Thomas Telford's Caledonian Canal: A great feat of engineering right in Scotland

In last Tuesday’s Back In The Day column, I showed how Telford went from a childhood of abject poverty in Dumfriesshire to becoming an architect and builder in England by the time he was 30 and in the latter years of the 18th century, he turned more and more to civil engineering projects such as building canals, roads and bridges.

I will be telling more about those projects and all his other achievements in this coming Tuesday’s Back In The Day column but it seems only right on its 200th anniversary to concentrate fully on the Caledonian Canal.

The idea of a ship canal using the lochs of the Great Glen had been around for decades, even before the Jacobite Rising of 1745-46 gave the UK Government the impetus and income to build one. 

READ MORE: Thomas Telford: The man who changed the face of Scotland

The funds raised from the many Forfeited Estates, as they were officially called, of Jacobite landowners plus the need to keep the people of the Highlands in gainful employment persuaded the Government to appoint Commissioners to oversee the construction of the Canal and they instructed James Watt, then a surveyor in Glasgow, to draw up a plan in 1773 for what would become the Caledonian Canal. Whisper it, but it was Watt, the inspirational figure of the Industrial Revolution, who first properly conceived of the Canal, and he was followed 20 years later by the great Scottish civil engineer John Rennie whose plan did not come to fruition.

Having established his reputation as an all-round civil engineer in Shropshire in particular, in 1801 Telford was asked to follow Watt and Rennie and draw up a plan for the Canal. The outbreak of the Napoleonic wars meant vessels on the east coast of Britain needed a safe route to the west coast, while the passage through the Pentland Firth was becoming ever more treacherous to navigate westwards.

The new canal would cut 500 miles off the length of the journey around the north of Scotland, and the French privateers could be easily kept at bay at both ends of the waterway. The alternative would be for British merchant vessels to risk the English Channel and the French Navy, or the Pentland Firth and gale force westerlies. If Telford could provide a workable solution, the project would gain Government approval, and it would also provide work for the many Highlanders who had been left in increasing poverty.

By that time, Telford (above) and Watt were friends, and the former immediately contacted the genius of steam. He wrote: “I have so long accustomed myself to look with a degree of reverence at your work, that I am particularly anxious to learn what occurred to you in this business while the whole was fresh in your mind.

The object appears to me so great and so desirable, that I am convinced you will feel a pleasure in bringing it again under investigation, and I am very desirous that the thing should be fully and fairly explained, so that the public may be made aware of its extensive utility. If I can accomplish this, I shall have done my duty; and if the project is not executed now, some future period will see it done, and I shall have the satisfaction of having followed you and promoted its success.”

Watt clearly gave Telford the benefit of his wisdom and experience because Telford’s survey and building plans relied heavily on Watt’s work – more homage than plagiarism it must be said. Telford completed his work in remarkably quick time, and he proposed a 60-mile canal from Corpach near Fort William to Inverness linking Loch Lochy, Loch Oich, Loch Ness and Loch Dochfour using 29 locks to raise and lower the canal levels with docks or basins at both ends, the impressive Clachnaharry sea lock being custom built for the Canal’s northern end.

In all, there would be 22 miles of canal proper, and the biggest series of locks was at the at the Corpach side, where eight giant locks would take vessels up 70 feet above sea level in the space of around 500 yards – the famous Neptune’s Staircase. For the whole canal, Telford estimated a cost of £400,000 and a construction time of seven years from 1804. Whisper it again, but the great man got it wrong.

It is often thought that Telford personally superintended the work but that is caused by the confusion between Thomas Telford and John Telford, the chief engineer on the site for several years. They were not related and we know that Thomas Telford spent many, many months away from the project, as you will learn on Tuesday.

READ MORE: Remembering Scotland’s greatest coal mining tragedy

Building the Canal, often in inclement weather, was backbreaking work, but the construction process did indeed employ many Highlanders who might otherwise have been destitute, and though it ran massively over budget and took nearly three times as long to complete as Telford estimated, it was finally completed in 1822.

On the official opening day, the Inverness Courier reported: “After a labour of nearly twenty years, and an expenditure of about £900,000 on this great national undertaking, the country will feel a great degree of satisfaction at the completion of it.”

The Courier reported that crowds on the banks of the Canal serenaded with “God Save The King” those dignitaries aboard the vessel chosen to make the first official trip along the Caledonian Canal – the Loch Ness Steam Yacht.

And in that name lies the reason why the Caledonian Canal was deemed Telford’s greatest failure as well as his towering success. For as he himself noted, the arrival of steamships pioneered on the Clyde would eventually render the Canal as obsolete as merchant sailing ships themselves.

It was not just the Caledonian Canal with which Telford transformed Scotland. Find out on Tuesday in the National just what he accomplished.