In all areas identified as numbered and unnumbered A zones and AE zones, where base flood elevation data have been provided, as set forth in § 152.25(B), the following provisions are required.
(A) Residential construction. New construction or substantial improvement of any residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated to one foot above base flood elevation. (In all unnumbered and numbered A zones and AE zones, the FEMA Region VII office recommends elevating to one foot above the base flood elevation to accommodate floodway conditions when the floodplain is fully developed.)
(B) Nonresidential construction. New construction or substantial improvement of any commercial, industrial, or other nonresidential structures, including manufactured homes, shall have the lowest floor, including basement, elevated to one foot above the base flood elevation or, together with attendant utility and sanitary facilities, be flood-proofed so that below the base flood elevation the structure is water-tight 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. A registered professional engineer or architect shall certify that the standards of this subsection are satisfied. Such certification shall be provided to the Floodplain Administrator as set forth in § 152.11(B)(9). (The FEMA Region VII office recommends elevating to one foot above the base flood elevation to qualify for flood insurance rates based upon flood-proofing.)
(C) Equalizing hydrostatic flood forces. For all new construction and substantial improvements, fully enclosed areas below lowest floor used solely for parking of vehicles, building access, or storage in an area other than a basement and that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:
(1) A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided; and
(2) The bottom of all opening shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.
(Ord. 11-006, passed 4-5-2011)