The City Administrator will determine the distance between the improved sidewalk and the property line, which, in residential areas, is generally two feet unless a different distance is specified. The width of the improved sidewalks, the grade thereof, materials for construction or reconstruction, and the location and size of curbs, will be designated by the City Administrator. The class and kind of any fill materials and requirement thereof will be designated by the City Administrator. Based on a finding of necessity, the City Administrator may permit installation of a temporary sidewalk for a specified period, and the City Administrator will designate specifications for the temporary improvement.