Morganza Spillway emergency use to divert additional water from the Mississippi River into the Morganza floodway, which merges downstream with the Atchafalaya floodway before entering the Gulf. Diversion of water from the Mississippi's main channel has the effect of lowering water level in the Mississippi downstream of the spillway, helping to relieve stress on levees and other flood control structures both upstream and down. Besides controlling flooding in a given event, the system is also designed to prevent the Mississippi River from permanently altering course down the Atchafalaya River, bypassing Baton Rouge and New Orleans. Water that passes the Morganza Spillway first
114th Ohio Infantry River Campaign April 26-May 22. Graham's Plantation May 5. Retreat to Morganza May 13–20. Mansura, or Marksville Prairie, May 16. Expedition to Atchafalaya May 30-June 6. Duty at Morganza until November 21. Moved to mouth of White River, Ark., November 21–26. Return to Morganza December 6. Expedition to Morgan's Ferry, Atchafalaya River, December 13–14. Moved to Kenner, La., January 8, 1865; thence to Barrancas, Fla., January 24. Campaign against Mobile, Ala., and its Defenses, March 20-April 12. March from Pensacola, Fla., to Blakely, Ala., March 20-April 2. Occupation of Canoe Station March 27. Siege of Spanish Fort and Fort Blakely