England underwent an extensive Canal Age in the mid Eighteenth Century, lasting for longer than a century. Waterways provided a cheaper means to move goods across a nation, helping to spark the country’s rapid transformation during the Industrial Revolution. Canals offered remarkable improvements over rutted, muddy overland routes and provided the best transportation alternative in the decades before the invention of railroads.
Cottage beside Bridgewater Canal, Lymm, Cheshire by Andrew Green via Flickr (cc)
The Bridgewater Canal was frequently cited as the blueprint for a network that quickly evolved across the nation after it opened in 1761. Its builder and owner, Francis Egerton the third Duke of Bridgewater, envisioned a canal as a better way to move coal from his mines at Worsley to nearby towns. Coal from his mines heated homes and fueled industrial expansion. Egerton’s design hadn’t been tried in England before; his was the first canal that didn’t following an existing waterway. He kept his design simple. The canal followed natural topography so it didn’t require locks anywhere along its 65 kilometre (39 mile) path from Leigh to Runcorn; near Liverpool and Manchester. It was a narrow canal designed for small slender boats and it served its purpose well enough to inspire numerable imitators.
Manchester Ship Canal
A ship in the Ship Canal, Manchester by Neil Howard on Flickr (cc)
The Manchester Ship Canal, by contrast, was one of the last canals built and it didn’t arrive on the scene until the 1880’s. It traced the original paths of the rivers Mersey and Irwell, in a general manner. Industrialists in Manchester felt that they were at a disadvantage because of the city’s inland location inaccessible to oceangoing vessels. Manchester businesses paid dearly for railroad access to the docks at Liverpool. The city lobbied for relief and Parliament approved construction despite Liverpool’s strong objections. Construction required an immense effort with extensive dredging, numerous locks, and high overhead bridges to accommodate the passage of large cargo ships. These improvements allowed merchant vessels to sail all the way into Manchester and the city became an important seaport.
Where the Canals Crossed
That was all fascinating although the stories of two specific two canals didn’t differ materially from many of the dozens of other English canals. However the two canals crossed physical paths and that was where things got interesting. Engineers had to find a unique solution to accommodate the situation. The Bridgewater Canal, being the older structure, crossed above the River Irwell on an historic stone arched aqueduct at the town of Barton-on-Irwell. Oceangoing ships on the new Manchester Canal, following the path of the River Irwell, would never be able to fit beneath the aqueduct. It had to be demolished. In its place rose a marvelous manifestation of Victorian design, a swing aqueduct.
The Barton Swing Aqueduct became the first and possibly the only structure of its type anywhere in the world. It was designed to pivot 90 degrees whenever large ships traveling along the Manchester Canal approached it, allowing them to pass without obstruction. Engineers created an artificial island at the center of the canal that served as the pivot point. A control tower built on the island contained the necessary machinery to operate the swing. Some of process involved manual labor as evidenced by the YouTube video. One can see a worker operating a hand crank to move the watergate at the end of the aqueduct. The swing aqueduct is still in operation serving its original purpose, an engineering marvel.
Barton Swing Aqueduct and Bridge, Manchester, UK
I also appreciated how the feature appeared in online maps. I’d never seen a cartographic representation of a canal crossing above another canal before.
Manchester Ship Canal by Phil Beard on Flickr (cc)
In addition there was a road that crossed the Manchester Canal near the same point. It also required a swinging mechanism, and was called the Barton Road Swing Bridge. The same concrete island and control tower pivoted the road bridge at the same time it pivoted the aqueduct.
Reader "Qadgop the Mercotan" sent an email message to 12MC recently, referencing a conversation on the Straight Dope Message Board under the intriguing title, "Are there any streets with names containing all four cardinal points?" One of the participants on that board, kunilou, discovered a street that met the criteria: Southeast Circle NW in Albuquerque, New Mexico. And it appeared to run into Northeast Circle SW! (map). Many thanks to Qadgop the Mercotan for passing that along.