “pioneer” crop before cereals were grown. Oats were usually the first of the cereals to be drilled; wheat later
The old Fens had been used for grazing large numbers of cattle as well as horses and geese. Cattle had been herded south on the hoof to feed London but cereals were now moved by ship. This led to the revival of the port and Boston’s second great period of prosperity. Boston came to supply about a quarter of London’s need for cereals and helped to feed the industrial revolution in the growing northern cities.