KOHLSAAT, Circuit Judge,
(after stating the facts as above). As usual in such cases, the testimony is conflicting. Out of the vast volume of it, however, the District Court, which heard and saw the witnesses, must have found, and doubtless did find: (1) That defendant’s discharge of from 3,000,000 to 4,000,000 gallons per day into the Rock river during the ice-forming weather conditions, at a temperature of from 50° to 60°, resulted in an increase of the temperature of the water of the river opposite and adjoining complainant’s plant, or that part thereof used by complainant as and for its ice-cutting field, of 47/ioo°; (2) that such increase in temperature was sufficient to and did practically retard the formation* at the times when it would be otherwise naturally produced, of ice thereon of a commercial charac*203ier, to a degree which made it impossible for complainant to conduct its said ice business at a profit; (3) that, in order to protect the interests of complainant in the premises, the defendant should desist oi be restrained from emptying into the river at its plant hot water fiom its condensing or other machinery in such a manner as will tend to increase the temperature of the water in complainant’s said ice field during ice-forming weather, provided the court has the power so to do under the circumstances of this case without unlawful interference with the rights of defendant as the owner or lessee of its said riparian rights. These deductions of fact we accept as fairly sustained by the evidence, reinforced by the presumptions which attend the finding of the trial court.
[1] That each riparian owner is entitled to the reasonable use of the water of Rock river at its respective site is too well settled to require citation. The question presented is: Was the use made of the upper riparian rights here involved a reasonable use thereof? if so, the complainant may not complain, even though it suffer some injury incidental thereto. Dumont v. Kellogg, 29 Mich. 420, 18 Am. Rep. 102; Gehlen Bros. et al. v. Knorr et al., 101 Iowa, 700, 70 N. W. 757, 36 L. R. A. 697, 63 Am. St. Rep. 416; Elliott v. Fitchburg Ry. Co., 10 Cush. (Mass.) 191, 57 Am. Dec. 85; Lockwood Co. v. Lawrence, 77 Me. 297, 52 Am. Rep. 763; Beidler v. Sanitary District, 211 Ill. 628, 71 N. E. 1118, 67 L. R. A. 820. Says the court in the last-named case:
“Tile limitation and extent oí the use of the water is that it shall not interfere with the public right of navigation, nor in a substantial degree diminish and impair the right of use of the water by other riparian owners.”
In Palmer v. Mulligan, 3 Caines (N. Y.) 307, 2 Am. Dec. 270, it was held lhat the upper owner had the right to erect a dam, when necessary for the enjoyment of his riparian rights, even though such obstruction necessitated increased expense on the part of the lower owner and greater difficulty in getting logs to his mill, provided enough water was left to work the lower mill. To the same effect is Gould v. Boston Duck Co., 13 Gray (Mass.) 442.
So in Keeney & Wood Manufacturing Co. v. Union Manufacturing Co., 39 Conn. 576, where the upper owner was obliged 1o run his mill by day only, and where he allowed the water to accumulate overnight to the injury of the lower owner, whose mill ran day and night, a restraining order was denied. It was there held that each had the right to a reasonable use of the running water; that the burden of showing unreasonable use by the upper owner was on the lower owner; that in deciding the conflicting rights the court should consider (1) the-custom of the country; (2) the local custom; (3) what general rule will best secure the entire stream to useful purposes; and (4) whether the injury to the lower owner does not arise from the insufficiency of his own privilege.
[2] It is the duty of each of the riparian owners to use all reasonable effort and means to avoid interference with each other’s use of the water, and the burden is on the lower owner to show that its damages are substantial and are caused by the unreasonable acts of the upper owner.
*204[3, 4] It appears from the evidence that to restrain defendant from emptying its heated water into Rock river will result in great hardship and expense, so that the injury to complainant and defendant’s unreasonable use must be clearly established. Complainant may not insist on such a use of the water by the defendant as will deprive the latter of any use thereof which may be necessary for its business purposes, provided complainant can by reasonable diligence and effort make the flowing water reasonably answer its own purposes. There must be a fair participation between them. “When questions arise between riparian owners respecting the right of one to make a particular use of the water in which they have a common right, the right will generally depend on the reasonableness of the use and the éxtent of the detriment to the lower owner.” Tetherington v. Donk Bros. Coal Co., 232 Ill. 522, 83 N. E- 1048. But where, as in the present case, it is shown by the evidence that defendant’s use of the river water, while essential for its own purposes, entirely destroys the right of complainant thereto, there can be no claim by defendant that its use thereof is reasonable. In other words, the emergency of defendant’s needs is not the measure of its rights in the water. 40 Cyc. 563, and cases there cited; Strobel v. Kerr Salt Co., 164 N. Y. 303, 58 N. E. 142, 51 L. R. A. 687, 79 Am. St. Rep. 643.
The running of water in a heated state down upon a lower riparian owner has several times been before the courts. In Mason v. Hill, 5 B. & A. 11, damages so sustained were awarded and allowed to stand. “However great his ’ necessity,” says the court in Walker Ice Co. v. American Steel & Wire Co., 185 Mass. 463, 70 N. E. 937, “one riparian owner would have no right to foul the water of a stream or turn in hot water to the injury of another riparian owner”—citing Merrifield v. Lombard, 13 Allen (Mass.) 16, 90 Am. Dec. 172.
[5] The pollution of a stream constitutes the taking of property, which may not be done without compensation. Tetherington v. Donk Bros. Coal Co., supra; Elliott v. Fitchburg Ry. Co., supra. In Tipping v. Eckersley, 2 Kay & Johnson, 264 (69 Eng. Reprint 779), the court held that to use water, and return it into the stream heated to such a temperature as to make it unfit for use below, was an unreasonable use thereof. The general rule is well stated in the case of Lancey v. Clifford, 54 Me. 487, 92 Am. Dec. 561:
“Each, proprietor may make any use of the water flowing over his premises which does not essentially or materially diminish the quantity, corrupt the quality, or detain it so as to deprive other proprietors, or the public, of a fair and reasonable participation in its benefits. Race v. Word, 30 Eng. L. & Eq. 187; Johnson v. Jordon, 2 Metc. [Mass.] 234, 37 Am. Dec. 85; Dickinson v. Grand Junction Canal Co., 7 Ex. 282; Tyler v. Wilkinson, 4 Mason, 397, Fed. Cas. No. 14,312. This rule does not require that there shall be no diminution, abstraction, or detention whatever, by the lower or upper riparian proprietor, as that would be to prevent all reasonable use of it. The same principal in regard to use by the riparian proprietors, applies, as in the public use of the stream as a highway; it must be a reasonable use, and not inconsistent with the reasonable enjoyment of the stream by others who have ah equal right to its use. Reasonable use is the touchstone for determining the rights of. the respective parties.”
Authorities to the same effect might be multiplied indefinitely. We do not deem it necessary. We conclude that the use made by defendant *205of the said water of Rock river, taken in connection with its discharge of the heated return water into said river, was an unreasonable use of the flowing water of said river, that the same was an unwarranted interference with the riparian rights of the complainant, and that complainant was entitled to have defendant restrained from continuing its said unreasonable acts.
The decree of the District Court is affirmed.