Cities say new FEMA flood maps contain many errors

There is a stream that appears on aerial maps that isn’t in the same place on the new digital maps, he said. “You overlay the maps and it’s just not the same,” Beck said. “It’s in a different location. And the new maps for Barre, Vt., predict that 20 percent more water would enter the city’s business district than the current maps predict,” said Mike Miller, the city’s planning director. He said the maps will hamper redevelopment projects, and that the city is deciding whether to appeal to change the maps.

Josh deBerge, a FEMA spokesman based in Kansas City, Missouri, said there are few substantial changes in the new FEMA maps, and that any major changes were made because advances in mapping technology allowed for better analysis. “When home and business-owners know and understand their risk, they are more likely to take steps to reduce their risk,” deBerge said.

FEMA welcomes criticism of the digital maps and is open to making changes if a compelling scientific case can be made, deBerge said. “What we’re looking for is evidence, a study or survey that would provide more detailed information that can be incorporated,” deBerge said.

Generally, it takes about eighteen months from the time a preliminary map is released to when it takes effect. During that time, FEMA holds community meetings followed a 90-day appeal process and a FEMA review of concerns raised during the appeals process. Once an appeal is resolved, FEMA issues a letter of final determination and provides the final map to the community.

If a challenge fails, communities may be stuck changing land use and development plans — a process that could take up to six months before a new map takes effect.

Residents may have to pay thousands of dollars on surveys to prove they should be exempted from the maps, and in some cases could be forced to elevate their homes.

John Bishop, a project manager for Illinois’ Floodplain Mapping Program, which was contracted to work on that state’s digital maps, said Congress appropriated money for the re-mapping project but not for new engineering studies. He said one problem was that FEMA started with maps up to twenty years old, then put them into digital form, making improvements where possible. In some cases, new land development has changed water flow and runoff patterns since the maps were first drawn. He said, though, that most of the problems (in Illinois) have been corrected, and that the new maps will be more precise and easier to correct once new data become available.