Of the London Street-Drains.
We have as yet dealt only with the means of removing the liquid refuse from the houses of the metropolis. This, as was pointed out at the commencement of the present subject, consists principally of the 19,000,000,000 gallons of water that are annually supplied to the London residences by mechanical means. But there still remain the 5,000,000,000 gallons of surface or rain-water to be carried off from the 1760 miles of streets, and the roofs and yards of the 300,000 houses which now form the British metropolis. If this immense volume of liquid were not immediately removed from our thoroughfares as fast as it fell, many of our streets would not only be transformed into canals at certain periods of the year, but perhaps at all times (except during drought) they would be, if not impassable, at least unpleasant and unhealthy, from the puddles or small pools of stagnant water that would be continually rotting them. Were such the case, the roads and streets that we now pride ourselves so highly upon would have their foundations soddened. “If the surface of a road be not kept clean so as to admit of its becoming dry between showers of rain,” said Lord Congleton, the great road authority, “it will be rapidly worn away.” Indeed the immediate removal of rain-water, so as to prevent its percolating through the surface of the road, and thereby impairing the foundation, appears to be one of the main essentials of road-making.
The means of removing this surface water, especially from the streets of a city where the rain falls at least every other day throughout the year, and reaches an aggregate depth of 24 feet in the course of the twelvemonth, is a matter of considerable moment. In Paris, and indeed almost all of the French towns, a channel is formed in the middle of each thoroughfare, and down this the water from the streets and houses is continually coursing, to the imminent peril of all pedestrians, for the wheels of every vehicle distribute, as it goes, a muddy shower on either side of the way.
We, however, have not only removed the channels from the middle to the sides of our streets, but instituted a distinct system of drainage for the conveyance of the wet refuse of our houses to the sewers—so that there are no longer (excepting in a very small portion of the suburbs) open sewers, meandering through our highways; the consequence is, the surface-water being carried off from our thoroughfares almost as fast as it falls, our streets are generally dry and clean. That there are exceptions to this rule, which are a glaring disgrace to us, it must be candidly admitted; but we must at the same time allow, when we think of the vast extent of the roadways of the metropolis (1760 miles!—nearly one-half the radius of the earth itself), the deluge of water that annually descends upon every inch of the ground which we call London (38,000,000,000 gallons!—a quantity which is almost sufficient for the formation of an American lake), and the vast amount of traffic, over the greater part of the capital—the 13,000 vehicles that daily cross London Bridge, the 11,000 conveyances that traverse Cheapside in the course of twelve hours, the 7700 that go through Temple Bar, and the 6900 that ascend and descend Holborn Hill between nine in the morning and nine at night, the 1500 omnibuses and the 3000 cabriolets that are continually hurrying from one part of the town to another, and the 10,000 private carriage, job, and cart horses that incessantly perviate the metropolis—when we reflect, I say, on this vast amount of traffic—this deluge of rain—and the wilderness of streets, it cannot but be allowed that the cleansing and draining of the London thoroughfares is most admirably conducted.
The mode of street drainage is by means of what is called a gully-hole and a gully-drain.
The Gully-hole[63] is the opening from the surface of the street (and is seen generally on each side of the way), into which all the fluid refuse of the public thoroughfares runs on its course to the sewer.
The Gully-drain is a drain generally of earthenware piping, curving from the side of the street to an opening in the top or side of the sewer, and is the means of communication between the sewer and the gully-hole.
The gully-hole is indicated by an iron grate being fitted into the surface of the side of a footpath, where the road slopes gradually from its centre to the edge of the footpath, and down this grate the water runs into the channel contrived for it in the construction of the streets. These gully-grates, the observant pedestrian—if there be a man in this hive of London who, without professional attraction to the matter, regards for a few minutes the peculiarities of the street (apart from the houses) which he is traversing—an observant pedestrian, I say, would be struck at the constantly-recurring grates in a given space in some streets, and their paucity in others. In Drury-lane there is no gully-grate, as you walk down from Holborn to where Drury-lane becomes Wych-street; whilst in some streets, not a tenth of the length of Drury-lane, there may be three, four, five, or six grates. The reason is this:—There is no sewer running down Drury-lane; a contiguous sewer, however, runs down Great Wyld-street, draining, where there are drains, the hundred courts and nooks of the poor, between Drury-lane and Lincoln’s-inn-fields, as well as the more open places leading down towards the proximity of Temple Bar. This Great Wyld-street sewer, moreover, in its course to Fleet Bridge, is made available for the drainage (very grievously deficient, according to some of the reports of the Board of Health) of Clare-market. Grates would of course be required in such a place as Drury-lane, only the street is thought to be sufficiently on the descent to convey the surface-water to the grate in Wych-street.
The parts in which the gully-grates will be found the most numerous are where the main streets are most intersected by other main streets, or by smaller off-streets, and indeed wherever the streets, of whatever size, continually intersect each other, as they do off nearly all the great street-thoroughfares in the City. Although the sewers may not be according to the plan of the streets, the gully-grates must nevertheless be found at the street intersections, whether the nearest point to the sewer or not, or else the water would not be quickly carried off, and would form a nuisance.
