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Located within the areas of special flood hazard (Zones A and V) established in § 156.030 are small streams where no base flood data has been provided and where no floodways have been identified. The following provisions apply within such areas:
(A) In all areas of special flood hazard where base flood elevation data are not available, the applicant shall provide a hydrologic and hydraulic engineering analysis that generates base flood elevations for all subdivision proposals and other proposed developments containing at least 50 lots or five (5) acres, whichever is less;
(B) No encroachments, including fill, new construction, substantial improvements and new development, shall be permitted within 100 feet of the stream bank unless certification with supporting technical data by a registered and professional engineer is provided demonstrating that such encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.
(C) If § 156.067(A) is satisfied and base flood elevation data is available from other sources, all new construction and substantial improvements within such areas shall comply with all applicable flood hazard provisions of §§ 156.065 and 156.066 and shall be elevated or floodproofed in accordance with elevations established in § 156.069(K).
(D) Data from preliminary, draft, and final flood insurance studies constitutes best available data. Refer to FEMA Floodplain Management Technical Bulletin 1-98, Use of Flood Insurance Study (FIS) Data as Available Data. If an appeal is pending on the study in accordance with 44 CFR Ch. 1, Part 67.5 and 67.6, the data does not have to be used.
(E) When BFE data is not available from a federal, state, or other source, one (1) of the following methods may be used to determine a BFE. For further information regarding the methods for determining BFEs listed below, refer to FEMA’s manual, Managing Floodplain Development in Approximate Zone A Areas:
(1) Contour interpolation.
(a) Superimpose approximate Zone A boundaries onto a topographic map and estimate a BFE; or
(b) Add one-half (1/2) of the contour interval of the topographic map that is used to the BFE.
(2) Data extrapolation. A BFE can be determined if a site within 500 feet upstream of a reach of a stream reach for which a 100-year profile has been computed by detailed methods, and the floodplain and channel bottom slope characteristics are relatively similar to the downstream reaches. No hydraulic structures shall be present.
(3) Hydrologic and hydraulic calculations. Perform hydrologic and hydraulic calculations to determine BFEs using FEMA- approved methods and software.
(1985 Code, Ch. 15, Art. V) (Am. Ord. --, passed 4-27-2018)
Along rivers and streams where base flood elevation (BFE) data is provided but no floodway is identified for a special flood hazard area on the FIRM or in the FIS, no encroachments, including fill, new construction, substantial improvements, or other development, shall be permitted unless a certification with supporting technical data provided by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one (1) foot at any point within the community.
(1985 Code, Ch. 15, Art. V) (Am. Ord. --, passed 4-27-2018)
Located within the areas of special flood hazard established in § 156.030 are areas designated as shallow flooding. The following provisions shall apply within such areas:
(A) All new construction and substantial improvements of residential structures shall have the lowest floor elevated to at least as high as the depth number specified on the flood insurance rate map, in feet, above the highest adjacent grade. If no depth number is specified, the lowest floor shall be elevated at least three (3) feet above the highest adjacent grade.
(B) All new construction and substantial improvements of non-residential structures shall:
(1) Have the lowest floor elevated to at least as high as the depth number specified on the flood insurance rate map, in feet, above the highest adjacent grade. If no depth number is specified, the lowest floor shall be elevated at least three (3) feet above the highest adjacent grade; or
(2) Be completely floodproofed together with attendant utility and sanitary facilities to or above that level so that any space below that level 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. Certification is required as stated in § 156.052(K).
(C) All structures on slopes must have drainage paths around them to guide water away from the structures.
(1985 Code, Ch. 15, Art. V) (Am. Ord. --, passed 4-27-2018)
VARIANCE PROCEDURES
Variances may be issued for the repair or rehabilitation of historic structures upon the determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as a historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure.
(Ord. --, passed 4-27-2018)
Variances may be issued for development necessary for the conduct of a functionally dependent use provided the criteria of this chapter are met, no reasonable alternatives exist, and the development is protected by methods that minimize flood damage and create no additional threat to public safety.
(Ord. --, passed 4-27-2018)
Variances may be issued to wet floodproof an agricultural structure provided it is used solely for agricultural purposes. In order to minimize flood damages during the base flood and the threat to public health and safety, the structure must meet all of the conditions and considerations of § 156.087, this section, and the following standards:
(A) Use of the structure must be limited to agricultural purposes as listed below:
(1) Pole frame buildings with open or closed sides used exclusively for the storage of farm machinery and equipment;
(2) Steel grain bins and steel frame corncribs;
(3) General-purpose barns for the temporary feeding of livestock that are open on at least one (1) side;
(4) For livestock confinement buildings, poultry houses, dairy operations, and similar livestock operations, variances may not be issued for structures that were substantially damaged. New construction or substantial improvement of such structures must meet the elevation requirements of § 156.066(B).
(B) The agricultural structure must be built or, in the case of an existing building that is substantially damaged, rebuilt with flood-resistant materials for the exterior and interior building components and elements below the base flood elevation.
(C) The agricultural structure must be adequately anchored to prevent flotation, collapse, or lateral movement. All of the structure’s components must be capable of resisting specific flood-related forces, including hydrostatic, buoyant, hydrodynamic, and debris impact forces. Where flood velocities exceed five (5) feet per second, fast-flowing floodwaters can exert considerable pressure on the building’s enclosure walls or foundation walls.
(D) The agricultural structure must meet the ventilation requirement of § 156.066(D).
(E) Any mechanical, electrical, or other utility equipment must be located above the BFE plus any required freeboard or be contained within a watertight, floodproofed enclosure that is capable of resisting damage during flood conditions in accordance with § 156.065(E).
(F) The agricultural structure must comply with the floodway encroachment provisions of § 156.066(E).
(G) Major equipment, machinery, or other contents must be protected. Such protection may include protective watertight floodproofed areas within the building, the use of equipment hoists for readily elevating contents, permanently elevating contents on pedestals or shelves above the base flood elevation or determining that property owners can safely remove contents without risk to lives and that the contents will be located to a specified site out of the floodplain.
(Ord. --, passed 4-27-2018)
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