The Municipal and Sanitary Engineer's Handbook

by H. Percy Boulnois

The last question that arises on the subject of scavenging before we consider the disposal of snow, is whether the onus of cleansing private courts and alleys which are not repairable by the urban authority should be borne by them or not.

The great difficulty attached to this duty arises from the fact that these private courts and alleys are generally very badly paved, if paved at all, full of pits, where pools of stagnant mud and water collect, and even in the best cases, the interstices between the pebbles, or other paving, are filled with filth arising in great measure from the dirty habits of the people, and this filth it is found exceedingly difficult to dislodge. The remedy for this is to compel the owners of the abutting properties to have the courts and alleys properly paved with asphalte, or other equally impervious material, after which it would be easy for the urban authority to cause them to be swept at least once a day, and flushed with water in the hot weather once a week, but in order to compel the owners to execute this very desirable work it would be necessary to put the complicated machinery of section 150 of the Public Health Act 1875 in force, and the expense to the landlords would be in many cases very disproportionate to the value of their property.

Out of the ninety towns to which reference has before been made, the authorities of only nineteen of them cleanse the private courts and alleys in their jurisdiction, although for the sake of sanitation it is very desirable that such work should be so undertaken by them.

In most towns it is necessary to cleanse its principal streets at least once a day, and this appears to be the practice of nearly all the ninety towns I have referred to; only seven of them, however, appear to have this operation repeated more frequently; in several towns, the horse droppings, &c., are removed at once, under what is called the “orderly” system, and this is especially necessary in streets that are paved with such materials as wood paving, asphalte, or granite setts. The suburban streets of a town need only be cleansed once or twice a week, except in special cases of extremes of mud or snow, and I will now proceed to discuss the questions involved by a heavy fall of the latter.

Experiments have shown that a cubic yard of fresh fallen snow may weigh as much as 814 pounds or as little as 71 pounds. Assuming that a cubic foot will weigh 16·38 pounds, I estimate that for a fall of 3 inches of snow upon a street 36 feet in width, 20 tons, representing a bulk of about 100 cubic yards, would have to be removed for every 100 yards of length of street if it was thought necessary to clear it away.

Assuming that there are 30 miles of street in a town from which the snow must be removed; 21,144 loads must be carted somewhere, at a cost of at least 1,500l., assuming that each cart could make ten trips a day, and even then it would take 352 carts a whole week to effect it.

It may be contended that I have taken an extreme case, and that, of course, the snow does not lie for very long upon the ground in the condition in which it fell, and that hourly it is reducing in bulk and weight by being ground up by the traffic, and finding its way in the form of water into the sewers. This may be so, but at the same time it must not be forgotten that the bulk is also being constantly increased by that which is shovelled off the house tops[168] and brought out from private premises adjoining the streets.

Upon this point Mr. Hayward, the Engineer to the Commissioners of Sewers of the City of London, says[169]:—

“Snow readily compresses under the traffic, and when removed in carts and shot down elsewhere it may be assumed that on an average four cubic yards of snow measured as it has fallen is equal to one cubic yard when placed on the apparatus.” This computation, however, does not make any allowance for the snow thrown from off the roofs, &c., and it of course greatly consolidates whilst travelling in the cart.

Fortunately for a town surveyor in this country, exceptionally heavy falls of snow are not very frequent, but when they do happen great pressure is put upon his department to cope with it, and one of the greatest difficulties he has to contend against is the disposal of the snow after it has been placed in the cart.