Packet: Regular City Council Meeting (11/04/2025)

chapter. The applicant shall be required to submit certification by a professional engineer or land surveyor, as appropriate, registered in the State of Iowa, that the finished fill, structure floor elevations, floodproofing, or other flood protection measures were accomplished in compliance with the provisions of this chapter, prior to the use or occupancy of any structure. 160.05 FLOOD PLAIN MANAGEMENT STANDARDS. 1. General Floodplain Standards. All development must be consistent with the need to minimize flood damage and meet the following applicable performance standards. Where base flood elevations have not been provided in the Flood Insurance Study, the Iowa Department of Natural Resources shall be contacted to determine (i) whether the land involved is either wholly or partly within the floodway or floodway fringe and (ii) the base flood elevation. Until a regulatory floodway is designated, no development may increase the Base Flood Elevation more than one (1) foot. The applicant will be responsible for providing the Department of Natural Resources with sufficient technical information to make such determination. Review by the Iowa Department of Natural Resources is not required for the proposed construction of new or replacement bridges or culverts where (i) the bridge or culvert is located on a stream that drains less than two square miles, and (ii) the bridge or culvert is not associated with a channel modification that constitutes a channel change as specified in 567-71.2(2), Iowa Administrative Code. A. All development shall: (1) Be designed and adequately anchored to prevent flotation, collapse, or lateral movement. (2) Use construction methods and practices that will minimize flood damage. (3) Use construction materials and utility equipment that are resistant to flood damage. B. Residential Structures. All new or substantially improved residential structures shall have the lowest floor, including basement, elevated a minimum of one foot above the base flood elevation. Construction shall be upon compacted fill which shall, at all points, be no lower than one foot above the base flood elevation and extend at such elevation at least 18 feet beyond the limits of any structure erected thereon. Alternate methods of elevating (such as piers or extended foundations) may be allowed where existing topography, street grades, or other factors preclude elevating by fill. In such cases, the methods used must be adequate to support the structure as well as withstand the various forces and hazards associated with flooding. All new residential structures located in areas that would become isolated due to flooding of surrounding ground shall be provided with a means of access that will be passable by wheeled vehicles during the base flood. However, this criterion shall not apply where the Floodplain Administrator determines there is sufficient flood warning time for the protection of life and property. When estimating flood warning time, consideration shall be given to the criteria listed in 567- 75.2(3), Iowa Administrative Code. C. Nonresidential Structures. All new or substantially improved nonresidential structures shall have the lowest floor (including basement) elevated a minimum of one foot above the base flood elevation, or together with attendant utility and sanitary systems, be floodproofed to such a level. When floodproofing is utilized, a professional engineer registered in the State of Iowa shall certify that the floodproofing methods used are adequate to withstand the flood depths, pressures, velocities, impact and uplift forces and other factors associated with the base flood; and that the structure, below the base flood elevation is watertight with walls substantially impermeable to the passage of water. A record of the certification indicating the specific elevation (in relation to North American Vertical Datum 1988) to which any structures are floodproofed shall be maintained by the Floodplain Administrator. D. All New and Substantially Improved Structures: