A power dam or change in stream to develop power shall be deemed to be within the jurisdiction of the United States, within the meaning of this section, whenever (1) such dam or change is constructed or made, or to be constructed or made, in or upon navigable waters of the United States, or (2) the Federal Power Commission shall have found that the interests of interstate or foreign commerce would be affected by the construction of such dam or the making of such change.

Every permit hereafter granted by the commission¹ for the construction of a power dam or for a change in stream to develop power, not within the jurisdiction of the United States, shall be limited to such periods not exceeding fifty years as the said commission shall determine and set forth therein: Provided, That the permittee shall be entitled to extension and renewal of such permit upon the terms thereof until the permittee shall have received through recapture or purchase by the Commonwealth, or by a duly authorized subsequent permittee, repayment of the capital prudently invested in the power project upon the faith of the permit, plus such reasonable damages, if any, to property of the permittee valuable, serviceable, and dependent for its usefulness upon the continuance of such permit, but not recaptured or purchased, as may be caused by the severance therefrom of property taken.

Every permit hereafter granted by the commission for the construction of a power dam or for a change in stream to develop power, within the jurisdiction of the United States, shall be on the following conditions, which shall be expressed in such permit, namely: (a) That the permit shall become null and void unless, within the time specified therein, the permittee (or, as to a change in stream within the Commonwealth effected or to be effected by a dam or other means without the Commonwealth, those constructing or purposing to construct, maintain, or operate such dam or other means) shall secure from the Federal Power Commission a license for such dam or change; and (b) that if and to the extent that any of the rights or powers set forth or reserved as rights or powers of the United States in or pursuant to the provisions of such license shall be waived by the United States or be unenforceable by the United States, then and to that extent such rights and powers (including, if so waived or unenforceable, any rights of recapture, extension, or renewal so set forth or reserved) may be exercised and enforced by the Commonwealth of Pennsylvania, subject to such alterations in plans, specifications, or structures, and such extensions of time for commencing or completing construction, as may be made or granted by the Federal Power Commission.

The provisions of this act relating to dams or changes in streams to supply water for steam power within the jurisdiction of the United States shall be suspended and postponed until the Federal Power Commission shall require licenses for such dams or changes in streams; and during the period in which the provisions of this act shall be so suspended and postponed, any such dams or changes in streams shall continue to be subject to existing laws relating to water obstructions.

Every permit granted under this section shall be subject to such reasonable annual charge, specified therein, as the commission shall fix, for the purpose of reimbursing the Commonwealth for the costs of administration of this act, and may, in the discretion of the commission, embody such other terms, conditions, and stipulations as the commission shall deem necessary to protect the present and future interests of the Commonwealth and its people in the construction, maintenance, and operation of the project, and in the water and power resources to be utilized thereby, and suitable to secure to the permittee a reasonable opportunity for a fair return on the actual investment prudently made in the project.