The paved portion of all sidewalks or the sidewalk pavement where there is a grass plot between it and the curb, may, at the direction of the Engineer with the approval of Council, be placed above or below the elevation of the curb in order to conform as nearly as practicable to the topography of the abutting land and street; provided, that the slope of such grass plot shall not be steeper than one and one-half horizontal to one vertical. Where the sidewalk pavement is placed above or below the elevation of the curb, the owner of the corner lot shall provide concrete steps from such sidewalk pavement to the curb, such steps to be of similar materials and workmanship as the sidewalk pavement and the design thereof to be approved by the Engineer.