15.16.150 Standards of construction.
In all areas of special flood hazards 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 15.16.180.
B. Construction materials and methods. All new construction and substantial improvement shall be constructed:
1. With flood resistant materials as specified in FEMA Technical Bulletin TB 2-93, and utility equipment resistant to flood damage;
2. Using methods and practices that minimize flood damage;
3. 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; and if
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 and floodproofing. (See Section 15.16.050 definitions for “basement,” “lowest floor,” “new construction,” “substantial damage” and “substantial improvement.”)
1. Residential construction, new or substantial improvement, shall have the lowest floor, including basement:
a. In an AO zone, 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 above the highest adjacent grade if no depth number is specified;
b. In an A zone, elevated to or above the base flood elevation;
c. In AE, AH, and A1-30 zones, elevated to or above the base flood elevation.
Upon the 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 community building inspector to be properly elevated. Such certification and verification shall be provided to the floodplain administrator.
2. Nonresidential construction, new or substantial improvement, shall either be elevated to conform with Section 15.16.150(C)(1) or together with attendant utility and sanitary facilities:
a. Be floodproofed below the elevation recommended under Section 15.16.150(C)(1) so that the structure is watertight with walls substantially impermeable to the passage of water;
b. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and
c. Be certified by a registered professional engineer or architect that the standards of this section are satisfied. Such certification shall be provided to the floodplain administrator.
3. All new construction and substantial improvement 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 floodwater. Designs for meeting this requirement shall follow the guidelines in FEMA Technical Bulletins TR 1-93 and TR 7-93, and must exceed the following minimum criteria:
a. Have 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. The bottom of all openings shall be no higher than 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 floodwater; or
b. Be certified by a registered professional engineer or architect.
4. Manufactured homes shall also meet the standards in Section 15.16.180. (Ord. 04-02 (part), 2002; Ord. 87-6 § 5.1, 1987)