Federal Emergency Management Agency 
Washington, 20472 
MEMORANDUM FOR: Regional Directors 
FROM: 
SUBJECT: 
Procedure Memorandum No. 36-Profile Baselines on 
Digital Flood Insurance Rate Maps with 
Orthophoto Bases 


Background: Since Guidelines and Specifications for Flood Hazard Mapping Partners 
was last updated, several studies performed by Indefinite Delivery Indefinite 
Quantity Contractors 


and Cooperating Technical Partners 


were brought 
to the attention of the Engineering and Mapping Integrated Program Team (IPT) as being 
processed without a streamline or profile baseline when orthophotos were used as the 
base. During the independent quality assurance reviews for these studies, it became 
apparent that it is necessary to at least show a profile baseline (that matches the 
streamlines shown on the effective FIRM) on all DFIRMs. The April 2003 version of the 
Guidelines does not specify that streamlines or profile baselines are required on 
that are developed using orthophoto bases; rather, the Guidelines states that the 
streamlines or profile baselines are optional, as indicated below. 


Appendix C, Subsection C.6.1.5 (Page C-37) of the Guidelines, entitled 
"Effective Floodplain 
to New Streamlines,"states the 
following: 

The process of fitting unrevised floodplain boundaries to new 
streamlines likely will result in changes in stream channel distances from 
the unrevised hydraulic model to the new FIRM. Theses changes shall 
be addressed by placing a note in the FIRM legend on a case-by-case 
basis.. 

(See Appendix 


of these Guidelines for examples of this 
note.) 
Appendix K, Subsection K.4.1.1 (Page K-43) of the Guidelines, entitled "Base 
Map Types,"states the following: "The assigned Mapping Partner may show 
vectors that depict studied flooding sources on top of the orthophotos to clarify 
their locations." 
For Table 
Appendix L of the Guidelines, entitled "Guidance for 
Preparing Draft Digital Data and Database,"states the following on Page 
L-113: 



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This table is required for a detailed study when hydrologic and hydraulic 
models have been developed for reaches of streams. The results of the 
models are shown on the FIRM. The profile baseline and/or stream 
centerline may or may not be shown on the FIRM. 


For Table 
Appendix L of the Guidelines, entitled "Guidance for 
Preparing Draft Digital Data and DFIRM Database,"states the following on Page 
L-347: "Vector streams must always be shown with a vector base map. They 
may also be shown on raster base maps." 

Issue: 

Streamlines and profile baselines are linked to the hydraulic models developed for 

detailed-study reaches. Without these links, the relationship between the DFJRM, the 

Flood Profiles, and the Data Table will no longer exist. This will impact the 


affected communities' ability to use the DFIRM, Flood Profiles, and 


Data 
Table for accurate floodplain management and provide property owners accurate 
information. Therefore, developing a Base Flood Elevation 


that is accurate and 
usable for processing Conditional Letters of Map Amendment; Conditional Letters of 
Map Revision Based on Fill, Letters of Map Amendment; and Letters of Map Revision 
Based on Fill will be very difficult, if not impossible. Likewise, it will be very difficult, 
if not impossible, to determine whether revised BFEs for Conditional Letters of Map 
Revision and Letters of Map Revision tie into effective BFEs at the upstream and 
downstream ends of the revised reach within the maximum allowable tolerance of 0.5 
foot, and to determine whether increases over 1.0 foot between BFEs and the regulatory 


elevations occur. 

Action Procedure: 

This memorandum revises several sections of the April 2003 version of the Guidelines 
and sets forth a requirement that a profile baseline 


that matches the 


baseline used in the effective or new study must be shown on all 

DFIRMs. The profile baseline can be included in the 


table as a line with a 
WATER-TYP of PROFILE BASELINE, or can be added to the 


table. 

All mapping partners, including 


and CTPs, that are tasked with issuing the 
Preliminary are to produce Preliminary DFIRMs that meet FEMA 
specifications, including the changes described in this memorandum. If the 
CTPs cannot meet these specifications, FEMA Regional Office staff should establish a 
clear plan for how the affected will be brought into compliance with FEMA 
specifications before the DFIRMs become effective and how that work will be funded. 
The FEMA Regional Office staff should coordinate the plan with the respective Project 
Engineer from the Hazard Section at FEMA Headquarters as soon as any 
temporary deviations from the specifications are identified. 

cc: See Distribution List 
or 

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Distribution List (electronic distribution only) 

Office of the Mitigation Division Director 

Risk Assessment Branch 

Risk Identification Branch 

Flood Insurance and Mitigation Divisions in FEMA Regional Offices 

Office of Legislative Affairs 

Office of General Counsel 

National Service Provider 

Systems Engineering and Technical Assistance Contractor 

Map Service Center