Chapter 13.92
PROVISIONS FOR FLOOD HAZARD REDUCTION
Sections:
13.92.010 Requirements for buildings and structures in flood hazard areas.
13.92.020 Standards for utilities.
13.92.030 Standards for subdivisions.
13.92.040 Standards for manufactured/mobile homes.
13.92.050 Detached garages and accessory storage structures.
13.92.060 Standards for recreational vehicles.
13.92.010 Requirements for buildings and structures in flood hazard areas.
Applications for building and structures within the scope of the building code that are proposed in flood hazard areas shall comply with the applicable requirements of the current edition of the building code and ASCE 24.
In all areas of special flood hazards, the following standards are required:
A. Anchoring.
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 13.92.040.
B. Construction Materials and Methods.
1. All new construction and substantial improvements shall be constructed with materials 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 zones AH or AO adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.
C. Elevation and Floodproofing.
1. Residential property which is either newly constructed or substantially improved shall have the lowest floor, including the basement:
a. In an AO zone, elevated in accordance with the current edition of the building code and ASCE 24.
b. In an A zone, elevated to or above the base flood elevation, in accordance with the current edition of the building code and ASCE 24.
c. In all other zones, elevated in accordance with the current edition of the building code and ASCE 24.
Upon completion of the structure, the elevation of the lowest floor (including the basement) shall be certified by a registered professional engineer or surveyor, or verified by the building inspector to the property elevated. Such certification or verification shall be provided to the director of public works.
2. Nonresidential construction shall either be elevated in conformance with subsection (C)(1) of this section, 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 certification shall be provided to the director of public works.
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 the entry and exit of floodwater. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or 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 to comply with local floodproofing standards approved by the Federal Insurance Administration Federal Emergency Management Agency.
4. Manufactured homes shall also meet the standards in Section 13.92.040. (Ord. 2022-10 § 2, 2022; Ord. 98-8 § 26, 1998; Ord. 711 (part), 1988: Ord. 649 § I (part), 1982)
13.92.020 Standards for utilities.
A. All new and replaced sanitary sewer facilities, private sewage treatment plants (including all pumping stations and collector systems) and on-site waste disposal systems shall be designed in accordance with Chapter 7, ASCE 24, to minimize or eliminate infiltration of floodwaters into the facilities and discharge from the facilities into floodwaters, and impairment of the facilities and systems.
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 lowest floor and pad elevations shall be certified by a registered professional engineer or surveyor and shall be provided to the director of public works. The certified project engineer shall apply for and secure letters of map revision for all newly constructed homes in new subdivisions, including payment of FEMA fees.
C. All subdivision proposals and other proposed new developments shall include within such proposals base flood elevation data.
D. Utility and Miscellaneous Group U. Utility and miscellaneous Group U includes buildings that are accessory in character and miscellaneous structures not classified in any specific occupancy in the building code, including, but not limited to, agricultural buildings, aircraft hangars (accessory to a one- or two-family residence), barns, carports, fences more than six feet (one thousand eight hundred twenty-nine millimeters) high, grain silos (accessory to a residential occupancy), greenhouses, livestock shelters, private garages, retaining walls, sheds, stables, and towers. In addition to the building code requirements for fire and life safety, the following shall apply to utility and miscellaneous Group U buildings and structures in flood hazard areas:
1. New construction and substantial improvement of such buildings and structures shall be anchored to prevent flotation, collapse or lateral movement resulting from flood loads, including the effects of buoyancy, during conditions of the design flood.
2. New construction and substantial improvement of such buildings and structures, when fully enclosed by walls, shall be elevated such that the lowest floor, including basement, is elevated to or above the design flood elevation in accordance with ASCE 24 or shall be dry floodproofed in accordance with ASCE 24.
3. Unless dry floodproofed, fully enclosed areas below the design flood elevation shall be constructed in accordance with ASCE 24 and limited to parking, storage, and building access.
4. When fully enclosed by walls, flood openings shall be installed in accordance with ASCE 24.
5. Flood damage-resistant materials shall be used below the design flood elevation.
6. Mechanical, plumbing and electrical systems, including plumbing fixtures, shall be built above the design flood elevation or meet the requirements of ASCE 24, except that minimum electric service required to address life safety and electric code requirements is permitted below the design flood elevation provided it conforms to the provisions of the electrical part of the building code for wet locations. (Ord. 2022-10 § 2, 2022; Ord. 98-8 § 27, 1998; Ord. 711 (part), 1988: Ord. 649 § 1 (part), 1982)
13.92.030 Standards for subdivisions.
A. All new subdivisions proposals and other proposed development, including proposals for manufactured home parks and subdivisions, greater than fifty lots or five acres, whichever is 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 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.
