Morganza Spillway weir, two sluice gates, seventeen scour indicators, and 125 gated openings which can allow up to of water to be diverted from the Mississippi River into the Atchafalaya Basin during major floods. The project was completed in 1954. A highway (Louisiana Route 1) and the Kansas City Southern Railway cross the structure The Corps of Engineers maintains the structures and, in times of flood, monitors their piers for scouring and stability. The Corps of Engineers has two 25-ton cranes used to lift and lower the flood gates. The cranes roll on special tracks next to the roadway, enabling the operators
2011 Mississippi River floods to open more gates on the spillway, the Corps studied four flooding scenarios, all of which assumed the Bonnet Carré Spillway near New Orleans would be concurrently operating at full capacity (100%). Following this analysis, which showed that extensive flooding 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 Corps of Engineers subsequently released a map showing the estimated times it would take the flood waters to reach the various