Agenda - Planning Commission - 04/27/2023

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1 (6) Floodway developments must not adversely affect the hydraulic capacity of the channel and 2 adjoining floodplain of any tributary watercourse or drainage system. 3 4 924 Flood Fringe District (FF) 5 (A) Permitted uses. Permitted uses are those uses of land or structures allowed in the underlying zoning 6 district(s)that comply with the standards in subsection (b) below. 7 (B) Standards for flood fringe permitted uses. 8 (1) All structures, including accessory structures, must be elevated on fill so that the lowest floor, 9 as defined, is at or above the regulatory flood protection elevation. The finished fill elevation 10 for structures must be no lower than one foot below the regulatory flood protection elevation 11 and the fill must extend at the same elevation at least 15 feet beyond the outside limits of the 12 structure. 13 a. All service utilities, including ductwork, must be elevated or water-tight to prevent infiltration 14 of floodwaters. 15 b. As an alternative to elevation on fill, an accessory structure that constitutes a minimal 16 investment and that does not exceed 576 square feet in size may be internally floodproofed 17 in accordance with [section] 117-183(d)(3). 18 (2) The cumulative placement of fill or similar material on a parcel must not exceed 1,000 cubic 19 yards, unless the fill is specifically intended to elevate a structure in accordance with subsection 20 (a) above, or if allowed as a conditional use under section 117-184(c)(3) below. 21 (3) The storage of any materials or equipment must be elevated on fill to the regulatory flood 22 protection elevation. 23 (4) The storage or processing of materials that are, in time of flooding, flammable, explosive, or 24 potentially injurious to human, animal, or plant life is prohibited. 25 (5) Fill must be properly compacted and the slopes must be properly protected by the use of riprap, 26 vegetative cover or other acceptable method. 27 (6) All new principal structures must have vehicular access at or above an elevation not more than 28 two feet below the regulatory flood protection elevation, or must have a flood 29 warning/emergency evacuation plan acceptable to the city. 30 (7) Accessory uses such as yards, railroad tracks, and parking lots may be at an elevation lower 31 than the regulatory flood protection elevation. However, any facilities used by employees or 32 the general public must be designed with a flood warning system that provides adequate time 33 for evacuation if the area is inundated to a depth and velocity such that the depth (in feet) 34 multiplied by the velocity(in feet per second)would exceed a product of four upon occurrence 35 of the regional (one percent chance)flood. 36 (8) Interference with normal manufacturing/industrial plant operations must be minimized, 37 especially along streams having protracted flood durations. In considering permit applications, 38 due consideration must be given to the needs of industries with operations that require a 39 floodplain location. 40 (9) Flood fringe developments must not adversely affect the hydraulic capacity of the channel and 41 adjoining floodplain of any tributary watercourse or drainage system. 42 (10) Manufactured homes and recreational vehicles must meet the standards of section 117-188. 43 (C) Conditional uses. The following uses and activities may be allowed as conditional uses, if allowed in 44 the underlying zoning district(s)or any applicable overlay district,following the procedures in section 45 117-189(d). conditional uses must meet the standards in [subsections] (b)(4)through (10)above and 46 section 117-184(d). 47 (1) Any structure that is not elevated on fill or floodproofed in accordance with section 117- 48 184(b)(1)a. and b. 49 (2) Storage of any material or equipment below the regulatory flood protection elevation. Page 117 of 147