Kim Duplantier's three-story colonial plantation-style home survived Hurricane Katrina, albeit with 3 feet of unwelcome water on the bottom floor.

But Isaac, still a hurricane when it made landfall in Louisiana, had something more in mind.

The slow-moving storm presented an insidious calling card after heavy rains "overtopped" a levee in the town of Braithwaite in Plaquemines Parish.

At 4:30 a.m. Wednesday, Duplantier said, a couple of inches of water were evident in her redbrick home and in her parents' residence nearby.

At 6 a.m., there was 4 feet of water.

By 7 a.m., her bedroom, an antique grand piano, a grandfather clock and a whole lot more were inundated by 9 feet of water.

"We were very prepared," said Duplantier, who had evacuated Monday with her children to New Orleans while her husband and parents stayed behind.

The family was coping with the latest weather disaster in Plaquemines Parish, where dozens of people were rescued Wednesday and as many as 800 homes suffered significant water damage. The parish is just southeast of New Orleans.

Quoting her 17-year-old son, Duplantier said, "Katrina took away the shock value."

Plaquemines Parish, split into the East Bank and West Bank by the Mississippi River, appeared to be the epicenter of Isaac's wrath.

The Duplantiers live on the East Bank. It was the back levee, one of two, that overtopped Wednesday.

Officials were considering intentionally breaching the levee, a second line of flood defense, to allow some of the floodwater to flow back out of the inundated area, Gov. Bobby Jindal said.

According to The Times-Picayune, the digging might begin Thursday. Garret Graves, chair of the Coastal Protection and Restoration Authority, told the paper that the state had agreed to the plan to start digging as soon as conditions allow.

Parish president Billy Nungesser said Wednesday evening that crews will travel to the area Thursday morning by air boat to study the situation.

"We have to wait for the water to be out enough to see the levee," he said.

If the decision is made to cut the levee, it likely won't happen before Saturday, according to Nungesser.

The receding water would flow back into the marsh and would not affect other communities, Nungesser said.

Meanwhile, about 3,000 parish residents remained in one area close to an 8-foot tall West Bank levee that waters were threatening Wednesday evening, according to Jindal's office.

A mandatory evacuation was ordered south of Belle Chasse because models show the water will reach 8 feet.

The National Guard, meanwhile, evacuated 112 residents from the Riverbend nursing home in Belle Chasse, officials said.

Nungesser said at least four levees were overtopped, creating a kind of flooding the parish did not see even during Hurricane Katrina, which hit seven years ago Wednesday.

"This storm kept pumping that water for days up against the levees," said Nungesser. "Something had to give."

The waterlogged parish is asking for President Barack Obama to declare a local federal disaster, making it eligible for assistance. "That is going to be so needed," said Nungesser.

More than 150 calls came in to 911 from people wanting to be rescued, said Terry Rutherford, commander of authorities in Plaquemines Parish, after the levee on the East Bank overtopped.

By mid-morning, 75 people had been rescued from flooded homes and rooftops in Braithwaite, CNN affiliate WWL reported.