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
69th Indiana Infantry Regiment until October. Western Louisiana "Teche" Campaign October 3-November 30. Ordered to Algiers December 13, then moved to Texas December 18. Duty at Matagorda Bay and Indianola until February 1864, and at Matagorda Island until April 19. Moved to New Orleans, thence to Alexandria, La., April 19–27. Red River Campaign April 27-May 22. Actions at Alexandria April 29 and May 2 to 9. Graham's Plantation May 5. Retreat to Morganza May 13–20. Duty at Morganza until December. Expedition to the Atchafalaya May 30-June 6. Expedition to mouth of White River and St. Charles, Ark., September 13–20. Moved to Dauphin Island, Mobile