(a)
All elevation requirements noted in this article shall be documented
using the elevation certificate, FEMA 81-31, and shall be certified
by a registered professional engineer, surveyor, or architect, and
shall be submitted to the floodplain administrator.
(b)
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;
(8)
A structure shall be deemed to be substantially improved or substantially
damaged when the costs of the improvements or damage repairs equal
or exceed 40 percent of the market value of the structure.
In all areas of special flood hazards where BFE data has been provided as set forth in section 22.07.007, section 22.07.032(8), or section 22.07.063(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 a minimum of 18 inches above the BFE. 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 22.07.035(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 a minimum of 18 inches or 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 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, and AE 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 the BFE 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 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 the BFE;
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; or (B) be fully licensed and ready for highway use; or (C) meet the permit requirements of section 22.07.035(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.
(c)
BFE 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 22.07.007 or section 22.07.032(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.
Located within the areas of special flood hazard established in section 22.07.007, 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 BFE 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).
(A)
The lowest floor of a residential structure that is outside of the
SFHA shall be elevated (12 inches) above the natural grade or the
crown of the road, whichever is higher.
(B)
When a residential or nonresidential structure is intended to be
constructed in an approximate A zone, a BFE must be determined by
using the same engineering standards and methods that are used to
develop BFE’s in a flood insurance study (FIS).
(2)
All new construction and substantial improvements of nonresidential
structures:
(A)
Have the lowest floor (including basement) elevated to or above the
BFE 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); 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 BFE 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 22.07.035 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.
Located within areas of special flood hazard established in section 22.07.007, 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.
(2)
If subsection (1) above is satisfied, all new construction and substantial improvements 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 community may permit encroachments within the adopted regulatory floodway that would result in an increase in BFE, provided that the community first completes all of the provisions required by 44 CFR chapter 1, section 65.12.
(4)
All development in any form is prohibited within the boundaries of
the regulatory floodway as delineated on the community’s FIRM.
(5)
Structures of any description are prohibited within the boundaries
of the regulatory floodway as delineated on the community’s
FIRM.
(6)
The drilling of water, gas, and/or oil wells is prohibited within
the boundaries of the regulatory floodway as delineated on the community’s
FIRM.
(7)
Fill material of any kind is prohibited within the regulatory floodway
as delineated on the community’s FIRM.
(8)
The storage of hazardous materials, in any form is prohibited within
the boundaries of the regulatory floodway as delineated on the community’s
FIRM.
(9)
A regulatory flood way shall be selected and adopted based on the
principle that the area chosen for the regulatory floodway must be
designed to carry the waters of the base flood, without increasing
the water surface elevation of that flood more than 12 inches at any
point.
(10)
New and substantially improved residential structures and subdivision
designs in the SFHA shall consist of one structure on lots no smaller
than one (1) acre.
(11)
Before development may occur within the floodway fringe area, a hydrologic
and hydraulic study must be accomplished to determine the effects
of such development. Those effects shall not exceed any of the provisions
of this article.
(12)
When fill or any other development are placed in the SFHA that have
the effect of reducing the storage volume of floodwaters in the SFHA,
then an equal amount of storage volume must be created in another
location of the same SFH A to compensate for the storage capacity
lost.
(13)
A drainage study shall be conducted for all subdivisions of any size
or development covering five (5) or more acres within or outside of
the SFHA. Floodwaters originating within these areas shall not be
allowed to drain from the area described in higher quantities or flow
rates than existed under pre-development conditions. This shall be
accomplished by the proper design and construction of detention, retention,
and/or drainage systems.
(Ordinance 11-077 adopted 12/13/11)
