The opinion of the court was delivered, May 24th 1866, by
Strong, J.The jury have found that the dam, as maintained by the defendants below, now plaintiffs in error, is an obstruction to the navigation of the river, but they have not found that it is a nuisance. Whether it is or not is the very question presented by the special verdict. Though an obstruction to navigation, if the dam is authorized by law it is no nuisance, and the defendants are not indictable for maintaining it.
Without the license granted by the Act of March 23d 1803, commonly called the “ Mill-dam Act,” there could be no doubt that the maintenance of the dam would be contrary to law. Any unauthorized obstruction in a navigable stream is a nuisance. But by that act certain dams in such streams are permitted. True, there is a proviso to the grant of the privilege to erect and maintain them, that they shall not obstruct or impede the *323navigation of the stream. Of this it was said, in Bacon v. Arthur, 4 Watts 437, that it must receive a liberal construction, taking special care to preserve the great interests of the Commonwealth, because a literal construction would make it contrary to the grant itself, all dams causing some impediment to the navigation ; and this is evidently correct. The Act of Assembly must be so construed that it shall mean something; and clearly the legislature intended to authorize the erection and maintenance of some dams. But if the proviso is construed literally, either it or the grant must yield, and the rule is that a proviso or exception contrary to a grant is void. Both, however, may stand, if the proviso be construed reasonably in connection with the authority given, as it was manifestly understood by the legislature. A dam is not then unauthorized by the Act of 1803, merely because it is, in some sense, an obstruction. It may be difficult to define precisely the extent of the limitation imposed upon the grant. It would seem, however, that the obstruction spoken of is a substantial impediment, not merely making navigation more difficult, but partially destroying the power of using the stream for navigable purposes. I speak of it now solely in view of its infringement upon public rights. Whether an individual sustaining a private injury peculiar to himself may recover compensation for the injury in a suit at law, is another question not necessary to be decided in this case. Here the defendants are accused of a public wrong. During the argument it was contended .that the Mill-Dam Act does not apply to dams in such streams as were navigable at common law, but only to those declared navigable by Act of Assembly, and that the West Branch of the Susquehanna was not one of them, and hence that is not within the provisions of the act. To this we do not assent. The river Susquehanna, from the Maryland line up to Northumberland, and thence up both its branches meeting at that place, through the whole length of the river, was declared to be a public highway by an Act of Assembly passed March 31st 1785. And the Act of 1803 embraces within its provisions any navigable stream declared by law to be a public highway, except the rivers Delaware, Lehigh and Schuylkill. The exception itself is very significant. There can be no doubt, therefore, that the Mill-Dam Act does authorize dams in the West Branch of the Susquehanna as in other streams not excepted.
The material inquiry in this case then is, whether the defendants are protected by that act ? The special verdict finds that they are owners of land adjoining both sides of the river, that the dam has been constructed from their lands on one side to their lands on the other, that it was erected prior to the 30th of April 1864, that the defendants were indicted for erecting it in 1860, and that they were convicted and sentenced to pay a fine *324and the costs. The verdict also finds that the indictment in 1860 was a proceeding under the 2d section of the Mill-Dam Act, and that the court after the conviction ordered the supervisors of the townships in which the lands lie to remove the obstruction described in the indictment in such a manner as to bring the same (that is, the dam) within the provisions of the Act of Assembly of 1803, at the costs of the defendants. The verdict further finds that the supervisors made alterations in the dam, describes what they were, and finds that they returned to the court that they had removed the obstruction described in the indictment. Still further, the verdict finds that the dam so altered and fixed by the supervisors is the dam which the defendants have maintained from April 30th 1864 at the same height, and in the same condition substantially in which it was made by the supervisors. Is the maintenance of such a dam illegal — an offence for which the defendants can be indicted and punished ? It is plain they are not liable to indictment at common law. The Act of Assembly has provided a remedy for transgression of the power granted by it, and that remedy is exclusive of all others. It permits nothing to be done according to the course of the common law: Brown v. The Commonwealth, 3 S. & R. 273; Cresswell v. Clugh, 3 Watts 330; and Spigelmoyer v. Walter, § W. & S. 540.
