New construction or substantial improvements of structures including manufactured homes shall have the lowest floor including basement elevated to or above the base flood elevation as may be determined in § 153.036 or two feet above the highest adjacent grade where no elevation data is available.
(A) New construction or substantial improvements of structures, including manufactured homes, shall have the lowest floor (including basement) elevated at least two feet above the highest adjacent grade next to the proposed foundation of the structure.
(B) Fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically (without human intervention) allow for the entry and exit of flood waters for the purpose of equalizing hydrostatic flood forces on exterior walls. Designs for meeting this requirement must either be certified by a licensed professional engineer or a licensed architect or meet the following criteria:
(1) A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;
(2) The bottom of all the openings shall be no higher than one foot above the lowest adjacent finished grade; and
(3) Openings may be equipped with louvers, valves, screens or other coverings or openings provided they permit the automatic entry and exit of flood waters.
(Ord. 1-1987, passed 4-13-1987)