a. New construction and substantial improvements of residential structures and manufactured homes within AO zones shall have the lowest floor (including basement and mechanical equipment) elevated above the highest adjacent grade to the structure, one foot or more above the depth number specified in feet on the community’s FIRM (at least two feet above the highest adjacent grade to the structure if no depth number is specified).

b. New construction and substantial improvements of nonresidential structures within AO zones shall either:

c. Require adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.

d. Recreational vehicles placed on sites within AO zones on the community’s FIRM either:

a. 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.

b. The bottom of all openings shall be no higher than one foot above grade.

c. 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. A garage attached to a residential structure, constructed with the garage floor slab below the BFE, must be designed to allow for the automatic entry and exit of floodwaters.

a. The interior grade is not more than two feet below the lowest adjacent exterior grade.

b. The height of the below grade crawlspace, as measured from the interior grade to the top of the crawlspace foundation wall, must not exceed four feet at any point.

c. There must be an adequate drainage system that removes interior floodwaters.

d. The velocity of floodwaters at the site should not exceed five feet per second for any crawlspace.

e. The building must be designed and adequately anchored to resist flotation, collapse, and lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

f. The crawlspace is an enclosed area below the BFE and, as such, must have openings that equalize hydrostatic pressures by allowing for the automatic entry and exit of floodwaters. The bottom of each flood vent opening can be no more than one foot above the lowest adjacent exterior grade.

g. Portions of the building below the BFE must be constructed with materials resistant to flood damage. This includes not only the foundation walls of the crawlspace used to elevate the building, but also any joists, insulation, or other materials that extend below the BFE.

h. Any building utility systems within the crawlspace must be elevated above BFE or designed so that floodwaters cannot enter or accumulate within the system components during flood conditions. Ductwork, in particular, must either be placed above the BFE or sealed from floodwaters.

a. In AE zones or other A zoned areas where the BFE has been determined or can be reasonably obtained:

b. If located in an AO zone, the structure shall meet the requirements in subsection (A)(1) of this section.

c. If located in an unnumbered A zone for which a BFE is not available and cannot be reasonably obtained, the structure shall be reasonably safe from flooding, but in all cases the lowest floor shall be at least two feet above the highest adjacent grade.

d. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or if used solely for parking, access or storage 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 must meet or exceed the following minimum criteria:

a. Be floodproofed so that below one foot or more above the base flood level the structure is watertight with walls substantially impermeable to the passage of water or dry floodproofed to the elevation required by ASCE 24, whichever is greater;

b. Have structural components capable of resisting hydrostatic and hydrostatic loads and effects of buoyancy;

c. Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this subsection based on their development and/or review of the structural design, specifications, and plans. Such certifications shall be provided to the official as set forth in CEMC Section 15.24.130(C)(2); and

d. Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection (A)(1) of this section.

a. Use of the appurtenant structure must be limited to parking of vehicles or limited storage;

b. The portions of the appurtenant structure located below the BFE must be built using flood resistant materials;

c. The appurtenant structure must be adequately anchored to prevent flotation, collapse, and lateral movement;

d. Any machinery or equipment servicing the appurtenant structure must be elevated or floodproofed to or above the BFE;

e. The appurtenant structure must comply with floodway encroachment provisions;

f. The appurtenant structure must be designed to allow for the automatic entry and exit of floodwaters;

g. The structure shall have low damage potential;

h. If the structure is converted to another use, it must be brought into full compliance with the standards governing such use; and

i. The structure shall not be used for human habitation.