Result of inquiries as to quantities of water required per acre for irrigated lands : and the supply of sewage obtainable from the metropolis. May, 1849.

  • London (England). Metropolitan Commission of Sewers.
Date:
[1849]
Catalogue details

Licence: Public Domain Mark

Credit: Result of inquiries as to quantities of water required per acre for irrigated lands : and the supply of sewage obtainable from the metropolis. May, 1849. Source: Wellcome Collection.

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    Rough Proof. | iftletropolitan fsetoers. SEWAGE MANURE COMMITTEE. Result of some Inquiries upon the Amount of Water required per Acre by Irrigated Meads, and the Supply obtainable from the Sewers of the Metropolis, Ordered to be printed, 21s£ Map, 1849. It is pretty certain tliat the liquid manure of the London Sewers is not sufficiently concentrated to be extensively applicable for the use of the cultivator of arable soil in the immediate neighbourhood of London, or of the market gardener. To this fact, in the case of the Westminster Sewers, the evidence of the London Sewage Manure Company appears to concur with that of several others. We can, then, perhaps, only reasonably look to water meads for the profitable and sufficiently extensive consumption of the sewage of the Metropolitan Districts. For this pur¬ pose we may safely regard its value to be undoubted. It is essential, however, for their sufficiently extensive employment,— 1. That the sewage shall be raised from the sewers by powerful engines. 2. That it shall be carried in convenient pipes or channels to a considerable distance from thickly-populated places. 3. That the districts where it shall be thus used in irrigated meadows should be extensive, and possess a suitable soil for the construction of water meads. 4. It is desirable that such meads should be constructed on unequal eleva¬ tions, so as to allow of the irrigating fluid being readily used a second time, as in the new meads at Edinburgh (see Mr Buchanan’s Report, post, p. 6). In calculating the probable value of the sewage of towns to the citizen and to the irrigator, it may be useful to endeavour to form some estimate, however imper¬ fect, of the quantity of liquid required for the irrigation of a given extent of land. This, it is true, can only be accurately determined by the examination of the soil upon which the irrigating water is allowed to flow, as the amount is not only influ¬ enced by the composition of the surface soil, but also by the more or less porous nature of the substratum on which it rests. [See Report of Mr Buchanan, post, p. 6.) It is indeed evident that the immediate soakage from an irrigated soil which iests on a porous sand, for instance, will be rapid, whilst from the same kind of soil with an understratum of clay the filtration will be much slower. Hence it is certain that the stream of water sufficiently copious for the rapid irrigation of one kind of soil would be too quickly absorbed by the porous substratum of another, to allow of its diffusion over the surface soil with the same, or perhaps sufficient rapidity. (No. 36)