Atchafalaya Basin from the Mississippi, Red and Black rivers is diverted into the Atchafalaya at the Old River Control Structure. This flow diverts on average 25 percent of the Mississippi River flow down the Atchafalaya. In times of extreme flooding, the US Army Corps of Engineers may open the Morganza Spillway and other spillways to relieve pressure on levees and control structures along the Mississippi. On May 13, 2011, in the face of a rising Mississippi River that threatened to flood New Orleans and other heavily populated parts of Louisiana, the USACE ordered the Morganza Spillway opened for the first time since
Morganza to the Gulf benefits to the marshes and wetlands in the Terrebonne Basin. Safe Harbor: Fishermen will no longer have to leave the area in a storm event. A Reconnaissance Study for the Morganza, Louisiana to the Gulf of Mexico Hurricane Protection Project was authorized by Congress in 1992. Following completion of this report, the United States Congress authorized a Feasibility Study in the Energy and Water Development Appropriations Act of 1995 (Public Law 103-316). The Feasibility Study was completed in March 2002 and the Chief of Engineers letter was forwarded to the Secretary of the Army in August 2002 and supplemented in