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The World's Greatest Aqueduct
Water From The Catskill Mountains To The City
Of New York
By Alfred Douglas Flinn, Engineer, Headquarters
Department of the Board Of Water Supply of the City of New York
from
Century Magazine, 1909
The Catskill Mountain water system being
constructed for New York City is one of the most notable engineering
enterprises ever undertaken. Ranking with the interoceanic canals at
Suez and Panama, the Assuan irrigation works in Egypt, and the
projects which are converting Western America's arid wastes into
fruitful fields, the Catskill aqueduct, with its tributary
reservoirs, probably surpasses any one of them in the variety of
problems to be solved. Although undertaken by a municipality, these
works in magnitude and cost compare with national enterprises.
Imperial Rome's longest aqueduct was
fifty-seven miles in length; the Catskill aqueduct will be ninety-two
miles long. Rome, with hordes of laborers from conquered domains,
carried its aqueducts at the hydraulic gradient across valleys on
imposing masonry arches. Modern explosives and rock-drills enable New
York to tunnel in solid rock beneath valleys and rivers, avoiding
masonry, which is now expensive, and which is likely to suffer in New
York's severer climate.
-THE EDITOR.
CATSKILL MOUNTAIN water, gathered from brooks
that have been fed by melting snows and copious rains, and have
tumbled over rocky slopes into the streams of the mountain valleys,
will in a few years be served to the inhabitants of New York City.
The project ranks as the greatest municipal water-supply enterprise
ever undertaken, and as an engineering work is probably second only
to the Panama Canal. The need of the water is much greater than is
realized by a majority of the citizens or by the guardians of their interests.
Nothing can so quickly and completely
disorganize the complex activities of a modern community as a
shortage of suitable water; no single agency can so rapidly spread
disease and death as a polluted water-supply. For several years New
York has been using more water than its sources of supply can safely
be depended upon to furnish in a series of dry years, such as have
occurred within the memory of men who have scarcely reached middle
age. Continuing years of abundant rainfall have masked the danger to
which engineers have repeatedly called attention.
In 1905, as the result of a movement promoted
by civic bodies in the days of Mayor Van Wyck and Mayor Low, a bill
was introduced into the legislature, on the initiative of Mayor
McClellan, which, becoming a law, enabled the city to start new
systems of water-supply that, with the already existing permanent
works, should ultimately give New-York the best and largest water-supply
ever known.
As thousands of water-wise Americans know, New
York City ("old New York") has used Croton River water for
more than two generations. Similarly from the Ridgewood system of
wells, streams, and reservoirs, Brooklyn has drawn its supply, often
scanty. Approximately five hundred million gallons of water are
consumed by the metropolis every day, a stream which would flow
hip-deep between the buildings in Fifth Avenue's fashionable shopping
district at a comfortable walking pace. For every man, woman, and
child this allows a daily average of 125 gallons. Or, to put it still
another way, for all domestic, manufacturing, and public purposes New
York uses every day water which weighs about eight times as much as
its population.
Compared with the 130, 140, 200, 220, and 320
gallons used every day for every person in several large American
cities, New York's allowance is moderate, especially when one recalls
the character of business and the methods of living which prevail in
the metropolis. Liberal, even lavish, domestic use of water is not
waste. The very necessities of life demand that there should be a
maximum supply, in order to provide for the average-demand for the
individual. The word "waste" should be properly
interpreted. Its use in writing about water-supply has been
unfortunate, for it has been employed both technically and popularly
to characterize quite different conditions in the economy of water.
To let a dozen glassfuls flow from a faucet in order to get one cool
draft is not waste so long as this is the least expensive way to get
cool water. In a broad sense, to permit water to flow from the
faucets through cold winter nights is not waste so long as this is
the least expensive way to protect one's plumbing fixtures. To allow
even large volumes of water to spill over the lowest dam of a
watershed is in no sense waste when the city has already taken from
the stream all that it can use, or when the saving of occasional
discharges of this sort would cost more than to get the same quantity
of water, of equal or better quality, from another stream. Doubtless
some water is carelessly or wantonly wasted in New York City, but not
nearly so much as some persons assume. Waste should be discouraged
and curtailed, but waste of water can no more be wholly prevented
than the waste of energy and time. But if all the waste which it
would be reasonably practicable to stop ceased, New York would still
require more water-works to provide beyond peradventure for present
needs and future growth.
