The closure of the MRGO navigation channel is a direct result of the Deep-Draft De-authorization Report submitted by the USACE to Congress in June 2008. Submission of the report officially de-authorized the channel from the GIWW to the Gulf of Mexico and authorized the construction of a rock closure structure, removal of aids to navigation, and disposition of real estate easements.
In late July 2009, Pine Bluff Sand & Gravel Company from Pine Bluff, Arkansas completed placing the last loads of armor stone onto the Mississippi River Gulf Outlet rock closure structure. The rock structure was built 1,500 feet southeast of Bayou La Loutre in St. Bernard Parish. Final construction specs included the placement of approximately 352,000 tons of stone materials (approximately 126,000 tons of stone came from the south jetty at the end of the MRGO channel) to build the structure with a 12 foot crown, a 450 foot bottom width, and a top height of +8 feet NAVD 88. Channel bank tie-ins are 50 feet wide extending approximately 150 feet onto the south bank and 250 feet onto the north bank.