The Barton Swing Aqueduct is a moveable navigable aqueduct in Barton upon Irwell, Greater Manchester, England. It carries the Bridgewater Canal across the Manchester Ship Canal. The swinging action allows large vessels using the ship canal to pass underneath and smaller craft, both narrowboats and broad-beam barges to cross over the top. The aqueduct, the first and only swing aqueduct in the world, is a Grade II* listed building, and considered a major feat of Victorian civil engineering. Designed by Sir Edward Leader Williams and built by Andrew Handyside and Company of Derby, the swing bridge opened in 1894 and remains in regular use.
The Barton Swing Aqueduct is a direct replacement for the earlier Barton Aqueduct, a masonry structure crossing the River Irwell and completed in 1761. The construction of the Manchester Ship Canal in the 1890s necessitated the replacement of this structure, as the height of ships using the new ship canal was too great to pass under the old aqueduct. An alternative scheme involving the use of a double lock flight was rejected, because of the need to conserve water in the Bridgewater Canal above.
The new aqueduct was designed by Sir Edward Leader Williams, engineer to the Manchester Ship Canal Company, and was built by Andrew Handyside and Company of Derby. The first barge crossed the new aqueduct on 21 August 1893, and it opened to commercial traffic on 1 January 1894. Williams was also involved with the Anderton Boat Lift, another moving canal structure in the region.
Construction work began in 1890, with the demolition of a Roman Catholic school on the south bank of the ship canal. The scale of the operation meant that the course of the River Irwell had to be temporarily diverted around the site, so that the central island could be built on dry land.
The aqueduct is a form of swing bridge. When closed, it allows canal traffic to pass along the Bridgewater Canal. When large vessels need to pass along the ship canal underneath, the 1,450-tonne (1,430-long-ton; 1,600-short-ton) and 330-foot (100 m) long iron trough is rotated 90 degrees on a pivot mounted on a small purpose-built island. Gates at each end of the trough retain around 800 tonnes of water; additional gates on each bank retain water in their adjacent stretches of canal. The aqueduct originally had a suspended towpath along its length, about 9 feet (2.7 m) above the water level of the Bridgewater Canal, which has now been removed.