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“Section shewing the cause of the rise of water in Artesian Wells in the basin of London” from William Buckland, 'Geology and mineralogy considered with reference to natural theology'. London: William Pickering. (1836). GSL Library collections.
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Not all of the water needed for London’s inhabitants was supplied by the Statutory Water Companies. Large numbers of manufactories, breweries and other organisations (including the fountains in Trafalgar Square) which required water in large quantities sank their own wells. During the first half of the 19th century there were two types of wells. Shallow wells, which received surface drainage, were mainly used for drinking water but they were susceptible to contamination from the surrounding soil as happened to the one connected to the Broad Street Pump. The second were deeper wells, sunk through London’s Tertiary strata increasingly into the Chalk below.
The earlier deep wells had to be of great diameter in order to facilitate the pumping plant, but the use of narrower artesian wells, which rely on hydrostatic pressure which forces the water to the surface, became increasingly popular. These wells have been sunk for millennia but get their name from the French region of Artois where their use was known from the Middle Ages.
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L - 'Section of the well sunk at the Bank of England, 1851', by Standidge & Co, 1852. Archive ref: LDGSL/447. This geological section, given to the Society by Robert Mylne and therefore presumably one of his water engineering works, is of the artesian well which was drilled beneath the Bank of England in 1851. Click to enlarge.
R: ‘Account of wells at Chiswick and Hammersmith’, [?1822-1830] Archive ref: LDGSL/3/25.
Some artesian wells were purely domestic. This charming account tells of a Mr Brook from Hammersmith who decided to drill his own artesian well in his garden but which produced a jet of water so strong that it flooded his newly built house. He lived in the aptly named ‘Spring Cottage’. Click to enlarge.
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Chalk’s important role as an aquifer had long been recognised, for instance the original source of the water supply of the New River Company was from the Chalk springs of the Chadwell and Amwell.
However although Chalk is extremely absorbent, holding about 2 gallons of water per cubic foot, it does not give up its water content easily. Instead extraction relies on the water pooling in the random joints, fractures and fissures which traverse its strata. These fractures are more abundant when the Chalk is nearer the surface (unconfined) rather than covered by the Tertiary beds of London (confined). One such place nearby London was the Chiltern Hills.
Chalk Wells on an Industrial Scale
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Geological map of the South East of England, from Samuel Collett Homersham, 'Report to the Directors [of the] London (Watford) Spring-water Company', 3rd edition (1850). Tracts: E Tracts 30.
The section is copied from William Buckland's 1836 image above. Click to enlarge. |
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“Section of the experimental well at Bushey Meadows, Herts (1840)", from Samuel Collett Homersham, 'Report to the Directors [of the] London (Watford) Spring-water Company', 3rd edition (1850). Tracts: E Tracts 30. Click to enlarge.
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The London (Watford) Spring-water Company was formed as a consequence of the series of reports from the Board of Health on the state of London’s water supply in 1850. Although it was to be another privately run water company, the London (Watford) Spring-water Company (as indicated in its name) was to obtain its water supply not from the Thames but from Bushey Meadows, in the valley of the Colne north of Watford. This area was described as being “surrounded on the north, north-west, west and south-west by almost bare chalk hills varying from 500 to 900 feet in altitude” under which at a relatively short depth of 100-200 feet could be found large faults, fissures and cavities filled with water which when tapped “rapidly ascends to within a few inches of the surface although the ground itself is 169 feet above the Trinity Water high-water mark”. [Homersham (1950), pp4-5]
The idea of extracting groundwater from relatively shallow wells sunk into the Chilterns actually derived from the 1840-1841 reports made by the civil engineer Robert Stephenson, FGS, (1803-1859) for another fledgling water company. The proposed London and Westminster Water Company had similarly planned on setting up a rival service to the inhabitants on the north side of the Thames who were currently served by the existing water companies.
Stephenson described how the water, when filtered through the Chalk, was “entirely divested of all impurities” and was so clear that he could see the bottom of the well despite it being thirty feet deep [Stephenson (1841), p23]. However this seemingly perfect source in the confined Chalk that sat beneath the London Clay of the Capital would not be able to be recharged easily and was therefore unsuitable for water extraction on an industrial scale, hence the focus on the Chiltern Hills.
The local mill-owners objected to the plan as they believed that extracting water in the vast quantities required would affect the springs which fed the mill-streams which powered their works. In resurrecting the idea, Samuel Homersham, engineer to the London (Watford) Spring-water Company contended that the water from these springs derived from the upper stratum of the Chalk and that the planned wells would be sunk much lower, and thereby would not affect their supply.
Either way it did not matter as the bill to establish the London (Watford) Spring-water Company as a statutory water company was rejected by Parliament in 1853, the preference to concentrate on regulating the existing suppliers rather than introducing more competition.
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