§ 152.031 FLOOD CAPACITY.

   Flood plain developments must not adversely affect the hydraulic capacity of the channel and adjoining flood plain of any tributary watercourse or drainage system.

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

§ 152.032 STORAGE AND PROCESSING OF MATERIALS.

   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.

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

§ 152.033 CRITICAL FACILITIES.

   Critical facilities, as defined in § 152.015, are to be located, so that the lowest floor is not less than two (2) feet above the regional flood elevation, or the five hundred (500)-year flood elevation, whichever is higher.

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

FLOODWAY DISTRICT (FW)

§ 152.040 PERMITTED USES.

   The following uses, subject to the standards set forth in § 152.041, are permitted uses if otherwise allowed in the underlying zoning district or any applicable overlay district:

   (A)   General farming, pasture, grazing, farm fences, outdoor plant nurseries, horticulture, forestry, sod farming, and wild crop harvesting.

   (B)   Industrial and commercial loading areas, parking areas, streets, trails, airport landing strips, railroads, bridges, culverts, utility transmission lines and pipelines.

   (C)   Open space uses, including but not limited to private and public golf courses, tennis courts, driving ranges, archery ranges, picnic grounds, boat launching ramps, swimming areas, parks, wildlife and nature preserves, game farms, fish hatcheries, shooting preserves, hunting and fishing areas, and single or multiple purpose recreational trails.

   (D)   Residential yards, lawns, gardens, parking areas, and play areas, provided these uses do not include associated accessory structures.

   (E)   Grading or land alterations associated with stabilization projects.

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

§ 152.041 STANDARDS FOR FLOODWAY PERMITTED USES.

   (A)   The use must have a low flood damage potential.

   (B)   The use must not involve structures or obstruct flood flows. The 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.

   (C)   Any facility that will be 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.

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

§ 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)