A. Residential Construction: New construction and substantial improvement of any residential structure shall have the lowest floor (including basement), elevated one-foot (1') above the base flood elevation. A registered professional engineer, architect, or land surveyor shall submit a certification to the floodplain administrator that the standard of this division as proposed in section 11-1-15A.1. is satisfied.
B. Non-Residential Construction: New construction and substantial improvements of any commercial, industrial or other non-residential structure shall either have the lowest floor (including basement) elevated one-foot (1') above the base flood level or together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall develop and/or review structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction are in accordance with accepted standards of practice as outlined in this division. A record of such certification which includes the specific elevation (in relation to mean sea level) to which such structures are flood-proofed shall be maintained by the floodplain administrator.
C. Enclosures: New construction and substantial improvements, with fully enclosed areas below the lowest floor 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 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:
1. A minimum of two (2) openings on separate walls having 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;
2. The bottom of all openings shall be no higher than one-foot (1') above grade; and
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.
D. Manufactured Homes:
1. Require that all manufactured homes to be placed within zone A on a community's FHBM or FIRM shall be installed using methods and practices which minimize flood damage. For the purposes of this requirement, manufactured homes must be elevated and anchored to resist flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.
2. Require that manufactured homes that are placed or substantially improved within zones A1-30, AH, and AE on the community's FIRM on sites outside of a manufactured home park or subdivision; in a new manufactured home park or subdivision; in an expansion to an existing manufactured home park or subdivision; or in an existing manufactured home park or subdivision on which a manufactured home has incurred "substantial damage" as a result of a flood, be elevated on a permanent foundation such bottom of the I-beam of the manufactured home is elevated one-foot (1') above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces. The home shall be installed by a licensed installer according to Oklahoma state law and compliance herewith shall be certified in writing to the floodplain administrator by said installer prior to habitation of the manufactured home.
3. Require that manufactured homes be placed or substantially improved on sites in an existing manufactured home park or subdivision with zones A1-30, AH and AE on the community's FIRM that are not subject to the provisions of this division D. be elevated on a permanent foundation such that the bottom of the I-beam of the manufactured home is elevated one-foot (1') above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
E. Recreational Vehicles: Require that recreational vehicles placed on sites within zones A, A1-30, AH and AE with in the city FIRM, either:
1. Be on the site for fewer than one hundred eighty (180) consecutive days;
2. Be fully licensed and ready for highway use; or
3. Meet the permit requirements of section 11-1-15, and the elevation and anchoring requirements for "manufactured homes" in division D. of this section. 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.
F. Accessory Structures: Accessory structures to be placed on sites within zones A and AE on the city FIRM shall comply with the following:
1. The structure shall be used only for parking and limited storage;
2. The structure shall not be used for human habitation. Prohibited activities or uses include, but are not limited to, working, sleeping, living, cooking, or restroom use;
3. The structure shall be unfinished on the interior;
4. Structures shall be small in size, not exceed six hundred (600) square feet in size;
6. Service facilities such as electrical and heating equipment must be elevated to or above the BFE;
7. The structure shall be constructed and placed on the building site so as to offer the minimum resistance to the flow of floodwaters;
8. The structure shall be considered low in value, designed to have low flood damage potential and constructed with flood resistance materials;
9. The structure shall be firmly anchored to prevent flotation, collapse, and lateral movement;
10. Floodway requirements must be met in the construction of the structure;
11. Openings to relieve hydrostatic pressure during a flood shall be provided below the BFE; and be placed on opposing walls with the net area of not less than one (1) square inch for every square foot of the size of the footprint of the structure (flood vents);
12. The openings (flood vents) shall be located no higher than one foot (1') above grade; and
13. The openings may be equipped with screens, louvers, valves or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(Ord. 268, 7-5-2010; amd. Ord. 339, 9-13-2019)