This is a suit in equity to enjoin the defendants, who constitute the Charles River Basin commission, from increasing the depth of the water over the plaintiffs’ flats, a large part of the time, by maintaining the dam required to be built by the St. 1903, c. 465, as amended by St. 1906, c. 402. The plaintiffs are the owners of many acres of flats in the Charles River, extending southward from the shore in Cambridge. These lie at such a level as to be, for the most part, just uncovered at low tide. The maintenance of the dam will keep them constantly covered, to a depth of about eight feet. Beneath a thin layer of mud, there is, in the flats, a valuable deposit of sand and gravel, which can be used in building, and from which the plaintiffs have been accustomed to take large quantities for sale, under a license from the harbor and land commissioners and another license from the secretary of war of the United States. The title of the plaintiffs to the flats is under the Colonial Ordinance of 1647, and it is not contended that the erection and maintenance of the dam will affect any of their property except that below high water mark, which is held under this ordinance. The commission has not taken any part of the property of the plaintiffs, unless the increase of the depth of the water a large part of the time constitutes a taking, and there is no provision in the statute for compensation for this effect upon their property. The power of the Legislature *441to authorize the erection and maintenance of the dam was considered at length in the Home for Aged Women v. Commonwealth, ante, 422, and it was held that the enactment of the law was a lawful, exercise of the power of the government, for the improvement of navigation and for other public purposes. It appears from the evidence that it will materially benefit navigation for industrial and commercial purposes, as well as navigation for pleasure, which is equally within the control of the State, and is recognized and encouraged under our laws. Attorney Greneral v. Woods, 108 Mass. 436, 439. The fact that considerations of the public health and the public comfort were also involved is immaterial in this case.
The question is whether this increase in the depth of the water where the tide ebbs and flows is a taking of the plaintiffs’ property. Were it not for the rights acquired by the plaintiffs under the Colonial Ordinance, there would be no question. There would be a mere change in property held by the State for a public use. Did the extension of the boundaries of private ownership, under the Colonial Ordinance, take away from the State the right to make such a change, for the improvement of navigation, without providing compensation to individual owners under the ordinance? We are of opinion that it did not. This ordinance gave to the owners only qualified rights. Treating it as a grant, the rights of the public to have the benefit of the waters for navigation, fishing and fowling were reserved. Butler v. Attorney General, 195 Mass. 79, 83. These include a right to control the property, so far as is reasonably necessary in the interests of navigation. This is the substance of the decision in Commonwealth v. Alger, 7 Cush. 53, 89, 91, in which it was held that the Commonwealth might establish harbor lines over flats in private ownership that had not been built upon, and exclude the owner from any use of them inconsistent with the most advantageous use that the public might make for purposes of navigation. This doctrine has been embodied in our legislation and in our decisions. R. L. c. 96, §§ 3, 14, 25. The statutes of the United States rest upon the same view of the law. U. S. St. of March 3, 1899, c. 425, § 10. 30 U. S. Sts. at Large, 1151. In Boston v. Richardson, 105 Mass. 351, 362, Mr. Justice Gray said: “ Even a title in flats by grant from the *442colony or Common wealth, is subject, so long as they have not been built upon, to the authority of the Legislature, for the protection of the harbors and of the public right of navigation, to prohibit the taking of sand or gravel from the shore, or the erection of wharves beyond certain lines. Commonwealth v. Tewksbury, 11 Met. 55. Commonwealth v. Alger, 7 Cush. 53. Boston v. Lecraw, 17 How. 426, 433."
Such owners are not entitled to have the flow of water continue in its accustomed manner if the interests of the public require a change for the improvement of navigation. Fitchburg Railroad v. Boston & Maine Railroad, 3 Cush. 58, 88. Davidson v. Boston & Maine Railroad, 3 Cush. 91, 105, 106. The result in this case does not depend upon a suggestion that action in the interest of the public health and of the public comfort was an exercise of the police power, and for that reason justified an appropriation of property for the public benefit without compensation. Restriction and limitation upon the use of property, and even the destruction of property without compensation, is allowable in the exercise of the police power, if the use or continued existence of the property is dangerous or very harmful to the public. But to take property which is harmless and is being properly used, and to appropriate it to the improvement of the public health, is a different thing. Such a taking and appropriation, although for an object which it is within the police power to accomplish, calls for compensation. If the effect of this erection ‘were permanently to inundate the plaintiffs’ houses and lands above high water mark, the purpose of the Legislature would leave the effect a taking that must be paid for.
Our decision rests upon the ground that this improvement in navigation was one which, apart from the ordinance of 1647, the Government would have had a right to make as owner of the soil and as the representative of the public, and that the ordinance creating private property in flats reserved this right for the benefit of all the people. •
The decision in Bent v. Emery, 173 Mass. 495, had reference to a removal of the substance of the land of the plaintiff, and the appropriation oi it, under the contract for dredging, to use in the filling of flats in another place. In Butler v. Attorney Gen *443eral, 195 Mass. 79, 83, it is held that the private ownership of flats is subject to public rights, of which the right of navigation is one. The point under discussion was whether the public had a right to use the land on the beach for bathing, either under the water or along its edge. These cases are not at variance with the contention of the defendants.
Bill dismissed.