A. Standards of Construction. The following standards and requirements shall apply in all special flood hazard areas, except in zone A99 or as otherwise indicated below:
1. Anchoring.
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 specified in subsection C of this section.
2. Construction Materials and Methods.
a. All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
b. All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.
c. Within zones AH, AO, or AR/AH adequate drainage paths on slopes shall be required to guide flood waters around and away from proposed structures.
3. Elevation and Floodproofing.
a. New construction and substantial improvement of any structure in zones A, AH, and AE shall have the lowest floor, including basement, elevated one foot above the base flood elevation specified in feet on the FIRM. In flood zone A, the local administrator shall require the applicant to include base flood elevation data prepared and sealed by a California-licensed civil engineer in accordance with currently accepted engineering practices. Studies, analyses, and computations must be submitted in sufficient detail to allow review and approval by the local administrator. The applicant is responsible for the accuracy of data submitted for such determination. Nonresidential structures may meet the standards in subsection (A)(3)(d) of this section.
b. New construction and substantial improvement of any structure in zone AO shall have the lowest floor, including basement, elevated to one foot above the depth number specified in feet on the FIRM at the highest adjacent grade or two feet above the highest adjacent grade if no depth number is specified on the FIRM. Nonresidential structures may meet the standards in subsection A.3.d of this section.
c. Upon the completion of the structure, the elevation of the lowest floor including basement shall be certified by a California-licensed land surveyor or civil engineer to be properly elevated. Such certification shall be provided to the local administrator.
d. Nonresidential construction shall either be elevated in conformance with subsections (A)(3)(a) through (c) of this section, together with attendant utility and sanitary facilities, or shall:
i. Be dry floodproofed below the elevation required for the lowest floor 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 California-licensed civil engineer to be in compliance with the standards of this subsection. Such certification shall be provided to the local administrator.
e. For all new construction and substantial improvements, fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access, or storage, and that are subject to flooding, shall be wet flood-proofed and designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood waters. Designs for meeting this requirement must either:
i. Be certified by a California-licensed civil engineer; or
ii. Meet or exceed the following minimum criteria: Provide a minimum of two openings that are located on different exterior walls of the enclosed area, and have 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 must be no higher than one foot above grade. Openings may be equipped with coverings or devices, such as screens, louvers, or valves, which permit the automatic entry and exit of flood waters. Buildings with more than one enclosed area must have openings on the exterior walls of each enclosed area.
f. To ensure that the areas below the base flood elevation shall be used solely for parking vehicles, limited storage, or access to the building and not be finished for use as human habitation without first becoming fully compliant with the floodplain management regulations in effect at the time of conversion, the local administrator shall:
i. Determine which applications for new construction or substantial improvements have fully enclosed areas below the lowest floor that are five feet or higher;
ii. Require the applicant to enter into a non-conversion agreement in a form acceptable to the local administrator. The agreement shall be recorded with the Sacramento County recorder as a deed restriction; and
iii. Have the authority to inspect any area of a structure below the base flood elevation to ensure compliance upon prior notice of at least seventy-two (72) hours.
g. Manufactured homes shall also meet the standards in subsection (A)(3)(d) of this section.
h. For elevation and floodproofing requirements in an AR zone, see subsection F of this section.
i. Garages and Other Accessory Structures.
i. Attached Garages.
(A) A garage attached to a residential structure, constructed with the garage floor slab below the base flood elevation, must be wet floodproofed and designed to allow for the automatic entry and exit of flood waters as specified in subsection (A)(3)(e) of this section. Areas of the garage below the base flood elevation must be constructed with flood resistant materials.
(B) A garage attached to a nonresidential structure must meet the above requirements or be dry flood-proofed.
(C) A garage attached to a residential structure may not be built below the highest adjacent grade.
ii. Detached Garages and Other Accessory Structures.
