1. This Court will not exert its extraordinary power to control
the conduct of one state at the suit of another unless the
threatened invasion of rights is of serious magnitude and
established by clear and convincing evidence. P. 282 U. S.
2. The burden of proof in such cases is much greater than that
generally imposed on a private party seeking to enjoin another. P.
282 U. S.
3. Pursuant to Acts of her legislature, and subject to
limitations fixed by the Secretary of War, Massachusetts proposes
to divert water from streams within her territory, the Ware and
Swift Rivers, which are tributaries of the Connecticut, a navigable
river flowing through Massachusetts and thence through the State of
Connecticut. The diverted water will be conducted out of the
Connecticut River watershed, to the Boston district, where it will
be used for drinking and other domestic purposes. That district
will be faced by a water shortage in the near future, and the
tributaries referred to were selected, after elaborate research, as
the source of new supply, rather than sources in the eastern part
of Massachusetts which are polluted or liable to become so.
Connecticut sought to enjoin the diversion, for herself and as
parens patriae. Held,
upon the facts as found by
a Master and accepted by the Court:
Page 282 U. S. 661
(1) The controversy is not necessarily to be determined by the
common law of riparian rights, which prevails in both states. P.
282 U. S.
(2) Suits of this kind are to be determined on the basis of
equality of right, which means, not that there must be an equal
division of the waters of the stream among the states through which
it flows, but that the principles of right and equity shall be
applied, having regard to the constitutional equality of the
states, and that, upon a consideration of the pertinent laws of the
contending states and all other relevant facts, this Court will
determine what is an equitable apportionment of the use of such
waters. P. 282 U. S.
(3) The facts do not show that any real or substantial injury or
damage will presently result to Connecticut from the proposed
diversions. P. 282 U. S.
(4) The possibility that hydroelectric works in Connecticut,
which, as now existing, will not be affected by the proposed
diversions, might be enlarged in the future so as to use the whole
capacity of the river is not ground for enjoining the diversions.
P. 282 U. S.
(5) The proposed diversions by Massachusetts should not be
enjoined. P. 282 U. S.
(6) Inasmuch as the diversions intended by Massachusetts are
limited to the tributaries in question, Connecticut has no occasion
to ask for an injunction against future diversions from other
tributaries. P. 282 U. S.
(7) Connecticut's bill will be dismissed without prejudice to
her right to maintain a suit against Massachusetts whenever it
shall appear that substantial interests of Connecticut are being
injured through a material increase of the amount of the waters of
the Ware and Swift diverted by or under the authority of
Massachusetts over and above the quantities authorized by the Acts
of the legislature as heretofore limited by the War Department. P.
282 U. S.
Final hearing of an original suit upon exceptions to the report
of the Special Master.
Page 282 U. S. 662
MR. JUSTICE BUTLER delivered the opinion of the Court.
The State of Connecticut brought this suit against the
Commonwealth of Massachusetts to enjoin her from diverting waters
from the watershed of the Connecticut River to provide water for
Boston and neighboring cities and towns.
Legislation of Massachusetts authorizes diversion into the
Wachusett Reservoir of the flood waters of the Ware River, c. 375,
St.1926, and of certain waters of the Swift River, c. 321, St.1927.
The watersheds of these rivers are about midway between the Boston
district and the westerly boundary of the Commonwealth. They are
tributaries of the Chicopee; all are nonnavigable streams wholly
within Massachusetts. The Chicopee empties into the Connecticut
just above Springfield. The latter rises in Canada and northern New
Hampshire. It flows between New Hampshire and Vermont through
Massachusetts and Connecticut into Long Island Sound. It is about
345 miles long, and drains 11,300 square miles, of which 1,385 are
The complaint alleges:
Connecticut and Massachusetts recognize the common law doctrine
that riparian owners have the right to the undiminished flow of the
stream free from contamination or burden upon it. Connecticut
appears as owner of riparian lands and of the bed of the river and
Page 282 U. S. 663
The proposed diversion will take water
tributary to the Connecticut entirely out of its watershed, will
impair navigability of that stream, will take flood waters, and
thereby cause damage to agricultural lands that are subject to
yearly inundation. The Connecticut is now heavily burdened with
offensive matter put into the river in Massachusetts, and requires
all the water that naturally comes down the river to prevent it
from becoming a nuisance and menace to public health. The diversion
will destroy property of Connecticut and of its inhabitants without
due process of law, and cause injury for which there is no adequate
remedy at law. The diversion presently proposed is only a portion
of that covered by the plan adopted by Massachusetts, which
includes the acquisition of the waters of other tributaries of the
By its answer and amendments thereto, Massachusetts denies that
the proposed diversion will cause any injury or damage, and avers
that the amount of water to be taken is negligible when compared
with the flow of the river where it enters Connecticut, that an
emergency exists in Massachusetts constituting a justification for
a reasonable use of such waters, that the serious injury to the
people of the Commonwealth if diversion be prohibited, compared to
the trivial damage possibly caused to Connecticut and its people if
diversion be permitted, should lead a court of equity to give
substitutional relief, rather than that specifically prayed, that
Connecticut's contention that the diversion will interfere with
navigation is not open in the absence of proof that Massachusetts
has diverted or actually proposes to divert more water than is
permitted by the War Department, that the proposed diversion is in
all respects a reasonable use of the waters in question, and that
the project will stabilize the flow of the river and result in
benefit to Connecticut and the lower riparian owners.
