Flood Hazard Assessments and Mapping Requirements

76. What is the difference between an FHBM and a FIRM?
An FHBM is based on approximate data and identifies, in general, the SFHAs within a community. It is used in the NFIP's Emergency Program for floodplain management and insurance purposes. A FIRM usually is issued following a flood risk assessment conducted in connection with the community's conversion to the NFIP's Regular Program. If a detailed assessment, termed a Flood Insurance Study (FIS), has been performed, the FIRM will show base flood elevations and insurance risk zones in addition to floodplain boundaries. The FIRM may also show a delineation of the regulatory floodway. (See the answer to Question 80 for a description of "regulatory floodway.") After the effective date of the FIRM, the community's floodplain management ordinance must be in compliance with appropriate Regular Program requirements. Actuarial rates, based on the risk zone designations shown on the FIRM, are then applied for newly constructed, substantially improved, and substantially damaged buildings.

77. How are flood hazard areas and flood levels determined?
Flood hazard areas are determined using statistical analyses of records of riverflow, storm tides, and rainfall; information obtained through consultation with the community; floodplain topographic surveys; and hydrologic and hydraulic analyses. The FIS covers those areas subject to flooding from rivers and streams, along coastal areas and lake shores, or shallow flooding areas.

78. What is the role of the local community in its flood hazard assessment?
In conducting a FIS, FEMA considers all available information for use in the study. Public meetings are usually held with community officials and other interested parties in an effort to obtain all relevant information to help ensure accurate study results. FEMA also works closely with community officials before and during the study to describe technical and administrative procedures and to obtain community input before the FIRM and collateral FIS report are published. Before the FIS is initiated, FEMA representatives, the selected contractor, and community officials meet to discuss the areas to be studied and the level of study required. This meeting is called a "time and cost" meeting.

79. What flood hazard zones are shown on the Flood Insurance Rate Map and what do they mean?
Several areas of flood hazard are commonly identified on the FIRM. One of these areas is the SFHA, which is defined as the area that will be inundated by the flood event having a 1-percent chance of being equaled or exceeded in any given year. The 1-percent-annual-chance flood is also referred to as the base flood or 100-year flood. SFHAs are labeled as Zone A, Zone AO, Zone AH, Zones A1-A30, Zone AE, Zone 99, Zone AR, Zone AR/AE, Zone AR/AH, Zone AR/AO, Zone AR/A1-A30, Zone AR/A, Zone V, Zone VE, and Zones V1-V30. Moderate flood hazard areas, labeled Zone B or Zone X (shaded), are also shown on the FIRM, and are the areas between the limits of the base flood and the 0.2-percent-annual-chance (or 500-year) flood. The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2-percent-annual-chance flood, are labeled Zone C or Zone X (unshaded). The definitions for the various flood hazard areas are presented below.

Zone V: Areas along coasts subject to inundation by the 1-percent-annual-chance flood event with additional hazards associated with storm-induced waves. Because detailed hydraulic analyses have not been performed, no base flood elevations or depths are shown. Mandatory flood insurance purchase requirements apply.

Zones VE and V1-V30: Areas along coasts subject to inundation by the 1-percent-annual-chance flood event with additional hazards due to storm-induced velocity wave action. Base flood elevations derived from detailed hydraulic analyses are shown within these zones. Mandatory flood insurance purchase requirements apply. (Zone VE is used on new and revised maps in place of Zones V1-V30.)

Zone A: Areas subject to inundation by the 1-percent-annual-chance flood event. Because detailed hydraulic analyses have not been performed, no base flood elevation or depths are shown. Mandatory flood insurance purchase requirements apply.

Zones AE and A1-A30: Areas subject to inundation by the 1-percent-annual-chance flood event determined by detailed methods. Base flood elevations are shown within these zones. Mandatory flood insurance purchase requirements apply. (Zone AE is used on new and revised maps in place of Zones A1-A30.)

Zone AH: Areas subject to inundation by 1-percent-annual-chance shallow flooding (usually areas of ponding) where average depths are between one and three feet. Base flood elevations derived from detailed hydraulic analyses are shown in this zone. Mandatory flood insurance purchase requirements apply.

