Agenda - Planning Commission - 07/27/2023

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1 floodproofing must meet the FP-1 or FP-2 floodproofing classification in the Minnesota State 2 Building Code, which requires making the structure watertight with the walls substantially 3 impermeable to the passage of water and with structural components capable of resisting 4 hydrostatic and hydrodynamic loads and the effects of buoyancy. Structures wet floodproofed 5 to the FP-3 or FP-4 classification are not permitted. 6 (4) The placement of more than 1,000 cubic yards of fill or other similar material on a parcel (other 7 than for the purpose of elevating a structure to the regulatory flood protection elevation) must 8 comply with an approved erosion/sedimentation control plan. 9 a. The plan must clearly specify methods to be used to stabilize the fill on site for a flood event 10 at a minimum of the regional (one percent chance) flood event. 11 b. The plan must be prepared and certified by a registered professional engineer or other 12 qualified individual acceptable to the city. 13 c. The plan may incorporate alternative procedures for removal of the material from the 14 floodplain if adequate flood warning time exists. 15 (5) Storage of materials and equipment below the regulatory flood protection elevation must 16 comply with an approved emergency plan providing for removal of such materials within the 17 time available after a flood warning. 18 (6) Alternative elevation methods other than the use of fill may be utilized to elevate a structure's 19 lowest floor above the regulatory flood protection elevation. These alternative methods may 20 include the use of stilts, pilings, parallel walls, etc., or above -grade, enclosed areas such as crawl 21 spaces or tuck under garages. The base or floor of an enclosed area shall be considered above- 22 grade and not a structure's basement or lowest floor if: 23 a. The enclosed area is above -grade on at least one side of the structure. 24 b. It is designed to internally flood and is constructed with flood resistant materials. 25 c. It is used solely for parking of vehicles, building access or storage. The above -noted alternative 26 elevation methods are subject to the following additional standards: 27 1. Design and certification. The structure's design and as -built condition must be certified 28 by a registered professional engineer or architect as being in compliance with the general 29 design standards of the Minnesota State Building Code and, specifically, that all electrical, 30 heating, ventilation, plumbing and air conditioning equipment and other service facilities 31 must be at or above the regulatory flood protection elevation or be designed to prevent 32 flood water from entering or accumulating within these components during times of 33 flooding. 34 2. Specific standards for above -grade, enclosed areas. Above -grade, fully enclosed areas 35 such as crawl spaces or tuck under garages must be designed to internally flood and the 36 design plans must stipulate: 37 (i) The minimum area of openings in the walls where internal flooding is to be used as a 38 floodproofing technique. There shall be a minimum of two openings on at least two 39 sides of the structure and the bottom of all openings shall be no higher than one foot 40 above grade. The automatic openings shall have a minimum net area of not less than 41 one square inch for every square foot of enclosed area subject to flooding unless a 42 registered professional engineer or architect certifies that a smaller net area would 43 suffice. The automatic openings may be equipped with screens, louvers, valves, or 44 other coverings or devices provided that they permit the automatic entry and exit of 45 flood waters without any form of human intervention; and 46 (ii) That the enclosed area will be designed of flood resistant materials in accordance 47 with the FP-3 or FP-4 classifications in the Minnesota State Building Code and shall be 48 used solely for building access, parking of vehicles, or storage. 49 Page 124 of 160