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In all SFHAs, the following provisions are required:
(A) In addition to the requirements of § 155.40, 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); or
(b) With a previous addition or improvement constructed since the community’s first floodplain ordinance.
(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.
(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 (two 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 flood waters shall be provided in accordance with the standards of division (D) of this section.
(C) Nonresidential construction. New construction or substantial improvement of any commercial, industrial, or nonresidential structure (or manufactured home) shall either have the lowest floor, including basement, elevated to or above the FPG (two 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 flood waters shall be provided in accordance with the standards of division (D) of this section. 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. Such certification shall be provided to the official as set forth in § 155.32(J).
(2) Floodproofing measures shall be operable without human intervention and without an outside source of electricity.
(D) Elevated structures. New construction, reconstruction, or substantial improvements of elevated structures that include fully enclosed areas formed by foundation and other exterior walls below the FPG shall be designed to preclude finished living space and designed to allow for the entry and exit of flood waters to automatically equalize hydrostatic flood forces on exterior walls. Designs must meet the following minimum criteria:
(1) Provide a minimum of two openings located in a minimum of two exterior walls (having a total net area of not less than one square inch for every one square foot of enclosed area; and
(2) All openings shall be located entirely below the FPG; and
(3) The bottom of all openings shall be no more than one foot above the foundation interior grade (which must be equal to in elevation or high than the exterior foundation grade); and
(4) Openings may be equipped with screens, louvers, valves or other coverings or devices, provided they permit the automatic flow of flood waters in both directions; and
(5) Openings are to be not less than three 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; and
(6) 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); and
(7) The interior portion of such enclosed area shall not be partitioned or finished into separate rooms; and
(8) Where elevation requirements exceed six 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) Standards for structures constructed with a crawlspace. A residential or nonresidential structure may be constructed with a crawlspace located below the FPG provided that the following conditions are met:
(1) The building must be designed and adequately anchored to resist flotation, collapse, and lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy; and
(2) Any enclosed area below the FPG shall have openings that equalize hydrostatic pressures by allowing for the automatic entry and exit of flood waters. Designs for complying with this requirement must either be certified by a professional engineer or architect or meet the following minimum criteria:
(a) Provide a minimum of two openings in a minimum of two exterior walls having a total net area of not less than one square inch for every one square foot of enclosed area; and
(b) The bottom of all openings shall be no higher than one foot above foundation interior grade (which must be equal to in elevation or higher than the exterior foundation grade); and
(c) Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of flood waters in both directions; and
(3) Utility systems within the crawlspace must be elevated above the FPG; and
(4) The interior height of the crawlspace measured from the interior grade of the crawlspace to the top of the foundation wall must not exceed four feet at any point; and
(5) An adequate drainage system must be installed to remove flood waters from the interior area of the crawlspace within a reasonable period of time after a flood event; and
(6) Portions of the building below the FPG must be constructed with materials resistant to flood damage; and
(7) The interior grade of the crawlspace must be at or above the base flood elevation.
(F) Standards for structures constructed on filled stem wall foundation. A residential or nonresidential structure may be constructed on filled stem wall foundation (filled chain wall foundation) provided the following conditions are met:
(1) The solid perimeter foundation wall is backfilled with compacted structural fill to adequately support a slab floor; and
(2) The top of the lowest floor shall be at or above the FPG.
(G) 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 one foot deep before compacting to 95% of the maximum density obtainable with the either the Standard or Modified Proctor Test method; and
(2) The fill should extend at least ten feet beyond the foundation of the structure before sloping below the FPG; and
(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; and
(4) The fill shall not adversely affect the flow of surface drainage from or onto neighboring properties; and
(D) Base flood elevation data shall be provided for subdivision proposals and other proposed development (including manufactured home parks and subdivisions), which is greater than the lesser of 50 lots or five acres.
(E) All subdivision proposals shall minimize development in the SFHA and/or limit density of development permitted in the SFHA.
(F) All subdivision proposals shall ensure safe access into/out of SFHA for pedestrians and vehicles (especially emergency responders).
(Ord. 2010-10, passed 12-7-10)