This case depends principally upon the rights of the parties at common law. The rights of riparian proprietors to vary the natural flow of a stream in order to use it most advantageously for the working of mills was thoroughly considered in the case of Gould v. Boston Duck Co. 13 Gray, 449. In that case the plaintiff was proprietor of an ancient mill. The defendants had, within twenty years, built a factory a short distance above the plaintiff’s mill, and erected a dam across the stream, by means of which they raised a large pond. Their works did not, in ordinary stages of the water, affect the plaintiff’s mill; but the size of their factory was adapted to the usual flow of the stream; and therefore it Happened that in times of very low water it required more power than they could derive from the natural flow to drive their machinery. In the latter part of the day their pond was drawn down considerably below the top of the dam, and they ceased to have a sufficient head *580They then shut their gates, and stopped the flow of the water till their pond became full. When they hoisted their gates the next morning, they let down, for the purpose of carrying their works, a much larger quantity of water than the plaintiff could use at his smaller mill. It was held that a riparian proprietor might thus disturb and vary the natural flow of a stream, for the purpose of driving machinery, notwithstanding its injurious effect upon an ancient mill below him. The right is founded upon the consideration that water power is property of great value, and that a large part cf the power must run to waste if mills may not be constructed sufficiently large to use all the power of the stream at its ordinary height; and, if mills of such a character may be constructed, it is but reasonable that the proprietor should have a right to husband the power in seasons of extraordinary drought, so that he may use it most advantageously, and not be compelled to let his machinery and workmen remain entirely idle till the stream may be raised by rains. It is a reasonable use of his right with reference to the proprietors below him. If they use the whole power of the stream, it benefits them equally with himself. It is only when they allow a part of their power to run to waste in ordinary stages of the water that they are injured by such use; and the injury to them is comparatively trifling. This interpretation of the rights of riparian proprietors tends to promote the interests of the public, because it enables the owners of water power, which has proved to be a species of property of great value to the public, to avail themselves of it to the utmost extent that can be deemed reasonable.
It is obvious that this exercise of the right to vary the natural flow of the stream not only affects the mill owner immediately below, but affects the stream for a considerable distance, at some times increasing its volume, and at other times diminishing it. And the proprietor may make his pond as large as the situation of the land above him will permit, thereby creating a large reservoir to be used in seasons of drought, and varying the flow of the stream. He may also erect a dam far above his mill, to be used merely as a reservoir dam. He is authorized by our stat* *581utes to flow the land above such dam on payment of damages. Wolcott Manufacturing Co. v. Upham, 5 Pick. 292. Shaw v. Wells, 5 Cush. 538. By means of such a dam he may hold back the water in his reservoir till he needs it for his works in a season of drought, and then let it down in such quantities as considerably to increase the volume of the stream. Such reservoir dams are becoming more important than they formerly were, because the clearing, cultivation and drainage of marshy and swampy grounds is gradually destroying the natural reservoirs which formerly supplied more or less water to most of our streams through the whole year. The principal question raised in the present case is, to what extent a riparian proprietor, who has erected a reservoir dam for the benefit of his mill situated at a distance of several miles below, may so let down the water in seasons of drought as to increase the volume of the stream, without exceeding his rights as such proprietor, and becoming liable to pay damages to intermediate proprietors for the interruption it may occasion to the drainage of their lands. The court are of opinion that it is not an unreasonable exercise of his rights to increase the volume of the stream to any extent that shall not exceed the usual and ordinary flow, nor overflow the natural banks. This will enable the proprietors of mills to avail themselves of all the power which a reasonable use of the stream affords, and will subject the proprietors of the lands that border on the stream to no unreasonable burden.
In the present case it does not appear that, if the natura, channel had been left unobstructed below the complainant’s land, any injury would have been done to him. On the contrary, it is found that the water which came from the respondents’ reservoir dam would pass off within the natural banks. But Mr. Fuller, the former proprietor of- the complainant’s land executed a deed to Ezra Perry, Jr., conveying to him, his heirs and assigns forever, the right, title and privilege to flood and flow, at all seasons of the year, all the land he owned in Holland, that could be flowed by a certain dam, and describing the dam that has ever since existed below the complainant’s land. This is a right to flow the land by means of any water that any *582party would have a right at common law to send down the stream. It is by means of this dam that the stream is raised above its natural banks so as to overflow the complainant’s meadow in the manner described in the complaint. But for this artificial structure, which has been erected under a right derived from the complainant’s grantor, the water would have passed off in the natural channel. The acts of the respondents are not therefore the direct cause of the injury complained of. They would not cause the water to overflow the banks; but the structure below raises it up and causes it to spread over the meadow. The respondents have merely exercised their riparian rights; and, upon the facts found by the referees, the complainant has no cause of action. Exceptions sustained.