Croton River drains into New York's reservoirs
the water of 360 square miles of forest and farm, and can safely
furnish about 336,000,000 gallons daily. Two aqueducts, one
thirty-four miles long, built in 1842, and having a daily capacity of
80,000,000 gallons, and the other thirty-two miles long, built in
1891, and having a capacity Of 300,000,000 gallons, bring this water
to the city. To procure 500,000,000 gallons of Catskill Mountain
water daily, over 600 square miles of mountain and meadow will be
brought under tribute, several large reservoirs created, and an
aqueduct ninety-two miles long built, with many miles of conduits
within the city limits.
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View looking North from West Point Water
Battery of the Hudson between Storm King and Breakneck |
The extent of these existing and proposed works
is not readily to be comprehended even when reduced to the common
money measure. For the portion of the Catskill works needed to bring
into the city every day unfailingly 500 million gallons an
expenditure of $162,000,000 is estimated. But these disbursements
will be spread over many years, and the burden will not fall heavily,
except for possible temporary difficulties in raising ready money for
construction payments. Indeed, the cost of water for every person
will be on the average less than one cent per day. Furthermore, these
water-works, well managed, will not only pay interest on the
investment and cost of operation, but in a relatively few years will
pay the capital cost. It is reasonable to believe that the works will
be as permanent as those of Rome. |
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Because of its antiquity and impressive ruins,
the water-supply of ancient Rome is doubtless the most famous in the
world. In 97 A.D. the imperial city had no fewer than nine aqueducts,
with an aggregate length of 263 miles; but if the water that all
those aqueducts could carry (estimated at 84,000,000 gallons per day)
were put into New York's Catskill aqueduct, it would rise only to the
height of about three feet and three inches.
In the angle of the State west of the Hudson
and south of the Mohawk are hundreds of square miles of territory
partly forested, but in the main little cultivated and sparsely
populated. From time to time the large timber has been cut; the farms
have depreciated. From the hills tens of thousands of square feet of
bluestone have been quarried for sidewalks,but within twenty years
even this industry has been almost supplanted by the use of Portland
cement concrete. There remain the bracing air, the attractive
scenery, and the abundant rainfall; and thousands of holiday-seekers
flock thither. Their entertainment now constitutes the most
profitable business of the region, and will not be interfered with by
the project. The city, therefore, is not destroying large commercial
or agricultural industries, but is simply making the highest use of
one of the principal resources of the region, its water.
After repeated investigations, the most
thorough of which were those of the Burr-Hering-Freeman commission,
eminent engineers appointed by Mayor Low in 1902, several large
streams in the Catskills were selected for successive development as
needed. Esopus Creek, above the best dam site, has a drainage area of
257 square miles; Rondout Creek has a useful watershed of 131 square
miles; above the selected point of diversion, Schoharie Creek drains
228 square miles; and 142 square miles of the basin of Catskill Creek
can be utilized. Thus, with the addition of several minor streams, a
total water-gathering area of 885 square miles has been found, which,
it is conservatively estimated, will yield even in a series of dry
years about 770 million gallons daily. These waters are all of
exceptionally high quality, and, barring Catskill Creek, are
remarkably soft. In this respect even the latter suffers only by
comparison with the unusual softness of the others.
Although turbulent torrents of great volume
rush through the gorges of these mountain creeks in flood-time, in
late summer the streams could all be run through four-foot pipe, one
of the street mains of large city. But a great community does not use
water in any such irregular fashion, and nature must be regulated to
meet the necessities of man. The flow must be controlled, so that
flood excesses may supplement drought deficiencies. Great impounding,
or gathering, reservoirs are the means which engineers employ to this
end. In the Catskill scheme eight large impounding reservoirs are
contemplated, of which the first, to be constructed, and by far the
greatest, is the Ashokan reservoir on the Esopus. In the southeastern
corner of this mountain region geologic forces have provided a great
basin in which can be stored not only the waters of the Esopus, but
also part of the water of the other streams. Through one of the
ridges a tunnel aqueduct ten miles long will bring in the Schoharie
contribution, while the Catskill Creek water will flow through an
arched masonry conduit, to be built mostly in trench along the
eastern slopes of the mountains for thirty-two miles. From the
Ashokan reservoir the main aqueduct, called the Catskill aqueduct,
will convey the water to the northern boundary of New York City. Into
this aqueduct, about six miles below its starting-point, a branch
aqueduct will bring the water from Rondout Creek.
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Map of the Catskill Aqueduct System
Section of "Cut-And-Cover" Aqueduct
Grade Tunnel on Left, Pressure Tunnel on Right |
But what is an aqueduct? How large is this one?
