The jewel in the crown of our 11-mile UNESCO World Heritage Site here in Wrexham County Borough is receiving a major health check this March. Carried out once every 20 years, engineers from national waterways charity Canal & River Trust have completely emptied Pontcysyllte Aqueduct of water to check that the 307m-long structure, built to carry the Llangollen Canal across the Dee Valley 38m below, is in good working order.
Image; Photography by Joe Bickerton
Pontcysyllte Aqueduct, nicknamed the ‘stream in the sky’, was built in 1805 by pioneering canal engineer Thomas Telford, and was granted World Heritage Status in 2009. Formed of a cast iron trough, supported by iron arched ribs and carried on 18 stone pillars, the aqueduct boasts over 11,000 bolts. As part of being a good custodian of this astonishing piece of industrial heritage, the Canal & River Trust’s engineers are inspecting bolts, joints and seals along the aqueduct’s drained channel.
While the aqueduct is inspected regularly from the towpath, completely emptying the water is allowing the engineers to inspect areas that are normally hidden. Uniquely, this includes looking at the underside of the towpath, as well as the caulking of still water-tight joints along the cast iron trough which were sealed over two centuries ago with Welsh flannel dipped in boiling sugar.
The inspection is part of a wider maintenance programme for the aqueduct. Since Christmas, a team from the Canal & River Trust has been working alongside specialist blacksmiths to carry out routine maintenance of the parapets.
Emptying the aqueduct has taken a lot of planning, as the canal carries a daily water supply that feeds over 70,000 homes and businesses in Cheshire. The Canal & River Trust has worked with United Utilities, which has put in place a bypass to continue supplying water from the River Dee. The inspection and maintenance has been taking place over the winter months when fewer boats are using the canal network, with the aqueduct planned to be reopened upon the outcome of a successful inspection by 15 March 2024.
Canal & River Trust engineer Sally Boddy said: “It’s the engineer's job to be the voice of the aqueduct, to spot any things that might be causing it damage or may need fixing in years ahead. Draining Pontcysyllte Aqueduct for inspection helps us to make sure it is in good condition and to plan any future works that will need doing.
“It’s a privilege to work on such an iconic structure and see the handiwork of the canal engineers who built it over two centuries ago. The work we are carrying out today is part of that great legacy and will help Pontcysyllte continue to stand strong. But we’re facing challenges that could not have been imagined by Thomas Telford, with climate change-driven floods and storms taking their toll on our 250-year-old canal network. As the custodians of an incredible portfolio of aqueducts, locks and bridges – the third largest collection of listed structures in the country – we are determined to keep canals alive and preserve this rich heritage.”
The Canal & River Trust has had to raise more than £185,000 to carry out the works at the UNESCO World Heritage Site. A crowd funding campaign is being run to raise money to support the vital works to this important part of industrial heritage. To donate, visit: https://bit.ly/Ponty_Aqueduct
Over 100 large-scale projects are being carried out across the country by the Canal & River Trust this winter to replace worn-out lock gates, inspect tunnels and aqueducts, repair centuries-old masonry and brickwork, together with a host of other important heritage and conservation tasks. It’s a massive task to keep canals in working order for boats, for local communities, and for the benefit of wildlife, involving the Canal & River Trust’s passionate team of specialists and thousands of dedicated volunteers, donors and partners.
You may have also spotted the works featured on BBC's Countryfile last weekend. with Matt Baker & co. To catch-up, watch the episode on the BBC i-player via this link. https://www.bbc.co.uk/iplayer/episode/m001x0yq/countryfile-pontcysyllte-canal
Image; Photography by Joe Bickerton