2011 Mississippi River floods and this connection implies persistence of dry conditions for the next 2 to 3 years. During the 2011 floods, concerns were raised that the Mississippi might divert its main channel into the Atchafalaya Basin if the Old River Control Structure, the Morganza Spillway, or nearby levees failed, or into Lake Pontchartrain if the Bonnet Carré Spillway or adjacent levees failed. Jeff Masters of the "Weather Underground" noted that failure of the Old River Control Structure "would be a serious blow to the U.S. economy, and the great Mississippi flood of 2011 will give [this structure] its most severe test ever."
Morganza Spillway still open. All bays were closed on July 7, 2011. The Corps had estimated that it would take opening one-fourth of the spillway’s 125 bays — or 31 bays — to control the flow of the river through Baton Rouge in response to a forecast crest of anticipated on Tuesday, May 17, 2011, which must remain below of water per second through Baton Rouge to ensure the integrity of the levee system. Since Morganza never operated above , the flooding in the Atchafalaya Basin was considerably lower than had been anticipated during the initial estimates of . By May 29,