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 was expected in the Atchafalaya Basin regardless of the choice made regarding the Morganza Spillway, the Corps decided to start the 2011 diversion by opening the spillway a bit less than described in scenario 1a (21%, not 25%) The Governor of Louisiana, Bobby Jindal, had meanwhile sent a letter on May 4, 2011, to Robert Gates, the United States Secretary of Defense, requesting that the National Guard be deployed under Title 32 of the United States Code status to respond to record water levels in Louisiana, where there was "a significant probability that the U.S. Army Corps of Engineers [would]