FEMA Digital Flood Rate Insurance Maps (DFIRM), Minnesota
Go to Section:- Overview
- Data Quality
- Data Organization
- Coordinate System
- Attributes
- Distribution - Get Data
- Metadata Reference
Section 1: Overview
Originator:Federal Emergency Management Agency (FEMA)
Title:
FEMA Digital Flood Rate Insurance Maps (DFIRM), Minnesota
Abstract:
The Federal Emergency Managment Agency and the MNDNR produce Digital Flood Insurance Rate Maps (DFIRM) for selected counties in the state. These maps are often referred to as FEMA Floodplain maps.
A DFIRM is the offical digital map of a community on which FEMA has delineated the special flood hazard areas, i.e., the floodplain areas where flood insurance is required for loans and where communities will administer floodplain regulations. (Note: Communities may regulate additional flood prone areas that are not on the FIRM).
Here are some of the feature classes included in the MNDNR's publication of the DFIRM Dataset:
FEMA DFIRM Base Flood Elevations
The Base Flood Elevation (BFE) table is required for any digital data where BFE lines will be shown on the corresponding Flood Insurance Rate Map (FIRM). Normally, if there are any riverine AE zones, BFE lines are required. The BFE table contains information about the BFEs within a study area. A spatial file with locational information also corresponds with this data table. BFE lines indicate the rounded whole-foot water-surface elevation of the 1-percent-annual-chance flood. The spatial elements representing BFE features are lines extending from Special Flood Hazard Area (SFHA) boundary to SFHA boundary. The BFE lines will have no visible gaps or overshoots between the SFHA boundary and the end of the BFE line at the publication scale of the DFIRM. However, the ends of the BFE lines are not necessarily snapped precisely to the SFHA boundary. Each BFE is represented by a single line. While BFE lines are depicted as wavy lines on the hardcopy FIRM, they should be primarily straight lines in the spatial data, although they may bend consistent with procedures described in Volume 1 of these Guidelines.
FEMA DFIRM Flood Hazard Zones
FEMA flood hazard delineations are used by FEMA to designate the SFHA and for insurance rating purposes. These data are the flood hazard areas that are or will be depicted on the FIRM.
FEMA DFIRM Panel Scheme Polygons
This layer contains information about the FIRM panel areas. The spatial entities representing FIRM panels are polygons. The polygon for the FIRM panel corresponds to the panel neatlines. As a result, the panels are generally rectangular. In situations where a portion of a panel lies outside of the jurisdiction being mapped, the user must refer to the S_POL_AR table to determine the portion of the panel area where the DFIRM database shows the effective flood hazard data for the mapped jurisdiction.
FEMA DFIRM Cross Sections
FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the FIRM. Normally any FIRM that has associated flood profiles has cross sections. The corresponding attribute table contains information about cross section lines. A spatial file with locational information also corresponds with this data table. These lines represent the locations of channel surveys performed for input into the hydraulic model used to calculate flood elevations. These locations are also shown on the Flood Profiles in the Flood Insurance Study (FIS) report and can be used to cross reference the Flood Profiles to the planimetric depiction of the flood hazards. All cross sections for which a spatial location is available should be included in this table. The spatial elements representing cross sections are lines generally extending from outside the floodplain, across the entire floodplain and out the other side. Each cross section should be represented by a single line feature without the hexagons shown on each end on the hardcopy map. The location and shape of the lines should depict as accurately as possible the position of the cross section used. This is a modified Standard DFIRM Database table that includes Standard DFIRM Database items and Enhanced Database items. All items after SOURCE_CIT are Enhanced. The Enhanced DFIRM Database must contain all modeled cross sections, whether they are printed on the FIRM or not.
Extensive information regarding the source data can be found in these two documents:
FEMA DFIRM Doc Appendix L Part A.pdf
FEMA DFIRM Doc Appendix L Part B.pdf
Purpose:
The FIRM is the basis for floodplain management, mitigation, and insurance activities for the National Flood Insurance Program (NFIP). Insurance applications include enforcement of the mandatory purchase requirement of the Flood Disaster Protection Act, which "... requires the purchase of flood insurance by property owners who are being assisted by Federal programs or by Federally supervised, regulated or insured agencies or institutions in the aquisition or improvement of land facilities located or to be located in indentified areas having special flood hazards," Section 2 (b) (4) of the Flood Disaster Protection Act of 1973. In addition to the identification of Special Flood Hazard Areas (SFHAs), the risk zones shown on the FIRMs are the basis for the establishment of premium rates for flood coverage offered through the NFIP. The DFIRM Database presents the flood risk information depicted on the FIRM in a digital format suitable for use in electronic mapping applications. The DFIRM database is a subset of the Digital FIS database that serves to archive the information collected during the FIS.