The 2d section enacts that on complaint made to the Court of Quarter Sessions of the proper county that any dam built under the act obstructs navigation, the court shall appoint commissioners to view and compare it with the provisions of the act, and to report at the next sessions, whereupon, if it shall appear that air offence against the act has been committed, a bill of indictment shall be sent to the grand jury. And it is further enacted that if the accused be convicted of the offence, he shall be liable to pay a fine and damages to the complainant such as may be found by the jury, and the court is required to direct the supervisors of the adjoining townships forthwith to remove every such artificial obstruction in such manner as to bring the same within the limitations and provisions of the act at the cost of the person so convicted.
This is a very peculiar regulation. The offence, for the redress of w'hich it is provided, is not the erection or maintenance of the dam itself. The violation of law to be removed and punished is the excess beyond the allowed limit. And the manifest purpose of the act is not to cause the dam to be abated, but to make it conform to the statutory license. The mode in which this is accomplished is also peculiar. The act takes the reduction or alteration of the dam entirely out of the handsN of the person convicted of transgression, and commits it to agents of the Commonwealth, for such the supervisors are. They are public officers designated for this particular duty, and the duty is plainly pre*325seribed. They are “ to remove the obstruction in such a manner as to bring the same within the limitations and provisions of the act.” In so doing they must exercise their judgment. Neither the judgment of the court, nor that of the jury, are invoked by the law to determine the manner in which the obstruction is to he reduced within the limits allowed by the 1st section of the act. All that is settled by the verdict of the jury, and the judgment of the court, is that the licensee exceeded his license. How much, in what particular, and what must he done to remove the excess, are questions committed to the supervisors, without any provision for a review of their decision. With their discretion and with their action certainly the convicted person cannot interfere. And when their action has been completed, and the dam has been eon-' formed to their judgment of what the act allows, an alteration of it afterwards by any person, unless the alteration be entire removal, would be unwarranted, for it would be interference with the action of the Commonwealth. Under the law the supervisors are more than executive officers of the court. The sheriff would suffice to carry into effect a sentence to abate the dam. But they have discretionary and executive duties to perform. They must determine what are the limitations and provisions of the act, what is the extent of the license it grants, and they must make the dam conform to it. It would be strange, indeed, if their judgment and their action could be revised collaterally by successive juries. If it can be, a jury becomes the final judge of conformity to the provisions of the law instead of the persons designated by the Commonwealth for that duty.
The Act of Assembly clearly contemplates but one prosecution, the result of which is to be the removal of all that is transgression of the statutory license. We shall mistake if we assimilate it to an indictment at common law for a nuisance. In such an indictment, the defendant, if convicted, is adjudged to abate the nuisance. The Commonwealth does not undertake to do it. If, therefore, it be not abated, or only partially removed, he may he again indicted for continuing it. He is in fault. Not so under the Act of 1803, when he must take the dam as it is left by the supervisors. And it is obvious that the mode in which they secure conformity to the provisions of the act is not material. It is not to be doubted that navigation may be improved or restored, if obstructed by a dam, in many ways. It may be done by raising the dam and altering the sluice or water-way in the channel of the stream. The Act of Assembly has left to the supervisors the choice of the mode as well as the extent to which the necessary alterations must be made. Regarding then these officers as the chosen agents of the Commonwealth, endowed with power to reform the dam and bring it within its authorized limits, it must be that as against the Commonwealth their action determines that *326the dam as reformed by them is not illegal, and that it is no longer an obstruction within the meaning of the 1st section of the act, therefore not a public nuisance. If this is not so, these defendants are guilty of an offence committed not by themselves, but by the public that complains of it, an offence they had no power to prevent.
It was urged in the argument that this construction of the powers and duties of the supervisors enables them practically to close the navigation of rivers without responsibility to the law. To this it may be answered that the public rights are abundantly protected. Eor any neglect or corrupt action of the supervisors they are amenable to the criminal law, and for their misconduct or mistake there is a remedy in the power of the legislature to revoke, at any time, in whole or in part, the license granted. The private rights of every navigator are secured by the provisions of the Act of Assembly of May 31st 1841, Pamph. L. 416.
We hold therefore that the former indictment and the proceedings thereunder are a protection to these defendants; that the dam as it stood on the 30th of April 1864, and as it has been since maintained by the defendants, is not illegal, and hence that there was error in giving judgment for the Commonwealth on the special verdict.
The judgment of the Court of Quarter Sessions is reversed, and judgment is now entered for the defendants. But the jury having found that the defendants pay the costs of prosecution, the record ys remitted with instructions that they be sentenced accordingly, as directed by the Act of Assembly.