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USEFUL INFORMATION IN DETERMINING BFE IN AN UNNUMBERED ZONE A

Requirements for Obtaining BFE Data

44 CFR 60.3 (b) (4)

Obtain, review, and reasonably utilize any base flood elevation and floodway data available from a Federal, State, or other source…

Use of Draft or Preliminary Flood Insurance Study Data

• The data from a draft or preliminary flood insurance study constitutes “available data” under Subparagraph 60.3 (b) (4).

• Communities are given discretion concerning the use of draft or preliminary only if the data is currently part of a valid appeal concerning the accuracy of the data.

Requirements for Obtaining BFE Data

44 CFR 60.3 (b) (3)

Require that all new subdivision proposals and other proposed development (including proposals for manufactured home parks and subdivisions) greater than 50 lots or 5 acres, whichever is the lesser, include within such proposals base flood information data…

Use of Draft or Preliminary Flood Insurance Study Data

• The data from a draft or preliminary flood insurance study constitutes “available data” under Subparagraph 60.3 (b) (4).

• Communities are given discretion concerning the use of draft or preliminary only if the data is currently part of a valid appeal concerning the accuracy of the data.

Requirements for Obtaining BFE Data

44 CFR 60.3 (b) (3)

Require that all new subdivision proposals and other proposed development (including proposals for manufactured home parks and subdivisions) greater than 50 lots or 5 acres, whichever is the lesser, include within such proposals base flood information data…

FEMA publication Managing Floodplain Development in Approximate Zone A Areas (FEMA 265) is useful for engineers.

Obtaining Existing Base (100-Year) Flood Elevations

• Watershed Concepts - FEMA’s Contractor for the Regional Mapping Center

• U.S. Army Corps of Engineers

• U.S. Department of the Interior, Geological Survey

• U.S. Department of Agriculture, Natural Resources Conservation Service

• New Jersey Department of Transportation

• New Jersey Department of Environmental Protection

• Whichever engineering firm originally studied your community.

• If you need help determining the BFE, check with your community’s planning, engineering, or permit office.

• DOCUMENTATION: Whatever method you choose to use in determining the flood elevation for an unnumbered A Zone, always document where the determination came from.

•

BFE Development

Zone A---The area that would be inundated by the base flood for which no BFEs have been determined

Zone A Flooding: Various methods available:

• Existing high water profiles, aerial photographs of historic floods

• Develop the BFE in-house using USGS quads, QUICK-2, National Flood Frequency (NFF), and other programs, from determined cross-sections, drainage area, precipitation, etc.

• Calculations submitted by registered professional engineers

• Federal, State or local agencies may have conducted detailed analyses not incorporated into the effective NFIP maps. The results of these studies may be used as “best available data” for LOMC determinations in Zone A flooding.

What data can be used to determine BFEs?

• Any information that represents the best available data

• Any information that is known to be scientifically or technically correct (including preliminary FIS)

Sources that provide existing BFE information

• FEMA

• Federal, State, or Local Agencies

• Corps of Engineers, USGS, NRCS, Flood Control Districts, etc.

Developing a BFE

• Simplified Methods

•Contour interpolation •Data Extrapolation

• Detailed Methods

•Hand Calculations •Quick-2 •Hydraulic Models

Contour Interpolation

• Reduce or enlarge the topographic map of the site to the scale of the FIRM

• Superimpose the Zone A floodplain boundary onto the topographic map

• Determine if floodplain boundary conforms with contour lines within acceptable limits

• Elevations of the left and right overbanks must be within one half the contour

interval of the map

• If the method is reasonably accurate, determine the BFE

Data Extrapolation

Applicability

• Site must be within 500 feet of the detailed study area

• Site must have floodplain characteristics similar to the detailed study area

• Site must have no hydraulic structures

• Determine the location of the site on the flood profile for the detailed study area

• Extrapolate the last segment of the flood profile that has a constant slope to the

location of the site

• Determine the BFE from the extrapolated profile

DOCUMENTATION: Whatever method you choose to use in determining the flood elevation for an unnumbered A Zone, always document where the determination came from.

INFORMATION FOR LOMCs (Letter of Map Changes):

To be eligible for a Letter of Map Amendment (LOMA) from FEMA, you must be able to prove that the water elevation of the 100-year flood (or “base flood elevation”) is lower than the ground elevation at the lowest exterior point around your foundation.

Why won't the lender take my surveyor's word?

