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I




GENERAL LIBRARY
UNIVERSITY OF MICHIGAN.
THlE
liagerman Collection
OP BOOKS RELATINQ TO
HISTORY AND POLITICAL SCIENCE
SOUQHT WITH MONEY PLACED BY
JAMES J. HIAGERMAN OF CLASS OF '61
IN THE HANDS OP
Professor Charles Kendall Adams
IN THE YEAR
1883.


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Hubert 0. Thor.isun,3
NEW YORK WATER SUPPLY.
DEPARTMENT OF PUBLIC WORKS.
REPORT
OF
HUBERT 0. THOMPSON, COMMISSIONER OF PUBLIC WORKS,
TO THE
HONORABLE WM. R. GRACE,
MAYOR OF THE CITY OF NEW YORK,
ON
Proposed New Aqueduct and Storage Reservoir for
Additional Supply from Croton River,
WITH DETAILED REPORT OF
ISAAC   NEWTON,
CHIEF  ENGINEER  OF THE  CROTON  AQUEDUCT,
AND
OPINIONS OF CONSULTING ENGINEERS.
NEW YORK, FEBRUARY, I882.




I




DEPARTMENT OF PUBLIC WORKS.


DEPARTMENT OF PUBLIC WORKS,
COMMISSIONER'S OFFICE, NO. 31 CHAMBERS STREET, ~
NEW YORK, February 23, I882.
Honz. WILLIAM R. GRACE, Mayor.
SIR-In the quarterly and annual report which I transmitted to
you on the I3th instant, I stated that under the direction of Mr. Isaac
Newton, Chief-Engineer of the Croton aqueduct, with the assistance
of Mr. E. S. Chesbrough, as Consulting Engineer, careful investigations and surveys have been made during the past year, to ascertain
the best method of securing an additional water supply for the city;
that these investigations and surveys have led to a definite plan for a
new aqueduct from the Croton river to the city, the outlines of which
I briefly stated; that upon examination the plan has received the
approval of Mr. John B. Jervis, the distinguished constructor of the
Croton aqueduct, Mr. James B. Francis, President of the American
Society of Civil Engineers, and that it was also examined and
approved by Mr. Robert K. Martin, under whose direction a similar
work, the Baltimore water-works tunnel, was recently successfully
constructed. I have now the honor of transmitting to you ChiefEngineer Newton's report of the proposed plan, with the opinions
and approval of the eminent engineers who have examined it in all
its various features.
The facts and circumstances which have led to the immediate
necessity of another aqueduct or conduit to bring a large additional
supply of water to the city have been so often stated in previous
reports of this Department, and they are so fully understood and
appreciated by you, and I believe by the greater part of the people
of this city, that they need no repetition here.
The only questions which remain open for discussion are, as to
the source from which the supply should be obtained, and the means
of collecting it and conveying it to the city.




iv


I believe there is no difference of opinion among engineers and
others who have given the subject attention and study, that in regard
to geographical position, quality of water, and facility of means for
conducting the water to the city, the Croton river and water-shed is
the most desirable' source of supply.
The only consideration which has led to the suggestion of other
sources, is a supposition that the Croton water-shed cannot be relied
upon to furnish enough water at all times for a new aqueduct of the
required capacity.
Let it be shown that this supposition or fear is groundless, and
there can be no hesitation in rejecting, for very obvious and potent
reasons, the propositions of obtaining pure fresh water from the upper
Hudson river, from Lakes George, Erie, Ontario, or Champlain, from
the Passaic or Hackensack rivers in New Jersey, from the Housatonic
river in Massachusetts, or Connecticut, or from the streams in Rockland and Orange counties.
The project of using the salt water which surrounds the city, as an
auxiliary to the city's water supply, continues to be brought forward
from time to time, by persons who have evidently not given the subject sufficient consideration. The objections to it are so apparent and
conclusive, that engineers do not consider it worthy of serious consideration.
In view of the many questions. however, which are put to me by
citizens, why we do not propose or make preparations to use salt
water, I will briefly state the objections to it.
We have now 512 miles of iron pipes, with 5,427 stop-cocks, and
6,496 fire-hydrants, to distribute the Croton water in the streets of the
city. To make the salt water of real service for the very limited
purposes for which it can be used, it would be necessary to duplicate
the greatest part of the distributing system, and to erect and maintain
pumping machinery and stand pipes, at a total cost of probably not
less than twelve to fifteen million dollars. Considering that less than
five per cent. of the present water supply is used for extinguishing
fires and for cleaning streets, the principal or almost exclusive uses to
which salt water can be put, the cost of a salt-water system, as compared with any of the new projects for an additional fresh-water
supply of ample proportions, is so enormous as to place it out of the




V


question on that ground alone. But there are other serious objections
to it. The fire underwriters say that salt water used in extinguishing
fires would be likely to do as much damage to merchandise as the
flames themselves. The rapid corrosion of iron pipes along the riverfront, where they come in contact with salt water, shows that it
would soon corrode the mains, stop-cocks, and hydrants, and, in the
opinion of the Chief of the Fire Department, wear out the steam fire
engines. For use on the streets it is so objectionable in a sanitary
point of view, that several years ago the Board of Health prohibited
and forbade street sprinkling with salt water.
An additional fresh-water supply will not only accomplish all that
can be attained by utilizing salt water, but will meet the many other
equally important objects of an adequate water system, for which
salt water would be useless. The salt-water plan may, therefore, be
dismissed without further reference.
The supposition or fear entertained by many that the Croton
water-shed is not capable of furnishing a constant supply for a new
and large aqueduct, shows an imperfect knowledge or misconception
of the facts. Accurate observations and measurements of the rain-fall
and of the quantity of water running over the Croton dam for the
past sixteenyears, prove that in the driest of these years, i88o, the
average daily flow of the Croton river was 250,000,000 gallons. All
that is needed to secure that supply every day in the year is sufficient
storage capacity.
The capacity of the Croton water-shed to furnish a mininum supply of 250,000,000 gallons per day being proven, the whole question
is narrowed down to the selection of the plans and means to secure
sufficient storage and to conduct the water to the city.
Chief-Engineer Newton's plan covers both the subject of storage,
and that of a conduit from the Croton river to the city. In regard to
storage it combines in the highest degree the merits of simplicity,
efficiency  and economy.  Instead of constructing a number of
smaller reservoirs on the slopes of the Croton water-shed, on sites
established by surveys made under the direction of the Croton Aqueduct Board in 1857-58, it is proposed to build a dam on the Croton
river at Quaker Bridge, about 414 miles below the present dam, and
5 miles above the mouth of the river, forming a reservoir of 3,635




vi


acres in area, with a storage capacity of about 32,000,000,000 gallons
above the level of the proposed new aqueduct.
The advantages of this single reservoir as compared with a number of smaller ones in the upper portion of the water-shed are:
1st. It will receive the entire drainage of the 361 square miles of
water-shed, including about 23 square miles below Croton lake, not
included in any previous reports, plans, or calculations; on the other
hand, the combined drainage area of a sufficient number of smaller
reservoirs on the sites heretofore selected, to contain 32,000,000,000
gallons available water, would be less than 200 square miles. Consequently the large reservoir would fill much more rapidly than the
smaller ones.
2d. The estimated cost of building this reservoir is $4,000,000
being at the rate of $I25 per one million gallons capacity.
The cost of building the smaller reservoirs was estimated by my
predecessor, the Hon. Allan Campbell, in his report of August 12,
I879, at $200oo per I,000,000 gallons or $6,400,000 for a storage
capacity equal to the large reservoir.
3d. Purity of water is better secured by large reservoirs than by
smaller ones.
4th. By taking the proposed site the length of aqueduct required
to convey the water to the city is shortened about ten miles, as compared with the plans proposed in I875.
Though the dam is to be of unusual height, and will have to resist
the weight of a very large body of water, the eminent and experienced engineers who have examined the entire plan pronounce it
entirely practicable, as well as the best that can be adopted. Dams
of nearly the same height have been successfully built and used in
France and elsewhere.
The conduit from the dam at Quaker Bridge to the Harlem river at
High Bridge, is to be a masonry aqueduct, circular in shape, twelve
feet in diameter, and capable of delivering about 250,000,000 gallons
of water per day. The Harlem river and Manhattan valley are to be
crossed by syphons, and the remainder of the conduit between the
Harlem river and the Central Park reservoir is to be in tunnel wherever possible. The distance from Quaker Bridge to the Harlem




Vll


river, on the line selected, is 262 miles, only 9-o00 mile greater than
an air line; it is ten miles shorter than the Sawmill river line, and 9Y
miles shorter than the Bronx river line surveyed in I875 under the
direction of General Fitz John Porter. It has the further most valuable
advantage of being almost wholly in rock tunnel, thus securing the
greatest possible strength and stability of the structure, with the least
cost for supervision and maintenance after it is completed.
The prominent features of the entire plan are:
Ist.  Large capacity and facility for collecting and storing
water. The new reservoir will receive the entire drainage of the
Croton water-shed, and hold 32,000,000,000 gallons of water above
the level of the aqueduct, and can therefore supply 200,000,000 per
day for I60 days without recourse to the flow of the river. With the
9,000,ooo,ooo gallons of water in existing storage reservoirs and lakes,
and 5,000,000,000 gallons in the new reservoir about to be built on
the east branch of the Croton, the total available storage capacity will
be 46,000,000,000 gallons, sufficient to supply 200,000,000 gallons
per day for 230 days.
2d. Large capacity and utmost attainable strength and security of the
conduit to convey the water to the city. The new aqueduct will be
capable of delivering 250,000,000 gallons per day, the entire minimum
drainage of the Croton water-sheds. This will supply a population of
2,500,000 at the rate of oo00 gallons daily per capita, or 3,300,000 at
the present rate of consumption (about 75 gallons daily per capita).
Add to it the capacity of the present aqueduct, I00,000,ooo gallons
per day, and we can, if needed in the far distant future, convey to the
city that amount of water fro.n the Housatonic river, or any other
proposed auxiliary to the Croton, and supply a population of
4,660,000 at the present rate of consumption.
3d. Economy of first cost of construction, as well as subsequent
supervision and maintenance.
The cost of the new dam, reservoir, and aqueduct,
as above described, including everything necessary to deliver the water into Central Park reservoir is estimated at.......................... $I4,000,000 00




viii


The cost of a new aqueduct of 150,000,000 gallons
daily capacity by one of the two routes surveyed in 1875, with equal storage capacity as
included in the new plan, and provision to deliver
the water in the Central Park reservoir, is estimated as follows:
Sawmill river route.. -...........
Bronx river route....................
Cost of new plan per 1,000,000 gallons of conduit
cap acity..............................
Cost of plans reported in 1875 per 1,000,000 gallons
conduit capacity:
Sawmill river route..................
Bronx  river  route..................


$19,493,000 00
20,119,000 00
48,o000oo oo
103,946 oo
108,121 00


The substitution of one large reservoir in place of eight or ten
smaller ones, distributed over the entire water-shed, and the construction of the shortest practicable conduit, with the greatest proportion of rock tunnel, will involve much less labor for supervision
and maintenance of the works after completion than the works proposed under any other plan.
In conclusion, I can only repeat what I stated in my last quarterly
report, that the character and reputation of the eminent engineers
who have been engaged in the preparation and elaboration of this
plan, and in its examination, is a guarantee that their conclusions give
the best results which patient investigation, guided by professional
ability, experience and judgment can secure.
Very respectfully,
HUBERT 0. THOMPSON,
Commissioner of Public Works.




NEW YORK WATER SUPPLY.
Department of Public Works.
HUBERT O. THOMPSON, COMMISSIONER.
__- 4 — ------
REPORT
OF
ISAAC NEWTON,


Chief Engineer of Croton Aqueduct,
ON PLANS PROPOSED FOR STORING AND CONVEYING AN ADDITIONAL
WATER SUPPLY TO THE CITY.
OPINIONS OF THE CONSULTING ENGINEERS.
TABLES OF RAIN-FALL, ETC., ETC.
MAP SHOWING DRAINAGE AREA AND AQUEDUCT LINES.
NEW YORK:
MARTIN B. BROWN, PRINTER AND STATIONER,
49 AND 51 PARK PLACE.
X882.




I




TABLE OF CONTENTS.
-. -—.  -.
PAGE
Report of Chief Engineer................................................  5
Opinion  of Consulting  Engineer..................................................  ooo
APPENDIX, OPINIONS OF THE CONSUITING ENGINEERS, ETC.
O pinion  of John  B. Jervis.......................................................  23
Opinion  of James B. Francis.....................................................  27
Opinion  of  Robert  K.  M artin.....................................................  31
Report and Estimates of the Sawmill river and Bronx river plans.................... 33
Estimate for conveying water from north side of High Bridge to Central Park reservoir... 4
Table I. Showing waste of water over Croton dam................................. 42
"  2. Average depth in Aqueduct and average delivery in gallons per day........... 45
"  3. Rain-fall in Croton basin................................................ 47
"  4. Rain-fall at receiving reservoir, High Bridge, Fordham, Tarrytown, Sing
Sing, Croton  Dam, and  Boyd's Corners.................................  49
"  5. Comparison  of rain-fall at different places................................  52
(  6.  Rain-fall at North  Salem, Croton  basin...................................  53
"   7. Extract from report of Dr. Daniel Draper for I876; drought of I876..........  55
"  8. Rain-fall receiving  reservoir, Central Park................................  57
"  9. Rain-fall at W est Point..........................................................  59
" I. Storage drawn in I880 and  88..................................................... 61
(   I.  Existing  storage, artificial and  natural.....................................  62
"  12. Per cent. of rain-fall running  in  the  Croton................................  63
Map showing drainage areas and aqueduct lines...........................to face page 63




0




NEW YORK WATER SUPPLY.
E=iEs IPO ET
TO
HUBERT O. THOMPSON,
Commissioner of Public Works,
BY
ISAAC NEWTON,
Chief Engineer, Croton Aqueduct.
CHIEF ENGINEER'S OFFICE,        1
NEW YORK, January 30, I882.
Hon. H. O. THOMPSON,
Commissioner of Public Works:
SIR-I beg leave to present the following report of the result of
the investigations and surveys made under my direction since my
appointment as Chief Engineer, for a new aqueduct from the Croton
river to New York. The surveys and maps previously made,
together with other data on record, have been of great value, not only
in the positive information they afford, but in the suggestions they
have led to.
Surveys for an additional supply made since the construction of
the present aqueduct, have been those of the Croton water-shed of
I857-58, and those made in 1875 under General F. J. Porter, for the
Sawmill river and Bronx river plans. The description and estimates
of the cost of construction for both these plans will be found in
Appendix " A," attached to this report.
At the beginning of my study of the subject of bringing additional
water to the City of New York, the various sources from which it has




6


been proposed to obtain this supply were carefully looked into.
These sources are the Croton, the Passaic, the Housatonic, and the
Hudson and Hackensack rivers, and Lakes George, Erie, Ontario
and Champlain, also the streams in Rockland and Orange counties.
The use of wells and salt water to be raised into reservoirs by pumps
for auxiliary supply was likewise considered.
All the sources, i. e., from these rivers and lakes, with the
exception of the Croton and Housatonic, were set aside as being out
of the question on account of the immense cost, or uncertainty of
sufficient supply; although some of them might be used as auxiliaries.
Since becoming satisfied that the Croton river is by far the most
available and the most economical source of supply, I have simply
endeavored to determine the best plan for storing and conveying the
water of this river to the city.
The quality of the Croton as a pure and wholesome water, as well
as the geological and other characteristics of the river basin are so
well understood, that nothing on the subject need to be mentioned.*
The meteorological history of the water-shed of the Croton, as far
back as there are any records, shows that with adequate storage
capacity at the head of the aqueduct, an average daily supply of
about 250,000,000 t of, gallons can be relied upon in the driest years.
The area of over 23 miles which will be added to the existing
water-shed-i. e., to the area shown on the water-shed maps of
I857-58-by the plan to be hereinafter described, would increase
the average daily supply from I5,000,000 to 20,000,000 of gallons,
thus making the total average daily supply of about 265,000,000 to
270,000,000 of United States gallons.4
The following views have formed the basis of my investigations
and have led to the conclusions arrived at:
Ist. The Croton water-shed is adequate to furnish all the city will
need for many years to come, provided adequate storage capacity
is provided.
2d. The storage reservoirs must ultimately be of sufficient capacity
to hold all, or nearly all the water of the Croton in the driest years,


* See Report, App. "A."
t See rain-fall and other tables in Appendix.
t The utmost safe capacity of present conduit is about Ioo,ooo,oco.




