Federal Emergency Management Agency Floodplain Management
Bulletin 1 — 98

For Zones B, C, and X:

The NFIP floodplain management criteria do not require the use of BFE and floodway data
from a draft or preliminary FIS under 44 CFR 60.3(b)(4) for an area or areas within Zones B,
C, or X on the community’s FIRM that are being revised to Zone AE, A1-30, AH, AO, VE, or
1-30. While FEMA can not mandate or require a community to use the information
contained in the draft or preliminary FIS pertaining to areas designated as Zone B, C, or X
as available data or use the data at the time FEMA issues the LFD to the community, FEMA
encourages communities to reasonably utilize this information to ensure that the health,
safety, and property of their citizens are protected.

Important Note to Communities:

“In order to participate in the NFIP, all communities must initially adopt a resolution or
ordinance which expresses a “commitment to recognize and evaluate flood hazards
in all official actions and: to take such other official action as reasonably necessary to
carry out the objectives of the program” [44 CFR 59.22(a)(8)]. This is in addition to
the general requirement that the community “take into account flood hazards to the

| extent that they are known in all official actions relating to land management and use”
[44 CFR 60.1(c)]. When communities receive a draft or preliminary FIS, communities
have a responsibility to evaluate and prudently use this information for actions in the

‘floodplain to ensure that the health, safety, and property of their citizens are pro-
tected. Neglecting to take into consideration the information provided in a draft or
preliminary FIS and not taking reasonable actions to ensure the safety of lives and
property may subject the community to potential liability when flooding occurs.

Inthe interest of sound floodplain management and to anticipate the impacts of fu-
ture development on flood elevations, communities also can, at their discretion, adopt
more restrictive floodplain management requirements. For example, the community
can ‘require that new or substantially improved buildings be elevated or floodproofed
to one or more feet above the BFEs provided in the draft or preliminary FIS. This
more restrictive requirementis generally referred to as “freeboard”.

Ordinance Requirements: Adoption of the Data

For Zone A:

When all appeals have been resolved and a notice of final flood elevation determination has
been provided in a LFD, communities are required to use the BFE and floodway data for
regulating floodplain development in accordance with 44 CFR 60.3(b)(4) since the data
represents the best data available. This includes meeting the standards of Subparagraphs
60.3(c), (d), and/or (e). Communities must regulate floodplain development using the data
in the FIS under Subparagraph 60.3(b)(4) until such time as the community has adopted the
effective FIRM and FIS.

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Federal Emergency Management Agency Floodplain Management
Bulletin 1-98

Further Information

Managing Floodplain Development in Approximate Zone A Areas, A Guide For Obtaining
and Developing Base (100-year) Flood Elevations, FEMA 265, July 1995. Additional

guidance pertaining to obtaining and developing BFEs in Zone A can be found in this
publication. To obtain a copy of this publication, see the section on Ordering Information on
the following page.

Comments

Any comments on the Floodplain Management Bulletin should be directed to:

FEMA

Mitigation Directorate
500 C St., SW
Washington, D.C. 20472

Ordering Information

Copies of Floodplain Management Bulletins are available from various sources.

° Floodplain Management Bulletins can be ordered from the FEMA Distribution Facility.
Use of FEMA Form 60-8 will result in a more timely delivery from the warehouse. The
form can be obtained from FEMA regional offices or your state’s Office of Emergency
Management. Send publication requests to FEMA Distribution Facility, P.O. Box 2012,
Jessup, MD 20794-2012. FEMA's Distribution Facility also accepts telephone requests
(1-800-480-2520) and facsimile requests (301-497-6378).

« FEMA's Fax-On-Demand system: Call 202-646-FEMA (3362) and follow the directions.

e FEMA World Wide Web Page: http:/Avww.fema.gov/mit/

° Copies of the Floodplain Management Bulletins can be obtained from the appropriate
FEMA regional office.

Graphic design based on the Japanese print The Great Wave Off Kanagawa, by Katsushika Hakusai (1760-1849), Asiatic
Collection, Museum of Fine Arts, Boston.

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Federal Emergency Management Agency Floodplain Management
Bulletin 1-98

For Zones AE, A1-30, AH, AO, VE, and V1-30:

The NFIP floodplain management criteria do not require communities to use BFE and

flood way data from a draft or preliminary Flood Insurance Restudy in Zones AE, A1-30,
AH, AO, VE, and V1-30 in lieu of using the BFE and floodway data contained in an existing
effective FIS and FIRM. Because communities are afforded the opportunity to appeal BFE
data from a restudy in accordance with Section 1363 of the National Flood Insurance Act of
1968, as amended, a presumption of validity is given to existing effective BFE data that has
gone through the formal statutory appeals process and which has been adopted by the
community.

