The Federal Emergency Management Agency is updating and revising its Flood Insurance Rate Maps, and more than 300 Linn County properties are to be added, while another 600-plus are to be dropped.

The map review period officially opened June 22 and will end on July 22, but county officials are asking for an extension so the people affected have a chance to be on the record.

"It doesn't appear FEMA is required to notify property owners, and we think they have a right to know," said Roger Nyquist, Linn County board chairman.

"They have yet to schedule to public meeting that is supposed to happen," said Steve Barnett, manager of the Linn County Geographic Information System. "It is required by law, but there is nothing that says it has to be in the review period."

A meeting is tentatively scheduled for early August, but no date or time has been set.

The county began mailing letters to those affected by the 100-year flood plain boundary change this week.

"We are getting a net decrease in the flood plain, but it's shifting," Barnett said.

FEMA has not completed a flood plain review since the late 1980s, Barnett said. "They didn't actually go out and do any flood plain analysis this time," he said.

Using data already on hand, FEMA refined the map from 40-foot contour lines to 2-foot contour lines.

The new map adds more than houses and other structures to the flood plain.

"There are people that are going to see their back yard is now in the flood plain," Barnett said. "Because their house isn't in, it won't matter for flood insurance, but if they want to go build something in their backyard, suddenly, it's in the flood plain."

That could affect the permit process and the homeowner's ability to build on the property. For example, in some cases people would have to elevate the structure.

To find out if your home is on the new flood plain map, go to www.co.linn.or.us/floodmap and type in your address.