A. 
Basis of districts. The various floodplain districts shall include areas subject to inundation by waters of the one-hundred-year flood. The basis for the delineation of these districts shall be the Flood Insurance Study prepared by the Federal Insurance Administration, dated August 1, 1979.
(1) 
The Floodway District (FW) is delineated for purposes of this part using the criteria that a certain area within the floodplain must be capable of carrying the waters of the one-hundred-year flood without increasing the water surface elevation of that flood more than one foot at any point. The Floodway District is shown on the companion to the Official Zoning Map. The areas included in this district are defined in the above-referenced Flood Insurance Study (FIS) and as shown on the accompanying flood boundary and floodway map.
(2) 
The Flood-Fringe District (FF) shall be that area of the one-hundred-year floodplain not included in the Floodway District. The basis for the outermost boundary of this district shall be the one-hundred-year flood elevations contained in the flood profiles of the above-referenced Flood Insurance Study (FIS) and as shown on the accompanying flood boundary and floodway map.
B. 
Overlay concept.
(1) 
The floodplain districts described above shall be overlays to the existing underlying districts as shown on the Official Zoning Ordinance Map and, as such, the provisions for the floodplain districts shall serve as a supplement to the underlying district provisions.
(2) 
Where there happens to be any conflict between the provisions or requirements of any of the floodplain districts and those of any underlying district, the more restrictive provisions and/or those pertaining to the floodplain districts shall apply.
(3) 
In the even any provision concerning a floodplain district is declared inapplicable as a result of any legislative or administrative actions or judicial discretion, the basic underlying district provisions shall remain applicable.
The boundaries of the floodplain districts are established as shown on the Official Zoning Map of the Borough, which is declared to be a part of this part and which shall be kept on file at the Ambridge Borough offices.
The delineation of any of the floodplain districts may be revised by the Borough Engineer where natural or man-made changes have occurred and/or more detailed studies conducted or undertaken by the U.S. Army Corps of Engineers, River Basin Commission or other qualified agency or individual document the need or possibility for such change. However, prior to any such change, approval must be obtained from the Federal Insurance Administration (FIA).
Initial interpretations of the boundaries of the floodplain districts shall be made by the Zoning Officer. Should a dispute arise concerning the boundaries of any of the districts, the Zoning Hearing Board shall make the necessary determination. The person questioning or contesting the location of the district boundary shall be given a reasonable opportunity to present his case to the Board and to submit his own technical evidence if he so desires.