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 system into floodwaters.
(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 (as defined above) for any new construction or
substantial improvements.
(1991 Code, sec. 12-66; Ordinance 88-413, art. 5, sec. A, adopted 12/8/87; 2007 Code, sec. 12-285; Ordinance 21-897, sec. 6, adopted 4/8/21; Ordinance adopting 2022 Code)
In all areas of special flood hazards and moderate flood hazards where base flood elevation data has been provided as set forth in section 4.05.007, section 4.05.042(8), or section 4.05.073(c), the following provisions are required:
(1)
Residential construction.
New construction and substantial improvements of any residential structure shall have the lowest floor (including basement) elevated to or above two 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 4.05.043(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 the higher elevation of two feet or more above the one
percent annual chance (100-year) flood level or at or above the base
flood elevation, per the effected [effective] flood insurance study
(FIS); or together with attendant utility and sanitary facilities,
be designed so that below the base flood elevation 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 flood-proofed shall
be maintained by the floodplain administrator.
(3)
Enclosures.
New construction and substantial improvements
with 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 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, 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 shall
be installed using methods and practices which minimize flood damage.
For the purpose 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 or 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, be elevated
on a permanent foundation such that the lowest floor of the manufactured
home is elevated to or above two 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 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 subsection (4) of this section
be elevated so that either:
(i)
The lowest floor of the manufactured home is at or above two feet
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 community’s FIRM either (i) be on the site for fewer than 180 consecutive days, or (ii) be fully licensed and ready for highway use, or (iii) meet the permit requirements of section 4.05.043, 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.
(1991 Code, sec. 12-67; Ordinance 88-413, art. 5, sec. B, adopted 12/8/87; Ordinance 07-637, secs. 8–10,
adopted 5/24/07; Ordinance
18-816, sec. 4, adopted 2/22/18; Ordinance 19-834, sec. 1, adopted 1/10/19; 2007 Code, sec. 12-286; Ordinance 21-897, sec. 7, adopted 4/8/21)
(c)
Base flood elevation data shall be generated for subdivision proposals and other proposed development, including manufactured home parks and subdivisions, which is greater than 50 lots or five acres, whichever is lesser, if not otherwise provided pursuant to section 4.05.007 or section 4.05.042(8).
(d)
All
subdivision proposals, including manufactured home parks and subdivisions,
shall have adequate drainage provided to reduce exposure to flood
hazards.
(e)
All
subdivision proposals, including 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.
(1991 Code, sec. 12-68; Ordinance 88-413, art. 5, sec. C, adopted 12/8/87; 2007 Code, sec. 12-287)
Located within the areas of special flood hazard established in section 4.05.007 are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one to three 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 above the highest
adjacent grade at least as high as the depth number in feet on the
community’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 above the highest
adjacent grade at least as high as the depth number specified in feet
on the community’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 and 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 4.05.073 [4.05.043], 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.
(1991 Code, sec. 12-69; Ordinance 88-413, art. 5, sec. D, adopted 12/8/87; Ordinance 07-637, sec. 11, adopted 5/24/07; 2007 Code, sec. 12-288)
Located within areas of special flood hazard established in section 4.05.007 are areas designed 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
certification by a professional registered engineer or architect is
provided demonstrating that encroachments shall not result in any
increase in flood levels with the community during the occurrence
of the base flood discharge.
(2)
If subsection (1) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this article.
(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.
(1991 Code, sec. 12-70; Ordinance 88-413, art. 5, sec. E, adopted 12/8/87; Ordinance 07-637, sec. 12, adopted 5/24/07; 2007 Code, sec. 12-289)
