No bridges, culverts, viaducts, watersheds or drainage structures or any structures shall be constructed over, under or in the bed or across any brook, drainage canal or stream unless the same shall have been designed by a licensed professional engineer of the State of New Jersey and reviewed and approved by the Borough Engineer and approved by the Mayor and Council of the Borough of Closter. Such approval shall be denied if, in the opinion of the Borough Engineer, the proposed bridge, culvert, viaduct, watershed or drainage structure or other structure shall obstruct the flow of water in said drainage canal, brook or stream to such an extent as to be liable to cause flooding in the area.