The Pontcysyllte Aqueduct

Yet but for some timely twists of fate, it might never have been built at all – and controversey still rages over whether the great Thomas Telford or the more modest William Jessop should be credited with the pioneering design. Find out more with our Pontcysyllte timeline.

Circa 1790
A group of enthusiasts were busy tackling the problem of how best to link the River Mersey at Netherpool, the Dee at Chester and the River Severn at Shrewsbury. After due consideration they proposed two viable routes: a western scheme which involved a 1,235 yard tunnel at Chirk and an eastern scheme which veered off from the Chester Canal at Tattershall. This option avoided the Dee Valley and would not have required an aqueduct at all.

November 1791
William Jessop, a well respected canal engineer, was engaged to choose between the two.

August 1792
Jessop submitted a report recommending the western route with an aqueduct crossing the Dee. However, Jessop’s planned aqueduct was not at summit level. Jessop stated an aqueduct at this height would prove too expensive and instead suggested a crossing 24ft below summit with three locks at each end.

September 1792
The Ellesmere Canal Company was formed.

September 1793
Jessop’s talents were in high demand throughout the country and he was unable to supervise construction. The Committee advertised for a supervising engineer and Thomas Telford was duly appointed.

January 1794
Jessop’s original plan for a three-arched masonry aqueduct below the summit was approved, but Telford expressed disaffection was the scheme due to amount of water that would be lost through locks – and the subsequent need to pump water back up the hill.

February 1795
Telford started working for the Shrewsbury Canal Company and developed the idea of building an aqueduct out of iron.

July 1795
Just five months later, Jessop wrote a further report which extolled the advantages of building an iron aqueduct at summit level, 125ft above the River Dee.

August 1795
The pioneering plans for a cast iron aqueduct were approved. Work began.

1800
Delays in construction meant that five years later, the towering stone columns of the Pontcysyllte Aqueduct were still not completed. Also at this time, the northern section of the western scheme was abandoned; the waterway would never go much further than Pontcysyllte. It is extremely doubtful whether the aqueduct would ever have been built if this decision had been made earlier. As it was, suggestions were put forward to use it as a railway instead of a water channel.

November 1801
Fortunately for today’s pleasure boaters, the Committee returned to their original choice of a water channel.

26th November 1805
With much fanfare and aplomb, the Pontcysyllte Aqueduct was officially opened. The band played Rule Brittania and some 8,000 people attended the grand ceremony. The Earl and Countess of Bridgwater were among the first to cross the aqueduct, leading a procession of boats which returned, appropriately, with coal from the local pits.

1950
The impressive aqueduct became popular with pleasure boaters and it duly survived threats of closure in the late 1950’s.

Today
More than ten thousand boats float through the air above the Dee every year and the Pontcysyllte Aqueduct is under consideration for World Heritage status.

Controversey
The passing of time has not silenced the debate over which of our two great engineers are responsible for the Pontcysyllte Aqueduct. Tradition, the media at large, the inscription on the plate at the entry to the aqueduct and the alleged egotism of the man himself have passed the honour to Telford – he actually took credit for it in his autobiography - but there is much to support Jessop’s claim.

Jessop’s refusal to attend the opening ceremony was characteristically modest, as was his reluctance to assert his responsibility for the aqueduct. However, at the time of the Pontycysyllte Aqueduct’s construction, Jessop was at the peak of his canal building career – he has been labelled one of the greatest canal engineers in the world. Telford, on the other hand, was more an expert in the field of roads and bridges.

Unfortunately we will probably never know who properly deserves kudos for this masterpiece of 18th Century engineering.

Find out more about the Pontcysyllte Aqueduct

Find out more about our canal heritage

In this section ...

Facts and Figures »

Become an expert on all things 'Pontcysyllte' with our fascinating facts and figures. More »