Why was the grand union canal built?

Answer 1

It wasn't. What is today known as the Grand Union Canal is comprised of three separate waterways: the Briumighma and Warwick Junction Canal, the Warwick and Napton Canal and the longest part, the Grand Junction Canal. The Grand Junction was opened throughout in 1805 following problems with the construction of the tunnel at Blisworth in Northamptonshire. The rest of the canal opened in 1800 and whilst the Blisworth Tunnel was being constructed, goods were transhipped by a double track horse drawn tramroad over the hill.

Answer 2

The strictly true answer is that it wasn't built. The Grand Union Canal Company was formed in 1929 and was an amalgamation of a number of waterways.

What we know today as the Grand Union Canal is made up of four waterways - the old Grand Junction Canal from London to Braunston in Northamptonshire, where it joined the Oxford Canal and uses that latter route to Napton on the Hill, then the Warwick and Napton Canal to Warwick, and finally the Birmingham and Warwick Canal to Birmingham.

The Grand Junction part was built to provide a more direct waterway route to London from the Midlands - particularly the coalfields of North Warwickshire via the Coventry and Oxford Canals, and the engineering manufactures of Coventry and Birmingham. Previously goods had to be shipped along the the Oxford Canal to the Thames at Oxford, and thence down the river for c. 100 miles to London. Apart from being a slower and far more circuitous route, The Thames was an old navigation and like all rivers, difficult to navigate at certain times of year, particularly after heavy rainfall. Many of the locks on the Thames today had not been built in the late 18th century, and staunches and flash locks were commonplace - all time consuming to use.

The Grand Junction was also a broad canal, with 14ft 6in wide locks against the 7ft width of the Oxford Canal's, which greatly facilitated the movement of boats.