Art. XXII.—Draining of Towns: Results of having Outfall Drains within Sydney Harbour.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 9, 1876, Page 260

Art. XXII.—Draining of Towns: Results of having Outfall Drains within Sydney Harbour. Communicated by W. R. E. Brown, Registrar-General. [Read before the Wellington Philosophical Society, December 7th, 1876.] When the subject of the drainage of towns was lately brought before this Society, the discussion assumed somewhat of a local aspect. In view of the conflicting theories held and of a possible large expenditure on drainage works, I requested Mr. Von Dadelszen, of my department, who was about to visit Sydney, to endeavour to obtain some information as to the practical results of allowing the harbour to be a receptacle for the drainage of the city; more especially with regard to the effect on the health of the inhabitants. The latter data are not obtainable on account of reasons given, but their absence is, however, far from being evidence that the health of the population is not, in parts of the town, seriously affected by the cause stated. On the contrary, the evidence given before a Board constituted to inquire into the subject of “the sewerage of the city, and on the best means of protecting the inhabitants thereof,” points unmistakeably in the other direction. From the length of the letter, addressed to me by Mr. Von. Dadelszen as the result of his enquiries, an abstract only can be given, and I cannot do more than refer any gentleman who may desire fuller particulars, to this and the reports of the Board, and the evidence taken before it. The evidence taken before the Board contains much that is well worthy of attention. I trust that the experience gained may not be thrown away upon us, but that the evils, proved to exist, may serve as beacons to prevent us wasting health and material resources by adopting systems that have been found insufficient or injurious:— “According to request, while on my late visit to Sydney, I called on

Mr. Ward, the Registrar-General, and inquired if any information as to the influences of the drainage discharges was shown by the health statistics. He informed me that owing to the situation of the wards from which the mortality tables are compiled, no comparison in the way enquired about could be established. “Mr. Ward, however, introduced me to Professor Pell, of the Sydney University, who is chairman of a Board appointed in 1875 to enquire into and report upon the best means of disposing of the sewage of the city of Sydney and its suburbs, as well as of protecting the health of the inhabitants thereof; and such information as I have obtained from the reports of the Board now before me I will endeavour to review under the following different principal heads. “Effects of Discharge of Sewage into Harbour. “The evils occasioned are two. “1. The contamination of the shores and harbour. “2. The silting up of the harbour. “The substances it is desired to dispose of otherwise are as follows:— (1.) The light contaminating matters, partly in suspension and partly in solution, which create the nuisance. “(2.) The fine sand, comminuted clay, and other purely divided earthy matters, which are at all times brought down by the sewage water, and in large quantities during heavy rains. This matter is carried over every part of the harbour, and even far out into the ocean, and slowly settles to the bottom. “(3.) The coarser sand brought down in times of flood, a part of which is deposited at the bottoms of the sewers, generally near their mouths, and a portion at or about the outfalls, forming in some cases sand-banks which become polluted by the offensive organic matter. “The committee reports show how great the evil is of discharging it either on a foreshore or spreading it abroad on the surface of the water. “An extract from the report of the committee for the investigation of crowded areas and dwellings, shews, that the committee found the odour at the bottom of Liverpool street at midnight was so offensive, at low tide, that they could not have credited it, without personal experience of it, and that no description yet published equalled the foul reality. “Mr. Moriarty, Engineer-in-chief for Harbours and Rivers, in his evidence before the Board, states that the nuisance from the sewage floating on the surface of the salt water is frightful, and that offensive mud-banks are formed, and as a matter of fact we hear that the outlets of the sewers are invariably offensive, and that the reason, why the harbours and rivers become polluted with animal and organic matter, is that this matter is

discharged with a lot of sand and mineral matter, which entangles it and causes it to sink to the bottom and putrify. That there is no sewage matter which of itself would not float, and could not form a deposit were it not entangled and kept down by some heavier substance. The main sewers collect both the house sewage and also the street washings, and when mixed together form putrid mud at the outlets, which is very offensive. “In a report, attached, ‘of the Committee appointed by the Sydney City and Suburban Sewage and Health Board, 16th July, 1875, to examine and report upon the outlets, of the city sewers, discharging into the Harbour,» it is stated, that silt-pits are used to intercept heavy particles before discharge at the outlet; that one constructed at the Market Wharf outfall has stopped the silting up of the outlet. It contains, when full, 100 tons, and fills up about every six months. The area drained by it being about eleven and three-quarter acres. “The evidence of Dr. Alleyne, taken after the reading of the above-mentioned report, shows clearly how offensive is the matter discharged in spite of these silt pits. At Fort Macquarrie the rocky bottom is covered with a film some inches thick, which has rendered reclaimation necessary. “A letter from Captain Nares is appended, dated 19th November, 1874, giving a bad account of the state of the anchorage in Farm Cove, and stating that the moorings there have already had to be moved in consequence of the unhealthiness of the previous position, due to the discharge from the sewers. “I myself found on arrival at Sydney, that the smell was so abominable as to render it impossible to remain in the berth-room of the Newcastle steamer, while the port-hole was open; and I was forced to leave the vessel's cabin and walk about in the town until the hotels opened. “Method by which the Pollution of the Shores can be lessened. “Iron pipes are to be laid down from the mouths of certain sewers to convey the ordinary dry weather flow into deeper water, at a distance of about 120 feet in one case from the present outlet. The description by Mr. Moriarty of his plan for this work is appended, in which he condemns the sewage being allowed to flow into the Harbour at all. “Decision of the Board in Sydney to Divert the Sewage from the Harbour. “The sewage is to be discharged for the most part by gravitation through a tunnel to the ocean, or by tunnel, pipes, and conduits, to some tract of land suitable for sewage farming. “In addition to the subject you directed my attention to more particularly, I append remarks on the pollution of the water supply, owing to water-closets being directly connected with the mains. This is a great source of sickness. An investigation of this subject was instituted, and

