THE NEW YORK CITY WATER SUPPLY

THE NEW YORK CITY WATER SUPPLY

A new aqueduct for New York City, capable of carying more than 500,000,000 gallons daily, is under construction fort he entire distance from the Catskill Mountains to the New York City line. A storage reservoir (Ashokan) in the Catskills, having a capacity of 130,000,000,000 gallons, or 250 days’ supply for the whole city of Greater New York; another storage reservoir (Kensico), nearer the city, with a capacity of 40,000,000,009 gallons; and a distributing reservoir (Hillview), with a capacity of 900,000,000 gallons, are also under construction. Drawings and specifications for a deep tunnel, extending the Catskill aqueduce through the Bronx and Manhattan boroughs and into Brooklyn,a re ready for advertisement; and contracts for large pipe lines for carrying the new supply into theb oroughs of Queens, Brooklyn and Richmond, with a regualting reservoirin the latter, are partially prepared and will be let in time to receive the water from the tunnel,w hieh will be of slower construction. The total length of main aqueduct from Ashokan reservoir to Brooklyn is 110 miles, and the conduits through Queens, Brooklyn and Richmond comprise 10 miles of pipe line, generaly 66 inches in diameter, making a grand total of 126 miles. The cost of the whole scheme, including development of additional watershedsa nd filters, land, engineering and contingencies, is estimated at about $175,000,000. Nature has been against a vindication of the opinion that the city is indanger of a watre famine, int hat, with the exception of a few isolated years, she has sent unusually high rainfall since the necessity was first preached. All engineering computations as to the adequacy of an existing waters upply turn not on records of high rainfall and run-off. but on records of various series of dry years that have been experienced int he period for which records are available. Engineering structures are planned with a factor of safety. Most structures would actualy stand without destruction under at least twice the maximum load which it is expected they will ever be called upon to bear. The reckoning as to need for additional water supply provides no factor of safety. The writer computed in 1906 that if any one; of several series of dry years had occurred since 1868 should repeat themselves, the existing reservoirs would become absolutely dry in less than two years. In other words, New York City is dependento n a supply which is already taxed beyond the theoretical breaking-point. The first rlif from the new source will come in 1913 if no contractor whose work is at a limiting point fails marketedly in his guaranteed progress. Theextensions through the city, which arc necessary in order tod o more than guarantee the continuation of the present supply, cannot be completed until the middle of 1915 if started at once and prosecuted without unusual delays.

Ashokan Reservoir.—Now being built under contracts amounting to nearly $14,000,000. Capacity 130,000,000,000 gallons; elevation of water, 590 feet above tide; elevation of tops of dams. 610 feet above tide; length of reservoir, 12 miles; maximum width of reservoir, 3 miles; maximum depth of reservoir, 190 feet. The most important structure of the reservoir is Olive Bridge dam, the length of which is about 4.800 feet, including 1,000 feet all masonry and 3,800 feet earth with masonry core wall. The maximum height of the masonry dam from bed-rock to top is 220 feet, not including a cutoff wall about 20 feet wide, which extends about 40 feet deeper. The comparatively liberal dimensions of Olive Bridge dam are due to assumption of an ice-pressure of 47,000 pounds per linear foot of dam and upward waterpressure on two-thirds the area of horizontal planes, and varying from 0 at the toe to full bead at the heel of the dam. In addition to the Olive Bridge dam, dikes of an aggregate length of about 4 1-2 miles are required to complete the outer shore line. Ashokan reservoir is connected by an aqueduct passing under the Hudson river and 77 miles in length, with Kensico reservoir, which is 30 miles trom city hall. This reservoir, which is now being built under contracts aggregating nearly $8,500,000, has a capacity of 40,000,000,000 gallons, of which about 28,333,000,000 gallons can be run without pumping and at full or nearly full rate into the aqueduct southerly. Elevation of water, 355 feet above tide; maximum depth, 155 feet; elevation of top of dam, 370 feet above tide; maximum depth, 155 feet; elevation of top dam, 370 feet above tide; maximum height of dam. 20 feet, maximum width of dam, 230 feet. Kensico reservoir is so large as materially to simplify the problem of cleaning and repairing the aqueduct north and give security; against interruption of supply from any but the most serious and practically unheard-of accident. The. main feature of the reservoir is the Kensico dam, 1,830 feet long, and estimated to be 290 feet high at its maximum, not including cut-off wall.

