2011 Mississippi River floods feet per second just upstream from the Old River Control Structure. The US Army Corps of Engineers refers to this design goal as Project Flood. the expected flow will be on the high side, but still within that maximum capacity, assuming everything works as expected. On May 14, a single floodgate of the Morganza Spillway was opened in order to divert of water from the Mississippi River to the Atchafalaya Basin. This diversion was deemed necessary to protect levees and prevent major flooding in Baton Rouge and New Orleans, with the tradeoff of exacerbating flooding in the Atchafalaya Basin, and
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