(A) Accessory structures may be constructed such that the floor of the accessory structure is below the base flood elevation, provided the structure is designed and constructed in accordance with the following requirements:
(1) Use of the accessory structure must be limited to parking or limited storage;
(2) The portions of the accessory structure located below the base flood elevation must be built using flood-resistant materials;
(3) The accessory structure must be adequately anchored to prevent flotation, collapse, and lateral movement;
(4) Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the base flood elevation;
(5) The accessory structure must not result in structure flooding (existing or proposed) or cumulative increase to the BFE by more than 1 foot during the occurrence of the base flood as provided in Section 15.104.040(A)(5)(d); and
(6) The accessory structure must be designed to allow for the automatic entry and exit of flood waters in accordance with subsection (A)(3)(e) of this section.
(B) Detached garages and other accessory structures not meeting the above requirements must be constructed in accordance with all applicable standards in subsections (A)(3)(a) through (g) of this section.
(C) A detached garage for a residential structure may not be built below the highest adjacent grade.
j. All new construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities elevated or dry floodproofed one foot above the base flood elevation or one foot above the zone AO depth number specified in feet on the FIRM at the highest adjacent grade, or two feet above the highest adjacent grade if no depth number is specified on the FIRM.
B. Standards for Wet Utilities.
1. All new and replacement water supply and sanitary sewer systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters.
2. On-site septic and well systems shall be located to avoid impairment to the systems or contamination from the systems during flooding as approved by the Sacramento County health department.
C. Standards for Manufactured Homes.
1. All manufactured homes that are placed or substantially improved within zones A, AH, AO, AE, AR, AR/AE, AR/AH, and AR/AO 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, shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated in accordance to the applicable elevation requirements of subsection (A)(3) and/or (F) of this section and shall be securely fastened to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
2. All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within zones A, AH, AO, AE, AR, AR/AE, AR/AH, AR/AO, and AR/A that are not subject to the provisions of subsection (C)(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 complies with the applicable elevation requirements of subsection (A)(3) and/or (F) of this section; 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 thirty-six (36) inches in height above grade.
D. Standards for Recreational Vehicles. All recreational vehicles placed on sites within zones A, AH, AO, AE, AR, AR/AE, AR/AH, AR/AO, and AR/A:
1. Shall meet the requirements of section 15.104.040 and the elevation and anchoring requirements for manufactured homes in subsection C.1 of this section; or
2. Shall not be on the site for more than 180 consecutive days, and shall 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.
E. Floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential, the following provisions apply in any floodway:
1. Encroachments are prohibited, including fill, new construction, substantial improvements, and other development, unless a California-licensed civil engineer certifies that encroachments will not result in any increase in flood levels during the occurrence of the base flood discharge.
2. If subsection (E)(1) is satisfied, all new construction and substantial improvements shall comply with all other applicable flood hazard reduction provisions of this section.
F. AR Zone Areas. Within areas designated as zones AR, AR/AE, AR/AH, AR/AO, or AR/A, the following standards shall apply:
1. Developed Areas. All new construction in areas designated as developed areas shall meet the standards of this section using the lower of either the AR base flood elevation (or flood depth) or the elevation that is three feet above the highest adjacent grade.
2. Areas Not Designated as Developed Areas. All new construction in areas that are not designated as developed areas:
a. Shall meet the standards of this section using the lower of either the AR base flood elevation (or flood depth) or the elevation that is three feet above the highest adjacent grade, where the AR flood depth is equal to or less than five feet above the highest adjacent grade; or
b. Shall meet the standards of this section using the AR base flood elevation, where the AR flood depth is greater than five feet above the highest adjacent grade.
3. Dual Flood Zones.
a. All new construction in areas within zones AR/AE, AR/AH, AR/AO, or AR/A shall meet the standards of this section using the higher of either the applicable AR zone elevation (as determined under subsection (F)(1) or (F)(2) of this section) or the base flood elevation (or flood depth) for the underlying AE, AH, AO, or A zone.
b. All substantial improvements within zones AR/AE, AR/AH, AR/AO, or AR/A shall meet the standards of this section using the base flood elevation (or flood depth) for the underlying AE, AH, AO, or A zone. (Ord. 2023-0020 § 4; Ord. 2017-0038 § 3; Ord. 2011-046 § 2; Ord. 98-022 § 3; prior code § 9.26.1005)