(a)
General standards.
For 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.
(b)
Specific standards.
In all areas of special flood hazards where base flood elevation data has been provided as set forth in (i) section 4.03.008, (ii) section 4.03.042(b)(8), or (iii) section 4.03.072(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 or 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 4.03.043(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 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 as 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 wall
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 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 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 within 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
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 4.03.043(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.
(b)
All proposals for the development of subdivisions including the placement of manufactured home parks and subdivisions shall meet floodplain development permit requirements of section 4.03.009; section 4.03.043; and the provisions of division 3 of this article and the requirements of all other local ordinances.
(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 4.03.008 or section 4.03.042(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.
Located within the areas of special flood hazard established in section 4.03.008 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 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).
(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 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 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 4.03.043 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.
Floodways located within areas of special flood hazard established in section 4.03.008, are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwater 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 division 3 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 complete s all of the provisions required by section 65.12.
(Ordinance 2003-O-05 adopted 8/19/03; Ordinance 2008-O-96 adopted 8/19/08; Ordinance adopting
Code; Ordinance 2020-O-01 (202)
adopted 1/21/20)
