Thursday, 15 September 2011

Pump It Up
The Kennet and Avon  Canal is about 75 miles from Reading to Bath and a cross section of it shows the steady climb up from the east and the impact of the Caen Hill flight of locks at Devizes.
Water supply is always an important consideration when designing a canal. From Reading to Kintbury water is supplied primarily from the River Kennet: The western section of the canal draws water from the River Avon. At various poionts on the canal these fluvial sources are augmented by back-pumping, particularly at Caen Hill where the electric pump at Foxhanger can raise a lock full of water to the top of the flight every 11 minutes. In the past pumps were not electric.

Crofton was powered by steam supplied by two Lancashire boilers. These are run about once a month during the summer for tourists to view.
Last year, however, the modern electric pump failed and Crofton Steam Pumping Station came into its own by  fulfilling its original role.

Restoration of the Crofton pump was undertaken by the Kennet & Avon Canal Trust but these plaques remind us of the immense debt we owe to Sir John Smith and his Manifold Trust.
Sir John, who also foounded The Landmark Trust, was also instrumental in bringing Brunel's SS Great Britain hack to Bristol from the Falklands where it was rusting awy. A great man, who I had the priviledge of meeting, and who achieved much without seeking glory for himself.

At Claverton, near Bath, a very neat solution was employed which has overtones of the search for perpetual motion:

The water was lifted from the River Avon to the canal by a waterwheel powered by the River Avon itself.

This suffered from inundation whenever the river  was in flood and is no longer operational although the mechanism is run by electric power on open days.

About half way down the Widcombe flight of locks which take the canal down into the Avon at Bath is what many passersby think is a monument of some kind.  It is the remaning chimney  from a pumping station which used to porvide back-pumping for the flight.

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