7


so that none, or but very little, can waste over the dam. And
eventually to carry over a portion of the surplus of wet years to
supply the deficiency of dry ones.
3d. The nearer the storage reservoirs to the entrance of the
aqueduct, if they are of sufficient capacity, the greater will be the
quantity of water that can be gathered from the entire Croton basin,
and the more rapidly will the reservoirs fill again after being drawn
down. The time required to fill the existing storage reservoirs and
lakes, after they have been drawn down, is a warning on this point
which should be heeded. All the water which falls on that part of
the basin situated below the several storage dam sites shown on the
maps of.857 and I858, above what is necessary to supply the
aqueduct, will run into the Hudson river over the waste-weir of the
aqueduct dam, unless storage is provided at that point; so without
a reservoir at that locality, it will be impossible to secure storage in
the dry years. Hence storage located at the entrance to the aqueduct
is in the most advantageous position.
4th. The aqueduct capacity should be sufficient to convey all the
water available from the Croton valley; it should also be enough to
convey a portion of the water from other sources of supply, which
can be led into the Croton basin.
The capacity of an aqueduct Io feet in diameter, with an inclination
of I foot to the mile, is about I68,ooo,ooo of gallons in 24 hours;
while the capacity of an aqueduct 12 feet in diameter, with the same
inclination, is no less than 270,000,000 in the same time. The
excess of cost of the 12 feet over the Io feet conduit is believed to
be of much less importance than the greater capacity obtained.
5th. The aqueduct as far as possible should be in tunnel, this
construction being the safest, most durable, and the least exposed to
malicious damage. The difference in the cost between tunneling and
excavation, because of the improved appliances now available, has
been greatly reduced since the Croton aqueduct was constructed;
and the saving in length of conduit which can be effected by tunneling
over a construction on a line located on or near the surface of the
ground, added to the decreased land damages, will probably make the
former fully as economical even in first cost.
6th. Wherever it is necessary to cross depressions in the line, the




8


aqueduct should be carried on masonry laid in mortar, or beneath the
surface by syphons.
7th. Storage in the Croton basin is preferable to bringing water
from the Housatonic for the purpose of providing against deficiency
in the natural flow of the Croton.*
LOCATION OF NEW AQUEDUCT DAM.
It is evident this dam must be on one of three general sites: 1st.
It may be above the present dam. 2d. The present dam may be
used or another built immediately below it so as to raise the level of
the Croton Lake. 3d. It may be on the river considerably below the
existing Croton dam and embrace an additional drainage area to that
which now supplies the city.
As to the first site, taking that chosen by the surveys of 1875 to
be the most eligible for this locality. It is 5 68-Ioo miles above the
entrance to the existing aqueduct. Here the topography of the
country is such that it is not practicable to raise the dam sufficiently
above the grade of the proposed aqueduct to make a reservoir which
would store any considerable amount. A large area of country would
be flooded merely to get water into the aqueduct, and large portions
of this area would be shoal water.
The plans of 1875 contemplated a dam 30 feet higher than the
present one, with no storage above the level required to keep the
aqueduct full.
Those plans require Io.6 miles on Sawmill river route, and 13 98-Ioo
miles on the Bronx to be in tunnel, and would increase the length of
the aqueduct from its commencement on the Croton to the High
Bridge 3 2 I-I00 miles more than the present one, and nearly Io miles
more than the line located this year.
An aqueduct might be supplied from the level of the present lake,
and about I3   miles above the present dam near Trout brook, and
join the new line near the Pocantico river, making the length of
conduit to High Bridge about 273^ miles.
* Should the Croton basin ever prove inedequate to supply the city, it is possible that a
supply may be obtained within the State of New York by crossing the Hudson by tunnel near
Croton Point. When the time arrives this no doubt will be carefully examined before it is
finally decided to construct conduits from other sources.




9


Take next the secondc site, near the present dam. It is regarded
as impracticable to raise this dam, and the valley immediately below
is not well adapted for another of much greater height. These plans
moreover, would be inadequate without the construction of large
storage reservoirs on the various branches of the Croton to secure a
full supply of water for the aqueduct.
Take the third site; a considerable distance below the present
dam. An examination of the Croton river below this point to the
Hudson, pointed out an apparently favorable dam site near Quaker
Bridge, about 4 50-100 miles below the Croton dam, provided a rock
foundation could be found.
The geological characteristics of the valley and the sinking of pits
led to making surveys for a dam at this place.  The top waterline for the reservoir, or lake, as it would truly be, was run at 200
feet above mean tide, Croton grade. The present Croton lake is
I66 17-100 feet above same datum. Calculations based upon these
surveys show that the reservoir would contain over 32,000,000,000
of United States gallons of storage, above the level, necessary to
supply an aqueduct capable of conveying about 250,000,000 per
day to the city; or with a delivery of 200,000,000 per day
(twice our present supply), the aqueduct would be supplied for I60
days without a gallon from the natural flow of the Croton. The
existing storage in reservoirs and lakes is 9,ooo,ooo,ooo; the reservoir which will be begun in the spring, in order to place the full
daily supply of I00,000,000, the full capacity of present aqueduct,
beyond all doubt, and which is to contain about 5,00o,0oo,ooo, would
make the total storage nearly 46,000,000,000 of gallons; sufficient
to keep up a daily supply of 200,000,000, for nearly 230 days without the natural flow of the Croton.
The great area, 3,635 acres, and great average depth of this new
Croton lake would make it exceedingly valuable as a settling basin.
The benefits of such a condition of the water supply can scarcely be
overestimated, and hence the earnest efforts to take advantage of
them.
The dam now proposed is a work that would have been
considered, at the time of the construction of the present
aqueduct, of too great magnitude to be undertaken. The remarkable




I0


progress of engineering since then makes such a structure the most
advisable in this case. Successful works of the same character in
France have given great satisfaction, and confirm fully the theories
on this subject of Messrs. Montgolfier and Delocre, of France, and
Professor Rankine, of England. The estimate of the cost of this
dam, has been based upon no untried principles, but upon those
so ably advocated by the eminent engineers above mentioned, and so
signally justified by actual experience.
It may here be mentioned that stone dams of nearly this height
have existed in Spain for a long time, and have been proposed
elsewhere. In fact, we find, that as far back as I835, a dam I50
feet high was proposed near the mouth of the Croton, for an
aqueduct to supply this city. That dam, however, as far as the
existing plans show, was entirely different in character from the one
now recommended, not being in accordance with the principle so
successfully carried out in France. Besides, it did not provide for
any important amount of storage above the level of top water in the
aqueduct; whereas, the great value of the one now recommended
consists in storage capacity, sufficient to furnish 200,000,000 gallons
daily for i6o days. Without this capacity it would probably be much
cheaper to draw the city's supply from the present Croton lake.




I I


AREA AND CAPACITY OF PROPOSED NEW
QUAKER BRIDGE.


CROTON LAKE NEAR


ELEVATION *
ABOVE
MEAN TIDE,
FEET.




30
40
50
6o
70
8o
90o
110
120
130
140
150
i6o
170
i8o
190
200


I


No. OF ACRES.
7I37
37
55
146
201
262
334
398
417
562
649
733
1,245
1,756
*   2,412
3,037
3,635


CUBIC FEET,
NOT INCLUDING
CROTON LAKE.
2,230,000
14,080,000
31,690,000
58,850,000
105,600,000
169,96o,ooo
253,790,000
360,730,000
488, 1 60,000
639, 130,Ooo
819,007,000
1,026,860,000
1,261,540,000
1, 600,140, 000
2,222,350,000
2,994,590,000
3,966,930,000
5,130,740,000


U. S. GALLONS,
NOT INCLUDING
CROTON LAKE.
16,680,400
105,318,400
237,041,200
440,198,000
789,888,000
1,27I,300,800
1,898,349,200
2,698,26o,400
3,651,436,800
4,780,692,400
6,126)643,600
7,680,912,800
9,436,319,200
12,417,847,200
16,623,178,000
22,399,533,000
29,672,636,400
38,377,935,200


Your predecessor, the Hon. Allan Campbell, an engineer of
large experience, and who gave great attention to the water supply
in his report of August I12, i879, referring to the storage reservoirs
laid down on the water-shed maps of i857, says:" It is estimated
"that the average cost per million gallons of all reservoirs projected
" in the Croton basin will be $200, " and in the same report,
referring to the storage capacity required for the proposed aqueduct
* Croton datum.
f The area of present Croton lake is included after the level of present dam is reached.




f 2


of 1875: " To supply another aqueduct with I50,000,000 daily,
" also on the basis of the driest years, additional storage to the
" amount of about 30,000,000,000 gallons must be provided,"
which would then make the cost of the necessary storage
$6,ooo,ooo.
When it is remembered that the reservoirs projected in the Croton
basin would flood for the most part fertile valleys, probably the best
land in Putnam County, $200 per i,ooo,ooo gallons can hardly
be considered too large an estimate for the total expense of all
kinds necessary for impounding water. If a reservoir can be built on
the site above pointed out and contain, as above stated, 32,000,000,000
of storage, the city can then afford to expend nearly $6,500,000
for such a work considered as a storage reservoir dam.
Owing to the sterile and rocky character of most of the land this
reservoir will flood, as well as its vast dimensions as compared with
the size of the dam, it is estimated as hereinafter stated that the total
cost of the reservoir, including dam, will not be over $4,000,000.
But the storage it will contain is not the only advantage of a
reservoir of this capacity, and located in this place.
Ist. It saves nearly 1o miles in length of aqueduct over the
location of dam made in 1875, and this saving would go far towards
paying the whole cost of this reservoir.
2d. It is at the lowest end of the drainage of the Croton, and would
collect water more rapidly and completely than other plans.
3d. It would add about 23 square miles to the area of the watershed, equivalent to an average daily supply of from 15,000,000 to
20,000,000 of gallons.
4th. It would afford a settling basin of the grandest proportions;
the loss would be much less from evaporation and other sources on
account of greater average depth. It would avoid conveying the
water through miles of rivers, brooks, and, in many cases swamps,
before it reaches the aqueduct, while in very cold weather the supply
from such sources might be wholly cut off by frost, as was the case
(with the water from the storage reservoirs) in the winter of i880-81.
The difference in the cost between a dam and land necessary to
raise the water near Quaker bridge I42 feet above tide-which is
the level necessary to fill the aqueduct-and what would be necessary




I3
1)


to raise it 200 feet, is estimated to be about $2,000,000. Hence the
cost of the storage for 32,000,000,000 would be about $60 per million
of gallons, instead of $200, the cost per million by building on the
sites far up in the Croton basin; or $2,000,000 instead of $6,400,000,
for the same amount of storage, even if it could be collected in
reservoirs higher up in the basin, as laid down on the Water-shed
Map.
STORAGE.
The water-shed survey executed in I857-58, as before stated, was
made chiefly for the purpose of selecting the most available sites for
storage reservoirs.
The following table contains a list of the sites then selected,
together with other information of the utmost importance in studying
this subject in order to reach a safe determination respecting the
quantity of storage that can be secured in the Croton water shed by
those reservoirs.




'4


RESERVOIR SITES.
Table -from Water-s ked Map of i857-58 of Croton Basin above the present Croton
Aqueduct Dam.


RESERVOIR.I


A.....
B......
C......
D......
E......
F......
G.....
H...........
J......
K......
L......
M......
N......


Acres.
485.-00
192.00
730.00
i, oo8. oo
303.-00
600.-75
452.1I9
384.67
449.00
191.-38
51I2.-74
262.75
492.25
I97.00
239.47


0.
Gallons.
5,211,015,625
1,701,835,337
6,589,101,562
9,033,632,812
3,369,206,85 7
6, 120,335,937
4,861,035,156
2,490,062,500
4,205,820,654
2,314,074,703
5,671,449,219
2,328,217,733
4,392,131,445
1,676,049,171
2,182,337,109


Sq. Miles.
20. 45
15.2000
13.-7100
41.-9500
20.3700
12.5100O
20.9045
75.-4574
70. 5230
11.9I7I
78.9000o
26.8600
23.-3449
30. 9620
17.31P70


I.0
0.
Fee.
64
0.9
74
72
6o
90


I-I
Fee.
70
54'
545
33't
1,311
7570
925
1 1,170


Feet.
12,300
6,ooo
i16,600
21,000
7,500
io,6oo
12,200
14,748
12,745
14,809 t
13,12
12,300
8,650
7,629


Miles.
9.500 1
12.750
14.300
20.250
23. 750
15.500
i8.700
I9.390
20.447
28.710
15.215
i6.539
13.831I
7.708
9.970


r. 1 a.o   a)
V    V
S-.  I U  I


Feet.
390
500
550
500
600
56o
375
375
415
500
2.75
295
316
250
305


Entire drainage area of Croton Basin, 338 82-Iso square miles.
The total drainage area of all these reservoirs foots up 480.30
square miles, while the entire area of the Croton basin is 338.82 square
miles; this is because 'the computed drainage of some of the
reservoirs overlaps that of others, which shows that the Croton
Aqueduct Board did not contemplate that all of these sites could be
made available as reservoirs to the extent indicated by this table.
The drainage of some of them is so small that in a dry year they
probably would not fill; for example, reservoir F, which has a




5


drainage area of but 12 51-IOO square miles with a capacity of 6, I20,ooo,ooo gallons. An inspection of this map shows that if every one
of these reservoirs were built they would not receive the drainage of
over about 200 square miles, because they do not furnish storage for
the waters of large areas for which reservoir sites have not been found.
The total estimated capacity of these reservoirs is 62,000,000,000 of
gallons; of this amount 8,230,000,000 is already secured by
reservoirs E and G, which have been built, one at Boyd's Corners,
the other on the middle branch of the Croton; this leaves 53,770,000,000 as the remaining storage, assuming the drainage to be
adequate to fill the  reservoirs.  It has been estimated that to
supply another aqueduct on the basis of the driest years, with
I50,ooo,ooo daily, additional storage to the extent of about
30,000,000,000 must be provided; but as before stated, if all these
reservoirs could be built they could only receive the drainage of
about two-thirds of the Croton basin. The balance of the drainage
above the quantity necessary to supply the conduits would find its
way into the Hudson over the waste-weir of the dam, if not
secured near the mouth of the Croton. It is extremely doubtful if
even 30,000,000,000 gallons could be secured beyond all peradventure by constructing storage reservoirs in the water-shed many
miles above the entrance of the aqueduct. In short, the only way to
secure the entire flow of the Croton in the driest years, is to have
large storage capacity near the mouth of the river.
THE HOUSATONIC AS A FEEDER FOR NEW AQUEDUCT.
As stated in the quarterly report for August, I879, surveys were
made for diverting the waters of the Housatonic into the Croton
water-shed as a feeder for a new and large aqueduct. The plan
proposed for conveying this water to the Croton, in general terms,
was mainly an open canal with a sectional area of So square feet, and
an inclination of one foot to the mile, the calculated capacity being
Ioo,00o,ooo  gallons daily.  The comparison  of this plan of
obtaining water for the new aqueduct with that of storage has been
carefully studied in all its bearings.
The Housatonic is in Massachusetts and Connecticut, out of the
authority of this State, which could, therefore, exercise no control over




it, to prevent pollution, or enforce any regulations. The water would
have to traverse about eighty miles with exposed surface before
reaching the aqueduct, and in very cold weather there would be great
danger of the supply being cut off or greatly diminished when the
demand would be greatest.
This river is no doubt liable to the same fluctuations of volume as
the Croton, and there is no probability that in a season of extreme
drought I00,000,000 per day estimated could be obtained; but if it
could, the damages to mill rights would doubtless swell the cost much
beyond the estimate. It would be necessary not only to pay for all
rights injured below the point of intake, but for preventing mill
owners above from holding back water nights and Sundays during
seasons of drought. The yield of the Croton basin averaged during
August, 1878, 123,000,000 of gallons daily; in December, 1880, its
average was but 33,000,000, showing a falling off of 73 per cent. This
proportion applied to the Housatonic shows that it could not be
relied upon to furnish more than 54,000,000 a day, because the available area of the Housatonic basin is only about double that of the
Croton. If the lowest daily yield of the Croton be taken, now known
to be only about o0,000,000, then the Housatonic could not be relied
upon for more than about 20,000,000 daily.
The following table gives an estimate of storage required to supply
conduits with 300 millions daily, supposing a year as dry as that of
1880, the driest yet known in the Croton Basin.
For May...............................  3,797,500,000 gallons.
For June...........................     5,962,500,000
For July..........................  6, 130,560,000
For August.............................  6,200,000,000
For September......................... 6,ooo,o00,00o
For October......................   6,200,000,000
For November........................     5,820,000,000
For December..........................  6, 47,ooo,ooo000
Drawn from storage reservoirs............ 8,530,000,000
54,787,560,000 gallons.




