Improvement work shall not be commenced until plans and profiles for such work have been submitted to and approved by an engineer duly specified by the city council. Such plans shall be required before approval of the final maps. All such plans and profiles shall be prepared in accordance with requirements of the engineer duly specified by the city council. Duplicate tracings on drafting film shall be filed with the engineer duly specified by the city council. (Ord. 90-1 (part), 1990)