In all areas of special flood hazard, the following standards
are required:
(1)
Anchoring.
a.
All
new construction or substantial improvements shall be anchored to
prevent flotation, collapse, or lateral movement of the structure.
b.
All
manufactured homes must likewise be anchored to prevent flotation,
collapse, or lateral movement, and shall be installed using methods
and practices that minimize flood damage. Anchoring methods may include,
but are not limited to, use of over-the-top or frame ties to ground
anchors. (Reference FEMA's "Manufactured Home Installation in Flood
Hazard Areas" guidebook for additional techniques.)
(2)
AH
Zone drainage.
Adequate drainage paths are required around
structures on slopes to guide floodwaters around and away from proposed
structures.
(3)
Construction
materials and methods.
a.
All
new construction and substantial improvements shall be constructed
with materials and utility equipment resistant to flood damage.
b.
All
new construction and substantial improvements shall be constructed
using methods and practices that minimize flood damage.
c.
Electrical,
heating, ventilation, plumbing, and air-conditioning equipment and
other service facilities shall be designed and/or otherwise elevated
or located so as to prevent water from entering or accumulating within
the components during conditions of flooding.
(4)
Utilities.
a.
All
new and replacement water supply systems shall be designed to minimize
or eliminate infiltration of floodwaters into the system;
b.
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; and
c.
On-site
waste disposal systems shall be located to avoid impairment to them
or contamination from them during flooding.
(5)
Standards
for subdivisions.
a.
All
subdivision proposals, including the placement of manufactured home
parks and subdivisions, shall be consistent with the need to minimize
flood damage;
b.
All
proposals for the development of subdivisions, including the placement
of manufactured home parks and subdivisions, shall meet floodplain
development permit requirements of this article;
c.
All
subdivision proposals, including the placement of manufactured home
parks and subdivisions, shall have public utilities and facilities
such as sewer, gas, electrical, and water systems located and constructed
to minimize or eliminate flood damage;
d.
All
subdivision proposals, including the placement of manufactured home
parks and subdivisions, shall have adequate drainage provided to reduce
exposure to flood damage; and
e.
Where
base flood elevation data has not been provided or is not available
from another authoritative source, it shall be generated for subdivision
proposals and other proposed developments which contain at least 50
lots or five acres (whichever is less).
(6)
Review
of building permits.
Where elevation data is not available
either through the flood insurance study, flood insurance rate map
(FIRM), or from another authoritative source, applications for building
permits shall be reviewed to ensure that proposed construction will
be reasonably safe from flooding. The test of reasonableness is a
local judgment and includes use of historical data, high water marks,
photographs of past flooding, etc., where available. Failure to elevate
at least two feet above grade in these zones may result in higher
insurance rates.
(Ordinance 07-525-10, § 1(art.
III, § A), adopted 6/7/2007)
(a)
Residential
construction.
(1)
New construction and substantial improvement of any residential structure
shall have the lowest floor, including basement, elevated to 1½
feet above the base flood elevation. A registered professional engineer,
architect, or land surveyor shall submit a certification to the floodplain
administrator that the standard of this subsection, is satisfied.
(2)
Fully enclosed areas below the lowest floor that are subject to flooding
are prohibited, or 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.
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.
b.
The bottom of all openings shall be no higher than one foot above
grade.
c.
Openings may be equipped with screens, louvers, or other coverings
or devices provided that they permit the automatic entry and exit
of floodwaters.
d.
Below grade, crawlspaces are prohibited at sites where the velocity
of floodwaters exceeds five feet per second.
e.
All building utility systems within the crawlspace shall be elevated
above base flood elevation or be designed so that floodwaters cannot
The interior of a crawlspace below the base flood elevation must not
be more than two feet below the lowest adjacent exterior grade (LAG)
and the height of the below-grade crawlspace, measured from the interior
grade of the crawlspace to the top of the crawlspace foundation must
not exceed four feet at any point.
f.
Below-grade, crawlspaces constructed in accordance with the requirements
listed in this subsection shall not be considered basements. However,
applicants who construct buildings that have below-grade crawlspaces
are hereby advised that such buildings will have higher flood insurance
premiums than buildings that have crawlspaces with interior elevations
at or above the lowest adjacent grade.
(b)
Nonresidential
construction.
(1)
New construction and substantial improvements of any commercial,
industrial, or other nonresidential structure shall either have the
lowest floor, including basement, elevated to 1½ feet above
the base flood level, or, together with attendant utility and sanitary
facilities, shall:
a.
Be floodproofed so that below the base flood level the structure
is watertight with walls substantially impermeable to the passage
of water;
b.
Have structural components capable of resisting hydrostatic and hydrodynamic
loads and effects of buoyancy;
c.
