Standards for Areas of Shallow Flooding (Zone AO).
Located within the Special Flood Hazard Areas established in §42-233.2 (Basis for Establishing the Special Flood
Hazard Areas) designated as shallow flooding areas. These areas have special flood hazards associated with base
flood depths of one (1) to three (3) feet where a clearly defined channel does not exist and where the path of
flooding is unpredictable and indeterminate. In addition to §42-235.1 (General Standards) and §42-235.2 (Specific
Standards), all new construction and substantial improvements shall meet the following requirements:
The reference level shall be elevated at least as high as the depth number specified on the FIRM, in
feet, plus a freeboard of two (2) feet, above the highest adjacent grade; or at least four (4) feet above
the highest adjacent grade if no depth number is specified.
Nonresidential structures may, in lieu of elevation, be flood proofed to the same level as required by
§42-235.7 (Standards for Areas of Shallow Flooding (Zone AO)) (1) so that the structure, together
with attendant utility and sanitary facilities, below that level shall be watertight with walls substantially
impermeable to the passage of water and with structural components having the capability of resisting
hydrostatic and hydrodynamic loads and effects of buoyancy. Certification is required in accordance
with §42-350 (Floodplain Development Permits) C (2) (Certification Requirements) and §42-235.2
(Specific Standards) B (Nonresidential Construction).
C. Adequate drainage paths shall be provided around structures on slopes, to guide flood waters around
and away from the structures.