London Labour and the London Poor, volume 2
Of the New Plan of Sewerage.
THIS branch of the subject hardly forms part of my present inquiry, but, having pointed out the defects of the sewers, it seems but reasonable and right to say a few words on the measures determined upon for their improvement. It is only necessary for me, however, to indicate the principal characteristics of the new, or rather intended, mode of sewerage, as the work may be said to have been but commenced, or hardly commenced in earnest, the Report of Mr. Frank Forster (the engineer) bearing the date of .
In the carrying out of the engineer's plan— which from its magnitude, and, in all human probability, from its cost, when completed, would be in other countries, but is here only —in the carrying out of this scheme, I say, remarkable changes will be found. The is the employment of the power of steam in sewerage; the other is the diversion of the sewage from the current of the Thames. The ultimate uses of this sewage, agriculturally or otherwise, form no part of the present consideration.
I should, however, enumerate the general principles on which the best authorities have agreed that the London sewers should be constructed so as to ensure a proper disposal of the sewage, for these principles are said to be at the basis of Mr. Forster's plan.
I condense under the following heads the substance of a mass of Reports, Committee Meetings, Suggestions, Plans, &c.:—
. The channels, or pipeage, or other means of conveying away house-refuse, should be so made that the removal will be , more especially of any refuse or filth capable of suspension in water, since its immediate carrying off, it is said, would leave no time for the generation of miasma.
. Means should be provided for such disposal of sewage as would prevent its tainting any stream, well, or pool, or, by its stagnation or obstruction, in any way poisoning the atmosphere. And, as a natural and legitimate result, it should be at the most economical rate.
. In the providing works of deposit or storage in low districts, or "of discharge where the natural outlets are free," such works should be provided as would not subject any place, or any man's property, to the risk of inundation, or any other evil consequence; while in the construction of the drainage of the substratum, the works should be at such a depth below the foundation of all buildings that tenements should not be exposed to that continued damage from exhalation and dampness which leads to the dry rot in timber, and to an immature decay of materials and a general unhealthiness.
There are other points insisted upon in many Reports to which I need but allude, such as
() The channels containing sewage should be of enduring and impermeable material, so as to prevent all soakage.
() There should be throughout the channels of the subterranean metropolis a fall or inclination which would suffice to prevent the accumulation of any sewage deposit, with its deleterious influence and ultimate costliness.
() Similar provisions should be used were it but to prevent the creation of the noxious gases which now permeate many houses (especially in the quarters inhabited by the poor) and escape into many streets, courts, and alleys, for until improvements are effected the pent--up sewage and the saturated brickwork of the sewers and older drains must generate such gases.
() No tidal stream should ever receive a flow of sewage, because then the cause of evil is never absent, for the filth comes back with the tide; and as the Thames water constitutes the grand fount of metropolitan consumption, the water companies, with very trifling exceptions, give us back much of our own excrement, mixed with every conceivable, and sometimes noxious, nastiness, with which we may brew, cook, and wash—and drink, if we can. Filtering remedies but a portion of the evil.
Now it would appear that not of these requirements, the necessity of which is unquestioned and unquestionable, is fully carried out by the present system of sewerage, and hence the need of some new plan in which the defects may be remedied, and the proper principles carried out.
The instructions given by the Court were to the following effect:—
A. The Thames should be kept free from sewage whatever the state of the tide.
B. There should be intercepting drains to carry off the sewage (so keeping the Thames unsoiled by it) wherever practicable.
C. The sewage should be raised by artificial means into a main channel for removal.
D. The intercepting sewers should be so constructed as to secure the largest amount of effective drainage without artificial appliances.
In preparing his plan, Mr. Forster had the advice and assistance of Mr. Haywood, of the City Court of Sewers.
The metropolis is divided into portions— "the northern portion of the metropolis," or rather that portion of the metropolis which is on the north or Middlesex bank of the Thames; and the southern portion, or that which is on the south or Surrey side of the river.
The northern portion is in the new plan considered to "divide itself into separate areas," and to these areas different modes of sewerage are to be applied:
The district runs from Holsden-green (beyond the better-known Kensall-green) in the west, to the Tower Hamlets in the east. Its form is irregular, but not very much so, merely narrowing from Westbourn-green to its western extremity, the country then becoming rural or woodland. Its highest reaches to the north are to Highgate and Stamford-hill. The nearest approach to the south is to a portion of the Strand, between Charing-cross and . Care has evidently been taken to skirt this district, so to speak, by the canals and the railroads. This division of the northern portion is described as "the district for natural drainage."