Hillview Reservoir.—From Kensico reservoir there are 15 miles of aqueduct to Hillview reservoir, which is not far from the north boundary of the city. Its function will be to equalize the differences between the use of the water in the city as it varies from hour to hour and the steady flow in the great aqueduct, and to furnish large quantities of water upon immediate demand, as in a great conflagration. It will hold 900,000,000 gallons. The contract was let for $3,270,000. it is divided into two parts and a by-pass aqueduct is formed by a 12-foot circular void in the concrete division wall. The embankments are very wde, as a result of the large quantity of excavation required on that hilltop site to give the desired capacity with the minimum expenditure for construction and land, the latter being a large factor in that neighborhood. The great security afforded by these massive embankments is not inappropriate on account of the large population which is or will be housed around the site on the lower land.

Pressure Tunnels.—The Catskill aqueduct is unique in the number, length, and depth of the tunnels in rock which are to be used to carry high unbalanced internal water pressure. In the whole aqueduct north of Hillview there are seven (three adjoin and really form one long siphon) of these so-called pressure tunnels, aggregating about 17.4 miles, reached by shafts seldom less than 350 feet, and, in the case of the Hudson river crossing, 1,150 feet in depth. With the aqueduct in service, these tunnels carry unbalanced internal heads generally 200 feet or more, and in the case of the Hudson crossing, 410 feet.

The pressure tunnels arc placed at such an elevation, determined by frequent core borings, that sound rock to a depth of at least 150 feet will exist above them.

From Hillview reservoir to Brooklyn, also for a short spur in Brooklyn, 18.1 miles in all, the city aqueduct is a pressure tunnel, stepping down in size, 15, 14, 13, 12 and 11 feet in diameter. The tunnel is reached by twenty-five shafts generally between 180 and 300 feet deep but over 400 feet at the Harlem river and two buried gorge just southerly and over 700 feet at the buried gorge in Manhattan, near the East river.

The risers and appurtenances for connecting the tunnels with ihe distribution mains arc shown, in part, in the accompanying section. The concrete plug closing a shaft is to begin at least too feet down in sound rock. In this plug is embodied one or two steel pipe risers and these are lined with concrete about 5 inches thick. At the lower end of each riser is a valve consisting of a bronze scat casting and a bronze pear-shaped plug which is raised or lowered by lever operated by a rod running from the “dry” side of the valve to the surface.

*From a Paper to tile Engineers’ Club of Philadelphia.

The New York City Water Supply.

The New York City Water Supply.

THE precarious condition of the water supply of New York city has inspired the officials in charge to take more than usual precautions to prevent the waste of water. The methods adopted to effect this object will be watched with interest. The lowest altitudes above tide water where the greatest head exists should first receive the attention of inspectors. The next thing in order is the numerous bar-rooms and private stables. The waste of water from these sources of consumption is enormous.

The industrial consumers of water are, in most cases, metered, and it will not be worth while to spend any time upon them in the matter of inspection. The ground floor of premises will be found to furnish greater evidences of waste than the upper floors, the pressure being the greatest at the lowest altitudes. Water takers will take advantage of night pressure to fill their bath tubs and wash tubs, which they cannot get during the day. Inspection must be continued during the winter months.

It will be found as cold weather approaches the consumption will increase, by reason of water consumers permitting water to run to waste to prevent water in pipes freezing in exposed situations.

Out of all this present trouble and tribulation may come good, in that better discipline may obtain in the distribution of water. It is admitted that fully one-third of the water is wasted. It is the strongest kind of an argument in favor of the meter system not to curtail a legitimate use of water, but to stop criminal waste.

As a water waste preventer the water meter is the most complete apparatus of the kind known. It simply stops waste for all time. An army of inspectors cannot do it as effectively. As soon as the prospects of a water famine are remote discipline will be relaxed in the matter of inspection, and again waste will obtain and will continue until the day comes when public sentiment will demand a permanent restriction as a measure of public safety.

The prodigality of water consumption is a crime against the municipality, and why it should be permitted in face of the present experience is utterly incomprehensible to the water-works engineer of any experience.

Costly public works in the form of storage reservoirs and aqueducts are desirable and valuable to promote the efficiency of an abundant water supply and maintain it. It, however, cannot be denied that the vital question of prodigal distribution has been suffered to impair the main structure by reason of the enormous waste of the commonest of fluids when abundant, and which gold cannot buy when scarce.