If the curious inquirer will visit Peekskill, New Paltz, or High
Falls, where construction is in progress, he will come upon a great
trench, in some places thirty feet wide at the bottom, with steam
shovels, rock-crushers, concrete-mixers, and hundreds of men and
horses at work.
Here and there stretches of concave concrete
paving have been laid in the bottom of the trench. Elsewhere this
paving is being covered by a large concrete arch, thus forming a
great tube, or conduit, shaped something like a horseshoe, seventeen
feet high and seventeen and a half feet wide inside.
Over this concrete conduit, wherever it is not
wholly buried by the depth of the trench, an embankment of earth will
be built, except where the trench is mostly through rock, where the
bank will be made partly of the rock fragments. Through this aqueduct
a railroad coach could easily pass, with a man sitting on top, and
there would be room on each side for a man on horseback. In this
aqueduct water will flow at the maximum speed of four feet per
second, or two and three quarter miles an hour, a comfortable
promenading pace, or at the average daily quantity rate of 500
million gallons. This quantity of water, flowing at the velocity
mentioned, would make a stream about four feet deep in the ordinary
cross-town street of the Borough of Manhattan.
This is the cut-and-cover, or open-cut, type of
aqueduct, and is built along the hill slopes or across the flat lands
wherever the topography permits a trench to be dug at the proper
elevation. In this kind of aqueduct the water flows freely, as in a
brook, and not under pressure, as in a pipe under the street. Of the
cut-and-cover aqueduct there will be approximately fifty-four miles.
But the topography and geology of the Hudson
valley do not permit the Catskill aqueduct to follow a smooth grade.
To avoid long and expensive detours around hills, and to pass ranges
of mountains and hills which it would be impracticable to go around,
tunnels are being driven through them at the same elevations that the
cut-and-cover aqueduct would occupy if the topography were more
favorable. Since, however, tunneling is more costly than open-trench
work, the size of the aqueduct in these tunnels is less, the
dimensions inside being thirteen feet, four inches wide, and
seventeen feet high. In order to get the same quantity of water
through them, a more rapid flow is necessary and therefore the slope
is a little steeper.
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Of such tunnels, known as grade tunnels, there
will be twenty-three in all, aggregating thirteen and a half miles in
length, or approximately as long as Manhattan Island. Virtually the
whole length will be in solid rock, and, whether in rock or earth,
will be lined with concrete, so as to provide a smooth, clean surface
for the water and to prevent the falling of rock or earth from the
roof or sides.
In passing, it may be well to explain that the
concrete which will enter largely into the construction of the
aqueducts and is a mixture of Portland cement, crushed stone or
gravel, and water, very thoroughly combined in special machines. When
first made, such concrete is plastic or fluid, according to the
proportion of water, and can be formed or cast into any desired
shape; but in a few hours it sets, or hardens, and rapidly becomes
like stone, continually to increase in strength for months, and more
slowly for years. Portland cement, a heavy, gray powder, is
manufactured in many parts of the country, but that used in the
Catskill works will doubtless come mostly from the Lehigh Valley
district of Pennsylvania and from the vicinity of Catskill village,
New York. The suitability and availability of concrete greatly
facilitate and cheapen the construction of dams and aqueducts,
displacing more costly brick and stone masonry. Forms of construction
which would be impracticable with the latter are entirely feasible
with concrete. In building the aqueduct, the soft, fresh concrete is
placed against steel plate forms, or molds, erected in the trench or
tunnel, thus securing a smooth, clean surface for the water.
The pathway of the Catskill Mountain water from
the great Ashokan reservoir to New York City will have many an up and
down, and some of the "downs" will be deep. West of the
Hudson, several tributaries with broad valleys trend generally
northeasterly, so that the aqueduct has to cross these valleys. The
great river itself has to be passed, and east of it lies the
important valley of the Croton, and at the southerly end of the
aqueduct for about two miles even the high land is so low and the
real estate so expensive that a tunnel under light pressure is the
most economical type of conduit.
These valleys are so far below the natural
level at which the water will flow that it will have to be carried
across them under great pressure; for the valleys are much too wide
for the stone arch construction which the very mention of the Roman
aqueducts at once suggests, or for any other kind of bridge of the
great height necessary. The most permanent and economical form of
construction, therefore, is a tunnel through the solid rock, passing
not only beneath the visible streams, but also under the pre-glacial
gorges, now filled with earth and hidden from view. It is of the
utmost importance that these tunnels should be driven through strong,
sound rock, so that there will be not only no leakage of water, but
sufficient weight and strength to resist the pressure which the water
will exert due to its distance below the hydraulic gradient, or
natural flowing level, for cut-and-cover aqueduct.
