§ 47-14. Specific standards of building construction.

In all areas of special flood hazards where base flood elevation data has been provided as set forth in section 47-3, section 47-10 or section 47-15, the following provisions are required:

(1)

Residential construction. New construction of any residential structure shall have the lowest floor, including basement, elevated to at least two (2) feet above the base flood elevation. A registered professional engineer shall submit a certification to the director of public works that the standard of this subsection is satisfied. Further, once the above requirement has been met, the floor slab elevation of all new residential structures shall be no lower than the top of the street curb of the street on which the structure is located.

(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 two (2) feet 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 director of public works.

(3)

Manufactured homes. Manufactured homes located less than two (2) feet above base flood level:

(a)

Manufactured homes 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)

No manufactured home shall be placed in a floodway.

(c)

The lowest floor of any manufactured home shall be no lower than the base flood elevation.

(d)

All new manufactured homes whose lowest floor is located less than two (2) feet above base flood level but no lower than the base flood elevation shall be anchored to resist flotation, collapse or lateral movement.

Specific requirements are:

(i)

Over-the-top ties at each of the four (4) corners of the manufactured home, with two (2) additional ties per side at intermediate locations and for manufactured homes more than fifty (50) feet long, one additional tie per side;

(ii)

Frame ties at each corner of the home with five (5) additional ties per side at intermediate points and for manufactured homes more than fifty (50) feet long, four (4) additional ties per side;

(iii)

All components of the anchoring system must be capable of carrying a force of forty-eight hundred (4,800) pounds;

(iv)

Any additions to the manufactured home must be similarly anchored.

(e)

Except in an existing manufactured home park, require that all manufactured homes to be placed or substantially improved within Zones A1-30, AH and AE on the community's FIRM be elevated on a permanent foundation such that the lowest floor of the manufactured home is at least two (2) feet above the base flood elevation; and be securely anchored to an adequately anchored foundation system in accordance with the provisions of this section.

(f)

No manufactured home shall be placed in a floodway or floodplain, except in an existing manufactured home park or manufactured home subdivision.

(4)

Floodways. Located within areas of special flood hazard established in section 47-3 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles and erosion potential, the following provisions apply:

(a)

Encroachments are prohibited, including fill, new construction, substantial improvements and other development unless certification by a professional registered engineer is provided demonstrating that encroachments shall not result in any increase in flood levels within the community during the occurrence of the base flood discharge.

(b)

All new construction and substantial improvements permitted by this subsection shall comply with all applicable flood hazard reduction provisions of section 47-14.

(c)

The placement of any mobile home, except in an existing mobile home park or subdivision, is prohibited.

(d)

A person proposing an encroachment within an area designated as a floodway under section 47-3 shall provide to the director of public works sufficient data, certified by a registered professional engineer, to establish that the proposed encroachment, together with a comparable encroachment on the opposite side of the area designated as floodway if such encroachment does not exist but is plausible, is not prohibited by paragraph (a) above and will not increase flooding or divert waters in such a way that any person's life or property will be endangered or subjected to significantly increased flooding.

(5)

Standards for areas of shallow flooding (AO and AH Zones). Within the areas of shallow flooding established by section 47-3, the following provisions apply:

(a)

All new construction and substantial improvements of 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 (at least two (2) feet if no depth number is specified).

(b)

All new construction and substantial improvements of nonresidential 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 (at least two (2) feet if no depth number is specified).

(c)

A registered professional engineer or registered surveyor shall submit a certification to the director of public works that the standards of this section, as proposed in section 47-11(1)(a) are satisfied.

(d)

Require within zones AH or AO adequate drainage paths around structures on slopes, to guide flood waters around and away from proposed structures.

(6)

Enclosed areas below lowest floor. Fully enclosed areas below the lowest floor that 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 must meet or exceed the following minimum criteria: 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. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.

(Ord. No. 3052, § 1, 12-21-77; Ord. No. 3549, § 1, 11-6-80; Ord. No. 5195, §§ 4—7, 4-16-87; Ord. No. 5386, §§ 5—9, 2-4-88)