Morganza Spillway in 1954, the Morganza Spillway has been opened twice (in 1973 and 2011), and considered for opening during four other major floods of the Lower Mississippi River. On April 17, 1973, in order to lower the water level of the Mississippi River and relieve pressure on the Old River Control Structure, the Corps of Engineers opened 42 of the 125 steel gates of the Morganza Spillway for the first time since its completion, allowing about half of its maximum designed flowrate to pass from the Mississippi into the Atchafalaya Basin. The spillway received minor scouring and slight damage to the
156th New York Volunteer Infantry to Baton Rouge, then to Donaldsonville, July 11-15, and duty there until August 15. At Baton Rouge until March 1864. Red River Campaign March 23-May 22. At Alexandria March 25-April 12. Cane River April 23-24. Construction of dam at Alexandria April 30-May 10. Actions at Alexandria May 2 and 9. Retreat to Morganza May 13-20. Mansura May 16. At Morganza until July. Expedition from Morganza to the Atchafalaya May 30-June 5. Atchafalaya River June 1. Moved to Fort Monroe, Va., then to Washington, D.C., July 5-29. Sheridan's Shenandoah Valley Campaign August 5-November 28. Third Battle of Winchester September 19. Fisher's