In all areas of special flood hazard, the following provisions
are required for all new construction and substantial improvements:
A. 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;
B. All new construction or substantial improvements shall be constructed
by methods and practices that minimize flood damage;
C. All new construction or substantial improvements shall be constructed
with materials resistant to flood damage;
D. 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;
E. All new and replacement water supply systems shall be designed to
minimize or eliminate infiltration of floodwaters into the system;
F. 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
G. On-site waste disposal systems shall be located to avoid impairment
to them or contamination from them during flooding.
In all areas of special flood hazard where base flood elevation data has been provided as set forth in §
135-7,
135-14H or
135-19C, the following provisions are required:
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. If a detailed BFE is unavailable within any AO Zone, the lowest floor of the structure (including basement) shall be elevated a minimum of 24 inches above the highest adjacent grade. A registered professional engineer, architect, or land surveyor shall submit a certificate of elevation to the floodplain administrator that the standard of this subsection as proposed in §
135-15A is satisfied.
B. Nonresidential construction. New construction and substantial improvements
of any commercial, industrial or other nonresidential 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 to or above the BFE 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. 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:
(1) A minimum of two openings on separate walls 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.
(2) The bottom of all openings shall be no higher than one foot 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.
(1) Require that all 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.
(2) Require that manufactured homes that are placed or substantially
improved within Zones A1-30, AH, AO and AE on the community's
FIRM on sites (a) outside of a manufactured home park or subdivision,
(b) in a new manufactured home park or subdivision, (c) in an expansion
to an existing manufactured home park or subdivision, or (d) in an
existing manufactured home park or subdivision on which a manufactured
home has incurred "substantial damage," be elevated on a permanent
foundation such that the bottom of the lowest horizontal structural
member of the chassis 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.
(3) Require that manufactured homes that are placed or substantially improved on sites in an existing manufactured home park or subdivision withinin Zones A1-30, AH and AE on the community's FIRM that are not subject to the provisions of Subsection
D of this section be elevated so that either:
(a)
The bottom of the lowest horizontal structural member of the
chassis is at or above the BFE; or
(b)
The manufactured home chassis is supported by reinforced piers
or other foundation elements of at least equivalent strength that
are no less than 36 inches in height above grade and is securely anchored
to an adequately anchored foundation system to resist flotation, collapse,
and lateral movement.
E. Recreational vehicles.
(1) Require that recreational vehicles placed on sites within Zones A1-30,
AH, AO and AE on the community's FIRM either:
(a)
Be on the site for fewer than 180 consecutive days; or
(b)
Be fully licensed and ready for highway use; or
(c)
Meet the permit requirements of §
135-15A, and the elevation and anchoring requirements for manufactured homes in Subsection
D of this section.
(2) 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.