Agenda - Council Work Session - 10/17/2023 - Special

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1 Information must be consistent with accepted hydrological and hydraulic engineering 2 standards and the standards in section 925(B)(3) below. 3 (3) The determination of floodway and flood fringe must include the following components, as 4 applicable: 5 a. Estimate the peak discharge of the regional (one percent chance)flood. 6 b. Calculate the water surface profile of the regional flood based upon a hydraulic analysis of 7 the stream channel and overbank areas. 8 c. Compute the floodway necessary to convey or store the regional flood without increasing 9 flood stages more than one-half foot.A lesser stage increase than one-half foot is required if, 10 as a result of the stage increase, increased flood damages would result. An equal degree of 11 encroachment on both sides of the stream within the reach must be assumed in computing 12 floodway boundaries. 13 (4) The zoning administrator will review the submitted information and assess the technical 14 evaluation and the recommended floodway and/or flood fringe district boundary. The 15 assessment must include the cumulative effects of previous floodway encroachments. The 16 zoning administrator may seek technical assistance from a designated engineer or other expert 17 person or agency, including the Minnesota Department of Natural Resources, before 18 presenting the technical evaluation and findings to the city council. The city council must 19 formally accept the technical evaluation and the recommended floodway and/or flood fringe 20 district boundary or deny the permit application. The city council, prior to official action, may 21 submit the application and all supporting data and analyses to the Federal Emergency 22 Management Agency(FEMA),the Minnesota Department of Natural Resources,or the planning 23 commission for review and comment. 24 (5) Once the floodway and flood fringe district boundaries have been determined,the city council 25 shall refer the matter back to the zoning administrator to process the permit application 26 consistent with the applicable provisions of sections 923 and 924. 27 28 926 Public Utilities, Railroads, Roads, and Bridges in Floodplains. 29 (A) Public utilities. All public: utilities arid facilities such as gas, electrical, sewer, and water supply 30 systems to be located in the floodplain must be floodproofed in accordance with the Minnesota 31 State Building Code or elevated to the regulatory flood protection elevation. 32 (B) Public transportation facilities. Railroad tracks, roads, and bridges to be located within the 33 floodplain must comply with sections 923 and 924.These transportation facilities must be elevated 34 to the regulatory flood protection elevation where failure or interruption of these facilities would 35 result in danger to the public health or safety or where such facilities are essential to the orderly 36 functioning of the area. Minor or auxiliary roads or railroads may be constructed at a lower elevation 37 where failure or interruption of transportation services would not endanger the public health or 38 safety. 39 (C) On-site watersupply and sewage treatment systems. Where public utilities are not provided: 40 (1) On-site water supply systems must be designed to minimize or eliminate infiltration of flood 41 waters into the systems; and 42 (2) New or replacement on-site sewage treatment systems must be designed to minimize or 43 eliminate infiltration of flood waters into the systems and discharges from the systems into 44 flood waters and they must not be subject to impairment or contamination during times of 45 flooding. Any sewage treatment system designed in accordance with the state's current 46 statewide standards for on-site sewage treatment systems is considered to be in compliance 47 with this section. 48 49 927 Manufactured homes, Manufactured home parks, and Recreational Vehicles in Floodplains. Page 125 of 160