THE WORLD'S GREATEST
AQUEDUCT
WATER FROM THE CATSKILL MOUNTAINS
TO THE
CITY OF NEW YORK
BY ALFRED DOUGLAS FLINN
Harper's Monthly1909
Engineer, Headquarters Department,
of the Board of Water Supply of the City of New York
THE Catskill Mountain water system being constructed
for New York City is one of the most notable engineering enterprises
ever undertaken. Ranking with the inter-oceanic canals at Suez
and Panama, the Assuan irrigation works in Egypt, and the projects
which are converting western America's and 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.
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.
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.
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. 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
dams is a mixture of Portland cement, sand, 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, continuing 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,
water-bearing, 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, (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.) 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 the Hudson. To cross beneath the Croton
reservoir, a tunnel with two shafts 510 and 560 feet deep will
be required. These pressure tunnels, aggregating seventeen 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 a 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, encased 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.
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.
Camp CityConstruction 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 had 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 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.
Just north of the city line, in Yonkers, on a large, flat-topped
hill, will be built Hill View reservoir,(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. Hillview reservoir will be 3000 feet long and
1500 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.) 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 pipe-laying 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 reckoning, 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 be built
on high land on the island.
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
volumescores of times as greatwill 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 nozzles 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 nozzle 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." (To mankind men are always
dearer than angels). 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 real estate 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 be
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 headwaters
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.
Catskill Legacies
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