In all special flood hazard areas where base flood elevation (BFE) data has been provided, as set forth in § 154.017-01, the following provisions, in addition to § 154.017-06, are required.
(A) Residential construction. New construction or substantial improvement of any residential structure (including manufactured homes) shall have the reference level, including basement, elevated no lower than the regulatory flood protection elevation, as defined in § 154.003-02.
(B) Non-residential construction.
(1) New construction or substantial improvement of any commercial, industrial, or other non-residential structure shall have the reference level, including basement, elevated no lower than the regulatory flood protection elevation, as defined in § 154.003-02.
(2) Structures located in A, AO, AE, and A1-30 Zones may be flood-proofed to the regulatory flood protection elevation in lieu of elevation; provided that all areas of the structure below the required flood protection elevation are water-tight with walls substantially impermeable to the passage of water, using structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy.
(3) A registered professional engineer or architect shall certify that the standards of this division are satisfied.
(4) Such certification shall be provided to the official as set forth in § 154.017-03, along with the operational and maintenance plans.
(C) Manufactured homes.
(1) New or replacement manufactured homes shall be elevated so that the reference level of the manufactured home is no lower than the regulatory flood protection elevation, as defined in § 154.003-02.
(2) Manufactured homes shall be securely anchored to an adequately anchored foundation to resist flotation, collapse, and lateral movement in accordance with the State of North Carolina Regulations for Manufactured/Mobile Homes, 1995 Edition, and any revision thereto adopted by the Commissioner of Insurance pursuant to G.S. § 143-143.15 or a certified engineered foundation. Additionally, when the elevation would be met by an elevation of the chassis 36 inches or less above the grade at the site, the chassis shall be supported by reinforced piers or engineered foundation. When the elevation of the chassis is above 36 inches in height, an engineering certification is required.
(3) All foundation enclosures or skirting shall be in accordance with division (D) below.
(4) An evacuation plan must be developed for evacuation of all residents of all new, substantially improved or substantially damaged manufactured home parks or subdivisions located within flood-prone areas. This plan shall be filed with and approved by the Floodplain Administrator and the local Emergency Management Coordinator.
(5) Elevated building. Enclosed areas, of new construction or substantially improved structures, which are below the regulatory flood protection elevation:
(a) Shall not be designed or used for human habitation, but shall only be used for parking of vehicles, building access or limited storage of maintenance equipment used in connection with the premises. Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment (standard exterior door), or entry to the living area (stairway or elevator). The interior portion of such enclosed area shall not be partitioned or finished into separate rooms, except to enclose storage areas;
(b) Shall be constructed entirely of flood resistant materials below the regulatory flood protection elevation; and
(c) Shall include, in Zones A, AO, AE, AH and A99, measures to automatically equalize hydrostatic flood forces on walls by allowing for the entry and exit of flood waters. To meet this requirement, the openings must either be certified by a professional engineer or architect or meet the following minimum design criteria:
1. Provide a minimum of two openings on different sides of each enclosed area subject to flooding;
2. The total net area of all openings must be at least one square inch for each square foot of enclosed area subject to flooding;
3. If a building has more than one enclosed area, each area must have openings to allow flood waters to automatically enter and exit;
4. The bottom of all required openings shall be no higher than one foot above the adjacent grade;
5. Openings may be equipped with screens, louvers or other opening coverings or devices; provided, they permit the automatic flow of flood waters in both directions; and
6. Foundation enclosures made of flexible skirting are not considered enclosures for regulatory purposes and, therefore, do not require openings. Masonry or wood underpinning, regardless of structural status, is considered an enclosure and requires openings as outlined above.
(D) Existing buildings and structures. For applications for building permits to improve buildings and structures, including alterations, movement, enlargement, replacement, repair, change of occupancy, additions, rehabilitations, renovations, substantial improvements, repairs of substantial damage, and any other improvement of or work on such buildings and structures, the Floodplain Administrator, in coordination with the Building Official, shall:
(1) Estimate the market value, or require the applicant to obtain an appraisal of the market value prepared by a qualified independent appraiser, of the building or structure before the start of construction of the proposed work; in the case of repair, the market value of the building or structure shall be the market value before the damage occurred and before any repairs are made;
(2) Compare the cost to perform the improvement, the cost to repair a damaged building to its pre-damaged condition, or the combined costs of improvements and repairs, if applicable, to the market value of the building or structure;
(3) Determine and document whether the proposed work constitutes substantial improvement or repair of substantial damage; and
(4) Notify the applicant if it is determined that the work constitutes substantial improvement or repair of substantial damage and that compliance with the flood resistant construction requirements of the N.C. Building Code and this chapter is required.