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 provisions of this subsection based
on their development and/or review of the structural design, specifications
and plans. Such certifications shall be provided to the official;
(2)
Nonresidential structures that are elevated, not floodproofed, must
meet the same standards for space below the lowest floor;
(3)
Applicants floodproofing nonresidential buildings shall be notified
that flood insurance premiums will be based on rates that are one
foot below the floodproofed level (e.g., a building floodproofed to
the base flood level will be rated as one foot below).
(c)
Manufactured
homes.
(1)
All manufactured homes to be placed or substantially improved 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" as the result of a flood;
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shall be elevated on a permanent foundation such that the lowest
floor of the manufactured home is elevated at or above the base flood
elevation and be securely anchored to an adequately designed foundation
system to resist flotation, collapse and lateral movement.
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(2)
Manufactured homes to be placed or substantially improved on sites
in an existing manufactured home park or subdivision within Zones
A1-30, AH, and AE on the community's flood insurance rate map (FIRM)
that are not subject to the above manufactured home provisions shall
be elevated so that either:
a.
The lowest floor of the manufactured home is elevated 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 are securely anchored
to an adequately designed foundation system to resist flotation, collapse,
and lateral movement.
(d)
Recreational
vehicles.
Recreational vehicles placed on sites are required
to either:
(1)
Be on the site for fewer than 180 consecutive days;
(2)
Be fully licensed and ready for highway use, on its wheels or jacking
system, attached to the site only by quick disconnect type utilities
and security devices, and have no permanently attached additions;
or
(3)
Meet the requirements of this section and the elevation and anchoring
requirements for manufactured homes.
(Ordinance 07-525-10, § 1(art.
III, § B), adopted 6/7/2007)
In areas where a regulatory floodway has not been designated,
no new construction, substantial improvements, or other development
(including fill) shall be permitted within Zones A1-30 and AE on the
community's flood insurance rate map (FIRM), unless it is demonstrated
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.
(Ordinance 07-525-10, § 1(art.
III, § C), adopted 6/7/2007)
Located within areas of special flood hazard 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 shall apply:
(1)
Prohibit
encroachments, including fill, new construction, substantial improvements,
and other development unless certification by a registered professional
civil engineer is provided demonstrating through hydrologic and hydraulic
analyses performed in accordance with standard engineering practice
that encroachments shall not result in any increase in flood levels
during the occurrence of the base flood discharge.
(Ordinance 07-525-10, § 1(art.
III, § D), adopted 6/7/2007)
Shallow flooding areas appear on flood insurance rate maps (FIRMs)
as AO Zones with depth designations. The base flood depths in these
zones range from one foot to three feet above ground where a clearly
defined channel does not exist, or where the path of flooding is unpredictable
and where velocity flow may be evident. Such flooding is usually characterized
as sheet flow. In these areas, the following provisions apply:
(1)
New
construction and substantial improvements of residential structures
and manufactured homes within AO Zones shall have the lowest floor
(including basement) elevated above the highest grade adjacent to
the building, one foot or more above the depth number specified on
the flood insurance rate map (FIRM) (at least two feet if no depth
number is specified).
(2)
New
construction and substantial improvements of nonresidential structures
within AO Zones shall either:
a.
Have
the lowest floor (including basement) elevated above the highest adjacent
grade of the building site, one foot or more above the depth number
specified on the flood insurance rate map (FIRM) (at least two feet,
if no depth number is specified).
b.
Together
with attendant utility and sanitary facilities, be completely floodproofed
to or above that level so that any space below that level 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. If this method is
used, compliance shall be certified by a registered professional engineer
or architect.
c.
Require
adequate drainage paths around structures on slopes to guide floodwaters
around and away from proposed structures
(3)
Recreational
vehicles placed on sites within AO Zones on the community's flood
insurance rate map (FIRM) shall either:
a.
Be
on the site for fewer than 180 consecutive days;
b.
Be
fully licensed and ready for highway use, 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; or
c.
Meet
the requirements of the section above and the elevation and anchoring
requirements for manufactured homes.
(4)
Critical
facility. Construction of new critical facilities shall be, to the
extent possible, located outside the limits of the special flood hazard
area (SFHA) (100-year floodplain). Construction of new critical facilities
shall be permissible within the special flood hazard area (SFHA) if
no feasible alternative site is available. Critical facilities constructed
within the special flood hazard area (SFHA) shall have the lowest
floor elevated three feet or to the height of the 500-year flood,
whichever is higher. Access to and from the critical facility should
also be protected to the height utilized above. Floodproofing and
sealing measures must be taken to ensure that toxic substances will
not be displaced by or released into floodwaters. Access routes elevated
to or above the level of the base flood elevation shall be provided
to all critical facilities to the extent possible.
(Ordinance 07-525-10, § 1(art.
III, § E), adopted 6/7/2007)
