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In all areas of special flood hazard, where base flood elevation data has been provided as set forth in subsections 13-1-4B8, 13-1-5B or section 13-1-11 of this chapter, the following provisions are required:
A. Residential Construction: New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to, or above, the base flood elevation. A registered professional engineer, architect, or land surveyor shall submit a certification to the floodplain administrator that the standard of this subsection as proposed in subsection 13-1-6A of this chapter is satisfied.
B. Nonresidential Construction: New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to, or above, the base flood level or, together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is 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. A registered professional engineer or architect shall develop or review structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction are in accordance with accepted standards of practice as outlined in this subsection. A record of such certification which includes the specific elevation, in relation to mean sea level, to which such structures are floodproofed shall be maintained by the floodplain administrator.
C. Enclosures: New construction and substantial improvements, with fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and which 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 (2) 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;
2. The bottom of all openings shall be no higher than one foot (1') above grade;
3. Openings may be equipped with screens, louvers, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.
D. Manufactured Homes:
1. All manufactured homes to be placed within zone A on a community's FHBM or FIRM shall be installed using methods and practices which minimize flood damage. For the purpose of this requirement, manufactured homes must be elevated and anchored to resist flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over the top or frame ties to ground anchors. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.
2. Require that manufactured homes that are placed or substantially improved within zones A1-30, AH, and AE on the community's FIRM on sites located:
a. Outside of a manufactured home park or subdivision;
b. In a new manufactured home park or subdivision;
c. In an expansion to an existing manufactured home park or subdivision; or
d. In an existing manufactured home park or subdivision;
on which a manufactured home has incurred "substantial damage" as a result of a flood, be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
3. Require that manufactured homes be placed or substantially improved on sites in an existing manufactured home park, or a subdivision within zones A1-30, AH and AE on the community's FIRM that are not subject to the provisions of this subsection be elevated so that either:
a. The lowest floor of the manufactured home is at or above the base flood elevation; or
b. The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty six inches (36") in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
E. Recreational Vehicles:
1. Require that recreational vehicles placed on sites within zones A1-30, AH, and AE on the community's FIRM either:
a. Be on the site for fewer than one hundred eighty (180) consecutive days;
b. Be fully licensed and ready for highway use; or
c. Meet the permit requirements of subsection 13-1-6A of this chapter, and the elevation and anchoring requirements for manufactured homes in subsection D of this section.
2. A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions. (1985 Code § 12-417)