Time Period of Content Date:
09/07/2023
Currentness Reference:
FEMA DFIRM CD-ROM Release Date for each county, 2006-Present. Time Period of Content date indicates the date which the user can be confident of accuracy and completeness of the dataset, through our direct work with FEMA.
Progress:
In work
Maintenance and Update Frequency:
As needed
Spatial Extent of Data:
Bounding Coordinates:
-97.23
-89.53
49.37
43.5
Place Keywords:
Minnesota, MN
Theme Keywords:
inlandWaters, FEMA, flood hazard zone, DFIRM database, DFIRM Special Flood Hazard Area, Digital Flood Insurance Rate Map, Flooding Base, Flood Elevation, SFHA Flood Insurance Rate Map, Floodway
Theme Keyword Thesaurus:
ISO 19115 Category
Access Constraints:
None
Use Constraints:
Use of the data are constrained by the DNR GIS Data License Agreement. See the Distribution Liability section below for a link. In addition, acknowledgment of FEMA would be appreciated in products derived from these data.
No warranty expressed or implied is made by FEMA regarding the utility of the data on any other system nor shall the act of distribution constitute any such warranty. For the purposes of the National Flood Insurance Program (NFIP), changes to the flood risk information published by FEMA may only be performed by FEMA and through the mechanisms established in the NFIP regulation (44 CFR Parts 59-78). These digital data are produced in conjunction with the hardcopy FIRMs and generally match the hardcopy map exactly. However the hardcopy flood maps and flood profiles are the authoritative documents for the NFIP. Acknowledgement of FEMA would be appreciated in products derived from these data.
Contact Person Information:
FEMA Map Service Center,
Federal Emergency Management Agency
500 C Street S.W.
Washington D.C.,
DC
20472
Phone: 1-800-358-9616
Email: MSCservices@riskmapcds.com
Associated Data Sets:
Section 2: Data Quality
Attribute Accuracy:
Logical Consistency:
When FEMA revises an FIS, adjacent studies are checked to ensure agreement between flood elevations at the boundaries. Likewise, flood elevations at the confluence of streams studied independently are checked to ensure agreement at the confluence. The FIRM and the FIS are developed together and care is taken to ensure that the elevations and other features shown on the flood profiles in the FIS agree with the information shown on the FIRM. However, the elevations as shown on the FIRM are rounded whole-foot elevations. They must be shown so that a profile recreated from the elevations on the FIRM will match the FIS profiles within one half of one foot.
Completeness:
Complete for counties where DFIRM data has been released
Horizontal Positional Accuracy:
The DFIRM Database consists of countywide vector files and associated attributes produced in conjunction with the hardcopy FEMA FIRM. The published effective FIRM and DFIRM are issued as the official designation of the SFHAs. As such, they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines and specifications for Flood Map Production Coordination Contractors. Horizontal accuracy was tested by manual comparison of source graphics with hardcopy plots and a symbolized display on an interactive computer graphic system. Independent quality control testing of FEMA's DFIRM database was also performed.
Vertical Positional Accuracy:
The DFIRM Database consists of countywide vector files and associated attributes produced in conjunction with the hardcopy FEMA FIRM. The published effective FIRM and DFIRM are issued as the official designation of the SFHAs. As such, they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines and specifications for Flood Map Production Coordination Contractors. Vertical accuracy was tested by manual comparison of source graphics with hardcopy plots and a symbolized display on an interactive computer graphic system. Independent quality control testing of FEMA's DFIRM database was also performed.
Lineage:
Attribute Lineage: Data was pulled from original FEMA DFIRM cd-roms. The DNR County abbreviation was added to the attribute table. Data were then exported as a shapefile attribute table (dBase format), and appended together in a single Esri File Geodatabase.
Cartographic Lineage: Created through a combination of field survey, air photo interpretation, and adjustment to orthophotography.
Section 3: Spatial Data Organization (not used in this metadata)
Section 4: Coordinate System
Horizontal Coordinate Scheme:
Universal Transverse Mercator
UTM Zone Number:
15
Horizontal Datum:
NAD83
Horizontal Units:
meters
Vertical Datum:
Vertical Units:
Depth Datum:
Depth Units:
Section 5: Attributes
Overview:
Data Elements for Attribute Table base_flood_elevations:
BFE_LN_ID: Primary key for table lookup. Assigned by table creator.
