Old River Control Structure of 1973 almost caused the control structure to fail. Integrity of the Old River Control Structure, the nearby Morganza Spillway, and other levees in the area is essential to prevent such a diversion. Jeff Masters of "Weather Underground" noted that failure of that complex "would be a serious blow to the U.S. economy." The present Old River Control Structure was completed in 1964 and expanded in 1990. The first two floodgates are the Low Sill Control Structure, which regulates routine flow in the waterway, and the Overbank Control Structure, in use only when the Mississippi exceeds its banks. A navigation
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