(A) The various floodplain districts shall include the special flood hazard area (SFHA). The basis for the delineation of these districts shall be the flood insurance study (FIS) and Panel 51153C0217 D of flood insurance rate map (FIRM) prepared by the Federal Emergency Management Agency for Prince William County, Virginia and Incorporated Areas, dated August 3, 2015 and January 5, 1995, respectively as amended or revised.
(B) The floodway district is delineated, for purposes of this chapter, using the criterion that certain areas within the floodplain must be capable of carrying the waters of the base flood without increasing the water surface elevation of that flood more than one foot at any one point. The areas included in this district are specifically defined in the flood insurance study and shown on the accompanying FIRM.
(C) The flood fringe district shall be that area of the 1% annual chance floodplain not included in the floodway district. The basis for the outermost boundary of this district shall be the base flood elevations contained in the flood profiles of the flood insurance study and as shown on the accompanying flood insurance rate map.
(D) The approximated floodplain district shall be that floodplain area for which no detailed flood profiles or elevations are provided, but where the SFHA floodplain boundary has been approximated. Such areas are shown as zone A on the maps accompanying the flood insurance study. For these areas, the BFE and floodway information from federal, state, and other acceptable sources shall be used, when available. Where the specific BFE cannot be determined for this area using other sources of data, such as the U.S. Army Corps of Engineers Floodplain Information Reports, U.S. Geological Survey Flood-Prone Floodplain Information Reports, and U.S. Geological Survey Flood-Prone Quadrangles, the applicant for the proposed use, development, and/or activity shall determine this elevation in accordance with hydrologic and hydraulic engineering techniques. Hydrologic and hydraulic analyses shall be undertaken only by professional engineers or others of demonstrated qualifications, who shall certify that the technical methods used correctly reflect currently accepted technical concepts. Studies, analyses, computations, and similar data or reports shall be submitted in sufficient detail to allow a thorough review by the town.
(1998 Code, § 26-36) (Ord. O-2016-01, passed 2-2-2016)