Before these pressure tunnels could be
designed, a great deal of information had to be obtained about the
geology of the valleys. Hundreds of drill-holes, with individual
depths often of several hundred feet, and aggregating many miles, had
to be sunk through the earth into the rock in order to determine its
character at different points, as well as its depth, so that the
tunnels might be located safely, avoiding as far as practicable the
rocks which were too weak or difficult for tunneling. Of course it
has not been wholly feasible to avoid all these difficulties, but by
going to great depths, satisfactory conditions have been found.
Two of the most important and beautiful valleys
are those of the Rondout Creek and the Wallkill River. The Wallkill
valley was found to be very simple geologically, Nature being
satisfied with one kind of rock, through which tunneling will
probably proceed with no more than the ordinary difficulties. Rondout
valley, on the other hand, is somewhat of a geological museum,
containing at least twelve different kinds of rock, varying from the
hard quartzite conglomerate, locally known as Shawangunk grit, to
soft, waterbearing, and treacherous sandstones and limestones. Sound,
strong granite is found beneath the Hudson River and on both sides at
the selected place for crossing between Storm King and Breakneck
mountains, the picturesque northern gate of the Highlands of the
Hudson, about four miles above West Point.
Several years of hard work
will be required for driving and lining these tunnels. For the
Rondout siphon,1 besides the shafts at
each end, six intermediate shafts, making eight in all, have been
provided to aid in construction, so that the digging of the tunnel
may proceed at fourteen points. To aid in constructing the Wallkill
tunnel, four intermediate shafts will be used. Each of these tunnels
is about four and a half miles long. For the siphon beneath the
valley of Moodna Creek, stretching south to the Hudson River, five
miles long, there will be seven shafts. A shaft about 1200 feet deep
is thought to be necessary on each bank of Hudson. To cross beneath
the Croton reservoir, a tunnel with two shafts 510 and 560 feet deep
will be required. These pressure tunnels, aggregating seven miles in
length, will also be lined with the most substantial concrete
masonry. Inside this lining, the waterway will be, circular, with
diameters ranging from fourteen feet to sixteen and a half.
If to the new tower of the Metropolitan Life
Insurance Company, at Madison Square, New York, there were added the
height of a Fifth Avenue mansion, it would approximately equal the
depth (708 feet) of the shaft at the southerly end of the Rondout
siphon. Even in the shallower Wallkill siphon the cages carrying men
and materials up and down from the tunnel level will travel a
distance (in the deepest shaft, 480 feet, in the shallowest, 350
feet) greater than that from the sidewalk to the top of the towers of
the Park Row Building, for a number of years New York's tallest
building. From the bottom of each of the working shafts tunneling
will be extended for an average distance of nearly half a mile before
the headings from adjacent shafts will meet. When finished, each
tunnel will be large enough for subway train to pass through.
Pressure tunnels, being a more expensive type, have smaller waterways
than the grade tunnels, and the water will flow through them at
higher velocities.
Besides the great valleys to be crossed by
pressure tunnels, there are many others too narrow or of too
unfavorable geology to be crossed economically by tunnels. Steel
pipes, incased in concrete and lined with cement mortar, will be used
for passing these depressions. Three pipes will be laid across each
valley, but only one will be laid at first, the others being deferred
until the increase in the demand for water makes the expenditure
necessary. In general the diameters of the pipes inside the lining
will be approximately nine and a half feet north of Kensico
reservoir, and eleven feet south of that reservoir. At each end of
every siphon, and at every reservoir, there are to be buildings
containing appliances for controlling the flow of the water, known as
siphon-chambers and gate-houses. A total of seventy buildings for
this and other purposes along the aqueduct will be required. |
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Map of the Ashokan Reservoir
Typical Section Of Dike
Maximum Masonry Section Of The Olive Bridge Dam
Elevation Of The Concrete Bridge Designed To
Carry The State Road Across One Branch Of The Enlarged Kensico Reservoir |
The Ashokan reservoir (Ashokan is an Indian
name meaning "place of fish") will be situated about
fourteen miles west of the Hudson at Kingston, eighty-six miles in
air line from New York, and will center about the hamlet of Brown's
Station on the Ulster & Delaware Railroad. It will be formed by a
chain of masonry and earth dams having a combined length of over five
miles. Another dam about half a mile long will divide the reservoir
into two basins. It will be twelve and a half miles long, and the
average width will be a mile. When the reservoir is full, its water
surface will be 590 feet above tide; it will contain 128,000 million
gallons, sufficient to cover Manhattan Island to an average depth of
twenty-eight feet; 190 feet will be the maximum depth of water behind
the dams, and fifty feet the average throughout the reservoir. With a
shore-line of forty miles, it will have a water area of 12.8 square
miles, and a nearly equal additional area of land has been taken to
protect the margins. Approximately forty miles of new highway and
thirteen miles of new railroad will have to be built. A concrete arch
bridge at the dividing dam will afford connection between the
northern and southern sides of the reservoir. Seven villages and many
scattered dwellings and other buildings now dotting the valley will
have to be razed. From forty small cemeteries all the bodies in 2500
graves must be removed. All trees and brush will be cut and taken
away or burned. The landscape will be changed, but, guarded by the
somber mountains, Ashokan Lake will add to the attractiveness of the scenery.
