In all areas of special flood hazards the following standards
are required:
(1) No rise of BFE in the floodplain.
No new construction,
substantial improvements, or other development (including cut and/or
fill) shall be permitted within zones A and A1-A30 on the community’s
flood insurance rate maps unless it is first demonstrated by engineering
data submitted by the applicant’s engineer in accordance with
the various requirements and procedures set forth in this article
that the cumulative effect of the proposed development will not increase
the water surface elevation of the base flood at any point within
the community, or immediately adjacent to its territory.
(2) Compensatory storage.
Whenever any portion of a floodplain
is authorized for use, the space occupied by the authorized fill or
structure below the base flood elevation shall be compensated for
and balanced by a hydraulically equivalent volume of excavation taken
from below the base flood elevation. All such excavations shall be
constructed to drain freely to the watercourse.
(3) Water velocity.
New development or substantial improvement
in the 100-year floodplain may not increase erosive water velocity
on-site or off-site.
(4) Anchoring.
(A) All new construction and substantial improvements shall be 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 manufactured homes shall meet the anchoring standards of section
3.05.064.
(5) Construction materials and methods.
All new construction
and substantial improvement shall be constructed:
(A) With flood-resistant materials as specified in FEMA Technical Bulletin
TB 2-93, and utility equipment resistant to flood damage;
(B) Using methods and practices that minimize flood damage;
(C) 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, located two feet above the base flood
elevation; and
(D) Within zones AH or AO, so that there are adequate drainage paths
around structures on slopes to guide floodwaters around and away from
proposed structures.
(6) Elevation and floodproofing.
(See section
3.05.005 definitions for “basement,” “lowest floor,” “new construction,” “substantial damage” and “substantial improvement.”)
(A) Residential construction.
New or substantial improvement
shall have the lowest floor, including basement:
(i) In an AO zone, elevated above the highest adjacent grade to a height
equal to or exceeding two feet above the depth number specified in
feet on the FIRM, or elevated at least two feet above the highest
adjacent grade if no depth number is specified.
(ii)
In an A zone, elevated to or above two feet above the base flood elevation; said base flood elevation shall be determined by one of the methods in section
3.05.034(2) of this article.
(iii)
In all other zones, elevated to or above two feet above the
base flood elevation.
Upon the completion of construction of the foundation, and prior
to any additional construction, the elevation of the lowest floor
including basement shall be certified by a registered professional
engineer or surveyor, and verified by the city building official or
his designee to be properly elevated. Such certifications and verification
shall be provided to the floodplain administrator.
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(B) Nonresidential construction.
New or substantial improvement
shall either be elevated to conform with subsection (5) [(6)(A)] above,
or together with attendant utility and sanitary facilities:
(i) Be floodproofed below the elevation recommended under subsection
(A) above, so that the structure is watertight with walls substantially
impermeable to the passage of water;
(ii)
Have structural components capable of resisting hydrostatic
and hydrodynamic loads and effects of buoyancy; and
(iii)
Be certified by a registered professional engineer or architect
that the standards of this subsection (B) are satisfied. Such certification
shall be provided to the floodplain administrator.
(C) Enclosed areas below lowest floor.
All new construction
and substantial improvement with fully enclosed areas below the lowest
floor (excluding basements) that are usable solely for parking of
vehicles, building access or storage, 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 floodwater.
Designs for meeting this requirement shall follow the guidelines in
FEMA Technical Bulletins TB 1-93 and TB 7-93, and must exceed the
following minimum criteria:
(i) Have a minimum of two openings having a total net area of not less
than one square inch for every square foot of enclosed area subject
to flooding. The bottom of all openings shall be no higher than one
foot above grade. Openings may be equipped with screens, louvers,
valves or other coverings or devices provided that they permit the
automatic entry and exit of floodwater; and
(ii)
Be certified by a registered professional engineer or architect.
(D) Manufactured homes.
Manufactured homes shall also meet the standards in section
3.05.064.
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.326)
(a) All
new and replacement water supply and sanitary sewage systems shall
be designed and placed to minimize or eliminate:
(1) Infiltration of floodwaters into the systems; and
(2) Discharge from the systems into floodwaters.
(b) On-site
waste disposal systems shall be located to avoid impairment to them
or contamination from them during flooding and anchored in a manner
that will prevent flotation of the tank by means approved by the city
building official or his designated representative.
