Agenda - Council Work Session - 10/17/2023 - Special

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1 1. The structure must be adequately anchored to prevent flotation, collapse or 2 lateral movement and designed to equalize hydrostatic flood forces on exterior 3 walls; and 4 2. Any mechanical and utility equipment in the structure must be elevated to or 5 above the regulatory flood protection elevation or properly floodproofed. 6 d. As an alternative, an accessory structure may be internally/wet floodproofed to the FP-3 or 7 FP-4 floodproofing classifications in the Minnesota State Building Code, provided the 8 accessory structure constitutes a minimal investment and does not exceed 576 square feet in 9 size. A detached garage may only be used for parking of vehicles and limited storage. All 10 structures must meet the following standards: 11 1. To allow for the equalization of hydrostatic pressure,there must bea minimum of two 12 "automatic" openings in the outside walls of the structure, with a total net area of not 13 less than one square inch for every square foot of enclosed area subject to flooding; 14 and 15 2. There must be openings on at least two sides of the structure and the bottom of all 16 openings must be no higher than one foot above the lowest adjacent grade to the 17 structure. Using human intervention to open a garage door prior to flooding will not 18 satisfy this requirement for automatic openings. 19 (4) Structural works for flood control that will change the course, current or cross section of 20 protected wetlands or public waters are subject to the provisions of Minn. Stats. § 103G.245. 21 (5) A levee, dike or floodwall constructed in the floodway must not cause an increase to the one 22 percent chance or regional flood. The technical analysis must assume equal conveyance or 23 storage loss on both sides of a stream. 24 6) Floodway developments must not adversely affect the hydraulic capacity of the channel and 25 adjoining floodplain of any tributary watercourse or drainage system. 26 27 924 Flood Fringe District(FF) 28 (A) Permitted uses. Permitted uses are those uses of land or structures allowed in the underlying zoning 29 district(s)that comply with the standards in subsection (b) below. 30 (B) Standards for flood fringe permitted uses. 31 (1) All structures, including accessory structures, must be elevated on fill so that the lowest floor, 32 as defined, is at or above the regulatory flood protection elevation. The finished fill elevation 33 for structures must be no lower than one foot below the regulatory flood protection elevation 34 and the fill must extend at the same elevation at least 15 feet beyond the outside limits of the 35 structure. 36 a. All service utilities,including ductwork, must be elevated or water-tight to prevent infiltration 37 of floodwaters. 38 b. As an alternative to elevation on fill, an accessory structure that constitutes a minimal 39 investment and that does not exceed 576 square feet in size may be internally floodproofed 40 in accordance with section 923(D)(3). 41 (2) The cumulative placement of fill or similar material on a parcel must not exceed 1,000 cubic 42 yards,unless the fill is specifically intended to elevate a structure in accordance with subsection 43 (a) above, or if allowed as a conditional use under section 924(C)(3) below. 44 (3) The storage of any materials or equipment must be elevated on fill to the regulatory flood 45 protection elevation. 46 (4) The storage or processing of materials that are, in time of flooding, flammable, explosive, or 47 potentially injurious to human,animal, or plant life is prohibited. 48 (5) Fill must be properly compacted and the slopes must be properly protected by the use of riprap, 49 vegetative cover or other acceptable method. Page 122 of 160