In all SFHAs, the following provisions are required:
(A) In addition to the requirements of § 152.045, all structures to be located in the SFHA shall be protected from flood damage below the FPG. This building protection requirement applies to the following situations:
(1) Construction or placement of any new structure having a floor area greater than 400 square
feet;
(2) Addition or improvement made to any existing structure:
(a) Where the cost of the addition or improvement equals or exceeds 50% of the value of the existing structure (excluding the value of the land);
(b) With a previous addition or improvement constructed since the community's first floodplain chapter.
(3) Reconstruction or repairs made to a damaged structure where the costs of restoring the structure to its before damaged condition equals or exceeds 50% of the market value of the structure (excluding the value of the land) before damage occurred;
(4) Installing a travel trailer or recreational vehicle on a site for more than 180 days;
(5) Installing a manufactured home on a new site or a new manufactured home on an existing
site. This chapter does not apply to returning the existing manufactured home to the same site it lawfully occupied before it was removed to avoid flood damage; and
(6) Reconstruction or repairs made to a repetitive loss structure.
(B) Residential construction. New construction or substantial improvement of any residential structure (or manufactured home) shall have the lowest floor; including basement, at or above the FPG (2 feet above the base flood elevation). Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with the standards of § 152.046(D).
(C) Non-Residential construction. New construction or substantial improvement of any commercial, industrial, or non-residential structure (or manufactured home) shall either have the lowest floor, including basement, elevated to or above the FPG (2 feet above the base flood elevation) or be floodproofed to or above the FPG. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with the standards of § 152.046(D). Structures located in all A Zones may be floodproofed in lieu of being elevated if done in accordance with the following:
(1) A registered professional engineer or architect shall certify that the structure has been designed so that below the FPG, the structure and attendant utility facilities are watertight and capable of resisting the effects of the regulatory flood. The structure design shall take into account flood velocities, duration, rate of rise, hydrostatic pressures, and impacts from debris or ice. The certification shall be provided to the official as set forth in § 152.032(B)(10).
(2) Floodproofing measures shall be operable without human intervention and without an outside source of electricity.
(D) Elevated structures. New construction or substantial improvements of elevated structures shall have the lowest floor at or above the FPG. Elevated structures with fully enclosed areas formed by foundation and other exterior walls below the flood protection grade shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls. Designs must meet the following minimum criteria:
(1) Provide a minimum of 2 openings located in a minimum of 2 exterior walls (having a total net area of not less than 1 square inch for every 1 square foot of enclosed area);
(2) The bottom of all openings shall be no more than 1 foot above the exterior grade or the interior grade immediately beneath each opening, whichever is higher;
(3) Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions;
(4) Openings are to be not less than 3 inches in any direction in the plane of the wall. This requirement applies to the hole in the wall, excluding any device that may be inserted such as typical foundation air vent device;
(5) Access to the enclosed area shall be the minimum necessary to allow for parking for vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standard exterior door) or entry to the living area (stairway or elevator);
(6) The interior portion of the enclosed area shall not be partitioned or finished into separate rooms;
(7) The interior grade of the enclosed area shall be at an elevation at or higher than the exterior grade; and
(8) Where elevation requirements exceed 6 feet above the highest adjacent grade, a copy of the
legally recorded deed restriction prohibiting the conversion of the area below the lowest floor to a use or dimension contrary to the structure's originally approved design, shall be presented as a condition of issuance of the final certificate of occupancy.
(E) Structures constructed on fill. A residential or nonresidential structure may be constructed on a permanent land fill in accordance with the following:
(1) The fill shall be placed in layers no greater than 1 foot deep before compacting to 95% of the maximum density obtainable with either the standard or modified proctor test method.
(2) The fill should extend at least 10 feet beyond the foundation of the structure before sloping below the FPG.
(3) The fill shall be protected against erosion and scour during flooding by vegetative cover, riprap, or bulkheading. If vegetative cover is used, the slopes shall be no steeper than 3 horizontal to 1 vertical.
(4) The fill shall not adversely affect the flow of surface drainage from or onto neighboring properties.
(5) The top of the lowest floor including basements shall be at or above the FPG.
(F) Standards for manufactured homes and recreational vehicles. Manufactured homes and recreational vehicles to be installed or substantially improved on a site for more than 180 days must meet one of the following requirements:
(1) The manufactured home shall be elevated on a permanent foundation such that the lowest floor shall be at or above the FPG and securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement. This requirement applies to all manufactured homes to be placed on a site;
(a) Outside a manufactured home park or subdivision;
(b) In a new manufactured home park or subdivision;
(c) In an expansion to an existing manufactured home park or subdivision; or
(d) In an existing manufactured home park or subdivision on which a manufactured home has incurred substantial damage as a result of a flood.
(2) The manufactured home shall be elevated so that the lowest floor of the manufactured home chassis is supported by reinforced piers or other foundation elevations 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. This requirement applies to all manufactured homes to be placed on a site in an existing manufactured home park or subdivision that has not been substantially damaged by a flood.
(3) Manufactured homes with fully enclosed areas formed by foundation and other exterior walls below the flood protection grade shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls as required for elevated structures in § 152.046(D).
(4) Flexible skirting and rigid skirting not attached to the frame or foundation of a manufactured home are not required to have openings.
(5) Recreational vehicles placed on a site shall either:
(a) Be on site for less than 180 days; and
(b) Be fully licensed and ready for highway use (defined as being on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions); or
(c) Meet the requirements for manufactured homes as stated earlier in this section.
(Ord. 01-17-2011, passed 1-17-2012)