Agenda - Planning Commission - 04/27/2023

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1 (i) The minimum area of openings in the walls where internal flooding is to be used as a 2 floodproofing technique. There shall be a minimum of two openings on at least two 3 sides of the structure and the bottom of all openings shall be no higher than one foot 4 above grade.The automatic openings shall have a minimum net area of not less than 5 one square inch for every square foot of enclosed area subject to flooding unless a 6 registered professional engineer or architect certifies that a smaller net area would 7 suffice. The automatic openings may be equipped with screens, louvers, valves, or 8 other coverings or devices provided that they permit the automatic entry and exit of 9 flood waters without any form of human intervention; and 10 (ii) That the enclosed area will be designed of flood resistant materials in accordance 11 with the FP-3 or FP-4 classifications in the Minnesota State Building Code and shall be 12 used solely for building access, parking of vehicles, or storage. 13 14 925 General Floodplain District (GF) 15 (A) Permitted uses. 16 (1) The uses listed in [section] 117-183(a), floodway district permitted uses, are permitted uses. 17 (2) All other uses are subject to the floodway/flood fringe evaluation criteria specified in [section] 18 117-185(b) below. Section 117-183 applies if the proposed use is determined to be in the 19 floodway district. Section 117-184 applies if the proposed use is determined to be in the flood 20 fringe district. 21 (B) Procedures for floodway and flood fringe determinations. 22 (1) Upon receipt of an application for a permit or other approval within the general floodplain 23 district,the zoning administrator must obtain, review and reasonably utilize any regional flood 24 elevation and floodway data available from a federal, state, or other source. 25 (2) If regional flood elevation and floodway data are not readily available, the applicant must 26 furnish additional information, as needed, to determine the regulatory flood protection 27 elevation and whether the proposed use would fall within the floodway or flood fringe district. 28 Information must be consistent with accepted hydrological and hydraulic engineering 29 standards and the standards in [section] 117-185(b)(3) below. 30 (3) The determination of floodway and flood fringe must include the following components, as 31 applicable: 32 a. Estimate the peak discharge of the regional (one percent chance)flood. 33 b. Calculate the water surface profile of the regional flood based upon a hydraulic analysis of 34 the stream channel and overbank areas. 35 c. Compute the floodway necessary to convey or store the regional flood without increasing 36 flood stages more than one-half foot.A lesser stage increase than one-half foot is required if, 37 as a result of the stage increase, increased flood damages would result. An equal degree of 38 encroachment on both sides of the stream within the reach must be assumed in computing 39 floodway boundaries. 40 (4) The zoning administrator will review the submitted information and assess the technical 41 evaluation and the recommended floodway and/or flood fringe district boundary. The 42 assessment must include the cumulative effects of previous floodway encroachments. The 43 zoning administrator may seek technical assistance from a designated engineer or other expert 44 person or agency, including the Minnesota Department of Natural Resources, before 45 presenting the technical evaluation and findings to the city council. The city council must 46 formally accept the technical evaluation and the recommended floodway and/or flood fringe 47 district boundary or deny the permit application. The city council, prior to official action, may 48 submit the application and all supporting data and analyses to the Federal Emergency Page 119 of 147