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 Total federal cost: $576,355,000 Total non-federal cost: $310,345,000 The feasibility report was completed in March 2002. The Chief’s Report was signed on 23 August 2002. Preliminary Engineering and Design (PED) for the Houma Navigation Canal lock is ongoing and scheduled to be completed in December 2007. PED for the additional project features is also ongoing and scheduled to be completed in FY 08. A bill containing the authorization for Terrebonne's Morganza-to-the-Gulf hurricane protection system, a system of levees, floodgates and a lock on the Houma Navigation Canal, passed the U.S. Senate by an overwhelming margin today. The Senate voted 91