I am informed, on good authority, both as regards the City and Metropolitan Commissions, that the average distance of the gully-grates is thirty yards one from another, including both sides of the way. Their number does not depend upon population, but simply on the local characteristics of the highways; for of course the rain falls into all the streets in proportion to their size, whether populous or half-empty localities. As, however, the more distant roads have not such an approximation of grates, and the law which requires their formation is by no means—and perhaps, without unnecessary interference, cannot be—very definite, I am informed that it may fairly be represented, that, of the 1760 miles of London public ways, more than two-thirds, “or” remarked one informant, “say 1200 miles, are grated on each side of the street or road, at distances of sixty yards.” This would give 59 gully-holes in every one of the 1200 miles of street said to be so supplied. Hence the total number throughout the metropolis will be 70,800.
The gully-drain, which is the street-drain, always presents now a sloping curve, describing, more or less, part of a circle. This drain starts, so to speak, from the side of the street, while its course to the sewer, in order to economize space, is made by any most appropriate curve, to include the reception of as great a quantity of wet street-refuse as possible; for if the gully-drains were formed in a direct, or even a not-very-indirect line, from the street sides to the sewers, they would not only be more costly, more numerous, but would, in fact, as I was told, “choke the under-ground” of London, for now the subterranean capital is so complicated with gas, water, and drain-pipes, that such a system as will allow room for each is indispensable. The new system is, moreover, more economical. In the City the gully-drains are nearly all of nine-inch diameter in tubular pipeage. In the metropolitan jurisdiction they are the same, but not to the same extent, some being only six inches.
Fifty, or even thirty years ago, the old street channels for gully drainage were costly constructions, for they were made so as to suit sewers which were cleansed by the street being taken “up,” and the offensive deposit, thick and even indurated as it often was in those days, drawn to the surface. Some few were three and even four feet square; some two feet six inches wide, and three or four feet high; all of brick. I am assured that of the extent or cost of these old contrivances no accounts have been preserved, but that they were more than twice as costly as the present method.
In all the reports I have seen, metropolitan or city—the statements of the flushermen being to the same purport—there are complaints as to the uses to which the gully-holes are put in many parts, every kind of refuse admissible through the bars of the grate being stealthily emptied down them. The paviours, if they have an opportunity, sweep their surplus grout into the gullies, and so do the scavagers with their refuse occasionally, though this is generally done in the less-frequented parts, to get rid of the “slop,” which is valueless.
In a report, published in 1851, Mr. Haywood points out the prevalence of the practice of using the gully-gratings as dustbins! A sewer under Billingsgate accumulated in a few months many cart-loads, composed almost wholly of fish-shells; and 114 cart-loads of fish-shells, cinders, and rubbish were removed from the sewers in the vicinity of Middlesex-street (Petticoat-lane); these had accumulated in about twelve months. “Reconstructing the gullies,” he says, “so as to intercept improper substances (which has been recently done at Billingsgate), might prevent this material reaching the sewers, but it would still have to be removed from the gullies, and would thus still cause perpetual expense. Indeed, I feel convinced that nothing but making public example by convicting and punishing some offenders, under clause 69 of ‘The City of London Sewers’ Act,’ will stop the practice, so universal in the poorer localities, of using the gullies as dustbins.”
The Gully-holes are now trapped—with very few exceptions, one report states, while another report intimates that gully-trapping has no exception at all. The trap is resorted to so that the effluvium from a gully-drain may not infect the air of the public ways; but among engineers and medical sanitary inquirers, there is much difference of opinion as to whether the system of trapping is desirable or not. The general opinion seems to be, however, that all gullies should be trapped.
Of the City gully-traps, Mr. Haywood, in a report for the year 1851, says, as regards the period of their introduction:—
“About seventeen years ago your then surveyor (Mr. Kelsey) applied the first traps to sewer gullies, and from that date to the present the trapping of gullies has been adopted as a principle, and the city of London is still, I believe, the only metropolitan area in which the gullies are all trapped. The traps first constructed have since been (as all first inventions or adaptations ever have or will be) improved upon, and are rapidly being displaced by those of more improved construction.
“Now, of the incompatible conditions required of gully-traps, of the difficulty of obtaining such mechanical appliances so effective and perfect as can theoretically be devised, but yet of the extreme desirability of obtaining them as perfect as modern science could produce, your honourable court has, at least, for as long as I have had the honour of holding office under you, been fully alive to; no prejudice has opposed impediment to the introduction of novelties; your court has been always open to inventors, and, at the present time, there are sixteen different traps or modes of trapping gullies under trial within your jurisdiction.
“Nor has the provision of the means of excluding effluvium from the atmosphere been your only care; but the cleanliness of the sewers, and the prevention of accumulation of decomposing refuse, both by regulated cleansings, and by constructing the sewage upon the most improved principles, have also been your aim and that of your officers; and I do not hesitate to assert, that the offensiveness of the escape from the gullies has been of late years much diminished by the care bestowed upon the condition of the sewers.
“374 gullies have been retrapped in the City upon improved principles during the last year.”
The gully-traps are on the principle of self-acting valves, but it is stated in several reports, that these valves often remain permanently open, partly from the street refuse (especially if mixed with the débris from new or removed buildings) not being sufficiently liquified to pass through them, and partly from the hinges getting rusted, and so becoming fixed.