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The measures outlined in this publication are designed
to address slow moving riverine flooding with minimal
debris—the objects floodwaters pick up, such as rocks, dirt,
sewage, ice, and tree branches. Most techniques presented
are not appropriate for high-risk flood hazard areas subject
to wave action (V zones and coastal A zones) or high
velocity flow areas (floodways, areas subject to alluvial fan
flooding, flash flood, mudslide, erosion, or ice jam).
Selection of Mitigation Measures
The ultimate goal of any mitigation measure is to reduce or
eliminate the potential of flood damage in a way that is cost
effective, complies with all applicable floodplain regulations,
and is acceptable to the homeowner in terms of appearance
and livability. The sections that follow include descriptions
of ten flood protection methods. Each description provides
information needed when considering how to protect your
home, including design considerations, costs, effectiveness,
limitations, and potential effect on flood insurance
premiums (additional detail on premium discounts is
provided on page 2 of this publication). Illustrations
that show how the methods are applied are also included.
In some cases, a single method may adequately address
your needs. In other cases, a combination of methods may
be best. Keep in mind, the flood protection method chosen
must meet the floodplain management requirements and/
or building codes of your local community. The methods
included in this publication may not be substituted for
bringing a building into compliance with local floodplain
regulations following a Substantial Damage or Substantial
Improvement determination by local community officials
except where noted.
As you will see in the sections that follow, different
flood protection methods protect your home in different
ways. For example, when you wet floodproof, you allow
floodwaters to enter your home, but prevent damage
below a specified elevation by using flood damage-resistant
materials and construction techniques. When you dry
floodproof your home, you use sealants, shields and other
measures to protect the part of your home below a specified
elevation by preventing water from entering the building.
Because some seepage is anticipated, sump pumps are
used to control the seepage and flood damage-resistant
materials are used to prevent damage where seepage is
likely to occur. When you protect your home with a levee
or floodwall, the top of the levee or floodwall is constructed
to a specified elevation. Other approaches include filling in
a basement or abandoning the bottom floor. For all of these
flood protection methods, the greatest flood damage and
flood insurance premium reductions will be achieved by
floodproofing to/or elevating to or above the BFE.
About the NFIP
In most communities throughout the United
States, construction in oodplains is governed by
combinations of Federal, State, and local regulation.
At the Federal level, FEMA administers the NFIP.
The NFIP is a voluntary program for communities.
Its goal is to reduce the loss of life and the damage
caused by ooding, to help the victims of oods,
and to lower the costs of ood damage borne by the
taxpayer. Communities that participate in the NFIP
take action in several ways:
• Guide future development away from ood
hazard areas.
• Require that new buildings, Substantially
Improved existing buildings, and repair of
Substantially Damaged existing buildings in
the SFHA be constructed in compliance with
oodplain management ordinance, regulation, or
provisions of the building code intended to reduce
ood damage.
Dry oodproong: Sealing your home to prevent
oodwaters from entering.
Wet oodproong: Making portions of your home
resistant to ood damage and allowing water to
enter during ooding.
Flood damage-resistant material: Any building
product (material, component, or system) capable
of withstanding direct and prolonged contact with
oodwaters without sustaining signicant damage.
Examples may include ood damage-resistant
building nish materials such as non-paper-faced
gypsum board and terrazzo tile ooring versus
traditional drywall and carpeted ooring.
Substantial Damage: Damage of any origin
sustained by a building whereby the cost of restoring
the building to its before-damaged condition would
equal or exceed 50 percent of the market value of
the building before the damage occurred.
Substantial Improvement: Any reconstruction,
rehabilitation, addition, or other improvement of a
building, the cost of which equals or exceeds 50
percent of the market value of the building before
the start of construction of the improvement.