17


Existing storage ponds and reservoirs............. $9,000,000,000
Quaker Bridge reservoir........................ 32,000,000,000
Reservoir I, to be built.....................  5,000,000,000
Still required..............................   9,000,000,000
55,000,000,000
If the difference in cost was in favor of the Housatonic plan, as
compared with that of constructing storage reservoirs on the Croton,
the disadvantages the former presents are so great as to be decisive
against it.
HEAD OR LEVEL OF THE NEW SUPPLY IN NEW YORK CITY.
It is seen by the description of the Sawmill river and Bronx river
plans, that the aqueduct proposed was to end near Jerome Park,
3 oI-IOO miles from High Bridge and 7 88-Ioo miles from the receiving reservoir in the Central Park. At Jerome Park there was to be
constructed a receiving reservoir of 600,000,000 gallons capacity.
The elevation of the new aqueduct at Jerome Park was to be 30 feet
higher than the present one; but a small proportion of this increased
head would be available in the circulation on Manhattan Island,
because the water was to be conveyed from Jerome Park reservoir to
High Bridge and from thence under the Harlem river to the Central
Park reservoir in cast iron pipes 48 inches in diameter.
If ten lines of pipes of this diameter were laid for this purpose it
is calculated that the loss of head or pressure from friction alone
would be about 20 feet, when the aqueduct is discharging its full
capacity, by the time the water reached the south side of Harlem
river. As the main discharge would be into the Central Park reservoir, the pressure at which water could be delivered from that source
would not be increased.
The new works, wholly independent of the Croton, now being
constructed, to convey the waters of the Bronx and Byram rivers will
deliver water into reservoirs to be built at William's Bridge at an
altitude of about I8o feet above tide, or about 50 feet higher than the
present aqueduct, and the water which will be supplied from this


2




i8


source will suffice for the more elevated portions of the Twenty-third
and Twenty-fourth Wards.*
No provision has been made in the Quaker Bridge plans for
additional storage reservoirs within the city limits. The principal
function of such reservoirs is to keep a supply in the city in case it is
necessary to shut off the aqueduct. Hence the necessity for storage
at this end will not be increased by building another aqueduct.
Any important change, with the view of raising the level of the
top water-line of the Central Park reservoir, would involve great
expense, and could not in any event materially diminish the high
service area necessary to be supplied by pumping.
THE   AQUEDUCT.
Several lines have been run in order to get the best location for
an aqueduct, as far as possible in rock tunnel, from the Quaker
Bridge reservoir to the High Bridge. A favorable line was found
which measures 26' miles to High Bridge, or only about 91-Ioo mile
greater than an air line.
This line is remarkable for the comparatively small depth of the
shafts necessary for constructing the tunnels, which is a matter of
great importance, both with respect to the cost and time required to
execute the work.
There would be required 33 shafts, averaging IOI feet in depth,
between the entrance of the aqueduct and the High Bridge.
It is proposed to cross the Harlem river by a syphon, either
tunnel through rock, or pipes laid on river bottom; to cross Manhattan Valley by a similar syphon, and to build the rest of the
aqueduct between the south side of Harlem and Central Park reservoir in tunnel wherever possible, the same as in Westchester County.
It is proposed to make the aqueduct a circle in sections lined with
brick, 12 feet in diameter, and to have it leave Quaker Bridge reservoir of New Croton lake at the level of about 142 feet above tide, thus
permitting 58 feet of storage to be drawn, and to discharge into the
Central Park reservoir at II9 feet above the same datum.
Acres.
* Area of Twenty-third and Twenty-fourth Wards, New York City.................  12,317
Number of acres below Ioo feet mean tide, Croton datum, to be supplied from aqueduct 8,352
Number of acres between Ioo and I6o feet, to be supplied from Bronx.............. 2,617
Number above I60 feet, to be supplied from Yonkers or by pumping................ I,348




19


Such a conduit would have the capacity to deliver about
250,000,000 of United States gallons daily when filled to within a
few inches of the top.
I need hardly call attention to the great advantages a conduit in
tunnel presents over any other mode; such a construction would be
as imperishable as any structure can be, and it is no small matter
that it would be removed as far as possible from the danger of injury
by evil-doers.
In preparing plans and making estimates for this conduit, I have
had the invaluable aid of unrestricted access to all the plans and
other data connected with the construction of the Baltimore aqueduct
tunnel from Gunpowder Creek, kindly granted me by Robert K.
Martin, the Chief-Engineer of the work. As this tunnel is in rock,
and of the same size and character as the one herein proposed, we
have a safe guide for estimates of cost. While the Croton tunnels are
considerably longer in the aggregate than the Gunpowder (Baltimore)
tunnel, they would have shafts of much less average depth and
could consequently be worked more rapidly and advantageously.
TIME REQUIRED TO COMPLETE THE PROPOSED WORK.
The time required to construct the Baltimore tunnel may be taken
as a guide in estimating the time necessary to complete the proposed
Croton tunnels; as the drifts in the proposed work would be about the
same length and through the same character of rock, while the shafts
would be considerably less in depth, it can be executed in less time,
other things being equal. Taking the most difficult section on the
proposed line as the portion which would require the most time, and
which would consequently govern the completion, it is estimated that
the New York aqueduct can be constructed in three and a half years
from time of commencement. It should be remembered that in
tunnel construction the work would be carried on day and night,
winter and summer.
It is more difficult to estimate the time which would be required to
complete the dam; it would probably be found necessary to suspend
the work during the winter, say from three to four months each year;
but when this dam has reached the height of 135 feet above mean
tide, or ii9 feet above the ground, Croton datum, it can be made
to supply the new conduit with about ioo,ooo,ooo gallons per day;




20


it is probable with a systematic prosecution of the work, it can be
raised to this height in three and a half years, while a year and a half
more would probably complete the work to the full height.*
The estimated cost of the proposed aqueduct from Quaker Bridge
reservoir to the receiving reservoir in the Central Park is $o0,000,000.
As before stated, in making these estimates, I have had the aid of
the experience gained in the construction of the Baltimore tunnel;
the above estimate being based largely on that data, and on liberal
prices for both labor and materials, it is believed that it may confidently be taken as the amount within which the work can be done.
The proposed dam would be constructed wholly of masonry;
were it not for the contingencies which may arise in securing a proper
foundation, a very close estimate could be made of its cost. This
being the case, and with the knowledge of the ground obtained by
over one hundred test pits and explorations with diamond drills, I
have estimated an amount for the dam and reservoir hereinbefore
described which should place it beyond contingencies. The estimate
for the dam and reservoir is $4,0ooo,ooo, which, added to the estimate
for the aqueduct, would make the cost of the new water supply
$I4,000,000. The details of these estimates are ready for your
inspection.
I estimated early last summer that an aqueduct of I5o,ooo,ooo
daily supply, with the necessary storage capacity, could be built for
$12,000,000; subsequent examination has shown that such a work
could be constructed for less than that amount. But increasing the
size of conduit to convey 250,000,000 per day, instead of 150,000,000,
the total cost was augmented somewhat over $2,000,000; the excess
in cost was considered small to expend for an additional daily supply
of I00,000,ooo of gallons.
With such an aqueduct in use and with pipes already laid, it is
safe to say that the head (or pressure) which existed when the Croton
water was introduced would be again enjoyed, provided the waste
does not exceed the present amount. It is expected that the Department will be able to diminish the waste.
* The Furens dam in France, 164 feet high, was completed its full height in four years.
t Should the dam owing to unexpected difficulties in the foundation cost one, or even
three millions more than the estimate, the Quaker Bridge plan would still retain its decided
superiority.




21


The following tables-give the comparative cost and other particulars of the three plans mentioned in this report:
Table of Comparison of the Plans which have been proposed for an Aqueduct from the Croton
Basin; with Extension frolm Iigh Bridge to Central Park Reservoir..........._                _


QUAKER BRIDGE, I SAWMILL RIVER. BRONX RIVER.
188I PLAN.     1875 PLAN.    1875 PLAN.._ —       -  I                         _


I.  Total length,  miles...................
2. Capacity in million gallons daily.........
3. Total storage provided by plan in Croton
basin, with dams just high enough tol
fill aqueduct, million gallons daily....
4. The same with dams, full height proposed,
millions of gallons..................
5. Total cost including no provision for
storage............................
6. Total cost including provision for 32,000,000,000oo   storage...................
7. Cost of providing 32,000,000,000 gallons
storage in Croton basin..............
8. Area of new lake including present Croton
lake, acres......................


31.35


250


* 42.31
150


* 41.17
150


a


32,000
t $12,000,000
14,000,000
2,000,000
3,635


t $13,o93,414  t $13,719,529


~ 19,493,414  ~ 20, I19,529


6,400,000
1,200


6,400,000
1,200


-- --
-----


* From profiles.
t Estimate for aqueduct to High Bridge $Io,ooo,ooo, for dam without storage $2,ooo,000 (see page 41)
= 12,000,003.
t Estimate in Appendix "A " added to Mr. G. W. Birdsall's estimate (Appendix "B") for conveying
the water to Central Park reservoir, by the plans contemplated in 1875.
~ The same as No. 5, with $6,400,oo0 for storage added.
7able of Comparison of the Plans which have been proposed for an Aqueduct from            Croton
Basin, terminating at High Bridge.


QUAKER BRIDGE SAWMILL
PLAN, 1881.    PLAN,
I. Total length from  the Croton to High
Bridge, miles......................       26.51
2. Capacity, U. S. gallons in 24 hours,i
millions............................       250
3. Total cost with no additional storage.....  $10,000,00  * $9,1
4. Total cost with 32,000,000,000 additional
storage in Croton basin..............  t 12,0ooo,ooo  15,5
5. Cost per million of gallons of supply
obtained, including 32,000,000,o00 additional storage in Croton basin.......   48,000        I
* See estimate in Appendix " A."
t Estimating increase in height of dam for storage to be $2,ooo,ooo, see page 13.
t Adding cost of 32,000,000,000 storage at $200 per million.


_. -


RIVER  BRONX RIVER
1875.    PLAN, 1875.


36.52


I5o
91,989
91,989
03,946


36.08
150
* $9,818,104
t I6,2I8,104
io8,121




22


A large amount of field and office work has been accomplished
during the season, among other things, the flow-line of Quaker Bridge
reservoir, 78 miles, and 2I3 miles of cross section lines have been
run; over IOO miles have been run in Westchester County. A great
deal of detail survey has been done to determine the proposed dam site,
besides other surveys of a similar character; 78 borings to rock have
been made in Harlem river above High Bridge. The data obtained
from the U. S. Geodetic and Coast Survey has been a valuable aid in
topographical work along the line of proposed aqueduct.  We
have had the advantage of the trigonometrical points and the detail
surveys made under the late Professor Bache by the officers of the
Coast Survey. Over I00 test pits have been put down on the proposed dam site, and two diamond drills are accomplishing good
results in the bed of the Croton.
I have studied the entire subject with the aid of E. S. Chesbrough,
Consulting Engineer. B. S. Church, Resident Engineer, from his long
experience with the existing works has rendered valuable aid. The
topographical work has been under the immediate charge of John
Mechan, formerly of U. S. Coast Survey.
I am indebted to J. W. Adams for assistance in making up the
estimates, as well as details of plans of aqueduct on which they were
based.
Very respectfully submitted.
ISAAC NEWTON,
Chief Engineer.
NEW YORK, January 31, I882.
ISAAC NEWTON, Esq.,
Chief Engineer Croton Aqueduct.
DEAR SIR-I concur with you in the views and recommendations
of your report on the proposed additional supply of water for this
city.
E. S. CHESBROUGH,
Consulting Engineer.




APPENDIX.
—._^. ---OPINION OF JOHN B. JERVIS, ESQ., CONSTRUCTOR OF
THE CROTON AQUEDUCT.*
ROME, N. Y., January 13, I882.
To ISAAC NEWTON, Esq.,
Chief Engineer Croton Aqueduct, New York;
DEAR SIR-I acknowledged your favor of Ioth December, I88I,
also that of December 26, I88I. In the meantime I visited your
office in New York, and obtained a knowledge of the general features
of the plans and estimates of the proposed improvements for the
supply of New York City with water. After full consultation with
yourself and your Consulting Engineer, I now propose to reply to the
questions you have propounded to me.
FIRST QUESTION.-As to the Necessity of an Additional Supply of
Water.
As to this question, it does not appear necessary to go much into
detail. For several years instead of adding to the supply as population increased, the over strained capacity of the present aqueduct has
been the same, and no addition has been practicable to the supply
needed for the largely increased population.
A serious failure in the present aqueduct, which has been a source
of anxiety for several years, may arrest its functions.
New York has a very large shipping interest, that needs much
water; since the introduction of the Croton, her manufactures have
largely increased; she is reported now the largest manufacturing city
in the United States.
The present population is too large to depend for its current
supply of water on one aqueduct. Without further discussion of this
* Condensed by Mr. Jervis from his longer report.




24


question, I have no doubt that the important interests of the city
demand an additional conduit.
SECOND QUESTION.-Source of Supply.
I noticed by the reports you gave me that surveys have been
made, establishing the practicability of obtaining the supply from the
Housatonic river in Massachusetts and Connecticut.  Whatever
feasibility there may be of drawing from this or any other source, it
appears to me better that it should be held in reserve until the
supply from the Croton valley is exhausted.
THIRD QUESTION.-Position of Reservoirs for Storage-Importancc
of having them Large and well down the Stream.
No doubt, large reservoirs are to be preferred and the nearer the
lower end of the valley, the more effectual will they be to secure
the whole drainage of the basin. The securing of large reservoir
sites, instead of several small ones, is decidedly important in securing
pure water. The high dam at the lower end of the valley certainly
provides for the most efficient method of securing the entire drainage
of the Croton valley.
FOURTH   QUESTION.-Practicability of a High Stone Dam-Its
Safety-Precautions to be Observed, Means of Passing Flood
Water during Construction of the Foundation-Height of Main
Dam above Flow-line —Length of Waste-weir and Height of Water
to be permitted above Flow-line during and after Greatest
Storms.
As to general practicability, I have no doubt; but it will be a
high dam, so far as can now be judged, about 230 feet above rock
bottom, or I80 feet above surface of ground. You may require to
go lower to secure a rock foundation for the highest part; your
soundings not being complete, I do not think you will have to go
materially lower than now appears probable.
There will be no difficulty in making a wall of hydraulic masonry
sufficient to sustain it against the power of the water above from
overthrowing it.
The main question will be the power of the material to resist the
crushing force of this weight.




25


I think you will have no difficulty in obtaining stone in the
vicinity of the location that will sustain the pressure. Good brick
will bear near four times the weight without crushing. I have no
hesitation in expressing the opinion that the Ulster cement, with clean
sand, will make mortar and concrete sufficient for this work. If you
can find cement that is stronger, it will be prudent to use it in the
lower section of the dam.
Means of Passing Floods during Construction.
The floods of the river will, no doubt, embarrass the work of
construction, and as this will be a work of years, the precautions
should be very efficient. Such a work cannot be executed without
many contingent embarrassments, and you will find occasion for the
most vigilant assiduity and your best professional judgment will be
demanded.
The Height of Dam above Flow-line-Length of Waste-weir and
Heigiht above Flow in Floods.
The old dam has a waste-weir of 270 feet. In about 40 years since
its construction, no flood has been reported except in one instance of
a rise of 8 feet above the crest of the dam.
If I understand the location, and I have no doubt it was well
explained to me, the facilities for a waste-weir in the proposed dam
are very good. Its position will be in the subsidiary dam that is
required north of the main dam, where the waste-weir and the
channel from it will be in solid rock.
FIFTH QUESTION.-Conduit in the Tunnel as much as possible,
instead of an Embankment or in slight Excavations.
There can be no question that a conduit in a tunnel through
solid rock will be more safe, and require less repair than one on any
kind of filling or in light cuttings.
In some cases the cost of filling in low grounds would be greater
than that of tunnel in sound rock.
SIXTH QUESTION.-Difference in Cost of Conduit of, say,  50,000,ooo daily and one of, say, 200,000,000 to 250,000,000 not Equal to
the Value of the Increased Capacity.
It would require more calculations than I am now able to make, to
determine what the difference of value may be. There is, however.




26


no doubt the largt aduiit will be less expensive, as compared to
capacity, than the smaller one.
SEVENTH QUESTION.-Level of Central Park Reservoir to be Maintained in New Works, but General Head throughout the City to be
greatly improved by Additional Supply, probably without New
SMains at first.
The new aqueduct will greatly improve the facility for keeping full
head in the city reservoirs, and consequently maintain more
efficiency in the pressure on the distribution pipes. Whether an
increase of the city mains may be found necessary, will depend on
the experience of the effect of a full head in the reservoirs.
EIGHTH   QUESTION.-Danger to a City of the Importance and
Magnitude of New York, of depending wholly on one Aqueduct.
As to the propriety of a second aqueduct there can be no doubt.
Finally, I would say:
ist. The dam you propose, is practicable.
2d. That it is the best, and, in fact, the only plan that can secure
the whole source of the Croton valley for the supply of its waters to
the City of New York.
3d. Furnishing, as it does, a reservoir of large capacity, it provides
a supply of water of the purest condition practicable.
4th. Though there will be more or less embarrassment from the
floods of the river during construction, there is no reason to doubt
they may be successfully overcome by the engineering skill you will
be able to exercise on this subject.
5th. As to line and plan of aqueduct you propose, I see nothing
to suggest. Your view of this I regard as well taken.
When the dam is carried to the height of the gate chamber, you
can occupy the new aqueduct, should it be ready. This you will see.
With sincere wishes for your success in the construction of this
rather bold, but eminently important and, as I believe, quite
practicable work, I submit this paper.
Very respectfully,
JOHN B. JERVIS,
Consulting Engineer.




27


OPINION OF JAMES B. FRANCIS, ESQ., PRESIDENT OF
AMERICAN SOCIETY OF CIVIL ENGINEERS.
ISAAC NEWTON, Esq.,
Chief Engineer of Croton Aqueduct:
DEAR SIR-In reply to your communication of the Ioth instant,
requesting my opinion of the advisability of obtaining an additional
supply of water for the City of New York, by the plan you describe,
I have to say that, in addition to the brief description in your communication, I have been informed verbally by yourself and Mr. E. S.
Chesbrough more fully on the subject; have read various printed
reports and documents relating to the general subject of the water
supply of the city; examined the maps, plans, and profiles of proposed plans in your office, and have made a personal examination of
the site of some of the proposed works.
From information gathered as above, I beg leave to offer the
following remarks on the several parts of the plan described by you:
Ist. To go to the Croton watershed for the additional supply.
Every year there is a waste of water from the water-shed much
greater than the quantity now supplied to the city.
This can be made available, to a great extent, by additional
storage reservoirs of sufficient capacity.
The alternative is to divert a supply from the Housatonic river,
by means of a canal and tunnel into the Croton valley, estimated to
cost, with the damages to the mill property on the river, about
$2,500,000.
The canal provided for in the estimate I consider quite insufficient
to provide for the obstruction to the flow from ice.  I should recommend it to be made of much greater depth than proposed, with
walled sides, instead of earth slopes, for at least part of the depth.
As the canal would be about 30 miles long, this would add largely
to the cost. I also consider the estimate of damages to the mill
property much too low.
The Housatonic river being in another State would be, as you
suggest, a very serious objection.




