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 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;
(7) On-site
waste disposal systems shall be located to avoid impairment to them
or contamination from them during flooding;
(8) Filling
or the disposal of any materials, which will diminish the water flow
capacity of any waterway or floodplain defined by this chapter, must
be compensated for with remedial action by additional excavation or
otherwise so as not to diminish water capacity; and
(9) Floodplain engineering and procedures requirements within FEMA or the U.S. Corps of Engineers official flood-prone areas shall conform to the engineering criteria as set out in section
7-111.
(1965 Code, app. B, art. V, sec. A)
In all areas of special flood hazards where base flood elevation data have been provided as set forth in section
7-6, section
7-32(7) or section
7-73(c), the following provisions are required:
(1) Residential
construction:
New construction or substantial improvement
of any residential structure shall have the lowest floor, including
basement, elevated to one (1) foot above the base flood elevation.
A registered professional civil engineer, registered architect or
registered public surveyor shall submit a certification to the city
engineer that the standard of this section is satisfied. Floodproofing
will not be allowed as a substitute for the lowest floor, including
basement, being elevated one (1) foot above the base flood elevation.
(2) Nonresidential
construction:
New construction or 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 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 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 (2) openings, having a total net area of not less than one
(1) square inch for every square foot of enclosed area subject to
flooding, shall be provided;
b. The bottoms
of all openings shall be no higher than one (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. In accordance
with the zoning chapter, modular and manufactured housing is not permitted
to be constructed in the city.
b. If, in
the future, construction of manufactured housing should be permitted,
then the following provisions shall apply:
1. Require
that all manufactured homes to be placed within Zone A shall be installed
using methods and practices which minimize flood damage. For the purpose
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. All
manufactured homes shall be in compliance with this section.
3. Require
that all manufactured homes to be placed or substantially improved
within Zones A1-30, AH and AE on the community's FIRM be elevated
on a permanent foundation, such that the lowest floor of the manufactured
home is at or above the base flood elevation, and be securely anchored
to an adequately anchored foundation system, in accordance with the
provision of paragraph (4) of this section.
(1965 Code, app. B, art. V, sec. B)
(a) All subdivision proposals shall be consistent with sections
7-2,
7-3, and
7-4 of this chapter.
(b) All proposals for the development of subdivisions shall meet the development permit requirements of section
7-51, section
7-53, and the provisions of this article. No floodproofing of an existing or proposed building in a new subdivision will be allowed as a substitute for providing the proper finished fill elevation above the base flood or twenty-five-year ultimate development flood elevation, whichever is higher. Buildings in a proposed subdivision shall be on land that is above the controlling flood elevation.
(c) Base flood elevation data shall be provided for subdivision proposals and other proposed development, if not otherwise provided, pursuant to section
7-6 or section
7-32(7) of this chapter and shall conform to section
7-114.
(d) All subdivision
proposals shall have adequate drainage provided to reduce exposure
to flood hazards and in accordance with the city subdivision regulations.
(e) All subdivision
proposals shall have public utilities and facilities such as sewer,
gas, electrical and water systems located and constructed so that
they will not affect the existing water surface elevations of the
base flood or twenty-five-year ultimate development flood whichever
is greater in the area of special flood hazard.
(f) All proposed
subdivisions must be contiguous to high ground that is not subject
to flooding (the base flood or the twenty-five-year ultimate development
flood, whichever is higher), i.e., no "island" will be considered
for platting, unless adequate connecting structures, capable of passing
the base flood or twenty-five-year ultimate development flood whichever
is higher, are provided to high ground (not subject to the controlling
flood of the same floodplain), and an additional one (1) foot of freeboard
is provided to all minimum floor slab elevations.
(g) All proposed subdivisions traversed by an area of special flood hazard, as defined in section
7-6, where the "buildable" portion of the subdivision is severed by the floodplain, shall be provided with adequate access. Adequate access shall be a structure that will pass the control flood (base flood or twenty-five-year ultimate development) without overtopping the structure or affecting the upstream property by backwater, and shall not be designed with excessive velocities.
(h) Proposed
subdivisions that involve the platting of streets shall have at least
one (1) access to an unflooded portion of existing dedicated street
or roadway.
(i) Proposed
subdivisions that involve the platting of streets shall have access
to an existing dedicated street that is above the base flood or twenty-five-year
ultimate development, whichever is greater.
(j) Existing channels shall not be increased or decreased from their natural state, until engineering data as described in section
7-111 have been approved by the city engineer. Floodplain engineering and procedures requirements for subdivisions within FEMA or U.S. Corps of Engineers official flood-prone areas shall conform to the engineering criteria as set out in section
7-111.
(1965 Code, app. B, art. V, sec. C)
There are no specific areas within the city designated as shallow
flooding. These areas have special flood hazards associated with base
flood depths of one (1) to three (3) feet, where a clearly defined
channel does not exist and where the path of flooding is unpredictable
and where velocity flow may be evident. Such flooding is characterized
by ponding or sheet flow; therefore, should any areas ever be so designated,
the following provisions shall apply:
(1) All new
construction and substantial improvements of residential structures
have the lowest floor including basement elevated above the highest
adjacent grade, at least as high as the depth number specified in
feet on the community's FIRM (at least two (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 above the highest adjacent
grade, at least as high as the depth number specified in feet on the
community's FIRM (at least two (2) feet 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 and effects of buoyancy.
(3) A registered professional engineer or architect shall submit a certification to the floodplain administrator that the standards of section
7-53 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.
(1965 Code, app. B, art. V, sec. D)
Located within the areas of special flood hazard established in section
7-6 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 potentials, the following provisions shall apply:
(1) Encroachments
are prohibited, including fill, new construction, substantial improvements
and other development, unless certification by a professional registered
engineer or architect is provided demonstrating that encroachments
shall not result in any increase in flood levels within the community
during the occurrence of the base flood discharge.
(2) If the
preceding paragraph is satisfied, all new construction and substantial
improvements shall comply with all applicable flood hazard reduction
provisions of this article.
(1965 Code, app. B, art. V, sec. E)