Zone AO: Areas subject to inundation by 1-percent-annual-chance shallow flooding (usually sheet flow on sloping terrain) where average depths are between one and three feet. Average flood depths derived from detailed hydraulic analyses are shown within this zone. Mandatory flood insurance purchase requirements apply.

Zone AR: Areas that result from the decertification of a previously accredited flood protection system that is determined to be in the process of being restored to provide base flood protection. Mandatory flood insurance purchase requirements apply.

Zone A99: Areas subject to inundation by the 1-percent-annual-chance flood event, but which will ultimately be protected upon completion of an under-construction Federal flood protection system. These are areas of special flood hazard where enough progress has been made on the construction of a protection system, such as dikes, dams, and levees, to consider it complete for insurance rating purposes. Zone A99 may only be used when the flood protection system has reached specified statutory progress toward completion. No base flood elevations or depths are shown. Mandatory flood insurance purchase requirements apply.

Zones B, C, and X: Areas identified in the community FIS as areas of moderate or minimal hazard from the principal source of flood in the area. However, buildings in these zones could be flooded by severe, concentrated rainfall coupled with inadequate local drainage systems. Local stormwater drainage systems are not normally considered in the community's FIS. The failure of a local drainage system creates areas of high flood risk within these rate zones. Flood insurance is available in participating communities but is not required by regulation in these zones. (Zone X is used on new and revised maps in place of Zones B and C.)

Zone D: Unstudied areas where flood hazards are undetermined, but flooding is possible. No mandatory flood insurance purchase requirements apply, but coverage is available in participating communities.

Zones AR/AE, AR/AH, AR/AO, AR/A1-A30, AR/A: Dual flood zones that, because of flooding from other water sources that the flood protection system does not contain, will continue to be subject to flooding after the flood protection system is adequately restored. Man-datory flood insurance purchase requirements apply.

80. What is a regulatory floodway and who designates it?
The regulatory floodway, which is adopted into the community's floodplain management ordinance, is the stream channel plus that portion of the overbanks that must be kept free from encroachment in order to discharge the 1-percent-annual-chance flood without increasing flood levels by more than 1.0 foot (some states specify a smaller allowable increase). The intention of the floodway is not to preclude development. Rather, it is intended to assist communities in prudently and soundly managing floodplain development and prevent additional damages to other property owners. The community is responsible for prohibiting encroachments, including fill, new construction, and substantial improvements, within the floodway unless it has been demonstrated through hydrologic and hydraulic analyses that the proposed encroachment will not increase flood levels within the community. In areas that fall within the 1-percent-annual-chance floodplain, but are outside the floodway (termed the "floodway fringe"), development will, by definition, cause no more than a 1.0-foot increase in the 1-percent-annual-chance water-surface elevation. Floodplain management through the use of the floodway concept is effective because it allows communities to develop in floodprone areas if they so choose, but limits the future increases of flood hazards to no more than 1.0 foot.

81. What procedures are available for changing or correcting a Flood Insurance Rate Map?
FEMA has established administrative procedures for changing effective FIRMs and FIS reports based on new or revised scientific or technical data. A physical change to the affected FIRM panels and portions of the FIS report is referred to as a "Physical Map Revision," or "PMR." Changes can also be made by a Letter of Map Change (LOMC). The three LOMC categories are Letter of Map Amendment (LOMA), Letter of Map Revision based on Fill (LOMR-F), and Letter of Map Revision (LOMR). These LOMC categories are discussed in more detail later.

82. What comprises technical or scientific data?
In general, the scientific or technical data needed to effect a map amendment or revision include certified topographic data and/or hydrologic and hydraulic analyses to support the request for amendment or revision.

83. What is a Physical Map Revision (PMR)?
A PMR is an official republication of a community's NFIP map to effect changes to base (1-percent-annual-chance) flood elevations, floodplain boundary delineations, regulatory floodways, and planimetric features. These changes typically occur as a result of structural works or improvements, annexations resulting in additional flood hazard areas, or correction to base flood elevations or SFHAs.

