Vertical Datum

The National Geodetic Survey (NGS) has determined that it was necessary to readjust the national vertical control network. The current reference is in the National Geodetic Vertical Datum of 1929 (NGVD 29). The vast majority of products of the Federal Emergency Management Agency, National Flood Insurance Program (NFIIP), which is administered by the Federal Insurance Administration (FIA), are currently referenced to NGVD 29 for vertical control data (ground, structure, and flood elevations). To remain in compliance with the national standard, FIA will be converting its products to the new national datum, as mandated by Congress the North American Vertical Datum of 1988 (NAVD 88). This conversion will necessarily take place in a gradual process driven by the opportunity to republish our Flood Insurance Studies (FISs) and Flood Insurance Rate Maps (FIRMs) for other substantive reasons.

Sea Level Increase Assessments

The National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center provides skills and information to state and local coastal programs. Focus areas include hazards, conservation, and coastal and ocean planning. Throughout fiscal year 2008, the Center continued to provide coastal resource managers with the information, tools, technical capacity, and expertise needed to effectively manage and protect the Nation's coastal communities.

View information on sea levels:

  • NOAA Coastal Service Center    
  • Sea Levels Online    
  • Sea Level Rise and Coastal Flooding Impact
  • Sea Level Rise and Coastal Flooding Impacts Viewer


View National Geodetic Survey Information: