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Bridging the gap

ROBERT BULLARD tells the story behind the greatest, but ill-fated, aerial waterway in the world

Two hundred years ago this year, a procession of canal boats drifted jubilantly along the Pontcysyllte Aqueduct – to the accompaniment of union jacks, ‘Rule Britannia’ and a 15-gun salute. It was a spectacular occasion. And there was good reason to celebrate. Ten years after it had first been proposed, the Pontcysyllte Aqueduct was finished and open to traffic. But all was not quite what it seemed. (Country & Border Live, April 2005)

On the surface people’s moods were high. Never before had such a long and high aqueduct been built, and never again! Indeed, Telford and his colleagues must have proudly reeled off the statistics to all those present.

The dignitaries were travelling in a 1000 feet long iron trough, supported by 18 massive pillars, and they were raised 125 feet above the Dee Valley, from where a cheering crowd of 8000 people looked up and waved.

But despite being of breathtaking height and length, the aqueduct was also, as some must already have feared, destined to become a monument to the short-lived boom and bust of Britain’s canal age.

And the intrigue behind who designed it and the deliberations over the canal’s chosen route has fascinated people for centuries.

Choosing the route

The Pontcysyllte Aqueduct was to be the jewel in the crown of the Ellesmere Canal. Proposed in August 1791, when ‘canal mania’ was sweeping the country, it would link the Wirral with Shrewsbury and be a canal system of national importance.

After a public launch, held at The Royal Oak, Ellesmere, a committee was formed to oversee the work, comprising no less than the Earl of Powys, along with the Mayors of all three cities that were to be joined together - Liverpool, Chester and Shrewsbury.

Under the original proposal, put forward by the local engineers John Duncombe and William Turner, the canal was to have run from the Mersey to Shrewsbury, via the Dee, near Chester. The route was estimated to cost £171,098, of which £67,456 was for the main line. (There was clearly no rounding of figures in those days!)

But in August 1792, the committee called upon the additional experience of the more nationally reputed William Jessop, from Newark, ’an Engineer of Approved Character and Experience’. And Jessop proposed what became a fateful more westerly route in which the canal would run through and open up the coalfields of North Wales - through Wrexham and Ruabon - before heading to Shrewsbury via Frankton.

However, Jessop’s route was more technically challenging. It would need a 2.5mile tunnel at Ruabon and literally dozens of locks to lift boats up from the Chester Plain to the edge of the Welsh Mountains. His main line was also three times as expensive. But it was what he confidently described it as the ‘best adapted to the Accommodation of the Country with Coal and Lime and to the General Commercial Interests of the Public’, and it won the Committee’s approval.

Construction begins

Construction of the overall canal had started according to plan. In the north end, a stretch from the small town of Netherpool (which became Ellesmere Port) to Chester was opened in 1795.

Building this stretch first, it was hoped, would bring in revenue that would help pay for the remainder; and in addition to freight transport, a fashion soon developed for people to take canal rides - 1s6d to sit at the better end of the boat, and 1s otherwise - during which passengers were offered tea, coffee and refreshments.

Good progress was also taking place at the southernmost end, where a branch was opening from Frankton in Shropshire to the lime quarries of Llanymynech, where it would join the Montgomery Canal that went on to Welshpool and Newtown.

But crossing the Dee Valley was always going to be a more serious challenge, and which would take longer to solve.

Under the original 1793 proposal – for which Duncombe and Turner were joined by the surveyor, Arthur Davies – there would be a narrow three-arched aqueduct, with a series of locks on each side of the valley. However, this was rejected as too time consuming for the boatmen and too costly in terms of water, power and maintenance. So, after some indecision in 1794, the committee finally approved a high-level iron aqueduct with no locks.

But who designed it? Was it Jessop, or was it the ‘newcomer’ Thomas Telford – the latter having joined the list of engineers in October 1793?

For yeas historians have given fairly exclusive credit to Telford, fuelled maybe by the man’s later road-building talents - and his boastfulness. Telford was also uniquely placed, people think, to have copied and tested out the iron trough design which had also been used in 1796 at Longdon, on the Shrewsbury Canal, and where Telford was the engineer.

But opinion now seems to have swung back towards Jessop, if only a little. After all, Telford had never worked with iron before, whereas Jessop had been an ironmaster since 1790. And Jessop too was able to copy from elsewhere – since his business partner, Benjamin Outram, was working on an iron aqueduct on the Derby Canal, at Butterley.

Rather than either of them acting independently, it is more likely that the two engineers pooled their ideas and worked on the innovatory design together. And the only reason Jessop omitted Telford’s name from the records was because, as the senior of the two, he felt it his duty to take full responsibility for what was such an ambitious project.

Competition ahead

Whoever we decide to credit – and there is no conclusive proof either way - the aqueduct’s fanfare opening took place on 26th November 1805. The all-iron design (built by William Hazeldine of Shrewsbury), and its length and height, represented the forefront of engineering.

Indeed, the neighbouring 600feet long Chirk Aqueduct, which had been completed as recently as 1801, was a compromise between new and old technologies, with an iron floor and masonry sides. And even Pontcysyllte’s pillars – for which huge stone blocks had to be winched up on a primitive scaffold and then manhandled into position, way above the valley floor – were a feat in themselves.

However, the aqueduct had ended up costing £47,000 (approximately £2m today), which was 35% more than predicted. And, however impressive its many accomplishments – and only one man died during its six years of construction - its future usage was tied up with that of the viability of the overall Ellesmere Canal.

Although still not complete, the canal’s construction costs were spiralling out of control and had now reached £410,000 (£16.5million). And things were further threatened by the high cost of the planned tunnels and locks between Pontcysyllte and Chester, as a result of which the line north of the aqueduct was never finished.

And the incompletion of the canal’s summit meant that, with 60,000 gallons used every time a boat moved through the locks, there were acute water supply problems for several years.

More threateningly, the opening of the Shrewsbury Canal made coal from East Shropshire cheaper than that of Ruabon, which meant that work on the canal south of Weston, towards Shrewsbury, was first postponed and then abandoned.

Little wonder therefore that the full length of the 60mile Ellesmere Canal was not built – let alone did it become part of a national canal network, as had been planned. And although the Chester Canal eventually joined up the isolated north and south ends in 1808, this was via Whitchurch rather than the area around Chirk.

And in the decades ahead things only got worse, as the railways – even at 30mph – nudged themselves forward as the new method of transportation. Indeed, anticipating what lay ahead, Jessop had earlier proposed changing the viaduct to a railway bridge, but this had been rejected.

But whatever the impermanence of Britain’s canal age, nobody denies that the Pontcysyllte Aqueduct is one the most spectacular waterways in the world – and always has been, ever since its opening 200 years ago.

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