The Approximated Floodplain District shall be that floodplain
area for which no detailed flood profiles or elevations are provided,
but where a one-hundred-year floodplain boundary has been approximated.
Such areas are shown as Zone A on the maps accompanying the FIS. For
these areas, the base flood elevations and floodway information from
federal, state, and other acceptable sources shall be used, when available.
Where the specific one-percent-annual-chance flood elevation cannot
be determined for this area using other sources of data, such as the
United States Army Corps of Engineers Floodplain Information Reports,
United States Geological Survey Flood-Prone Quadrangles, etc., then
the applicant for the proposed use, development and/or activity shall
determine this base flood elevation. For development proposed in the
approximate floodplain, the applicant must use technical methods that
correctly reflect currently accepted nondetailed technical concepts,
such as point on boundary, high-water marks, or detailed methodologies
hydrologic and hydraulic analyses. Studies, analyses, computations,
etc., shall be submitted in sufficient detail to allow a thorough
review by the Floodplain Administrator.