West Bank residents are worrying about proposed Federal Emergency Management Agency flood maps that put most of Algiers Point into a higher-risk flood zone, which could mean higher flood insurance rates and mandatory coverage for some homeowners.

Some Algiers residents plan to fight the change, which resident Vlad Ghelase said is flawed and could lead to catastrophic changes to the neighborhood if many property owners are forced out because of higher prices.

“In the long run, I think there’s going to be a big crunch in the market and there’s going to be a lot of foreclosures,” said Ghelase, an architect.

The preliminary flood maps were released earlier this year, but Ghelase said many in the neighborhood are only just hearing about the change and starting to organize an appeal. Residents have until Aug. 6 to file appeals to change their flood zone.

Algiers has been in Flood Zone X, which means officials think it would not flood during a storm that has a 1 percent chance of occurring any year. In the new maps, however, many properties in and around Algiers Point are reclassified into an A Zone, indicating they could flood during such a storm.

Financially, the difference can be significant. Not only is flood insurance more expensive in an A zone, but many mortgage companies require property owners to obtain it for homes in such areas. Flood insurance is optional in the X Zone.

There also are caps on the amount that flood insurance rates can increase in areas not considered to be at a significant risk of flooding.

The change came after FEMA recalculated the risk of flooding during massive rain events, ones that have a 1 percent chance of occurring in any year.

Based on new projections from a variety of federal agencies, the total rainfall that would be expected in such an event was increased from 12.57 inches in 24 hours to 14.25 inches in the same time period, changing the extent of predicted flooding, said Stephanie Moffet, a spokeswoman for the agency.

At the same time, new imaging of the area showed a more severe slope from the levees along the Mississippi River to the internal areas of Algiers, meaning the internal areas are at a lower elevation than previously thought, Moffet said. That means buildings in those areas would need to be raised to a higher elevation to be high enough to avoid flooding, according to the maps.

The issue has already been hashed out, to an extent. In 2013, Mayor Mitch Landrieu’s administration filed an appeal challenging the elevations used by FEMA on the West Bank. While it was successful, the changes made by FEMA did not move the area back into the lower-risk category.

Overall, most property owners in the city will benefit from the new maps, which, because of the certification of the area’s improved levee system, now show most areas as having a lower flood risk than previously. About 53 percent of the city’s residents will move into the X Zone, while about 3 percent have been downgraded and are now in the A Zone, according to city estimates.

Ghelase said the change made by FEMA doesn’t square with the facts on the ground in Algiers. Some of the areas now listed in the more expensive zone because they are considered to be below “base flood elevation” — the elevation needed to be above the risk of flooding — are actually higher than those which did not see their status change, said Ghelase, who owns a home and six other properties in the neighborhood.

In addition, he said, there’s no evidence of significant changes in elevation due to subsidence or other factors that would justify changes to an area that didn’t flood during Hurricane Katrina or other major storms.

About 50 Algiers residents are planning to get their properties surveyed in an attempt to show they are above base flood elevation and then to fight the change, Ghelase said.

Follow Jeff Adelson on Twitter, @jadelson.