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History of MRGO

The Mississippi River-Gulf Outlet (MRGO) was authorized by a March 29, 1956 Act of Congress (Public Law 84-455) to provide an emergency outlet from the Mississippi River in the interest of National defense and general commerce and as a safer and shorter route between the Port of New Orleans and the Gulf of Mexico. The act authorized construction of the MRGO Project in accordance with the recommendation of the Chief of Engineers contained in House Document No. 245, 82nd Congress. Public Law 84-455 reads in part:

“The existing project for Mississippi River, Baton Rouge to the Gulf of Mexico,
is hereby modified to provide for the Mississippi River-Gulf Outlet to be
prosecuted under the direction of the Secretary of the Army and supervision
of the Chief of Engineers, substantially in accordance with the
Chief of Engineers, contained in House Document Numbered 245,
Eighty-second congress, at an estimated cost of $88,000,000…”

The MRGO extends from the Inner Harbor Navigation Canal (IHNC) to the 38-foot depth contour in the Gulf of Mexico. Construction of the MRGO channel began in 1958 and was completed in 1968. All reaches of the MRGO navigation channel were authorized as a 36-foot deep, 500-foot bottom width waterway with the exception of the Bar Channel in the Gulf of Mexico which was authorized as a 38-foot deep, 600-foot bottom width waterway. The channel was dredged through shallow bays, coastal marshes and cypress swamps.

The Beginning

Ideas for a shorter navigation route to the Gulf of Mexico have been around for over 150 years. Corps records indicate a ship canal was proposed to Congress as far back as 1852. However, it wasn’t until the 1940’s when Port of New Orleans officials, as well as local and nationally elected officials, requested that the federal government build a shorter navigation route from New Orleans to the Gulf of Mexico. These leaders, along with the state government, envisioned two purposes for the channel – a safer, more efficient route to the Gulf and economic development spurred by expanded navigation capabilities in the vicinity of the new channel.

The vision included expanded port facilities and a new “Centroport,” a vast import/export complex complete with warehousing, a cargo airport, and road and rail connections. The Centroport was planned for the area that is now the north and south shores of Almonaster- Michoud area of Orleans and St. Bernard Parishes, as well as the area that encompasses the west side of the MRGO in St. Bernard Parish.

The Louisiana Legislature of 1944 officially empowered the governor “to aid and assist the federal government in obtaining and completing…." a tidewater canal from New Orleans to the Gulf on the eastern side of the Mississippi River. In March of 1958 construction of the channel began on the reach between the Industrial Canal and Paris Road. By February of 1960, dredging work was initiated to construct an interim channel of full depth and only half the width. In July of 1963 the interim channel was completed and on July 25, 1963 the first vessel traveled down the channel. By 1968, all dredging was completed on the channel, and it was operating at full capacity.

Hurricane Katrina

When Hurricane Katrina hit the Gulf Coast in August 2005, the parishes of Southeast Louisiana and counties of coastal Mississippi suffered widespread flooding and severe wind damage. Hurricane Katrina caused shoaling in the MRGO channel which limited its depth to 22 feet, and thus restricted deep-draft vessel access. Many deep-draft reliant businesses were severely impacted by storm damages and the limited navigability on the channel. Some companies chose to relocate while others were left to decide how to recover. Following Hurricane Katrina, in June 2006, the US Congress requested a plan for de-authorization of the MRGO (see Public Law 109-234).

MRGO Deep Draft De-Authorization

Congress directed the Secretary of the Army, acting through the Chief of Engineers, to plan for de-authorization of the MRGO from the Gulf Intracoastal Waterway (GIWW) to the Gulf of Mexico. The plan was to be developed in consultation with St. Bernard Parish, the State of Louisiana, and affected Federal Agencies. USACE started the de-authorization study in 2006. The goals of the study were to develop a comprehensive plan to de-authorize deep–draft navigation, evaluate any navigation functions that should be maintained, identify measures for hurricane and storm damage reduction, and to refine the plan to be fully integrated and consistent with the Louisiana Coastal Protection and Restoration Plan (LACPR) Final Report to Congress.

As directed by Congress, USACE submitted an interim report in December 2006 highlighting a viable plane to completely close the MRGO to all navigation from the GIWW to the Gulf. In January 2008 the Chief of Engineers signed a report recommending de-authorization of the channel, construction of a closure structure across the channel at Bayou La Loutre, and development of a supplemental report to provide an ecosystem restoration plan for the areas affected by the MRGO. On June 5, 2008 the Assistant Secretary of the Army for Civil Works forwarded the Final MRGO Deep-Draft De-authorization Report to Congress, officially de-authorizing the MRGO from the GIWW to the Gulf of Mexico as a federal navigation project.

MRGO Ecosystem Restoration

The MRGO Ecosystem Restoration Plan was developed by the U.S. Army Corps of Engineers as a supplement to the MRGO Deep-Draft Deauthorization Report to Congress. The comprehensive ecosystem restoration plan is aimed at the restoration and conservation of estuarine habitat areas affected by the MRGO navigation channel. Section 7013 of the Water Resources Development Act (WRDA) of 2007 authorized the development of the plan.

WRDA 2007 Section 7013 (P.L. 110-114 effective Nov. 8, 2007).

INCLUSIONS — At a minimum, the report … shall include:

  • a plan to physically modify the Mississippi River-Gulf Outlet and restore the areas affected by the navigation channel;
  • a plan to restore natural features of the ecosystem that will reduce or prevent damage from storm surge;
  • a plan to prevent the intrusion of saltwater into the waterway;
  • efforts to integrate the recommendations of the report with the [LCA] …and the [LACPR] analysis and design …; and 
  • consideration of— 
    • use of native vegetation; and 
    • diversions of fresh water to restore the Lake Borgne ecosystem.
  • Secretary to determine that project is cost-effective, environmentally acceptable, and technically feasible.

A feasibility study, fully funded by the Federal government, was completed on 28 September 2012. The plan includes projects to restore and protect approximately 57,472 acres of habitat.  Based on 2012 price levels, the Project First Cost is estimated at $3 billion. The total cost of the Monitoring and Adaptive Management Plan is $190 million, including costs for potential adaptive management actions. The operation, maintenance, repair, rehabilitation, and replacement (OMRR&R) costs for plan features are estimated at $427 million.  The OMRR&R costs would be a 100% non-Federal responsibility.

The plan includes the following:

  • 14,123 acres of fresh and intermediate marsh creation and restoration
  • 32,511 acres of brackish marsh creation and restoration
  • 466 acres of saline marsh creation and restoration
  • 10,318 acres of cypress swamp restoration
  • 54 acres of ridge habitat restoration
  • 71 miles of shoreline protection broken down by location:
    • 9.6 miles in Lake Pontchartrain
    • 31.2 miles in Lake Borgne
    • 24.4 miles along the MRGO
    • 5.8 miles of oyster reef restoration in the Biloxi Marsh

Implementation of the recommended ecosystem restoration plan requires the signing of a cost-share agreement between non-Federal sponsors, the State of Louisiana and the State of Mississippi, and the Corps of Engineers.  In addition, Congress must appropriate funds to design and build the projects in the plan.