The community's chief executive officer (CEO) must submit scientific and technical data to FEMA to support the request for a PMR. The data will be analyzed, and the map will be revised if warranted. The community is provided with copies of the revised information and is afforded a review period. When base flood elevations are changed, a 90-day appeal period is provided. A 6-month period for formal approval of the revised map(s) is also provided.

84. What is a Letter of Map Revision Based on Fill (LOMR-F)?
A LOMR-F is an official revision by letter to an effective NFIP map. A LOMR-F states FEMA's determination concerning whether a structure or parcel has been elevated on fill above the base flood elevation and is, therefore, excluded from the SFHA.

85. What is a Letter of Map Amendment (LOMA)?
A LOMA is an official revision by letter to an effective NFIP map. A LOMA results from an administrative procedure that involves the review of scientific or technical data submitted by the owner or lessee of property who believes the property has incorrectly been included in a designated SFHA. A LOMA amends the currently effective FEMA map and establishes that a specific property is not located in an SFHA.

86. What is a Letter of Map Revision (LOMR)?
A LOMR is an official revision to the currently effective FEMA map. It is used to change flood zones, floodplain and floodway delineations, flood elevations, and planimetric features. All requests for LOMRs should be made to FEMA through the chief executive officer of the community, since it is the community that must adopt any changes and revisions to the map. If the request for a LOMR is not submitted through the chief executive officer of the community, evidence must be submitted that the community has been notified of the request.

87. What is a conditional map revision?
NFIP maps must be based on existing, rather than proposed, conditions. Because flood insurance is a financial protection mechanism for real-property owners and lending institutions against existing hazards, flood insurance ratings must be made accordingly. However, communities, developers, and property owners often undertake projects that may alter or mitigate flood hazards and would like FEMA's comment before constructing them. A Conditional Letter of Map Revision (CLOMR) is FEMA's formal review and comment as to whether a proposed project complies with the minimum NFIP floodplain management criteria. If it is determined that it does, the CLOMR also describes any eventual revisions that will be made to the NFIP maps upon completion of the project.

While obtaining a CLOMR may be desired, obtaining conditional approval is not automatically required by NFIP regulations for all projects in the floodway or 1-percent annual chance floodplain. A CLOMR is required only for those projects that will result in a 1-percent annual chance water surface elevation increase of greater than 1.00 foot for streams with BFEs specified, but no floodway designated, or any 1-percent annual chance water surface elevation increase for proposed construction within a regulatory floodway. The technical data needed to support a CLOMR request generally involve detailed hydrologic and hydraulic analyses and are very similar to the data needed for a LOMR request.

In addition to the situations described above, property owners and developers who intend to place structures in the 1-percent annual chance floodplain may need to demonstrate to the lending institutions and local officials before construction that proposed structures will be above the base flood elevation. If the project involves only the elevation of structures on natural high ground, they can request a Conditional Letter of Map Amendment (CLOMA) from FEMA. If the elevation of structures on earthen fill is the sole component of the project (i.e., there is no associated channelization, culvert construction, etc., that would alter flood elevations) and there is no fill placed in the regulatory floodway, they can request from FEMA a CLOMR based on fill or a CLOMR-F. Requests for CLOMAs and CLOMRS should be made by the community and addressed to the Mitigation Division Director at the appropriate FEMA Regional Office. The addresses of all FEMA Regional Offices are provided in the back of this booklet. Until a LOMR is issued, this property remains in the floodplain and is subject to the community floodplain management ordinance and the mandatory flood insurance purchase requirements.

88. Who should be contacted in FEMA to initiate a LOMA, LOMR, or Physical Map Revision?
Requests for conditional and final map revisions should be sent to the appropriate FEMA LOMA Depot. Any questions regarding LOMA/LOMR should be directed to one of FEMA's Flood Map Specialists. Contact information is provided in the "FEMA LOMA Depots" section at the back of this booklet.

