Sessional_Paper_1902 — Page 559

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the fact that the opening, from the gulley to the sewer, is greatly restricted. The state of the weather may have some influence in this matter, for sewer air does not always ascend.

The original idea was to provide two traps, in the side-channels of the street, one (in case of junctions, two) was to have been small, and with a closely-barred grating, destined to take any 'dry-weather flow to the street-sewer.

The second, placed lower down, was to have a large and open-barred grating, was to have been connected to the storm-water Drain, and was intended to take flood water, during heavy rain.

This arrangement has been found to present the difficulty that when the side- channels are washed down an undue amount of road detritus, vegetable matter and the like, is swept into the sewers through the Street Sewer gulley. This inconvenience has been greatly aggravated by the improper use of the gulley-gratings, that have been provided. Large open-barred gratings with sloping bars, were to have been provided solely for use in the inlets to storm-water drains. They were made large and open-barred, to admit rain-water freely. The sewer-gratings were to have been small and close-barred, so as to admit as little surface water as possible to the sewers. But I find that the Drain-gratings have often been used as Sewer-gratings.

Much dry-refuse, also, is but too often thrown into the gulleys, both of the Street Sewers and of the Drains. To remedy this evil, the Honourable the Director of Public Works has devised a special form of trapped gulley, common to both sewer and drain, trapping both. It is provided with a locked cover, so that it is inaccessible to unauthorised persons. One of these is in use at the foot of Icehouse Lane. Some minor modifications may be desirable. I am, however, of opinion that this arrangement might be tried, on a larger scale, when doubtless, some thoroughly satisfactory type will be evolved. The radical remedy for this trouble will, however, be found in an improvement of the scavenging system, a question to which I will return later on,

sewer gulleys

72. I am of opinion that more trapped sewer-gulleys are desirable, in some parts More of the town. The side-channels of the streets in many cases, are very nearly level, trapped Now the side-channels receive the effluent from down-pipes from verandahs, required. the washings of which are practically sewage. Indeed, I believe that chamber-slops are, in some cases, poured down the rain-water pipes. The effluent from the down-pipes has often a long distance to travel, before reaching a gulley, and owing to the flatness of side-channel and its small fall, stagnation results. In such cases, it would be well to provide additional gulleys, near to the foot of the down-pipe. This, moreover, would have the effect of diminishing at least, the necessity for washing the side-channels, an operation which tends to introduce into the sewer road-detritus, and other solids.

control and

73. At the present moment, street scavenging and the cleansing of gulleys is Duality of directed by the Sanitary Board. House sewers are also constructed and supervised division of by the Board. The management of the Sewers, below ground, is directed by the authority. Public Works Department. Consequently, there is a division of authority. If the street-sewers become choked, then the Sewerage Authority attributes the blame to

scavengers, and so forth.

the

entrusted to

74. I therefore recommend that the maintenance of the Street Sewers be cleansing of entrusted to that department of the Sanitary Board, which has the control of sewers to be scavenging, namely, the Medical Officer of Health. I may here state that with the Sanitary sewers, drains including nullahs, open or covered, should be included.

By the word "maintenance" I mean the scavenging of the Sewers, namely, flushing, removal of obstructions, and all operations which do not involve breaking- up the surface of the ground. Extensions alterations, and new works generally, should, as heretofore, be executed by the Director of Public Works, and when complete, handed over by the Sanitary Board.

Board.