DONALDSONVILLE — About one-fifth of the homes in Ascension Parish reviewed so far for flood damage have crossed a national flood insurance threshold that could require home elevation, demolition or removal, parish officials said Thursday.

But those homes are from just a small sample of the 6,000 to 7,000 homes that parish officials expect they and FEMA contractors will eventually have to review.

That small sample constituted properties about which homeowners had sought out parish officials, and a top parish planning official told the Parish Council Thursday that he expects the final percentage of homes over the federal damage threshold will be much lower.

"Most of the people who are calling us know that they've had a lot of damage in their house, and they've been asking us to do the assessments for them and so that ... percentage will very likely go down when we get the FEMA operators in the field," Jerome Fournier, parish planning and development director, said at the courthouse in Donaldsonville.

Parish inspectors took an early swipe at damaged homes and found 96 of 468 had what's known as "substantial damage," Fournier said.

The determination is important. Homes over the 50 percent damage mark have substantial damage. Substantially damaged homes that are also in the 100-year flood plain and also have a ground floor below the estimated height of the 100-year flood must elevate under the National Flood Insurance Program.

A 100-year flood is one that has a 1 percent chance of happen in a given year. The height of water that FEMA has estimated for a 100-year flood is known as the base flood elevation. In Ascension, new homes and substantially damaged homes must be a foot above the base flood elevation.

Fournier's report prompted concerns from councilmen about how residents with no flood insurance and limited resources would be able to elevate and whether any government agency could force people to elevate or move.

"What will happen to them if they say, 'I'm putting my house back together, and I'm staying here,'" Councilman Todd Lambert asked Fournier. "What's going to happen to them?"

Fournier said property owners can appeal substantial damage findings, but, for those whose appeal does not work, FEMA will allow residents to stay in their homes two years out of compliance.

Fournier said FEMA has told the parish that it has to enforce the rules of the National Flood Insurance Program that are built into Ascension's development laws. 

"They're telling us that because you agreed to these stipulations in the insurance policy, you have to ... make the homeowner comply regardless," Fournier said.

Parish President Kenny Matassa added that he told national flood insurance officials on Wednesday that the parish was not tearing anyone's house down.

"They said, 'If we do not comply with the law, they will take Ascension out of the flood insurance program.' They can do that," Matassa said.

He and Fournier said federal elevation grants are expected to be available at some point to help residents raise their homes, though that wasn't much comfort for some council members.

As far as damage assessments, Fournier said a major push with FEMA started Thursday as contractors worked in Sorrento and Gonzales. They were expected to start in the unincorporated parts of Ascension Monday.

Ten teams of two people each will be working with a parish worker to ensure the assessment methods match what the parish has been doing, Fournier said. 

In related action, the Parish Council adopted an ordinance that removes the "record inundation" as an elevation benchmark for new and substantially damaged homes. Matassa had already suspended this rule temporarily.

Parish officials said National Flood Insurance Program officials told them the change won't affect flood insurance rates.

Follow David J. Mitchell on Twitter, @NewsieDave.