In all areas of special flood hazards the following standards
are required:
A. Anchoring.
1. 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.
2. All manufactured homes shall meet the anchoring standards of Section
15.24.190.
B. Construction
Materials and Methods. All new construction and substantial improvement
shall be constructed:
1. With
flood resistant materials as specified in FEMA Technical Bulletin
TB 2-93, and utility equipment resistant to flood damage;
2. Using
methods and practices that minimize flood damage;
3. 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; and if
4. 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.
C. Elevation
and Floodproofing. (See Section 15.25.050 definitions for "basement,"
"lowest floor," "new construction," "substantial damage" and "substantial
improvement.")
1. Residential
construction, new or substantial improvement shall have the lowest
floor, including basement:
a. In an AO zone, elevated above the highest adjacent grade to a height
equal to or exceeding 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. In AO zones without velocity the lowest
floor shall be elevated above the highest adjacent grade to a height
exceeding the depth number specified in feet on the FIRM by at least
two feet, or elevated at least four feet above the highest adjacent
grade if no depth number is specified.
b. In an A zone, elevated to at least two feet above the base flood elevation; said base flood elevation shall be determined by one of the methods in Section
15.24.140(B) of this chapter.
c. In all other zones, elevated to at least two feet above the base
flood elevation.
Upon the completion of the structure, the elevation of the lowest
floor including basement shall be certified by a registered professional
engineer or surveyor, and verified by the building official to be
properly elevated. Such certification and verification shall be provided
to the floodplain administrator.
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2. Nonresidential
construction new or substantial improvement shall either be elevated
to conform with Section 15.24.160(C)(1) or together with attendant
utility and sanitary facilities:
a. Be floodproofed below the elevation recommended under Section 15.24.160(C)(11)
so that the structure is watertight with walls substantially impermeable
to the passage of water;
b. Have structural components capable of resisting hydrostatic and hydrodynamic
loads and effects of buoyancy; and
c. Be certified by a registered professional engineer or architect that
the standards of this Section 15.24.160(C)(2) are satisfied. Such
certification shall be provided to the floodplain administrator.
3. 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:
a. 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; or
b. Be certified by a registered professional engineer or architect.
4. Manufactured homes shall also meet the standards in Section
15.24.190.
(Ord. 279 § 1, 2002)
Located within areas of special flood hazard established in Section
15.24.070 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:
A. Prohibit
encroachments, including fill, new construction, substantial improvement,
and other new development unless certification by a registered professional
engineer is provided demonstrating that encroachments shall not result
in any increase in (the base) flood elevation during the occurrence
of the base flood discharge.
B. If Section
15.24.230(A) is satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of Sections
15.24.160 through
15.24.210.
(Ord. 279 § 1, 2002)