However, in cases where BFEs increase in the restudied area, communities have the
responsibility to ensure that new or substantially improved structures are protected,
particularly if the increases in BFEs are significant. While FEMA can not mandate or require
a community to use BFE and floodway data in a draft or preliminary FIS as available data or
to use the data at the time FEMA issues the LFD to the community, FEMA encourages
communities to reasonably utilize this information in instances where BFEs increase and
floodways are revised to ensure that the health, safety, and property of their citizens are
protected.

In cases where BFEs decrease, the community should not use this information to regulate
floodplain development until the LFD has been issued or at least until all appeals have been
resolved. If the draft or preliminary FIS provides information that BFEs are decreasing, but
a valid appeal actually results in higher BFEs, the community could place its citizens at a
greater flood risk by using the draft or preliminary FIS to regulate floodplain development.
Also, these structures could be subject to increased flood insurance premiums.

In communities where floodways have not been designated for all or some of the flooding
sources, but BFEs have been provided, communities are required to apply the criteria at 44
CFR 60.3(c)(10). This provision requires that:

Until a regulatory floodway is designated, no new construction, substantial
improvements, or other development shall be permitted unless it is
demonstrated that the cumulative effect of the proposed. development, when
combined with all other existing and anticipated development, will not
increase the water surface elevation of the base flood more than one foot at
any point within the community. [44 CFR 60.3(c)(10)]

However, if a draft or preliminary FIS has designated floodways where none had previously
existed, communities should reasonably utilize this data in lieu of applying the encroach-
ment performance standard of 44 CFR 60.3(c)(10) since the data in the draft or preliminary
FIS represents the best data available. By utilizing the floodway data from a draft or Pre-
liminary FIS, communities avoid the expense of conducting the hydraulic analysis necessary
to demonstrate compliance with 60.3 (c)(10). In addition, communities can minimize flood
damages by ensuring that the flood carrying capacity of the floodway is preserved since
obstruction of floodways can significantly increase potential flooding upstream.

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Federal Emergency Management Agency Floodplain Management
Bulletin 1 — 98

For Zones AE, A1-30, AH, AO, VE, V1-30, B, C, and X:

Communities are given six months from the date of the LFD in which to adopt the revised
FIS and FIRM. This is in keeping with FEMA's statutory obligation to provide a reasonable
time for the community to adopt floodplain management regulations consistent with the final
flood elevation determinations. Subparagraph 44 CFR 59.24(a) of the NFIP Regulations
provides for a six month compliance period in which the community must adopt the effective
FIS and FIRM and amend existing regulations to incorporate any additional requirements
under 44 CFR 60.3.

Floodplain management ordinances generally contain a section entitled "Basis for Establish-
ing the Areas of Special Flood Hazard” in which the current effective FIS and FIRM are
cited. Language in the ordinance may include any subsequent amendments thereto (i.e., to
include any subsequent revised FIS and FIRM); however, this language should not be used
as the basis for a community to use the preliminary FIS prior to the issuance of the LFD. Ifa
community chooses to use BFE and floodway data from a preliminary FIS prior to the LFD
being issued or use the data after a LFD is issued but before the effective date of the FIS
and FIRM, it is advised that the community adopt this information before its use.

Advisory Flood Hazard Data:

FEMA may issue advisory flood hazard data in certain situations. A major flood dis-
aster, such as from a coastal storm or from a failure of a flood protection system, may
result in a community’s effective FIS and FIRMs underestimating the extent of the
flood hazard and the risk of flooding. FEMA may undertake a post-flood survey to
document additional areas of the community subject to the base flood (1% annual
chance) and to develop estimated flood elevations which will be used to reanalyze and
revise the effective FIS and FIRMs. The information from the post-flood survey will be
provided to communities as advisory information when the analyses indicates that the
effective FIS and FIRMs are inaccurate. Also, communities may obtain or develop
flood hazard data that indicates existing flood hazard areas that shows a greater risk
than what is in the effective FIS and on the FIRM.

Communities are advised to prudently use this information for regulating floodplain
development. When communities receive advisory flood hazard information or have
evidence that there is an increased flood hazard risk, communities have a responsibil-
ity to evaluate and prudently use this information for actions in the floodplain to ensure
that structures are not vulnerable to flood damage. If a community chooses to use
this information, it is advised that the community formally adopt the information.
Neglecting to take into consideration advisory or other flood hazard information and not
taking reasonable actions to ensure that the health, safety, and property of their citi-
zens are protected may subject the community to potential liability when flooding

occurs.

