Agenda - Planning Commission - 04/27/2023

Home

1 (1) All uses. A conditional use must not cause any increase in the stage of the one percent chance 2 or regional flood or cause an increase in flood damages in the reach or reaches affected. 3 (2) Fill;storage of materials and equipment: 4 a. The storage or processing of materials that are, in time of flooding, flammable, 5 explosive, or potentially injurious to human, animal, or plant life is prohibited. 6 b. Fill, dredge spoil, and other similar materials deposited or stored in the floodplain must 7 be protected from erosion by vegetative cover, mulching, riprap or other acceptable 8 method. Permanent sand and gravel operations and similar uses must be covered by a 9 long-term site development plan. 10 C. Temporary placement of fill, other materials, or equipment which would cause an 11 increase to the stage of the one percent chance or regional flood may only be allowed 12 if the city has approved a plan that assures removal of the materials from the floodway 13 based upon the flood warning time available. 14 (3) Accessory structures: 15 a. Accessory structures must not be designed for human habitation. 16 b. Accessory structures, if permitted, must be constructed and placed on the building site 17 so as to offer the minimum obstruction to the flow of flood waters: 18 1. Whenever possible, structures must be constructed with the longitudinal axis 19 parallel to the direction of flood flow; and 20 2. So far as practicable, structures must be placed approximately on the same flood 21 flow lines as those of adjoining structures. 22 C. Accessory structures must be elevated on fill or structurally dry floodproofed in 23 accordance with the FP-1 or FP-2 floodproofing classifications in the Minnesota State 24 Building Code.All floodproofed accessory structures must meet the following additional 25 standards: 26 1. The structure must be adequately anchored to prevent flotation, collapse or 27 lateral movement and designed to equalize hydrostatic flood forces on exterior 28 walls; and 29 2. Any mechanical and utility equipment in the structure must be elevated to or 30 above the regulatory flood protection elevation or properly floodproofed. 31 d. As an alternative, an accessory structure may be internally/wet floodproofed to the FP-3 or 32 FP-4 floodproofing classifications in the Minnesota State Building Code, provided the 33 accessory structure constitutes a minimal investment and does not exceed 576 square feet in 34 size. A detached garage may only be used for parking of vehicles and limited storage. All 35 structures must meet the following standards: 36 1. To allow for the equalization of hydrostatic pressure,there must be a minimum of two 37 "automatic" openings in the outside walls of the structure, with a total net area of not 38 less than one square inch for every square foot of enclosed area subject to flooding; 39 and 40 2. There must be openings on at least two sides of the structure and the bottom of all 41 openings must be no higher than one foot above the lowest adjacent grade to the 42 structure. Using human intervention to open a garage door prior to flooding will not 43 satisfy this requirement for automatic openings. 44 (4) Structural works for flood control that will change the course, current or cross section of 45 protected wetlands or public waters are subject to the provisions of Minn. Stats. § 103G.245. 46 (5) A levee, dike or floodwall constructed in the floodway must not cause an increase to the one 47 percent chance or regional flood. The technical analysis must assume equal conveyance or 48 storage loss on both sides of a stream. Page 116 of 147