The boundaries of the one-hundred-year floodway shall be determined by scaling distances on the official floodplain maps and using the floodway data table contained in the Flood Insurance Study Report. The maps may be used as a guide for determining the one-hundred-year floodplain boundary, but the exact location of the floodplain boundary shall be determined where the base flood elevation intersects the natural ground. For unnumbered A Zones and AO Zone floodplains, where there is a conflict between a mapped floodplain boundary and actual field conditions, the floodplain administrator may interpret the location of the one-hundred-year floodplain boundary based on field conditions or available historical flood information. (Ord. 576 § 4(D), 1994)