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 shall be provided to the director of the public works. The certified project engineer shall apply for and secure letters of map revision for all newly constructed homes in new subdivisions, including payment of FEMA fees.
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 subdivisions shall provide adequate drainage to reduce exposure to flood hazards.
F. New and replacement water supply systems to be designed to minimize or eliminate infiltration of floodwaters into the system shall be required within flood-prone areas.
G. Adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures shall be required within zones AH and AO. (Ord. 2022-10 § 2, 2022; Ord. 2009-02 § 3, 2009; Ord. 96-3 § 4, 1996; Ord. 711 (part), 1988: Ord. 649 § 1 (part), 1982)
13.92.040 Standards for manufactured/mobile homes.
A. All manufactured homes that are placed or substantially improved 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 home park or subdivision; or (4) in an existing manufactured home park or subdivision upon which a manufactured home has incurred “substantial damage” as the result of a flood, shall:
1. Within zones A1-30, AH, and AE on the community’s flood insurance rate map, 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 to be placed or substantially improved on sites in an existing manufactured home park or subdivision within zones A1-30, AH or AE on the community’s flood insurance rate map that are not subject to the provisions of subsection (A) of this section shall be elevated so that either:
1. The lowest floor of the manufactured home is at or above the base flood elevation; or
2. The manufactured home’s 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 securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
Upon completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered civil engineer or licensed land surveyor, and verified by the community building inspector to be properly elevated. Such certification and verification shall be provided to the floodplain administrator.
C. Protection of Mechanical Equipment and Outside Appliances. Mechanical equipment and outside appliances shall be elevated to or above the lowest floor or bottom of the lowest horizontal structural member of the manufactured home, as applicable to the flood hazard area.
Exception. Where such equipment and appliances are designed and installed to prevent water from entering or accumulating within their components and the systems are constructed to resist hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during the occurrence of flooding up to the elevation required by Section 13.92.070, as applicable, the systems and equipment shall be permitted to be located below that elevation.
Electrical wiring systems shall be permitted below the design flood elevation provided they conform to the provisions of NFPA 70 (National Electric Code).
D. All manufactured homes installed in flood hazard areas shall be installed by an installer that is licensed pursuant to the Business and Professions Code and shall comply with the requirements of the Department of Housing and Community Development (HCD) and the requirements of these regulations. In addition to permits pursuant to these regulations, permits from the HCD are required where the HCD is the enforcement agency for installation of manufactured homes.
E. Enclosures. Fully enclosed areas below elevated manufactured homes shall comply with the enclosed area requirements of Section R322 of the Residential Code (CCR Title 24 Part 2.5).
F. Flood Damage-Resistant Materials. Materials below elevated manufactured homes shall comply with the flood-damage resistant materials requirements of Section R322 of the Residential Code (CCR Title 24 Part 2.5). (Ord. 2022-10 § 2, 2022; Ord. 2009-02 § 4, 2009; Ord. 98-8 § 28, 1998; Ord. 96-3 § 5, 1996)
13.92.050 Detached garages and accessory storage structures.
Detached garages and accessory storage structures used only for parking or storage are permitted below the base flood elevation provided the garages and accessory storage structures:
A. Are one story and not larger than six hundred square feet in area when located in special flood hazard areas.
B. Are anchored to resist flotation, collapse or lateral movement resulting from flood loads.
C. Have flood openings in accordance with the building code.
D. Have flood damage-resistant materials used below the base flood elevation.
E. Have mechanical, plumbing and electrical systems, including plumbing fixtures, elevated to or above the base flood elevation. (Ord. 2022-10 § 2, 2022)
13.92.060 Standards for recreational vehicles.
All recreational vehicles placed on sites within zone A1-30, AH or AE on the community’s flood insurance rate map will either:
A. Be on the site for fewer than one hundred eighty consecutive days; or
B. 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 by no more than quick-disconnect utilities and/or security device, and has no permanently attached additions; or
C. Meet the permit requirements of Section 13.88.010 and the elevation and anchoring requirements for manufactured homes in Section 13.92.040(A). (Ord. 2022-10 § 2, 2022; Ord. 2009-02 § 5, 2009; Ord. 98-8 § 29, 1998; Ord. 96-3 § 6, 1996. Formerly 13.92.050)
13.92.070 Floodways.
Located within areas of special flood hazard established pursuant to Section 13.84.020 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:
A. Encroachments, including fill, new construction, substantial improvement and other new development within floodways is prohibited 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.
B. If the requirements of subsection (A) of this section are satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of this chapter. (Ord. 2022-10 § 2, 2022; Ord. 98-8 § 30, 1998. Formerly 13.92.060)