9-71 Provisions for Flood Hazard Reduction

Sec. 9-71. Provisions for Flood Hazard Reduction.

9-71.1. Standards of Construction.In all areas of special flood hazards the following standards are required:

1.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.

2.All manufactured homes shall meet the anchoring standards of Section 9-71.4.

1.All new construction and substantial improvements shall be constructed with flood resistant materials as specified in FEMA Technical Bulletin TB2-93, and utility equipment resistant to flood damage.

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

3.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.

4.Require within Flood Hazard Zones AH or AO adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures.

C.Elevation and Floodproofing see Section 9-69 definitions for “basement”, “lowest floor”, “new construction”, “substantial damage”, and “substantial improvement”.

1.All new construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to or above the base flood elevation. Nonresidential structures may meet the standards in Section 9-71.1.C(3). Upon the completion of the structure the elevation of the lowest floor including basement shall be certified by a registered and professional engineer or surveyor, or verified by the community building inspector to be properly elevated. Such certification or verification shall be provided to the Floodplain Administrator.

2.New construction and substantial improvement of any structure in Zone AO shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM, or at least two feet if no depth number is specified. Nonresidential structures may meet the standards in Section 9-71.1.C(3). Upon the 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 community building inspector to be properly elevated. Such certification or verification shall be provided to the Floodplain Administrator.

3.Nonresidential, new or substantial improvements shall either be elevated in conformance with Section 9-71.1.C(1) or (2) or together with attendant utility and sanitary facilities:

(a)be floodproofed so that below the base flood level 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 subsection are satisfied. Such certifications shall be provided to the Floodplain Administrator.

4.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 TBI-93 and TB 7-93, and must exceed the following minimum criteria:

(a)Have a minimum of two openings having a total net area of net less than one square inch for every square foot of enclosed area subject to flooding shall be provided. The bottom of aH 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 floodwaters; or

(b)be certified by a registered professional engineer or architect.

5.Manufactured homes shall also meet the standards in Section 9-71.4.

A.All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the system and discharge from systems into flood waters.

B.On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

A.All preliminary subdivision proposals shall identify the flood hazard area and the elevation of the base flood.

B.All final subdivision plans will provide the elevation of proposed structure(s) and pads. If the site is filled above the base flood, the lowest floor and pad elevation shall be certified by a registered professional engineer or surveyor and provided to the Floodplain Administrator.

C.All subdivision proposals shall be consistent with the need to minimize flood damage;

D.All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical, and water systems located and constructed to minimize flood damage;

E.All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage.

A.All manufactured homes that are placed or substantially improved within Zones A1-30, AH, and AE on the community’s Flood Insurance Rate Map on sites located:

1.outside of a manufactured home park or subdivision;

2.in a new manufactured home park or subdivision;

3.in an expansion to an existing manufactured homepark or subdivision; or

4.in an existing manufactured home park or subdivision on a site upon which a manufactured home has incurred “substantial damage” as the result of a flood, shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

B.All manufactured homes that are placed or substantially improved on sites located with Zones V1-30, V, and VE on the community’s Flood Insurance Rate map will meet the requirements of Section 9-71.4.A and Section 9-71.5.

C.All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within Zones A1-30, AH, AE, V1-30, V and VE on the community’s Flood insurance Rate Map that are not subject to the provisions of paragraph 9-71.4.A will be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement, and elevated so that the lowest floor of the manufactured home is at or above the base flood elevation (the State of California recommends at least two feet above the base flood elevation) and be securely anchored to a permanent foundation system to resist flotation, collapse or lateral movement.

D.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 community building inspector to be properly elevated. Such certification and verification shall be provided to the Floodplain Administrator.

A.All recreational vehicles placed on sites within Zones A1-30, AH, and AE on the community’s Flood Insurance Rate Map will either:

1.be on the site for fewer than 180 consecutive days, and be fully licensed and ready for highway use - a recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick-disconnect type utilities and security devices, and has no permanently attached additions, or

2.meet the permit requirements of Section 9-70 of this ordinance and the elevation and anchoring requirements for manufactured homes in Section 9-71.4.A.

B.Recreational vehicles placed on sites within Zones V1-30, V. and VE on the community’s Flood Insurance Rate Map will meet the requirements of Section 9-71.4.1 A and Section 9-71.5.