"Groundwater sensitivity" means a measure of the ease with which groundwater enters and moves through both the unsaturated and saturated zones; it is a characteristic of the aquifer and overlying material and hydrologic conditions, and is independent of the chemical characteristics of the contaminant and its sources. (Added by Amended Ord. 06-061, Aug. 1, 2007, Eff date Oct. 1, 2007).