Ordinance - #23-14 - 11/14/2023 - Laserfiche WebLink

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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 foini of human intervention; and 10 (ii) That the enclosed area will be designed of flood resistant materials in accordance with 11 the FP-3 or FP-4 classifications in the Minnesota State Building Code and shall be used 12 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 923(A), floodway district peiniitted uses, are permitted uses. 17 (2) All other uses are subject to the floodway/flood fringe evaluation criteria specified in [section] 18 925(b) below. Section 923 applies if the proposed use is determined to be in the floodway district. 19 Section 924 applies if the proposed use is determined to be in the flood fringe district. 20 (B) Procedures_ for floodway and flood fringe determinations. 21 (1) Upon receipt of an application for a peiniit or other approval within the general floodplain 22 district, the zoning administrator must obtain, review and reasonably utilize any regional flood 23 elevation and floodway data available from a federal, state, or other source. 24 (2) If regional flood elevation and floodway data are not readily available, the applicant must furnish 25 additional infoiniation, as needed, to determine the regulatory flood protection elevation and 26 whether the proposed use would fall within the floodway or flood fringe district. Information 27 must be consistent with accepted hydrological and hydraulic engineering standards and the 28 standards in section 925(B)(3) below. 29 (3) The determination of floodway and flood fringe must include the following components, as 30 applicable: 31 a. Estimate the peak discharge of the regional (one percent chance) flood. 32 b. Calculate the water surface profile of the regional flood based upon a hydraulic analysis of the 33 stream channel and overbank areas. 34 c. Compute the floodway necessary to convey or store the regional flood without increasing flood 35 stages more than one-half foot. A lesser stage increase than one-half foot is required if, as a 36 result of the stage increase, increased flood damages would result. An equal degree of 37 encroachment on both sides of the stream within the reach must be assumed in computing 38 floodway boundaries. 39 (4) The zoning administrator will review the submitted information and assess the technical 40 evaluation and the recommended floodway and/or flood fringe district boundary. The assessment 41 must include the cumulative effects of previous floodway encroachments. The zoning 42 administrator may seek technical assistance from a designated engineer or other expert person 43 or agency, including the Minnesota Department of Natural Resources, before presenting the 44 technical evaluation and findings to the city council. The city council must formally accept the 45 technical evaluation and the recommended floodway and/or flood fringe district boundary or 46 deny the permit application. The city council, prior to official action, may submit the application 47 and all supporting data and analyses to the Federal Emergency Management Agency (FEMA), 48 the Minnesota Department of Natural Resources, or the planning commission for review and 49 comment. 50 (5) Once the floodway and flood fringe district boundaries have been determined, the city council 51 shall refer the matter back to the zoning administrator to process the permit application consistent 52 with the applicable provisions of sections 923 and 924. Attachment A — Ordinance #23-14 Page 110 of 141