The Union Canal runs from the Lochrin Basin, in the Tollcross area of Edinburgh and links with the Forth and Clyde Canal at Falkirk, close to the Roman Antonine Wall.
Opened as the Edinburgh & Glasgow Union Canal in 1822, it was principally the work of Hugh Baird (1770 - 1827), with some assistance from Thomas Telford (1757 - 1834). Alternative plans for the route, proposed by engineers Robert Stevenson (1772 - 1850) and John Rennie (1761 - 1821), had been argued over for several years. This is a contour canal, which means that it follows the natural topography, remarkably retaining the same height throughout its 31 miles (51 km) length and therefore not requiring locks. Features of the canal include the only canal tunnel in Scotland, near Falkirk, which is 640m (2070 feet) long and the Avon Aqueduct, which is the longest and tallest aqueduct in Scotland (247m / 810 feet long and 26m / 86 feet high). Of the three other aqueducts, the best known and most accessible is at Slateford in Edinburgh, a mere 152m (500 feet) long and 23m (75 feet) tall.
The Union Canal is operated by British Waterways, and along with the Forth & Clyde Canal, has been subject to a major renovation under the auspices of a Millennium Commission project. This has included the removal of major obstructions, such as the 1 mile (1.5 km) in-filled section through Wester Hailes in SW Edinburgh. The centre-piece of the project has been the Falkirk Wheel, a 35m (115 feet) diameter boat-lift, built to transport boats from the height of the Union Canal down to the Forth & Clyde Canal and vice versa, using state-of-the-art mechanical, electronic and hydraulic engineering.
The Union Canal links Edinburgh, Ratho, Broxburn, Winchburgh, Linlithgow and Falkirk. An extension, which would have taken the canal on to Leith Docks via what is now Princes Street Gardens, was never built. The time of the railways had come, and it was they which exploited this route into the heart of Edinburgh. Peculiarly, Canal Street was built (under North Bridge), although this has subsequently been lost under Waverley Station.