At the beginning of the 18th Century Lancaster was a prosperous town with numerous small tradesmen who, by the end of the century, were calling themselves ‘merchants’ and were dealing with the West Indies and the Baltic. Increasingly, from the middle of the century, wealth was accrued from the now infamous slave trade.
The River Lune was always difficult to navigate and trade was being lost to Liverpool. The initial proposal was for a canal to link Lancaster with Kendal and Preston and then on to join the Leeds and Liverpool canal.
In 1782 the design was entrusted to James Brindley but this was to prove to be the year of his death and the route was surveyed by his assistant Robert Whitworth. This was to be abandoned in favour of building a dock at Glasson, which was completed in 1787.
The idea of a canal was later revived and in 1790 John Rennie was asked to re-survey the route. The new proposals were not based on trade with the Americas but were to transport coal from the South Lancashire coalfield and limestone from the quarries around Kendal to the north. This trade later earnt the canal the nickname “The Black and White”. Poor roads at the time meant that it was uneconomical to transport coal more than about 12 miles. The proposal was for a broad canal which would ultimately link with the Bridgewater. This ambitious scheme would eventually involve the construction of 225 road bridges, 22 aqueducts and tunnels at Whittle Hills and Hincaster. Major undertakings would be the aqueducts over the River Lune and the River Ribble.
A Parliamentary Bill was promoted on the scheme prepared by Rennie in January 1792 and despite objections to the route, raised by the Leeds and Liverpool, contracts were placed for the first phase, Ellel to Tewitfield later that year. The speed of progress was incredible and by 1795 over 1,000 men were working on the route with resident engineers, Archibald Millar for north of the Ribble and Henry Eastburn the south.
The bridges are of locally won stone masonry and designed with curved abutments to resist horizontal forces. . Interestingly Rennie favoured brick for the Lune aqueduct on cost grounds but was overruled by the promoters who favoured stone. There is a degree of standardisation but with each bridge designed for the specific location. The Rennie trademark was for robust, well-engineered structures but he was highly innovative. The aqueduct over the River Calder at Catteral, where the river and the canal are at similar levels, incorporates a weir and inverted syphon.
Innovation extended to the construction of the swing bridges where ball bearings were used to ease the motion, as he had first used on the Kennet and Avon. This must have been a huge boon as previously these bridges needed to be worked by the barge horses.
The quality of construction is constant throughout and Cyril Boucher, Rennie’s biographer, describes the Lune Aqueduct as possibly the finest bridge in the country.
By 1797 the canal was open between Preston and Tewitfield and by 1799 the southern section had been extended from Wigan to Johnson’s Hillock, just south of Preston. To complete the link was the construction of the Ribble Aqueduct together with a long flight of locks. By then the financial resources of the canal company were severely stretched, not least by the cost of the Lune aqueduct , and alternative schemes were considered such as a tram road. William Jessop was appointed to work with Rennie to appraise these proposals. In the event, the two went on to advise on the final scheme, this being a tram road worked with stationary steam engines. The route involved the construction of Whittle Hills tunnel to a Rennie design.
In the meantime Rennie had produced a design for a link to the Glasson Dock involving the construction of seven locks, although this was not opened until after his death.
Similarly, the final connection to Kendal, with eight locks, was not completed until 1819. This deviated from Rennie’s route however bridges are to his designs. The engineer for the upper section was William Crossley, the son of Rennie’s former engineer.
Rennie’s grand works can be readily appreciated not least by taking the walk up the route of the old railway from Lancaster to the Lune aqueduct. Possibly less well-known but interesting examples of his works are in the environs of the short Walton Summit branch.