ELEV: Base Flood Elevation. The rounded, whole foot elevation of the 1-percent-annual-chance flood. This is the value of the BFE that is printed next to the BFE line on the FIRM.
LEN_UNIT: Length Unit Lookup Identification. A code that provides a link to a valid unit of length measurement from the D_Length_Units table. This unit indicates the measurement system used for the BFEs. Normally this would be feet.
SOURCE_CIT: Source Citation. Abbreviation used in the metadata file when describing the source information for the S_BFE table.
V_DATUM: Vertical Datum Lookup Identification. A code that provides a link to a valid vertical datum from the D_V_Datum table. The vertical datum indicates the reference surface from which the flood elevations are measured. Normally this would be North American Vertical Datum of 1988 for new studies.
CTY_ABBR: DNR County Name Abbreviation (four letter)
Data Elements for Attribute Table flood_hazard_zones:
FLD_AR_ID: Primary key for table lookup. Assigned by table creator.
FLD_ZONE: This is a flood zone designation. These zones are used by FEMA to designate the SFHAs and for insurance rating purposes. Acceptable values for this field are listed in the D_Zone table.
ZONE_SUBTY: Flood Zone Subtype. This field captures additional information about the flood zones not related to insurance rating purposes. For example, Zone X could have "AREA WITH REDUCED FLOOD HAZARD DUE TO ACCREDITED LEVEE SYSTEM" or "0.2-PERCENTANNUAL CHANCE FLOOD HAZARD" as a subtype. Types of floodways are also stored in this field. Floodways are designated by FEMA and adopted by communities to provide an area that will remain free of development to moderate increases in flood heights due to encroachment on the floodplain. Normal floodways are specified as 'FLOODWAY.' Acceptable values for this field
are listed in the D_Zone_Subtype table.
SFHA_TF: Special Flood Hazard Area. If the area is within SFHA this field would be True. This field will be true for any area that is coded for any A or V zone flood areas. It should be false for any X or D zone flood areas. Enter 'T' for true or 'F' for false.
STATIC_BFE: Static Base Flood Elevation. For areas of constant Base Flood Elevation (BFE), the BFE value is shown beneath the zone label rather than on a BFE line. In this situation the same BFE applies to the entire polygon. This is normally occurs in lakes or coastal zones. This field is only populated where a static BFE is shown on the FIRM.
V_DATUM: Vertical Datum Lookup Identification. A code that provides a link to a valid vertical datum from the D_V_Datum table. The vertical datum indicates the reference surface from which the flood elevations are measured. Normally this would be North American Vertical Datum of 1988 for new studies. This field is only populated if the STATIC_BFE is populated.
DEPTH: Depth Value for Zone AO Areas. This is shown beneath the zone label on the FIRM. This field is only populated if a depth is shown on the FIRM.
LEN_UNIT: Length Unit Lookup Identification. A code that provides a link to a valid unit of length from the D_Length_Units table. This unit indicates the measurement system used for the BFEs and/or depths. Normally this would be feet. This field is only populated if the DEPTH or STATIC_BFE field is populated.
VELOCITY: Velocity Measurement. This is shown beneath the zone label on the FIRM for alluvial fan areas (certain Zone AO areas). This value represents the velocity of the flood flow in this area. This field is only populated when a velocity is shown on the FIRM.
AR_REVERT: If the area is Zone AR, this field would hold the zone that the area would revert to if the AR zone were removed. This field is only populated if the corresponding area is Zone AR. Acceptable values for this field are listed in the D_Zone table.
BFE_REVERT: If Zone is Zone AR, this field would hold the static base flood elevation for the reverted zone. This field is populated when Zone equals AR and the reverted zone has a static BFE.
DEP_REVERT: If Zone is Zone AR, this field would hold that flood depth for the reverted zone. This field is populated when Zone equals AR and the reverted zone has a depth assigned
SOURCE_CIT: Source Citation. Abbreviation used in the metadata file when describing the source information for the S_Fld_Haz_Ar table. Normally, the flood hazard area polygon will be divided to distinguish areas modified by the most recent revision from areas based on the effective FIRM prior to the most recent revision. Revisions and sources prior to the most recent revision will not be tracked for individual polygons in the flood hazard areas table in the standard database.
CTY_ABBR: DNR County Name Abbreviation (four letter)
Data Elements for Attribute Table dfirm_panel_scheme:
ST_FIPS: State FIPS. This is the two-digit code that corresponds to the State Federal Information Processing Standard (FIPS) code. This is a standard numbering system that is used by the Federal government. Defined in FIPS Pub 6-4. These two numbers correspond to the first two digits of the panel number.
