Tiburon Municipal Code Art. III Standards of Construction

In all areas of special flood hazards the following standards are required as set out in sections 13D-13 through 13D-20.

(Ord. No. 460 N.S., § 3 (part))

(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 13D-18.

(Ord. No. 460 N.S., § 3 (part))

(a) All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage and using methods and practices that minimize flood damage.

(b) 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.

(Ord. No. 460 N.S., § 3 (part))

(a) New construction and substantial improvement of any structure shall have the lowest floor, including the basement, elevated at least two feet above the base flood elevation.

(b) Nonresidential construction shall either be elevated in conformance with subsection (a) of this section or together with attendant utility and sanitary facilities:

(1) Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

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

(3) Be certified by a registered professional engineer or architect that the standards of this section are satisfied. Such certifications shall be provided to the floodplain administrator.

(c) Require, for all new construction and substantial improvements, that fully enclosed areas below the lowest floor that 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:

(1) Either a minimum of two openings having a total new area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided. 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 floodwaters; or

(2) Be certified to comply with a local floodproofing standard approved by the Federal Insurance Administration.

(d) Manufactured homes shall also meet the standards in section 13D-18.

(Ord. No. 460 N.S., § 3 (part); Ord. No. 499 N.S., § 2(A))

(a) All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and discharge from systems into floodwaters.

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

(Ord. No. 460 N.S., § 3 (part))

(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 final pad elevation shall be certified by a registered professional engineer or surveyor and provided to the floodplain administrator.

(c) All subdivision proposals and other proposed development shall be consistent with the need to minimize flood damage.

(d) All subdivision proposals and other development 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 and other proposed development shall provide adequate drainage to reduce exposure to flood hazards.

(f) All new subdivision proposals and other proposed development, including proposals for manufactures home parks and subdivisions, greater than fifty lots or five acres, whichever in the lesser, shall:

(1) Identify the special flood hazard areas (SFHA) and base flood elevations (BFE).

(2) Identify the elevations of lowest floors of all proposed structures and pads on the final plans.

(3) If the site is filled above the base flood elevation, the following as-built information for each structure shall be certified by a registered civil engineer or licensed land surveyor and provided as part of an application for a letter of map revision based on fill (LOMR-F) to the floodplain administrator:

a. Lowest floor elevation.

b. Pad elevation.

c. Lowest adjacent grade

(Ord. No. 460 N.S., § 3 (part)

(Ord. No. 543 N.S., §§ 2.E., 11-7-2012)

(a) All manufactured homes that are placed or substantially improved within zone A, AE, AH, AO, AR, A1-30, or A99 on the community's flood insurance rate map, on sites located outside of a manufactured home park or subdivision, in a new manufactured home park or subdivision, in an expansion to an existing manufactured home park or subdivision, or in an existing 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 at least two feet above the base elevation and be securely anchored 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 within zone V , V1-30, or VE on the community's flood insurance rate map will meet the requirements of subsection 13D-18(a).

(c) All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within zone A, AE, AH, AO, AR, A1-30, A99, V, V1-30, or VE on the community's flood insurance rate map that are not subject to the provisions of subsection 13D-18(a) will be elevated so that either the:

(1) Lowest floor of the manufactured home is at least two feet above the base flood elevation, or

(2) The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty-six inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

(Ord. No. 460 N.S., § 3 (part); Ord. No. 499 N.S., § 2(B)(C))

(Ord. No. 543 N.S., §§ 2.F., 11-7-2012)

(a) All recreational vehicles placed on sites within zone A, AE, AH, AO, AR, A1-30, A99, V or VE on the community's flood insurance rate map will comply with at least one of the following:

(1) Be on the site for fewer than one hundred eighty consecutive days; or

(2) 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

(3) Meet the permit requirements of section 13D-9 of this chapter and the elevation and anchoring requirements for manufactured homes in section 13D-18.

(Ord. No. 460 N.S., § 3 (part))

(Ord. No. 543 N.S., §§ 2.G., 11-7-2012)

(a) Floodways. Located within areas of special flood hazard established in section 13D-4 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

(1) Prohibit encroachments, including fill, new construction, substantial improvement, and other new development unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in the base flood elevation during the occurrence of the base flood discharge.

(2) If subsection 13D-20(a)(1) is satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of article III of this chapter.

(b) Coastal high hazard areas. Within coastal high hazard areas, zones V, V1-30, and VE, as established under section 13D-4, the following standards shall apply:

(1) All new residential and non-residential construction, including substantial improvement/damage, shall be elevated on adequately anchored pilings or columns and securely anchored to such pilings or columns so that the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated to or above the base flood level. The pile or column foundation and structure attached thereto is anchored to resist flotation, collapse, and lateral movement due to the effects of wind and water loads acting simultaneously on all building components. Water loading values shall be those associated with the base flood. Wind loading values used shall be those required by applicable state or local building standards.

(2) All new construction and other development shall be located on the landward side of the reach of mean high tide, unless it complies with all standards of the flood resistant construction provisions as set forth in the current California Building Code and/or the current California Residential Code for construction in coastal high hazard areas.

(3) All new construction and substantial improvement shall have the space below the lowest floor free of obstructions or constructed with breakaway walls as defined in section 13D-2 of this chapter. Such enclosed space shall not be used for human habitation and will be usable solely for parking of vehicles, building access or storage.

(4) Fill shall not be used for structural support of buildings.

(5) Manmade alteration of sand dunes which would increase potential flood damage is prohibited.

(6) The floodplain administrator shall obtain and maintain the following records:

a. Certification by a registered engineer or architect that a proposed structure complies with section 13D-20; and

b. The elevation (in relation to mean sea level) of the bottom of the lowest horizontal structural member of the lowest floor (excluding pilings or columns) of all new and substantially improved structures, and whether such structures contain a basement.

(Ord. No. 460 N.S., § 3 (part))

(Ord. No. 543 N.S., §§ 2.H., 11-7-2012)