The Flood Insurance Rate Maps (FIRMs) and Flood Hazard Boundary Maps (FHBM) portray the Special Flood Hazard Area (SFHA), or what is more commonly known as the gray shaded area, within which the purchase of flood insurance is required as a condition for granting a mortgage from a federally-backed or federally-regulated lending institution. The lender or insurance agent must use the boundaries of the SFHAs shown on the Flood Insurance Rate Maps to determine if mandatory flood insurance applies. The area between the flooding source and the flood hazard boundary is commonly shaded gray. Thus, even though a site survey or an elevation certificate indicates the homesite is above the Base Flood Elevation (BFE) and is technically outside the floodplain, if the homesite is within the gray shaded area (the SFHA) on the map, the bank will say flood insurance is required.

Are the flood maps wrong?

The general lack of detailed topographic mapping throughout this nation means that the floodplain boundaries in most communities cannot be accurately mapped. Since, FEMA (Federal Emergency Management Agency) cannot afford to field check all floodplain boundaries, some areas of high ground are shown as floodplain, and some low areas are not.

What is FEMA going to do about flood maps being wrong ?

In short, nothing. However, FEMA created the Letter of Map Amendment and Revision (LOMA/R) process to correct or change flood maps [FIRMs and FHBMs] to reflect actual ground surveys or better topographic mapping. Letters are issued by FEMA officially removing lots or portions of lots (by legal description) from the SFHA or changing the boundaries of the SFHA. These are dated and sent to the homeowner applicant and are also filed with the municipality or county within which the property is located. The building site is removed from flood zone AE, AI-30, A, etc and placed in flood zone B, C, or X, which are not part of the SFHA [Special Flood Hazard Area].

When a LOMA/R is issued removing a building site from the SFHA, the mandatory flood insurance purchase requirement is lifted. However, the lender always has the option of requiring flood insurance anyway. For example, the homesite might be just a few inches above BFE, so the lender feels that there is still a threat of flood damage to their "secured property". Once the flood zone has been changed to B, C, or X, the building qualifies for a PREFFERRED RISK POLICY, the least expensive flood insurance available.

Letter of Map Amendment (LOMA): This is used to revise the SFHA boundary based on detailed elevation surveying and/or topographic mapping of the site. If the homesite and the lowest floor of the building (including basement or garage) is the BFE, FEMA can the map to remove the homesite and other land area from the SFHA. (The map will not actually be physically changed or revised, but the structure or homesite will be certified as being outside the SFHA)

Letter of Map Revision, based on fill (LOMR-F): When FILL dirt is placed on property to raise the building site above the BFE FEMA can remove the raised area from the boundaries of the SFHA, thus revising the FIRM. This is a man-made change to the floodplain.

How do I get a LOMA or LOMR-F?

A homeowner may apply for a LOMA or LOMR-F. However, a Site Plan & Boundary Survey and Elevation Information or Elevation Certificate must accompany each application. These must be prepared, sealed and certified by a Professional Land Surveyor. The applicant is responsible for paying for this survey information.

To be eligible for a Letter of Map Amendment (LOMA) from FEMA, you must be able to prove that the water elevation of the 100-year flood (or “base flood elevation”) is lower than the ground elevation at the lowest exterior point around your foundation. Part 70 of the NFIP Regulations requires that the lowest ground touching the structure be equal to or higher than the BFE

How long does it take to get FEMA to approve a LOMA or LOMR-F?

It normally takes 6-12 weeks from the time an application is received until a letter of determination is issued. Applications are processed on a first come, first served basis.

What if there is no flood elevation on the flood map?

If the property is in Flood Zone A, without a letter or number after the "A", the flood zone is "approximate". [FEMA calls it an "unnumbered A Zone"] No Base Flood Elevation (BFE) has been determined for the area. However, FEMA can only approve a LOMA/R if a BFE has been established using standard engineering methodology or using the simplified method.

Sometimes another government agency has done a flood study and determined flood elevations, or perhaps the lot is in a fairly recent subdivision for which flood elevations were determined as part of the land development process. Check with your local building inspector or code enforcement officer. However, it is unlikely in this area to find such information.

If there is no existing flood study, one will have to be developed in order to process a LOMA/R, either by the simplified methodology or by a watershed study, which is very costly.

LOMAs or LOMR-Fs in Flood Zone A are usually more complicated. Be prepared!

LAG - Lowest Adjacent Grade: The elevation of the lowest ground touching the structure’s foundation

For LOMC submittals removal of a structure from SFHA is based on the LAG, not the finished floor.

Obtaining FIS Back-up Data

• Must request in writing -- Approximately 2 to 4 weeks to process requests

• Typically costs $100-$200

• Can fax request to (703) 751-7391

•

• A Flood Insurance Study (FIS) is a book that contains information regarding flooding in a community and is developed in conjunction with the FIRM and FHBM

• The FIS contains flood profiles, floodway data tables, summaries of elevations as well as a narrative of the flood history of a community and discusses the engineering methods used to develop the FIRMS

• If the flooding is conveyed by the street, provide the highest top of curb or crown of street elevation along the property line and add the depth of flooding to determine the BFE .