Page 6 of 8


Floodplain
Management
Bulletin 1-98

Use Of Flood Insurance Study (FIS) Data
As Available Data

Floodplain Management Bulletin 1-98 provides guidance on the use of FEMA draft or
preliminary Flood Insurance Study data as “available data” for regulating floodplain
development. The bulletinincludes: ~

Introduction ..
Background .
NFIP Requirements: Use of Draft or Preliminary FIS Data . 2
Ordinance Requirements: Adoption of Data .

Insurance Implications
Further Information...

Introduction

When areas have been designated as special flood hazard areas on the community's Flood
Hazard Boundary Map (FHBM) or Flood Insurance Rate Map (FIRM) and no Base Flood
Elevations (BFEs) or an identified floodway have been developed, communities are required
to apply the provisions of 44 Code of Federal Regulations 60.3(b)(4). Subparagraph
60.3(b)(4) requires that communities:

Obtain, review and reasonably utilize any base flood elevation and
floodway data available from a Federal, State, or other source... [44
CFR 60.3(b)(4)]

Data obtained are to be used by communities as criteria for requiring that new construction
and substantialimprovements have their lowest floors elevated to or above the BFE (non-
residential structures can also be floodproofed to or above the BFE) and for prohibiting any
encroachments in a floodway that would result in any increase in flood levels during
occurrence of the base flood discharge. The data obtained should be used as long as they
reasonably reflect flooding conditions expected during the base flood, are not known to be
scientifically or technically incorrect, and represent the best data available. Data froma
draft or preliminary Flood Insurance Study (FIS) constitute available data under 44 CFR
60.3(b)(4). This bulletin provides guidance on the use of FEMA draft or preliminary FIS data
as available data for regulating floodplain development.

\ Federal Emergency Management Agency
} Mitigation Directorate and the FMB-1
Federal Insurance Administration 1/98



Federal Emergency Management Agency Floodplain Management
Bulletin 1-98

Insurance Implications

Zone A:

For a new or substantially improved structure, communities can use information from a
draft or preliminary FIS for completing the Elevation Certificate in Zone A areas. The flood
insurance policies for new or substantially improved structures in Zone A that are rated
using BFE data from a draft or preliminary FIS will often qualify for significantly lower
insurance rates than policies that are rated without a BFE.

Zones AE, A1-30, AH, AO, VE, and V1-30:

For flood insurance rating purposes, in Zones AE, A1-30, AH, AO, VE, or V1-30, new or
substantially improved structures are rated based on the BFE and FIRM zone in effect on
the date of construction until the revised FIRM becomes effective. This is the case
regardless of whether the preliminary FIS indicates that the proposed BFEs will increase or
decrease.

If a community chooses to use proposed BFEs from a draft or a preliminary FIS for a new or
substantially improved structure, the flood insurance rate is still based on the BFE and FIRM
Zone in effect on the date of construction. The flood insurance rate will be based on the
elevation difference between the BFE and FIRM Zone in effect and the elevation of the
lowest floor. Therefore, if a new or substantially improved structure is built to the proposed
BFE from a draft or preliminary FIS and this BFE is higher than the BFE in effect, the flood
insurance rate may be significantly lower. However, a new or substantially improved
structure built to the proposed BFE that is lower than the BFE in effect may result in a
significantly higher flood insurance rate. In this case, the insured will qualify for a premium
pro rata refund once the revised FIRM is effective.

Zones B, C, and X:

For flood insurance rating purposes, new or substantially improved structures are rated
based on the FIRM Zone in effect (i.e., Zone B, C, or X) on the date of start of construction.
If a community chooses to use proposed BFEs from a draft or preliminary FIS for a new or
substantially improved structure, the flood insurance rate is still based on the FIRM Zone in
effect (i.e., Zone B, C or X) on the date of construction.

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Federal Emergency Management Agency Floodplain Management
Bulletin 1-98

Background

Flood Insurance Studies (FIS) use detailed hydrologic and hydraulic analyses to model the
1% annual chance flood event, determine BFEs, and designate floodways and risk zones
(Zones AE, A1-30, AH, AO, VE, and V1-30). The flood hazard data are portrayed in tabular
fashion in the FIS narrative and graphically as flood profiles that are attached to the
narrative. They are portrayed planimetrically on the FIRM. Over 10,000 communities have
now been provided detailed FISs and issued FIRMs that include BFEs for Zones AE, A1-30,
AH, AO, VE, and V1-30.

