Duluth UDC § 837.05

Areas of special flood hazard may include designated "AO" shallow flooding areas. These areas have base flood depths of 1 to 3 feet above ground, with no clearly defined channel. In these areas the following provisions apply: 1. New and all substantial improvements of residential and nonresidential structures shall have the lowest floor, including basement, elevated to no lower than 1 foot above the flood depth number in feet specified on the flood insurance rate map (FIRM), above the highest adjacent grade. If no flood depth number is specified, the lowest floor, including basement, shall be elevated at least 3 feet above the highest adjacent grade. Openings sufficient to facilitate the unimpeded movements of flood waters shall be provided in accordance with standards of 837.01(5). 2. New and substantial improvements of a non-residential structure may be flood-proofed in lieu of elevation. The structure, together with attendant utility and sanitary facilities, must be designed to be watertight to the specified FIRM flood level plus 1 foot above the highest adjacent grade, with walls substantially impermeable to the passage of water, and structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy. A registered professional engineer or architect shall certify that the design and methods of construction are in accordance with 240 | P a g e Article Eight. Environmental Protection accepted standards of practice and shall provide such certification to the Director of the Planning and Development Department using the FEMA Floodproofing Certificate along with the design and operation/maintenance plan; and, 3. Drainage paths shall be provided to guide floodwater around and away from any proposed structure.