§ 152.042 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 § 152.043, if otherwise allowed in the underlying zoning district.

   (A)   Structures accessory to primary uses listed in § 152.040(A) through (C) above and primary uses listed in § 152.042(B) through (C) below.

   (B)   Extraction, fill and storage of soil, sand, gravel, and other materials.

   (C)   Marinas, boat rentals, permanent docks, piers, wharves, water control structures, and navigational facilities.

   (D)   Storage yards for equipment, machinery, or materials.

   (E)   Fences that have the potential to obstruct flood flows.

   (F)   Levees or dikes intended to protect agricultural crops for a frequency flood event equal to or less than the ten (10)-year frequency flood event.

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

§ 152.043 STANDARDS FOR FLOODWAY CONDITIONAL USES.

   (A)   A conditional use must not cause any increase in flood damages, nor any increase in flood elevations in areas where a floodway has been established, as certified by a registered professional engineer.

   (B)   Fill; Storage of materials and equipment.

      (1)   Fill, dredge spoil, and other similar materials deposited or stored in the flood plain must be protected from erosion by vegetative cover, mulching, riprap or other acceptable method. Permanent sand and gravel operations and similar uses must be covered by a long-term site development plan.

      (2)   Temporary placement of fill, other materials, or equipment which would cause an increase to the stage of the one percent (1%) chance or regional flood may only be allowed if the City Council has approved a plan that assures removal of the materials from the floodway based upon the flood warning time available.

   (C)   Accessory structures. Accessory structures, as identified in § 152.042(A), may be permitted, provided that:

      (1)   Structures are not intended for human habitation;

      (2)   Structures will have a low flood damage potential;

      (3)   Structures will be constructed and placed so as to offer a minimal obstruction to the flow of flood waters;

      (4)   Structures must be elevated on fill or structurally dry flood proofed and watertight to the regulatory flood protection elevation. Certifications consistent with § 152.111(C) shall be required;

      (5)   As an alternative, an accessory structure may be flood proofed in a way to accommodate internal flooding. 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, have a 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. A floodproofing certification consistent with § 152.111(C) shall be required.

   (D)   Structural works for flood control that will change the course, current or cross section of protected wetlands or public waters are subject to the provisions of M.S. § 103G.245.

   (E)   A levee, dike or floodwall constructed in the floodway must not cause an increase to the one percent (1%) chance or regional flood. The technical analysis must assume equal conveyance or storage loss on both sides of a stream.

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

FLOOD FRINGE DISTRICT (FF)

§ 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)