In addition to the general standards, the following standards apply to specific development types in specific risk zones. Risk zones listed in this code that do not appear on the current FIRM are not applicable.
(A) In AE risk zones: special flood hazard areas with base floods determined.
(1) For residential structures in zone AE:
(a) For all new residential structures, the top surface of the lowest floor must have an elevation of two feet or more above the published BFE. This elevation must be documented on an elevation certificate properly completed by a professional engineer, surveyor or architect licensed to practice in the State of Arkansas.
(b) For all substantial improvements or substantial damage to existing residential structures, the entire structure becomes subject to the requirements of a new residential structure.
(c) For any reconstruction, rehabilitation, addition, or other improvement to an existing residential structure that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new residential structure.
(2) For nonresidential structures in zone AE:
(a) All new commercial, industrial or other nonresidential structures must either:
1. Have the lowest floor (including basement) elevated two feet or more above the base flood level; or
2. Be floodproofed such that, together with attendant utility and sanitary facilities, be designed so that below an elevation of three feet above 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.
3. A registered professional engineer or architect shall develop and/or review structural design, specifications, and plans for the construction, and shall certify on a floodproofing certificate that the design and methods of construction are in accordance with accepted standards of practice as outlined in this section. 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.
(b) For all substantial improvements or substantial damage to existing commercial, industrial or other nonresidential structures the entire structure becomes subject to the requirements of a new nonresidential structure.
(c) For any reconstruction, rehabilitation, addition, or other improvement to an existing nonresidential structure that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new nonresidential structure.
(3) For manufactured homes in zone AE:
(a) All manufactured homes that are placed or substantially improved on sites:
1. Outside of a manufactured home park or subdivision;
2. In a new manufactured home park or subdivision;
3. In an expansion to an existing manufactured home park or subdivision; or
4. 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 two feet or more above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement;
(b) Require that manufactured homes be placed or substantially improved on sites in an existing manufactured home park or subdivision on the community’s FIRM that are not subject to the provisions of division (A)(3)(a) of this section be elevated so that either:
1. The lowest floor of the manufactured home is two feet or more above the base flood elevation; or
2. The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement;
(c) For all substantial improvements or substantial damage to existing manufactured home, the entire structure becomes subject to the requirements of a new manufactured home;
(d) For any reconstruction, rehabilitation, addition, or other improvement to an existing manufactured home that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new manufactured home.
(4) Where FEMA has not established a regulatory floodway in zone AE, no floodplain development permit may be issued unless a detailed engineering analysis is submitted along with the application that demonstrates the increase in base floodwater elevation due to the proposed development and all cumulative developments since the publication of the current FIRM will be less than one foot.
(B) Floodways: high risk areas of stream channel and adjacent floodplain. Developments in regulatory floodways are prohibited, unless:
(1) A no-rise certificate, signed and stamped by a professional engineer licensed to practice in the State of Arkansas, is submitted to demonstrate through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed development would not result in any increase in flood levels within the community during the occurrence of a base flood event; or
(2) All requirements of 44 CFR § 65.12 are first met.
(C) In AH or AO risk zones: special flood hazard areas of shallow flooding.
(1) For residential structures in zones AH or AO:
(a) All new residential structures must be constructed with the top surface of the lowest floor elevated two feet or more above the published BFE, or two feet or more above the highest adjacent grade in addition to the depth number specified (at least two feet if no depth number is specified) on the community’s FIRM. This elevation must be documented on an elevation certificate properly completed by a professional engineer, surveyor or architect licensed to practice in the State of Arkansas.
(b) For all substantial improvements or substantial damage to existing residential structures the entire structure becomes subject to the requirements of a new residential structure.
(c) For any reconstruction, rehabilitation, addition, or other improvement to an existing residential structure that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new residential structure.
(2) For nonresidential structures in zones AH or AO:
(a) All new commercial, industrial or other nonresidential structure must either:
1. Have the top surface of the lowest floor elevated two feet or more above the published BFE, or two feet or more above the highest adjacent grade in addition to the depth number specified (at least two feet if no depth number is specified) on the community’s FIRM, with documentation on an elevation certificate properly completed by a professional engineer, surveyor or architect licensed to practice in the State of Arkansas; or
2. Be floodproofed such that the structure, together with attendant utility and sanitary facilities be designed so that below three feet or more above the published BFE in zone AH, or three feet or more above the base specified flood depth in an AO zone, 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 of effects of buoyancy.
