Morganza Spillway the Corps had also opened 330 of the 350 bays of the Bonnet Carré Spillway located near New Orleans. Morganza Spillway The Morganza Spillway or Morganza Control Structure is a flood-control structure in the U.S. state of Louisiana along the western bank of the Lower Mississippi River at river mile 280, near Morganza in Pointe Coupee Parish. The spillway stands between the Mississippi and the Morganza Floodway, which leads to the Atchafalaya Basin and the Atchafalaya River in south-central Louisiana. Its purpose is to divert water from the Mississippi River during major flood events by flooding the Atchafalaya Basin, including
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