Thomas Telford - Ellesmere Canal

Ellesmere Canal

Telford's reputation in Shropshire led to his appointment in 1793 to manage the detailed design and construction of the Ellesmere Canal, linking the ironworks and collieries of Wrexham via the north-west Shropshire town of Ellesmere, with Chester, utilising the existing Chester Canal, and then the River Mersey.

Among other structures, this involved the spectacular Pontcysyllte Aqueduct over the River Dee in the Vale of Llangollen, where Telford used a new method of construction consisting of troughs made from cast iron plates and fixed in masonry. Extending for over 1,000 feet (300 m) with an altitude of 126 feet (38 m) above the valley floor, the Pontcysyllte Aqueduct consists of nineteen arches, each with a forty-five foot span. Being a pioneer in the use of cast-iron for large scaled structures, Telford had to invent new techniques, such as using boiling sugar and lead as a sealant on the iron connections. Eminent canal engineer William Jessop oversaw the project, but he left the detailed execution of the project in Telford's hands.

The same period also saw Telford involved in the design and construction of the Shrewsbury Canal. When the original engineer, Josiah Clowes, died in 1795, Telford succeeded him. One of Telford's achievements on this project was the design of the cast-iron aqueduct at Longdon-on-Tern, pre-dating that at Pontcysyllte, and substantially bigger than the UK's first cast-iron aqueduct, built by Benjamin Outram on the Derby Canal just months earlier.

The Ellesmere Canal was completed in 1805 and alongside his canal responsibilities, Telford's reputation as a civil engineer meant he was constantly consulted on numerous other projects. These included water supply works for Liverpool, improvements to London's docklands and the rebuilding of London Bridge(c.1800).

Most notably (and again William Pulteney was influential), in 1801 Telford devised a master plan to improve communications in the Highlands of Scotland, a massive project that was to last some 20 years. It included the building of the Caledonian Canal along the Great Glen and redesign of sections of the Crinan Canal, some 920 miles (1,480 km) of new roads, over a thousand new bridges (including the Craigellachie Bridge), numerous harbour improvements (including works at Aberdeen, Dundee, Peterhead, Wick, Portmahomack and Banff), and 32 new churches.

Telford also undertook highway works in the Scottish Lowlands, including 184 miles (296 km) of new roads and numerous bridges, ranging from a 112 ft (34 m) span stone bridge across the Dee at Tongueland in Kirkcudbright (1805–1806) to the 129 ft (39 m) tall Cartland Crags bridge near Lanark (1822).

Telford was consulted in 1806 by the King of Sweden about the construction of a canal between Gothenburg and Stockholm. His plans were adopted and construction of the Göta Canal began in 1810. Telford travelled to Sweden at that time to oversee some of the more important initial excavations.

Many of Telford's projects were undertaken due to his role as a member of the Exchequer Bill Loan Commission, an organ set up under the Poor Employment Act of 1817, to help finance public work projects that would generate employment.