89. How long does it take to obtain a LOMA, LOMR, or physical map revision?
For single-building or single-lot determinations that do not involve changes to base flood elevations or floodways, a LOMA or LOMR-F generally can be issued within 4 weeks. LOMAs and LOMRs involving multiple lots or multiple buildings require up to 8 weeks to process. Times are specified from the date of receipt of all technical, scientific, or legal documentation. LOMRs involving decreases in base flood elevations (BFEs) or floodways take approximately 90 days for processing. If changes in flooding conditions are extensive or if BFEs increase, a physical map revision will be required, which will take 12 months or longer.

90. If a LOMA, LOMR-F, or LOMR is issued by FEMA, will a lending institution automatically waive the flood insurance requirement?
Although FEMA may issue a LOMA, it is the lending institution's prerogative to require flood insurance as a condition of its own beyond the provisions of the Flood Disaster Protection Act of 1973 and the National Flood Insurance Reform Act of 1994, before granting a loan or mortgage. Those seeking a LOMA should first confer with the affected lending institution to determine whether the institution will waive the requirement for flood insurance if a LOMA is issued. If it will, the policyholder may cancel flood insurance coverage and obtain a premium refund. If not, amending the NFIP map to remove the structure from the SFHA will generally lower the flood insurance premium.

91. If a LOMA, LOMR-F, or LOMR is granted and the lender waives the requirement for flood insurance, how can a flood insurance policy be cancelled?
To effect a cancellation of a flood insurance policy, the policyholder must supply a copy of the LOMA, LOMR-F, or LOMR and a waiver for the flood insurance purchase requirement from the lending institution to the insurance agent or broker who services the policy. A completed cancellation form with the LOMA, LOMR-F, or LOMR and the waiver must be submitted by the agent to the NFIP or the appropriate WYO company. When a LOMA, LOMR-F, or LOMR is issued and cancellation requested, the policyholder may be eligible for a refund of the premium paid for the current policy year only if no claim is pending and no claim has been paid during the current policy year.

92. Why is the burden of proof on the person requesting a map change?
FEMA and its Federal and private-sector contractors exercise great care to ensure that analytical methods employed in FISs are scientifically and technically correct, the engineering practices followed meet professional standards, and the results of the FIS are accurate. In making amendments and revisions to NFIP maps and reports, FEMA must adhere to the same engineering standards applied in preparing the effective maps and reports. Therefore, when requesting changes to NFIP maps, community officials and property owners are required to submit adequate supporting data. FEMA would have no justification for changing a flood hazard determination without sufficient evidence that the change is appropriate.

93. Are fees assessed for map change requests submitted by community officials, developers, and property owners?
To minimize the financial burden on the policyholders while maintaining the NFIP as self-sustaining, FEMA implemented procedures to recover costs associated with reviewing and processing requests for conditional and final map amendments and map revisions. The fee schedule for these requests is published in the Federal Register and applies to all types of requests except those that are specifically exempted in Section 72.5(c) of the NFIP Regulations. Community officials and other individuals who have questions regarding the required review and processing fees should contact the appropriate FEMA Regional Office as listed at the back of this booklet.

94. What is the purpose of the application/ certification forms that are required for map change requests?
FEMA implemented the use of forms for requesting revisions or amend-ments to NFIP maps to provide a step-by-step process for requesters to follow. The forms are comprehensive; therefore, requesters are reasonably assured of preparing a complete request that includes all the necessary support data without having to go through an iterative process of providing additional information in a piecemeal fashion. Experience has shown piecemeal submissions to be time-consuming and expensive. Also, because use of the forms assures the requesters' submissions are complete and more logically structured, FEMA can complete its review in a shorter time frame. While completing the forms may appear to be burdensome, FEMA believes it is prudent to do so because of the advantages that result for the requester.

95. How can someone obtain copies of the technical data used in preparing the published NFIP maps?
Technical supporting data may be obtained by contacting a FEMA Flood Map Specialist listed the "NFIP Program Information" section at the back of this booklet. The letter should give the name of the community for which the data are sought, provide specific information as to the portion of the community and type of data needed, and give the requester's name and telephone number. Before the request is serviced, a representative will call to discuss the request. If a charge is necessary for the service, the extent of the service and the costs will be discussed during the call.