NORCO, La. (AP) — As residents in parts of Louisiana along the swollen Mississippi River started preparing for possible evacuations, the Army Corps of Engineers opened a spillway Monday to protect the New Orleans area from the river’s rising waters.

To ease pressure on the greater New Orleans levee system, the corps partially opened the Bonnet Carre Spillway for only the 10th time since it was completed in 1931. Several hundred curiosity-seekers watched from the bank as workers used cranes to remove some of the spillway’s wooden barriers, which serve as a dam against the high water.

The corps also has asked for permission to open the Morganza spillway north of Baton Rouge, which diverts river water into the Atchafalaya Basin. Completed by the corps in 1954, it hasn’t been opened since 1973. Major General Michael J. Walsh, president of the Mississippi River Commission, was expected to make the decision as early as Monday.

“You could start to see water flowing as early as the end of this week,” Gov. Bobby Jindal said.

Jindal has requested three to five days to evacuate folks, if the decision is made to open it.

“We’ve already seen some sheriffs go and provide notifications to folks that they may want to think about evacuating. We’ve seen some folks move their property to higher ground,” said Jindal.

Concordia Parish, upriver from Baton Rouge, encouraged residents on Monday to start packing up valuables in preparation for a possible evacuation of homes.

“We’re just advising people to be aware and stay alert,” said Concordia Parish Police Jury President Melvin Ferrington. “The last thing we want to do is cause a panic.”

Many residents seemed unconcerned about the rising water. Melinda Washington, who lives in one of the modest houses strung along the foot of the levee in Vidalia, said she wasn’t even following news reports of the river’s rise.

“I’ve lived here all my life,” the 60-year-old woman said, “and it’s never gotten above the bottom of the levee, let alone over it.”

The Bonnet Carre Spillway, which the corps built about 30 miles upriver from New Orleans in response to the great flood of 1927, last opened during the spring 2008.

Rufus Harris Jr., 87, said his family moved to New Orleans in 1927 only months after the flood killed hundreds of people and displaced more than 700,000 others from their homes. He was too young to remember those days, but the stories he heard gave him a healthy respect for the power of the river.

“People have a right to be concerned in this area because there’s always a possibility of a levee having a defective spot,” Harris said as he watched water pour through the spillway’s bays.

The Corps planned to open 28 of the spillway’s 350 bays on Monday. Col. Ed Fleming, commander of the corps’ New Orleans district, said officials will monitor the river levels before deciding whether to open more bays.

Plaquemines Parish President Billy Nungesser, who watched the spillway’s opening from an area reserved for officials, said high water isn’t likely to force evacuations in his parish.

“It’s nothing to panic about, but it’s obviously a concern we have,” he said.

State officials moved some prisoners from the Angola state penitentiary in West Feliciana Parish, north of Baton Rouge, as backwaters rose. Eight buses and several vans under police escort moved inmates with medical problems. A trailer carrying livestock left the facility, which includes a farm in its operations.

Nearly 200 people were evacuated, though more could be taken out later. Inside the prison, some prisoners were being moved to less vulnerable buildings.

Jindal said areas outside of those impacted directly by the rivers or the spillways, particularly communities on tributaries in north Louisiana, should be on alert.

“Those that were flooded in 2008 can expect to be flooded again, mainly due to backwater flooding,” said Jindal. He said that those areas should not expect to see water until the crest hits Louisiana in roughly two weeks.

The Bonnet Carre diverts river water into Lake Pontchartrain and from there into the Gulf of Mexico. Opening all of its bays takes about 36 hours. The structure is designed to pass a maximum of 250,000 cubic feet of water per second. Morganza, which is composed of 125 gated openings, is designed to pass a maximum of 600,000 cubic feet of water per second and would take about 15 hours to completely open.

The Bonnet Carre spillway runs about 5.7 miles from the structure at the Mississippi River to Lake Pontchartrain. Officials project the Bonnet Carre spillway could be open for at least two weeks. It’s unclear when Morganza might be opened.

Pat Lafaye, 71, of Metairie, expressed confidence that the levees protecting greater New Orleans can hold back the high water.

“We went through Katrina and we did fine,” Lafaye said of her family’s home. “I’m too old to be worried.”