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 § 15.03.070
B. Construction materials and methods.
1. All new construction and substantial improvements, including manufactured homes, shall be constructed with materials and utility equipment resistant to flood damage for areas below the base flood elevation plus one-foot freeboard.
2. All new construction and substantial improvements, including manufactured homes, shall be constructed using methods and practices that minimize flood damage.
3. All new construction and substantial improvements, including manufactured homes, shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities designed and/or located a minimum of the base flood elevations plus one-foot freeboard, or 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 flood waters around and away from proposed structures.
C. Elevation and floodproofing.
1. New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to or above the base flood elevation plus one-foot freeboard. Nonresidential structures may meet the standards in Subsection 15.03.055 C.3. Upon the completion of the structure the elevation of the lowest floor plus one-foot freeboard, including the basement shall be certified by a registered professional engineer or surveyor, or verified by the community building inspector to be properly elevated. Such certification or verification shall be provided to the Building Official.
2. New construction and Substantial Improvement of any Structure in Zone AH or AO, 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 FIRM plus one-foot freeboard, or at least two (2) feet plus one-foot freeboard if no depth number is specified. Nonresidential structures may meet the standards in Subsection 15.03.055 C.3. 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 community building inspector to be properly elevated. Such certification or verification shall be provided to the Building Official.
3. Nonresidential construction shall either be elevated in conformance with Subsections 15.03.055 C.1. or C.2. or together with attendant utility and sanitary facilities:
a. Be floodproofed so below the base flood level plus one-foot freeboard, 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, the standards of this subsection are satisfied. Such certifications shall be provided to the Building Official.
4. Require, for all new construction and substantial improvements, fully enclosed areas below the lowest floor 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:
a. Either a minimum of two (2) openings have a total net area of not less than one (1) 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 (1) 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. Buildings with more than one enclosed area must have openings on exterior walls for each area to allow flood water to directly enter; or
b. Be certified by a California registered civil engineer or architect to comply with a local floodproofing standard approved by the Federal Insurance Administration.
5. Manufactured homes shall also meet the standards in § 15.03.070.
6. Breakaway walls shall have a safe design loading resistance of not less than ten (10) and no more than twenty (20) pounds per square foot. Use of breakaway walls must be certified by a registered engineer or architect and shall meet the following conditions:
a. Breakaway wall collapse shall result from a water load less than would occur during the base flood; and
b. The elevated portion of the building shall not incur any structural damage due to the effects of wind and water loads acting simultaneously in the event of the base flood.
D. Attached garages.
1. 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 in compliance with Subsection 15.03.055 C.4. Areas of the garage below the BFE must be constructed with flood resistant materials in compliance with Subsection 15.03.055 B.
2. A garage attached to a nonresidential structure must meet the above requirements or be dry floodproofed.
E. Detached garages and accessory structures.
1. Accessory structures used solely for parking (two-car detached garages or smaller) or limited storage (small, low-cost sheds), as defined in § 15.03.015, may be constructed such that its floor is below the base flood elevation (BFE), provided the structure is designed and constructed in accordance with the following requirements:
a. Use of the accessory structure must be limited to parking or limited storage;
b. The portions of the accessory structure located below the BFE must be built using flood-resistant materials;
c. The accessory structure must be adequately anchored to prevent flotation, collapse, and lateral movement;
d. Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the BFE;
e. The accessory structure must comply with floodplain encroachment provisions in Subsection 15.03.080 A.; and
f. The accessory structure must be designed to allow for the automatic entry of flood waters in accordance with Subsection 15.03.055 C.4.a.
2. Detached garages and accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in Subsections 15.03.055 A. through C.
('65 Code, § 9-154.5) (Ord. 2021- 004 § 1 (part))