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 anchored to resist
flotation, collapse or lateral movement. 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) All new and replacement water supply systems shall
be designed to minimize or eliminate infiltration of floodwaters into
the system.
(2) New and replacement sanitary sewage systems shall
be designed to minimize or eliminate infiltration of floodwaters into
the systems and discharge from the systems into floodwaters.
(3) On-site waste disposal systems shall be located to
avoid impairment to them or contamination from them during flooding.
(4) Electrical, heating, ventilation, plumbing and 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.
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 development, which contain at least 50
lots or five acres, whichever is less.
E. Enclosure openings. For all new construction and substantial
improvements, 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 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.
In all areas of special flood hazards where base flood elevation data has been provided as set forth in §
141-7, Basis for establishing areas of special flood hazard, or in §
141-14B, Use of other base flood data, the following standards 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 base flood elevation.
B. Nonresidential construction. New construction and
substantial improvement of any commercial, industrial or other nonresidential
structure shall either have the lowest floor, including basement,
elevated to the level of the base flood elevation or, together with
attendant utility and sanitary facilities, shall:
(1) Be floodproofed so that below the base flood level
the structure is watertight with walls substantially impermeable to
the passage of water;
(2) Have structural components capable of resisting hydrostatic
and hydrodynamic loads and effects of buoyancy; and
(3) Be certified by a registered professional engineer
or architect that the design and methods of construction are in accordance
with accepted standards of practice for meeting the applicable provisions
of this subsection. Such certification shall be provided to the official
as set forth in § 141-C(2).
C. Manufactured homes.
(1) Manufactured homes shall be anchored in accordance with §
141-16A(2).
(2) All manufactured homes to be placed or substantially
improved within an area of special flood hazard shall be elevated
on a permanent foundation such that the top of the lowest floor is
at or above the base flood elevation.
Located within areas of special flood hazard established in §
141-7 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 shall be prohibited, including fill,
new construction, substantial improvements and other development unless
a technical evaluation demonstrates that encroachments shall not result
in any increase in flood levels during the occurrence of the base
flood discharge.
B. If Subsection
A is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Article
V.
C. In all areas of special flood hazard in which base
flood elevation data has been provided and no floodway has been designated,
the cumulative effect 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 0.2 of a foot
at any point.