PCOMM: Community or County Identification Number. This is the 3rd through the 6th digits of the panel number. For community based maps this corresponds to the Federal Emergency Management Agency (FEMA) Community Identification number. For countywide maps this is the county (or county equivalent) FIPS code with a 'C'.
PANEL: Panel Number. This is 7th through the 10th digits in the complete panel number. This is assigned by the scale of the map and the position within either the community or county. The panel number scheme is described in detail in Appendix K of these Guidelines.
SUFFIX: Map Suffix. This is the final digit in the complete panel number. This is a letter suffix at the end of the panel number.
FIRM_PAN: FIRM Panel Number. This is the complete FIRM panel number, which is made up of ST_FIPS, PCOMM, PANEL, and SUFFIX. This is the 11-digit FIRM panel number that is shown in the title block of the map.
PANEL_TYP: Panel Lookup Identification. A code that provides a link to the D_Panel_Typ table; this field will indicate if the maps are printed or not printed, community based, county wide, or an unmapped community.
EFF_DATE: Effective Date. This is the effective date of the current map revision. This field is not populated until the FIRM effective date is established and the Final FIRM is ready for hardcopy production by FEMA. Then it is required.
SCALE: Map Scale Lookup Identification. A code that provides a link to a value in the D_Scale table, it is the denominator of the scale of the FIRM.
PNP_REASON: Panel Not Printed Reason. If the FIRM panel is not printed, this is the reason. This could include 'All Zone X' or other reasons. See Appendix K for a listing of Panel Not Printed reasons that may be used. Only completed if the hardcopy panel is not printed by FEMA.
NW_LAT: Northwest Latitude. This is the latitude of the northwest corner of the FIRM panel neat line. This value is in degrees, minutes, seconds (DDD MM SS.SSS). Normally this corresponds to U.S. Geological Survey (USGS) 7.5' quadrangle maps using North American Datum of 1983 (NAD83), or even subdivisions thereof. However this value should reflect the actual latitude if non-standard panel sizes are used.
NW_LONG: Northwest Longitude. This is the longitude of the northwest corner of the FIRM panel. This value is in degrees, minutes, seconds (DDD MM SS.SSS). Normally this corresponds to USGS 7.5' quadrangle maps using NAD83, or even subdivisions thereof. However this value should reflect the actual longitude if non-standard panel sizes are used.
SE_LAT: Southeast Latitude. This is the latitude of the southeast corner of the FIRM panel. This value is in degrees, minutes, seconds (DDD MM SS.SSS). Normally this corresponds to USGS 7.5' quadrangle maps using NAD83, or even subdivisions thereof. However, this value should reflect the actual latitude if non-standard panel sizes are used.
SE_LONG: Southeast Longitude. This is the longitude of the southeast corner of the FIRM panel. This value is in degrees, minutes, seconds (DDD MM SS.SSS). Normally this corresponds to USGS 7.5' quadrangle maps using NAD83, or even subdivisions thereof. However this value should reflect the actual longitude if non-standard panel sizes are used.
SOURCE_CIT: Source Citation. Abbreviation used in the metadata file when describing the source information for the S_FIRM_Pan table.
CTY_ABBR: DNR County Name Abbreviation (four letter)
Data Elements for Attribute Table cross_sections:
XS_LN_TYP: Cross-Section Line Type. This attribute should contain 'LETTERED' for cross sections that are shown on the hardcopy FIRM. If the cross section will not be shown on the hardcopy FIRM, this attribute should contain 'NOT LETTERED' to indicate that the cross section is part of the backup data for the study, but is not shown on the FIRM.
WTR_NM: Surface Water Feature Name Lookup Identification. A code that provides a link to the name of the water feature associated with the cross section. The water feature name is taken from the table L_Wtr_Nm. This is a lookup table that is populated by the creator of the database.
WSEL_REG: Regulatory Water-Surface Elevation for the 1-Percent-Annual-Chance Flood Event. This is the precise water surface elevation of the base flood calculated at this cross section. This elevation exactly matches the elevation of the base flood in the Flood Profiles and the Floodway Data table. This number is determined during the engineering analysis for the study. This value should match the regulatory column in the Floodway Data table in the FIS report or the elevation from the corresponding flood profile if no Floodway Data table is published.
XS_LTR: Cross-Section Letter. The letter or number that is assigned to the cross section on the hardcopy FIRM and in the FIS report. This attribute is blank if the cross section is not shown on the FIRM. For a digital conversion, only cross sections that are shown on the FIRM will be available.
