In all areas of special flood hazards the following provisions
are required for all new construction and substantial improvements:
(1) 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;
(2) All new
construction or substantial improvements shall be constructed by methods
and practices that minimize flood damage;
(3) All new
construction or substantial improvements shall be constructed with
materials resistant to flood damage;
(4) 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;
(5) All new
and replacement water supply systems shall be designed to minimize
or eliminate infiltration of floodwaters into the system;
(6) 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
(7) On-site
waste disposal systems shall be located to avoid impairment to them
or contamination from them during flooding.
(Ordinance O2019-11-13 adopted 11/19/19)
In all areas of special flood hazards where base flood elevation
data has been provided as set forth in section 3.607, section 3.632(8),
or section 3.643(c), the following provisions are required:
(1) Residential
Construction.
New construction and substantial improvement
of any residential structure shall have the lowest floor (including
basement), elevated to two (2) 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 as proposed in section 3.633(a)(1), is satisfied.
(2) 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 two
(2) feet 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 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.
(3) 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:
(A) 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.
(B) The
bottom of all openings shall be no higher than one foot above grade.
(C) Openings
may be equipped with screens, louvers, valves, or other coverings
or devices provided that they permit the automatic entry and exit
of floodwaters.
(4) Manufactured
Homes.
(A) Require
that all manufactured homes to be placed within zone A on a city’s
flood hazard boundary map (FHBM) or flood insurance rate map (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.
(B) Require
that manufactured homes that are placed or substantially improved
within zones A1-30, AH, and AE on the city’s FIRM on sites (i)
outside of a manufactured home park or subdivision, (ii) in a new
manufactured home park or subdivision, (iii) in an expansion to an
existing manufactured home park or subdivision, or (iv) in an existing
manufactured home park or subdivision on which a manufactured home
has incurred “substantial damage” as a result of a flood,
be elevated on a permanent foundation such that the lowest floor of
the manufactured home is elevated to two (2) feet above the base flood
elevation and be securely anchored to an adequately anchored foundation
system to resist flotation, collapse, and lateral movement.
(C) Require
that manufactured homes be placed or substantially improved on sites
in an existing manufactured home park or subdivision with zones A1-30,
AH and AE on the city’s FIRM that are not subject to the provisions
of subsection (4) of this section be elevated so that either:
(i) The lowest floor of the manufactured home is elevated to two (2)
feet or above the base flood elevation; or
(ii) 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.
(5) Recreational
Vehicles.
Require that recreational vehicles placed on
sites within zones A1-30, AH, and AE on the city’s FIRM either:
(A) Be
on the site for fewer than 180 consecutive days;
(B) Be
fully licensed and ready for highway use; or
(C) Meet
the permit requirements of section 3.633(a), and the elevation and
anchoring requirements for “manufactured homes” in subsection
(4) of this section.
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.
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(Ordinance O2019-11-13 adopted 11/19/19)
(a) All subdivision
proposals including the placement of manufactured home parks and subdivisions
shall be consistent with sections 3.602, 3.603, 3.604 of this article.
(b) All proposals
for the development of subdivisions including the placement of manufactured
home parks and subdivisions shall meet development permit requirements
of section 3.608; section 3.633; and the provisions of this division.
(c) Base flood
elevation data shall be generated for subdivision proposals and other
proposed development including the placement of manufactured home
parks and subdivisions which is greater than 50 lots or 5 acres, whichever
is lesser, if not otherwise provided pursuant to section 3.607 or
section 3.632(8) of this article.
(d) Base flood
elevation data, with the establishment of a floodway, shall be generated
by a detailed engineering study for all zone A areas, within one hundred
(100) feet of the boundary lines of zone A areas, and other streams
not mapped by FEMA, as indicated on the city’s FIRM.
(e) All subdivision
proposals including the placement of manufactured home parks and subdivisions
shall have adequate drainage provided to reduce exposure to flood
hazards.
(f) 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.
(Ordinance O2019-11-13 adopted 11/19/19)
Located within the areas of special flood hazard established
in section 3.607, are areas designated as shallow flooding. These
areas have special flood hazards associated with base flood depths
of 1 to 3 feet where a clearly defined channel does not exist and
where the path of flooding is unpredictable and where velocity flow
may be evident. Such flooding is characterized by ponding or sheet
flow; therefore, the following provisions apply:
(1) All new
construction and substantial improvements of residential structures
have the lowest floor (including basement) elevated to two (2) feet
above the base flood elevation or above the highest adjacent grade
at least as high as the depth number specified in feet on the city’s
FIRM (at least two feet if no depth number is specified).
(2) All new
construction and substantial improvements of nonresidential structures:
(A) Have
the lowest floor (including basement) elevated to two (2) feet above
base flood elevation or above the highest adjacent grade at least
as high as the depth number specified in feet on the city’s
FIRM (at least two feet if no depth number is specified); or
(B) Together
with attendant utility and sanitary facilities be designed so that
below the base specified flood depth in an AO zone, or below the base
flood elevation in an AH zone, level the structure is watertight with
walls substantially impermeable to the passage of water and with structural
components having the capability of resisting hydrostatic and hydrodynamic
loads of effects of buoyancy.
(3) A registered
professional engineer or architect shall submit a certification to
the floodplain administrator that the standards of this section, as
proposed in section 3.633(a)(1), are satisfied.
(4) Require
within zones AH or AO adequate drainage paths around structures on
slopes, to guide floodwaters around and away from proposed structures.
(Ordinance O2019-11-13 adopted 11/19/19)
Floodways located within areas of special flood hazard established
in section 3.607, 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) Encroachments
are prohibited, including fill, new construction, substantial improvements
and other development within the adopted regulatory floodway unless
it has been demonstrated through hydrologic and hydraulic analyses
performed in accordance with standard engineering practice that the
proposed encroachment would not result in any increase in flood levels
within the city during the occurrence of the base flood discharge.
(2) If subsection
(1) above is satisfied, all new construction and substantial improvement shall comply with all applicable flood hazard reduction provisions of this division.
(3) Under the provisions of 44 CFR chapter
1, section 65.12, of the National Flood Insurance Program regulations, a city may permit encroachments within the adopted regulatory floodway that would result in an increase in base flood elevations, provided that the city first completed all of the provisions required by section 65.12.
(Ordinance O2019-11-13 adopted 11/19/19)