The area of this division is about / square miles.
The division meets the at the highway separating Kensington-gardens from Bayswater; and runs on, bordering the river, all the way to the West India Dock. Its shape is irregular, but, abating the roundness, presents somewhat of that sort of figure seen in the instrument known as a dumb-bell, the narrowest or handpart being that between Charing-cross and Drurylane, skirting the river as its southern bound. At its eastern end this district widens abruptly, taking in Victoria-park, , and .
The area of this division of the northern portion is / square miles.
There are, moreover, small tracts, comprising the southern part of the , and a narrow slip on the west side of the river Lea, which are intended to allow the rainfall to run into the Thames and the Lea respectively.
The area of the is square mile.
The area to be drained by natural outfall comprises, then, / square miles as regards rainfall, and the same extent as regards sewage; while the area to the drainage of which steam power is to be applied comprises / square miles of rainfall, and / square miles of sewage; the united areas of rainfall and sewage respectively being and / square miles.
The length of the great "high-level sewerage" will be, as regards the main sewer, miles and yards; that of the "low-level sewerage," miles and yards.
I will now describe the course of each of these constructions.
On the eastern bank of the Lea the sewage of both districts is to be concentrated. The highlevel sewer will commence and the Lea near the " Mills." It is then to proceed "in a westerly direction under the East and West India Dock Railway and the Extension Railway, beneath the Regent's-canal, to the east end of the Bethnal-green-road, at the crossing of the Cambridge-heath-road, at which point it will be joined by the proposed northern division of the Hackney-brook, which drains an extensive district up to the watershed line north of London, including Hackney, Stoke and Holloway, and part of Highgate and Hampstead; from thence the main sewer proceeds along the Bethnalgreen-road, , , Wildernessrow (where a short branch from will join) to Brook-street-hill; from thence to Little , where a distance of about yards is proposed to be carried by an aqueduct over the Fleet-valley; thence along , at the end of which it will receive a branch from , on the south side, and a diversion of the Fleet-river, on the north side; thence along Theobald's-road, , , , to Rathbone-place (where it will receive a diversion of the sewer from Park-crescent), along , and extending thence across Regent-circus to (where it will intercept the King's Scholars' Pond sewer), continuing still along to Bayswater-place, Grand Junctionroad, Uxbridge-road, where it is joined by the Ranelagh sewer, the sewage of which it is capable of receiving, and at this point it terminates."
It is difficult to convey to a reader, especially to a reader who may not be familiar with the localities of London generally, any adequate notion of the largeness, speaking merely of extent, of this undertaking. Even a map conveys no sufficient idea of it.
Perhaps I may best be able to suggest to a reader's mind a knowledge of this largeness, when I state that in the district I have just described, which is but portion (although the greatest) of the sewerage of but side of the Thames, more than half a million of persons, and nearly houses are, so to speak, to be sewered.
The low-level tract sewerage, also, concentrates on the Lea, "near to Mill's distillery, taking the north-western bank of the , at which point it receives the branch intended to intercept the sewage of the ; thence continuing along the bank of , through a portion of the Commercial-road, Brookstreet, and beneath the Sun Tavern Fields, into , or Upper ; thence along Ratcliffe-highway and Upper , across , through Little and Great Towerstreets, , , Little and , , Old Fishstreet, and Little Knight Rider-street; thence beneath houses in Wardrobe-terrace, and on the eastern side of St. Andrew's-hill, along Earlstreet to Blackfriars--road. From it is proposed to construct the sewer along the river shore to the junction of the Victoriastreet sewer at Percy-wharf; which sewer between Percy-wharf and Shaftesbury-terrace, , becomes thus an integral portion of the intercepting line; at , , a branch from the sewer is intended to proceed along Abingdon and Millbank-streets, as far as and for the purpose of taking up the King's Scholars' Pond and other sewers at their outlets into the Thames. From Shaftesburyter- race the sewer is proposed to be extended through and along the King's-road, , to Park-walk, intercepting all the sewers along its line, and terminating at a point where the drainage of Kensington may be brought into it without pumping."