START_ID: Start Identification. This is a link to the station start lookup table. The station start describes the origin for the measurements in the STREAM_STN field. This field should contain a number that links to a unique value in the START_ID field in the L_Stn_Start table.
STREAM_STN: Stream Station. This is the measurement along the stream to the cross-section location. Normally this information is available in the Floodway Data table in the FIS report. When no Floodway Data table is published, this value can be read from the horizontal scale of the flood profile. The units are clarified in the description in the START_DESC field in the L_Stn_Start table.
LEN_UNIT: Length Unit Lookup Identification. A code that provides a link to valid unit of length from the D_Length_Units table. The unit specifies the system of measurement for the water surface elevation. For the Enhanced Database, this attribute also specifies the length unit for stream bed elevation and top width. Normally this would be feet.
V_DATUM: Vertical Datum Lookup Identification. A code that provides a link to a valid vertical datum from the D_V_Datum table. The vertical datum indicates the reference surface from which the flood elevations are measured. Normally this would be North American Vertical Datum of 1988 for new studies.
SOURCE_CIT: Source Citation. Abbreviation used in the metadata file when describing the source information for the S_XS table. Table:
CTY_ABBR: DNR County Name Abbreviation (four letter)
Detailed Citation:
Value Domain for Data Element CTY_ABBR:
AITK = Aitkin
ANOK = Anoka
BECK = Becker
BELT = Beltrami
BENT = Benton
BIGS = Big Stone
BLUE = Blue Earth
BROW = Brown
CARL = Carlton
CARV = Carver
CASS = Cass
CHIP = Chippewa
CHIS = Chisago
CLAY = Clay
CLEA = Clearwater
COOK = Cook
COTT = Cottonwood
CROW = Crow Wing
DAKO = Dakota
DODG = Dodge
DOUG = Douglas
FARI = Faribault
FILL = Fillmore
FREE = Freeborn
GOOD = Goodhue
GRAN = Grant
HENN = Hennepin
HOUS = Houston
HUBB = Hubbard
ISAN = Isanti
ITAS = Itasca
JACK = Jackson
KANA = Kanabec
KAND = Kandiyohi
KITT = Kittson
KOOC = Koochiching
LACQ = Lac Qui Parle
LAKE = Lake
LOTW = Lake of the Woods
LESU = Le Sueur
LINC = Lincoln
LYON = Lyon
MCLE = McLeod
MAHN = Mahnomen
MARS = Marshall
MART = Martin
MEEK = Meeker
MILL = Mille Lacs
MORR = Morrison
MOWE = Mower
MURR = Murray
NICO = Nicollet
NOBL = Nobles
NORM = Norman
OLMS = Olmsted
OTTE = Otter Tail
PENN = Pennington
PINE = Pine
PIPE = Pipestone
POLK = Polk
POPE = Pope
RAMS = Ramsey
REDL = Red Lake
REDW = Redwood
RENV = Renville
RICE = Rice
ROCK = Rock
ROSE = Roseau
STLO = St. Louis
SCOT = Scott
SHER = Sherburne
SIBL = Sibley
STEA = Stearns
STEE = Steele
STEV = Stevens
SWIF = Swift
TODD = Todd
TRAV = Traverse
WABA = Wabasha
WADE = Wadena
WASE = Waseca
WASH = Washington
WATO = Watonwan
WILK = Wilkin
WINO = Winona
WRIG = Wright
YELL = Yellow Medicine
Table Detail:
Section 6: Distribution
Publisher:
Minnesota Department of Natural Resources (MNDNR)
Publication Date:
01/01/2006
Contact Person Information:
Zeb Thomas,
GIS Data Systems Coordinator
Minnesota Department of Natural Resources
500 Lafayette Rd
St. Paul,
MN
55155-4011
Phone: 651-259-5637
Email: zeb.thomas@state.mn.us
Distributor's Data Set Identifier:
water_dnr_fema_dfirm
Ordering Instructions:
Please visit the download page for this dataset on the Minnesota Geospatial Commons website using the web link below (Online Linkage). Online Linkage: I AGREE
to the notice in "Distribution Liability" above. Clicking to agree will either begin the download process, link to a service, or provide more instructions. See "Ordering Instructions" above for details.
Section 7: Metadata Reference
Metadata Date:
02/23/2021
Contact Person Information:
Zeb Thomas,
GIS Data Systems Coordinator
Minnesota Department of Natural Resources
500 Lafayette Rd
St. Paul,
MN
55155-4011
Phone: 651-259-5637
Email: zeb.thomas@state.mn.us
Metadata Standard Name:
Minnesota Geographic Metadata Guidelines
Metadata Standard Version:
1.2