(b) For all substantial improvements or substantial damage to existing commercial, industrial or other nonresidential structures the entire structure becomes subject to the requirements of a new nonresidential structure.
(c) For any reconstruction, rehabilitation, addition, or other improvement to an existing nonresidential structure that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new nonresidential structure.
(3) For manufactured homes in zones AH or AO:
(a) All manufactured homes that are placed or substantially improved on sites:
1. Outside of a manufactured home park or subdivision;
2. In a new manufactured home park or subdivision;
3. In an expansion to an existing manufactured home park or subdivision; or
4. 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 two feet or more above the published BFE, or two feet or more above the highest adjacent grade in addition to the depth number specified (at least two feet if no depth number is specified) on the community’s FIRM, and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
(b) Require that manufactured homes be placed or substantially improved on sites in an existing manufactured home park or subdivision on the community’s FIRM that are not subject to the provisions of division (C)(3)(a) of this section be elevated so that either:
1. The lowest floor of the manufactured home meets the elevation standard of division (C)(3)(a); or
2. The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
(c) For all substantial improvements or substantial damage to existing manufactured home, the entire structure becomes subject to the requirements of a new manufactured home.
(d) For any reconstruction, rehabilitation, addition, or other improvement to an existing manufactured home that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new manufactured home.
(4) Where FEMA has not established a regulatory floodway in zones AH or AO, no floodplain development permit may be issued unless a detailed engineering analysis is submitted along with the application that demonstrates the increase in base floodwater elevation due to the proposed development and all cumulative developments since the publication of the current FIRM will be less than one foot.
(5) Require adequate drainage paths around structures on slopes, to guide flood waters around and away from proposed structures.
(D) In A risk zones: special flood hazard areas with no base flood elevations determined.
(1) In zone A, the applicant or the applicant’s agent must determine a base flood elevation prior to construction. The BFE will be based on a source or method approved by the local Floodplain Administrator.
(2) For residential structures in zone A.
(a) For all new residential structures, the top surface of the lowest floor must have an elevation two feet or more above the BFE. This elevation must be documented on an elevation certificate properly completed by a professional engineer, surveyor or architect licensed to practice in the State of Arkansas.
(b) For all substantial improvements or substantial damage to existing residential structures, the entire structure becomes subject to the requirements of a new residential structure.
(c) For any reconstruction, rehabilitation, addition, or other improvement to an existing residential structure that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new residential structure.
(3) For nonresidential structures in zone A.
(a) All new commercial, industrial or other nonresidential structures must either:
1. Have the lowest floor (including basement) elevated two feet or more above the base flood level; or
2. Be floodproofed such that, together with attendant utility and sanitary facilities, be designed so that below an elevation of three feet above 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.
3. A registered professional engineer or architect shall develop and/or review structural design, specifications, and plans for the construction, and shall certify on a floodproofing certificate that the design and methods of construction are in accordance with accepted standards of practice as outlined in this section. 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.
(b) For all substantial improvements or substantial damage to existing commercial, industrial or other nonresidential structures the entire structure becomes subject to the requirements of a new nonresidential structure.
(c) For any reconstruction, rehabilitation, addition, or other improvement to an existing nonresidential structure that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new nonresidential structure.
(4) For manufactured homes in zone A.
(a) All manufactured homes that are placed or substantially improved on sites:
1. Outside of a manufactured home park or subdivision;
2. In a new manufactured home park or subdivision;
3. In an expansion to an existing manufactured home park or subdivision; or
4. 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 two feet or more above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
(b) Require that manufactured homes be placed or substantially improved on sites in an existing manufactured home park or subdivision on the community’s FIRM that are not subject to the provisions of division (D)(4)(a) of this section be elevated so that either:
1. The lowest floor of the manufactured home is two feet or more above the base flood elevation; or
2. The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
(c) For all substantial improvements or substantial damage to existing manufactured home, the entire structure becomes subject to the requirements of a new manufactured home.
(d) For any reconstruction, rehabilitation, addition, or other improvement to an existing manufactured home that is less than a substantial improvement, only the improved area, but not the entire structure, becomes subject to the requirements of a new manufactured home.
(5) Base flood elevation data and a regulatory floodway, utilizing accepted engineering practices, shall be generated for subdivision proposals and other proposed development including the placement of manufactured home parks and subdivisions which is greater than 50 lots or five acres, whichever is lesser, if not otherwise provided.
(Ord. 417, passed 1-20-09)