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fLoodplain Management Program
Home > Programs > Floodplain Management > Mapping > History of Floodplain Mapping in Maine

Floodplain Management

Floodplain Mapping in Maine

The National Flood Insurance Act of 1968

This created the National Flood Insurance Program (NFIP) and required
The identification and publication of information within five years for all floodplain areas that have special flood hazards
The establishment of flood-risk zones in all such areas to be completed over a 15 year period following the passage of the Act.
Housing and Urban Development Act of 1969

    

There was an immediate recognition that scientific mapping of floodways couldn’t be done within the time frame specified so the act was amended in 1969 to authorize the Emergency Program which allowed for the creation of Flood Hazard Boundary Maps (FHBM) or “Flat Maps” These maps have very little information on them and it is very difficult to determine whether a specific property is or is not within a floodplain.

The Flood Disaster Protection Act of 1973

Initiated a more extensive use of Flood Insurance Studies analyses to develop base flood elevations (BFE’s), designate floodways and risk zones for most NFIP communities using detailed hydraulic and hydrologic analysis. The Flood Insurance Studies were issued to the communities along with new Flood Insurance Rate Maps (FIRM’s) (link to FIRM Example) While these maps were meant to have a stronger scientific basis than the flood Hazard Boundary Maps in reality many of the new FIRMS were in reality reissued FHBM’s in the new FIRM format which allowed communities to move from the Emergency Insurance Program to the Regular Insurance Program.

Click Here for an image of a Floodplaine Insurance Rate Map from 1973

Note: Just because a community has been issued a Flood Insurance Study report doesn’t mean that the science behind the delineation of floodplains has been improved. Many of the old flat maps were updated through a letter of conversion. This allowed communities to join the REGULAR Flood Insurance Program that allowed for higher insurance coverage’s rather than continue in the EMERGENCY program where insurance maximums were considerably less.

 

1976 FEMA Special Conversion Process

At about this time FEMA determined that communities with minimal development pressures did not require detailed Flood Insurance Studies because there were few existing buildings in the flood plain and minimal development pressure. Consequently FEMA adopted a process for admitting communities into the regular program without a Flood insurance Study. Flood Hazard Boundary Maps were converted to Flood Insurance Rate Maps where all special flood hazard areas were unnumbered A Zones without any BFE’s. Maine has a over 5000 lakes mapped in this category.

 

2003 to 2008 Map Modernization

In 2003 the United States Congress authorized a five year program to modernize and improve floodplain maps. The purpose of the program was to convert existing floodplain maps to a digital format and move to an electronic mapping format instead of a paper based system. It quickly became evident that just digitizing existing maps was not going to yield a sufficient quality map so FEMA adjusted the program to include more detailed analysis and development of underlying scientific data. The Maine Map Modernization effort is on going.

Note: Even with the new digital format there may be some areas of inaccuracy. A key factor in mapping floodplains is having high quality elevation data. Unfortunately most Maine communities still rely on outdated data acquired in the 1920’s and 1930’s.