Page 282 U. S. 664
By its reply, Connecticut denies Massachusetts' affirmative
allegations and alleged that there is no necessity for the
diversion and that there is an adequate supply of water in the
eastern part of Massachusetts.
The Court appointed Charles W. Bunn of Minnesota as special
master and authorized him to take and report to the Court the
evidence, together with his findings of fact, conclusions of law,
and recommendations for a decree. The master filed his report and
the evidence introduced by the respective parties. It shows that he
heard arguments in their behalf, and sets forth his findings and
conclusions with a recommendation that the bill be dismissed and
that (if it be held that lack of present purpose further to develop
power at King's Island does not warrant denial of injunction on
that ground) the decree contain a provision for the protection of
the owner of the dam and power at that place. Connecticut filed
numerous exceptions. Massachusetts made no objection to the report.
The Court has heard the arguments of counsel and considered their
briefs for and against the exceptions and upon the final submission
of the case.
The report shows that Connecticut sought to prove that any
subtraction from the flow of the Connecticut River through that
state will cause serious damage to the state and its people in that
it will impair the navigability of the stream, lessen productivity
of river bottom lands by diminution of inundation during times of
high water in each year, diminish the power capable of development
at King's Island, diminish the run of shad in the river, and
decrease its capacity to discharge and destroy sewage.
The brief substance of the master's findings of fact
Boston and the surrounding metropolitan area are faced with a
serious water shortage in the near future, and there is need for a
large quantity of additional water. That district includes 35
cities and towns having a population
Page 282 U. S. 665
of 1,900,000. Other nearby cities and towns are likely in the
future to depend on that district for water supply. The total
population concerned is now 2,860,000, and it is estimated that it
will reach 4,572,000 within forty years. There is no serious
dispute about the need of the region to provide presently for
Massachusetts applied to the Secretary of War (Act March 3,
1899, § 10, 30 Stat. 1151) for authority to make the proposed
diversions. After hearing both sides and examining the facts, the
Secretary permitted diversion of the flood waters of the Ware in
excess of 85 million gallons per day between October 15 and June 15
and prohibited the taking of any water except during that period.
He permitted diversion of all waters of the Swift except enough to
maintain a flow therein of 20 million gallons per day; but he
required that, during the period from June 1 to November 30, there
shall be released from the impounding dam 110 cubic feet per second
(71 million gallons per day) whenever the flow of the Connecticut
at Sunderland, Massachusetts (a town 20 miles north of the
confluence of the Chicopee and Connecticut) is 4,650 cubic feet per
second or less, and 70 cubic feet per second (45 million gallons
per day) when the flow is more than 4,650 and less than 4,900 cubic
feet per second. The Secretary found that the discharge at
Sunderland of 4,650 cubic feet per second corresponds to an average
gauge height at Hartford of 2 feet, and that a discharge of 4,900
cubic feet per second corresponds to 2.1 gauge height at
The annual flow of the Connecticut at the
Massachusetts-Connecticut boundary is about 17,000 cubic feet per
second, approximately 11,000 million gallons a day. The watershed
above that boundary is 9,915 square miles. The drainage of the Ware
at the point of diversion on that river is 98 square miles, and
that of the Swift at the point of diversion is 186 square miles.
The diversion permitted
Page 282 U. S. 666
by the Secretary will furnish about 191 million gallons per day.
The Massachusetts Acts do not authorize the diversion of any waters
other than the Ware and Swift, and, as to these, the record shows
that (as far as counsel can commit it) Massachusetts proposes to
abide by the War Department requirements and restrictions.
