Fence height shall be measured as the vertical distance directly above, and consistent with an imaginary plane, parallel to the natural or finished grade, whichever is lower, at the base of the fence, including the height of any retaining wall attached to, or within one foot of, the fence. In the case where a grade differential exists on opposite sides of a fence, the height shall be measured from the lower grade. (Ord. 1030 § 2(12), 2018; Ord. 953 § 1(5), 2007)