Dr. MacLawrie gave strong evidence on the evils due to this cause, *Dr. MacLawrie, in his evidence attached to First Progress Report, stated that, in the Harbour of Wellington, N.Z., the crew of H.M.S. “Challenger,” having had occasion to use the water from a former town supply, now superseded, an outbreak of diarrhœa occurred, and continued for about three weeks, and it ceased on the supply being stopped. The water was found to have been contaminated with fœcal matter from cesspits in the town during the heavy rains. The water had a disagreeable smell, and the suspended particles gave it a milky consistency. and the result of it was a recommendation that an Act be passed (which is now law,) requiring that every water-closet should be connected with mains only with the intervention of a cistern, approved by the City Engineer as being of such construction as to prevent the pollution of the water. “Remarks are also appended upon cesspits, which are still necessary in some parts of Sydney. It has been recommended that, to lessen the evil effects of cesspits, full powers should be given to the local authorities to regulate the construction of cesspits as to their size and situation; and to insist on their being made water-tight; and also that the duty of cleansing them be transferred to the town authorities, and owners of houses relieved of all responsibility in the matter, except as regards payment for the work done on their behalf; and 300 acres be authorized by an Act to serve for the deposit of the night soil. “The earth-closet system is discussed in the Fifth Report of a Committee of the British Association on the treatment and utilization of sewage, in which this system is condemned. And in the Third Progress Report of the Sydney Board it is considered practically impossible to secure proper management, and a supply of suitable earth; that they would not diminish the contamination of the sewers; and that the manure is of little value. “Crowded Dwellings and Areas. “A portion of the work devolving upon the Board in Sydney was the investigation of crowded areas and dwellings, and the results of the examination show the effect of allowing land to be divided according to the will of the proprietor, uncontrolled by thorough legislation for the protection of the health of a town population. “I have endeavoured in the above, to compress, into a short space, from the reports under my notice, an account of the principal matters being dealt with in Sydney. There are no less than eleven progress reports of the Sydney Board, all supported by minute and carefully-taken evidence; from them much more might be gathered if necessary. The contents are only briefly alluded to in this letter. The work of the Board is most thorough in its character, and done at a very great expense to the Government.”

Reports and Acts referred to in Mr. Brown's Paper. An Act for preventing the pollution of the water supplied to the city of Sydney and its suburbs. Assented to, 22nd July, 1875. Report to the Sewage and Health Committees upon the Sydney city and suburban water supply, by A. Liversidge, F.C.S., F.G.S., Prof. of Geology and Mineralogy, Sydney University. Printed, 24th July, 1875. Report from City and Suburban Sewage and Health Board, respecting disposal of night soil in Melbourne. Printed 20th July, 1875. Report of the Committee appointed by the Sydney City and Suburban Sewage and Health Board, on 11th July, 1875, to examine and report upon the outlets of the city sewers discharging into the harbour. Prof. A. Alleyne, chairman. Adopted, 15th September, 1875. An Act for preventing certain nuisances in the city of Sydney and other municipalities, 11th August, 1875. Third report to the Sydney City and Suburban Sewage and Health Boards upon the quality of the Sydney city and suburban water supply, by A. Leversidge. Dated 11th May, 1876. Progress reports of the Sydney City and Suburban Sewage and Health Board, appointed 12th April, 1875, to enquire into and report as to the best means of disposing of the sewage of the city of Sydney and its suburbs, as well as protecting the health of the inhabitants. First Report Printed, 6th May, 1875. Second " " 25th June, " Third " " 19th July, " Fourth " Adopted, 25th Aug., " Fifth " Printed, 16th Nov., " Sixth " " 23rd Nov. " Seventh " " 3rd March, 1876. Eighth " " " " Ninth " " 26th May, " Tenth " " 4th July " Eleventh " " 16th Aug., "