Whilton Locks - History

History

The Grand Junction Canal was authorised by an Act of Parliament on 30 April 1793, and was to run over 90 miles (140 km) from Braunston on the Oxford Canal to Brentford near London, where it would join the River Thames. Construction of the northern section, which included the Whilton locks at Buckby, was complicated by the need for two tunnels, one to the north of the locks near Braunston, which was 2,042 yards (1,867 m) long, and the other to the south at Blisworth, which was 3,057 yards (2,795 m) long. Despite encountering quicksands in Braunston Tunnel, it was finished on 21 June 1796, and the canal opened to Weedon Bec, around 2.7 miles (4.3 km) to the south of the locks. Shortly afterwards, it was extended further south to Blisworth, but there were serious problems with Blisworth Tunnel, which had failed in January 1796. William Jessop was the engineer and wanted to abandon the idea of a tunnel. He proposed to build 29 locks to get beyond Blisworth, but was persuaded to try a different alignment by three engineers who were brought in to advise. Low level headings were cut to drain the main workings of water, and the tunnel opened on 25 March 1805, the last part of the canal to be completed. The Grand Junction Canal became part of the Grand Union Canal in 1929, following amalgamation with the Regents Canal, the Warwick and Birmingham Canal and the Warwich and Napton Canal.

Below the bottom lock was a long level pound stretching to beyond Blisworth Tunnel. The seven locks raised the level of the canal by 63 feet (19 m) to a fairly short summit pound, which passed through Braunston Tunnel and then descended through five locks to Braunston. The locks were built wide enough to take two narrow boats side by side, in the hope that the canals beyond the northern terminus could be persuaded to widen their locks and that wide barges carrying 70 tons could be operated.

The locks at Buckby were all built with side ponds, to conserve water. There are maintained at an intermediate level between the upper and lower pound. When a lock is emptying, water from the top of the lock fills the side pond, and the rest is then discharged to the lower pound. When a lock is filling, the bottom of the lock is filled from the pond, and the rest is drawn from the upper pound. Typically, this system uses 40 per cent less water, but the ponds have been disused for a long time, and an electric pump is now used to pump water from the bottom of the flight to the top. The Grand Junction Canal experimented with side ponds from the early 1800s. The locks at Bourne End had several radial ponds, but use of the ponds was abandoned because it took too long to use the lock. Those at Buckby had two rectangular side ponds per lock, at different levels, and this design was eventually installed at most locks between Buckby and lock 45 at Bulbourne, the junction with the Wendover Arm.