Current through Vol. 42, No. 1, September 16, 2024
(a)
Applicability of section.
The provisions of this section shall apply to development within any regulatory
floodplain, regardless of whether base flood elevations have been determined or
regulatory floodways have been delineated.
(b)
Temporary fills. Temporary
fills, such as cofferdams or fills used during construction, may be used upon
assumption of full responsibility by the sponsoring agency.
(c)
Roadways, bridges and public
utilities within the regulatory floodplain. For roadways, bridges and
public utilities within the regulatory floodplain, the following shall apply:
(1) When failure or interruption of service
of roadways, bridges, or public utilities would endanger public health or
safety, such roadways, bridges, or public utilities shall be protected to the
base flood elevation or to the elevation of the flood of record, whichever is
greater. In other instances where only economic losses are threatened,
protection shall be provided to the extent practical. A degree of protection
less than the base flood elevation may be justified even in cases where
overtopping could occur.
(2) The
following provisions shall apply to all applicable construction:
(A) Buried crossings such as pipelines shall
be maintained at least three (3) feet below the channel bottom.
(B) Modification, addition and replacement of
existing roadways, bridges and public utilities shall be allowed providing
adequate provision is made for the backwater effects of new flow obstructions
in accordance with
785:55-3-1,
785:55-3-2,
and
785:55-3-3.
(d)
Storage of
materials. Materials that are buoyant, flammable, explosive, or could be
injurious to human, animal or plant life shall be stored above the base flood
elevation, floodproofed or protected by structural measures consistent with the
standards set forth herein. Storage of materials likely to cause water
pollution, in the event of flooding, is prohibited unless adequate safeguards
are provided.
(e)
Emergency
repairs and replacements. Emergency repairs and replacements which will
not threaten public health or safety may be built or constructed without a
permit. If the construction would normally require a permit, application for
such permit must be made as soon as practical. Construction must be removed if
it does not conform to the rules in this Chapter.
(f)
Government projects.
Government projects for flood damage control or other water management purposes
otherwise authorized by law shall be allowed under the following conditions:
(1) The project does not increase flood
damage potential.
(2) Any increase
in flooding above, below or through the project area is mitigated by project
design.
(3) Plans, specifications
and provisions for securing required land rights have been approved and a
development permit issued by the Board; and
(4) A sponsoring agency is authorized and has
accepted full responsibility for operations, maintenance and repair of the
project.
(g)
Dikes, levees, floodwalls and similar structures. For dikes,
levees, floodwalls and similar structures, the following shall apply:
(1) Protection afforded by existing dikes,
levees, floodwalls and similar structures will be evaluated during delineation
of the regulatory floodplain. If the existing levee provides protection to the
base flood elevation, to include at least 3 feet of freeboard, the boundary of
the regulatory floodplain will be located channelward of the levee. Regulatory
floodplains will then be delineated along interior streams, based on their
regulatory flood discharge. If the existing levee does not provide protection
to the base flood elevation, the regulatory floodplain will be delineated as if
the levee does not exist.
(2)
Construction of new levees may be allowed as a government project as provided
in (f) of this section. Protection must be provided equivalent to that provided
by filling to the base flood elevation.
(h)
Reservoir or channel
improvements. The regulatory floodplain shall not be changed on the
basis of proposed reservoir or channel improvements. The regulatory floodplain
may be changed after the reservoir or channel improvements are constructed and
operative. All requests to change the regulatory floodplain boundaries must be
submitted through the Board to FEMA for approval.
(i)
Error in delineation of the
regulatory floodplain. The delineation of the regulatory floodplain
shall not be changed unless it has been shown that the original delineation is
in error or there are changed conditions which modify the original
computations. Any person contesting the correctness of the delineation shall be
given reasonable opportunity to submit his own technical evidence. Such
evidence along with a request to change shall be forwarded to FEMA through the
Board for consideration.
(j)
Methods for providing flood protection. The following are
nonexclusive acceptable methods for providing flood protection:
(1) Permanent fill may be allowed as a means
of providing safe construction sites, provided:
(A) The fill, except in exceptional
circumstances, is contiguous with the boundary of the regulatory floodplain and
shaped, in plan, so as not to create adverse velocities or current
patterns.
(B) The surface of the
fill is above the regulatory flood elevation.
(C) The channelward face of the fill shall be
protected against erosion. If protected by vegetative cover, slopes shall be no
steeper than three (3) horizontal to one (1) vertical. Steeper slopes shall be
protected by riprap. A vertical bulkhead may be used if adequatley founded and
protected against scour.
(D) Fill
shall be of suitable material and so compacted to provide adequate support
under saturated conditions.
(E)
Adequate provision is made for conducting drainage across or through the
fill.
(2) Elevating on
adequately anchored pilings or columns is allowed provided:
(A) The lowest portion of the structural
members of the lowest floor (excluding the pilings and columns) is elevated
one-foot above the base flood elevation and securely anchored to such piles or
columns.
(B) The elevating members
are designed to withstand saturated conditions, hydrostatic pressure, and to
minimize scouring.
(C) The size,
shape, spacing and alignment of elevating members are selected to minimize
turbulence and deflection of current patterns, and to facilitate easy passage
of debris.
(D) Major access and
utility services are elevated at least one (1) foot above the base flood
elevation.
(k)
Channel relocation and
modification. Channel relocation and modification may be allowed
provided the upstream and downstream flood potential is not altered.
(l)
New storm cellars. For new
storm cellars, the following shall apply:
(1)
New storm cellars may be built below the flood elevation provided that such new
storm cellars are:
(A) Limited to nonhabitable
uses,
(B) Designed so that all
electrical, heating and other mechanical equipment is above the regulatory
flood protection level.
(C)
Designed so that hydrostatic pressure and uplift forces are unable to dislodge
structure from the ground and the integrity of the storm cellar is preserved
during the flooding.
(2)
Compliance with requirements of (1) (A) through (C) of this subsection must be
certified by a Registered Professional Engineer or Licensed
Architect.
Amended at 10 Ok Reg
3369, eff 6-25-93; Amended at 14 Ok Reg 2808, eff
7-1-97
