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
67th Indiana Infantry Regiment 10-May 22. Advance from Franklin to Alexandria March 14–26. Battle of Sabine Cross Roads April 8. Monett's Ferry, Cane River Crossing, April 23. Constructing dam at Alexandria April 30-May 10. Retreat to Morganza May 13–20. At Morganza and Baton Rouge until August. Operations in Mobile Bay against Forts Gaines and Morgan August 2–23. Siege and surrender of Fort Gaines August 3–8. Capture of Fort Morgan August 23. Duty at Morganza until December. Expedition to mouth of White River November 12–20. The regiment lost a total of 249 men during service; 1 officer and 52 enlisted men killed or mortally wounded,