(§ 99-17 - § 99-20)

In all areas of special flood hazards the following standards are required:

A. Anchoring.

(1) All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.

(2) All manufactured homes shall be anchored to resist flotation, collapse or lateral movement. Methods of anchoring may include, but are not to be 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.

B. Construction materials and methods.

(1) All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

(2) All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

C. Utilities.

(1) All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;

(2) New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters;

(3) On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding; and

(4) Electrical, heating, ventilation, plumbing and air-conditioning equipment and other service facilities shall be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

D. Subdivision proposals.

(1) All subdivision proposals shall be consistent with the need to minimize flood damage;

(2) All subdivision proposals shall have public utilities and facilities, such as sewer, gas, electrical, and water systems, located and constructed to minimize flood damage;

(3) All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and

(4) Base flood elevation data shall be provided for subdivision proposals and other proposed developments which contain at least 50 lots or five acres (whichever is less).

E. Enclosure openings. All new construction and substantial improvements having 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 must meet or exceed the following minimum criteria: 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. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, or other covering or devices, provided that they permit the automatic entry and exit of floodwaters.

In all areas of special flood hazards where base flood elevation data have been provided as set forth in § 99-8, Basis for establishing areas of special flood hazard, or in § 99-15B, Use of other base flood data, the following standards are required:

A. Residential construction.

(1) In Zones A1-30 or AE Zones new construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above base flood elevation.

(2) Require within any AO zone on the municipality's FIRM that all new construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet (at least two feet if no depth number is specified), and, require adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.

B. Nonresidential construction. In A1-30 or AE all new construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the base flood elevation; or together with the attendant utilities and sanitary facilities, shall:

(1) Require within any AO zone on the municipality's FIRM that all new construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet (at least two feet if no depth number is specified), and, require adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures; or

(2) Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

(3) Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and

(4) 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 the applicable provisions of this subsection. Such certification shall be provided to the official as set forth in § 99-15C(2).

C. Manufactured homes.

(1) Manufactured homes shall be anchored in accordance with § 99-17A(2).

(2) All manufactured homes to be placed or substantially improved within an area of special flood hazard shall be elevated on a permanent foundation such that the top of the lowest floor is at or above the base flood elevation.

Coastal high-hazard areas (V or VE Zones) are located within the areas of special flood hazard established in § 99-8. These areas have special flood hazards associated with high velocity waters from tidal surges and hurricane wave wash; therefore, the following provisions shall apply:

A. Location of structures.

(1) All buildings or structures shall be located landward of the reach of the mean high tide.

(2) The placement of manufactured homes shall be prohibited, except in an existing manufactured home park or manufactured home subdivision.

B. Construction methods.

(1) Elevation. All new construction and substantial improvements shall be elevated on piling or columns so that the bottom of the lowest horizontal structural member of the lowest floor (excluding the piling or columns) is elevated to or above the base flood level, with all space below the lowest floor's supporting member open so as not to impede the flow of water, except for breakaway walls as provided for in Subsection B(4).

(2) Structural support.

(a) All new construction and substantial improvements shall be securely anchored on piling or columns.

(b) The pile or column foundation and structure attached thereto shall be anchored to resist flotation, collapse or lateral movement due to the effects of wind and water loading values each of which shall have a one-percent chance of being equaled or exceeded in any given year (one-hundred-year mean recurrence interval).

(c) There shall be no fill used for structural support.

(3) Certification. A registered professional engineer or architect shall develop or review the structural design specifications and plans for the construction and shall certify that the design and methods of construction to be used are in accordance with accepted standards of practice for compliance with the provisions of Subsection B(1) and (2)(a) and (b).

(4) Space below the lowest floor.

(a) Any alteration, repair, reconstruction or improvement to a structure started after the enactment of this ordinance shall not enclose the space below the lowest floor unless breakaway walls, open wood lattice-work or insect screening are used as provided for in this section.

(b) Breakaway walls, open wood lattice-work or insect screening shall be allowed below the base flood elevation, provided that they are intended to collapse under wind and water loads without causing collapse, displacement or other structural damage to the elevated portion of the building or supporting foundation system. Breakaway walls shall be designed for a safe loading resistance of not less than 10 and no more than 20 pounds per square foot. Use of breakaway walls which exceed a design safe loading of 20 pounds per square foot (either by design or when so required by local or state codes) may be permitted only if a registered professional engineer or architect certifies that the designs proposed meet the following conditions.

[1] Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; and

[2] The elevated portion of the building and supporting foundation system shall not be subject to collapse, displacement or other structural damage due to the effects of wind and water load acting simultaneously on all building components (structural and nonstructural). Water loading values used shall be those associated with the base flood. Wind loading values used shall be those required by applicable state or local building standards.

(c) If breakaway walls are utilized, such enclosed space shall be used solely for parking of vehicles, building access, or storage and not for human habitation.

(d) Prior to construction, plans for any breakaway wall must be submitted to the local administrator for approval.

C. Sand dunes. There shall be no alteration of sand dunes, which would increase potential flood damage.

A. When the Administrator has not yet identified any area within the municipality as having special flood-related erosion hazards, but the municipality has indicated the presence of such hazards by submitting an application to participate in the program, the municipality shall:

(1) Require an issuance of a permit for all proposed construction, or other development in the area of flood-related erosion hazard, as it is known to the municipality;

(2) Require review of each permit application to determine whether the proposed site alterations and improvements will be reasonably safe from flood-related erosion hazards or otherwise aggravate the existing flood-related erosion hazard; and

(3) If a proposed improvement is found to be in the path of flood-related erosion or to increase the erosion hazard, require the improvement to be relocated or adequate protective measures to be taken which will not aggravate the existing erosion hazard.

B. When the Administrator has delineated Zone E on the community's FIRM, the municipality shall:

(1) Meet the requirements of Subsection A; and

(2) Require a setback for all new development from the ocean, lake, bay, riverfront or other body of water, to create a safety buffer consisting of a natural vegetative or contour strip. This buffer will be designated by the Administrator according to the flood-related erosion hazard and erosion rate, in conjunction with the anticipated useful life of structures, and depending upon the geologic, hydrologic, topographic and climatic characteristics of the municipality's land. The buffer may be used for suitable purposes, such as for agricultural, forestry, outdoor recreation and wildlife habitat areas, and for other activities using temporary and portable structures.