Wednesday, September 21, 2022

Lea Bridge, Derbyshire

Keeping the water flowing

The Cromford Canal was begun in the 1790s with the ultimate aim of linking Cromford with Manchester, giving a route to a market for the area’s mineral resources. Limestone and the lime produced from it were lucrative potential exports from the area. In addition, Richard Arkwright saw that he might use water transport to service his mills and backed the project, helping the progress of the necessary bill through Parliament and selling part of his garden at Cromford to allow a wharf to be constructed.

In the 1840s, the canal hit a problem. It had filled with water removed from lead mines in the area, but as the miners continued to remove the lead, they dug deeper and opened new underground channels to drain away the water, which no longer flowed into the canal, leaving boats stranded. The answer was a pump to remove water from the River Derwent to keep the canal topped up. But the river provided only a finite amount of water, some of which was itself used by the area’s industry. To stop the river too becoming dry, restrictions were imposed on taking water from the Derwent: water could only be pumped out for the canal between 8 pm on Saturdays and the same time on Sundays, when the local factories were not working. So they needed a pump with an unusually high capacity, to make best use of the time allowed.

Leawood Pump House, which they built to house the pump, is visually impressive. It is constructed of well worked gritstone, with chamfered ashlar quoins, classical windows, and pediment. The chimney is 95 feet high and also of stone, with a cap of cast iron. Inside is the original steam engine, built by Graham and Company of Elsecar, near Rotherham. It’s a big, single-action beam engine, still in working order, and can run at 7 strokes per minute, lifting about 4 tons of water at each stroke. This means it can shift a huge volume of water very quickly, so that the canal company could take the water they needed during the time they were given to do so. The pump house was successful, and the engine ran regularly for almost a century, until 1944 when the canal closed. It is still run occasionally, when visitors can experience the sheer power of steam. When I passed by, all was quiet, but the power of the architecture was clear to see.

No comments: