((a)) If the Secretary of the Army, acting through the Chief of Engineers finds that the proposed project to be erected at the location to be declared nonnavigable under this section is in the public interest, on the basis of engineering studies to determine the location and structural stability of any bulkheading and filling and permanent pile-supported structure, in order to preserve and maintain the remaining navigable waterway, and on the basis of environmental studies conducted pursuant to the National Environmental Policy Act of 1969 [ et seq.], then those portions of the Hackensack River in Hudson County, State of New Jersey, bounded and described as follows are hereby declared to be nonnavigable waters of the United States within the meaning of the laws of the United States, and the consent of Congress is hereby given to the filling in of all or any part thereof and the erection of permanent pile-supported structures thereon:

((b)) The declaration in subsection (a) of this section shall apply only to portions of the described area which are either bulkheaded and filled or occupied by permanent pile-supported structures. Plans for bulkheading and filling and permanent pile-supported structures shall be approved by the Secretary of the Army, acting through the Chief of Engineers. Local interests shall reimburse the Federal Government for engineering and all other costs incurred under this section.