The genius of Sir John Hawkshaw at Burrs and Elton

During the late Victorian period, the name of Sir John Hawkshaw (1811-91) blazed as brightly as that of any of any other great engineer who had become a household name; in an age when heroic status was rightly granted for human triumph over natural forces.  His many works included a section of the London Underground, the docks at Penarth and Holyhead, the Amsterdam Ship Canal, and the first Severn Tunnel.

Figure 1. Eminent Victorian engineer Sir John Hawkshaw.

But his speciality was railway and canal engineering, and from 1847 onwards, he was chief engineer to the Lancashire and Yorkshire Railway (LYR).  In the 1880s, when a decision was taken to upgrade the LYR’s Manchester, Bolton & Bury Canal, he took a close look at the infrastructure, including the canal feeder from Burrs to Elton, and made a bold decision.  He wouldn’t mess about buying and cutting local stone at great cost; instead he bought in several million of the newly-developed Staffordshire blue engineering bricks from the Potteries, and applied these to the task in hand.

Figure 2. Aquaduct in form of gravity dam, carrying canal feeder across the valley of the Elton Brook.

Hawkshaw’s most massive work was at the heart of Elton, and this is so large that it is almost impossible to view the whole feature from any single point. It carries the canal feeder across the mouth of the valley of the Elton Brook, spanning between Wood Street and Ainsworth Road. It comprises an aquaduct in the form of a gravity dam; as a linear arcade of massive blind arches rising to a height of over 7m, behind the old gasworks site (now occupied by Wynsors and Lidl).  Although impressive when viewed close up, it is not possible to see the scale of the buried foundations, nor to view the reverse face, with its huge ‘counterforts’, concealed deeply after Mucklow’s Elton Fold Works was demolished and the valley here infilled.

Figure 3. Course of canal feeder between Wood Street and Ainsworth Road, 1890.

All visitors to Burrs will be familiar with the canal feeder aquaduct which stands just upstream from Burrs Bridge.  This was originally raised in stone during the 1790s, but was later rebuilt using Staffordshire blues under Hawkshaw’s control.  The visible brickwork conceals a thick, waterproof trough of puddled clay, which is itself sandwiched and supported by an outer U-shaped lining of Blue Lias lime cement.      

Figure 4. Burrs Aquaduct carrying canal feeder over river Irwell, in 1990.

And when Hawkshaw replaced the original rock-cut channel at Burrs Weir, he did so on the largest possible scale, again using blue Staffordshire brickwork.  No less than four sluice gates were installed here, which would provide guaranteed water regulation to the mills at Burrs and Calrows, and to Elton reservoir, even if two or three sluices were blocked or inoperative. This provision of ‘engineering redundancy’ was critical in an age when mercantile trade was always considered as a ‘life or death’ matter.

Figure 5. Bank of four sluice gates at Burrs Weir. Only the middle pair can be actively controlled, the other two have no mechanisms.

But Hawkshaw also built in a ‘fail safe’ device, in the event that one or more sluices could not be sealed, which is exactly what happened in March, August, and November 2019.  Within the feeder bank, about 60m downstream from the sluices, is a timber penstock paddle with a disused ‘rack & pinion’ mechanism.  This paddle seals a massive iron pipe, which leads straight back to the river, and if in good repair, could quickly be opened to discharge a great volume of water back to the river, to prevent any downstream flooding.

Figure 6. Sluice retaining wall at Burrs Weir. The redundant flooding discharge pipe is concealed within the vegetation on the wall face, to left of centre.

Unfortunately, this byewash sluice has been neglected and disused for decades, and for the sake of perhaps £100 worth of timber to form a new sliding paddle, footpaths have been washed away, the Lamppost café flooded, and the pipe bridge northern abutment voided of the bedding which underlies the flags.

Figure 7. ‘Rack & pinion’ mechanism and upper part of discharge penstock just visible (bottom left), in canal feeder bank, downstream from Burrs Weir sluice gates.

Now as global warming results in ever more frequent and ferocious flooding, it is more important than ever to maintain the water-control infrastructure at Burrs.  I wouldn’t expect that anyone presently charged with responsibility for Hawkshaw’s legacy would exhibit the sort of boldness and vision displayed by the great engineer, but it must surely at some point become blatantly obvious that if you choose not to maintain these critical structures, then it will cost far more in downstream flood-damage repairs when sluice gates begin to decay and collapse.  Hardly rocket science, is it?

Figure 8. Impressive but uncontrolled cascade at the pipe bridge, hydraulic pressure voided the bedding of the flags behind the abutment. November 2019.

(NOTE: A ‘counterfort’ is a buried buttress, usually located on the landward side of a dock wall or retaining wall, to prevent any rotational movement caused by lateral pressures.)

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