Mississippi River back from the river, it is normally dry on both sides. Even if it failed at the crest during a severe flood, the flood waters would have to erode to normal water levels before the Mississippi could permanently jump channel at this location. During the 2011 floods, the Corps of Engineers opened the Morganza Spillway to 1/4 of its capacity to allow 150,000 ft/sec of water to flood the Morganza and Atchafalaya floodways and continue directly to the Gulf of Mexico, bypassing Baton Rouge and New Orleans. In addition to reducing the Mississippi River crest downstream, this diversion reduced the
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