Flood Map Revision Processes
With over 19,000 communities participating in the National Flood Insurance Program (NFIP), it is a challenge to keep flood hazard maps up to date. There are three primary methods by which a community's flood hazard maps are updated. The first is through a Federal Emergency Management Agency (FEMA)-initiated study or restudy of flood hazards and subsequent revision of the NFIP flood maps. The second method is through a community-initiated revision under Part 65 of the NFIP regulations, and the third is through the Cooperating Technical Partners (CTP) initiative. Each of these methods is discussed briefly below.
FEMA-Initiated Map Updates
Each year, FEMA initiates studies and restudies
of flood hazards in communities across the
U.S. for the creation, as well as the revision,
of community flood hazard maps. Because of
funding constraints, however, FEMA can study
or restudy only a limited number of communities
each year. As a result, FEMA prioritizes study
and restudy needs based on a cost-benefit approach
whereby the highest priority is given to studies
where development is greatest and where the
maps are most outdated. FEMA has a special
task force that reviews community mapping needs
and captures their findings in the Mapping
Needs Update Support System. For more information
about the Mapping Needs Update Support System,
please visit the FEMA website at http://www.fema.gov/fhm/mn_main.shtm.
Community-Initiated Map Revisions Through
Part 65 of the NFIP Regulations
The flood hazard maps must present flood risk
information that is correct and up to date
to ensure that they provide a sound basis for
floodplain management and insurance rating.
FEMA relies heavily on communities to provide
notification of changing flood hazard information
and to submit the technical support data needed
to reflect the updated flood hazards on the
NFIP maps. Although revisions may be requested
to change any of the information presented
on the NFIP maps, FEMA generally will not revise
an effective map unless the changes involve
modifications to Special Flood Hazard Areas
(1% annual chance floodplains or flood elevations).
Requests for revisions that involve other information
(e.g., roads or corporate limits) will typically
be filed for future use. To assist in the map
revision process, FEMA has developed Application/Certification
Forms and Instructions for Revisions to National
Flood Insurance Program Maps. These Application/Certification
Forms and Instructions can be downloaded from
the FEMA website at http://www.fema.gov/fhm/frm_form.shtm.
Community-Initiated Map Revisions Through
the CTP Initiative
The CTP initiative is an innovative program
created to foster partnerships between FEMA
and participating NFIP communities, as well
as regional and State agencies that have the
capability to become more active participants
in the FEMA Flood Hazard Mapping Program. FEMA
is seeking qualified partners to collaborate
in maintaining up-to-date flood maps. Communities
can participate in a number of ways which may
include development of updated hydrologic and
hydraulic modeling and mapping, refinement
of approximate Zone A floodplain boundaries,
digital base map data sharing, and digital
topographic data development. More information
on the CTP initiative, including funding options
and the steps to become a CTP, is available
at http://www.fema.gov/fhm/ctp_main.shtm.
Map Revision Processing Options
Once initiated, FEMA will process a request
to revise the flood hazard maps based on as-built
conditions by one of two methods - Physical
Map Revision (PMR) or Letter of Map Revision
(LOMR). A PMR is an action whereby
one or more map panels are physically revised
and republished. A PMR is used to change flood
risk zones, floodplain and/or floodway delineations,
flood elevations, and/or planimetric features.
To ensure that those affected by the PMR have
the opportunity to provide input, a PMR has
procedures that include a community comment
period and a 6-month compliance period to update
ordinances while the new maps are printed and
distributed. Because of the large amount of
flood hazard information that is incorporated
into the maps and the number of people that
will be affected by that information, a PMR
can take as long as 18 months to complete.
FEMA charges the requester of a PMR a fee for
review of the data submitted in support of
certain types of requests such as those concerning
structural measures. PMRs must be requested
by the Chief Executive Officer (CEO) of the
community because the community is responsible
for adoption of the revised flood hazard information
into their specific floodplain management ordinances
and regulations.
A LOMR is a document that officially revises a portion of the effective NFIP map according to requirements and procedures outlined in Part 65 of the NFIP regulations. A LOMR allows FEMA to revise flood hazard information on an NFIP map via letter without physically revising and reprinting the entire map panel. This process typically takes less time and is less expensive than a PMR. LOMRs include the revised portion of the flood hazard map, affected flood profiles, and floodway data tables from the Flood Insurance Study (FIS) report as attachments to the letter. LOMRs are essentially like PMRs in that they are used to change flood risk zones, floodplain and/or floodway delineations, flood elevations, and/or planimetric features; however, because of their limited distribution, LOMRs are primarily intended for small areas of change and areas where flood hazards are typically decreasing. FEMA charges the requesters of LOMRs a fee for review of the flood hazard data submitted in support of certain types of requests such as those concerning structural measures. As with PMRs, a LOMR must be requested through the CEO of the community because the community is responsible for the adoption of the revised flood hazard information into the community's floodplain management ordinances and regulations.
Property owners or other persons who wish to follow the progress of a particular PMR, LOMR, or other map revision are advised to consult the community's Floodplain Administrator. This is the local official who keeps all of the community's flood hazard maps and FIS report, and who corresponds with FEMA at various stages of the revision process. Often this is an official such as the City/County Engineer or the Director of Planning or Zoning Administrator. The status of ongoing map revisions can also be checked on the FEMA website at http://www.fema.gov/fhm/st_main.shtm, or by calling the FEMA Map Assistance Center toll free at 1-877-FEMA MAP or 1-877-336-2627.