Olive Bridge dam is the greatest of the chain
of dams. Nearly a mile long on top, it has a maximum height above its
foundation of 240 feet.Its central portion is being built of solid
masonry, with a top length of 1000 feet, minimum top width of
twenty-three feet, and a maximum width at the bottom of 190 feet.
This portion of the dam closes the main gorge of the Esopus. Concrete
core walls are being built in the earth dams. These earth dams, or
dikes, are thirty-four feet wide on top, and have flat slopes, so
that their thickness at the bottom is great, reaching a maximum of
800 feet in the earth portion of Olive Bridge dam. If all the earth,
rock, and masonry to be handled in constructing Ashokan reservoir
were to be put in one heap, they would form a pyramid having a base a
quarter mile square and of an equal altitude. The great pyramid of
Cheops, in Egypt, was originally 756 feet square at its base and 481
feet high. Its volume, therefore, is only one eighth that of the
material to be moved in building this one reservoir of the Catskill water-works.
Construction of the main dams of the Ashokan
reservoir was begun in the fall of 1907, the contract, amounting to
more than twelve and a half million dollars, having been awarded to
MacArthur Bros. Company and Winston & Company. To provide for the
thousands of laborers, many of whom have families, a great camp or
temporary town has been built close to the scene of operations. This
town has hundreds of houses, schools, a bank, a church, a hospital, a
water-supply system, a sewerage system with a disposal plant, a great
general store, a large bakery, a mess-hall, an office building,
blacksmith and machine shops, streets, park, band-stand, bathhouses,
ice-house, fire department, police, electric lights, and telephones.
Great quarries and sand-pits are being developed to furnish materials
for the dams, and ten miles of standard-gage railway, not to mention
several miles of narrow-gage, have been laid, connecting with the
Ulster & Delaware main line. For seven busy years Camp City will
flourish, and then it will be obliterated as completely as possible. |
Near historic White Plains, thirty miles north
of the New York City Hall, the valleys of the Bronx River and Rye
ponds afford opportunity, by constructing one large dam, to form a
reservoir of great capacity, approximately 40,000 million gallons,
with its water surface 355 feet above tide. Its watershed is
insignificant, but in it can be kept, relatively near the place of
consumption, a water reserve sufficient to insure against the
distressing results of accident to the aqueduct northward. Indeed, if
necessary, that part of the aqueduct could be out of service for
several weeks for inspection or repairs. Hence it also virtually
safeguards the continuity of the flow from the Ashokan reservoir
almost as well as if a duplicate aqueduct for these seventy miles bad
been built at much greater expense. To be sure, a second aqueduct
will be needed in the distant future, but the reservoir will continue
to perform this function of insurance toward the two. From Kensico
reservoir, also, in the future, additional aqueducts and pipes can be
led in various directions, to distribute water to different parts
arts of the vast district which, in all probability, will ultimately
be dependent upon it.
Kensico dam will be of massive masonry, 1830
feet long, rising 150 feet above the ground and nearly 300 feet above
its deepest foundation in the ledge rock underlying the valley.
Conspicuously in view from the four-track suburban line of the Harlem
Division of the New York Central Railroad, it will be the greatest
monument to the city's enterprise of all the Catskill water-works
structures. Ten years or more will be required for its building. |
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Completing The Arch Of A Section Of
Cut-And-Cover Aqueduct
Section Of Cut-And-Cover Aqueduct Near Peekskill
View Of The Spillway And Dam Of The Present
Kensico Dam |
Just north of the city line,
in Yonkers, on a large, flat-topped hill, will be built Hill View reservoir,2 an
equalizing reservoir of approximately 900 million gallons capacity,
to regulate automatically the differences between the steady flow in
the aqueduct from Kensico reservoir and the fluctuating consumption
in the city. This reservoir will be made by digging to an average
depth of about twenty-five feet (maximum forty-four feet) over a
large part of the hilltop, and using the earth thus obtained to build
the sides of the reservoir higher. Its water surface will be 295 feet
above tide, about 3000 feet long, and 1500 feet wide, and the water
will be thirty-six and one half feet deep. A great concrete wall will
divide the reservoir into two basins, and in this wall will be formed
a by-pass aqueduct, so that water can flow to the city without
entering the reservoir, whenever it may be necessary to clean or
repair the reservoir. The reservoir will be lined with concrete and
stone paving.
