(1) Permitted uses. The following uses, subject to the standards set forth in § 1103.05(2), are permitted uses if otherwise allowed in the underlying base zoning district or any applicable overlay district:
(a) General farming, pasture, grazing, outdoor plant nurseries, horticulture, truck farming, forestry, sod farming and wild crop harvesting.
(b) Industrial-commercial loading areas, parking areas and airport landing strips.
(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, seasonal docks, 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 lawns, gardens, parking areas and play areas as long as no permanent structures are constructed.
(e) Railroads, streets, bridges, utility transmission lines and pipelines, provided that the Department of Natural Resources' Area Hydrologist is notified at least ten days prior to issuance of any permit, and that the standards in divisions (4)(a), (4)(c)1., and (4)(f) of this section are met.
(2) Standards for floodway permitted uses.
(a) The use must have a low flood damage potential.
(b) With the exception of the uses listed in division (1)(e), the use must not obstruct flood flows or increase flood elevations and must not involve structures, fill, obstructions, excavations or storage of materials or equipment.
(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 upon occurrence of the regional (1% chance) flood.
(3) Conditional uses. The following uses may be allowed as conditional uses following the standards and procedures set forth in § 1103.11(4) of this chapter and further subject to the standards set forth in division (4), if otherwise allowed in the underlying zoning district or any applicable overlay district.
(a) Structures accessory to the uses listed in division (1) and the uses listed below.
(b) Extraction and storage of sand, gravel and other materials.
(c) Marinas, boat rentals, permaent docks, piers, wharves and water control structures,
(d) Storage yards for equipment, machinery or materials.
(e) Placement of fill or construction of fences that obstruct flood flows. Farm fences, as defined in § 1103.03, are permitted uses.
(f) Travel-ready recreational vehicles meeting the exemption standards in § 1103.10(3).
(g) Levees or dikes intended to protect agricultural crops for a frequency flood event equal to or less than the 10-year frequency flood event.
(4) Standards for floodway conditional uses.
(a) All uses. A conditional use must not cause any increase in the stage of the 1% chance or regional flood or cause an increase in flood damages in the reach or reaches affected.
(b) Fill; storage of materials and equipment.
1. 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.
2. Fill, dredge spoil, and other similar materials deposited or stored in the floodplain 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.
3. Temporary placement of fill, other materials, or equipment which would cause an increase to the stage of the 1% percent 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.
1. Accessory structures must not be designed for human habitation.
2. Accessory structures, if permitted, must be constructed and placed on the building site so as to offer the minimum obstruction to the flow of flood waters:
a. Whenever possible, structures must be constructed with the longitudinal axis parallel to the direction of flood flow; and
b. So far as practicable, structures must be placed approximately on the same flood flow lines as those of adjoining structures.
3. Accessory structures shall be elevated on fill or structurally dry floodproofed in accordance with the FP-1 or FP-2 flood-proofing classifications in the State Building Code. All floodproofed accessory structures must meet the following additional standards:
a. The structure must be adequately anchored to prevent flotation, collapse or lateral movement and designed to equalize hydrostatic flood forces on exterior walls; and
b. Any mechanical and utility equipment in the structure must be elevated to or above the regulatory flood protection elevation or properly floodproofed.
4. As an alternative, an accessory structure may be internally/wet floodproofed to the FP-3 or FP-4 flood-proofing classification in the State Building Code, provided the accessory structure constitutes a minimal investment, does not exceed 576 square feet in the size. A detached garage may only be used for parking of vehicles and limited storage. All flood-proofed accessory structures must meet the following standards:
a. To allow for the equalization of hydrostatic pressure, there must be a minimum of two automatic openings in the outside walls of the structure, with a total net area of not less than one square inch for every square foot of enclosed area subject to flooding; and
b. 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. Using human intervention to open a garage door prior to flooding will not satisfy this requirement for automatic openings.
(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 1% chance or regional flood. The technical analysis must assume equal conveyance or storage loss on both sides of a stream.
(f) Floodway developments must not adversely affect the hydraulic capacity of the channel and adjoining floodplain of any tributary watercourse or drainage system.
(Ord. 10-15, passed 11-23-2015)