Most of the time that I write on this site I am whinging about something or other and in these days of the Credit Crunch there is precious little to be cheerful about. But today is different; we have something to celebrate. Finally, the achievements of two British engineers have been recognised for a wonderful construction in Wales that has proved its worth over many years. I write, of course, about the Pontcysyllte Aqueduct on the Llangollen Canal.
This magnificent structure designed and constructed by Thomas Telford and William Jessop took 10 years to build and was completed in 1805. The aqueduct - the longest and highest in Britain - is 1007 ft [305 m] long and carries the Llangollen Canal across the valley of the River Dee at a height of 126 ft [38.2 m]. The canal has been a success throughout its life, as an industrial waterway and later as a pleasure boat route and a water supply duct. On 27th June 2009 UNESCO officials meeting in Seville awarded the Pontcysyllte Aqueduct and 11 miles of the LLangollen Canal the status of World Heritage Site.
Construction of the canal opened up mid-Wales and roads and tramways were built to bring products to the canal for shipping into the Midlands and London. The canal could have been constructed using locks to step down into the valley and then more locks to go back up the other side. Building an aqueduct was a much bolder solution and many predicted disaster with the whole structure collapsing under its own weight. The Pontcysyllte Aqueduct is made from sections of cast iron trough, bolted together and supported on 19 stone pillars. There is a towpath on one side with a safety railing but the other side is completely open. It is possible to fall over the side of a barge and drop straight down into the valley. The open trough side was provided with holes to allow safety railing to be added later if thought necessary. It has not been thought necessary for 200 years but the Health & Safety Executive is looking to get that changed. The Llangollen Canal is included in the citation because the system takes water from the River Dee via the man made weir that is the Horseshoe Falls. This water supply keeps the canal topped up with fresh water but now transports domestic water from the Dee to the Hurleston Reservoir 25 miles away.
The structure has required very little maintenance and the original seals between trough sections were still OK after 200 years in operation.
The whole Llangollen Canal construction of canal, tunnels and aqueduct was a triumph of its day and it is good that the beauty of the construction and the quality of the engineering are still recognised today. In those days Britain built things that we could be proud of. Now we construct nothing but financial instruments.
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