17-5-1 Standards of Construction.
In all regulatory floodplain areas, the following standards are required:
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 Section 17-5-5(B).
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, substantial improvements, and other proposed new development shall be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment, as well as 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. Within Zone AH or AO, adequate drainage paths around structures on slopes are required to guide floodwaters around and away from proposed structures.
C. Elevation and Flood-Proofing.
1. New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated at or above the regulatory flood elevation. In areas without a detailed study but within regulatory floodplain boundaries, the applicant shall have an Arizona registered professional engineer prepare a detailed study to determine the depth of the base flood. Nonresidential structures may meet the standards in subsection (C)(3) of this section. Upon the completion of the structure, the elevation of the lowest floor, including basement, shall be certified by an Arizona registered professional engineer or an Arizona registered professional land surveyor, and provided to the Floodplain Administrator and the Town Building Official.
2. New construction and substantial improvement of any structure in Zone AO shall have the lowest floor, including basement, higher than the highest adjacent grade at least one (1) foot higher than the depth number on the FIRM, or at least two (2) feet if no depth number is specified. Nonresidential structures may meet the standards in subsection (C)(3) of this section. Upon completion of the structure an Arizona registered professional engineer or Arizona registered professional land surveyor shall certify to the Floodplain Administrator that the elevation of the structure meets this standard.
3. Nonresidential construction and new and substantial improvement of any structure shall either be elevated in conformance with subsections (C)(1) and (2) of this section, or together with attendant utility and sanitary facilities:
a. Be flood-proofed so that below the regulatory flood elevation 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 an Arizona registered professional engineer or an Arizona registered professional architect that the standards of this subsection are satisfied. Such certifications shall be provided to the Floodplain Administrator and the Town Building Official.
4. Require, for all new construction and substantial improvements of nonresidential structures, that have fully enclosed areas below the regulatory flood elevation that are usable solely for parking of vehicles, building access, or storage in an area other than a basement, and which are subject to flooding, shall be constructed of flood resistant materials to the regulatory flood elevation, have all service facilities elevated at or above the regulatory flood elevation, and 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 an Arizona registered professional engineer or an Arizona registered professional architect or meet or exceed the following minimum criteria:
a. A minimum of two (2) openings, on different sides of each enclosed area, shall be provided having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding. Smaller engineered openings may be allowed if the design is supported by a certification report issued by ICC-ES (International Code Council Evaluation Service), or an equivalent product certification organization.
b. The bottom of all openings shall be no higher than one (1) foot above grade.
c. Openings may be equipped with screens, louvers, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.
5. Manufactured homes shall meet the standards in Section 17-5-5. ((O)21-06, 11/17/2021; (O)17-04, 04/05/2017; (O)05-35, 10/05/2005)