In all areas of special flood hazard the following
standards are required.
In all areas of special flood hazard where base flood elevation data has been provided as set forth in §
92-6, Basis for establishing areas of special flood hazard, and §
92-15, Use of other base flood and floodway data, the following standards are required.
New construction and substantial improvements
of any residential structure shall:
A. Have the lowest floor, including basement or cellar,
elevated to or above the base flood elevation.
B. Have fully enclosed areas below the lowest floor that
are subject to flooding 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 licensed professional engineer or architect or meet
or exceed the following minimum criteria:
(1) 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 shall be provided.
(2) The bottom of all such openings shall be no higher
than one foot above the lowest adjacent finished grade.
(3) Openings may be equipped with louvers, valves, screens
or other coverings or devices, provided that they permit the automatic
entry and exit of floodwaters.
New construction and substantial improvements
of any commercial, industrial or other nonresidential structure, together
with attendant utility and sanitary facilities, shall either have
the lowest floor, including basement or cellar, elevated to or above
the base flood elevation or be floodproofed so that the structure
is watertight below the base flood level with walls substantially
impermeable to the passage of water. All structural components located
below the base flood level must be capable of resisting hydrostatic
and hydrodynamic loads and the effects of buoyancy.
A. If the structure is to be elevated, fully enclosed
areas below the base flood elevation shall be designed to automatically
(without human intervention) allow for the entry and exit of floodwaters
for the purpose of equalizing hydrostatic flood forces on exterior
walls. Designs for meeting this requirement must either be certified
by a licensed professional engineer or a licensed architect or meet
the following criteria:
(1) 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 shall be provided.
(2) The bottom of all such openings shall be no higher
than one foot above the lowest adjacent finished grade.
(3) Openings may be equipped with louvers, valves, screens
or other coverings or devices, provided that they permit the automatic
entry and exit of floodwaters.
B. If the structure is to be floodproofed:
(1) A licensed 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
to make the structure watertight with walls substantially impermeable
to the passage of water, with structural components having the capability
of resisting hydrostatic, and hydrodynamic loads and effects of buoyancy.
(2) A licensed professional engineer or licensed land
surveyor shall certify the specific elevation, in relation to mean
sea level, to which the structure is floodproofed.
C. The local administrator shall maintain on record a
copy of all such certificates noted in this section.
New construction or substantial improvements of structures, including manufactured homes, shall have the lowest floor, including basement, elevated to or above the base flood elevation as may be determined in §
92-15 or two feet above the highest adjacent grade where no elevation data is available.
A. New construction or substantial improvements of structures,
including manufactured homes, shall have the lowest floor, including
basement, elevated at least two feet above the highest adjacent grade
next to the proposed foundation of the structure.
B. Fully enclosed areas below the lowest floor that are
subject to flooding shall be designed to automatically (without human
intervention) allow for the entry and exit of floodwaters for the
purpose of equalizing hydrostatic flood forces on exterior walls.
Designs for meeting this requirement must either be certified by a
licensed professional engineer or a licensed architect or meet the
following criteria:
(1) 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 shall be provided.
(2) The bottom of all such openings shall be no higher
than one foot above the lowest adjacent finished grade.
(3) Openings may be equipped with louvers, valves, screens
or other coverings or openings, provided that they permit the automatic
entry and exit of floodwaters.
Located within areas of special flood hazard are areas designated as floodways (see definition, §
92-4). The floodway is an extremely hazardous area due to high-velocity floodwaters carrying debris and posing additional threats from potential erosion forces. When floodway data is available for a particular site as provided by §§
92-6 and
92-15, all encroachments, including fill, new construction, substantial improvements and other development are prohibited within the limits of the floodway unless a technical evaluation demonstrates that such encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.