28


Your estimate of the cost of sufficient storage on the Croton river
is $4,ooo,ooo. The cost of the Housatonic plan, in my judgment,
would not be very much less than this.
There being no great saving in cost, the want of jurisdiction, to
my mind, points decidedly to the Croton water-shed as being the
proper source of supply.
2d. " To build a masonry dam on the bed rock near Quaker
" bridge on the Croton, about 4'2 miles below the present dam, and
" thereby raise the water level to 200 feet above tide."
3d. " This reservoir thus made, to contain about 32,000,000,000
"gallons of storage above the line which will keep water I i' 5" deep
"in an aqueduct I2 feet diameter."
This dam would be nearly 200 feet high in the highest
part, and would be a work of great magnitude, but I think entirely
practicable, and as it would include a larger water-shed than reservoirs
higher up the river, and create an available storage capacity of
32,000,000,000 of gallons at an estimated cost of $4,000,000, or at the
rate of $125 * per million gallons, it would appear to be the most
economical mode of obtaining storage in the Croton water-shed.
In the report of the Commissioner of Public Works for the quarter
ending June 30, i879, "it is estimated that the average Cost per
million gallons, of all the reservoirs projected in the Croton basin,
xvill be $200."
A point to be considered in a reservoir of this elevation and
magnitude, is the probable loss from percolation, elsewhere than at
the dam; the geological formation appears to be very favorable in
this respect, but I think there would be some loss. I should expect,
however, that the additional water-shed, which would be obtained at
the proposed site, over that at the site of the present dam, would
fully compensate for this loss.
4th. " To run the aqueduct from the dam to High Bridge as far
as possible in tunnel, and to avoid embankments whenever
" possible."
The experience with the present Croton aqueduct is so clearly and
distinctly in favor of avoiding embankments, and constructing either


* This includes cost of dam to full height.




29


in tunnel or open cutting,-that I do not see that anything more need
be said on that point.
5th. "To cross the Harlem river by a syphon, either tunnel
through rock or pipes laid on river bottom; to cross Manhattan
"valley by a similar syphon, and to build the rest of the aqueduct
between High Bridge and the Central Park reservoir in tunnel
"wherever possible."
6th. " To raise the gate-house at the present dam to suit the new
" water level, and to thoroughly strengthen the present aqueduct
"between this and the new dam."
7th. " When the new aqueduct is completed to rebuild those
"portions of the present structure on embankment where it has shown
"signs of weakness."
I am not sufficiently familiar with the localities to express an
opinion on all these points.
Crossing the Harlem river by a high bridge I think should be
avoided if possible, as being too much exposed to injury. Either of
the modes you suggest would be far better in this respect, and I have
no doubt much less expensive.
The thorough repair of the present aqueduct as soon as the new
one is in successful operation, is no more than ordinary prudence
would require.
Comparing the several plans to which you have called my
attention:
New aqueduct on the Sawmill river route with a new dam across
the Croton river, one-quarter of a mile above the head of Croton
lake; length from dam to High Bridge 36.52 miles, o0.06 miles being
in tunnel; the supply to be derived from new reservoirs in the Croton
basin:
Estimate of cost of conduit and pipe work.......... $8,700,000 00
Cost of 32,000,000,000 gallons of storage capacity at
$200.......................................  6,400,000 oo
$15,I 00,00 00




30


New aqueduct on the Sawmill river route with new dam as above;
the supply to be derived from the Housatonic river:
Conduit and pipe work as above................. $8,700,000 oo
Estimate of cost of supply. from the Housatonic, as per
report of the Commissioner of Public Works for
the quarter ending June 30, I879, $2,500,000; as
stated above I consider this too low, for the
present purpose say.........................  $3,500,000 oo
$12,200,000 00
By the plan you propose, called the Quaker bridge plan, the
estimate is as follows, the estimate for the conduit for comparison
with the other plans, being for a capacity of 150,000,000 of gallons
per day, the same as for the preceding, requiring a conduit of not
more than ten feet diameter:
Dam and land damages for reservoir.............. $4,000,000 oo
27 miles of conduit............................  8,028,000 oo
$12,028,000 00
In view of the great objection of deriving the supply from a source
not within the jurisdiction of the State of New York, I think the choice
would lay between the two plans deriving the supply from the Croton
water-shed.
By the above estimates the cost would be much less by the plan
you propose than by the Sawmill river plan, and I see no advantage
that the latter plan would have to compensate for its increased cost;
of the three plans considered as above, I have no hesitation in recommending the Quaker bridge plan as being the most advisable one
to adopt.
Very respectfully,
JAMES B. FRANCIS.
LOWELL, MASS., December 30, i88I.




31


OPINION OF ROBERT K. MARTIN, CHIEF ENGINEER
(NEW) BALTIMORE WATER SUPPLY.
BALTIMORE WATER DEPARTMENT,
CHIEF ENGINEER'S OFFICE, CITY HALL,
December 30, I88I.
ISAAC NEWTON, Esq.,
Chief Engineer, Croton Aqueduct:
SIR-I had the honor to receive from you a communication, dated
December I4, I88I, containing your conclusions upon an additional
water supply for New York City.
Having examined the maps, plans, profiles, and reports relating to
the matter, and after having made a personal inspection of the site of
the proposed dam near Quaker bridge, and a careful study of the
subject, I beg leave to present the following report:
By reference to a " table showing waste of water over the Croton
dam," it will be seen that a large amount of water annually goes to
waste in the Croton water-shed.
This waste, if stored, would be more than enough for your present
wants, and will be sufficient in the future, for a largely increased
consumption.
Again, the Croton water-shed is the nearest large supply to your
point of delivery.
These facts influence me in saying that the most available source
from which to obtain an additional water supply is the Croton watershed.
In order to store the water of the Croton water-shed, you propose
building a masonry dam on bed rock near Quaker bridge, 4' miles
below the present Croton dam, and thereby raise the water-level in
the Croton basin to 200 feet above tide, which will give a storage
capacity of about 32,000,000,000 gallons.
In my opinion a dam of such a height as you propose should be
of masonry laid in hydraulic mortar, which, in the hands of competent engineers, I believe to be,entirely practicable. My own views
are fully sustained by the experience of French engineers, with
similar dams, of nearly the same height.
You propose to build an aqueduct from the dam at Quaker
bridge to High bridge, as far as possible in tunnel, and to avoid
embankments wherever possible.




32


An aqueduct is the main artery of a water supply, and should be
located where it will be safe and give the least trouble in the future.
In my opinion, the best location for an aqueduct is in tunnel,
where practicable.
The form of an aqueduct that I would recommend should be
circular, the diameter sufficient to preclude the possibility in the
future of wishing that it had been larger.
Harlem river and Manhattan valley can be crossed either with a
tunnel or by pipes, laid on the river bottom, or beneath the surface.
There can be no difficulty in the raising of the gate-house, at the
present Croton dam, to suit the higher water-level, and also strengthen
the present aqueduct between the present Croton dam and the
proposed new dam.
After your new aqueduct is completed, you can rebuild those
portions of the present aqueduct, or embankment, where it has shown
signs of weakness.
I consider that no large city should be dependent on a single
aqueduct for its water supply.
Your plan of constructing a large storage supply at Quaker bridge is
preferable to the building of storage reservoirs in the upper Croton basin.
These storage reservoirs, in the upper Croton basin, can be
availed of in the future, when the storage at Quaker bridge becomes
inadequate. The Housatonic plan, as a source of supply in place of
storage, has objections. It is located in an adjoining State, where it
will be difficult to exercise control over pollutions, or enforce
regulations.
Furnishing a city with pure water through an open canal, at all
seasons of the year, and guarding every avenue of pollution along its
line, is a serious problem.
Is it not possible that the Housatonic will be subjected to the
same diminution of flow as the Croton during a drought, and may
you not, eventually, have to resort to storage, to keep up this supply?
After a careful study of the whole subject, I feel confident that
the plan recommended by you is not only advisable, but the proper
one for an additional supply of water for New York City.
Respectfully submitted,
ROBERT K. MARTIN,
Chief Engineer.




33


"A A.
REPORT ON SAW MILL RIVER AND BRONX RIVER
PLANS.
DEPARTMENT OF PUBLIC WORKS,
ENGINEER'S OFFICE, CITY HALL,
NEW YORK CITY, January 3, 1876.
Hon. FITZ JOHN PORTER, Commissioner of Public Works:
SIR-In compliance with your instructions, two surveying parties
were organized under Mr. Charles J. McAlpine and Mr. Horace
Loomis, to ascertain the best route for another aqueduct between the
Croton river and the Harlem river, at High bridge.
These parties were placed under the charge of Mr. Thomas A.
Emmett, who for the last four years has had charge of the reservoirs
in the Croton valley, and whose report of the surveys and the estimated cost of the new aqueduct is hereto annexed. A careful examination of the Croton river was made, showing the most favorable place
for another dam was about a quarter of a mile above the head of the
Croton lake and just below the mouth of the Muscoot river. It is at
this point proposed to raise a dam 30 feet above the lip of the
present dam, which will form a reservoir and settling basin covering
about 800 acres, and will be about seven miles in length and hold
about 1,180,000,000 gallons.
Surveys for the aqueduct were made across the divide to the head
waters of the Bronx, and down that valley, and also further to the
west to the Pocantico and Sawmill rivers.
The length of the aqueduct from the reservoir to the High bridge,
on the Bronx river route, will be 36.08 miles, and by the Sawmill
river route 36.52 miles.
The aqueduct will start from the Croton river with an elevation of
thirty (30) feet above the present aqueduct, and descend on a grade
of 12.67 inches per mile to the vicinity of Jerome Park, at which point
the high grounds fall away so far as to render the continuance of the
aqueduct of masonry expensive and objectionable.
It is here proposed to construct a reservoir, and from this point
carry the water in cast-iron pipes. The water in the reservoir will


3




34


stand forty-two (42) feet above that of the waters in the reservoirs
in the Central Park.
The estimate is based on an aqueduct of sufficient capacity to
carry 150,000,000 gallons per day, which, with the present aqueduct
carrying Ioo00,000ooo,ooo will give a daily supply of 250,000,000 gallons.
The drainage area of the Croton basin, above the Croton dam, is
338 square miles.
In the report of the Croton Aqueduct Board, made to the Common Council in I863, they estimate the daily flow of the Croton river
at 338,832,I28 gallons.
Mr. Tracy, late Chief Engineer of the Croton Aqueduct, in his
report in May, I873, says: " For many years past the Department
has kept a gauge of the daily quantity of water flowing over the
Croton dam, in addition to that which is conveyed to the city by the
aqueduct, and during the past ten years an average daily quantity of
340,000,000 gallons has run to waste over the dam, in addition to the
quantity that was brought to the city."
Professor Chandler, President of the Board of Health, who has
made the Croton a special study, says of it: " We have an available
supply of 387,000,000 gallons." Of the purity of the Croton water, he
says: "The character of the Croton water-shed is of a nature to
" guarantee water of the best quality.  Mountains and hills of Lau"rentian gneiss receive the rain-fall, which is quickly absorbed and
"filteredby the pure siliceous sands and gravels, to gush out in
"numberless springs, feeding the brooks which bear the sparkling
"waters to the ponds and reservoirs.  From these flow the large
"streams which by uniting form the Croton river.  This is finally
"expanded by the dam at the head of the aqueduct, into a broad,
"deep lake, the fountain reservoir, or Croton lake, in which the
"quiet waters deposit the finer sediments and thus undergo a final
"purification before they are admitted to the aqueduct.  Nowhere
"along the streams can anything be found which can render the
"waters impure. Rugged rocks or bright green pastures generally
"border them. At certain seasons of the pear, as when the snows
"melt in the spring, and the waters scour the still frozen earth, the
"water is often discolored when it reaches the city, and alarmists
"begin to discuss the danger to be apprehended from the poisons




35


"and miasmata which are derived from the bogs and morasses of
"Westchester County and Putnam County.    But we have never
"been able to trace any sickness whatever to such sources, and do
" not believe that any unwholesome impurities ever occur in our
"water. The purity of the Croton water is remarkable." *
The present aqueduct is now bringing into the city daily all the
water that it can carry with safety, and it is necessary that steps be
taken at once to bring in an additional supply.
The importance of a full supply is too great to be dependent upon
one aqueduct, and another should be built entirely away from and
independent of the present, that in case of accident to one the other
may not be affected by it. It is now impossible to keep the water out
of the present aqueduct sufficient time to make the thorough repairs to
it that it requires. Had we another aqueduct, the water could be
drawn from it for such time as may be necessary to thoroughly repair
it, when it could be made fully as good as when the Croton water
was first brought through it in 1842.
In order to keep the supply necessary for the city until another
aqueduct is built, meters will be required on all places where extra
water is used to stop the waste, and every effort made to stop the
waste in private houses. By such exertions the demand may be kept
down to the present supply until such a time as another aqueduct can
be built. Work on the present aqueduct was commenced in the fall
of I837, and the water brought through it and let into the reservoirs
at Eighty-sixth street, in July, I842.
The present facilities for excavating rock with steam drills will
expedite work, but it will not be safe to expect the completion of the
work and passage of water through it in less than three years after the
work shall be placed under contract.
The quantities of work in the estimate for the new aqueduct are
full and the prices such as the work can be done for.
Very respectfully, your obedient servant,
JOHN C. CAMPBELL,
Chief Engineer.


* From Report of Croton Aqueduct Board, I863.




36


DEPARTMENT OF PUPLIC WORKS,          )
ENGINEER'S OFFICE, CARMEL, PUTNAM COUNTY,
NEW YORK, December 20, I875.
JOHN C. CAMPBELL, Esq., ChiefEngineer:
SIR-I herewith submit a report of operations in the field (together
with profile and estimates) of the engineering parties who have been
engaged in making surveys for a new aqueduct from the Croton to
the Harlem river. The map is not quite completed, but will be sent
to you in a few days.
The first party, under the charge of Mr. Charles L. McAlpine,
began work on the 20th of August, locating the site for a dam across
the Croton river one-quarter of a mile above the head of Croton lake,
and establishing a flow-line for a new lake or settling basin 30 feet
higher than the lip of the present Croton dam. From the point
where the dam was located a line was run down the east bank of the
Croton lake on a descending grade of 0.020 per Ioo feet, or I 56-Ioo
feet per mile, which grade was continued to the end of the line.
Leaving Croton Lake at the mouth of the Kisco river, the line follows
up that stream to the summit between it and the Bronx river, and
down the Bronx to the end of the route. The length of this route to
High Bridge is 36 8-IOO miles, of which 13 98-IOO miles is tunnel, I9
9-0oo miles in open cuts and embankments, and 3 I-IOO miles in castiron pipes to the High bridge over the Harlem river.
The second party, under the charge of Mr. Horace Loomis, began
on the 6th of September, at a point on Mr. McAlpine's line on the
north bank of Kisco river, near its mouth, and crossing that river
continued down Croton lake to a small stream called Trout or Van
Cortland brook, and followed it to the summit or head waters of the
Pocantico river; following down that stream four and a half miles,
and thence across to Sawmill river valley, which was followed for
twelve and a quarter miles, thence crossing the ridge to the valley of
Tibbet's brook. In the valley of Tibbet's brook the line runs about
three miles alongside of the present aqueduct, varying in distance
from fifty to one hundred feet to the east of it, and on ground from
thirty to forty feet higher. From where it leaves the aqueduct the
line runs west of Woodlawn Cemetery and thence on high ground to
its junction with Mr. McAlpine's line. The length of this route from




37


the dam at High bridge is 36 52-100 miles, of which Io 6-o00 miles is
tunnel, 23 45-I00 miles is open cuts and embankments, and 3 I-IOO
miles in pipes.
For the lake above the dam two flow-lines were run, one of them
thirty feet and the other twenty-five feet above the lip of Croton dam.
The area of land covered by the upper flow-line will be 860 acres, and
the capacity is estimated at I, 180,000,000 of gallons. The lower flowline will cover an area of 614 acres, and will contain about 765,000,000
of gallons. The upper flow-line covers the track of the Lake Mahopac
branch of the Harlem Railroad, from one to six feet in depth, for a
distance of 1,300 feet, and the lower flow-line for a distance of 400
feet nearly touches the track, the deepest place being one foot. The
water by the upper flow-line will also cover about four feet above the
lower chord of the railroad bridge across the Croton river, the track
being laid on the upper one.
Two points were examined for receiving reservoirs in the vicinity
of Jerome Park, one containing 65 acres, with a capacity of about
600,000,000 of gallons, the other containing about 60 acres, with a
capacity of about 550,000,000 of gallons.
In making these surveys the country has been carefully.examined,
and lines run through every gap or opening that was found between
the Bronx river and Pocantico river and the Bronx river line, which
runs from the summit along the head waters of Sawmill river to
Unionville, is connected with the Sawmill river line a short distance
below that place. In crossing Sprain Brook, on the Bronx river
route, the estimate is for carrying the water across that valley in castiron pipes. The inside area of the proposed aqueduct is 75 32-100 feet.
Estimates are made on the Bronx river and Sawmill river routes
as being the most direct and presenting the fewest obstacles to the
construction of an aqueduct, and I think the estimates annexed to
this report will fully cover the cost.
I am indebted to Messrs. McAlpine and Loomis, and the young
men under them, for their careful and skillful prosecution of the
surveys, and their promptness and dispatch in making up the
estimates and profiles.
Respectfully submitted,
THOMAS A. EMMETT,
Assistant Engineer in Charge.




