The U.S. Army Corps of Engineers has announced it will open Morganza Spillway sometime between Saturday and Tuesday to ease the pressure of the rapidly rising waters of the Mississippi River.

The river is expected to crest May 22 at 47.5 feet in Baton Rouge, a level that will put water at the top of the Corps’ levees there. Opening the spillway locks is predicted to lower that crest by a foot or more.

If the spillway, which was built in 1954 and has not been used since 1973, is not opened, Corps officials predict levees south of Baton Rouge to be overtopped.

“If we operate Morganza, there won’t be overtopping,” said U.S. Army Maj. Gen. Michael Walsh of the Corps of Engineers. “If we don’t operate Morganza...about three miles south of Baton Rouge, we will have significant overtopping there.”

Walsh added, during a telephone press conference with the Pointe Coupee Banner Tuesday, different portions of the levee would be overtopped along a 200-mile stretch of the Mississippi River south of Baton Rouge.

When the spilllway opens will be closed in both directions for at least two hours and possibly as long as four hours, according to the Louisiana State Police. Currently a message sign warns motorists not to stop along the Morganza Spillway.

The spillway will be opened slowly, on bay at a time, to allow wildlife to escape downstream. At least half of the bays will be opened.

A similar sign has been installed in Simmesport at Lettsworth at the each entrance to the Atchafalaya Bridge.