Atchafalaya Basin from the Mississippi, Red and Black rivers is diverted into the Atchafalaya at the Old River Control Structure. This flow diverts on average 25 percent of the Mississippi River flow down the Atchafalaya. In times of extreme flooding, the US Army Corps of Engineers may open the Morganza Spillway and other spillways to relieve pressure on levees and control structures along the Mississippi. On May 13, 2011, in the face of a rising Mississippi River that threatened to flood New Orleans and other heavily populated parts of Louisiana, the USACE ordered the Morganza Spillway opened for the first time since
Battery A, 1st Missouri Light Artillery on Jackson, Miss., July 5–10. Siege of Jackson July 10–17. Ordered to New Orleans, La., August 6, then to Carrollton, and duty there until October. Western Louisiana Campaign October 3-November 30. Bayou Cortableaux October 21. Carrion Crow Bayou November 3. At New Iberia until December 17. Moved to New Orleans, then to Madisonville January 7, 1864. Red River Campaign May 2–20. Moved to Alexandria, La., May 2. Attached to Army of the West and Department of the Missouri. Retreat to Morganza May 13–20. Expedition from Morganza to the Atchafalaya River May 30-June 6. Moved to Carrollton June. Duty there and