FLOOD07489

• County: Statewide
• Basin: Statewide
• Title: Appeals, Revisions, and Amendments to Flood Insurance Maps - A Guide for Community Officials
• Date: 1/1/1990
• Prepared By: FEMA
• Floodplain - Doc Type: Historic FEMA Regulatory Floodplain Information

conditions, the requestor must verify
that revisions made to the floodplain
boundaries do not necessitate revisions
to the existing floodway boundaries.
When such floodway revisions are
necessary, the requestor may also be
required to submit a revised floodway
analysis.

In addition, the requestor must verify
that the new topographi c data do not
reflect hydraulic conditions that are
significantly different from those
modeled in the original hydraulic
analysis. When hydraulic conditions
have changed significantly, a new
hydraulic analysis may be required.

. Generally, when the requestor is
required to submit delineations of
floodplain boundaries for a flooding
source that was originally studied by
detailed methods, both the 100- and
SOO-year floodplain boundaries must be
submitted. If the original analyses for
that flooding source address only the
100-year flood, only the 10D-year
floodplain boundaries need be
submitted. For flooding sources
originally studied by approximate
methods, only tOO-year floodplain
boundaries need be submitted. The
boundaries should be shown on a
topographic map whose scale and
contour interval aTe sufficient to provide
reasonable accuracy.

. As noted in Paragraph 60.3(b)(7) of the
NFIP regulations, communities
participating in the NFIP must, as part of
their program responsibilities, ensure
that the flood-carrying capacity of any
altered or relocated watercourse is
maintained. Therefore, when a Map
Revision request is based on a channel
alteration or relocation, FEMA expects
that the affected community will ensure
that the channel is routinely maintained
so that its flood-carrying capacity is not
diminished by natural processes or
human activity.

However, if FEMA has any concerns
about the type and frequency of the

required maintenance activities for a
channel alteration or relocation project,
FEMA may, according to the provisions
of Paragraph6S.6(a)(12) of the NFIP
regulations, require that the community
submit specific documentation that
describes how the requirement stated in
Paragraph 60.3(b)(7) will be met.

. To support a request for a revision based
on the effects of earthfill levees or
similar structures, the requestor must
submit the data listed below to show
that the structural stability, operation,
and maintenance requirements of
Section 6S.10 of the NFIP regulations
have been met.

1. Freeboard -- For a riverine levee,
evidence that the levee provides a
minimum of 3 feet of freeboard
above the BFE

2. Freeboard -- For a coastal levee,
evidence that the levee provides a
minimum of 1 foot of freeboard
above the height of the 1-percent
wave or the maximum wave runup
(whichever is greater) associated
with the 100-year stillwater surge
elevation, but in no case less than 2
feet of freeboard above the 1 DO-year
stillwater surge elevation

3. Closures -- Evidence that shows that
all drainage structures that
penetrate the levee are fitted with
closure devices that are (1) structural
parts of the levee during operation
and (2) designed according to sound
engi neeri ng practice

4. Erosion Protection -- An engineering
analysis that demonstrates that no
appreciable erosion of the levee
embankment can be expected
during the 100- yearflood

5. Stability -- An engineering analysis
that evaluates the stability of the
levee embankment and foundation

6. Settlement -- An engineering
analysis that assesses the potential

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