§ 23.07.066. Construction Standards.

a.

Construction, general:

(1)

No construction or grading is to limit the capacity of the floodway or increase flood heights on existing structures unless the adverse effect of the increase is rectified to the satisfaction of the Director of Public Works. In no case shall flood heights be increased above that allowed under the Federal Flood Insurance Program.

(2)

Structures shall be anchored to prevent collapse, lateral movement or flotation that could result in damage to other structures or restriction of bridge openings and narrow sections of the stream or river.

(3)

Service facilities such as electrical and heating equipment are to be floodproofed or constructed at minimum of one-foot above the 100-year storm flood profile level for the site.

(4)

Water supply and sanitary sewage systems shall be designed to minimize infiltration of flood waters into the system and discharge from systems into flood waters.

(5)

On-site waste disposal systems shall be located to avoid their being impaired or contaminated during flooding.

(6)

All buildings or structures shall be located landward of mean high tide.

(7)

Residential, commercial and industrial development shall be prohibited outside of urban and village reserve lines.

(8)

Whenever a watercourse is to be altered or relocated, the Department of Planning and Building shall notify adjacent communities and the California Department of Water Resources and evidence of such notification shall be sent to the Federal Insurance Administration.

(9)

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:

(i)

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.

(ii)

The bottom of all openings shall be no higher than one foot above grade.

(iii)

Openings may be equipped with screens, louvers, valves or other coverings or devices provided that they permit the automatic entry and exit of flood waters.

(10)

On the basis of structural plans and the depth analysis, the ground floor of all structures is to be constructed at a minimum of one-foot above the 100-year storm flood profile level. Within any AO zone on the Flood Insurance Rate maps, this elevation shall be determined by adding one foot to the depth number specified. If no depth is specified, structures shall be elevated a minimum of two feet above adjacent natural grade.

(11)

Non-residential construction shall either be elevated in conformance with Section 23.07.066a(10) above, or together with attendant utility and sanitary facilities, be elevated a minimum of two feet above the highest adjacent grade and be floodproofed to a minimum of one-foot above the 100-year storm flood profile level. Examples of floodproofing include, but are not limited to:

(i)

Installation of watertight doors, bulkheads, and shutters.

(ii)

Reinforcement of walls to resist water pressure.

(iii)

Use of paints, membranes, or mortars to reduce seepage through walls.

(iv)

Addition of mass or weight to structure to resist flotation.

(v)

Armor protection of all fill materials from scour and/or erosion.

(12)

All structures subject to inundation shall use flood resistant materials up to one foot above base flood elevation.

b.

Storage and processing: The storage or processing of materials that in time of flooding are buoyant, flammable, or explosive; that could be injurious to human, animal, or plant life; or that may unduly affect the capacity of the floodway or unduly increase flood heights is not permitted. Storage of other material or equipment may be allowed if not subject to major damage by floods and if firmly anchored to prevent flotation, or if readily removable from the area within the time available after flood warning.

c.

Coastal High Hazard areas. The following requirements shall apply to new structures or any improvement / repair to an existing structure as specified in Section 23.07.066 in areas identified as having special flood hazards extending from offshore to the inland limit of a primary frontal dune along an open coast and any other area subject to high velocity waters including coastal and tidal inundation or tsunamis as established on the maps identified in subsection 23.07.060 of this title:

(1)

All buildings or structures 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 to or above the base flood elevation 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 used 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.

(3)

All buildings or structures shall have the space below the lowest floor free of obstructions or constructed with breakaway walls. 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)

Man-made alteration of sand dunes that would increase potential flood damage is prohibited.

(6)

The Director of Planning and Building and/or the Public Works Director shall obtain and maintain the following records.

(i)

Certification by a registered engineer or architect that a proposed structure complies with Subsection D.3.a

(ii)

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

d.

Certification of Compliance. The following certifications shall be filed with the Building Official prior to final building inspection:

(1)

Upon completion of any structure within a flood hazard combining designation, compliance with elevation requirements shall be certified by a registered civil engineer or licensed land surveyor. Such certification shall include as a minimum the elevation of the lowest floor. If the structure has been floodproofed in conformance with Section 23.07.066a(11) above, the certification shall include the elevation to which the structure has been floodproofed. Elevations shall be based on the National Geodetic Vertical Datum of 1929.

(2)

Where floodproofing is used, a registered civil engineer or architect shall certify that the floodproofing methods are adequate to withstand the flood depths, pressures, velocities, impact and uplift forces and other factors associated with the 100-year flood.

(3)

Compliance with the structural design requirements within Coastal High Hazard areas stated in Section 23.07.066c shall be certified by a registered civil engineer or architect.

e.

Exceptions to construction standards. The standards of this section may be waived or modified by the Board of Supervisors through the variance procedure set forth in Code of Federal Regulations, Title 44, Chapter 1, Section 60.6, instead of through the adjustment process described in Section 23.01.044 of this title. Requests for such waivers or modifications shall be filed with County Public Works for processing. Procedures for the granting of variances under Title 14 are available from the County Public Works Department.

[Amended 1995, Ord. 2715; 1995, Ord. 2740; 2003, Ord. 3025]

f.

Waiver of rights to future armoring. Where applicant's geologic assessment/wave run-up studies determine that the new or improved development is sited such that it will not need a shoreline protective device for the life of the structure, the applicants shall waive their rights to a future shoreline protective device.

[Added 2006, Reso. 2006-6]

e.

Tsunami Inundation Zone. Where feasible, development shall be sited outside of potential tsunami inundation zones, even if not currently designated FH. A Registered Civil Engineer with coastal experience shall make a determination, through examination of the most current tsunami inundation and run-up maps or a wave run-up analysis, whether the site is subject to inundation during a tsunami, pursuant to the criteria of Section 23.07.064b. If it is not feasible to site development outside of tsunami inundation zone, new development shall be in conformance with all provisions set forth in Section 23.07.066(c).

[Added 2006, Reso. 2006-6]