In all areas of special flood hazards and moderate 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.
(8)
Compensating floodplain mitigation will be required for any
fill placed below the base flood elevation or 500-year floodplain
elevation, whichever is higher for any new construction or substantial
improvements.
(1999 Code, sec. 3.617; Ordinance 3032 adopted 4/25/2022)
In all areas of special flood hazards and moderate flood hazards where base flood elevation and 500-year floodplain elevation data has been provided as set forth in section 3.04.007, section 3.04.042(8), or section 3.04.073(c), the following provisions are required:
(1)
Residential construction.
New construction of
any residential structure shall have a survey by a surveyor licensed
by the state, requiring all construction and shall be based on free-board
and must include a finished floor elevation of 12 inches above the
centerline of the front street, 18 inches above the top of the curb,
12 inches above the base flood (100-year floodplain) elevation, or
at or above the 500-year floodplain elevation, whichever is highest.
Substantial improvement of any residential structure shall have a
survey by a surveyor licensed by the state, requiring all construction
and shall be based on free-board and must include a finished floor
elevation of 12 inches above the centerline of the front street or
18 inches above the top of the curb, or 12 inches above the base flood
(100-year floodplain) elevation, whichever is higher.
(2)
Nonresidential construction.
New construction
and substantial improvements of any commercial, industrial or other
nonresidential structure shall have a survey by a surveyor licensed
by the state, requiring all construction and shall be based on free-board
and must include a finished floor elevation of 12 inches above the
base floodplain elevation or at or above the 500-year floodplain elevation,
whichever is higher. 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 1 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 1 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 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.
(B)
Require that manufactured homes that are placed or substantially
improved within zones A1-30, AH, AE, and shaded X on the community'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;
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be elevated on a permanent foundation such that the lowest floor
of the manufactured home is elevated to or above the base flood elevation
or to or above the 500-year floodplain, whichever is higher, and be
securely anchored to an adequately anchored foundation system to resist
flotation, collapse, and lateral movement.
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(C)
Require that manufactured homes being placed or substantially
improved on sites in an existing manufactured home park or subdivision
within zones A1-30, AH AE, and shaded X on the community's FIRM that
are not subject to the provisions of this subsection (4) of this section
be elevated so that either:
(i)
The lowest floor of the manufactured home is at or above the
base flood elevation or at or above the 500-year floodplain elevation,
whichever is highter; 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 community'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 3.04.043(a) and the elevation and anchoring requirements for manufactured homes in subsection (4) of this section.
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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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(1999 Code, sec. 3.618; Ordinance 3032 adopted 4/25/2022)
(c)
Base flood elevation and 500-year floodplain 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 3.04.007 or section 3.04.042(8) of this article.
(d)
All subdivision proposals, including the placement of manufactured
home parks and subdivisions, shall have adequate drainage provided
to reduce exposure to flood hazards.
(e)
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.
(1999 Code, sec. 3.619; Ordinance 3032 adopted 4/25/2022)
Located within the areas of special flood hazard established in section 3.04.007 are areas designated as shallow flooding. These areas have special flood hazards associated with flood depths of 1 to 3 feet where a clearly defined channel does not exist, 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
or above the base flood elevation, nearest 500-year floodplain elevation,
or the highest adjacent grade at least as high as the depth number
specified in feet on the community's FIRM (at least 2 feet if no depth
number is specified), whichever is highest.
(2)
All new construction and substantial improvements of nonresidential
structures:
(A)
Have the lowest floor (including basement) elevated to or above
the base flood elevation, nearest 500-year floodplain elevation, or
the highest adjacent grade at least as high as the depth number specified
in feet on the community's FIRM (at least 2 feet if no depth number
is specified), whichever is highest; or
(B)
Together with attendant utility and sanitary facilities be designed
so that below the base specified flood depth in an AO zone, below
the base flood elevation, or nearest 500-year floodplain elevation,
whichever is highest, 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 3.04.043, are satisfied.
(4)
Require within zone AH or AO adequate drainage paths around
structures on slopes, to guide floodwaters around and away from proposed
structures.
(1999 Code, sec. 3.620; Ordinance 3032 adopted 4/25/2022)
Located within areas of special flood hazard established in section 3.04.007 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 community during the occurrence of the
base flood discharge.
(3)
Under the provisions of 44 CFR chapter 1, section 65.12, of the National Flood Insurance Program regulations, a community may permit encroachments within the adopted regulatory floodway that would result in an increase in base flood elevations, provided that the community first completes all of the provisions required by section 65.12.
(1999 Code, sec. 3.621; Ordinance 3032 adopted 4/25/2022)