There will also be a by-pass around Kensico
reservoir. From the paths on top of the embankment of Hill View
reservoir magnificent views will be had of New York, the adjoining
towns, the Hudson with its Palisades, and the blue waters of Long
Island Sound.
From Hill View reservoir an extension of the
Catskill aqueduct will deliver the water into the distribution pipe
systems in the streets of the five boroughs of Greater New York. The
busy, congested streets, already underlaid with subways, water and
gas pipes, sewers, electric conduits, and other structures, and
bordered by tall buildings having one or more stories underground,
cannot well accommodate the great number of large pipes that would be
necessary to bring Catskill Mountain water from Hill View to the
consumers. Furthermore, the annoyances and dangers incident to
digging so many big trenches and laying the pipes in the streets
would be quite intolerable. If this pipelaying could be done quickly,
the bother might be endured; but it would unavoidably spread over
several years. Indeed, it might be said to be perennial, when repairs
and replacements are taken into the reckononing, and a main
distribution system of great pipes would be costly. Hence it is
deemed wise to avoid as far as practicable the use of steel or iron
pipes for the extension of the Catskill aqueduct for delivering water
into the city.
Beneath the borough of the Bronx, Manhattan
Island, and the edge of Long Island there is solid rock. Therefore a
way of escape from many of the pipe troubles appears. Starting from
Hill View reservoir, a great tunnel, like those under Rondout and
Wallkill valleys, is to be driven deep into the rock, hundreds of
feet below the street surface, and lined with concrete. Thus,
disturbance of the streets will be avoided, and a permanent conduit
will be secured. Shafts through which tunneling operations are to be
conducted will be spaced from 3000 to 5000 feet apart at points where
little inconvenience will be caused. After construction, these shafts
will be the connections between the tunnel and the main pipes of the
street distribution system. This tunnel will pass beneath the Harlem
and East rivers, but the crossing of the Narrows to Staten Island
will be made by heavy pipes, because the rock there is at too great a
depth, and the quantity of water too small, to make a tunnel worth
while. As a matter of precaution, two parallel pipes will be laid
beneath the water some distance apart, and a reservoir to contain a
reserve store of water will he built on high land on the island.
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The fountains of Versailles are famous, and
thousands make pilgrimages to see them in their beautiful settings
when the water is turned on. Two fountains of far greater volume --
scores of times as great -- will be incidental features of the
Catskill water-works. At times water in reservoirs, as in natural
ponds, becomes impregnated with unpleasant tastes and odors, due
mostly to very small organisms which, in a favorable combination of
conditions, develop in unusual numbers. Although. not deleterious, or
not seriously so, the products of these organisms are disagreeable.
Aeration has been proved by experience and experiment to be an
efficacious and inexpensive means for removing these tastes and
odors, and the most convenient form of aeration for the present
purpose has been found to be nozles of a simple design arranged as
fountain-jets. Of these great aeration fountains, one will be built
where the water is drawn from Ashokan reservoir and the other at
Kensico reservoir. In each fountain there will be upward Of 2000 jets
in symmetrical groups within a basin 500 feet long by 250 feet wide.
By using different combinations of these nozle groups, various
quantities of water, up to the full capacity of the aqueduct, can be
aerated. With appropriate landscape settings, these gigantic
fountains will be also a lasting source of enjoyment.
In order further to safeguard and improve the
quality of the water, filtration is to be provided, and northwest of
White Plains a site has been selected for a great sand-filter plant
which will be of about twice the capacity of the largest plant now in existence.
When all the works are completed, the Catskill
water-supply will be one of the safest in the world. Its
gathering-grounds are topographically and geologically of unusual
excellence and are sparsely populated. Wide marginal strips of forest
and meadow will protect each impounding reservoir. These great
artificial lakes will afford long storage for the gathered waters,
giving opportunity for the beneficial action of sun, wind, and
sedimentation. By these various means pollution will largely be
prevented, and objectionable bacteria, tastes, and odors will be
almost wholly removed or destroyed.