(E) Recreational vehicles. Recreational vehicles placed on sites within a special flood hazard area shall either:
(1) Be on site for fewer than 180 consecutive days and be fully licensed and ready for highway use (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 has no permanently attached additions); or
(2) Meet all the requirements for new construction, including anchoring and elevation requirements of division (C)(1) and (2) above and §§ 154.017-03 and 154.017-04.
(F) Temporary non-residential structures. Prior to the issuance of a floodplain development permit for a temporary structure, applicants must submit to the Floodplain Administrator a plan for the removal of such structure(s) in the event of a hurricane, flash flood or other type of flood warning notification. The following information shall be submitted in writing to the Floodplain Administrator for review and written approval:
(1) A specified time for which the temporary use will be permitted. Time specified should be minimal with total time on site not to exceed one year;
(2) The name, address, and phone number of the individual responsible for the removal of the temporary structure;
(3) The time frame prior to the event at which a structure will be removed (i.e., minimum of 72 hours before landfall of a hurricane or immediately upon flood warning notification);
(4) A copy of the contract or other suitable instrument with a trucking company to ensure the availability of removal equipment when needed; and
(5) Designation, accompanied by documentation of a location outside the special flood hazard area, to which the temporary structure will be moved.
(G) Accessory structures. When accessory structures (sheds, detached garages, and the like) are to be placed within a special flood hazard area, the following criteria shall be met:
(1) Accessory structures shall not be used for human habitation (including working, sleeping, living, cooking or restroom areas);
(2) Accessory structures shall not be temperature controlled;
(3) Accessory structures shall be designed to have low flood damage potential;
(4) Accessory structures shall be constructed and placed on the building site to offer the minimum resistance to the flow of flood waters;
(5) Accessory structures shall be firmly anchored in accordance with this section;
(6) All service facilities such as electrical shall be installed in accordance with this section;
(7) Openings to relieve hydrostatic pressure during a flood shall be provided below regulatory flood protection elevation in conformance with this section; and
(8) An accessory structure with a footprint less than 150 square feet or that is a minimal investment of $3,000 or less that satisfies the criteria outlined above does not require an elevation or flood-proofing certificate. Elevation or flood-proofing certifications are required for all other accessory structures in accordance with § 154.017-03.
(H) Tanks. When gas and liquid storage tanks are to be placed within a special flood hazard area, the following criteria shall be met:
(1) Underground tanks. Underground tanks in flood hazard areas shall be anchored to prevent flotation, collapse or lateral movement resulting from hydrodynamic and hydrostatic loads during conditions of the design flood, including the effects of buoyancy assuming the tank is empty;
(2) Above-ground tanks, elevated. Above-ground tanks in flood hazard areas shall be elevated to or above the regulatory flood protection elevation on a supporting structure that is designed to prevent flotation, collapse or lateral movement during conditions of the design flood. Tank-supporting structures shall meet the foundation requirements of the applicable flood hazard area;
(3) Above-ground tanks, not elevated. Above-ground tanks that do not meet the elevation requirements of this chapter shall be permitted in flood hazard areas provided the tanks are designed, constructed, installed, and anchored to resist all flood-related and other loads, including the effects of buoyancy, during conditions of the design flood and without release of contents in the floodwaters or infiltration by floodwaters into the tanks. Tanks shall be designed, constructed, installed, and anchored to resist the potential buoyant and other flood forces acting on an empty tank during design flood conditions; and
(4) Tank inlets and vents. Tank inlets, fill openings, outlets and vents shall be:
(a) At or above the regulatory flood protection elevation or fitted with covers designed to prevent the inflow of floodwater or outflow of the contents of the tanks during conditions of the design flood; and
(b) Anchored to prevent lateral movement resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy, during conditions of the design flood.
(I) Other development.
(1) Fences in regulated floodways and NEAs that have the potential to block the passage of floodwaters, such as stockade fences and wire mesh fences, shall meet the limitations of § 154.017-11.
(2) Retaining walls, sidewalks and driveways in regulated floodways and NEAs. Retaining walls and sidewalks and driveways that involve the placement of fill in regulated floodways shall meet the limitations of § 154.017-11.
(3) Roads and watercourse crossings in regulated floodways and NEAs. Roads and watercourse crossings, including roads, bridges, culverts, low-water crossings and similar means for vehicles or pedestrians to travel from one side of a watercourse to the other side, that encroach into regulated floodways shall meet the limitations of § 154.017-11.
(Ord. passed 4-17-2023)