Specific standards for Floodplains in Canadian County

Residential Construction

New construction and substantial improvement of any residential structure shall have the lowest floor (including basement), elevated two (2) feet 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 as proposed in Article 4, Section C (1) a., is satisfied.

Non-residential Construction

New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor (including basement) elevated two (2) feet above the base flood elevation or together with attendant utility and sanitary facilities, be designed so that below the base flood elevation 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. A record of such certification which includes the specific elevation (in relation to mean sea level) to which such structures are floodproofed shall be maintained by the Floodplain Administrator.

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 openings on opposing outside walls below the base flood elevation 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 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.

Manufactured Homes

a) Require that all manufactured homes to be placed within Zone A on a community's FIRM shall be installed using methods and practices that minimize flood damage. For the purposes of this requirement, the bottom of the lowest I-beam of the manufactured homes must be elevated at least two feet above the base flood elevation 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.

b) Require that manufactured homes that are placed or substantially improved within Zones A1-30, AH, and AE on the community's FIRM on sites (i) outside of a manufactured home park or subdivision, (ii) in a new manufactured home park or subdivision, (iii) in an expansion to an existing manufactured home park or subdivision, or (iv) 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 that the bottom of the lowest I-beam of the manufactured home is elevated two (2) feet above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

c) 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 paragraph (4) of this section be elevated so that the bottom of the lowest I-beam of the manufactured home is elevated two (2) feet above the base flood elevation, and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement support the manufactured home chassis.

Recreational Vehicles

Require that recreational vehicles placed on sites within Zones A, A1-30, AH, and AE on the community's FIRM either: 

a) Be on the site for fewer than 180 consecutive days, 

b) Be fully licensed and ready for highway use, or

c) Meet the permit requirements of Article 4, Section C (1), and the elevation and anchoring requirements for "manufactured homes" in paragraph (4) 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.

Accessory Structure

a) Structure is low valued and represents a minimal investment.

b) Structure shall be small and not exceed 600 square feet in size.

c) Structure shall be unfinished on the interior.

d) Structure can be used only for parking and limited storage.

e) Structure shall not be used for human habitation (including work, sleeping, living, cooking, or restroom areas).

f) Service facilities such as electrical and heating equipment must be elevated to or above the BFE or floodproofed.

g) Structure is constructed and placed on building site so as to offer the minimum resistance to the flow of floodwaters.

h) Structure is designed to have low flood damage potential i.e. constructed with flood resistance materials.

i) Structure is firmly anchored to prevent flotation, collapse, and lateral movement.

j) Floodway requirements must be met in the construction of the structure.

k) Openings to relieve hydrostatic pressure during a flood shall be provided below the BFE.

l) Structure is to be located so as not to cause damage to adjacent and nearby structures.

Subdivisions

1. All subdivision proposals including the placement of manufactured home parks and subdivisions shall be consistent with Article 1, Sections B, C, and D of these regulations.

2. All proposals for the development of subdivisions including the placement of manufactured home parks and subdivisions shall meet Development Permit requirements of Article 3, Section C; Article 4, Section C; and the provisions of Article 5 of these regulations.

3. Base flood elevation data shall be generated for subdivision proposals and other proposed development including the placement of manufactured home parks and subdivisions which is greater than 50 lots or 5 acres, whichever is lesser, if not otherwise provided pursuant to Article 3, Section B or Article 4, Section B (8) of these regulations.

4. All subdivision proposals including the placement of manufactured home parks and subdivisions shall have adequate drainage provided to reduce exposure to flood hazards.

5. All subdivision proposals 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.

6. All proposals for the development of subdivisions including the placement of manufactured home parks and subdivisions shall have the roads that ingress and egress to and from the subdivision and each lot therein at or above the base flood elevation, so that during times of flood, residents will have safe access in and out of the subdivision.

7. Each lot in all proposals for the development of subdivisions including the placement of manufactured home parks and subdivisions shall have a building site at or above the base flood elevation.

8. All final plats for the development of subdivisions including the placement of manufactured home parks and subdivisions must show the current effective floodplain boundaries and show a base flood elevation in each lot that lies in the floodplain.