Bridgewater Canal - Design and Construction

Design and Construction

Francis Egerton, 3rd Duke of Bridgewater, owned some of the coal mines dug to supply north west England with fuel for the steam engines instrumental in powering England's industrial revolution. The Duke transported his coal along the Mersey and Irwell Navigation and also by packhorse, but each method was inefficient and expensive; river transport was subject to the vagaries of river navigation, and the amount of coal packhorses could carry was limited by its relative weight. The Duke's underground mines also suffered from persistent flooding, caused by the geology of the Middle Coal Measures, where the coal seam lies beneath a layer of permeable sandstone.

Having visited the Canal du Midi in France and watched the construction of the Sankey Canal in England, the Duke's solution to these problems was to build an underground canal at Worsley, connected to a surface canal between Worsley and Salford. In addition to easing overland transport difficulties and providing drainage for his mines, an underground canal would provide a reliable source of water for the surface canal, and also eliminate the need to lift the coal to the surface (an expensive and difficult proposition). The canal boats would carry 30 long tons (30 t) at a time, pulled by only one horse–more than ten times the amount of cargo per horse that was possible with a cart. The Duke and his estate manager John Gilbert produced a plan of the canal, and in 1759 obtained an Act of Parliament, enabling its construction.

James Brindley was brought in for his technical expertise (having previously installed a pumping system at the nearby Wet Earth Colliery), and after a six-day visit suggested varying the route of the proposed canal away from Salford, instead taking it across the River Irwell to Stretford and thereon into Manchester. This route would make connecting to any future canals much easier, and would also increase competition with the Mersey and Irwell Navigation company. Brindley moved into Worsley Old Hall and spent 46 days surveying the proposed route, which to cross the Irwell would require the construction of an aqueduct at Barton-upon-Irwell. At the Duke's behest, in January 1760 Brindley also travelled to London to give evidence before a parliamentary committee. The Duke therefore gained a second Act of Parliament, which superseded the original.

Brindley's planned route began at Worsley and passed southeast through Eccles, before turning south to cross the River Irwell. From there it continued southeast along the edge of Trafford Park, and then east into Manchester. Although a connection with the Mersey and Irwell Navigation was included in the new Act, at Hulme Locks in Castlefield (on land previously occupied by Hulme Hall), this was not completed until 1838. The terminus would be at Castlefield Basin, where the nearby River Medlock was to help supply the canal with water. Boats would unload their cargoes inside the Duke's purpose-built warehouse. There were no locks in Brindley's design, demonstrating his ability as a competent engineer. His aqueduct was built relatively quickly for the time; work commenced in September 1760 and the first boat crossed on 17 July 1761.

The Duke invested a large sum of money in the scheme. From Worsley to Manchester its construction cost £168,000 (£23,997,480 as of 2012), but its advantages over land and river transport meant that within a year of its opening in 1761, the price of coal in Manchester fell by about half. This success helped inspire a period of intense canal building, known as Canal Mania. Along with its stone aqueduct at Barton-upon-Irwell, the Bridgewater Canal was considered a major engineering achievement. One commentator wrote that when finished, " will be the most extraordinary thing in the Kingdom, if not in Europe. The boats in some places are to go underground, and in other places over a navigable river, without communicating with its waters ..."

In addition to the Duke's warehouse at Manchester, more buildings were built by Brindley and extended to Alport Street (now called Deansgate). The warehouses were of timber frame design, with load-bearing hand-made brick walls, supported on cast iron posts. The Duke's warehouse was badly damaged by fire in 1789 but was rebuilt.