38


ESTIMATES ON SAW MILL AND BRONX RIVER PLANS
ACCOMPANYING ABOVE REPORT.
Estimate for Lake and Damn at head of Nezw Aqueduct.
860 acres of land, including buildings................................  $300,oco oo
Clearing and grubbing.........................................     5,000 00
8,500 cubic yards of earth excavation, at 25C............................  2,125 00
24,000      "      rock  excavation, at $1.25...........................  30,co0   o0
2,C00      "      tunnel cutting in rock, at $6.......................  12,000 00
90,000      "      embankment, at 50c............................  45,000 oo
500      "      concrete  masonry, at $6............................   3,0oo  oo
4,500             rubble  masonry, at $5.............................  22,500  00
200      "      brick  masonry, at $12.............................   2,400  00
2,000      "      cut-stone masonry, at $25..........................  50,000  oo
Gate-houses, gates, screens, etc........................................  30,000  oo
Making new road, raising railroad bank, and bridge......................  30,000 oo
$532,025 00
Estimate for New Aqueduct on Saw Mill River route, from Dam to High Bridge 36 52-100
miles, of which 10 o6-1oo miiles is in iFnnel, 23 45-100 miles in Open Ctt, etc., and
3 OI-100 miles by Pipes.


300 acres of land for right of way, at $500............................
Clearing and grubbing.........................................
66o,coo cubic yards of earth excavation, at 30c...........................


I30,coo
254,coo
200,000
75,coo
65,00ooo
41,000
253,400
130,300
6,750


"      rock  excavation, at $1.50..........................
c"     tunnel cutting  in  rock, at $6.......................
"      embankment,  at  3 c..............................
"      foundation  wall, at $2.25.........................
4"     protection   wall,  at $2.25..........................
'  -   concrete  masonry, at $6..........................
"      rubble  masonry, at $6.............................
"      brick  masonry, at $IO.............................
a      hammer-dressed masonry, at $15..................


$150,000 00
5,000 00
198,000 00
195,ooo oo
195,000 00
1,524,000 00
6o,oco oo
I68,750 oo
146,250 oo
246,000 00
1,520,400 00
1,303,000 00
101,250 00


3 miles of new  roads...........................................  30,000  oo
$5,645,650 00
3 OI-Ioo miles of 48-inch pipes (six lines), at $I32 per foot..........  2,097,850 00
Gate-house...................................................  30,000   0
Estimate of dam...............................................  532,025 00
60 acres of land, at $2,000 per acre.................... $120,000 00
350,000 cubic yards of earth excavation, at 25c...............  87,500 oo
105,000      "      rock excavation, at $1.25..............  131,250 00
120,000     o" embankment, at 30c..................       36,000 00
12,000      "      puddle, at $i........................  12,000  00




39


6,000 cubic yards of slope wall, at $2.......................  $12,000  oo
Gate-houses, gates, etc............................   50,000 oo
$448,750 00
$8,754,275 oo
Add for superintendence and contingencies...............................  437,714 oo
$9, 91,989 oo
Estimatefor New Aqueduct on Bronx River Route, from Dam to High Bridge, 36 o8-IOO
miles, of which 13 98-100 miles is in Tunnel, 19 09o00 miles in Open Cuts, etc., and
01-I0 miles by Pipes.


300 acres of land for right of way, at $500...........................
Clearing and grubbing........................................
350,000 cubic yards of earth excavation, at 30c..........................




230,000
360,000
100,000
55,000
50,000
28,000
203,400
113,300
8,ooo


"      rock  excavation, $1.50............................
"      tunnel cutting  in  rock, at $6........................
"      embankment, at 30~.............................
"      foundation  wall, at $2.25.........................
"      protection  wall, at $2.25..........................
" *    concrete masonry, at $6...........................
"      rubble masonry, at $6............................
"      brick masonry, at $  I.............................
"      hammer-dressed masonry, at $I5....................




$150,000 00
5,000 00
105,000 00
345,000 00
2,160,000 00
30,000 oo
123,750 00
112,500 00
i68,ooo 00
1,220,400 00
1,246,300 oo
120,000 00
40,000 00
396,ooo oo
$6,241,950 oo
2,097,850 00oo
30,000 oo
532,025 00


2 gate-houses, etc., at Sprain brook...............................
18,000  lineal feet of 48-inch  pipe, at $22..............................


3 OI-Ioo miles of 48-inch pipes (6 lines), at $132 per foot...................
Gate-house..........................................................
Estimate  of dami.....................................................
Reservoir near Jerome Park.
60 acres of land, at $2,000 per acre..................... $120,000 00
350,000 cubic yards of earth excavation, at 25c...............  87,500 oo
105,000      "      rock excavation, at $I.25..............  131,250 00
I20,000      "      embankment, at 30c..................  36,000 oo
12,000      "      puddle, at $I........................  12,000  oo
6,000      "      slope wall, at $2....................  12,000 oo
Gate-houses, gates, etc....................................  50,000  00


448,750 oo
$9,350,575 oo
Add for superintendence and contingencies..............................  467,529 oo
$9,818, o4 oo




40


EXTRACT FROM REPORT OF THE CROTON AQUEDUCT BOARD, MADE
JANUARY 5, I863, TO THE COMMON COUNCIL.
With an aggregate annual precipitation of rain and snow of 42
inches vertical height, which is about the average for many years
past, the quantity falling upon the Croton basin, tributary to our
works, is equal to an average of 667,674,257 gallons per day.
Judging from experiments made in other localities, the physical
and geological features of which,'while resembling the Croton basin
to some degree, are less favorable as a whole, the loss from evaporation, vegetation, and such absorption as does not subsequently
reappear in springs, may be put down as equal to 14 inches vertical
height of the total annual rain-fall. Make a further deduction equivalent to one-sixth of the entire annual rain-fall, to cover loss by evaporation and filtration from storage reservoirs, and we find that a
quantity equal to an average of 338,832,I28 gallons per day, would
find its way to Croton dam and the inlet of our aqueduct.
Were it necessary to use the entire yield of the Croton basin, a
great portion, if not the whole of this quantity, could, by a proper
system of storage reservoirs, be saved and made available.




41


Cc B.,
Estimate of Mr. G. W. Birdsall, First Assistant Engineer, for conveying water from termination of surveys of Saw-mill and Bronx
river routes, north side of High Bridge, to Central Park Reservoirs.
Estimated Cost of Laying 10-48" Pipe from North End of High Bridge to Connections with
Central Park Reservoirs.


Lineal Feet.
From north end High Bridge, by Sedgwick
and Ogden avenues, to McComb's Dam,
4,800  feet............................  48,000
Across Harlem river to One Hundred and
Fifty-third street, I,500 feet............  15,000
McComb's Dam road and One Hundred and
Fifty-third street, and Eighth avenue to
North Gate-house, Central Park, 5 pipe,
I6,000 feet...........................  80,ooo
Seventh avenue and One Hundred and Fiftythird street to Fifth avenue and One
Hundredth street and North Gate-house,
Central Park, 5 pipe, I8,0oo feet.......  90,0oo
Total lineal feet...................  233,000
82,ooo tons 48" pipe delivered at dock, at 30.......
350 tons specials and branches, at $75....
Stop-cocks, hydrants, etc..................
Hauling and laying 235,000 ft. 48" pipe, at $2.......
60,ooo cubic yards rock excavation, at $2.50.......
235,000    "     earth excavation, at 30 c.
290,000    "(   filling, at Io c.................
80,0oo square yards pavement to relay, at 25 c.......
Extra expense crossing Harlem river6,ooo cubic yards concrete, at $Io......
30,000    "     excavation, at $5...........
Contingencies........................
Add 10 per cent for engineering and
contingencies.......................


i
i....................  I


$2,460,000 00
26,250 00
71,000 co
470,000 oo
150,000 00
70,500 00oo
29,000 oo
20,000 00
60,000 oo00
150,000 00
40,000 00


I #42A67eno 00nn


~0 J. 1-r- ' j  --..........  354,675  oo..........    $3,90,425  00..




*


TABLE 1.
SHOWING WASTE OF WATER OVER CROTON DAM.


0
MLIONTHS.    X u
Uc
January........ I0.45
February....... 2.18
March......... II.79
April........... 1 50
May............  9. 16
June........... 1.29
July.........    3.66
August......... 5.65
September....... 80
October....... 3.27
November...... 8.03
December....... 9.90
Average daily waste)
in U. S. gallons per
year.............


1863.
I  Average
Daily
Waste
IPer Month.
Gallons.


492,889,805
577,015,622
593,52I,536
522,240,3 5
397,367,737
23,549,244
130,131,046
195,376,905
38,813,937
124,938,305
322,179,348


0r
k-g
Vt
aQ5
2.
4-47
7. I
7.70
8.84
2.92
i.6 -2.00
4.7I
8.87


I864.
Average
Daily
Waste
Per Month.
Gallons.
401,909,383
I48,840,523
260,810,911
293,170,821
354,266,997
84,015,412
50,596,702
50,574,082
144,042,562
359-55I,272


1865.                 1866.                 1867.....
o.1.                         Average      0.
U       A       e             Average   AverageAverage
Daily                 c         Daily      L          Daily     OU r
Waste                 Waste                 Waste
Per Month       ~      Per Month.     o      Per Month.     ~.gE       Gallons.                          a,  Gallons.  Gallons.
10.20   444,492,829    5-50    180,493,695   4-39   I29,o86,655   7.96
5.75   218,3I9,6801 i6.80,119,330,543  14-73   773,323,600o   365
I4.81   790,830,624    9-77    406,809,297  12.oo   551322,898   1i370
8.97   358,022,600   1O.03    420,795,777   9.93   4i7,567,753  I6.33
I.65   562,581,688    9 97    390,692,555  13 48   670,816,408  17 87
7.60   278,039,658    9.7~    402,344,929 1I4-60   7S5,4T3,290  12.26
2.74    80,784,000    2.96     90,730,852  6.941 256,829,196     4.24
7.I31 279,56,724      3-97    139,504,2I2  13.40   700,459,214   7-30
0.12:     I,348,r58   3-T3 1   69,831,484   9-33   417,856,399  16.73
0.15      2,998,362   2.59    I44,919,622   7.55   290,193,855  10.90
5.62   189,968,266   12.20    591,II5,654  9.27    359,947,474  I3.96
8.35   355,31o,l65  1o.96     499,294,183  7.71    298,024,947   3-85.....   296,850,229.....   379,655,150   *.      470,903,474....
i                          _     _  _      _      _     _  _


I868.                I869.
o.
Average    |         Average
Daily     |   U      Daily
Waste                Waste
Per Month.           Per Month.
Gallons.       E     Gallons.
299,8I3,000   8.67   343,350,000
87,636,000o..........
675,234,000o  6.48   847,972:500
867,997,coo  12.26   568,492,500
995,175,000  10.51   461,325,000
567,487,000   5.4I   170,25-,ooo
I 6,122,000   1.48    24,337,500
261,12, 000.... i.........
908,37,000...............
476,797,ooo   9-45   387,750,000
693,150,000   8.TO   300,000,000
104,250,000  II. 9  496,875,000
504,424000....    327,300,000


4P
tI,,


i


427,651,960 o 8.o6
32,47,98
IalIg9 -

316,223.620


205,333,524




TABLE I-(Continued).
SHOWING WASTE OF WATER OVER CROTON DAM.
1870.                    1871.                    1872.                    I873.                   1874.                    1875.
o                                                 0.                       0                                                o.
MONTHS.,: AAverag                 Average                                  X Average   Av e                              Average     A   ra
r.                     U
Daily                         Da ly          =                                                          Daily         _ =  Daily  Da
Wase                      Waste         e          Waste         -c        Waste                    Waste                    Waste
0        Per Month..      Per Month.        *     Per Month.               Per Month.      ~        Per Month..     Per Month.
Gallons.        c E       Gallons.      -2 E       Gallons.      r E       Gallons.                 Gallons.                 Gallons.
January......    3.51     657,000,000     1.16      22,25,000      775      285,300,000    I3.34     639,322,500    1378     675,600,000     o.88       11,077,500
February.....   14.31     712,950,000     7.47     271,875,000     4.76     137,370,000    7.56      272,250,000  1o.68      465,ooo,000    11.83     533,925,000
March.....     12.19     557,550,000    12.40     585,000,000     550      170 872,500    12.09     550,950,000   10.76     472,500,000   1o.Io      419,250,000
April.........  14.64     739,050,000     8.20     307,500,000    11.36     5 7,500,000   20.50     I,22),820,000  12.45     585,000,000    16.45     888,ooo,ooo
May..........    7.14     255,000,003     7.85     292,500,000     4.96     147,750,000   20.88    1,375,000,030    10.84    478,500,000     6.80     231,525,000
June..........  2.83      60,600,coo     5.57     172,5000000     4-94     I47,375,coo     0.72       8,550,000     3.41      82,500,000    0.70       8,550,000
July......       0.82       9,000,030     2.42      51,750,000     i.16 o    20,775,00...............      3.o8      69,000,000    0.40       4,125,000
August........   0.8        9,000,000     2.49      52,350,000     5.25     159,375,o0o     1.36      2r,ooo, o-o.99     37,425,000    15.07     771,750,000
September..................          1.76      30,825,000     4.86     142,500,000    0,35        3,150,00     0.55,725,000     2.93      67,500,ooo
October......   o. ro8       750,000      7.31     234,000,000     4-4~      26,0C0,000    4.44    1 20,00,000      I.99      37,425,00      0.23,650,000
November....     2.04      37,500,000     3.53     657,750,0o0  i 9.92     4[7,750,0c      5.78      206,250,000    1.23      20,250,000     8.05     300,000,000
December....    2.04      37,500,000     8.58     330,000,000     5.93     187,500,000o.53     516,750,0:0     3.05     68,850,000     6.90     240,000,000
_ _     _   _    _ _  j       _, _______ _.            - -          -
Average daily waste) ji
in U. S. gallons        256,325,00.... 250,680,00...       205,005,000....      403,582,000.....    249,750,000..     289,777,000
per year.......




TABLE I-(Continued).
SHOWING WASTE OF WATER OVER CROTON DAM.
1876.                    1877.                     1878.                    1879.                    1880.                     1881.
o                                                                                     Aea
MONTHS.         f        Average       So Average                                                       eraAverage  Av        Average                  Aver
Daily                              Daily                                 Daily Daily              Daily Daily
Waste                             Waste                    WasWasWae                                          Waste          c         Waste
Per Month..     Per Month.      ~ g      Per Month.                Per Month       ~        Per Month.      ~        Per Month.
-s        Ga.                  Gallons.    Gallons.                             G allons.                 Gallons.         E       Gallons.
I I  G a l l o n s.                                                                    __                       __
a79ioooo               2 40                                                                                                       -     30,85000
January......    5-74     179,oo10,0      2.40       51,750,o00    9-50     387,967,500      5.54     171,cOO,o0      9.90     418,500,ooo     1.80       30,850,coo
February.....   I2.62      593,250,000     6.Ii      199,20D,000 T 3.11      628,000  000    9.40      382,500,000    11.04     483,750,000    11.97      547,500,000
March.......    18.34   1,035,000,000     19.65    1,155,900,000  13.08      620,925,000    13-74     675,000,000     10.79     472,500,000    17-58      973,175,000
April......... 1756       975,000,000    10.71     472,500,000    6.70      232,320,000    i6. 6     862,500,000      8.io     300,750,000     7.03      245,320,000
May.........    7.50      272,175,000     2.77      6i,350,000    5.99      194,700,000     740      268,500,000      2.89      67,500,000     5. 4      149,000,000
June.........    1.63      25,500,00      1.00oo      3,245,000    553      171,000,000     2.80       60,000,000     0.21       1,650,000     6.16      199,400,000
July..........   017           900,000oo...............   37 -,6 50,o  0     1.40      22,50O,OOO     0.30 22,00,000           0.48        4,925,coo
August.................................  1.39  22,875,000  4.00  105,975,000...............................
September..........................    6.8    1  245,250,000       93      105,000,000...........................
October.....     2.50      52,372,500    2.47       52,350,000     1.51      24,375,000....................
November.....8o       30,825,000    13.68     672,225,000     6.87     246,000,000     2.60      54,000,000     0.63        6,0oo,ooo     0.13         918,c00
December....     0.03          187,500     7.05     245,400,000   20 03    1,185,135,000     7.54     272,250,000     0.23        1,687,500     5.97      194,500,000
Average daily waste)
in  U. S. gallons        259,327,000.....     243,66i,000....     334,140,000..     25,300,000                146,233,000.....       9,465,600
per year..........)
NOTE.-As the flow over a dam does not vary directly as the depth of water on it, and the averages being made from single daily measurements, the above table is not
absolutely accurate, but as close an approximation as is required.




