“The success of wells, penetrating deep into large subterranean basins, upon the first completion, has usually led to their duplication at other points within the same basin, and the flow of the first has often been materially checked upon the commencement of flow in the second, and both again upon the commencement of flow in a third, though neither was within one mile of either of the others. The flow of the famous well at Grenelle was seriously checked by the opening of another well at more than three thousand yards, or nearly two miles distant.”
POLLUTION OF WELL WATER.
It is stated that about fifteen millions of the British population live in towns and urban districts. Even if we assume, which is not yet the case, that all these people are supplied by water-works, the remaining twelve millions of county population derive their water almost exclusively from shallow wells, and these are, so far as our experience extends, almost always horribly polluted by sewage and by animal matter of the most disgusting origin.
As the contents of the water-hole or well are pumped out, they are immediately replenished from the surrounding disgusting mixture, and it is not therefore very surprising to be assured that such wells do not become dry even in summer. Unfortunately, excrementitious liquids, especially after they have soaked through a few feet of porous soil, do not impair the palatability of water; and this polluted liquid is consumed from year to year without a suspicion of its character.
Our acquaintance with a very large portion of this class of potable waters, has been in consequence of the occurrence of severe outbreaks of typhoid fever amongst consumers of this character of water.
“The samples of water from deep unpolluted wells were obtained from wells or bore-holes of a depth rarely less than 100 feet, and reaching in one case 1,285 feet. In many cases these wells were partly or wholly supplied by surface-polluted water. Such water, when it penetrates only to shallow wells still retains a considerable proportion of its polluting organic matter in an unoxidized condition: but when it descends through one hundred feet or upwards of porous soil or rock, the exhausted filtration to which it has been subjected in passing downwards through so great a thickness of material, and the rapid oxidation of the dissolved organic matters in a porous and aerated medium, afford a considerable guarantee that all noxious constituents have been removed.”—(Rivers Pollution Commission, 1874.)
“Deep wells may become polluted, either by admission of soakage from the superficial strata into the shaft of the well, or by access of polluted water through open fissures in the rock in which the well is sunk.”—(Rivers Pollution Commission, 1874.)
“Even where wells are sunk to great distance (one was sunk at Bondy, near Paris, to a depth of 247 feet), the surrounding soil is not free from danger of pollution by the soaking of the foul liquid into the side of the well.”—(Fifth report Massachusetts State Board of Health.)
The following table shows the average analysis of ten worst examples of well water (parts in 100,000 parts):
| AV. DEPTH. | CARBON ORGANIC. | NITROGEN ORGANIC. | CHLORINE. | HARDNESS. | |
| Shallow wells, | — | 1.560 | .241 | 16.56 | 63.24 |
| Deep wells polluted, | — | .363 | .092 | 9.45 | 36.27 |
| Deep wells unpolluted, | 380 | .151 | .032 | 14.14 | 27.4 |