In all areas of special flood hazard, the following standards are required:
A. Anchoring:
1. All new construction and substantial improvements shall be adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.
2. All manufactured homes shall meet the anchoring standards of section 12-4-5 of this chapter.
B. Construction Materials And Methods: All new construction and substantial improvements shall be constructed:
1. With materials and utility equipment resistant to flood damage;
2. Using methods and practices that minimize flood damage;
3. Ensuring electrical, heating, ventilation, plumbing, air conditioning equipment and other service facilities are designed or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
4. Within zones AH or AO, so that there are adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures.
C. Elevation Requirements For Lowest Floor: Residential construction, new or substantial improvements, shall have the lowest floor, including basement:
1. In Zone AO, elevated above the highest adjacent grade to a height equal to or exceeding the depth number specified in feet on the FIRM, or elevated at least two feet (2') above the highest adjacent grade if no depth number is specified. The city recommends that the lowest floor be elevated above the highest adjacent grade to a height exceeding the depth number specified in feet on the FIRM by at least one foot (1'), or elevated at least three feet (3') above the highest adjacent grade if no depth number is specified. (1973 Code § 18.05.010)
2. In zone A, elevated to or above the base flood elevation, as determined by this city. The city recommends the lowest floor be elevated at least one foot (1') above the base flood elevation, as determined by the city.
3. In all other zones, elevated to or above the base flood elevation. The city recommends the lowest floor be elevated at least one foot (1') above the base flood elevation.
D. Lowest Floor Certification Requirements: Upon completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor and verified by the city building inspector to be properly elevated. The certification shall be provided to the flood plain administrator using the current FEMA elevation certificate. The city recommends the certification of the lowest floor, including basement, be performed after the slab has been poured for slab on grade or when the lowest floor is complete and prior to the start of framing. (1973 Code § 18.05.010; amd. 2001 Code)
E. Nonresidential Floodproofing Requirements: Nonresidential construction shall either be elevated to conform with subsection C of this section or together with attendant utility and sanitary facilities:
1. Will be floodproofed below the elevation recommended under subsection C of this section so that the structure is watertight with walls substantially impermeable to the passage of water;
2. Will have the structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;
3. Will be certified by a registered professional engineer or architect that the standards of subsection C of this section are satisfied. The certification shall be provided to the flood plain administrator.
F. Requirements For Areas Below The Lowest Floor: All new construction and substantial improvements with fully enclosed areas below the lowest floor (excluding basements) that are usable solely for parking of vehicles, building access or storage, and which are subject to flooding, 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 licensed professional engineer or architect or meet or exceed the following minimum criteria:
1. Must have 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;
2. The bottom of all such openings will be no higher than one foot (1') above the lowest adjacent finished grade. Openings may be equipped with louvers, valves, screens or other coverings or devices provided they permit the automatic entry and exit of flood waters. (1973 Code § 18.05.010)