15.04.160 Standards for shallow flooding areas (AO and AH zones).
A. No person shall obstruct the natural overflow areas designated as AO zones on the FIRM in order to maintain downstream base flood elevations.
B. New construction or substantial improvement to residential structures within the AO zone shall have the lowest floor (including basement) elevated above the highest adjacent grade at the building site, to or above the depth number specified on the flood hazard map (at least two feet if no depth number is specified).
C. New construction or substantial improvements to nonresidential structures within the AO zone shall either:
1. Comply with subsection (B) of this section; or
2. Together with attendant utility and sanitary facilities, be completely floodproofed to or above the depth number specified on the FIRM (at least two feet if no depth number is specified) so that any space below is watertight with walls impermeable to the passage of water and with structural components able to resist the hydrostatic and hydrodynamic loads and effects of buoyancy. Compliance with this section shall be certified by a registered professional engineer or architect.
D. Adequate drainage paths around structures to guide floodwaters around and away shall be required for any new proposed construction in the AO and AH zones. (Ord. 2009-55 § 2, 2010; Ord. 92-001 § 7, 1992. 2004 Code § 15.04.115.)