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 a base flood.
(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.
(7)
On-site
waste disposal systems shall be located to avoid impairment to them
or contamination from them during flooding.
(8)
All
new construction and improvements to existing construction of storm
sewers, culverts, channels, creeks and drainage courses shall be designed
to convey the fully developed base flood of the area contributing
to the facility with at least one foot of freeboard.
(9)
All
new developments shall utilize regional detention and/or retention
facilities as directed by the floodplain administrator to help collect
silt from stormwater runoff, to minimize increases in flood elevations
from development and increased runoff.
(10)
Preserve the existing conveyance capacity of floodplains and allow
no rise as a result of a floodplain development project. A rise of
less than six (6) inches may be allowed if it is demonstrated to only
impact the subject development tract and that the principle of equal
conveyance reduction has been applied.
(11)
Floodplains may be reclaimed provided it is 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 and FEMA has approved a conditional letter
of map revision (CLOMR). In addition, development shall not reduce
total valley storage for all special flood hazard areas on the city’s
FIRMs. The only exception that will be considered is an increase confined
to being within the limits of the property that is proposed for reclamation,
and such rise will be limited to a maximum of six (6) inches within
the subject tract.
(Ordinance 2009-27 adopted 11/9/09)
In all areas of special flood hazards where base flood elevation data has been provided as set forth in section 3.05.007, section 3.05.071(b), or section 3.05.043, 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 at least two (2) feet above the base flood elevation. A registered professional engineer, architect or land surveyor shall submit an elevation certificate to the floodplain administrator that the standard of this subsection (1), as proposed in section 3.05.072, 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 at least two (2) feet above the base flood elevation 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 to a level at least two (2) feet above
the base flood elevation. 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 the certification which
includes the specific elevation, in relation to mean sea level, to
which the structures are floodproofed shall be provided to 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 constructed to an elevation at or below
the base flood elevation 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 are provided with a total net area of not
less than one square inch for every square foot of enclosed area constructed
at or below the base flood elevation.
(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 and will not become clogged.
(4)
Manufactured homes.
(A)
Require that all manufactured homes to be placed within zone A on
the city’s FHBM or FIRM shall be installed using methods and
practices that 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, AR 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 in 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 at least 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.
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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 and AE on the city’s FIRM that are not subject
to the provisions of this subsection (4) be elevated so that either:
(i)
The lowest floor of the manufactured home is at least two (2) feet
above the base flood elevation.
(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 and that the lowest floor be at least two (2)
feet above the base flood elevation.
(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 3.05.072 and the elevation and anchoring requirements for manufactured homes in subsection (4) above. 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.
(Ordinance 2009-27 adopted 11/9/09)
(c)
Base flood elevation data and fully developed base flood elevation data shall be generated for subdivision proposals and other proposed development, including the placement of manufactured home parks and subdivisions, which are greater than 8 lots or two acres, whichever is lesser, if not otherwise provided pursuant to section 3.05.007.
(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 damage from the base flood.
(Ordinance 2009-27 adopted 11/9/09)
(a)
(1)
Located within the areas of special flood hazard established in section 3.05.007 are areas designated as shallow flooding.
(2)
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.
(b)
The
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 two
(2) feet above the depth number specified in feet on the city’s
FIRM (or at least two feet above highest adjacent grade if no depth
number is specified).
(2)
All new construction and substantial improvements of nonresidential
structures:
(A)
Have the lowest floor, including basement, elevated two (2) feet
above the depth number specified in feet on the city’s FIRM
(or at least two (2) feet above the highest adjacent grade if no depth
number is specified); or
(B)
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 or 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 division 3 of this article, 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.
(Ordinance 2009-27 adopted 11/9/09)
(a)
Located within areas of special flood hazard established in section 3.05.007, or as a result of a detailed study, are areas designated as floodways.
(b)
Since
the floodway is an extremely hazardous area due to the velocity of
floodwaters that can carry debris or projectiles, and these areas
can be subject to erosion, 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
and FEMA has approved a conditional letter of map revision (CLOMR).
(2)
If subsection (b)(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 65.12 of the National Flood Insurance
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 applies for a conditional
FIRM and floodway revision through FEMA.
(Ordinance 2009-27 adopted 11/9/09)
