U.S. Army Corps of Engineers officials told St. Mary Parish residents Thursday that the Morganza Spillway flood controls could be opened Monday, and to prepare for flood levels at least equal to those of 2011, the last time the corps opened the flood valves and sent Mississippi River water rushing toward Morgan City.

Corps and parish officials said the Atchafalaya River, which flows between Morgan City and Berwick, could reach flood levels in a few weeks, especially if the corps opens Morganza. The Atchafalaya is expected to crest around Jan. 23.

Thursday afternoon, Corps officials in New Orleans said a decision on Morganza could be made Thursday night or Friday.

Corps Col. Richard Hansen said even if Morganza is not opened to divert water from the Mississippi River, the corps still expects flooding in St. Mary Parish.

Hanson and other corps and parish officials Thursday addressed over 300 people at the Morgan City Auditorium, one of several flood-preparation meetings being held this week across south Louisiana.

“Now is the time to take temporary flooding measures,” Hansen said.

This week Corps officials and parish employees have monitored parish levees for sand boils, Hansen said. Sand boils form on the dry side of levee when water seeps under the structure and weakens it.

They also are looking for cracks in the levees, he said, and are watching big boat traffic on the area’s many waterways for signs that they may be passing too close to the levees.

About 130 National Guard troops from the 256th Infantry Brigade and the 225th Engineering Brigade were due Thursday evening at the Amelia recreation center on the east end of the parish to set up a command center.

On Friday guardsmen will unload earth moving equipment for flood diversion work on Avoca Island, Guard Maj. John Williams Jr. said. Avoca Island lies about three miles southeast of Morgan City near Lake Palourde.

For commercial boats, east-west boat traffic on the Intracoastal Canal should not be affected by rising water, the Coast Guard said, but north-south boat traffic on the Atchafalaya River could be closed in Morgan City if the water rises to the level of the railroad bridge crossing the river.

Hunters, meanwhile, could face a shortened deer and duck hunting season, though the parish’s boat launches remain open for now for those who want to secure their camps. Corps Chief of Emergency Operations Mike Stack said he could not say how long the launches would remain open.

To the north, in Centerville and Franklin, homes and businesses along Bayou Teche should not see rising water due to a rising Atchafalaya, St. Mary Parish President Paul Naquin said. Flood control systems for the Teche located north of Morgan City have been closed, he said.

On Thursday the Coast Guard said in a release that it would reopen boat traffic on Bayou Chene, located near Morgan City. But the agency said it would close the bayou again Saturday morning to install a “flood protection structure,” a barge that will be sunk in the waterway to divert water into adjacent marshes instead of into low-lying communities. The barge project was first tried in the 2011 flood and is credited with preventing damage.

Also on Thursday, the St. Martin Parish Sheriff’s Office said it would begin supplying sandbags for residents and businesses on the parish’s eastern section, which includes the community of Stephensville to the north of Morgan City.

Residents are urged to monitor the websites and social media sites of St. Mary Parish Office of Homeland Security and Emergency Preparedness at stmaryohsep.org, the Army Corps of Engineers site at mvn.usace.army.mil