Behold, the Slateford Aqueduct. It stands as a testament to engineering ingenuity. This navigable aqueduct carries the Union Canal over the Water of Leith. We are standing in Slateford, Edinburgh, Scotland.
Completed in 1822 the Slateford Aqueduct boasts eight impressive arches. It spans a length of 500 feet. That is about 150 meters. Its designer was Hugh Baird. He received advice from the renowned Thomas Telford.
The Slateford Aqueduct is modeled on Telford’s Chirk Aqueduct. The masonry work was advertised to builders in March 1818. Hugh McIntosh got the construction job. He was already working on the canal’s east end.
Baird sought Telford’s input on the ironwork. James Thomson from William Hazledine’s company contacted him. This company had worked on the Pontcysyllte Aqueduct. Baird worried about hiring a contractor so far away. He also questioned if the contract should include assembly.
Craven, Whitaker, and Nowell won the contract. They had successfully built a stone bridge over the River Ouse. Construction began in March 1819. The Slateford Aqueduct officially opened in 1822. In 1970, it gained recognition as a category B listed building.
Early canal aqueducts relied heavily on masonry and puddling for watertightness. After the Iron Bridge’s success in 1789, Telford used cast iron on aqueducts. The Slateford Aqueduct uses an iron trough. This avoided needing a deep layer of puddle clay. This reduced the amount of masonry required.
Each of the Slateford Aqueduct’s eight arches spans 50 feet. That is about 15 meters. The aqueduct reaches 75 feet above the Water of Leith. Its piers are battered, wider at the base. The spandrels are hollow. This was an innovation by Telford. Inside, stone arches run parallel along the length. They are linked laterally. You can walk inside the stonework on the north side.
The Slateford Aqueduct carries the Union Canal over Inglis Green Road. It also crosses the Water of Leith. To the north stands the Slateford Viaduct. It carries an active railway line. The iron trough is seven feet deep. It measures 13.5 feet wide.
The Slateford Aqueduct is more than just a structure. It represents innovation. It showcases collaboration. It embodies the spirit of Scotland’s industrial heritage. As you stand here, consider the visionaries who shaped this remarkable feat of engineering.