§ 152.050 PERMITTED USES.

   Permitted uses are those uses of land or structures allowed in the underlying zoning district(s) that comply with the standards in § 152.051. If no pre-existing, underlying zoning districts exist, then any residential or nonresidential structure or use of a structure or land is a permitted use provided it does not constitute a public nuisance.

(Ord. 481, passed 2-16-2021)

§ 152.051 STANDARDS FOR FLOOD FRINGE PERMITTED USES.

   (A)   All structures, including accessory structures, must be elevated on fill so that the lowest floor, as defined, is at or above the regulatory flood protection elevation. The finished fill elevation for structures must be no lower than one (1) foot below the regulatory flood protection elevation and the fill must extend at the same elevation at least fifteen (15) feet beyond the outside limits of the structure. Elevations must be certified by a registered professional engineer, land surveyor or other qualified person designated by the community.

   (B)   Accessory structures. As an alternative to the fill requirements of division (A) above, structures accessory to the uses identified in § 152.050 may be designed to accommodate the inundation of floodwaters, meeting the following provisions:

      (1)   The accessory structure constitutes a minimal investment and satisfy the development requirements in § 152.031.

      (2)   Any enclosed accessory structure shall not exceed five hundred and seventy-six (576) square feet in size, and only be used for parking and storage. Any such structure shall be designed and certified by a registered professional engineer, or be designed in accordance with the following floodproofing standards:

         (a)   To allow for the equalization of hydrostatic pressure, there shall be a minimum of two (2) openings on at least two (2) sides of the structure and the bottom of all openings shall be no higher than one (1) foot above grade. The openings shall have a minimum net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding, and shall allow automatic entry and exit of floodwaters without human intervention.

   (C)   The cumulative placement of fill or similar material on a parcel must not exceed one thousand (1,000) cubic yards, unless the fill is specifically intended to elevate a structure in accordance with (A) above, or if allowed as a conditional use under § 152.052(C) below.

   (D)   All service utilities, including ductwork, must be elevated or water-tight to prevent infiltration of floodwaters.

   (E)   All fill must be properly compacted and the slopes must be properly protected by the use of riprap, vegetative cover or other acceptable method.

   (F)   All new principal structures must have vehicular access at or above an elevation not more than two (2) feet below the regulatory flood protection elevation, or must have a flood warning/emergency evacuation plan acceptable to the City Council.

   (G)   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 (in feet) multiplied by the velocity (in feet per second) would exceed a product of four (4) upon occurrence of the regional one percent (1%) chance flood.

   (H)   Manufactured homes and recreational vehicles must meet the standards of §§ 152.100 and 152.101 of this chapter.

(Ord. 481, passed 2-16-2021)

§ 152.052 CONDITIONAL USES.

   The following uses may be allowed as conditional uses following the standards and procedures set forth in § 152.113 of this chapter and further subject to the standards set forth in § 152.053, if otherwise allowed in the underlying zoning district(s).

   (A)   The placement of flood proofed nonresidential basements below the regulatory flood protection elevation. Residential basements, are not allowed below the regulatory flood protection elevation.

   (B)   The cumulative placement of more than one thousand (1,000) cubic yards of fill when the fill is not being used to elevate a structure in accordance with § 152.051(A) of this chapter.

   (C)   The use of methods other than fill to elevate structures above the regulatory flood protection elevation. This includes the use of: stilts, pilings, filled stem walls, or above-grade, internally flooded enclosed areas such as crawl spaces or tuck under garages, meeting the standards in § 152.053(E).

(Ord. 481, passed 2-16-2021)

§ 152.053 STANDARDS FOR FLOOD FRINGE CONDITIONAL USES.

   (A)   The standards for permitted uses in the flood fringe, listed in § 152.051(C) through (H), apply to all conditional uses.

   (B)   All areas of non-residential structures, including basements, to be placed below the regulatory flood protection elevation must be flood proofed in accordance with classifications in the State Building Code. Structurally dry flood proofing must meet the FP1 or FP2 flood proofing classification in the State Building Code, which requires making the structure watertight with the walls substantially impermeable to the passage of water and with structural components capable of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. A floodproofing certification consistent with § 152.111(C) shall be required.

   (C)   The placement of more than one thousand (1,000) cubic yards of fill or other similar material on a parcel (other than for the purpose of elevating a structure to the regulatory flood protection elevation) must comply with an approved erosion/sedimentation control plan.

      (1)   The plan must clearly specify methods to be used to stabilize the fill on site for a flood event at a minimum of the regional one percent (1%) chance flood event.

      (2)   The plan must be prepared and certified by a registered professional engineer or other qualified individual acceptable to the City Council.

      (3)   The plan may incorporate alternative procedures for removal of the material from the flood plain if adequate flood warning time exists.

   (D)   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. The base or floor of an enclosed area shall be considered above-grade and not a structure's basement or lowest floor if:

      (1)   The enclosed area is above-grade on at least one (1) side of the structure;

      (2)   It is designed to internally flood; and

      (3)   It is used solely for parking of vehicles, building access or storage.

   (E)   These alternative elevation methods are subject to the following additional standards:

      (1)   Above-grade, fully enclosed areas such as crawl spaces or tuck under garages must be designed to internally flood and include a minimum of two (2) openings on at least two (2) sides of the structure. The bottom of all openings shall be no higher than one (1) foot above grade, and have a minimum net area of not less than one (1) 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 § 152.111(C) shall be required. The structure shall be subject to a deed-restricted non-conversion agreement with the issuance of any permit.

(Ord. 481, passed 2-16-2021)

GENERAL FLOOD PLAIN DISTRICT (GF)

§ 152.060 PERMITTED USES.

   (A)   The uses listed in § 152.040 of this chapter, Floodway District Permitted Uses, are permitted uses.

   (B)   All other uses are subject to the floodway/flood fringe evaluation criteria specified in § 152.061 below. Sections 152.040 et seq. apply if the proposed use is determined to be in the Floodway District. Sections 152.050 et seq. apply if the proposed use is determined to be in the Flood Fringe District.

(Ord. 481, passed 2-16-2021)

§ 152.061 PROCEDURES FOR DETERMINING FLOODWAY BOUNDARIES AND REGIONAL FLOOD ELEVATIONS.

   (A)   Requirements for detailed studies. Developments greater than fifty (50) lots or five (5) acres, or as requested by the Community Development Director, shall be subject to a detailed study to determine the regulatory flood protection elevation and the limits of the Floodway District. The determination of the floodway and flood fringe must be consistent with accepted hydrological and hydraulic engineering standards, and must include the following components, as applicable:

      (1)   Estimate the peak discharge of the regional one percent chance (1%) flood.

      (2)   Calculate the water surface profile of the regional flood based upon a hydraulic analysis of the stream channel and overbank areas.

      (3)   Compute the floodway necessary to convey or store the regional flood without increasing flood stages more than one-half (0.5) foot. A lesser stage increase than one-half (0.5) foot is required if, as a result of the stage increase, increased flood damages would result. An equal degree of encroachment on both sides of the stream within the reach must be assumed in computing floodway boundaries, unless development or geographic features warrant other analysis, as approved by the Department of Natural Resources.

   (B)   Alternative methods. For areas where a detailed study is not available or required, the regional flood elevation must be identified to determine the boundaries of the special flood hazard area. The Community Development Director must use the best available data to determine the regional flood elevation. The entire flood plain must be treated as floodway until there is a floodway determination.

      (1)   In those areas of the Special Flood Hazard Area where the floodway has not been determined, allowable uses are restricted to those identified in §§ 152.040 and 152.042. The proposed development must not increase flood stages more than one-half (0.5) foot, as determined by a professional engineer or by using accepted engineering practices approved by the Community Development Director. A stage increase less than one-half (0.5) foot must be used if increased flood damages would result.

      (2)   If buildings or other development prohibited in floodways are proposed, a floodway/flood fringe determination is required to verify the development is within the flood fringe. The floodway/flood fringe determination must be done by a professional engineer or by using other accepted engineering practices approved by the Community Development Director. Any such proposal must assume a one-half (0.5) foot stage increase for the purposes of determining the regulatory flood protection elevation to accommodate for future cumulative impacts.

   (C)   The Community Development Director will review the submitted information and assess the technical evaluation and the recommended Floodway and/or Flood Fringe District boundary. The assessment must include the cumulative effects of previous floodway encroachments. The Community Development Director may seek technical assistance from an engineer or other expert person or agency, including the Department of Natural Resources. Based on this assessment, the Community Development Director may approve or deny the application.

   (D)   Once the Floodway and Flood Fringe District boundaries have been determined, the Community Development Director must process the permit application consistent with the applicable provisions of §§ 152.040 through 152.053 of this chapter.

(Ord. 481, passed 2-16-2021)