The total area subject to such diversions is 2.93 percent of the
watershed above Connecticut. The permitted diversions represent an
average yearly subtraction from the flow of the Connecticut at the
state line of about 2 percent, but 94 percent of this occurs when
the Hartford gauge reads above 3.5 feet, which means 11.5 feet
depth of water. The Government has heretofore sought to maintain 10
feet of water below Hartford. A War Department project contemplates
a 12-foot channel. (On that bottom level, 3.5 feet on the gauge
would mean 13.5 feet of water.)
Dredging is required every year to maintain a channel of 10 feet
over numerous bars below Hartford. Navigation is difficult when the
depth falls below 10 feet. There is no difficulty when there is 12
or even 11 feet. The required release of water from the Swift River
reservoir during periods of low water will somewhat benefit
navigation. The maximum diversions are at high water and lessen
depth 5 to 6 inches. At medium stages, the diversion is less, and
at very low stages, the flow is increased. The diversion will not
perceptibly or materially interfere with navigation.
The height of floods will be lessened from one to six inches.
Because of the diversion, small pieces of hay land will fail to
receive flood waters. It is impossible to determine from the
evidence to what extent that will occur. The lessening of spring
floods will have its advantages and disadvantages; it will reduce
some damages and increase others. The damage to the hay land is not
shown to be of serious magnitude, and, far from being
Page 282 U. S. 667
established by clear and convincing evidence, it is not shown by
evidence making it possible of computation or proving that it is
There is shown one possible development of power. It is at
King's Island in Connecticut, where 4,000 horsepower is now
produced. The owner has been authorized by the Federal Power
Commission to build a higher dam to develop approximately 50,000
horse power. It is not shown that the company has determined so to
do, or that the necessary capital has been arranged for. The
present use of the water for power purposes will not be disturbed
the water for power purposes will not be disturbed bu the
diversion. If waterpower shall be developed to the extent of 50,000
horsepower, the diversion will cause an injury of $80,000.
Connecticut failed to establish that the taking of flood waters
will be materially injurious to the shad, run or that the diversion
will perceptibly increase the pollution of the river.
The legislative determination to use the waters of the Ware and
Swift was made, and the Acts of 1926 and 1927 were passed as the
result of long continued and careful study. Connecticut submits two
plans to show that the northeastern part of Massachusetts has
abundant supplies of water for the Boston district.
The first involves combining water from 15 watersheds on the
Assabet, Sudbury, Shawsheen, and Ipswich Rivers. The plan involves
pumping and also treatment of the water for its purification. From
an engineering standpoint, it is inferior to that adopted for the
Ware-Swift development. And, while a considerable amount of water
from these sources may be made available, most of it is of a
quality much inferior to the waters of the Ware and Swift. And the
amount would be inadequate, and constitute only a part of the
needed supply. The operation of the plan would be of uncertain
duration, and might have to be abandoned.
Page 282 U. S. 668
The second plan is based on the taking of water from the
Merrimack. That stream drains a large watershed, mainly in New
Hampshire. It is polluted, and the pollution is practically beyond
the control of Massachusetts. There is no certainty of its
improvement or that it will not become worse. Unquestionably,
polluted water may be made wholesome by proper treatment. A
considerable amount of industrial waste from mills, cellulose
plants, tanneries, rendering works, and gas works, of which there
are many in New Hampshire, is peculiarly difficult to eliminate
from water. The necessary treatment of waters so polluted involves
several processes storage for 30 to 90 days in a large reservoir,
aeration, filtration, chlorination. These introduce a human element
subject to weaknesses and failures of human nature. Instances of
breakdowns are given. There is a small element of danger involved
in every elaborate system of water purification. With a single
exception, all the witnesses expressed preference for a supply of
originally pure water over a purified polluted one. Lawrence is the
only city in Massachusetts using Merrimack water for drinking. It
consumes an extraordinary amount of bottled water, the cost of
which in 1916 was about 55 percent of the amount paid for public
water for all purposes. The plan contemplates the taking of 200
million gallons per day from the Merrimack at Tyng's Island, just
below the New Hampshire line. That is about one-quarter of its
flow. Factories below the proposed takeout would be liable to
suffer damage from the diversion. The stream is navigable below
Haverhill, and it is not certain whether the taking of that amount
would be permitted by the government. The master says:
"I find the taking from the Merrimack ought not to be imposed
upon the Boston District. Because, first, the water is a polluted
water and Massachusetts has no adequate control of the pollution or
adequate remedy to cure it; that the water is of quality
Page 282 U. S. 669
much inferior to the Ware and Swift and the proposed project
inferior from an engineering standpoint to the reservoir and tunnel
which the Ware and Swift development involves."
