In all areas of special flood hazard, the following provisions
are required for all new construction and substantial improvements:
A.
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;
B.
All new construction or substantial improvements shall be constructed
by methods and practices that minimize flood damage;
C.
All new construction or substantial improvements shall be constructed
with materials resistant to flood damage;
D.
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;
E.
All new and replacement water supply systems shall be designed to
minimize or eliminate infiltration of floodwaters into the system;
F.
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
G.
On-site waste disposal systems shall be located to avoid impairment
to them or contamination from them during flooding.
In all areas of special flood hazard where base flood elevation data has been provided as set forth in § 135-7, 135-14H or 135-19C, the following provisions are required:
A.
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. If a detailed BFE is unavailable within any AO Zone, the lowest floor of the structure (including basement) shall be elevated a minimum of 24 inches above the highest adjacent grade. A registered professional engineer, architect, or land surveyor shall submit a certificate of elevation to the floodplain administrator that the standard of this subsection as proposed in § 135-15A is satisfied.
B.
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 to or above the BFE 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.
C.
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:
(1)
A minimum of two openings on separate walls 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.
(2)
The bottom of all openings shall be no higher than one foot above
grade.
(3)
Openings may be equipped with screens, louvers, valves, or other
coverings or devices, provided that they permit the automatic entry
and exit of floodwaters.
D.
Manufactured homes.
(1)
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.
(2)
Require that manufactured homes that are placed or substantially
improved within Zones A1-30, AH, AO and AE on the community's
FIRM on sites (a) outside of a manufactured home park or subdivision,
(b) in a new manufactured home park or subdivision, (c) in an expansion
to an existing manufactured home park or subdivision, or (d) in an
existing manufactured home park or subdivision on which a manufactured
home has incurred "substantial damage," be elevated on a permanent
foundation such that the bottom of the lowest horizontal structural
member of the chassis 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.
(3)
Require that manufactured homes that are placed or substantially improved on sites in an existing manufactured home park or subdivision withinin Zones A1-30, AH and AE on the community's FIRM that are not subject to the provisions of Subsection D of this section be elevated so that either:
(a)
The bottom of the lowest horizontal structural member of the
chassis is at or above the BFE; or
(b)
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 is securely anchored
to an adequately anchored foundation system to resist flotation, collapse,
and lateral movement.
E.
Recreational vehicles.
(1)
Require that recreational vehicles placed on sites within Zones A1-30,
AH, AO and AE on the community's FIRM either:
(2)
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.
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 BFEs in a Flood Insurance Study (FIS). 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 50 lots or five acres, whichever is lesser, if not otherwise provided pursuant to § 135-7 or 135-14H of this chapter.
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.
A.
Located within the areas of special flood hazard established in § 135-7, are areas designated as shallow flooding. These areas have special flood hazards associated with flood depths of one to three 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.
B.
All new construction and substantial improvement of any residential
structure shall have the lowest floor (including basement) elevated
to at or above the base flood elevation. If a detailed BFE is unavailable,
the lowest floor of the structure (including basement) shall be elevated
a minimum of 24 inches above the highest adjacent grade.
C.
All new construction and substantial improvements of nonresidential
structures:
(1)
Shall have the lowest floor (including basement) elevated to at or
above the base flood elevation or shall be elevated a minimum of 24
inches above the highest adjacent grade.
(2)
Structures of critical facilities are prohibited within the boundaries
of the regulatory floodway as delineated on the community's FIRM.
The definition of "critical facilities" includes but is not limited
to: hospitals, medical clinics, fire stations and police stations
etc.
(3)
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.
(4)
Prohibit encroachment, including fill, new construction, substantial
improvements, and other development within the SFHA 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.
(5)
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 chapter.
D.
If fill material is to be used to elevate any structures in Zone
A, A1-30, AE, AO, AH, AR, or A99, the following will apply:
(1)
Fill material must be compacted to at least 95% of standard laboratory
maximum density (standard proctor) according to ASTM Standard D-698.
(2)
Fill soils must be fine-grained soils of low permeability, such as
those classified as CH, CL, SC, or ML according to ASTM Standard D-2487,
"Classification of Soils for Engineering Purposes." See Table 1804.2
in the 2000 International Building Code (or most recently adopted
code and section) for descriptions of these soils types.
(3)
The fill material must be homogeneous and isotropic; that is, the
soil must be all of one material, and the engineering properties must
be the same in all directions.
E.
A drainage study shall be conducted for all subdivisions or development
greater than 50 lots or covering five or more acres within 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 predevelopment conditions. This shall be accomplished
by the proper design and construction of detention, retention, and/or
drainage systems.
(1)
Attendant utility and sanitary facilities shall be designed so that
the structure below the base specified flood depth in an AO Zone,
or below the base flood elevation in an AH Zone, 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.
F.
A registered professional engineer or architect shall submit a certificate of elevation to the floodplain administrator that the standards of this section, as proposed in § 135-15, are satisfied.
G.
Require within Zone AH or AO adequate drainage paths around structures
on slopes, to guide floodwaters around and away from proposed structures.
A.
A structure shall be deemed to be substantially improved or substantially
damaged when the cumulative costs of improvements or damage repairs,
when combined incrementally over a ten-year period of time, equal
or exceed 50% of the market value of the structure.
B.
All elevation requirements noted in this chapter 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.
C.
Small, detached accessory structures of 400 square feet or less and
valued at $3,000 or less are exempt from the requirements to elevate
or dry-floodproof nonresidential structures. They may be used only
for limited parking of light vehicles and storage of low-cost items.
"Low-cost items" are defined as anything with a value of $250 or less.
