BUTTE LAROSE, La. (AP) — Ripples of fear rose Tuesday along the normally placid bayous of the Atchafalaya basin, the corridor through which a torrent of surging water could be unleashed if authorities decide in coming days to ease the strain on Mississippi River levees by opening the Morganza Spillway northwest of Baton Rouge.

On Tuesday, residents of the Cajun-country hamlet of Butte LaRose, about 30 miles west of Baton Rouge, packed up belongings to leave should the Morganza spillway be opened. Opening the spillway would pour floodwaters from the Mississippi into the Atchafalaya River for a 100-mile trek to the Gulf of Mexico. If the Army Corps of Engineeers decides to open the Morganza for the first time since the early 1970s, it would ease flood concerns in populous Baton rouge but flood a south Louisiana watershed dotted with fishing camps, rural homes and waters rich in fish, alligators and nutria.

“”Everybody is just scared. They don’t know what to do,” said St. Martin Parish Deputy Sheriff Ginny Higgins.

Higgins oversaw the work of parish jail inmates, clad in the black and white stripes reminiscent of another era, as they filled sandbags that residents could use try to protect their property if the spillway were to be opened.

“I wish we could do more for people, but you can’t fight the water,” Higgins said.

The area was last flooded in 1973, when high water on the Mississippi River forced the Army Corps of Engineers to open Morganza, a spillway completed in 1954.

On Monday, the corps began opening another spillway to the south, Bonnet Carre, seeking to take the pressure off the levees protecting New Orleans.

Gov. Bobby Jindal said Tuesday that communities along the Morganza spillway should be alert and ready for evacuations if authorities decide to open the Morganza.

Jindal said he expects a decision from the Army Corps of Engineers soon. The spillway runs from the Mississippi northwest of Baton Rouge to the Atchafalaya Basin and into the Gulf near Morgan City.

Jindal said he’s asked the corps for notice of at least three days’ notice so residents can be evacuated. The governor said the latest projection was for an opening as early as Saturday if it comes.

Pam Vidros, a spokeswoman for the corps, said a decision is likely in the next couple of days.

Louisiana home and business owners without flood insurance are on their own against the river. Insurance Commissioner Jim Donelon said flood coverage can still be purchased, but it won’t cover damage from rising water for 30 days.

Standard homeowners and business coverage won’t pay anything for flooding — just as after hurricanes — even if Morganza is opened to send flood water into the Atchafalaya Basin.

Donelon said thousands of properties are at risk.

Flood coverage is administered by a federal program. Donelon said that after hurricanes Katrina and Rita of 2005, the program paid out $15 billion in Louisiana.

As the Mississippi continued to rise in north Louisiana, officials were calling for calm while saying the situation was under control.

Reynold Minsky, president of a northeast Louisiana flood control agency, said he was dealing with panicky phone callers and “sand boils” — seepages of water along the Mississippi River levees his agency oversees.

He seemed more concerned by the calls.

“People need to be calm and quit panicking,” Minsky, president of the 5th Louisiana Levee District, said by telephone while on a break from a helicopter tour of the levee system. “Our levees, they’re not breaking. They’re in good shape.”

The sand boils — spots where water bubbles up on the land side of the levee — were being dealt with using sandbags, he said. He said he foresaw no danger of the levees in the district failing or being overtopped.

Farther south, there was more concern.

In Concordia Parish, workers built a system of eight-foot sandbag-and wire-mesh mini-levees around buildings along the Vidalia Riverfront — a strip of land between the Mississippi River and the levee, with a park, walking trail, a camp ground, and $75 million worth of buildings that include a convention center, hotel and medical center. The Riverwalk generates 300 jobs for Vidalia, a town of 5,000.

It seems counterintuitive to build on an area outside the towering levee designed to protect from river flooding, but Mayor Hyram Copeland said Monday that the area seemed safe enough when construction started in 1997.

“Each one of these is high enough to survive the 100-year flood,” Copeland said. “But this is the 500-year flood.”

The worst flooding in Vidalia occurred in 1938, when the Mississippi crested at 58.4 feet. On May 21, Copeland said the river was expected to crest at 64 feet — not high enough to flood the town, but enough to drown the Riverwalk. Aside from the hospital and businesses, the two wells that supply Vidalia with water are also located in the strip.

“If we lose those, we’ll be without water for about two months,” Copeland said. “You can imagine what a mess that would be.”

Although he is sure the buildings and wells will survive thanks to the newly installed barriers, the flood will have costs, Copeland said. Each of the businesses is empty, except for security personnel, and those 300 workers are sitting home waiting for the water to recede.

“It may be two months before they can open again,” Copeland said. “Can you imagine the losses for the hotel? The costs of evacuating all those patients?”

Vidalia alone has coughed up $2.5 million for the protection effort, a severe blow to the town’s budget, Copeland said.

Concordia Parish encouraged residents to start packing up valuables in preparation for a possible evacuation.

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