In all areas of special flood hazard where base flood elevation data has been provided as set forth in subsections 11-1-4B and 11-1-5B2 of this chapter, the following provisions are required:
   A.   Residential Construction:
      1.   New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above base flood elevation.
      2.   Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following minimum criteria:
         a.   A minimum of two (2) openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided.
         b.   The bottom of all openings shall be no higher than one foot (1') above grade.
         c.   Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
   B.   Nonresidential Construction: New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the base flood elevation; or, together with attendant utility and sanitary facilities, shall:
      1.   Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;
      2.   Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;
      3.   Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the CMCDP as set forth in subsection 11-1-5B3b of this chapter.
      4.   Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection A2 of this section.
      5.   Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot (1') below the floodproofed level (e.g., a building constructed to the base flood level will be rated as one foot below that level).
   C.   Manufactured Homes: All manufactured homes to be placed or substantially improved within zones A1-30, AH, and AE shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the base flood elevation and be securely anchored to an adequately anchored foundation system in accordance with the provisions of subsection 11-1-7A2 of this chapter. (Ord. 126, 5-13-1987)