Goethe once wrote, "Dem Menschen ist ein
Mensch noch immer lieber als ein Engel."3
And so perchance the reader may be possessed of sufficient human
interest to inquire by what marshaling of men's brains and brawn
these great works are to be wrought. By appointment of Mayor George
B. McClellan, under special legislation, John A. Bensel, a civil
engineer, Charles N. Chadwick, a business man, and Charles A. Shaw,
formerly president of the Hanover Fire Insurance Company, constitute
the Board of Water Supply of the City of New York. They were chosen
from lists of three names presented respectively by the Chamber of
Commerce, the Manufacturers' Association of New York, and the Board
of Fire Underwriters. Mr. Bensel is president of the board, and
succeeded Mr. J. Edward Simmons, who resigned in January, 1908, and
is now president of the Chamber of Commerce.
Two bureaus comprise the board's forces. In the
Administration Bureau are the secretary, auditor, chief clerk, and
purchasing agent, adjuster of claims, and chief of aqueduct
patrolmen, each having a necessary corps of assistants, totaling for
the bureau about 125 persons. Consulting Engineer John R. Freeman is
the engineer adviser of the commissioners. At the head of the
Engineering Bureau is Chief Engineer J. Waldo Smith. On his staff of
consultants are Professor William H. Burr, Mr. Frederic P. Stearns,
Allen Hazen, George W. Fuller, and a few other engineers and
scientists of national and international reputation. Mr. Charles L.
Harrison is Deputy Chief Engineer. Because of the geographical extent
and the magnitude of the works, the Engineering Bureau has been
organized in four departments: the Headquarters Department, with
Alfred D. Flinn, Department Engineer, has charge of preparing designs
and specifications for the dams, aqueducts, and other structures;
executive and civil-service matters, inspection of manufactured
materials for construction, and preparation of realestate maps and
documents for all the departments, and in addition surveys and
construction within the city limits. The Reservoir Department, with
Carleton E. Davis at its head, is charged with all surveys and
construction on the watersheds. Its chief work at present is the
Ashokan reservoir, with its great dams and the headworks of the
Catskill aqueduct. From the headworks to the divide of the Croton
watershed sixty miles of Catskill aqueduct is under the care of the
Northern Aqueduct Department, Robert Ridgway, Department Engineer, to
whom falls the Hudson River crossing and the great siphons under the
Rondout, Wallkill, and Moodna valleys. The remainder of Catskill
aqueduct, with Kensico and Hill View reservoirs and the filters,
falls to the Southern Aqueduct Department, with Merritt H. Smith as
Department Engineer.
The departments are divided into three or more
divisions, which in turn are subdivided into several sections.
Including engineers, inspectors, stenographers, clerks, laborers, and
other assistants, the Engineering Bureau contains nearly 1000 persons.
For purposes of construction, the work of
building the reservoirs and aqueducts has been divided into many
contracts, ranging in expenditure involved from a few tens of
thousands of dollars to several millions. In the busiest summer, when
the majority of these contracts will be simultaneously in progress,
the contractors' employees will probably reach a total of 15,000 and
the expenditure will approximate $2,000,000 per month. This autumn of
1909 will doubtless see 10,000 men at work, for by October the major
contracts for the aqueduct will have been let, excepting part of the
line between Kensico and Hill View reservoirs. Hill View reservoir
will probably also he under contract; the main dams of the Ashokan
reservoir are already in progress. A re-estimate of the cost of the
Catskill project made since many of the large contracts were awarded
shows that the original estimate of 1905 was sufficient, an unusual
and gratifying fact in engineering projects of great magnitude.
Readers distant from New York may ask: "Why
go so far for water? Why not take water from the Hudson, a
relatively short distance above the city, just as many inland
communities do from rivers on which they are situated?" Simply
because the Hudson is a tidal estuary as far as Troy, and if
sufficient water to supply even half the needs of New York were
withdrawn in extremely dry seasons, the river water would be too
brackish for domestic consumption as far north as ten or fifteen
miles above Poughkeepsie, or eighty miles in air line from the City
Hall, New York. It is only six miles farther to the head of the
Catskill aqueduct. To be certain of maintaining an adequate fresh
water flow, large compensating reservoirs would have to be built on
the head,waters of the river in the Adirondack Mountains to store the
surplus waters of wet seasons for discharge into the upper
tributaries of the river at a suitable rate in dry seasons.
