The Federal Emergency Management Agency's newly revised maps that determine which Augusta properties lie within flood hazard zones are almost ready for final adoption.

Though most flood-prone areas are well known from experience, the new maps -- the first broad revision in a decade -- are more detailed.

"Think of it like using a magnifying glass," said Jody Cottrill, the spokeswoman for FEMA's Region IV office in Atlanta. "Ten years ago it was one way, and now you're looking at all the tiny detail through a magnifying glass and will have a much better and more realistic understanding of your risk."

The maps are important to homeowners because, in situations where someone has a federally backed mortgage and the property is in a flood-prone area, the owner must purchase flood insurance.

"It is a federal law that governs mortgage lenders," Ms. Cottrill said. "The lenders will review portfolios of properties and look at which ones are in special flood hazard areas, and they will notify homeowners if they are now required to purchase flood insurance."

One key map change is the addition of a "shaded x" zone that identifies areas with a very slight chance of flooding. Property owners in such areas aren't required to buy flood insurance.

"It's a new designation for us, and these are areas with a 0.2 chance of flood," said Terri Turner, Augusta's assistant zoning and development administrator. "We have a lot of these areas on the new maps."

One such "shaded x" area is the Hyde Park area off Dan Bowles Road.

"The new map validates what many people already knew: that given enough rain, Hyde Park can flood," Ms. Turner said. "Now we know they have a minimal chance of flooding, where we didn't necessarily know that before."

Most of the most flood-prone areas in Augusta lie along the Savannah River and various creek drainages, though much of the county is protected by an extensive levee.

Though the new maps include flood-prone areas that might not have appeared on the old maps a decade ago, there are few surprises because the changes have been made gradually over the past decade.

"Every time there is a new study of a specific area, whether it be by a developer or DOT or whoever, there can be changes in the floodplain elevation," she said. "So the new maps would have new areas that are in the floodplain that were not in there before, but the property owners would have been notified a long time ago, by certified letters, at the time the changes were made."

Similarly, some areas formerly listed in flood zones, including a previously unstudied tract off Alexander Drive, are no longer under that designation in the new maps, though those changes occurred years ago.

"The new map incorporates changes made gradually over the past decade," she said. "It is an accurate reflection of what has gone on over the last 10 years, whether it was by Mother Nature or from new studies of a particular area."

The new maps, available for public review, could undergo revisions under a 90-day appeal and protest period. They are scheduled for final adoption later this year.

"People think of floods as being roaring water and houses swept off foundations," Ms. Cottrill said. "People sometimes don't realize you can have something like a wet carpet flood -- and you still have to replace wallboard and carpeting and it can cost a lot of money."