In all areas of special flood hazard, the following provisions, in addition to those set forth in § 153.40 of this chapter are required.
(A) Residential structures.
(1) In AE Zones where base flood elevation data is available, new construction and substantial improvement of any residential building (or manufactured home) shall have the lowest floor, including basement, elevated to no lower than one foot above the base flood elevation. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate equalization of flood hydrostatic forces on both sides of exterior walls shall be provided in accordance with the standards of division (C) below.
(2) Within approximate A Zones where base flood elevations have not been established and where alternative data is not available, the Administrator shall require the lowest floor of a building to be elevated to a level of at least three feet above the highest adjacent grade (as defined in § 153.05 of this chapter). Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate equalization of flood hydrostatic forces on both sides of exterior walls shall be provided in accordance with the standards of division (C) below.
(B) Non-residential structures.
(1) In AE Zones, where base flood elevation data is available, new construction and substantial improvement of any commercial, industrial, or non-residential building, shall have the lowest floor, including basement, elevated or floodproofed to no lower than one foot above the level of the base flood elevation. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate equalization of flood hydrostatic forces on both sides of exterior walls shall be provided in accordance with the standards of division (C) below.
(2) In approximate A Zones, where base flood elevations have not been established and where alternative data is not available, new construction and substantial improvement of any commercial, industrial or non-residential building, shall have the lowest floor, including basement, elevated or floodproofed to no lower than three feet above the highest adjacent grade (as defined in § 153.05 of this chapter). Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate equalization of flood hydrostatic forces on both sides of exterior walls shall be provided in accordance with the standards of division (C) below.
(3) Non-residential buildings located in all A Zones may be floodproofed, in lieu of being elevated; provided that, all areas of the building below the required elevation are water-tight, with walls substantially impermeable to the passage of water, and are built with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. A state registered professional engineer or architect shall certify that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions above, and shall provide such certification to the Administrator as set forth in § 153.26 of this chapter.
(C) Enclosures. All new construction and substantial improvements that include fully enclosed areas formed by foundation and other exterior walls below the lowest floor that are subject to flooding, shall be designed to preclude finished living space and designed to allow for the entry and exit of flood waters to automatically equalize hydrostatic flood forces on exterior walls.
(1) Designs for complying with this requirement must either be certified by a state professional engineer or architect or meet or exceed the following minimum criteria:
(a) Provide 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;
(b) The bottom of all openings shall be no higher than one foot above the finished grade; and
(c) Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of flood waters in both directions.
(2) The enclosed area shall be the minimum necessary to allow for parking of vehicles, storage or building access.
(3) The interior portion of such enclosed area shall not be finished or partitioned into separate rooms in such a way as to impede the movement of flood waters and all such partitions shall comply with the provisions of this section.
(D) Standards for manufactured homes and recreational vehicles.
(1) All manufactured homes placed, or substantially improved, on:
(a) Individual lots or parcels;
(b) In expansions to existing manufactured home parks or subdivisions; or
(c) In new or substantially improved manufactured home parks or subdivisions, must meet all the requirements of new construction.
(2) All manufactured homes placed or substantially improved in an existing manufactured home park or subdivision must be elevated so that either:
(a) In AE Zones, with base flood elevations, the lowest floor of the manufactured home is elevated on a permanent foundation to no lower than one foot above the level of the base flood elevation; or
(b) In approximate A Zones, without base flood elevations, the manufactured home chassis is elevated and supported by reinforced piers (or other foundation elements of at least equivalent strength) that are at least three feet in height above the highest adjacent grade (as defined in § 153.05 of this chapter).
(3) Any manufactured home, which has incurred substantial damage as the result of a flood, must meet the standards of § 153.40 of this chapter and this section.
(4) All manufactured homes must be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
(5) All recreational vehicles placed in an identified special flood hazard area must either:
(a) Be on the site for fewer than 180 consecutive days;
(b) Be fully licensed and ready for highway use (a recreational vehicle is ready for highway use if it is licensed, on its wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices and has no permanently attached structures or additions); or
(c) The recreational vehicle must meet all the requirements for new construction.
(E) Standards for subdivisions and other proposed new development proposals. Subdivisions and other proposed new developments, including manufactured home parks, shall be reviewed to determine whether such proposals will be reasonably safe from flooding.
(1) All subdivision and other proposed new development proposals shall be consistent with the need to minimize flood damage.
(2) All subdivision and other proposed new development proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize or eliminate flood damage.
(3) All subdivision and other proposed new development proposals shall have adequate drainage provided to reduce exposure to flood hazards.
(4) In all approximate A Zones, it is required that all new subdivision proposals and other proposed developments (including proposals for manufactured home parks and subdivisions) greater than 50 lots or five acres, whichever is the lesser, include within such proposals base flood elevation data. (See § 153.44 of this chapter.)
(1994 Code, § 14-405) (Ord. 514, passed 8-8-1994; Ord. 703, passed 5-24-2010)