Mississippi River floods in the largest volume of water to flow down the Mississippi since the Great Mississippi Flood of 1927. Both the Bonnet Carre Spillway and the Morganza Spillway were employed. The Bonnet Carre was fully opened between April 7 and June 14 for a record 75 days. The 1973 flood was the first time the Morganza Spillway was opened: from April 19 through June 13. In April, 225 bays of the Bonnet Carre Spillway were opened for 15 days, the shortest duration on record. Reserve, Louisiana had a crest of on April 14. the 8th highest on record. April, all 350
Morganza Spillway still open. All bays were closed on July 7, 2011. The Corps had estimated that it would take opening one-fourth of the spillway’s 125 bays — or 31 bays — to control the flow of the river through Baton Rouge in response to a forecast crest of anticipated on Tuesday, May 17, 2011, which must remain below of water per second through Baton Rouge to ensure the integrity of the levee system. Since Morganza never operated above , the flooding in the Atchafalaya Basin was considerably lower than had been anticipated during the initial estimates of . By May 29,