§ 82-28.1002. Standards of construction.

In all areas of special flood hazards, the following standards are required:

(1)

Anchoring.

(a)

All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

(b)

All manufactured homes shall meet the anchoring standards of Section 82-28.1008.

(2)

Construction Materials and Methods.

(a)

All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

(b)

All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

(c)

All new construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

(d)

In zones AH, AO or VO, adequate drainage paths around structures. To guide floodwaters around and away from proposed structures shall be constructed.

(3)

Elevation and Floodproofing.

(a)

New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to or above the base flood elevation plus required freeboard. In the San Francisco Bay Delta Estuarine Region, 0.61 meters (two feet) of freeboard is required. In all other unincorporated areas of the county, 0.30 meters (one-foot) of freeboard is required. Nonresidential structures may meet the standards in Section 82-28.1002(3)(c). Upon the completion of the substructure but prior to completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor, or verified by the building inspector to be properly elevated. Such certification or verification shall be provided to the floodplain administrator.

(b)

New construction and substantial improvement of any structure in zone AH, AO or VO shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in meters (feet) on the FIRM plus required freeboard, or at least 0.61 meters (two feet) if no depth number is specified. In the San Francisco Bay Delta Estuarine Region, 0.61 meters (two feet) of freeboard is required. In all other unincorporated areas of the county, 0.30 meters (one-foot) of freeboard is required. Nonresidential structures may meet the standards in Section 82-28.1002(3)(c). Upon the completion of the substructure but prior to completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor, or verified by the building inspector to be properly elevated. Such certification or verification shall be provided to the floodplain administrator.

(c)

If the difference in elevation between the lowest floor and the ground below the lowest floor is two meters (6.6 feet) or greater, the applicant will provide the floodplain administrator with a deed restriction. This deed restriction will be recorded and will run with the property (not the applicant). This restriction will limit the area below the lowest floor to be used only for building access, storage and parking of vehicles and will not allow this area to be developed into habitable space.

(d)

Nonresidential construction shall either be elevated in conformance with Section 82-28.1002 (3)(a) or (b), or together with attendant utility and sanitary facilities:

(i)

Be floodproofed so that below the base flood level plus freeboard, the structure is watertight with walls substantially impermeable to the passage of water;

(ii)

Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and

(iii)

Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied. Such certification shall be provided to the floodplain administrator; or

(iv)

The floodplain administrator may allow the nonresidential structure to be made "flood resistant." Flood resistant structures shall comply with Section 82-28.1002(3)(e).

(e)

For 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 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 registered professional engineer or architect or meet or exceed the following minimum criteria:

(i)

Have a minimum of two openings with a total net area of not less than 6.45 square centimeters (one square inch) for every 0.09 square meters (one square foot) of enclosed area subject to flooding. The bottom of all openings shall be no higher than 0.3 meter (one foot) above grade. (Openings may be equipped with screens, louvers, valves or other coverings or devices provided that they permit the automatic entry and exit of floodwaters).

(4)

Manufactured homes shall also meet the standards in Section 82-28.1008.

(Ords. 2000-33, 99-35, 96-11, 90-118, 88-50, 87-45).