The Massachusetts legislation confines itself to the taking of
certain waters of the Ware and Swift. The Secretary of War has
imposed additional limitations. Massachusetts declares that she
intends to divert no more water than the Secretary of War permits,
and that she will in every way follow the conditions he
The exceptions filed by Connecticut need not be set forth or
considered in detail. The governing rule is that this Court will
not exert its extraordinary power to control the conduct of one
state at the suit of another unless the threatened invasion of
rights is of serious magnitude and established by clear and
convincing evidence. New York v. New Jersey, 256 U.
, 256 U. S. 309
Missouri v. Illinois, 200 U. S. 496
200 U. S. 521
The burden on Connecticut to sustain the allegations on which it
seeks to prevent Massachusetts from making the proposed diversions
is much greater than that generally required to be borne by one
seeking an injunction in a suit between private parties. North
Dakota v. Minnesota, 263 U. S. 365
263 U. S. 374
There has been brought forward no adequate reason for disturbing
the master's findings of fact. They are amply sustained by the
evidence and are adopted by the Court.
Connecticut suggests that, under the common law in force in both
states, each riparian owner has a vested right in the use of the
flowing waters, and is entitled to have them to flow as they were
wont, unimpaired as to quantity and uncontaminated as to quality.
It maintains that the taking of waters from the Ware and Swift
infringes vested property rights in that state which cannot be
taken without its consent against the will of the owners. And it
insists that this Court, following the law enforced by each of the
states within its own boundaries,
Page 282 U. S. 670
should grant injunction against any diversion from the
watersheds of these rivers.
But the laws in respect of riparian rights that happen to be
effective for the time being in both states do not necessarily
constitute a dependable guide or just basis for the decision of
controversies such as that here presented. The rules of the common
law on that subject do not obtain in all the states of the Union,
and there are variations in their application. The doctrine of
appropriation prevails in some states. And every state is free to
change its laws governing riparian ownership, and to permit the
appropriation of flowing waters for such purposes as it may deem
wise. United States v. Rio Grande Dam & Irrigation
Co., 174 U. S. 690
174 U. S.
For the decision of suits between states, federal, state and
international law are considered and applied by this Court as the
exigencies of the particular case may require. The determination of
the relative rights of contending states in respect of the use of
streams flowing through them does not depend upon the same
considerations, and is not governed by the same rules of law, that
are applied in such states for the solution of similar questions of
private right. Kansas v. Colorado, 185 U.
, 185 U. S. 146
And, while the municipal law relating to like questions between
individuals is to be taken into account, it is not to be deemed to
have controlling weight. As was shown in Kansas v.
Colorado, 206 U. S. 46
206 U. S. 100
such disputes are to be settled on the basis of equality of right.
But this is not to say that there must be an equal division of the
waters of an interstate stream among the states through which it
flows. It means that the principles of right and equity shall be
applied having regard to the "equal level or plane on which all the
states stand, in point of power and right, under our constitutional
system," and that, upon a consideration of the pertinent laws
Page 282 U. S. 671
of the contending states and all other relevant facts, this
Court will determine what is an equitable apportionment of the use
of such waters. Wyoming v. Colorado, 259 U.
, 259 U. S. 465
259 U. S.
The development of what Mr. Justice Brewer, speaking for the
Court in Kansas v. Colorado, 206 U. S.
, 206 U. S. 98
refers to as interstate common law is indicated, and its
application for the ascertainment of the relative rights of states
in respect of interstate waters is illustrated, by Missouri v.
Illinois, 200 U. S. 496
Kansas v. Colorado, supra; Wyoming v. Colorado, supra,
Wisconsin v. Illinois, 278 U. S. 367
of these cases are much like the one at bar.
Kansas v. Colorado
was a suit to prevent the latter
from withholding waters of the Arkansas River from flowing as they
were wont through Kansas. The common law rule as to riparian
ownership was then generally recognized in Kansas, while in
Colorado the doctrine of appropriation prevailed. The Court held
that the upper state was not entitled to use the waters of the
Arkansas flowing therein as it chose, regardless of resulting
conditions or impairment of the right to the use of such waters in
the lower state. It was shown that, without diversion from the
watershed, the waters of the Arkansas in Colorado were, and for
many years had been, used to irrigate and make productive what
theretofore had been barren lands. It was found that the resulting
diminution of the flow of the river caused perceptible injury to a
portion of the valley in Kansas, but that it had been of little, if
any, detriment to the great body of the valley. The Court held (206
U.S. at 206 U. S. 114
that the rule of equality of right forbade interference with the
existing withdrawals of water in Colorado.
