§ 11-23. Specific standards.

In all areas of special flood hazard designated on the community's FIRM, where base flood elevation data have been provided, as set forth in article III, section 11-9, the following provisions, in addition to the standards of article V, section 11-22, are required:

(1)

Residential construction. New construction and substantial improvement of any residential building (including manufactured home) shall have the lowest floor, including basement, elevated to no lower than two (2) feet above the base flood elevation. Should solid foundation perimeter walls be used to elevate a structure, flood openings sufficient to automatically equalize hydrostatic flood forces on exterior walls of enclosures that are subject to flooding, shall be provided in accordance with standards of article V, section 11-23(4).

(2)

Non-residential construction. New construction and substantial improvement of any commercial, industrial, or non-residential building (including manufactured home) shall have the lowest floor, including basement, elevated to no lower than two (2) feet above the base flood elevation. Buildings located in all A-Z zones may, together with attendant utility and sanitary facilities, be flood proofed in lieu of being elevated providing that all areas of the building below the base flood elevation (plus a minimum of two (2) feet of freeboard are water tight with walls substantially impermeable to the passage of water, and use structural components having the capability of resisting hydrostatic and hydro-dynamic loads and the effect of buoyancy. A registered professional engineer or architect shall certify that the standards of this subsection are satisfied. Such certification, together with an operation and maintenance plan, shall be provided to the floodplain administrator.

(3)

In special flood hazard areas with base flood elevations (Zones AE and A1-30) but without floodways, no encroachments, including fill material or structures, shall be permitted unless certification by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the community. The engineering certification must be supported by technical data that conforms to standard hydraulic engineering principles.

(4)

Enclosures. New construction and substantial improvements that include fully enclosed areas formed by foundation and other exterior walls below the lowest floor shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls. Enclosed areas, including crawl spaces, shall be used solely for parking of vehicles, building access, and storage.

a.

Designs for complying with this requirement must either be certified by a professional engineer or architect or meet or exceed the following criteria:

Provide a minimum of two (2) openings, on different sides of each enclosed area; if a structure has more than one (1) enclosed area below the base flood elevation, each shall have openings on exterior walls;

The total net area of all openings shall be at least one (1) square inch for each square foot of enclosed area, or the openings shall be designed and the construction documents shall include a statement that the design and installation will provide for equalization of hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwaters;

The bottom of all openings shall be no higher than one (1) foot above interior grade (which must be equal to in elevation or higher than the exterior grade);

Openings shall allow the passage of an object at least three (3) inches in diameter.

Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions; and

Limited in use to storage, parking of vehicles, and building access.

b.

Access to the enclosed area shall be minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standard exterior door) or entry to the living area (stairway or elevator); and

c.

The interior portion of such enclosed area shall not be finished or partitioned into separate rooms.

(5)

Detached storage buildings, sheds, or other like accessory improvements, excluding detached garages, carports, and boat houses, shall solely be used for parking of vehicles and storage. Such storage space shall not be used for human habitation and shall be limited to storage of items that can withstand exposure to the elements and have low flood damage potential. The storage space shall be constructed of flood resistant or breakaway materials, and equipment and service utilities, such as electrical outlets, shall be limited to essential lighting and other incidental uses, and must be elevated or floodproofed. Flood openings in accordance with the standards of article V, section 11-23(4) shall also be required. These accessory structures shall be constructed and placed on the building site so as to offer the minimum resistance to the flow of floodwaters.

(6)

Accessory improvements and other appurtenant structures shall be firmly anchored to prevent flotation that may result in damage to other structures.

(7)

Standards for manufactured homes and recreational vehicles.

a.

All manufactured homes placed, or substantially improved, on individual lots or parcels, in existing manufactured home parks or subdivisions, in expansions to existing manufactured home parks or subdivisions, in new manufactured home parks or subdivisions or in substantially improved manufactured home parks or subdivisions, must meet all the requirements for new construction, including elevation and anchoring and the flood openings requirements of article v, section 11-23(4).

Manufactured homes must be:

(i)

Elevated on a permanent foundation to have its lowest floor elevated to no lower than two (2) feet above the base flood elevation; and

(ii)

Securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

b.

All manufactured homes placed or substantially improved, excepting manufactured homes that have incurred substantial damage as a result of a flood, in an existing manufactured home park or subdivision must be elevated so that:

(i)

The lowest floor of the manufactured home is elevated to no lower than two (2) feet above the base flood elevation and be securely anchored to an adequately anchored foundation support system to resist flotation, collapse; and lateral movement; or

(ii)

The manufactured home chassis is supported by reinforced piers or other foundation elements of at least an equivalent strength, of no less than thirty-six (36) inches in height above the highest adjacent grade and adequately anchored foundation support system to resist floatation, collapse, and lateral movement.

c.

All recreational vehicles placed on sites must either:

(i)

Be on site for fewer than 180 consecutive days;

(ii)

Be fully licensed and ready for highway use; or

(iii)

Must meet all requirements for new construction, including anchoring and elevation requirement of article V, section 11-23(8)(a) or article V, section 11-23(8)(b)(i) above.

A recreational vehicle is ready for highway use if it is licensed and insured in accordance with the State of Mississippi motor vehicle regulations, 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.

(8)

Floodways. Located within areas of special flood hazard adopted by reference in article III, section 11-9 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles and has erosion potential, the following provisions shall apply:

a.

Prohibit encroachments, including fill, new construction, substantial improvements, and other developments unless certification (with supporting technical data) by a registered professional engineer is provided demonstrating that encroachments shall not result in any increase in flood levels within the community during occurrence of the base flood discharge;

b.

If article V, section 11-23(8)a. above is satisfied, all new construction and substantial improvements shall comply with all applicable flood damage prevention standards of article V.

c.

Prohibit the placement of manufactured homes (mobile homes), except in an existing manufactured homes (mobile homes) park or subdivision. A replacement manufactured home may be placed on a lot in an existing manufactured home park or subdivision provided the anchoring standards of article v, section 11-22(2), and the standards of article V, section 11-23(1) through (3) and the encroachment standards of this article V, section 11-23(8)a., are met.

(Ord. of 2-2-10(1), § 2; Ord. of 1-31-17(1) ; Ord. of 7-18-2017(2) )

Cross reference

Subdivision regulations, App. A.