TABLE 2.
AVERAGE DEPTH IN AQUEDUCT AND AVERAGE DELIVERY IN GALLONS PER DAY.


_ _ _                                                                                         I                    I


I868.


1869.


I870.


1871.


1872.


I873.


1874.


MONTHS.


2
-o
0.2.b1
sc2
P. 4.j
Qr
>1
a)


w t
2
= 02;.E.
5) 5d
P"


2
'0~
2
v:j
-
0
Q)
a)
P


2
41)
z
a)b
a, C~
EE
P,


January.........
February.......
March..........
April............
May...........
June............
July.............
August.........
September....
October.........
November......
December....


Feet.....
5-76
6.oo....


Gallons...............................
77,950,000
82,189,000..........


Feet.    Gallons.
I..............
6.02    82,500,000
6.02    82,500,000
6.oo    82, 89,ooo
4.96    64,700,000
3-50    47,937,00o
6.13    84,900,ooo
6.oo    82,189,00o
6.37    88, co,ooo


Feet. I
6.28
6.21
6.o8
5.62
5.96
6.ox
6.00
5.62
5.03
5.83
5.75
5-77


10
a,
Gallons.
87,000,000
85,50o,ooo
83,565,000
75,775,000
81,300,000
82,190,000
82,189,000
76,000,000
65,000,000
79,382,000
77,960,000
78,000,000


5 M
cn
Q I
Feet.
5.84
6.oo
5.90
5-95
6. o
6.02
6.15
6.05
6.oo
6.03
5.88
6.13


Gallon-.   Feet.    Gall ons.
82,i89,ooo  6.45    89,0~~,ooo
2)     I             a) I
80,797,000  6.39       0,,Q                 i Qa
82,89,ooo  6.52    90,07%o05
Gallons.   Feet.    Gallons.
7982,o,000  6.32,22540,000
82,189,000  6.45    88,000,000
80,797,000o  6.39   88,500,0o 0
81,300,000  6.60 i 91,290000
82,89,000oo  6.52   90,079,000
82,200,000  6.20    86,220,000
84,9I7,000  6.36    88,ooo,ooo
83,000,000  6.19    85,500,00D
82,189,000  6.38    88,500,0ooo
83,000,000  6.19    86,220,000
80,000,003  6.17    84,917,000
84,917,000  6.17    84,917,000


7.23    99,545, 0
7.02    96,834,000
6.75
6.8209 97,71377,000
6.25    99,58o,ooo
6  75 I  93,612,000
6.80    93,682,00ooo
7 -04   97,000,000ooo
7.36   10o,741,00ooo
7.66   102,838,ooo
|7 *66 i r02,838,oso


12
I.2
cn
U.U
^ tb
a.n
Q (I
Feet.
6.8i
7.09
7.12
7.o0
6.85
7.0o
7.I7
7.28
7.41
7-37
7-33


'0
u
o ~.'
-
a
Gallons.     4
94,448,000    Cs
97,777,000
98,177,000
96,954,000
95,000,000
96,954,ooc
98,695,oco
98,395,000
100,000,000
io,o8o,ooo
100,94I,0oo
100,341,000


I                             I


I


I


-






TABLE 2 —(Continued).
AVERAGE DEPTH IN AQUEDUCT AND AVERAGE DELIVERY IN GAILONS PER DAY.


1875.
MONTHS.                    a
cbs
NO.  _
a.
Feet.    Gallons.
January......... 7.38     100,780,000
February........ 7.45     101,350,000
March.......... 751      101,89,0ooo
April............ 7-49     oi,6oo,oco
May...........   7.48     1o0,500oo,o
June..             7.50   101,746,000
July............ 7.48    101,500,000
August......... 7.57     102,320,000
September.....    7-58 1 12,338,oo0
October.........   60    102,458,000
November......     756   102,200,000
December...... 758        102,338,000


-—  --- —--


a
Q
Feet.
7.52
7.53
7.62
7.60
7.58
7-49
6.98
5-50
5-44
6.55
6.5~


1876.
P       Q
o        ~
Gallons.   Feet.
11o,866,ooo  7.09
101,926,000  7 35
102,518,000  7-35
102,578,000  7-43
102,458,000  7 45
102,338,000  7.32
1o1,686,ooo  7.12
96,784,000  6.8i
73,617,00o  5.-0
72,743,00ooo0  6.26
90,679,000  7.30
90,079,000  7.26


I877.
'3
t
>
Q.,
Gallons.
97,877,000
100,541,000
100,541,000
101,280,000
101,480,000
100,241,000
98,177,000
94,528,000
64,81 0,000
87,646,000
100,041,000
99,651,000


1878.                1879.               I880.
~bf                   boa                  o e C c
tI.                  _   -            -
Feet.    Gallons.    Feet.   Gallons.    Feet.    Gallons.
7.28    99,85I,000      7.33  100,341,oo000  i 734  Ico,441,ooo
7.26    99,65  ooo   732   00,24I,000   733    1o,341,oo
7.27    99,751,ooo  7-36    1o00,641,000oo  7 - 35  1oo,54,ooo00
7-27    9975,ooO    7-35    I00,54,000   7-35   100,541,000
7.2I    99,5o,ooo000  7.3I 100,141,000   7-32   1oo,24T,coo
7.30    C0o,041,000  7-3I   10oo,4,0oco  7.25    99,55I,ooo
7.29    99,94,ooo| 7-32 |100,24I,000     707     97,677,oco
7.27    99,75I,0ooo0  7.28   99,851,000  7.I7    98,695,oo0
7.30   100, 04,o00   7.02    97,oo4,oco  7I9      8   5oo
7.32   100,241,0C00  7-36   100,641,000  7.-12   98,I77,ooo
7-33    00,341,000oo  7-36  100,641,000  7.23   1 00,T41,000o
7.34   I,440,coo     7.34   10oo0,441,coo  7.09  97,677,coo
-f~i~j




I88I.
Feet.     Gallons.
2       04
7.- 31  97,9477,000oo
7.29    99,851,00ooo
7. 9    99,95441,o00
7.29   99,95xooo
7. 29   99,957,000
78,,
7.34   10,4,0
7.3 10,4,0
7.32j   10,4,3


-p
C)\








TABLE 3.
RAIN-FALL IN CROTON BASIN.






1866.
II          I


MONTHS.
Tanuary......
February.....
March.......
April.........
May..........
June.........
July..........
August.......
September....
October......
November....


E


0
U
1.04
5.58
2.15
2.69
5.o6
4.41
4.27
5.50
6.i6
4.44
3.87




a)
0
U
_   i
3.33
3.60
3.33
3-79
5.62 1
4.45
4.01
6.56
4.92
5.09
3.80o
3.27
51.77  i


V2
U)
C
o
14
o:....................................


E
cs
2
U
o
1.26
4.90
2.46
3.I3
7.26
7.19
5.22
8.79
3.66
4-74
3.42


6.867. 3.7         868.
2.~
5.28....   I.23  2.90
3>7!      547   3.87
5.25...     3.65  2. I3....
0O.04.... I 13-05  6.98
3.62       20.47  933
3.66....   o63  o 87....
3.I0....   7-I4 4-65....
2.....50 2 1.35....
50.77.. 82.461 50-33 *...


I869.
UU
540    379....   5
5-40   3-79 '....- 9-5I
5.75   3.64     6.37
9.5i   5.48....  7.23
3.38 1 2.II        4-95
6.72   4.52        2.71
1.19  3-59...
2.06   2.26..    2.75
1.97  1.92      i 7.71
2.64   3-20...     2.36
8.93  9-46       7.62
7.23   2.43  * —   3-74
5.74   596...   1.20


I


1870.            1871.           1872.
I                     I     I!


I873 -

<u
c
22)  I
5.45  1
6.40....
5 -45
5.10
2.85
4.73
2.51


U           C
0           2
2     0     0.8    3.80.....12  3.8....
5.62  4.27
4.92  3.o-0..
5.74  3-45  * ---
8.62  5-73  *-.
5.33  5-07. —.
9.48  5.24
1.47 1. 44  *
7.89  6.18 1.
7-71. 4-35 i- -


U.76
i 29
3.57
~70
3-93
3.65
3.17
5I.9
7.83
I.8o
4.51


U
2,59
'  W4
3 04
3 69
-00
~4- I 34
5-99
3 69
2.2...
2.59:...
3-04  ----
3.69...
4.00 74....
4-34 * ---
5-99. *
3.69....
4 4.9 1; *
3.68 {....
40.74! * —


2.14
U
2.96.40
I.90
3.I7
3.02.14
4-44
9.91
5.36
4.85
2.16
2.37
46.08


2.;1
U.
5.66
3.09
4~
3.08....
3-77.
2.91.71....
2.21....
5-73....
3.72....
5.13....
3 -73.8  -
5-I3....
3 -72.
4.13
43.87


December.... 3.59....  1.98


I


'  1.40.....42   2.59.... I.8o


48.78


Totals....


54.3.... j 54-03


60.52 48.36.... 56.15 44-63....






1748.. 448 -72.8I  48.94 |.... *  - 43.48


I                         I


I                                                                   i                           I                                I                                                            I










TABLE 3-(Continued).
RAIN-FALL IN CROTON BASIN,


I


I


I


I


877.
L0
o   a



1878.             I879.             i880.             i88i.
i   ~             C).  I  ~.     )
I:3.65...
d
3.0                                4.5  4.29.76 6.4 6.
4-97 I-72 |.I                       I7.    2.,74  3-   3
449....4.56    2.52 j 2.20  3.71  4.00  3.69  5.32  4.19  5.06
3.65....  4.53  2.85  2 2.47  2.85  2.92  3.13  6.70  5.28  4.65
3.io0....5.76    4.96  385   3.30 1 4.51  4.21  9.76  6.14  6.i6
2.85.... 417    5.10  4.0o 3.28   399     44.86  1.67  1.20
4.97  1.72  2.19  2.45  2.02  I.I 1.17    I1.00  2.74  3.74  3.89
4.65  6.I3  5.23  5.29 J 5-36  1.47  1.28  2.43  5.27  5.27  4.62
4.28  3.025.28    5.95  6.12  6.56  565   5 49  i.6o  2.45  2.I7
2.66  4.49 5939   5.83  6.69  5.25  3.63  4.05  2.97  1.71  3.30
6.6I  8.58  2.88  3.43  3.40  2.64  2.69  2.16  0.41  0.75  0.94
3.78  3.5I  0.39  0.95. 57  2.43  3.25  2.5;^ 1.98  3.65  2.75
4.36  4.43  2.59  2.49  2.54  2.54 | 2.97  i.85  5.60  4-50  5.53
8.74  7.08  4.80  4.26  3.17  2.38  2.49  2.44  7.56  6.37  8.12
54.14.-   5177 46.08 43-19 37-51 38.52 35.45 50.77 46.17 48.39






TABLE 4.
Showing Rain-fall and MAelted Snow, in Inches, for each Month in the Years 1862 to 1870, inclusive, at Receiving Reservoir, High Bridge, Fordham,
iarrytown, Sing Sing, Croton Dam, and Boyd's Corners.


I862.


1863.


MONTHS.. _
Q)
p4


January..................
February................
March................
April.....................
May.....................
June.....................
July......................
August...................
September................
October.................
November................
December................
Total.........


3-77
2-33
4.46
1.59
2.85
5-75
4-32
2.45
3-75
4.23
4.75
1.28
41.53
3.46..
3-3.... 4.45.... 3.25. 4.60....-.28.... 3.36
3.I9.... 83.. 2.59.. 5.24
4.55
2..57.... 43.82


>1
H


tu
C/)
be
te;n


0
0
0
o


v(
0
U
-,it.3
> u
P)
P4


I          I
o;:


4.88
2.91
3.25
1.82
2.28
5.65
6.13
1.76
1.73
3.42
4.69
0.57............
2. 33
3.04
4.94


g.0
t
I!.0
cn
cr,._


4.75
2.88
2.17
0.55
5.42
2.18
2.17
3.37
5.98


3.23
3.6I
4.46
4.72
4.58
1.68
6.18
4.91
1.03
3.12
1.76
3.58
42.86


6 I
4.41
5.74
5.77
3.91
5.32
3.29
6.25
2.40
0.82
3.48
3.55


i


o;
0
U      P;
5.25...
O.IO....
3.I6....
4.31....
3.99....
0.52....
10.27....
4.78...
1.39....
4.99
4.37   *4.10 I.
47.23


i.83
0.95
2.03
2.24
4-52
4.59
1.85
2.42
5.09
2-47
3.88
2.83


$4
b._
v,,
*Iu
Q)
P4


2;
be
1.
be)


I864.
-
bb
2.06  I 59   3.o0..o0  1.26   1.95
2.65  2.35  4.50
3.89  3.I6   7.49
5.17  4.54 0I.59
3.o8  2.4 1  5.07
2.20 1 2.61  4.61
5.98  7.88  11.81
5.19 1 4-49  6.86
2.70  2.69   5.72
4.82  4.00   8.95
3.05  3.09   2.90
41.79 39.8o 73.46


1.84.....
I.49
5-49
3.04....
4.95....
I.76....
2.42....
7.45....
3.66....
2.97
3.48
2.73....
41.28....
7.45
3.66
2.97
3.48
4.28   ~~


-P
~D....  0.98,........  4.89! 5.29  6.65


39.09 1.... 30.45


49.83....


34.70....


Mean...............


3      3  6.... 3.65  3.26  54


|....  4.15....  I....


3-94  -....  2.89 |....  3-48  332   6.12   3-44!....


Men                     4.539.. 28...8 33.2 34




TABLE 4-(Contnued).
Showing Rain-fail and Melted Snow, in Inches, for each Month in the Years 1862 to 1870, inclusive, at Receiving Reservoir, High Bridge, iordha,n,
Tarrytown, Sing Sing, Croton Dam, and Boyd's Corners.


----




l


MONTHS.
January......
February.
M arch...................
April....................
May.....................
June......................
May.
June.
July...............
August...........
September...............
October...................
November................
December................


s.
*5
2.66
3-79
4.85
3-77
4.9I
3.72
5-73
3.16
1.77
3.-93
2.69
4.16


1865.
bO
a                  bb
E       0.  3.60  3.19   4-47....  4.54  3.24   3.8I..  583  4.03   8.03....  3-8I  2.94   4.25
**     5-51  6-37  13.88.  4.88  6.60   6.05
5.. 80  8.64 i 6.18.  2.55  3.30~  5-31.... 85  2.7I   3-34.  4.85  3.63! 8.35..  4 I4  3 48  6.30
4.95    3.76   5.20....  52.31 51.29 84.07


I
cd
0
U
3-43
2.86
5.03
2.95
7.38
3.41
3.05
8.12
2.23
4.56
3.   I
3.87


(^
o..........I
I.... I!
I.... I.....5
a,
I.OI
5.38
2.44
2.66
4.33
2.68
4.I3
5.48
3.69
5.41
3.16


a       a. i.... 409....   3.21....   4.36
d O....  6.03...   I459....   5.67....   2.847
i 3-25
* ---   4~09....   3.21....   4-36....   6.03
*-     4- 59....   5. I6....   2.87


i866.


1867.


b4
cI
1.33  o.85
4.48  7.22
2.10  2.60
2.68  2.48
4.57  9.I2
3.39  7.78
3.63 7.87
6:72  8.42
6.23  9.22
5.7I1 5.60
3.08  6.75
3-38  7.79
47-30 75.70


a     0
(     U
2 o
U     C
1.04  3-33
5.58  3.60
2.15  3-33
2.69  3-79
5.o6  5.62
4-4I  4-45
4.27  4.01
5.50  6.56
6.i8  4.92
4.44  5.09
3.87  3.80
3.59  3.27
48.78 51.77
4-07  4-31


2.51
5.78
9.45
4.50
8.54
077
3-73
2.34
5.24
2.50
5.78
9-45
4-50
8-54
0.77
3-73
1.98
2-34.53
2.15
3.5
9.21
4.90
9.14
0.65
4-77
2.45
2.27


--


0,C
>0
1.32
5.87
3.63
2.96
6.34
9.24
4.34
I.04
o.66
5.87
2.59
2.43


0
0.89
4.12
2.20
2.91
6.15
6.09
4.48
8.81
0.24
4.84
2.74
2.26


bX
-E
0.20
8.34
2.40
6.68
9.85
20.15
5.14
i5.i8
1.59
8.64
6.53
3.32


o
a     O
0
33 I ~
1.26  2.II
4.92  3.00
2.46  1.49
3. 13  3-74
7.26  6.86
7.19  5.28
5.22  5.25
8.79 10.04
3.66  3.62
4.74  3.95
3.42  3.IO
1.98  1.62


(n
0


3.04 1.... 4-04


Total.......... 45.14
Mean..............    3.76


-     I
I     _,.
50.04.... I 43.41....  47.31
4.17  I.. -   3.62....  3-94
I I


53.32 47.08 56.29 45-73....  4-36  4-32   7.06
I        I


3-93  6-.3


4.44 1 3.92  4.69  3,81


88.02  54.03:5007
7.35   4-50  4t17
7-35




- - --




TABLE 4-(Continued).
Showing Rain-fall and Melted Snow, in Inches, for each Month in the Years 1862 to I870, inclusive, at Receiving Reservoir, High Bridge, Fordhanm,
Tarrytown, Sing Sing, Croton Dam, and Boyd's Corners.


x868.