A draft FIS can be prepared by a study contractor to FEMA under 44 CFR Part 66 or by
appellants under 44 CFR Part 65 for the purpose of establishing or revising BFE and
floodway data. FEMA reviews and modifies, as appropriate, the draft FIS to ensure it
complies with established NFIP criteria. Once FEMA has reviewed and approved the draft
FIS, FEMA releases the information to the public as a Preliminary FIS and FIRM for review
and comment during a statutory 90-day appeal period in accordance with 44 CFR Part 67.
Until such time as the 90-day appeal period is completed and a notice of final flood elevation
determination [Letter of Final Determination (LFD)] has been provided, the BFE and
floodway data in the FIS are considered preliminary and subject to change.

Due to the cost of developing detailed flood hazard data, not all floodplains can be studied
using detailed methodologies. A primary factor FEMA uses in it’s system for prioritizing
floodplain studies or restudies with BFEs and floodway data is whether the floodplains of the
flooding sources are currently or are projected to be subject to development pressure. In
NFIP communities where there are few existing buildings in the floodplain and minimal
development pressure, FEMA does not prepare a detailed FIS. These communities are
converted to the Regular Program with a FIRM in which all of the special flood hazard areas
are designated Zone A without BFEs using approximate methodologies. Most NFIP
communities will have FIRMs that include a combination of special flood hazard areas that
have been studied in detail with BFEs and floodway data and special flood hazard areas
that have been studied using approximate methods which have been designated Zone A.

National Flood Insurance Program (NFIP) Requirements:
Use of Draft or Preliminary FIS Data

For Zone A:

For Zone A areas designated on the community's effective FHBM or FIRM, the BFE and
floodway data from a draft or preliminary FIS constitute available data under Subparagraph
60.3(b)(4). The requirement at Subparagraph 60.3(b)(4) is an important floodplain manage-
ment tool for reducing flood damages in areas where a detailed engineering study to
develop BFEs and designate floodways on streams has not been conducted. Communities
are required to reasonably utilize the data from a draft or preliminary FIS under the section
of their ordinance that applies to this paragraph. A community is allowed discretion in using

Page 2 of 8


Federal Emergency Management Agency Floodplain Management
Bulletin 1 — 98

this data only to the extent that the technical or scientific validity of the data in the draft or
preliminary FIS is questioned.

When all appeals have been resolved and a notice of final flood elevation determination has
been provided in a LFD, communities are required to use the BFE and floodway data for
regulating floodplain developmentin accordance with 44 CFR 60.3(b)(4) since the data
represents the best data available. This includes meeting the standards at 44 CFR 60.3(c),
and (d) which includes the requirement that new construction, substantial improvements,
and other development have their lowest floor elevated to or above the BFE (non-residential
structures can also be floodproofed to or above the BFE). Communities must regulate
floodplain development using the data in the FIS under 60.3(b)(4) until such time as the
community has adopted the revised FIRM and FIS.

In Zone A areas, the rationale for requiring reasonable utilization of BFE and floodway data
in a draft or preliminary FIS is premised on the absence of other BFE or floodway data and
the need to protect new or substantially improved structures from flood damage until such
time as appeals are completed and the BFEs and/or floodway are incorporated into the local
ordinance. The use of the qualifier "reasonable" at 44 CFR 60.3(b)(4) reflects FEMA's
statutory obligation to provide the public an opportunity to appeal the proposed elevation
data.

If a community decides not to use the BFE or floodway data in the draft or preliminary FIS
because it is questioning the data through a valid appeal, the community must continue to
ensure that buildings are constructed using methods and practices that minimize flood
damages in accordance with the floodplain management requirements under
subparagraphs 60.3(a)(3) and (4).

e Subparagraph 60.3(a)(3) requires communities to review permit applications to
determine whether proposed building sites are reasonably safe from flooding. Ifa
proposed building site is floodprone, communities are to require that new construction
and substantial improvements be adequately anchored, use flood resistant materials, be
constructed to minimize flood damages, and have attendant utilities protected during the
conditions of flooding.

¢ Subparagraph 60.3(a)(4) requires communities to review subdivision proposal and other
proposed new development, including manufactured home parks or subdivisions, to
determine whether proposals will be reasonably safe from flooding. If a subdivision
proposal or other proposed new developmentis floodprone, communities are required
to review such proposals to assure potential flood damages are minimized, utilities are
constructed to minimize or eliminate damages, and adequate drainage is provided to
reduce the exposure to flood hazards.

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