71. Notwithstanding any inconsistent provision of any general law or special Act, no person shall erect and maintain a dam, dike, causeway, sluice, embankment or other work serving to retain the waters of a lake, pond, river or stream unless the plans and specifications relating thereto have been approved by the Government, except in the case of works for which plans and specifications must be submitted for the approval of the Government under other provisions of this Act or of works of a temporary nature contemplated in section 39.