Corona Municipal Code Ch. 18.20 Provisions of Flood Hazard Reduction

In all areas of special flood hazard, the following standards shall be met.

(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 § 18.20.040.

(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) All new construction and substantial improvements within Zones AH, AO or VO shall be provided with adequate drainage paths to guide flood waters around and away from all structures.

(5) The use of breakaway walls must be certified by a registered engineer or architect and shall meet the following requirements:

(a) Breakaway wall collapse shall result from a water load less than that which would occur during the base flood;

(b) The elevated portion of the building shall not incur any structural damage due to the effects of wind and water loads active simultaneously in the event of the base flood; and

(c) The breakaway wall shall have a safe design loading resistance of not less than ten and no more than 20 pounds per square foot.

(C) Elevation and floodproofing.

(1) New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above the BFE. Upon the completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor or verified by the Building Inspector to be properly elevated. The certification or verification shall be provided to the Floodplain Administrator. For special uses excluding any human occupancy, see subsection (C)(4) below.

(2) New construction and substantial improvement of any residential structure in Zone AH, AO or VO shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the Flood Insurance Rate Map, or at least two feet if no depth number is specified. Upon the completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor, or verified by the Building Inspector to be properly elevated. Such certification or verification shall be provided to the Floodplain Administrator.

(3) Nonresidential construction shall either be elevated in conformance with § 18.20.010(C)(1) or (2) or, together with attendant utility and sanitary facilities, shall:

(a) Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water; and

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

(c) Be certified by a registered professional engineer or architect as meeting the standards of subsections (a) and (b) above. Such certification shall be provided to the Floodplain Administrator.

(4) For all new construction and substantial improvements, any fully-enclosed area below the lowest floor that are useable solely for parking of vehicles, building access or storage in an area other than a basement 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 floodwaters. Designs for meeting this requirement shall be certified by a registered professional engineer or architect and shall meet or exceed the following minimum criteria:

(a) 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 shall be provided. 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 floodwaters; or

(b) Compliance with a local floodproofing standard approved by the Federal Insurance Administration.

(5) Manufactured homes shall also meet the standards of this section.

(D) Garages and low cost accessory structures.

(1) Attached garages.

(a) A garage attached to a residential structure, constructed with the garage floor slab below the BFE, must be designed to allow for the automatic entry of flood waters. Areas of the garage below the BFE must be constructed with flood resistant materials.

(b) A garage attached to a nonresidential structure must meet the above requirements or be dry floodproofed. For guidance on below grade parking areas, see FEMA Technical Bulletin TB-6.

(2) Detached garages and accessory structures.

(a) "Accessory structures" used solely for parking (two-car detached garages or smaller) or limited storage (small, low-cost sheds) may be constructed such that its floor is below the BFE, provided the structure is designed and constructed in accordance with the following requirements:

(i) Use of the accessory structure must be limited to parking or limited storage;

(ii) The portions of the accessory structure located below the BFE must be built using flood-resistant materials;

(iii) The accessory structure must be adequately anchored to prevent flotation, collapse and lateral movement;

(iv) Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the BFE;

(v) The accessory structure must comply with floodplain encroachment provisions in § 18.20.050; and

(vi) The accessory structure must be designed to allow for the automatic entry of floodwaters in accordance with § 18.20.010(C).

(b) Detached garages and accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in this section.

(`78 Code, § 18.20.010.) (Ord. 2961 § 7, 2008; Ord. 2290 § 4, 1996; Ord. 1886 § 1 (part), 1988.)

All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into such systems and discharge from such systems into flood waters. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

(`78 Code, § 18.20.020.) (Ord. 1886 § 1 (part), 1988.)

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

(B) All final subdivision plans shall provide the elevation of proposed structures 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.

(C) All subdivision proposals shall be consistent with the need to minimize flood damage and shall provide for the location and construction of public utilities and facilities such as sewer, gas, electrical and water systems so as to minimize flood damage.

(D) All subdivision proposals shall have adequate drainage provided to reduce exposure to flood hazards.

(`78 Code, § 18.20.030.) (Ord. 1886 § 1 (part), 1988.)

(A) All new and replacement manufactured homes and additions to manufactured homes within Zones A1-30, A.H, and AE on the City of Corona’s FIRM shall 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 anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement. An exception is a manufactured home in an existing manufactured home park or subdivision in which a manufactured home has not incurred "substantial damage" as a result of a flood shall be elevated such that the lowest floor of the manufactured home is at or above the base flood elevation, or the chassis shall be supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.

(B) All new and replacement manufactured homes and additions to manufactured homes within Zone AO on the City of Corona’s FIRM shall meet the requirements of division (A) of this section and § 18.20.010(C)(2).

(`78 Code, § 18.20.040.) (Ord. 2290 § 5, 1996; Ord. 1886 § 1 (part), 1988.)

Located within the areas of special flood hazard established in §§ 18.12.010 and 18.12.020 are areas designated as floodways. Since the floodway is an extremely hazardous area (due to the velocity of flood waters which carry debris and the potential for erosion), the following provisions shall apply:

(A) No encroachments, including fill, new construction, substantial improvements and other development shall be allowed 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;

(B) All new construction and substantial improvements which have been certified as provided in division (A) above shall comply with all applicable flood hazard reduction provisions of this chapter.

(`78 Code, § 18.20.050.) (Ord. 1886 § 1 (part), 1988.)

All recreational vehicles placed in Zones Al-30, A.H, and AE on the City of Corona's FIRM will either:

(A) Be on the site for fewer than 180 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 only by quick disconnect type utilities and security devices, and has no permanently attached additions; or

(C) Meet the permit requirements of this section.

(Ord. 2961 § 8, 2008.)