By Kevin Litten
The Roanoke Times, Va.

ROANOKE, Va. — Montgomery County planning officials will make new flood mapping information available for the public to review Monday. Changes to the county's floodplain could mean insurance premium changes in about 5 percent of the county's households.

The maps are the result of an aerial laser technology program that the state tested in the county in 2005. The technology tracks changes in the topography at much higher detail than was done in the 1970s, when the county created its first flood maps, which are still in use today.

Having more detailed maps means the county will know with much greater certainty whether homes are in danger of catastrophic flooding, but it also means some residents could be considered in a flood area even if they weren't before.

The old maps, according to county maps specialist Bob Pearsall, may have "created a larger floodplain than necessary and more people were in the floodplain than needed to be." But in other areas, the flood area might turn out to be smaller than expected.

"That's the duality of what we do," Pearsall said.

Local flood mapping is managed at the federal level through a flood insurance program, but Montgomery County had not updated its maps since that program took effect in the 1970s, said Joe Powers, the county's former planning director who is working part time on the flood maps.

Dave Odegard, a Federal Emergency Management Agency insurance specialist, said it's important for Montgomery County residents to view the maps and determine their risk level. If residents know they have been mapped into an area at risk of flooding before the new maps take effect, they should buy a lower-cost, preferred-risk policy, he said.

"If they do it right before the map changes, when they renew they'll have saved a good amount at a pretty good rate," Odegard said. "What normally happens is the map changes and people don't buy flood insurance until they're notified by the insurance company."

If they wait until then, the premiums tend to be higher, Odegard said. Residents should also view the maps because mortgage companies will sometimes require insurance of homeowners who are in borderline areas.

Odegard said residents can appeal decisions about where they are in the floodplain. "What I think we want people to do is make an informed decision. Just because the bank says you're in doesn't mean you're in," he said.

On average, flood insurance premiums cost $512 annually. Homeowners in areas with 1 percent risk should expect to pay about $800, Odegard said.

Montgomery County officials expect the new maps to take effect sometime in January but have not received a date from FEMA.

Getting access to the maps depends on the locality residents live in.

In Blacksburg, residents should go to the engineering department in the town's municipal building at 300 S. Main St. In Christiansburg, residents should go to the town's planning department at the municipal building at 100 E. Main St.

All other residents can view the maps at the county's planning department within the government center at 755 Roanoke St.

Copyright 2008 The Roanoke Times