“Natural grade” means that local soil or rock on the property that has existed legally on such property unmoved by natural or unnatural forces for a period of not less than 60 months prior to submittal of an application for a building permit, or in the case of properties that are part of a final plat approval that is still in effect per GHMC 16.06.006, the grade approved by the civil permit. (Ord. 1307 § 14, 2014; Ord. 573 § 2, 1990).