• If the entire property is inundated by the SFHA and the flow is not conveyed by the street, add the depth of flooding to the average lot elevation

• If the property is partially inundated by the SFHA and the street does not convey the flow, add the depth of flooding to the lowest lot elevation

• Along with the information required above, sufficient certified topographic information, including flow paths, to show that the structure is located on high ground relative to the depth of flooding is required

FEMA may calculate the BFE for A-Zone properties

• For single lot less than 5 acres

• Will require additional survey data (river cross-section)

INFORMATION FOR ELEVATION CERTIFICATE (EC):

Elevation Certificate (EC)

• Administrative tool of the NFIP

• Used only to certify building elevations

• Required to properly rate post-FIRM buildings

• Provides a way for communities to record elevation information & document compliance

• Can be used to support a LOMA or LOMR-F request

• Does not provide a waiver of insurance purchase requirements

• Only a LOMA or LOMR-F can remove the Federal mandate for insurance requirement

Highlights of Section D

• This section must be certified by a surveyor, engineer, or architect

• Section needs to contain a signature

• Stamp/Seal is not required by FEMA but check with local and state regulations

• Comment Section

o Can be used to list the Lowest Lot Elevation, Top of Curb elevation for Zone A and AO cases

o Further clarification of how the BFE was determined

When do I have to do a conversion from NGVD to NAVD?

Answer) If there is anything on the Elevation Certificate (EC) to indicate that a different datum has been used for the Base Flood Elevation (BFE) and the Lowest Floor Elevation (LFE), the data conversion process must be used to ensure that all numbers reflect the same datum. The Underwriting Bulletin dated July 27, 2009, states that when an existing EC provides the building elevations referenced to NGVD 29, and the BFEs on the Flood Insurance Rate

Map (FIRM) are referenced to NAVD 88, the NGVD 29 elevations must be converted to NAVD 88.



If I have dual foundations, which have not been specifically addressed, how do I rate the building?

Answer) If part of the building is slab-on-grade and part is elevated by posts, piers, piles, or foundation walls, use the lowest part of the building in determining the correct building description. This means that if the slab-on-grade part of the building is lower than the elevated portion of the building, you must describe the building as a non-elevated building.

If there is a shed outside of the footprint of the main structure, it will not be considered an enclosure or an obstruction. The shed will be considered an appurtenant structure, and contents coverage will be available if the shed meets the definition of a building (including being tied down or permanently affixed to the site.) Note: Except for a detached garage, appurtenant structures must have building coverage purchased separately.

Effective October 1, 2011, an EC will be required to obtain flood insurance for all buildings in unnumbered A, AO, and AH zones.

When there is no BFE, the EC must provide the distance from the reference floor to “highest adjacent grade.” This is the highest natural grade, immediately adjacent to the building, prior to construction. If the structure is slab-on-grade on a fill pad, the highest adjacent grade is beneath the fill. This distance can be determined from the grading and fill information filed with the building plans and/or by using a hand soil bore to obtain a core of soil from alongside the structure. A practical alternative is to locate the highest natural grade adjoining the base of the fill pad out away from the house. The distance from the top of the core to the original soil level can be measured and placed on the EC. Highest grade is not the top of the fill pad.

Flood insurance rates are based on actuarial risk. Rates are lower when a BFE has been established or estimated in an “A” Zone. When no BFE is estimated or available, the rates are based on distance above highest adjacent grade. The higher above grade, the lower the rates. Houses raised on fill will be inadvertently penalized if the top of the fill pad is used as highest grade, rather than the original natural grade.

If you need help determining the BFE, check with your community’s planning, engineering, or permit office.

LIABILITY ISSUES

Professional Liability

Bodin v. Gill, 117 S.E.2d 325 (Ga., 1960) in which the court stated the broad rule of law which applies to

not only architects and engineers but other professional services. The court stated that “The law imposes

upon persons performing architectural, engineering, and other professional and skilled services the

obligation to exercise a reasonable degree of care, skill, and ability, which generally is taken and

considered to be such a degree of care and skill as, under similar conditions and like surrounding

circumstances, is ordinarily employed by their respective professions.” However, the standards of care and

the proof required differ. Design professionals are held to a standard of care consistent with the minimum

standard of care in their profession and expert testimony must usually be used to establish this standard of

care. See Lochrane Eng v. Willingham Realgrowth, 552 So.2d 228 (Fla., 1989) This may or may not be

true for others who perform services but lack professional status.

