NEW YORK’S WATER SUPPLY

Evening Star, Issue 18808, 5 December 1924, Page 12

NEW YORK’S WATER SUPPLY

HOW PURITY IS ENSURED. Where, as in the case of New York, populous communities are dependent for their daily and indispensable supply of water on what are known as surface sources—i.e., lakes, ponds, rivers, streams, etc.—which arc after all only Nature's means of collecting, storing, and distributing the water raised, in the form of vapor, from 'the earth to be returned in the shape of rain, hail, snow, hoar frost, dew, etc., the greatest care has to bo taken to protect the water thus obtainable from contamination, purity being an even more essential quality than potability. I’rom the above remarks (says (lie ‘Australian Mining Standard ’), it will bo evident that to furnish the immense volume of water required by such a city as New York, with its population, according to the latest census of 1910, for the Greater City, totalling 5,620,048. a wide area must he "drawn on"; as a fact, the total area, of the watersheds from which Greater New York derives its supply is 632 square miles.

As niny readily be supposed, this widespread territory includes many settlements, villages, towns, even cities of considerable magnitude, to say nothing of innumerable farms, residence sections, industrial plants, etc., being located within its limits, and one of the first and most important lines of precaution is to guard against any contamination of the source oi water supply entering into the big city’s system, by the discharge into the water sources of sewage, drainage, factory refuse, or any oilier objectionable matter. This is obviated by the vigilance of a special detail of the State constabulary, constantly patrolling the reservoirs, water courses, etc., with a watchful eye for any proceeding on the part of residents that might'.possibly result in the introduction of harmful elements into the water collected for the big city’s use, and of which the average daily consumption in 1922 was 7*16,700,000 gallons. How wo!! this duty is performed mav be gathered from the fact that the number of deaths from typhoid fever in (ho Greater City, due in most instances to impure water (though impure milk and other foods may also be contributory causes), was, in 1922,. only 129. But reliance is not placed on watchful supervision alone as a means , of safeguarding the city’s water supply. In its transmission from the source to the consumer every means is adopted to protect its purity. The great aqueducts through which it' passes, one of which, the Sliandaken aqueduct, recently completed: at a cost of 12,000,000 dollars, will make a daily addition of 250,000,000 gallons to the city’s available supply j are' all steelcased and lined with concrete. This latest addition to the city's water resources includes in its route the largest tunnel in the world, necessary to bring the water under the Catskill Mountain;, a distance of 95,740 ft, -with a carrying capacity of 600,000,000 gallons in twenty-four hours. A further and most important step n maintaining the purity of the supply consifts in the taking of samples froni each source, at frequent intervals, which are

sent to New York. They tiro subject' to chemical, microscopical, and bacteria!• gical examination by experts. The water Unis collected is deli vena into immense reservoirs, of sufficient caps city to supply the city (or many week? in case of tho conduits being tcniporaril closed, owing to accident or for repairs Located conveniently near the eitv *' are at a sufficient altitude to effect distribution without pumping, im... also servo as settling basins, where the solid impurities the water may carry are deposited. But there by no moans constitute all the precautions taken to ensure the purity of tiro supply. Before the water enters tho tube on the last stage of its journey to the city, it passes through a chamber where a sufficient quantity of chlorine is added to destroy any germ life present, scientists having established tho fact (hat certain minute bacilli act as tho seeds of some of the worst of the zymotic diseases. To these minute organisms chlorine is deadly, and sufficient is admitted to ensure their extirpation, all of which is dif fused and disseminated long before the water reaches the consumer.

In its long journey through closed conduits the water has lost much of the air. without which it tastes fiat and insipid. Aerators, in connection with the principal reservoirs, supply the deficiency. They are great fountain basins, about 600 ft by 259 ft.

with about 1,500 nozzles, through which the water is ejected. In its ascent and descent in the form of spray, it takes up the desired proportion of air and is, at the same time, freed from undesirable gases and odors. With all the precautions above described the purity of the city’s water supply, which is undoubtedly a factor of importance in its low death rate, is not remarkable, nor are its citizens likely to begrudge the 185.000.000 dollars expended in perfecting the system, nor the large sums expended annually in maintaining its efficiency, both as a means of furnishing a necessity whore health and cleanliness are concerned and at the same time 1

helpful protection from fire. For the tatter purpose, however, tho inexhaustible supply in the rivers and harbor of New York can bo drawn on.