A. Residential construction, new or substantial improvement, shall have the lowest floor, including basement:
1. In an AO Zone, elevated to or above the regulatory flood elevation, or elevated at least two feet above the highest adjacent grade if no depth number is specified;
2. In an A Zone where a base flood elevation has not been determined, elevated to or above the regulatory flood elevation, or elevated in accordance with the criteria developed either by FEMA or the Director of the Arizona Department of Water Resources;
3. In Zone AE, elevated to or above the regulatory flood elevation.
B. Upon completion of the structure and prior to occupancy, an elevation certificate indicating the elevation of the lowest floor, including basement, shall be certified by a registered, professional engineer or surveyor. The elevation certificate shall be provided to the floodplain administrator.
C. All new construction and substantial improvements with fully enclosed areas below the lowest floor that are subject to flooding (excluding basements) and areas that are usable solely for parking of vehicles, building access or storage, 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 be certified by a registered, professional engineer or architect to meet or exceed the following minimum criteria:
1. A minimum of two openings, on differing sides of each area, 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;
2. The bottom of an openings shall be no higher than one foot above grade;
3. Openings may be equipped with screens, louvers, valves, or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters.
If it is not feasible or desirable to meet the openings criteria stated above, alternatively a registered, engineer or architect may design and certify the openings.
D. Manufactured homes shall meet the standards of Section 15.40.760.
E. Garages and accessory storage buildings shall meet or exceed the following minimum criteria:
1. A garage attached to a residential structure, constructed with the garage floor slab below the regulatory flood elevation, must be designed to allow for the automatic entry of floodwaters as set forth in subsection 15.40.750.C. Areas of the garage below the regulatory flood elevation must be constructed with flood-resistant materials.
2. A garage attached to a nonresidential structure must meet the above requirements or be dry floodproofed.
3. A low-cost and small accessory structure used solely for parking and/or storage may be constructed such that its floor is below the regulatory flood elevation, 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 regulatory flood elevation 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 regulatory flood elevation;
e. The accessory structure must comply with floodway encroachment provisions in Article V.
(Ord. 1397.15.22 § 1 (part), 2019; Ord. 1397.15.21 § 1 (part), 2007; prior code § 17-5-1.3)