The lines of sewerage thus described are, then, all to the of the Lea, and all, whether from the shore of the Thames, or the northern reaches in Highgate and Hampstead, converging to a pumping station or sewage-concentration, on the bank of the Lea, in . By this new plan, then, the high-level sewer is to the Lea, but that arrangement is impossible as respects the district described, which is the level of the Lea, so that its course is to be that river, a little below where it is crossed by the high-level line. To dispose of the sewage, therefore, conveyed from the low-level tract, there will be a sewer of a "depth of feet " the invert of the high-level sewer. This sewer, then, at the depth of feet, will run to the point of concentration containing the low-level sewage.
At this point of the works, in order that the sewage may be collected, so as to be disposed of ultimately in mass, it has to be from the low to the high-level sewer. The invert of the high-level sewer will at the lifting or pumping station be feet the ordnance datum, while that of the low-level sewer will be feet the same standard. Thus a great body of metropolitan sewage, comprising among other districts the refuse of the whole City of London, must be lifted no less than feet, in order to be got rid of along with what has been carried to the same focus by its natural flow.
The lifting is to be effected by means of steam, and the pumping power required has been computed at -horse power. To supply this great mechanical and scientific force, there are to be provided engines, each of -horse power, with a engine of equal capacity, to be available in case of accident, or while either of the other engines might require repairs of some duration.
The northern sewage of London (or that of the Middlesex bank of the Thames, covered by that division of the capital) having been thus brought to a sort of central reservoir, or meeting point, will be conveyed in parallel lines of sewerage to the bank of the river Roding, being the eastern extremity of Gallion's Reach (which is below Woolwich Reach), in the Thames. The Roding flows into the Thames at Barking Creek mouth. The length of this line will be miles.
The whole of the sewage and rainfall, then, will be thus diverted to destination, instead of being issued into the river through a multiplicity of outlets in every part of the northern shore where the population is dense, and will be carried into the Thames at Barking Creek, unless, as I have intimated, a market be found for the sewage; when it may be disposed of as is most advantageous. The only exceptions to this carrying off will be upon the occurrence of long-continued and heavy rains or violent storms, when the surplus water will be carried off by some of the present outlets into the river; but even on such occasions, the or cleansings of the sewerage will be conveyed to the main outlet at the river Roding.
The inclination which has been assigned to the whole of the lines of sewers I have described, is, with some unimportant exceptions, feet per mile, or in . These new sewers are, or rather will be, calculated to carry off a fall of rain, equal to inch in hours, in addition to the average daily flow of sewage.
Mr. Forster concludes his Report:—"I am only able to submit approximately that I estimate the cost of the whole of the lines of sewers, the pumping engines, and station, the reservoir, tidal gates, and other apparatus, at million and (). This estimate does not include the sums required for the purchase of land and houses, which may be needed for the site of the pumping engine-house, or compensation for certain portions of the lines of sewers."
As regards the improvements in the sewerage on the south side of the Thames (the great fever district of the metropolis, and consequently the most important of all, and where the drainage is of the worst kind), I can be very brief, as nothing has been positively determined.
A somewhat similar system will be adopted on the south side of the Thames, where it is proposed to form main intercepting sewer; but, owing to the physical configuration of this part of the town, none of the water will flow away entirely by gravitation. There will be a pumping station on the banks of the Ravensbourne, to raise the water about feet; and a pumping station to raise the water from the continued sewer in the reservoir, in Woolwich Marsh, which is to receive it during the intervals of the tides. The waters are to be discharged into the river at the last-named point. The main sewer on the south side will be of nearly equally colossal proportions; for its total length is proposed to be about miles furlongs, including the main trunk drain of about miles long, and the respective branches. The area to be relieved is about proportionate to the length of the drain; but the steam power employed will be proportionally greater upon the southern than upon the northern side.
There are divers opinions, of course, as to the practicability and ultimate good working of this plan; speculations into which it is not necessary for me to enter. Mr. Forster has, moreover, resigned his office, adding another to the many changes among the engineers, surveyors, and other employás under the Metropolitan Commission; a fact little creditable to the management of the Commissioners, who, with exception, may be looked upon as irresponsible.