Courts have applied the term “design professional” primarily to architects, engineers, landscape architects,

and surveyors.



Liability Based on Negligence

A design professional may also be held liable because he or she has been “negligent”. As

common law, all members of society (not just design professionals) must act reasonably

so as not to injure other members of society. If they do not act reasonably and injuries

result, they may under certain circumstances be sued for negligence.

Negligence in design or failure to provide contracted services can be based on incomplete

design specifications or services as well as complete but erroneous ones. It is not

sufficient for a design professional to perform as well as he or she could. The design

professional must have done what the reasonable design professional of ordinary prudence in the profession would have done. The standard is usually one of the design community as a whole, but a higher standard may be applied where the design professional has made special representations, where statutes or ordinances establish a higher standard than is customarily used, or in cases in which a particularly great or grave risk of harm is involved.

See, e.g., Trusky v. Holoway, 14-04-00196-CV (Texas, 2205) in which the court held a surveyor liable

on negligence and Deceptive Trade Practices Act causes of action to a landowner for failing to tell the

landowner that a property was in a floodway. He did indicate that the property was in a floodplain.

Regulations. An architect or engineer is, in general, responsible for acquainting himself

or herself with all applicable regulations. This means that the architect or engineer should

investigate not only local zoning, subdivision control and building codes but applicable

state and federal regulations (e.g., the Section 404 permitting program). Negligence may

“arise from breach either of a common law duty or one imposed by statute or regulation

since the conduct of a “reasonable man” may be prescribed by legislative enactment.”36

In general, violation of a statute or ordinance creates, at a minimum, a presumption of

negligence or evidence of negligence.

Government Liability

Although design professionals employed by governments are not liable as individuals,

their government units (local, state, federal) may be. Governments may be sued for

negligence if public employees negligently design or construct a structure with resulting

injury to a member of the public. They may be liable if their employees provide

inadequate flash flood warnings to members of the public on public lands. They may

be sued for negligence, trespass, nuisance or under another common law theory or for a

taking of private property without payment of compensation under a state or the federal Constitution if they increase flood or erosion damage on nongovernmental lands.136

Governments are particularly vulnerable to suits for negligence based upon “ministerial”

acts of employees such as improper maintenance of a drainage ditch. In general,

governments are not liable for “discretionary” acts such selecting the flood passage

design capacity for a bridge.

STATE OF VERMONT – A ZONE (UNNUMBERED) CROSS SECTION SURVEY EXAMPLE -- Surveying for a LOMA in “Zone A”



Regions labeled as “Zone A” on your floodplain map indicate those areas where FEMA has designated the approximate floodplain, but has not done the detailed river studies necessary to establish a base flood elevation.

If your parcel is less than 5 acres in size, FEMA will calculate the base flood elevation for you IF you provide the appropriate survey information with your LOMA application:

- The surveyor must establish a cross-section of the stream. This cross-section should begin at the upstream edge of your structure, and should extend perpendicular to the stream. The cross-section should extend on the opposite bank of the stream to the point where the relative ground elevation on the opposite bank equals or exceeds the ground elevation of your structure.

- Several survey points should be established along this cross-section. A survey point should be included at every point where there is a significant break in slope or change in topography along the cross-section. Elevation and distance along the cross-section should be measured for each survey point. Elevation can be measured using an “assumed datum”, where the surveyor establishes an arbitrary elevation at a nearby landmark and records relative elevations compared to that point. Distance along the cross-section can be made starting from the corner of your structure.

- All distance and elevation measurements should be recorded in a table. The surveyor should include a scaled diagram of the cross-section that includes each of the survey points (see “cross-section view” ). An “overhead view” of the cross-section (including the survey points) that shows the home in relation to the stream should also be included.

- Include all other information relevant to the survey. You should include several photos of the banks on either side of the stream. Knowing the type of ground cover nearby is necessary for FEMA to model the base flood elevation.

- Your LOMA application should also include the ground elevation at the lowest point around your foundation (also called the “lowest adjacent grade”), using the assumed datum.

This survey information should allow FEMA to calculate a base flood elevation for your site, and compare that information to the lowest adjacent grade. PLEASE NOTE: the investment of time and money needed to obtain this survey information does not guarantee that the outcome will be favorable, and there is always the possibility that the base flood elevation will be higher than your lowest adjacent grade.

If you have questions regarding Letters of Map Amendment from FEMA please visit the FEMA Map Assistance Center (), or contact a FEMA Map Specialist at “FEMAMapSpecialist@” or 1-877-FEMA-MAP (1-877-336-2627).

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