(A) Permitted uses.
(1) Permitted uses shall be those uses of land or structures listed as permitted uses in the underlying zoning district(s). If no preexisting, underlying zoning districts exist, then any residential or nonresidential structure or use of a structure or land shall be a permitted use in the Flood Fringe District, provided the use does not constitute a public nuisance.
(2)
All permitted uses shall comply with the standards for flood fringe permitted uses listed in subsection (B) of this section and the standards for all flood fringe uses listed in subsection (E) of this section.
(B) Standards for flood fringe permitted uses.
(1)
All structures, including accessory structures, must be elevated on fill so that the lowest floor, including the basement floor, is at or above the regulatory flood protection elevation or must adhere to the alternative listed in subsection (B)(2) of this section.
(a) The finished fill elevation for structures shall be no lower than one foot below the regulatory flood protection elevation. The fill for residential structures shall extend at the same elevation at least 15 feet beyond the outside limits of the structure erected thereon.
(2) As an alternative to elevation on fill, enclosed accessory structures that constitute a minimal investment and that do not exceed 576 square feet in size may be floodproofed in accordance with the following standards:
(a) Accessory structures shall only be used for parking and storage.
(b) Accessory structures must allow for the equalization of hydrostatic pressure by accommodating for the inundation of floodwaters. There must be a minimum of two openings in the outside walls of the structure, having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding. There must be openings on at least two sides of the structure, and the bottom of all openings must be no higher than one foot above the lowest adjacent grade to the structure. The openings shall allow automatic entry and exit of floodwaters without human intervention.
(3)
The cumulative placement of fill where at any one time in excess of 1,000 cubic yards of fill is located on the parcel shall be allowable only as a conditional use, unless the fill is specifically intended to elevate a structure in accordance with subsection (B)(1) of this section.
(4) All fill must be properly compacted and the slopes must be properly protected by the use of riprap, vegetative cover, or other acceptable method.
(5) All new principal structures must have vehicular access at or above an elevation no more than two feet below the regulatory flood protection elevation, or must have a flood warning/emergency evacuation plan acceptable to the city.
(6) Accessory uses such as yards, railroad tracks, and parking lots may be at an elevation lower than the regulatory flood protection elevation. However, any facilities used by employees or the general public must be designed with a flood warning system that provides adequate time for evacuation if the area is inundated to a depth and velocity such that the depth multiplied by the velocity would exceed a product of four upon occurrence of the regional flood.
(7)
The provisions of subsection (E) of this section shall apply.
(C) Conditional uses.
(1) The placement of floodproofed nonresidential basements below the regulatory flood protection elevation.
(2) The cumulative placement of more than 1,000 cubic yards of fill when the fill is not being used to elevate a structure in accordance with subsection (B)(1) of this section.
(3) The use of methods other than the fill standards in subsection (B)(1) of this section to elevate the lowest floor above the regulatory flood protection elevation.
(D) Standards for flood fringe conditional uses.
(1) Alternative elevation methods. Alternative elevation methods other than the use of fill may be utilized to elevate a structure’s lowest floor above the regulatory flood protection elevation. These alternative methods may include the use of stilts, pilings, filled stem walls, parallel walls and the like, or internally-flooded, enclosed areas such as crawl spaces, attached garages, or tuck-under garages. The base or floor of an enclosed area shall be considered above-grade, and not a structure’s basement or lowest floor, if:
(a) The enclosed area is above-grade on at least one side of the structure;
(b) It is designed to internally flood; and
(c) It is used solely for parking of vehicles, building access or storage. The above-noted alternative elevation methods are subject to the following additional standards:
1. Internally-flooded, fully enclosed areas, such as crawl spaces or tuck-under garages, must be designed to internally flood and include a minimum of two openings on at least two sides of the structure. The bottom of all openings shall be no higher than one foot above grade, and have a minimum net area of not less than one square inch for every square foot of enclosed area subject to flooding unless a registered professional engineer or architect certifies that a smaller net area would suffice.
2. Floodproofing certifications consistent with § 151.03.39 shall be required. The structure shall be subject to a deed-restricted nonconversion agreement with the issuance of any permit.
(a) Residential basement construction shall not be allowed below the regulatory flood protection elevation.
(b) Nonresidential basements may be allowed below the regulatory flood protection elevation, provided the basement is structurally dry floodproofed in accordance with this part.
(3) Dry floodproofing. All areas of nonresidential structures, including basements, to be placed below the regulatory flood protection elevation shall be floodproofed in accordance with the structurally dry floodproofing classifications in the State Building Code. Structurally dry floodproofing must meet the FP-1 or FP-2 floodproofing classification in the State Building Code, and this shall require making the structure watertight, with the walls substantially impermeable to the passage of water, and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. Structures floodproofed to the FP-3 or FP-4 classification shall not be permitted.
(4) Erosion/sedimentation control plan. When at any one time more than 1,000 cubic yards of fill or other similar material is located on a parcel for the activities as on-site storage, landscaping, sand and gravel operations, landfills, roads, dredge spoil disposal or construction of flood control works, an erosion/sedimentation control plan must be submitted unless the community is enforcing a state-approved shoreland management ordinance.
(5) Storage of materials and equipment.
(a) The storage or processing of materials that are, in time of flooding, flammable, explosive, or potentially injurious to human, animal or plant life is prohibited.
(b) Storage of other materials or equipment may be allowed if readily removable from the area within the time available after a flood warning and in accordance with a plan approved by the governing body.
(6)
The provisions of subsection (E) of this section shall also apply.
(E) Standards for all flood fringe uses.
(1) Vehicular access. All new principal structures must have vehicular access at or above an elevation not more than two feet below the regulatory flood protection elevation. If a variance to this requirement is granted, the Planning Commission must specify limitations on the period of use or occupancy of the structure for times of flooding, and only after determining that adequate flood warning time and local flood emergency response procedures exist.
(2) Commercial uses. Accessory land uses, such as yards, railroad tracks and parking lots, may be at elevations lower than the regulatory flood protection elevation. However, a permit for the facilities to be used by the employees or the general public shall not be granted in the absence of a flood warning system that provides adequate time for evacuation if the area would be inundated to a depth and velocity such that, when multiplying the depth (in feet) times velocity (in feet per second), the product number exceeds four upon occurrence of the regional flood.
(3) Manufacturing and industrial uses. Measures shall be taken to minimize interference with normal plant operations, especially along streams having protracted flood durations. Certain accessory land uses, such as yards and parking lots, may be at lower elevations subject to requirements set out in subsection (B) of this section. In considering permit applications, due consideration shall be given to needs of an industry whose business requires that it be located in floodplain areas.
(4) Fill compaction and side slope protection standards. Fill shall be properly compacted and the slopes shall be properly protected by the use of riprap, vegetative cover or other acceptable method. The Federal Emergency Agency (FEMA) has established criteria for removing the special flood hazard area designation for certain structures properly elevated on fill above the regional flood elevation. FEMA’s requirements incorporate specific fill compaction and side slope protection standards for multi-structure or multi-lot developments. These standards should be investigated prior to the initiation of site preparation if a change of special flood hazard area designation will be requested.
(Ord. 20220120-01, passed 1-20-22)