OUR PRESENT AND FUTURE WATER SUPPLIES
S. P. AXTELL, C. E., in an article on “Our Present and Future Water Supplies” recently published in the “Engineering Magazine,” enlarges on the difficulties encountered in procuring a supply of wholesome water, owing chiefly to the “characteristics of water as a scavenger and purifier of all decaying and putrescent matter by absorption, and holding in solution the active and death-dealing substances formed and given off in all the different stages of decomposition, and its affinity for all impurities.”
He regards all surface water as ” more or less contaminated and liable at anv time to become dangerously so.” owing to its having acted as a flushing and purifying medium-—this applying equally to ground water passing through a foul soil.
Filtration, of course, is a remedy; but on a large scale it is impracticable. Ilow could New York city filter and purify about 200,000,000 gallons a day? This, however, is not absolutely necessary, as pure water is not required for putting out fires or for flushing and mechanical purposes. Filtration, however, can be applied to about two gallons per capita daily of water for drinking and culinary purposes, in which case .j.ooo.ooo gallons daily would suffice for the wants of New York city. In the case of New York, therefore, Mr. Axtell would (t) use the present system for the main supply; (2)construct a new and pure water system distinct from the main plant; the miles of pij e at least equaling those of the main plant;
” but their capacity and that of the pumping plant and reservoirs being small and the system not requiring fire hydrants or many expensive special castings, the cost of construction would lie comparatively light. This plant can be built either upon the reservoir direct pumping or gravity system.
The first duty would be to secure the purest water supply possible—front a ground or spring source, and only after the water has been thoroughly analysed for impurities to lie removed by chemical or electric action, the purification to lie completed with a deep and thorough filtration.
” If the plant is to be built upon the elevated reservoir plan, the water thus purified should lie discharged from the filters into a clean, covered well, at the small pumping station, and from there pumped up into a series of small connected reservoirs. constructed of such shapes and dimensions as would render it entirely practical to erect permanent buildings over the same, to protect the water from the scorching rays of a midsummer stiu,as well as from dust and all pollutions which open reservoirs receive from animal and vegetable matter. Proper help should be employed to keep these reservoirs and buildings as clean and pure as an old fashioned spring-house,
Mr. Axtell recommends also that there be built in connection with these reservoirs, etc., a small refrigerating plant,
” and so much of the pure water lie frozen or refrigerated as may be necessary to keep the water in storage in a cool and palatable condition. The distributing and service pipes that conduct this water through the city to the consumer are usually placed at a sufficient depth in the ground to prevent any changes in tenqierature from materially affecting them, and, if the little service pipes, upon entering the building, were covered with some non conductive material, it would keep the water cool in the summer, and prevent freezing and bursting of pipes in the winter. If the system used is to be direct pumping, all constructions of the plant and all operations connected therewith would lie the same, with the exception that the reservoirs would then tie built in connection, and on a level with the pumping station, and the water would lie delivered from the engines directly to the consumer in the same pure and palatable condition. As the city will receive a good revenue from this pure water system. it can afford to lie liberal in its construction and care ; therefore, to obtain the desired sanitary result, it is recommended that the city tap the pipes of this service at its own expense, and run the water into every building requiring the same. This being done as a sanitary measure, it is believed that no very formidable ordinances would lie required to cause it to be universally used.”
As the supply would lxlimited, meterage must tie resorted to to prevent waste or illegitimate use, the tariff to lie, say, $1 per 1,000 gallons—a price that would be cheerfully paid, inasmuch as there would be no need of ice, so far as drinking water was concerned.
The cost of such a plant would vary to some extent. The larger portion of the system might be constructed with 3 to 6-inch pipe with a t-4-inch meter. Mr. Axtell estimates “$15,000 per mile—a figure probably much too high. It is reported that Philadelphia is contemplating the expenditure of $t3.000,000 to obtain a belter water. Estimating that she has about 650 miles of water mains, and would need as much for a pure supply, the system, on this basis, would cos’ $9,750,(XX) -a sa”ing in the cost of construction of about $9,250,000; moreover, the water obtained would be much more pure and palatable thau any surface water. Should she, however, adopt the dual supply, and charge for the pure watet, as she would be compelled to do to protect it from illegal use and waste, she would get from this source an annual income of over $750,000; and the amount would be cheerfully paid by the consumers, as they would get more than value received in the quality of the water.”
Mr. Axtell strongly urges on New York to make use of the dual supply system, and, should the Croton watershed become contaminated (“as it already is”) its water can still put out fires and an intake pipe could be run up the I I udson river above tide-water.through which all the water needed could be pumped. Brooklyn could do the same, if her ponds and sands on l ong Island failed her. A dual supply would cost Cincinnati, with her 250 miles of pipe, about $3,750,000—a saving of about $2,000,000 on the amount she proposes to expend on obtaining a pure supply. So in the case of Boston, Jersey City, Washington, Newark, Pittsburgh, etc.
The adoption of this plan would, of course, make a radical, but imperative change in the whole system, which has been in Mr. A.-;toll’s eyes radically vicious for many decades, owing ehiefly to the political methods that rule in every municipality and prevent the employment of expert hydraulic engineers, instead of mere civil engineers, each one of whom is supposed to be an expert in every branch of the engineering profession.
“The hydraulic engineer (Mr. Axtell claims) should be a man educated in his profession, capable of constructing an efficient fire protection system, which, by the way, is seldom found in our cities. How often do we hear of millions of dollars being lost for want of a proper water supply! There was enough water in the reservoirs, but, from small pipe or defective construction, it could not be obtained when wanted. ‘Hie hydraulic engineer should understand thoroughly the conditions and affinities of water, and especially should know what kind of water will benefit the human constitution.”
Political parties, of course, must be and are “commendable (Mr. Axtell thinks) on the ground that they produce discussion of the principles of government.” But their influence and workings should be confined to “questions of a purely national character” and should not be imported into the management of our municipal corporations to control them upon the principle that “to the victors belong the spoils.” In such a case “such politics becomes the bane of our social and municipal organization” and we find a lot of mere politicians influencing, often dictating “the appointment of officers whose duties are vitally important to the health, happiness, and safety of the whole people.”
Mr. Axtell holds that the system of water supply he has outlined will be entirely practical in its operation, as is “attended by the fact that every principle or method to be used in construction are such as have been in successful use for years. It is also known that Baris, the capital city of France, with over 2.500,000 inhabitants, has a dual supply water system. The only difference between the system I propose and theirs consists in the method of supply. Paris gives a prodigal domestic use of her pure spring water, whilst I restrict the pure supply to the smallest possible quantity.”