Posted by John W on June 12, 1998 at 02:42:02:
In response to Water Supply, written by Captain Everett on June 11, 1998 at 21:58:49
It may be of interest to know that London actually floats on a pool of water contained by the London blue clay below. The original form of the terrain was a wide marshy valley broken by a few islets of gravel and laced with multiple streams. These rivulets are now culverted under the city--cf Holborn--the Hollow Bourne or Stream and Fleet Street after the Fleet river--and the Thames runs between its confining embankments. You can see the great swinging iron flaps which let the water from these streams into the river, in the embankment,from a boat.
So in the original city down by the river you could sink a shallow well and find water of a sort. The Bank of England has its own . However this ground water was soon polluted and clean drinking water became a problem. Hence the schemes to tap clean springs in the hills above and bring water to the town. For the poor however polluted groundwater pumped up locally was the resource. The Broad Street Pump case, when a pioneering doctor made the connection between epidemic disease and water by plotting the incidence around the pump, at a time when the conventional wisdom blamed miasmas in the air, is a graphic illustration of the problem. Interestingly, a current plot of pulmonary disease in London reveals that the pattern is influenced by the underground streams which still flow in culverts underground or filter through the gravel beds on which the lower parts of the city rest.
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