Point Arena Municipal Code Art. V Provisions for Flood Hazard Reduction

In all areas of special flood hazards the following standards are required:

(1) Anchoring.

(a) All new construction and substantial improvements, including manufactured homes 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.

(b) All manufactured homes shall meet the anchoring standards of PAMC 16.10.200.

(2) Construction Materials and Methods. All new construction and substantial improvement, including manufactured homes shall be constructed:

(a) With flood resistant materials and utility equipment resistant to flood damage for areas below the base flood elevation;

(b) Using methods and practices that minimize flood damage;

(c) 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

(d) 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.

(3) Elevation and Floodproofing. (See PAMC 16.10.050, Definitions, for "Basement," "Lowest floor," "New construction," "Substantial damage" and "Substantial improvement.")

(a) Residential construction, new or substantial improvement, shall have the lowest floor, including basement:

(i) In AE, AH, A1-A30 Zones, elevated to at least two feet above the base flood elevation.

(ii) In an AO Zone, elevated above the highest adjacent grade to a height two feet above the depth number specified on the FIRM, or elevated at least four feet above the highest adjacent grade if no depth number is specified;

(iii) In an A Zone, elevated at least two feet above the base flood elevation; said base flood elevation shall be determined by one of the methods in PAMC 16.10.150(2);

(iv) In all other zones, elevated at least two feet above the minimum required 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.

(b) Nonresidential construction, new or substantial improvement, shall either be elevated to conform with subsection (3)(a) of this section or together with attendant utility and sanitary facilities:

(i) Be floodproofed below the elevation recommended under subsection (3)(a) of this section so that the structure is watertight with walls substantially impermeable to the passage of water;

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

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

(c) 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 flood water. 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:

(i) 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 flood water; or

(ii) Be certified by a registered professional engineer or architect.

(d) Manufactured homes shall also meet the standards in PAMC 16.10.200.

(Ord. 172 § 5.1, 1999; Ord. 231 § 1, 2017.)

(1) All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate:

(a) Infiltration of flood waters into the systems; and

(b) Discharge from the systems into flood waters.

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

(Ord. 172 § 5.2, 1999; Ord. 231 § 1, 2017.)

(1) All preliminary subdivision proposals shall identify the special flood hazard area and the elevation of the base flood.

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

(3) All subdivision proposals shall be consistent with the need to minimize flood damage.

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

(5) All subdivisions shall provide adequate drainage to reduce exposure to flood hazards.

(Ord. 172 § 5.3, 1999; Ord. 231 § 1, 2017.)

(1) All manufactured homes that are placed or substantially improved, within Zones A1-A30, AH, and AE on the community's Flood Insurance Rate Map, on sites located:

(a) Outside of a manufactured home park or subdivision;

(b) In a new manufactured home park or subdivision;

(c) In an expansion to an existing manufactured home park or subdivision; or

(d) 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;

(2) All manufactured homes that are placed or substantially improved on sites located within Zones V1-V30, V, and VE on the community's Flood Insurance Rate Map will meet the requirements of subsection (1) of this section and PAMC 16.10.230.

(3) All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within Zones A1-A30, AH, AE, V1-V30, V, and VE on the community's Flood Insurance Rate Map that are not subject to the provisions of subsection (1) of this section will be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement, and be elevated so that either:

(a) The lowest floor of the manufactured home is at or above the base flood elevation; or

(b) The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade.

(Ord. 172 § 5.4, 1999; Ord. 231 § 1, 2017.)

(1) All recreational vehicles placed on sites within Zones A1-A30, AH, and AE on the community's Flood Insurance Rate Map will either:

(a) 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

(b) Meet the permit requirements of Article IV of this chapter and the elevation and anchoring requirements for manufactured homes in PAMC 16.10.200(1).

(2) Recreational vehicles placed on sites within Zones V1-V30, V, and VE on the community's Flood Insurance Rate Map will meet the requirements of subsection (1) of this section and PAMC 16.10.230.

(Ord. 172 § 5.5, 1999; Ord. 231 § 1, 2017.)

Since floodways are an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

(1) Until a regulatory floodway is adopted, no new construction, substantial development, or other development (including fill) shall be permitted within Zones A1-A30 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 of Point Arena.

(2) Within an adopted regulatory floodway, the city of Point Arena shall prohibit encroachments, including fill, new construction, substantial improvements, and other development, unless certification by a registered civil engineer is provided demonstrating that the proposed encroachment shall not result in any increase in flood levels during the occurrence of the base flood discharge.

(3) If subsections (1) and (2) are satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of Article 5 of this chapter.

(Ord. 172 § 5.6, 1999; Ord. 231 § 1, 2017.)

Within coastal high hazard areas as established under PAMC 16.10.070, the following standards shall apply:

(1) All new residential and nonresidential 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 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 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 new construction and substantial improvement shall have the space below the lowest floor free of obstructions or constructed with breakaway walls as defined in Article II 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 subsection (1) of this section; and

(b) 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 new and substantially improved structures, and whether such structures contain a basement.

(Ord. 172 § 5.7, 1999; Ord. 231 § 1, 2017.)