A. General Standards: In all areas of special flood hazards, SFHA, the following provisions are required for all new construction and substantial improvements:
1. All new construction or substantial improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
2. All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage;
3. All new construction or substantial improvements shall be constructed with materials resistant to flood damage;
4. All new construction or substantial improvements 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;
5. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;
6. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and discharge from the systems into floodwaters; and
7. On site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
B. Specific Standards: In all areas of special flood hazards the following provisions are required:
1. Residential Construction: New construction and substantial improvement of any residential structure shall have the lowest floor (including basement) elevated at a minimum of 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 subsection is satisfied. This does not apply for ramps, stairs or other access improvements.
2. Nonresidential Construction: New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor (including basement) elevated at a minimum of one foot (1') above the base flood level or together with attendant utility and sanitary facilities, be designed so that below and one foot (1') above 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 subsection. The Floodplain Administrator shall maintain a record of all flood proofing certifications that includes the specific elevation (in relation to mean sea level) to which each structure has been flood proofed.
3. 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:
a. A minimum of two (2) openings 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;
b. The bottom of all openings shall be no higher than one foot (1') above grade; and
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.
4. Manufactured Homes: Require that all manufactured homes to be placed anywhere within the City of Enid within Zones A and AE on the Garfield County FIRM shall be installed using methods and practices that minimize flood damage and have the bottom of the I-beam elevated one foot (1') above the BFE. For the purposes of this requirement, manufactured homes must be elevated and anchored to resist flotation, collapse, or 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.
5. Recreational Vehicles: Require that recreational vehicles placed on sites within Zones A and AE on the Garfield County FIRM either:
a. Be on the site for fewer than one hundred eighty (180) consecutive days,
b. Be fully licensed and ready for highway use, or
c. Meet the permit requirements of subsection 13-1-5C of this chapter, and the elevation and anchoring requirements for "manufactured homes" in subsection B4 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.
6. Accessory Structure: Accessory structures to be placed on sites within Zones A and AE on the Garfield County FIRM shall comply with the following:
a. The structure shall be unfinished on the interior;
b. The structure shall be used only for parking and limited storage;
c. 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;
d. Service facilities such as electrical and heating equipment must be elevated one foot (1') above the BFE;
e. The structure shall be constructed and placed on the building site so as to offer the minimum resistance to the flow of floodwaters;
f. The structure shall be designed to have low flood damage potential and constructed with flood resistance materials;
g. The structure shall be firmly anchored to prevent flotation, collapse, and lateral movement;
h. Floodway requirements must be met in the construction of the structure;
i. Openings to relieve hydrostatic pressure during a flood shall be provided below the BFE; and
j. The structure shall be located so as not to cause damage to adjacent and nearby structures.
7. Fences: All fences (other than maintenance) within a regulated floodplain will require a development permit, following guidelines set by the Floodplain Administrator.
C. Standards For Subdivisions:
1. The applicant for a development permit for any subdivision located in Zones A and AE which is fifty (50) or more lots or greater than five (5) acres shall generate the base flood elevation data for that subdivision.
2. All subdivisions including the placement of manufactured home parks and subdivisions shall have adequate drainage provided to reduce exposure to flood hazards.
3. All subdivisions including the placement of manufactured home parks and subdivisions shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize or eliminate flood damage.
D. Floodways: The following provisions shall apply to floodways:
1. Encroachments, including, but not limited to, fill, new construction, substantial improvements and other development are prohibited within the adopted floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels within the City of Enid during the occurrence of the base flood discharge.
2. If subsection D1 of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this section.
3. The City of Enid may permit encroachments within the adopted floodway that would result in an increase in base flood elevations, provided that the applicant for the development permit complies with all of 44 CFR section 65.12. (Ord. 2019-05, 4-16-2019, eff. 6-7-2019)