No grades shall be altered from those shown of the grade sheets of such survey and report except after careful review by a qualified engineer of the effect of any such change upon the property affected by such change and upon the effect of such change upon the overall drainage plan for the city as disclosed and established by such survey and report, and his written determination that such change will not adversely affect any property and will not adversely affect the city’s overall drainage plan. If it appears that any change will in any manner affect adversely any property, public hearing shall be provided for, and notice thereof to all interested parties, before then the city council shall initiate any change in grades. (Ord. 233 § 3, 1961)