A. Residential Construction: New construction and substantial improvement of any residential structure shall have the lowest floor (including basement), elevated to or 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 12-1-050C 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 to or 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 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.
C. Enclosures: For all new construction and substantial improvements, 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 and must meet or exceed the following minimum criteria:
1. A minimum of two (2) openings 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.
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: Manufactured homes shall be anchored in accordance with subsection 12-1-070A of this chapter.
1. All manufactured homes and those to be substantially improved shall conform to the following requirements:
a. 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.
b. 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 lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
c. Manufactured homes placed or substantially improved on sites in existing manufactured home parks or subdivisions that are not subject to the provisions in subsection D1a of this section shall be elevated so that either:
(1) The lowest floor of the manufactured home is at or above the base flood elevation; or
(2) The manufactured home chassis is supported by reinforced piers or other foundation elements that are no less than thirty six inches (36") in height above grade and is securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
E. Recreational Vehicles: Recreational vehicles shall 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 and elevation and anchoring requirements for resisting wind forces.
F. Standards For Subdivisions:
2. All proposals for the development of subdivisions, including the placement of manufactured home parks and subdivisions, shall meet land disturbance permit requirements of this chapter and title 18.
3. Base flood elevation data shall be generated for subdivision proposals and other proposed development including the placement of manufactured home parks and subdivisions greater than fifty (50) lots or five (5) acres, whichever is less, if not otherwise provided pursuant to subsection 12-1-040B, "Basis For Establishing Areas Of Special Flood Hazard", or 12-1-050B8 of this chapter.
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.
G. Areas Of Shallow Flooding (AO/AH Zones): Located within the areas of special flood hazard established in subsection 12-1-040B of this chapter are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one to three feet (1' - 3') where a clearly defined channel does not exist and where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply:
1. Within the AO zone, all new construction and substantial improvements of residential structures have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community's FIRM or at least two feet (2') if no depth number is specified.
2. Within the AO zone, all new construction and substantial improvements of non-residential structures shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community's FIRM or at least two feet (2') if no depth number is specified 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 of effects of buoyancy.
3. A registered professional engineer or architect shall submit a certification to the floodplain administrator that the requirements of this section are satisfied.
4. Within zones AH or AO, adequate drainage paths shall be constructed around structures on slopes, to guide floodwaters around and away from proposed structures. (Ord. 914, 9-22-2009; amd. Ord. 1428, 4- -2020)