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.327)
(a) All
preliminary subdivision proposals shall identify the special flood
hazard area and the elevation of the base flood.
(b) All
subdivision plans will provide the elevation of proposed structure(s)
and pad(s). If the site is filled above the base flood elevation,
the lowest floor and pad elevations shall be certified by a registered
professional engineer or surveyor and provided to the floodplain administrator.
(c) All
subdivision proposals shall be consistent with the need to minimize
flood damage.
(d) All
subdivision proposals shall have public utilities and facilities such
as sewer, gas, electrical and water systems located and constructed
to minimize flood damage.
(e) All
subdivisions shall provide adequate drainage to reduce exposure to
flood hazards.
(f) All
subdivision plans shall identify at least one surveyed, permanently
installed monument. Additional monuments will be required for every
100 acres on the site described for development.
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.328)
(a) All
manufactured homes that are placed or substantially improved within
zones A1-30, AH, and AE on the community’s flood insurance rate
map, on sites located (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 a site upon which
a manufactured home has incurred “substantial damage”
as the result of a flood, shall be elevated on a permanent foundation
such that the lowest floor of the manufactured home is elevated two
feet above the base flood elevation and be securely fastened to an
adequately anchored foundation system to resist flotation, collapse,
and lateral movement.
(b) All manufactured homes to 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 flood insurance rate map that are not subject to the provisions of subsection
(a) will be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement, and be elevated so that the lowest floor of the manufactured home is elevated to two feet above the base flood elevation. Upon the completion of construction of the foundation, and prior to any additional construction, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, and verified by the city building official or his designee to be properly elevated. Such certification and verification shall be provided to the floodplain administrator.
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.329)
All recreational vehicles placed on sites within zones A1-30,
AH, and AE on the community’s flood insurance rate map will
either:
(1) Be
on the site for fewer than 180 consecutive days, and be fully licensed
and ready for highway use. 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; or
(2) Meet the permit requirements of division 2 of this article and the elevation and anchoring requirements for manufactured homes in section
3.05.064(a).
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.330)
Located within areas of special flood hazard established in section
3.05.007 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 potential, the following provisions apply:
(1) Prohibit
encroachments, including fill, new construction, substantial improvement,
and other new development.
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.331)
(a) The
floodplain administrator shall review permits for proposed construction
or other development to determine if it is proposed within a mudslide
area.
(b) Permits
shall be reviewed to determine that the proposed site and improvement
will be reasonably safe from mudslide hazards. Factors to be considered
in making this determination include but are not limited to:
(1) The type and quality of soils;
(2) Evidence of groundwater or surface water problems;
(3) Depth and quality of any fill;
(4) Overall slope of the site; and
(5) Weight that any proposed development would impose on the slope.
(c) Within
areas which may have mudslide hazards, the floodplain administrator
shall require that:
(1) A site investigation and further review be made by persons qualified
in geology and soils engineering;
(2) The proposed grading, excavation, new construction, and substantial
improvement be adequately designed and protected against mudslide
damages;
(3) The proposed grading, excavations, new construction, and substantial
improvement not aggravate the existing hazard by creating either on-site
or off-site disturbances; and
(4) Drainage, planting, watering, and maintenance not endanger slope
stability.
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.332)
(a) The
floodplain administrator shall require permits for proposed construction
and other development within all flood-related erosion-prone areas
as known to the community.
(b) Permit
applications shall be reviewed to determine whether the proposed site
alterations and improvements will be reasonably safe from flood-related
erosion and will not cause flood-related erosion hazards or otherwise
aggravate the existing hazard.
(c) If
a proposed improvement is found to be in the path of flood-related
erosion or would increase the erosion or would increase the erosion
hazard, such improvement shall be relocated or adequate protective
measures shall be taken to avoid aggravating the existing erosion
hazard.
(d) Within
zone E on the flood insurance rate map, a setback is required for
all new development from the ocean, lake, bay, riverfront or other
body of water to create a safety buffer consisting of a natural vegetative
or contour strip. This buffer shall be designated according to the
flood-related erosion hazard and erosion rate, in relation to the
anticipated useful life of structures, and depending upon the geologic,
hydrologic, topographic, and climatic characteristics of the land.
The buffer may be used for suitable open space purposes, such as for
agricultural, forestry, outdoor recreation and wildlife habitat areas,
and for other activities using temporary and portable structures only.
(Ordinance 966 adopted 10/20/04; 2004 Code, sec. 3.333)