North Carolina uses FEMA flood maps

North Carolina Floodplain Mapping Program

North Carolina will be the first state to profit from the Federal Emergency Management Agency's decision several years ago to digitize all of its U.S. floodplain maps, a move that could save lives and millions of dollars when hurricanes hit.

When Hurricane Floyd lashed the state in 1999, the paper-based maps FEMA officials used to predict where flooding was most likely to occur were out-of-date and inaccurate. The storm caused more than $3.5 billion worth of damage and killed about 40 people.

But digitized maps, built using a new 100-data-layer geographic information system (GIS), are accurate to within 25 cm, according to John Dorman, program director of the North Carolina Floodplain Mapping Program. The final database, covering all the state's 100 counties, will hold up to 20 terabytes of data.

And it could also be the basis for a number of other programs, helping the state leverage scarce funds.

The accuracy of the elevation data in the GIS means North Carolina's Transportation Department can cut around 18 months of road construction projects, Dorman said. The detail provided by the many layers of data also allows for extensive modeling of situations such as chemical spills and other potential hazards that will help improve the state's risk assessments for post-Sept. 11, 2001, emergency planning.

"We think it would actually be a disservice if we only limited the program to floodplain mapping," he said. "It's morphing into a more multihazard mapping program, which is what FEMA has been trying to do all along."

The state expects to save around $56 million a year in reduced flood damage alone with the new GIS, Dorman said.

The GIS was built using a Unisys Corp. ES 7000 enterprise server and a Microsoft Corp. Windows 2000 Datacenter server. The prime contractor for the program was Watershed Concepts.

Robinson is a freelance journalist based in Portland, Ore. He can be reached at hullite@mindspring.com.