Morganza Spillway stilling basin, and substantial flooding occurred in the Atchafalaya Basin. After the 1973 flood, the structure was restored to its original condition. The issue of opening the gates to keep the Mississippi in its current place was next raised in May 1983. Although the gates were not opened, Louisiana Highway 1 running across the spillway was closed, and the Corps of Engineers built a ring dike and put a blanket of earth across a section of the spillway to contain water pouring underneath it. During the Great Mississippi and Missouri Rivers Flood in 1993, officials decided to leave the gates
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,