In all areas of special flood hazards, the following standards are required:
A. Anchoring.
(1) All new construction and substantial improvements shall
be anchored to prevent flotation, collapse or lateral movement of the structure.
(2) All manufactured homes shall be installed using methods
and practices which minimize flood damage. Manufactured homes must be elevated
and anchored to resist flotation, collapse or lateral movement. Manufactured
homes shall be elevated to or above the base flood elevation or two feet above
the highest adjacent grade when no base flood elevation has been determined.
Methods of anchoring may include, but are not to be 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. Construction materials and methods.
(1) All new construction and substantial improvements shall
be constructed with materials and utility equipment resistant to flood damage.
(2) All new construction and substantial improvements shall
be constructed using methods and practices that minimize flood damage.
C. Utilities.
(1) Electrical, heating, ventilation, plumbing, air-conditioning
equipment and other service facilities shall be designed and/or located so
as to prevent water from entering or accumulating within the components during
conditions of flooding. When designed for location below the base flood elevation,
a professional engineer's or architect's certification is required.
(2) All new and replacement water supply systems shall be
designed to minimize or eliminate infiltration of floodwaters into the system.
(3) New and replacement sanitary sewage systems shall be
designed to minimize or eliminate the infiltration of floodwaters.
(4) On-site waste disposal systems shall be located to avoid
impairment to them or contamination from them during flooding.
D. Subdivision proposals.
(1) All subdivision proposals shall be consistent with the
need to minimize flood damage.
(2) All subdivision proposals shall have public utilities
and facilities, such as sewer, gas, electrical and water systems, located
and constructed to minimize flood damage.
(3) All subdivision proposals shall have adequate drainage
provided to reduce exposure to flood damage.
(4) Base flood elevation data shall be provided for subdivision
proposals and other proposed developments, including proposals for manufactured
home parks and subdivisions, greater than either 50 lots or five acres.
E. Encroachments.
(1) All proposed development in riverine situations where
no flood elevation data is available (unnumbered A Zones) shall be analyzed
to determine the effects on the floodcarrying capacity of the area of special
flood hazards as set forth in §
60-12A(3). This may require the
submission of additional technical data to assist in the determination.
(2) In all areas of special flood hazard in which base flood
elevation data is available pursuant to §
60-12B or Subsection
D(4)
of this section and no floodway has been determined, the cumulative effects
of any proposed development, when combined with all other existing and anticipated
development, shall not increase the water surface elevation of the base flood
more than one foot at any point.
(3) In all areas of special flood hazard where floodway data
is provided or available pursuant to §
60-12B, the requirements
of §
60-15, Floodways, shall apply.
In all areas of special flood hazards where base flood elevation data
has been provided as set forth in §
60-6, Basis for establishing
areas of special flood hazard, and §
60-12B, Use of other base flood
and floodway data, the following standards are required:
A. Residential construction. New construction and substantial
improvements of any residential structure shall:
(1) Have the lowest floor, including basement or cellar,
elevated to or above the base flood elevation.
(2) Have fully enclosed areas below the lowest floor that
are subject to flooding 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 licensed
professional engineer or architect or meet or exceed the following minimum
criteria:
(a) A minimum of two openings having a total net area of
not less than one square inch for every square foot of enclosed area subject
to flooding;
(b) The bottom of all such openings shall be no higher than
one foot above the lowest adjacent finished grade; and
(c) Openings may be equipped with louvers, valves, screens
or other coverings or devices, provided that they permit the automatic entry
and exit of floodwaters.
B. Nonresidential construction.
(1) New construction and substantial improvements of any
commercial, industrial or other nonresidential structure, together with attendant
utility and sanitary facilities, shall either have the lowest floor, including
basement or cellar, elevated to or above the base flood elevation or be floodproofed
so that the structure is watertight below the base flood level with walls
substantially impermeable to the passage of water. All structural components
located below the base flood level must be capable of resisting hydrostatic
and hydrodynamic loads and the effects of buoyancy.
