This chapter applies to mills and dams erected upon streams forming the boundary line of the State although a part of the dam is not in the State. The rights and remedies of all parties concerned shall be ascertained and determined as if the whole of such streams were in the State. This chapter shall not apply to mills and dams erected upon streams whose waters ultimately reach the ocean at a point wholly outside the territorial limits of the United States of America unless said dams are authorized by Act of the Legislature or by a decree of the Public Utilities Commission made after public notice and hearing on petition for such authorization.