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 2011 event) had been opened by the Corps of Engineers. The Corps estimated the flow rate at . However, on May 25, new estimates from the U.S. Geologic Survey (USGS) described a much higher rate of , resulting in the closure of 3 bays by May 26, and additional closures by May 29, bringing the total to 11 bays with an estimated diversion rate of . The Corps continued to evaluate the flow and close additional bays as appropriate. By June 6, the number of open gates had been reduced to seven, and by June 8, only two gates were