(a) If the structure is to be elevated, fully enclosed areas
below the base flood elevation shall be designed to automatically (without
human intervention) allow for the entry and exit of floodwaters for the purpose
of equalizing hydrostatic flood forces on exterior walls. Designs for meeting
this requirement must either be certified by a licensed professional engineer
or a licensed architect or meet the following criteria:
[1] A minimum of two openings having a total net area of
not less than one square inch for every square foot of enclosed area subject
to flooding:
[2] The bottom of all such openings shall be no higher than
one foot above the lowest adjacent finished grade: and
[3] Openings may be equipped with louvers, valves, screens
or other coverings or devices, provided that they permit the automatic entry
and exit of floodwaters.
(b) If the structure is to be floodproofed:
[1] A licensed 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 to make the structure watertight with
walls substantially impermeable to the passage of water, with structural components
having the capability of resisting hydrostatic and hydrodynamic loads and
effects of buoyancy; and
[2] A licensed professional engineer or licensed land surveyor
shall certify the specific elevation, in relation to mean sea level, to which
the structure is floodproofed.
(2) The local administrator shall maintain on record a copy
of all such certificates noted in this section.
C. Construction standards for areas of special flood hazards
without base flood elevations. New construction or substantial improvements
of structures, including manufactured homes, shall have the lowest floor,
including basement, elevated to or above the base flood elevation as may be
determined in §
60-12B or two feet above the highest adjacent grade
where no elevation data is available.
(1) New construction or substantial improvements of structures,
including manufactured homes, shall have the lowest floor, including basement,
elevated at least two feet above the highest adjacent grade next to the proposed
foundation of the structure.
(2) Fully enclosed areas below the lowest floor that are
subject to flooding shall be designed to automatically (without human intervention)
allow for the entry and exit of floodwaters for the purpose of equalizing
hydrostatic flood forces on exterior walls. Designs for meeting this requirement
must either be certified by a licensed professional engineer or a licensed
architect or meet the following criteria:
(a) A minimum of two openings having a total net area of
not less than one square inch for every square foot of enclosed area subject
to flooding.
(b) The bottom of all such openings shall be no higher than
one foot above the lowest adjacent finished grade.
(c) Openings may be equipped with louvers, valves, screens
or other coverings or openings, provided that they permit the automatic entry
and exit of floodwaters.
D. Manufactured homes and recreational vehicles.
[Added 2-21-1990 by L.L No. 1-1990]
(1) Any manufactured home placed or substantially improved
in areas of special flood hazard shall be on sites:
(a) Outside of a manufactured home park or subdivision, or
(b) In an existing manufactured home park or subdivision
on which a manufactured home has incurred substantial damage as the result
of a flood, shall 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 shall be securely anchored to an adequately anchored foundation system
to resist flotation, collapse and lateral movement.
(2) Any manufactured home to be placed or substantially improved
on sites in an existing manufactured home park or subdivision in areas of
special flood hazard that is not subject to Subsection
D(1) of this section
shall be elevated so that either:
(a) The lowest floor of the manufactured home is at or above
the base flood elevation; 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 be securely anchored to an
adequately anchored foundation system to resist flotation, collapse and lateral
movement.
(3) Recreational vehicles.
(a) Recreational vehicles placed on sites in areas of special
flood hazard shall either:
[1] Be on the site for fewer than 180 consecutive days;
[2] Be fully licensed and ready for highway use; or
[3] Meet the permit requirements of this chapter and the
elevation and anchoring requirements for manufactured homes in Subsection
D(1) of this subsection.
(b) 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.
Located within areas of special flood hazard are areas designated as
floodways (see definition, §
60-4B). The floodway is an extremely
hazardous area due to high-velocity floodwaters carrying debris and posing
additional threats from potential erosion forces. When floodway data is available
for a particular site as provided by §§
60-6 and
60-12B, all
encroachments, including fill, new construction, substantial improvements
and other development, are prohibited within the limits of the floodway unless
a technical evaluation demonstrates that such encroachments shall not result
in any increase in flood levels during the occurrence of the base flood discharge.