Map Modernization in Rhode Island

In recognition of the devastating flood impacts Americans receive each year, the United States Congress authorized a program and provided funding to update the Nation's inventory of Flood Insurance Rate Maps (FIRMs). This multi-year funding has allowed FEMA and its partners to undertake the massive project of updating and digitizing flood maps across the country to more accurately reflect the true flood hazard risks. This initial modernization process is nearing completion across the country.

The program has or will create digital Flood Insurance Rate Maps (DFIRMs) for communities participating in the National Flood Insurance Program (NFIP).  As flood hazard data is updated, the flood map inventory becomes a digital map system enabling officials at all levels of government to assess risks using geographic information systems and additional digital data.  Additionally, the intent of the new digital maps is to increase the frequency of updates to the maps and perhaps reflect current flood hazards more accurately.

The FIRM updates from the map modernization program have also converted the data to the North American Vertical Datum of 1988 (NAVD 88).  In recent years, the National Geodetic Survey has moved from a national vertical control network based on National Geodetic Vertical Datum of 1929 (NGVD 29) to NAVD 88 data.  To remain in agreement with the national standard, the Federal Emergency Management Agency (FEMA) has been converting its products to the national datum, NAVD 88.  In accordance with this conversion, the effective FISs and FIRMs fro Providence County have been developed using NAVD 88.  Washington, Kent, and Newport Counties will also be converted as the maps are updated.  Unfortunately, because Bristol County was digitized early in the Map Mod process, the maps are still using NGVD 29. The specific conversion factor(s) used to convert the flood hazard data for your community from NGVD 29 to NAVD 88 will be found in the FIS.

For more information, check out FEMA’s Map Modernization website.

Click here for the current status of Rhode Island Flood Maps.

Transition to Digital Flood Data

It is important to note that with the new digital map format, FEMA is moving towards digital distribution.  Beginning with flood maps distributed on or after October 1, 2009, FEMA will provide a single paper map and Flood Insurance Study (FIS) to each community when their maps are updated and will convert all other distribution of maps and FIS reports to digital delivery.

The Floodplain Management Program will maintain both paper and digital copies of all Rhode Island FIRMs and can assist you in obtaining flood hazard information.

Flood Insurance Rate Map Data Accuracy

It is important to recognize that the DFIRMs are only as accurate as the available data.  In many areas, new development and storm impacts may have changed the physical environment such that the actual risks are no longer depicted on the flood maps.  The only way to ensure accurate up-to-date maps depicting true hazards, is to include better data.  If you have or know of a project which included the collection of:

• Digital topographic mapping,
• Digital terrain models,
• Digital orthophotos,
• Transportation data,
• Updated corporate boundaries,
• High water marks,
• Hydrologic and hydraulic data, and/or
• Design data for bridges, dams, stream channels and flood control measures

Contact the State Floodplain Management Program.  We may be able to use the information to update your local flood maps.