(A) Determining elevations. Structures must be placed in accordance with any floodplain regulations applicable to the site. Where these controls do not exist, the elevation to which the lowest floor, including basement, is placed or flood proofed must be determined as follows:
(1) For lakes, by placing the lowest floor at a level at least three feet above the highest known water level, or three feet above the ordinary high water level, whichever is higher.
(2) For rivers and streams, by placing the lowest floor at least three feet above the highest known flood elevation. If highest known flood elevation is not available, by placing the lowest floor at least three feet above the highest known flood elevation, or by conducting a technical evaluation to determine effects of proposed construction upon flood stages and flood flows and to establish a flood protection elevation. Technical evaluations must be done by a qualified engineer or hydrologist consistent with Minn. Rules Parts 6120.5000 through 6120.6200.
(B) Methods for placement.
(1) In addition to the lowest floor, all service utilities must be elevated or water-tight to the elevation determined in division (A).
(2) If elevation methods involving fill would result in filling in the SIZ, then structures must instead be elevated through floodproofing methods in accordance with § 152.121(B)(3) below.
(3) If the structure is floodproofed, then it must be built to resist hydrostatic pressure through elevation methods such as blocks, pilings, filled stem walls, elevated concrete pad, internally flooded enclosed areas, or through other accepted engineering practices consistent with FEMA technical bulletins 1, 2, and 3.
(C) Water-oriented accessory structures may have the lowest floor placed lower than the elevation determined above in divisions (A) or (B) if the structure is constructed of flood-resistant materials to the elevation, electrical and mechanical equipment is placed above the elevation and, if long duration flooding is anticipated, the structure is built to withstand ice action and wind-driven waves and debris.
(Ord. 47, passed 7-23-02; Am. Ord. 97-2021, passed 7-20-21)