MONTHS.           I  "     g
I' b      be  1  L
January.................. 4.53     5.57  4.03
February................. 2.32 ~ 0.36    2.91
March.................... 035      0.75  4-34
April................... 6.09      5.29  6.92
May..................... 6.14     10.4I  3.30
June................... 4.80  4.95  6.6o
July...................... 5.58  7.22  6.39
August................... 8.65     4.86  4.5I
September................ 930      9.09  9.76
October.................. 1.32     1.37  2.38
November.............       428 4.   90   5.32
December.................  2.77    2.56  3.26
Total.............. 56.13    57.33  59.72
Mean.............. 4.68     4.78   4.98


l l


i     b
2.8
5.20.72
I.io j 2.65
2.09   1.67
4.06 1 8.24
7.99  12.26
5.o6  8.86
5-94  4.95
5.86  I4.70
10. 19 21.97
0.72  o.i6
4.30  7.60


d
o
r.
O
3.23
1.52
3.9I
5-47
13.78
7.II
3.65
13.05
20.47
0.63
7.14


> b   0
0    b. b0..0
c(
0    2
2.90  2.99  3.47
I. 38  5. 84  5 75
2.55  4.38  4.01
3.87  I.87  I.39
8.79  4-39  4-14
4.53  4-38  637
2.13  3.83  3.82
6.98  2.49  5-3I
9-33  2.46  3.57
0.87  7-03  7.65
4.65  3.28  3.55
2.35  5.47  5.47
50.33 48.41 54.50
4.I9  40-4  4 4-54


I869.


E
ZC4
3.68
7.50
6.33. 85
4.I4
6.37
3.28
3.13
3.oo
8.45
3.53




bp
0
b      I  Oi
H   i'    1U
4.74   3-95  5.40
4.83   3.80i 575
5.o6  10.64  9.5I
I.96   2.72  3.38
4.38   7.64  6.72
2.74 1 4.62  1.9
2.66   3.82  2.06
3.02   4-55  I.97
2.70   5.61  2.64
7.84  16.98  8.93
2.70  10.03  7.23
7.77 1 8.62  5.74
50.40 82.98 60.52
4.20  6.925 5.04


bI
14.52  2.06  2.II { 2.o5
0    2.66  2.5 2.   7
2.2  6 3.53. 3.33
3.20
2.43 64  5.  2.90  3.75
5.96  2.0649  2.311  2. 05
3.59  2.66  2.50  2.07
93.4679 4.890 4.85 6.619
2.643  2.751  2.96  2.8475
5.96  2.0649  2.11  2.1105
48.36 42.33 39.87 44.89
4.03  3.53  332   3 374


1870.


2.64 '8.9   7.23
4.80   6.40 4.95
3.-9   6.00  2.7
2.77   7.05 i * —
2.98   4.I6  2.75
6.83   7.691 7.-7
1.i6  2.76 1 2.36
6. 8   6.95 i 7.62
2.55   4.04 1 3 74
1.96  I.33  I.20


4. 5
6.40
3.8o
5-45
2.30
2.o6
3-43
5.10
2.85
4-73
2.51
1.49


(I_


2.68


4.64 | 2.50


5.10


55.19 93-42 82.46


56.36


44-87 75.70 > 56.5 44.63


4.59  7.79  6.88


4.69


3.74  6.3  468
3-74| 6-3I i 4-68


3.72


-- -




TABLE 5.
COMPARISON OF RAIN-FALL AT DIFFERENT PLACES.


I  ITI  I          I    I


i866.    1 867. I i868.   I86o. I 187o.


I                  I             I                               I


Croton Dam......
Boyd's Corers....
Southeast........
Sing Sing.........
Tarrytown.......
Kingsbridge......
West Point.......
Central Park Observatory.....
Central Park Receiving Res....


48.78
51.77
75 7~
47-30
47-.3
47.-5
52.23
43.40


54 03
50.77
88.02
45-73
56.29
57.83
54.66
53-32


82.46
50.33
93-42
55. 19
59-72
52.11
64.03
56.13


52
48.36
82.98
50.40
56.36
47.64
45-47
48.4I


I       - -


56.15
44-63
76.54
47-50
45.09
42.33
39.25
42-45


1871.
72.8i
48.94
9.35
60.39
57.90
52.41
5r.26
53-07


I872.
43. 48
40-74
55.60
42.75
48.43
56.38
42.49
47.02


46.08
43-87
66.94
50.44
52.36
44.83
47.99
49.71


1873.  1874.    I875.   1 876.  1877.  1 878.  1 879. I 88o. 1 881.


36.93
42.37
71.87
49.38
*51. I2
47.60
45-83
52.86


53-52
43.66
75~90
59.58
52.44
54-09
40.90
45.31


58.14
40.68
66.24
47-74
43.32
48.x1
41.77
38.91


52.11
46.03
47.76
40.18
42.97


65.90
54-I4
48.78
48.66
49.86


5I-77
46.08
43.19
42.59
39.03
38.66


37.51
38.52
35.45...
33-53
36.64
36.14


50 77
46.17   (Cr
tOj
48.39
46.30
36.26
36.86


--:




TABLE 6.
Showing Rain-fall and Melted Snozv at North Salem Croton Basin, N. Y.; Latitude, 41~ 20'; Longitude, 73~ 38'; Elevation, 36I feet.




YEAR.


I830...........
1831...........,832...........
I833...........
I834...........
1835.........
1838...........
1840...........
1841...........
1842...........
1843...........
1844.........
1845...........
1846..........
1847...........
1848...........
1849...........
I850..........


Inches.
2.18
2.09
3.I8
3-17
3.I7
1.52
6.12
2.45
1.46
6.20
1.55
2.51
2.77
4.94
4-07
3.6i
1.46
1.55
4.46


I'.
Inches.
1.82
2.54
i.6i
1.13
I.I3
0.82
0.82
0.96
1.92
1.70
4.78
3.27
o.88
2.87
2.65
5.41
i.6o
2.09
4.67


Inches.
5-05
2.38
3.40
3-34
1.28
r.77
I 52
2.45
2.51
1.50
5.53
4.44
2.37
3.71
3.76
2.05
5.19
3.68


Inches.
1.76
5.79
2.97
I 57
4.38
6.25
2.04
4.18
4.38
4-95
4-03
1-73
1.62
1.95
1.28
1.23
1 35


Inches.
3.29
3.41
3.58
5.II
4.44
1.46
3.48
3.63
2.54
4-99
2.06
5-49
2.60
6.90
2.05
7.02
5.85


Inches.
5.97
3.3I
1.25
3.89
7.02
1.96
3.48
3.52
2.93
2.77
2.58
2.67
2.05
3-43
3.00
4.4I
1.09
5.41


Inches.
5.50
4.39
3.65
3.01
4-45
5.52
1.79
2.95
1.87
5.56
3.99
6.63
2.36
7.20
5.00
4.27
1.32
6.8I


Inches.
0.4I
3.22
7.99
2.69
0.31
2.07
I *73
3.I9
1.78
6.05
8.74
I.59
3.40
5.11
3.25
1.27
7.24
4.97


-                I
- -         I.0
O)
Inches.
2.25
4.5o
2.25
3.o6
4.75
I 44
5.-4
2.70
2.06
3.80
5.00
1.96
3.84
0.35
5.33
2.o6
1.43
6.63


0
Inches.
4.81
6.51
3.78
9.90
2.15
3.42
3.42
5.82
4.08
4-57
5.80
4-33
4.I7
2.59
3.6i
2.56
7.88
1.64
4.50


4
a)
0
E?1


Inches.
3.4I
3.02
3.6o
1.97
0.83
1.88
3.91
2.81
4.17
2.53
3.9
I.23
5.48
4.78
3.02
2.81
4.42


Inches.
6.92
o.6o
3.67
4.21
I.57
2.78
0.95
3.91
5.56
2.67
1.50
3-57
3.80
2.93
4.88
3.88
3.24


S3
a
a)
P


0  -
O
Inches. Inches.
43.37   3.6i
41.76   3.48
40.93   3.4I
43~5    3.58
33.50   2.60
35.49   2.96
30.87   2.57
38.54   3.21
39.78   3.31
45.72   3.8I
48.91   4.o8
37.49   3-I2
39-50   3.30
45.67   3.80
44.80   3.73
34.62   2.88
42.65   3.55
55.02   4.58
42.41...


DRIEST'
MONTH IN THE
YEAR.


August........ December.
December..... October.
June.......... August.
February...... October.
August........ June.
February...... April.
December..... September.
January....... October..
February...... January.
March......... August.
May.......... August.
February...... July.
April.......... November.
September..... July.
April.......... February.
April.......... May.
June.......... October.
October....... May.
February...... October.


WETTEST
MONTH IN
THE YEAR.


2.73


7.6o


3.03


3.39


I


I




I.  -


Mean......   3.07   2.27    3.11    3.01


4- --    3.63 —08
4.I9  3.46   4.23  13.6  3.6 o8


2.29   3-30




I.


I






August, 1834, Driest Month of this Period................. 0.31 inches.     Average Wettest Month, October......................... 4.50 inches.
October, 1833, Wettest Month of this Period.............. 9.go              Next Wettest Month, July..............................  4.23
Average Annual Rain-fall................................. 4241 The above is taken from page 330 of " N. Y. Meteorology," by F. B. Hough,
Average Driest Month, February, Mean................... 2.27               from Reports of Regents of University.
Next Driest M,tonh November, Mean.................... 2.29      "




54
FROM REPORT OF DR. DANIEL DRAPER, 1876.
THE DROUGHT OF I876.
The most important meteorological phenomenon for the past year
was the drought that caused great scarcity of Croton water in this
city. It began with an unusually small fall of rain, the total amount
for January being.94 inch, while the average for forty-one years is
3.30 inches. There are only two other years on record in which the
rain-fall for that month was less; they are I839, when it was.69 inch,
and 1849, when it was.6I inch.  The following two months were
above their averages, February having 4.8I inches, its average for
forty-one years being 3.40 inches, while in March it was 8.79 inches,
the average being 3.76. After this all the other months were below
their averages, except September, which was I.6o above, as is shown
in Table 7.




55


TABLE 7.
TABLE showing Monthly and Annual Fall of Water for 46 years, in the Vicinity of New York
City (at Fort Columbus, Deaf and Dumb Asylum, and New York Observatory, Central Park).
INCHES.






II                                   I
YJULY.
YEAR.   I JAN. FEB. IMAR. APRIL MAY. JUNE. JULY. AUG. SEPT.
I                    i     I ----/  -   — 1-  -~


1836......0I.o9   2.0o  1.31 i2.66   0.63   6.46   I.44
1837.....2.70    3.70  8.20   7.50  9. 50  8.50   5.90
1838...... 393    3.70  4.10o  2.50  3.99   3.12   1.83
1839.....  0.69  2.05  2.46   3.35  8.37   4.94   1.35
1840.......84  1.84  2.92   2.03  2.39   2.40   i.8o
84.....    5.30    o.8o  235  3.93  3.95   4.65   4.90
1842......07   2.85  1.25   3.60  3.60   3.30   3.80
843......   00 2oo.31 2.3   2.4.00  0.76.64
2 1844...... 2.66    1.03  4.50   0.55  3.41   2.37  6.oo
{ 1845...... 487     3.22   3.33  1.22   175   3.70.75. 1846...... 392 1301   3.82   4.OI   9.70  1.39   6.oi
2 I847...... 4.62    5.74   8.48  1.53 I2.8    6.78   2.62
848.....175 i.68        2.23.16  7.28   4.56   2.64
1849......o.6i    2.26  4.87   0.62   3.47  0.78143
I850...... 5.57  2.64  4.64 2.72    9.20   3.07   3.92
i85i1...... 1.46  4.50  1.70   6.94  4.73   0.90   4.72
I852...... 2.92 i 3.08  4.43   4.74  2.24   2.     3.25
853....    4.4    4.98  203    3.32  5.80   4.80   4.40.i854..... 2.60   4.00  0.70   8.8o   7.70 j2.20   1.90
(i855......  4.77  5.12   2.83  2.86   4.90  5.83   5.06
1856...... 398    0.66  2.08   2.72 I 4.78  3.58   2.79
1857...... 4.99.69  2.32  9.05  6.72  5.43  6.13
858.....   380    3.30  147    4.83  6.oo   6.42   4.32
^   I859.       578   5.59   8.2I  5.10   I.57  4.60   476
~   i86o......2.52    3.28  1.6o   3.21  4.54  21.43  3.33
I 186i...... 4.8      245    5.78  5.62   6.03  4.24   2.89
2 1862...... 5.60  4.17   4.54  2.14   3.84  9.03   5.85
31863...... 5       45  7.04  577  5.69  4.58   1.43  8.6o
864.......2.92       2.04   2.15  3.28   5.23  4.41   3.20
1865...... 340    4.06  832    4.14   5.56  0.42   5.21
{866...... 256    0.09  2.28   4.09  446    438.67
1867......2.54    5.53  4.09   247   5.70 1o.i8    5.76
1i868......4.00    23     3.69  642    7.19  4.66   6.44
869...... 253     6.87  4.61   1.39  4.15   4.40   3.15
870.....  4.4    2.83  333    5.1   1.83   2.82   3.76
2871......2.07    2.72  5.54   3.03  4.04   7.05   5.57
2872.......88  1.29  3.74   2.29  2.68   2.93   7.83
1873.....5.34      3.80   2.09  4.16   3.69  1.28   4.62
I 1874...5.33         2.04   2.22  8.77   2.24  2.78   5.o06
^  1i875......  2 3.7  2.62  3.48  3.o0  2.33  2.72  4.89
1i876......0.94     4.8    879    3.06  303    2.66  3.65
1 i877.....2.62       1.24   556   273    0.95  280    5.73
878......4.46     375   327    1.97 37.19   3.08   4.62
2879......2.63    2.02  3.41   4.33  2.02   3.25   3.58
88......2.02      2.2   4.66   2.90.62 2.14  8.53
88......4.80      4.93  5.8    0.95  3.20   5.35.25


I        I




2.37  3.40
6.30  2.io
4.79  4.96
4-92  3.59
4.25 11.84
2.50  2.90
2.81  2.10
15.26  3.o6
2.73  4-50
3.21  2.62
3.88  0.48
6.93 112.20
1.41  1.87
4.63   2.55
7.2 i 4-712
3.47  1.26
6.20  2.29
5-50  5.49.03   12.90
2.90  I.51
6.73  5.05
3.90  4.26
3-15  3-50
4.12  6.45
3.85  6.24
5.52  4-03
2.15  2.25
4.59  1.05
5.19  5.45
2.23  4.21
4.81  4.85
7.68  0.78
8.31  9.60
2.76  2.82
3.07  2.52
5.6o  2.34
6.29  2.95
9.56  3.24
2.43  8.24
8.97  1.89
2.28  5.28
2.77  1-33
7-97  4-05
7.95  2.37
5.26.85.86.97


ANNUAL
OCT. Nov. DC. AMOUNT.
2.00  1.90  2.30   27.57
2.1I  2.90  6.10   65.5I
3.64  3.I0  2.24   4I290
1.45  2.19  7.61   42.97
4.59  2.90  I.oo   29.80
4.40  3.70  2.70   42.08
4.30  1.8o  3-50   33.98
5.91  2.82  3-34   41-37
4.08  1.73  2.82   36.38
2.50  3-40  2.51   34-08
1.34  8.36  2.99   48.91
2.13  6.29  6.35   64.85
6.61  1.59  4.02   36.80
5.63  1.88  4-OI   32.74
3.i6  2.33  5-36   54-53
2.95  4-53  3-72   40.88
2.06  6.07  4-45   43.84
3.90  6.8o  1.04   52.20
i.8o  3.95  8.6o   45.I8
7.37  3-00  6.86   53.01
i.I8  2.50  4-45   40.50
x.67  1.30  6.42   53.88
4.19  5-99  4-90   51.87.175  3-37  4-42   55-72
3.55  7-.5  4-05   45-17
3.46  8.09  I.73   54.65
6.86  5.631 2.9I   53-97
4.09  3.88  4.86   57-03
2.68  5-I6  5-90   47.61
4.94  4.I9  6.30   62.98
5.28  3.84  3.92   52.23
5.12  2.25  2.56   54.66
2.01  5.I3  4.27   64.03
6.48  2.30  5.02   45-47
4.97  2.42  2.i8   39.25
7.50  3-56  2.24   51.26
3.35  4.08  3-I8   42.49
2.73  4.63  2.96   47-99
1.70  2.30  2.82   45-83
2.85  3-78  2.12   40.90
1.42  3-.3  2.54   41.77
8.14  5.63  0.68 1 40.18
2.43  4-73  5-14 1 48.66.43  2.20  4-94   39-03
2.81  2.46  2.27   36.64
i.6o  2.36  4-.8   36.26




56


This drought has led me to examine the following question:
Has there been in late years any change in the rain-fall of New
York City or its vicinity to affect seriously its water supply?
In a former report I discussed a question nearly related to this,
viz.: "Does the clearing of land increase or diminish the fall of rain."
We found that the wide-spread impression that the clearing of land
diminishes the volume of rain is not based on fact. We shall have
to study the present question in a similar manner, relying on the
observations then used, and others that have since been collected.
As the water supply of New York comes from the Croton river,
we shall have to examine the table of the rain-fall on the shed of that
river, but as the observations for it extend back only a few years, it
becomes necessary to compare them with those of New York City.
The annual observations at Boyd's Corners, which is within the
Croton water-shed, are from    I870 to I877, and    those of this
Observatory are for the same period. By the table it appears that the
rain-fall of these stations varies from year to year, but in the means
for the series there is a variation of only i.8 inch. This might be
expected from topographical and other considerations.
YEARS.    1871.   1872.   1873.   1874.   1875.   1876.  MEAN.
Boyd's Corners...  48.94  40.74  43.87  42.37  43.66   40.68   43.37
Central Park......  51.26  42.49  47.99  4583  40.90   41.77   45.17
The fall at Boyd's Corners resembles that of the city. We may
therefore use our city observations for the missing ones there.
The fall in New York City bears, in like manner, a general
resemblance to that of other adjacent cities, as Washington, Philadelphia, Providence; and since there exist very old observations
made in those places, they may be used in investigating the rain-falls
here. Of course it will be understood that I am not here speaking of
the absolute rain-falls in those places, but the variations they exhibit,
and using those variations as a guide to the determination in New
York.




TABLE 8.
Jlonthly and Annual Fall of Rain, from January, I865, to December, I88I, at Receiving Reservoir, Central Park.


I                                                                                                                                                                                                                                       I


I865.


MONTHS.


0
S:
En
CI).0
S.C.
0
0.8
P4.
0
I),c
t0
P.


i866..0
0      0
0       0
CO
C) 0)
o.0
C     I
M    1 Q
P4      P


1867.


i868.


I869.


1870.


1871.


I    I i
0 -
cO   I
O    I
0    I  U
Uc      C
w    I  o
s' IF;


o
U)
c
in
0 c.a
M


0
C3.0


0
a vI
SO
o
9r


EA
-
C.
0
o
aV


0
r.
i        i
o. c
C'
rt.&
o
C)
c,.
I
$1


0
r3
CO
3 o
c.9
rct
C's


0
0
C0
I


03
CO
C)
Y 0.i9
'd
P4


v
r.
o
C
0
t
0
n
P,


fanuary.....................    2.7
February...............       3-79
March.....................      4.85
April.......................     477
May...............  6.17
June.......................      377
July.........         5.63
August......................     3-6
September..................      2.46
October....................        93
November.................       2.69
December.................        436
49.29


1872.


62     i.oi
8K34   5.28
X  13.34...    2.66..  4-30
2.68....    4-*I3....  48.... 3.69
4.77
3.i6
10      2.71
25'    43-2I


I873.


8K
7K
2........


3.34
5.I5
5.24
2.25
5.78
9-45
4.50
8.54
0.77
3-73
1.98
2.34
53-07


2724
I3
I2%.12
| 2


4.53
2.32
3-35
6.09
6.I4
4.80
5.58
8.65
9.30
1.32
4.28
2.77
59-I
| 59.'I3


253
I524
26
74
8.......
8 82


2.99
6.04
4.98
i.88
4.34
4.33
3.83
2.49
2.46
7-03
3.28
5-47


73 /  4.83   3
II       55   9K
3 i 4-34 1"I
4- 440. 2.o6..
2.78....
3.53   *3-.24.......  2.02..
4.9~ 10.9
2.71.
63    2.49   5
29I   4245   28 —
29    42.45 [ 28,


4. O
4.03
5.74
3.I5
3 -15
4.06
8.05
6.04
6.30
2. 41
8.05
4.6o
2.10
58.63


21     I. 90
8%:. 69....   4.08
2     2. 51.... 3.12....   2.80.... 8.70..  6.6i.... 3.6.... 2.94
4.51
7     4-57
48K    47.04


2K
4
4
4K
243
40o


VUi
0
I
r.
59I
5-91
3.95
2.35
3.87
3.96
1.18
6.oo
7 -84
4.04
3-40
3.4o
4-77
2.38
49.65
3.8


CZ
I
U
c.
CI0
I=
I a
Q
I:-"
12
16
7
|7I


C(n
1<r


21,


83     49.I2


37%










TABLE 8-(Continued).
Monthly ana Annual Fall of Rain, from    yanuary, I865, to December, I88I, at Receiving Reservoir, Central Park.






I874.       I875.
I


1871


o        0      o
MONTHS.         i c               Cl)
O        3      0,
January.........  5.8  64    2.84     2
February.............   3.37    i63     3 3.44   534
March...............    4.09     2      3.15  1172
April...............    9.47....    3.37    T2%
May.................    2.62 j.....    I85
June..................   4.69....    3.2I.
July..................   607....   4.86
August................   2.63....   1.....0
September............1 7. I3.....94.
October..............   1.96....    3.18
November...........      2.13.... ' 4.12
December............    2.89    1 II      2 2.25  3
52.86   3634    45.31    52


8i.o
2.87
0.34
3.93
2.49
rt
2.56
i  3.09
4-3.8
8.0I
3. I8




6.         I87.
0      a
a      3
o      3 7.      0
a    I
3-77
I0     I.79
23    6.43..  2.63.....04
2.73....   5.96....  2.88....    I.22....   8.02
X     5.75
I34    0.75
244    42.97


7.
i
I
' Pc
Qi
= l
o
j o
av
I 18
II




I878.
3.54
4.C
C        O
Q,
354 17
4.04 1 6
3.I7....
1.88....
2.75
4.18.
6.8....
8.oo....
3.52
2.66....
4.51
5.43     2
49.86    84


1879.        I880.        i88i..0 0                30
' a4         C            a
0                          0       _
2.55  I      |5 3.I9   I  4. 4    8
3.85. 4.84         0     4-97    3
6-4.... 2 - 74... 02...
2.09....      o.62....  2.86....
3.I0.   I.O  |     3   -  5.75
2.22 71..       726  |....  1-532.*..
6.50...  4.69.I. 5  05
273          I-34         1-30....
0.35....  3-0.4....  I.83....
2.03   2     2.54   23    2.85 4...
3.77   6     2.7 1  2     4.6I    2 7
38.66  372  36.   I29  |  36.8
38.66  37    36.14  29~   36.86  25


ANNUAL
AMOUNT.




Year.
1865....
I866......
1867......
x868.......
I869.......
I870.......
187I.......
1872......
1873...
I874.......
1875......:876.......
1877.......
1878.......
1879.......


49.29
43.21
53 07
59.I3
49. 2
42.45
58.63
47.04
49 65
52.86
45.3I
38.9T
42.97
49.86
38.66


CJn
00


I
I
i
II
I




x.58
38.9T I


2534


1880....       36.14
I88.......   36.86








TABLE 9.
Rain-jall at West Point, New  York, from  1843 to I88I.


1843.
January.............  2.85
February...........    3.02
March..............5.05
April...............  3 40
May................    2.28
June.................95
July................   3.00
August.............  I  33
September......   3.62
October.............6.95
November..........4. o
December               2. 70
Yearly Rain-fall.. 50.75


1844.1 845. 1846. I847. I848.
5.25   5.15    3-42   4-01   I.87
3.-0   2.88    2.78   6.22   3.98
4.20 1 3. 40      3.90  349  2.71.50   I.80   3.04     ~79   1.90
5.10   4. 10   2.93   2.70   7.15
3-45   1.82.17   2.27   7.37
7.96   2.38   2.46    2.52   4.42
5.28   7.72  10.02    2.20.49
3.50 1 2.60   2.8o    3.58   3.67
4.92   2.93    2.60   1.97   4.33
I.65   5.36   3.65    1.80   6.76
4.12   3-24   4.40    3.50   5.04
49-03  43-38  42.17   35.05  49.69
I43                   3 i


1849.
1.03
2.07
4.55.96
6. io
i. o6
3.15
5.74.42
7.63
2.31
4.11
39.13


I850.
6.o6
3-33
4.84
4-30
8.26
3.97
5.33
5 I3
8.14
2.14
2.17
5.65
59-32


I851. I852. 1853..82   I.62  3.27
5.09   3.80   4.45
2.56   2.68   3.25
7.24   4.66   5.84
4.34   I.65   8.04
1.53   2.30   3-79
4.44   467    9.48
2.58   6.99   7.25
1.22   2.39   3.89
4.02   2.99   2.85
4.3T   2.60   5.60
2.45   0 17 I 2.26
40.60  36.52  59.97


1854.
3.62
5.04
2.81
10.53
5.o8
I. 62
3-73.46
4.00
1.98
5.65
2.64
47.16


I855 1856.
3.63  1.81
4.23.63.83.68
2.52   3-76
4.I6   6.59
4.50   4.81
6.26   2.42
3.10j 11.56.97   4.52
10.25. 1.35
3.69 1 2.50
5. 14  5.76
49.28  47.39


1857.
2.25
I.79
i.88
5.32
5.70
6.38
2.04
3-97
4.46
5-40
2.75
5-55
47 49


1858.
3.83.65.92
4.48
6.17
4.30
3.22
3.52
2.05
3.65
6.30
3.90
42.99


1859.
4.00
2.30
5.85
4.00
2.89
5.49
I.65
6.70
5.20.55
2.70
1.40
43.73


i860..65
4.72.95
4.25
4.90
6.20
5.66
3.80
3.70
5.30
5.35
2.73
48.21


i86i.
4.25
I.8o
3.67
3.75
3.00
2.6o
4.70
3.50
4.05
2.8o
3.90
1.21
39.23


Cn
v10


_


-.






TABLE 9 —(Continued).
Rain-fall at West Point, New York, from I843 to I88I.


January...........
February..........
March..............
April.............
M ay..............
June...............
July...............
August............
September.........
Octok er...........
November..........
December........
Yearly Rain-fall..


i862.
5-47
2.32
2.90
2.6o
2.70
9.60
4.C2
3.00
4-30
4.70
4.56
2.80
48.97


I863.
5-55
2.84
2.65
2.65
5-35
1.90
5.90
3-93
3.65
4-75
4.90
4.85
48.92


1864. 1865.
I.10   3.20
1.75   1.25
3-~00  5.25
6.oo   4-55
4.65   2.25
2.50   4.88
2.80   4-35
5.35   2.65
2.15   3.05
1.35   3-60
3.80   2.70
2.60   3-75
37.05  40.48


i866. 1867..oo00  I.5
4.50   4-40
3.65   1.25
3.20   3.40
4.20  10.50
8.5I   6.oo
2.90   6.I5
5.50  I.75
7.20   6.90
2.10   2.00
3-45   3.50
I.30.83
47- 5  57.83


1868. 1 869.   870.
I.50   2.40   4.90.6o    3.50   6.I5
3.86   4.25   4.65
4.80   3.07   5. 5
IT.66   4.75   3.82
3-45   5 33   3-I5
I.I5   2.43   2.53
7.20   I.90   2.95
II.22   3-35   2.40.90   7.80   3.52
3.85   3.82   I.I.92   4.99   2.00
52.    47.64  42.33


1871.
1.48
2.87
5.24
3-43
3.85
7.27
8.50
6.60
1.03
4.96
4.40
2.78
52.4I


I872. 1873.
i. 70  6.82
I.00   4.80
2.40   2.36
3.20   3.82
5.41   3.31
6.i6.76
2. 0   2.46
10.43   4.4I
5.27   3.34
4-.I   5.75
9.23   2.75
5.38   4.25
56.38  44-83


I874. 1I875- 187(


5. i877.


7.03
2.06
2.08
6.49
2.t5
2.17
8.49
3.10
5.35
2.33
3-33
3.o0
47.60


3.02
4.24
4.22
3-33
I.I3
3.48
4.3I
8.32
I.98
4.18
I4.06
1.82
54.09


I.45
6.48
9.3I
4-38
3-37
3-49
6.40.05
4-47
2.00
3.36
3.35
48. II


3 -37
1.42
7.40
4.00
1.02
5.I5
4.02
2.46
2. I6
9-34
6.o6
1.36
47 76


I878. 1879.
4.I6  2.21
3.15  2.10
3-38  4.29
3.48  6.04
5.37  2.20
3.20  6.25
3-37  2.25
2.35 1 5-30
4.11  3.20
4-46   -35
4.28  3.40
7.47  5.00
48.78 42-59


|i88o. I881.


3.30
3.25
2.25
3.25
I.I3
I.35
5.35
4-05
I.45
2.45
3.30
2.40
33-53


5-45
4.30
5-I5.20
4.40
5.40
2.25
3.oo
2.15
5.30
3.50
6.20
46.30


C)
0


_                                   _   _.                 ~ -.                   _


- ~ ~ ~ ~ ~


-- ------- --- -- ------- ~- - - - -  -. - ---




TABLE 10.
STORAGE DRAWN IN i880 AND i88i, IN MILLION GALLONS.
o..../..  1,  I.. / -~ 50  I 2~  5
3........C'.               -      0.. /"-/.5 I 9060
x88i. i88i.      i88o.  i88o. i88i. i88o.  i88i. iSgo. i88i.  i88o.  i88i.  z88o. r88o.
6o 0...7..  0..5           7 20  50..  90  85  90
2....50 10.....        75.. 30 50 20 90 8    90
3...   50  Io 0..        75     50  50  6o  90  o  90g
4...... 50 30            75......   o  go 908o 70
6......  30....     5..  75  6o  8  go90  8  70
7.-1 ~30 3       ~25 1/"""      175 30 85 90 8o 70
8...... 30  30.35 8.. 75  30  85  90  8o  70
9......   30  30...   65     75  30  85  90  80  70
10......o 30,         7035   5  6o 8 o 1  80  70.    30..... 30         85     75 6   20 go 9075 70
1.    30.....        0 6o 85  75 70 25 90 75 90
o30                      65.....  80  25  90  75  90
14......30               35  /   6o 8..  25  90  75  90
15.....30 6.                  6  go 925 90 75 90
1.......40 /               65  45  90  25  90  75  90
745                       45..  40  90  5  90  70  90
18.........45         15       90o  35  90  70  90..............    45  5. 4 75  90  35  90  70  90
20......              45  25  30  85  90  65  90  70  90.  25
22....45                  30  40..85  90  6  90  70 90..  15
22.So 20 40 85 90 SO 90 70 90.                        25
23...... "/    820 6o  85{90 85 90 7090 go     25
24.........     65  20  60  70  90  85  90  7 90 g  25
25...              65.  50  70 90 So 80  go  75  90  30
26................ 65.. 50  70  8   8  90  75  70.  30
27.............. 65.. 30  50  8o  8o  g90o  70  70  30
28......              75     30  6o  90  85  90  70  70  20  30
29...........75  40 75 90 85 90 70 6o 20 30
30.....     o   40 75 90 85 90 70 6o 20 40
31-...-            50 o" I   9   -   70 20.. 40


Total, i88o.............................................  8,520,000,00o gallons.
Total, i88.................................................  8,6o5,00,000




62
TABLE 11.
Existing Storage-Artificial and Natural.
(From Report of August 12, I879.)
The reservoirs and lakes within the Croton basin, and now
available for storage purposes, are as follows:




-


Boyd's  Corners  Reservoir.........................................
M iddle  Branch  Reservoir..............................................
Lake Mahopac...............................................
L ake  K irk........................................................
Lake  Gleneida...................................................
L ake  G ilead.......................................................
Lake Waccabuc.....................................................
Lake  Tonetta...................................................
Barrett's Pond.......................................................
C hina   Pond......................................................
W hite   Pond........................................................
Pine  Pond.........................................................
Long Pond........................................................
Peach   Pond.......................................................
C ross  Pond.......................................................
Haine's Pond......................................................
Total Gallons............................................


Gallons.
2,727,000,000
4,004,000,000
575,000,000
565,000,oo000
380,ooo,ooo
200,000,000
50,000,000
170,000,000
100,000,000
75,000,000
60,000,000
230,000,000
110,000,000
25,000,000
9,541,oo0,000






63
TABLE 12.
(From Report of August 12, 1879.)
The following table, prepared from daily observations for several
years by the Engineers of the Croton Bureau, shows the rain-fall and
the average daily quantity of water running in the Croton river:


i866...........
1867...........
i868...........
1869...........
1870...........
1871...........
1872...........
1873...........
1874..........
1875...........
1876...........
1877...........
1878...........


RAINFALL AT   I
BOYD'S CORNERSI
RESERVOIR.
Inches.     I
51.77
50.-77
50. 33
48.-36
44.63
48.94
40.74
43.87
42.-37
43.66
40.68
46.03
54.14


AVERAGE DAILY FLOW     PERCENTAGE OF
OF THE CROTON RIVER AT RAIN-FALL RUNNING
CROTON DAM.         IN THE STREAM.
Gallons.            Per cent.
440,705,558             5'.
541,318,397             65.
600,52-4,194            74.
456,575,841             58.
347,935,318      I      47.
357,175,341             45.
307,208,408             49.
444,236,877             67.
4:27,638,306            63.
425,021,738             59.
367,872,936      I      56.
346,503',178            45.
462,854,308             52.




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