A. In all areas of special flood hazards, the following standards are required:
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; and
b. All manufactured homes shall meet the anchoring standards of § 8.22.230.B.
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. All new construction, substantial improvement and other proposed new development 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; and
d. Within Zones AH or AO, adequate drainage paths shall be constructed around structures on slopes to guide floodwaters around and away from proposed structures.
3. Elevation and flood-proofing.
a. Residential construction.
i. Residential construction, new or substantial improvement, shall have the lowest floor, including basement;
(a) In an AO Zone, elevated to or above the regulatory flood elevation, or elevated at least 2 feet above the highest adjacent grade if no depth number is specified.
(b) In an A Zone where a BFE has not been determined, elevated to or above the regulatory flood elevation or be elevated in accordance with the criteria developed by the Director of the Arizona Department of Water Resources.
(c) In Zones AE, AH and A1-30, elevated to or above the regulatory flood elevation.
ii. Upon completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, and verified by the community's building inspector to be properly elevated. Such certification and verification shall be provided to the Floodplain Administrator.
b. Nonresidential construction.
i. Nonresidential construction, new or substantial improvement, shall either be elevated to conform with § 8.22.190.C.1, or together with attendant utility and sanitary facilities:
(a) Be flood-proofed below the elevation recommended under § 8.22.190.C.1 so that 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 section are satisfied. Such certification shall be provided to the Floodplain Administrator.
4. Flood openings.
a. All new construction and substantial improvements 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 for the entry and exit of floodwaters. Designs for meeting this requirement must meet or exceed the following criteria:
i. Have a minimum of 2 openings, on different sides of each enclosed area, having a total net area of not less than 1 square inch for every square foot of enclosed area subject to flooding. The bottom of all openings shall be no higher than 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; or
ii. If it is not feasible or desirable to meet the openings criteria stated above, a registered engineer or architect may design and certify the openings.
6. Garages and low cost accessory structures.
a. Attached garages.
i. 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 flood waters. See § 8.22.190.C.3. Areas of the garage below the regulatory flood elevation must be constructed with flood resistant materials. See § 8.22.190.B.
ii. A garage attached to a nonresidential structure must meet the above requirements or be dry flood-proofed.
b. Detached garages and accessory structures.
i. "Accessory structure" used solely for parking (2 car detached garages or smaller) or limited storage (small, low-cost sheds), as defined in § 8.22.050, 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 flood-proofed to or above the regulatory flood elevation;
(e) The accessory structure must comply with floodplain encroachment provisions in § 8.22.250; and
(f) The accessory structure must be designed to allow for the automatic entry of flood waters in accordance with § 8.22.190.C.3.
ii. Detached garages and accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in § 8.22.190.
(Ord. 08-935, passed 8-12-2008; Ord. 91-364, § 1 (part), passed - -1991)