Posted 16th Feb 2018
In the next of our History of the Waterways features, courtesy of Insure4Boats and the Canal and River Trust, we find out about the Iron Trunk Aqueduct
If you're travelling Britain's waterways on your canal boat or narrowboat, you're probably used to being at ground level, passing riverbanks and navigating tunnels
However, if you cross the River Great Ouse, you'll suddenly find yourself high up in the air - welcome to the Iron Trunk Aqueduct!
Also called the Cosgrove Aqueduct, it's the world's first wide canal cast iron trough aqueduct and is set some 12 feet above the river's surface. A dazzling (and occasionally dizzying) route, there are views provided for as far as the eye can see, including over the Buckinghamshire and Northamptonshire countryside.
As you may expect, building the aqueduct proved to be a difficult task. Designed by Grand Union Canal's company engineer, William Jessop, to match up the levels of the river - it was originally a three-arch brick viaduct, to avoid having to build several locks. Opened in 1805, it wasn't long before a section of the embankment fell in - even worst, the entire aqueduct collapsed in 1808, cutting off the canal itself.
Another company's engineers, Benjamin Bevan, was given the task of replacing the aqueduct. As a fan of Thomas Telford's iron trough aqueduct at Pontcysyllte, he was determined to design and build the world's first wide canal cast iron trough. With the iron bars cast at the Ketley foundry at Coalbrookdale (where Telford's also were) - the enormous structure was transported by canal and painstakingly built - eventually being unveiled in January 1811. Floor arches and ribs were added shortly after to provide extra strength - and when you're up there, you'll be glad it's added.
Did you know?
- The collapse of the first aqueduct resulted in a legal battle between the canal engineer and contractor. The contractor lost, having to pay damages for loss of trade.
- Cattle creeps (small pathways) were added under the aqueduct, to ensure cattle could still cross from field to field.
- The aqueduct is 15 feet wide and 6 foot 6 inches deep.
- In 2011, the Iron Trunk aqueduct won the final round of 'The Big Lottery Fund: The People's Millions' - winning £60,000 in funding. The money was used to celebrate the aqueduct's 200th birthday by cleaning and repainting the cast iron structure in its original colours.
Image credit: Keith J Smith. / Alamy