Old River Control Structure channel and lock were also part of the original facility design. Subsequent expansion created what is now known as the Old River Control Complex, when the Auxiliary Structure, which became operational in 1986, was added to reduce pressure on the original floodgates after extensive damage caused by the flood of 1973. The Sidney A. Murray Jr. Hydroelectric Station, completed in 1990, also provides an additional measure of control at the site. Water from the Mississippi is normally diverted into the Atchafalaya Basin only at Old River, where floodgates are routinely used to redirect the Mississippi's flow into the Atchafalaya River
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