Old River Control Structure of 1973 almost caused the control structure to fail. Integrity of the Old River Control Structure, the nearby Morganza Spillway, and other levees in the area is essential to prevent such a diversion. Jeff Masters of "Weather Underground" noted that failure of that complex "would be a serious blow to the U.S. economy." The present Old River Control Structure was completed in 1964 and expanded in 1990. The first two floodgates are the Low Sill Control Structure, which regulates routine flow in the waterway, and the Overbank Control Structure, in use only when the Mississippi exceeds its banks. A navigation
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