Ord #177 - Flood Plain Management Ordinance

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not less than one square inch for every square foot of enclosed area subject to flooding unless a registered professional engineer or architect certifies that a smaller net area would suffice. The automatic openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of flood waters without any form of human intervention; and (ii) That the enclosed area will be designed of flood resistant materials in accordance with the FP3 or FP4 classifications in the State Building Code and shall be used solely for building access, parking of vehicles or storage. DIVISION 6 GENERAL FLOODPLAIN DISTRICT (GF) 78-1128 Permitted Uses: (1) The uses listed in Section 78-1116 of this ordinance, Floodway District Permitted Uses, are permitted uses. (2) All other uses are subject to the floodway/flood fringe evaluation criteria specified in Section 78-1129 below. Division 4 applies if the proposed use is determined to be in the Floodway District. Division 5 applies if the proposed use is determined to be in the Flood Fringe District. 78-1129 Procedures for Floodway and Flood Fringe Determinations: (1) Upon receipt of an application for a permit or other approval within the General Floodplain District, the City Administrator must obtain, review and reasonably utilize any regional flood elevation and floodway data available from a federal, state, or other source. (2) If regional flood elevation and floodway data are not readily available, the applicant must furnish additional information, as needed, to determine the regulatory flood protection elevation and whether the proposed use would fall within the Floodway or Flood Fringe District. Information must be consistent with accepted hydrological and hydraulic engineering standards and the standards in Section 78-1129 (3) below. (3) The determination of floodway and flood fringe must include the following components, as applicable: (a) Estimate the peak discharge of the regional (195 chance) flood. (b) Calculate the water surface profile of the regional flood based upon a hydraulic analysis of the stream channel and overbank areas. (c) Compute the floodway necessary to conveyor store the regional flood without increasing flood stages more than one-half (0.5) foot. A lesser stage increase than 0.5 foot is required if, as a result of the stage increase, increased flood damages would result. An equal degree of encroachment on both sides of the stream within the reach must be assumed in computing floodway boundaries. (d)The applicant shall be responsible to submit one copy of the above information to a designated engineer or other expert person or agency for technical assistance in determining whether the proposed use is in the floodway or flood fringe district and to determine the regulatory flood protection elevation. Procedures consistent with 13