Furthermore, much unpurified sewage enters the river above any point
at which the city's works could be located. Since the water would be
taken at tide-level, it would have to be raised several hundred feet
by powerful pumps in order to deliver it in the city under suitable
pressure. Hence, to obtain Hudson water, purify it, and convey it to
the city, extensive and very costly works would be necessary; and
when all was done, the supply would be inferior in quality. It has
been said that the nineteenth century discovered dirt -- that is to
say, the true nature of filth and its relation to human health. In
the light of that discovery, communities are learning to prefer clean
water, if such is available. Consequently the Board of Water Supply,
with the concurrence of other city authorities and the approval of
the State Water Supply Commission, very sensibly concluded that it
was more economical and prudent to take some of the Hudson water from
some of the lower tributaries in the Catskill Mountains before it
became contaminated, and at an elevation from which it could flow by
gravity to the city and be delivered at a level 165 feet above that
at which the Croton water is delivered.
An abundance of clear, soft, pure, and
wholesome water is the most fundamentally essential commodity for any
great community. New York City has expended to date for the
construction of existing water-works, exclusive of interest and
maintenance, about $137,000,000, not taking into account the
investments of private water companies, several of which still purvey
to portions of some boroughs. Recent projects for additional supplies
from the Catskill Mountains and Suffolk County will involve during
the next half century the expenditure of about $225,000,000 and will
increase the safely available daily supply to two and a half times
that now available, and provide bountifully for the city's needs as
far in the future as can be reasonably foreseen. And the Croton,
Ridgewood, Catskill, and Suffolk County systems will be permanent,
even if long continuance of the city's remarkable growth should in
the distant future lead to a demand for water in excess of the
combined capacities of these sources.
New York's present population is 4,500,000 and
her daily consumption of water for all purposes from works owned by
the city is, as I have said, 125 gallons per person. At this rate, a
year's supply would be a lake twenty miles long, three miles wide,
and having an average depth of twenty-five feet. The ordinary summer
flow of the Niagara River over the American Falls is now about 8000
million gallons daily, which is only fifteen times the stream
consumed in New York. It must be remembered that Yonkers, Mount
Vernon, New Rochelle, and even more distant suburbs may be added to
the metropolis, or at least to the metropolitan water district, in
the not far distant future, making yet greater demands upon the
water-works systems built by the city, and many local sources of
supply will have to be abandoned because of insufficiency and
pollution. With all these vast figures representing demand and
expenditure, it is comforting to find by computation that the average
cost of all water for domestic, public, and manufacturing uses each
day to each person will be less than one cent, including maintenance,
interest on capital investment, and sinking fund.
Of the great works for collecting and conveying
the Catskill Mountain water, many of the most difficult and
interesting parts will be totally hidden from view after completion.
Indeed, of the Catskill aqueduct scarcely anything will be visible
except the long, neatly graded embankments over the cut-and-cover
portions and the occasional buildings housing the gates and other
devices for controlling and measuring the water. Most conspicuous
will be the great reservoirs, with their huge dams of masonry and
earth. Many of these visible structures will be comparatively
inaccessible. It is fitting that these conspicuous structures should
be made esthetically pleasing, not by elaborate and expensive
ornamentation, but by simple and dignified treatment. Here the
dominant civil engineer will be aided and guided by the architect and
the landscape engineer.
Subterranean river! The mere name has always
held a mysterious and romantic fascination. A reversed subterranean
river is what the Board of Water Supply is creating. Instead of
beginning with tiny streams in dark fissures of the rock or some
surface rivulets which sink out of sight, this river will start at
its large end from the Ashokan reservoir, an extensive artificial
lake, and flow for scores of miles without change of volume, coming
to the light only in the beautiful Kensico Lake and Hill View
reservoir's huge bowl, whence it will ramify through the hundreds of
miles of tunnels and pipes beneath the city streets, issuing finally
through faucets and hydrants in thousands of jets to serve those who
have bidden it flow thus in constraint. Several years of very active
work must, however, elapse before Esopus water will reach the city.
Notes
1) By way of explanation,
aqueducts, or conduits, beneath valleys are frequently called
inverted siphons, or simply siphons, because of their similarity to
true siphons turned upside down. Of course there is no siphonic
action. <BACK>
2) London dedicated in the
spring of 1909 Honor Oak reservoir, a covered masonry reservoir 824
by 587 feet, occupying, with its embankments, fourteen and a quarter
acres. Hill View reservoir will be 3000 feet long and 500 feet wide,
and will occupy, with its embankments, 163 acres. Ultimately Hill
View reservoir will have a concrete, groined-arch roof, supported by
pillars of concrete.<BACK>
3) "To mankind men are
always dearer than angels." <BACK>
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