Oxnard Municipal Code Art. IV Provisions for Flood Hazard Reduction

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

(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 or hydrostatic loads, including the effects of buoyancy.

(2) All manufactured homes shall meet the anchoring standards of this chapter.

(B) Construction materials and methods -

(1) All new construction and substantial improvements shall be constructed with flood resistant materials as specified in FEMA Technical Bulletin TB 2-93 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) 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

(4) Within Zone 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 flood proofing. (See section 18-2 definitions for "basement," "lowest floor," "new construction," "substantial damage," and "substantial improvement.")

(1) The lowest floor, including basement, of a residential construction, new or substantial improvement, shall:

(a) In a Zone AO, be 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. In Zone AO without velocity, the lowest floor shall be elevated above the highest adjacent grade to a height exceeding the depth number specified in feet on the FIRM by at least two feet, or elevated at least four feet above the highest adjacent grade if no depth number is specified.

(b) In a Zone A, be elevated at least two feet above the base flood elevation. Said base flood elevation shall be determined by one of the methods in section 18-21(B).

(c) In all other zones, be elevated at least two feet 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 a city building inspector to be properly elevated. Such certification and verification shall be filed with the floodplain administrator.

(2) Nonresidential construction, new or substantial improvement, shall either be elevated to conform with subsection 18-35(C)(1) or, together with attendant utility and sanitary facilities:

(a) Be flood proofed below the elevation recommended under section 18-35(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 subsection 18-35(C)(2) are satisfied. Such certification shall be filed with 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 TB 1-93 and TB 7-93, and must exceed the following minimum criteria:

(a) Have a minimum of two openings having a total net area of 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 this section.

(`64 Code, Sec. 35-21) (Ord. No. 2426, 2640)

(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) 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) On-site waste disposal systems shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.

(D) All subdivisions shall locate and construct public utilities and facilities such as sewer, gas, electrical, and water systems to minimize flood damage.

(E) All subdivision proposals shall provide adequate drainage to reduce exposure to flood hazards.

(`64 Code, Sec. 35-22) (Ord. No. 2426, 2640)

(A) Located within areas of special flood hazard are areas designated as floodways.

(B) Until a regulatory floodway is adopted, no new construction, substantial development, or other development (including fill) shall be permitted within Zones A1-30 and AE, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other development, will not increase the water surface elevation of the base flood more than one foot at any point within the city.

(C) Because the floodway is an extremely hazardous area due to the velocity of flood waters that carry debris, potential projectiles, and erosion potential, the floodplain administrator shall:

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

(2) If the requirements of subsection (1) above are satisfied, ensure that all new construction and substantial improvements shall comply with all other applicable flood hazard reduction provisions.

(`64 Code, Sec. 35-25) (Ord. No. 2426, 2640, 2989)

Within coastal high hazard areas designated on the effective FIRM, the following standards shall apply:

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

(B) All new construction shall be located on the landward side of the reach of mean high tide.

(C) All new construction and substantial improvements shall have the space below the lowest floor free of obstructions or constructed with breakaway walls. Such temporarily enclosed space shall not be used for human habitation and may be usable solely for parking of vehicles, building access, or storage.

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

(E) Manmade alteration of sand dunes that would increase potential flood damage is prohibited.

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

(1) Certification by a registered engineer or architect that a proposed structure complies with this section; and

(2) 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.

(`64 Code, Sec. 35-26) (Ord. No. 2426, 2640, 2989)

(A) The floodplain administrator shall require permits for proposed construction and other development within all flood-related erosion-prone areas.

(B) The floodplain administrator shall review permit applications to determine whether the proposed site alterations and improvements will be reasonably safe from flood-related erosion and will not cause flood-related erosion hazards or otherwise aggravate the existing hazard.

(C) If a proposed improvement is found to be in the path of flood-related erosion or would increase the erosion hazard, the floodplain administrator shall require that such improvement be relocated or adequate protective measures be taken to avoid aggravating the existing erosion hazard.

(D) Within Zone E on the Flood Insurance Rate Map, a setback is required for all new development from the ocean, lake, bay, riverfront or other body of water to create a safety buffer consisting of a natural vegetative or contour strip. This buffer shall be designated according to the flood-related erosion hazard and erosion rate, in relation to the anticipated "useful life" of structures, and depending upon the geologic, hydrologic, topographic and climatic characteristics of the land. The buffer may be used for suitable open space purposes, such as for agricultural, forestry, outdoor recreation and wildlife habitat areas, and for other activities using temporary and portable structures only.

(Ord. No. 2640)