Introduction to Fourteen Locks and the Monmouthshire Canal

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Fourteen Locks is one of the most important engineering triumphs of the Monmouthshire Canal and it is impossible to tell the story of locks without understanding why a canal was needed in the first place. 



The major problem facing industry towards the end of the eighteenth century was transport. The Industrial Revolution in the South Wales Valleys was initially based on iron. Roads were often poor so that the carriage of heavy or bulky goods was slow and expensive in man power. Water was the alternative. In South Wales the rivers were not conducive to boat transport. The building of the artificial waterways (canals) in England opened a new chapter in transport history that was to bring prosperity to the South Wales ports.

The high ground to the north of the South Wales Valleys was rich in minerals. The twenty mile long ridge from Blaenavon to Hirwaun contained the iron, the limestone and the coal needed for the ‘new’ works. The English ironmasters who moved into the area were used to using canals to export their goods so naturally looked to similar facilities in the South Wales area. 

Given the geography of the area the construction of the canal required ingenuity and sheer hard labour. In the first committee meeting of The Monmouthshire Canal Company held on 10th July 1792 Thomas Dadford Junior, the engineer responsible for construction of both the Main Line and the Crumlin Arm, stated that he wanted 200 wheelbarrows, six dozen casting tools and six dozen shovels! It would be back breaking work, especially constructing the locks.

construction web

The Monmouthshire Canal was authorized by Act of Parliament in 1792. The Main Line stretched from Pontnewynydd, NW of Pontypool via Pontymoile to Newport and an additional branch stretched from Malpas to Crumlin.  

The Main Line was 11 miles long with 42 locks. 11 of those locks were on the 2 miles from Pontymoile to Pontnewynydd and that section was often short of water. It was replaced by a tramroad soon after 1812 and closed completely in 1854. 

The Crumlin Arm or Branch was also 11 miles long and had 32 locks lowering the canal by 358ft. Even though it is no longer fully navigational, the Cefn  Flight of 14 locks at Rogerstone  was one of the wonders of the British canal system when it was constructed. 

The fiftieth meeting of the committee of the ‘Monmouthshire Canal Navigation’ held at the Westgate House Inn in the town of Newport on Wednesday the 25th day of November 1795 records the terms of the contract awarded to Walter Waters as follows:

‘For raising stone, hauling and setting the masonwork at the rate of Seven shillings per perch of 36 cubic feet;

Raising, hauling and setting the trunk stones at four shillings per yard superficial measure;

Finding and hauling the stones and sheeting the bottom of the locks at three shillings per superficial yard;

Cutting the several lock pits at five pence per cube yard and backing the said 15 locks at £10 each;

The Company only to find Lime, Sand, Barrows, Planks and Water in the Canal close to the Upper Lock.’

N.B. Notice that Walter Waters was engaged to build 15 locks!

Nothing was left to chance. Thomas Dadford Junior was ordered that if he found that a certain Edward Lewis was not likely to have the water in proper time at the head of the locks then he was to set other hands to do the work. However, there were problems, with at least one complaint of trespass for the purpose of digging stone for lock building. The theft of materials was taken very seriously with a reward of five guineas being offered for information leading to the arrest of the person or persons who stole timber in the August of 1797.

The locks follow the contours of the land and are quite unique in their construction comprising of five pairs of locks, one triple set of locks and one single lock. A clever system of pounds and ponds ensured that water was retained as much as possible for operational purposes. (See map above)