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In all areas of special flood hazard, the following provisions are required for all new construction and substantial improvements.
(A) All new construction or substantial improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.
(B) All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage.
(C) All new construction or substantial improvements shall be constructed with materials resistant to flood damage.
(D) All new construction or substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering and accumulating within the components during conditions of flooding.
(E) All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system.
(F) 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.
(G) On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(H) All new construction or any substantial improvement located in a non-special flood hazard shall be constructed at seven feet mean sea level or 18 inches above the curb of the street, whichever is greater.
(1998 Code, § 58-81) (Ord. 08-16, passed 5-7-2008)
(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 division (A), as proposed in § 157.26(A)(1) of this chapter, is satisfied.
(B) Non-residential construction. New construction and substantial improvements of any commercial, industrial or other non-residential 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 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 develop and/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 division (B). 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 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.
(2) The bottom of all openings shall be no higher than one foot 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 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) All manufactured homes shall be in compliance with division (D)(1) above.
(3) All manufactured homes to be placed or substantially improved within Zones A1-30, AH and AE on the community’s FIRM shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the base flood elevation, and shall be securely anchored to an adequately anchored foundation system in accordance with the provisions of this division (D).
(1998 Code, § 58-82)
(C) Base flood elevation data shall be generated for subdivision proposals and other proposed developments, including manufactured home parks and subdivisions, which are greater than 50 lots or five acres, whichever is lesser, if not otherwise provided pursuant to §§ 157.07 or 157.25(B)(8) of this chapter.
(D) All subdivision proposals, including manufactured home parks and subdivisions, shall have adequate drainage provided to reduce exposure to flood hazards.
(E) All subdivision proposals, including manufactured home parks and subdivisions, shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize or eliminate flood damage.
(1998 Code, § 58-83)
(A) Located within the areas of special flood hazard established in § 157.07 of this chapter are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one to three feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and where velocity flow may be evident.
(B) Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply.
(1) All new construction and substantial improvements of residential structures shall have the lowest floor, including basement, elevated to seven feet mean sea level or 18 inches above the curb of the street; or above the highest adjacent grade at least as high as the depth number specified in feet on the community’s FIRM (at least two feet if no depth number is specified).
(2) All new construction and substantial improvements of non-residential structures shall:
(a) Have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community’s FIRM (at least two feet if no depth number is specified); or
(b) Together with attendant utility and sanitary facilities, be designed so that below the base flood level 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 or effects of buoyancy.
(3) A registered professional engineer or architect shall submit a certification to the Floodplain Administrator that the standards of this section, as proposed in § 157.26(A)(1) of this chapter, are satisfied.
(4) Within Zones AH and AO, adequate drainage paths shall be required around structures on slopes, to guide floodwaters around and away from proposed structures.
(1998 Code, § 58-84) (Ord. 08-16, passed 5-7-2008)
(A) Located within the areas of special flood hazard established in § 157.07 of this chapter are areas designated as floodways.
(B) Since the floodway is an extremely hazardous area due to the velocity of floodwater, which carries debris and potential projectiles and has erosion potential, the following provisions shall apply.
(1) Encroachments are prohibited, including fill, new construction, substantial improvements and other development, unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels within the community during the occurrence of the base flood discharge.
(2) If division (B)(1) above is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this subchapter.
(1998 Code, § 58-85)
(A) Located within the areas of special flood hazard established in § 157.07 of this chapter are areas designated as coastal high-hazard areas (Zones V1-30, VE and/or V).
(B) These areas have special flood hazards associated with high-velocity waters from tidal surges and hurricane wave wash; therefore, in addition to meeting all provisions outlined in this subchapter, the following provisions also apply.
(1) The elevation (in relation to mean sea level) of the bottom of the lowest structural member of the lowest floor (excluding pilings and columns) of all new and substantially improved structures shall be obtained, and whether or not such structures contain a basement. The Floodplain Administrator shall maintain a record of all such information.
(2) All new construction shall be located landward of the reach of mean high tide.
(3) (a) All new construction and substantial improvements shall be elevated on pilings and columns so that:
1. The bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated to or above the base flood level; and
2. The pile or column foundation and structure attached thereto is anchored to resist flotation, collapse and lateral movement due to the effects of wind and water loads acting simultaneously on all building components. Wind and water loading values shall each have a 1% chance of being equaled or exceeded in any given year (100-year mean recurrence interval).
(b) 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 meeting the provisions of this division (B)(3).
(4) All new construction and substantial improvements shall have the space below the lowest floor either free of obstruction or constructed with non-supporting breakaway walls, open wood latticework or insect screening intended to collapse under wind or water loads without causing collapse, displacement or other structural damage to the elevated portion of the building or the supporting foundation system. For the purpose of this section, a breakaway wall shall have a design safe loading resistance of not less than ten and not more than 20 pounds per square foot. Use of breakaway walls which exceed a design safe loading resistance 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:
(a) Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; and
(b) 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 loads acting simultaneously on all building components (structural and non-structural). Maximum wind and water loading values to be used in this determination shall each have a 1% chance of being equaled or exceeded in any given year (100-year mean recurrence interval).
(5) If breakaway walls are utilized, such enclosed space shall be useable solely for parking of vehicles, building access or storage. Such space shall not be used for human habitation.
(6) The use of fill for structural support of buildings is prohibited.
(7) Human-made alteration of sand dunes and mangrove stands which would increase potential flood damage is prohibited.
(1998 Code, § 58-86)