In Wyoming v. Colorado,
the former used to prevent a
diversion of the waters of the Laramie River, which rises
Page 282 U. S. 672
in Colorado and flows into Wyoming. Both states are in the arid
region, and apply the doctrine of appropriation. Wyoming objected
on the ground that the diversion was to another watershed. The
Court held (p. 259 U. S. 467
"The principle of such diversions being recognized in both
states, its application to this interstate stream does not, in
itself, afford a ground for complaint unless the practice in both
be rejected in determining what, as between them, is reasonable and
admissible as to this stream, which we think should not be
The problem there presented was expressed as follows (p.
467 U. S.
"We are thus brought to the question of the basis on which the
relative rights of these states in the waters of this interstate
stream should be determined. Should the doctrine of appropriation,
which each recognizes and enforces within her borders, be applied?
Or is there another basis which is more consonant with right and
After an elaborate discussion of the facts, the Court said (p.
259 U. S.
"We conclude that Colorado's objections to the doctrine of
appropriation as a basis of decision are not well taken, and that
it furnishes the only basis which is consonant with the principles
of right and equity applicable to such a controversy as this
It is very clear that, under earlier decisions here, the strict
rules for which Connecticut contends are not necessarily
controlling in this case. There is nothing in the master's findings
of fact to justify an inference that any real or substantial injury
or damage will presently result to Connecticut from the diversions
by Massachusetts authorized by the Acts of 1926 and 1927 as limited
and defined by the Secretary of War. No discussion is required as
to the effect of the proposed diversion upon the navigability of
the river, agriculture, fish life, or pollution in Connecticut.
Page 282 U. S. 673
The proposed taking of the waters of the Swift and Ware will not
affect the present dam, works, or production of power at King's
Island. While the owning company has secured authority to build the
higher dam, it has not resolved so to do. It is not found, and
there is nothing to show, that it intends to construct any dam or
works of a kind or capacity that, if now in use, would be
injuriously affected by such diversion. At most, there is a mere
possibility that, at some undisclosed time, the owner, were it not
for the diversion, might construct additional works capable of
using all of the flow of the river, including the waters proposed
to be taken by Massachusetts. Injunction will not issue in the
absence of actual or presently threatened interference. The facts
disclose no basis for relief in respect of that property. New
York v. Illinois, 274 U. S. 488
New Jersey v. Sargent, 269 U. S. 328
269 U. S. 331
269 U. S.
Drinking and other domestic purposes are the highest uses of
water. An ample supply of wholesome water is essential.
Massachusetts, after elaborate research, decided to take the waters
of the Ware and Swift, rather than to rely on the sources in the
eastern part of the Commonwealth, where all are or are liable to
become polluted. We need not advert to other considerations,
disclosed by the evidence and findings, to show that the proposed
use of the waters of the Ware and Swift should not be enjoined.
Connecticut maintains that the presently purposed diversion will
not be adequate for the future needs of the Boston district, and
that the size and character of the works, as well as legislative
reports and other circumstances, disclose an intention on the part
of Massachusetts, when the need shall arise, to draw from other
rivers -- Millers, Deerfield, Quaboag, and Westfield -- tributary
to the Connecticut, and insists that the decree should
Page 282 U. S. 674
restrain Massachusetts forever from increasing its diversion to
an amount in excess of what the Secretary of War has already
indicated would cause no damage to the navigation of the
The scope of the project is that shown by the Acts as limited by
the determination of the War Department. It involves no diversion
from streams other than the Ware and Swift. Massachusetts declares
that she intends to and must obey these findings of the War
Department. Her statements before the master and here clearly
negative any threat, intention, or purpose to make any diversion of
water in excess of that specified or otherwise than as set forth in
the determinations of the War Department. Injunction issues to
prevent existing or presently threatened injuries. One will not be
granted against something merely feared as liable to occur at some
indefinite time in the future. New York v. Illinois, supra; New
Jersey v. Sargent, supra.
Connecticut's bill of complaint will be dismissed without
prejudice to her right to maintain a suit against Massachusetts
whenever it shall appear that substantial interests of Connecticut
are being injured through a material increase of the amount of the
waters of the Ware and Swift diverted by or under the authority of
Massachusetts over and above the quantities authorized by the Acts
of 1926 and 1927 as heretofore limited by the War Department. Each
party will pay its own costs, one-half of the expenses incurred by
the special master and one-half the amount to be fixed by the Court
as his compensation.
Counsel for Massachusetts will prepare a form of decree in
consonance with this decision and furnish a copy to counsel for
Connecticut within fifteen days; and, within ten days after such
submission, the draft decree, together with suggestions in behalf
of Connecticut, if any, will be submitted to the Court.