After a 90-day appeals period for proposed new flood maps began Thursday, the city of Suffolk’s planning director has encouraged property owners to apprise themselves of their calculated risk of inundation.

“I would certainly recommend that people be aware of their flood risk and know whether they are in a flood-prone area or not,” Scott Mills said.

Mills estimated that about 150 folks attended a public meeting on the Federal Emergency Management Agency’s proposed updated Flood Insurance Rate Maps for Suffolk, held at King’s Fork Middle School on Wednesday.

The city has also sent out “a great number of notices” on the maps to property owners, he said.

“I think we have done everything we can to educate and make people area,” Mills said.

Insurance companies use FIRMs maps — an acronym by which they are more commonly known — to determine flood insurance rates. Dividing flood-prone areas into zones, the maps indicate levels of flood risk.

The proposed new maps, first issued to the city in December, update the old maps that have been in effect since November 2011.

“There may be a little bit of increase here, and a little bit of decrease there,” Mills said. “One of the things we recognized with the new maps — they are based on a lot more detailed information than the existing maps.”

Some base flood elevations — the computed elevation to which floodwater is anticipated to rise during the base flood — have risen, according to Mills.

“We haven’t analyzed every single piece of property,” he said. “We have some elevation changes where base flood elevation may have increased.”

The new maps use “more-accurate topography, and model it over a longer distance,” said Shanda Davenport, the city’s principal planner.

“They have gone through and broken it up into multiple elevations,” she said.

“In some cases, the elevation may have gone up, but in some cases it may have gotten smaller, since they have more-accurate topography.”

Any appeal against a property’s designation has to be “a very technical appeal,” Mills said. “We have to have some type of sound scientific data.”

At the end of the appeals period, he said, the city has six months to adopt a revised flood plan ordinance and updated maps, or it will be suspended from the National Flood Insurance Program. “That (would) result in increased premiums for homeowners required to have flood insurance,” Mills said.

Additional information is available at www.R3Coastal.com, and the proposed new maps are at www.rampp-team.com/va.htm.

Information on the appeals process can be found on the Federal Emergency Management Agency’s website at www.floodmaps.fema.gov.