Speaking from a standpoint of critical observation, one might say that the people of New York are suffering from errors either of commission or omission. It has occurred to us that the time is ripe for a serious consideration of the question of adequate fire protection.

If the present state of affairs continues to exist heroic treatment regarding adequate fire protection will be demanded. If it be impossible to obtain further supplies of Croton to even meet the reasonable expectation of seeing water flow from an open fire hydrant in sufficient quantity to supply a fire engine, the sooner this serious defect is remedied the better for all concerned. New York city has assuredly spent a vast sum of money to lead the water into the city. The vital question is now more water, enough to place us where we belong— at the head of the list.

THE heavy storm of Tuesday somewhat relieved the scarcity of the water supply of New York city, but by no means ended the trouble. As we write it is reported that the daily supply to the city has been limited by Commissioner Gilroy to between 80,000,000 and 90,000,000 gallons, while the use of water has been prohibited in public and club baths and for the washing of vehicles, etc., by means of hose. In residences and business houses in many parts of the city the scantiness of the supply is also causing great inconvenience.

NEW ORLEANS evidently needs to revise her building laws. The Grand Jury, which has been investigating the cause of the falling of the walls of a building on Royal street, by which three men were injured, has found that the building had been condemned and the walls ordered torn down several months before, but that the owner had, nevertheless, in rebuilding let the insecure walls remain. The Grand Jury calls attention to the deficiency of the building laws, and suggests that they shall be so amended that the city shall have official supervision over buildings, with power to enforce all orders. With the Park place disaster in mind, far be it from us to cast a stone at New Orleans ; but, if the safety of the citizens is not to be left at the mercy of mean and unscrupulous propertyowners and builders, the suggestions of the report should be carried out without delay.

THE exhibition of means and appliances for the prevention and extinction of fire which is to be held at St. Petersburg is one which will attract the particular attention of American inventors and manufacturers of fire department apparatus and supplies. There will be various sections devoted to means for the prevention of fires, devices for announcing their outbreak, apparatus and chemical compositions for their extinguishment, appliances for saving life and aiding the injured, the organization of the fire service, fire statistics and literature—in fact, every branch of the subject in question. Medals and awards and money prizes will be given for the most useful inventions. There should, and doubtless will be, a full and interesting exhibit from the United States, which may be counted upon to produce some good results. There are a number of devices of American origin which, without question, need only to have their practical working exhibited to unprejudiced foreign fire department officials to insure a recognition of their usefulness.

THE urgent need of enlarging the over-taxed fire department of the city of Cleveland was asserted one day last week to the reporter of a local paper by Director Black and Chief Engineer Dickinson, and a disastrous blaze among business property was predicted as a probable consequence of neglect to provide the required reinforcements. Just five days later, a fire starting in the heart of the downtown business centre, destoyed a big printing house and damaged four other buildings, causing a loss of about $200,000 in property, the death of one fireman and the injury of two others, and only by the very hardest work upon the part of the department was kept from doing still more damage. Just how much of this loss would have been averted had the department possessed the additional fire apparatus judged necessary by the chief engineer, cannot well be estimated, but it is odds that it would have been considerably more than the cost of the apparatus. What the result would have been had another large fire gained headway elsewhere while nearly all the apparatus was engaged at the first blaze, can also be well imagined.

WHILE upon this side of the water we are discussing the question of how best to protect our modern large buildings from fire, it is interesting to note what our British cousins have been doing in the same direction. The large building in which are located the offices of The Glasgow Herald is popularly supposed to bear a charmed life. Three times within the past few years adjoining buildings have been destroyed, and at one time the offices were practically surrounded by burning structures but only a part of the roof was destroyed. Despite this good fortune, however, every precaution against fire has been taken within the building, the various departments being fully equipped with automatic sprinklers, to supply which there is a large tank and a water tower, both connected with the mains. In addition to this, however, and to guard against the danger from exposure to fire from without, a system of perforated iron pipes finished with zinc to prevent rusting, have been run along the ridge of the roof and above all of the windows. By means of these pipes it is intended, in case of need, to keep water flowing over the roof and windows to guard them against flames from without. The water would be supplied from the tower and tank, and a pump used to force it to the highest parts of the building. The pipes are, as before noted, to be kept dry, so as to prevent freezing. The scheme is certainly simple, and appears as if it might prove very effective under many circumtances.