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MRGO Ecosystem Restoration Plan Feasibility Study

The Mississippi River Gulf Outlet (MRGO) Ecosystem Restoration Plan is being developed by the U.S. Army Corps of Engineers (USACE) as a supplement to the MRGO Deep-Draft De-Authorization Report. Currently the USACE is conducting a Feasibility Study that will result in a comprehensive ecosystem restoration plan to restore the Lake Borgne ecosystem and areas affected by the MRGO channel. This restoration plan is being developed in accordance with Section 7013 of the Water Resources Development Act (WRDA) of 2007. It is fully funded by the Federal government. The purpose of the study is to address systematic ecosystem restoration with consideration of measures to reduce or prevent damages from storm surge.

The study area includes portions of the Mississippi River Deltaic Plain within coastal southeast Louisiana and parts of southwest Mississippi. The study area encompasses approximately 3.8 million acres (over 6,000 square miles) of land and open water. In Louisiana, the study area includes the Upper, Middle, and Lower Lake Pontchartrain Sub-basins. In Mississippi, the study area includes the Western Mississippi Sound, its bordering wetlands, and Cat Island. These areas include portions of the Pearl River and the Coastal Stream hydrologic basins in Mississippi. The study area was developed to encompass the Lake Borgne ecosystem and areas that may have been affected by the MRGO navigation channel. The MRGO channel may have affected salinities as far west as Lake Maurepas. To the east, the MRGO channel was dredged through open water between the Breton and Grand Gossier Islands. The MRGO channel affected portions of the Lake Borgne ecosystem to the north and altered hydrology potentially as far south as the River Aux Chenes ridge.

Louisiana parishes in the study area include Ascension, Jefferson, Livingston, Orleans, Plaquemines, St. Bernard, St. Tammany, St. Charles, St. James, St. John the Baptist, and Tangipahoa parishes. Mississippi counties in the study area include Hancock and Harrison.

Map showing Ecosystem Restoration Plan Study Area
The study will evaluate the following issues:
  • Decreased fresh water, sediment and nutrient inputs
  • Hydrologic modifications
  • Saltwater intrusion
  • Wetland loss
  • Ridge habitat degradation and destruction
  • Retreating and eroding barrier islands
  • Bank and shoreline erosion
  • Human development susceptible to storm surge
  • Subsidence
  • Sea level rise
  • Altered circulation and water quality
  • Loss of shallow ponds
The study will look to investigate the following opportunities:
  • Freshwater, sediment and nutrient introduction
  • Wetland protection, restoration and protection
  • Shoreline Protection
  • Bank Stabilization
  • Ridge Protection and Restoration
  • Barrier Island Restoration and Protection
  • Water Control (gates, weirs, sills, plugs, fill areas, etc.)
  • Modifying MRGO project features
  • Use of native vegetation
  • Natural features for storm surge damage reduction
  • Modifications to authorized projects

To view a complete overview of the project, please view the fact sheet by clicking here.

In accordance with the National Environmental Policy Act (NEPA) of 1969, two public scoping meetings were held to introduce the study and seek public input. The first meeting was November 3, 2008, in Chalmette, Louisiana and the second was November 6, 2008, in Waveland, Mississippi. Materials and comments from these meetings are available by clicking the link below.

Input from the scoping meetings and interagency collaboration resulted in identifying 283 potential ecosystem restoration measures. Following the NEPA public scoping meetings, the study team screened these to 151 measures to be evaluated further. Some ecosystem restoration measures under consideration include freshwater diversions from the Mississippi River, water control structures, marsh creation using dredged material, shoreline protection, vegetative planting, swamp restoration/creation, ridge restoration, and barrier island restoration.

On April 2, 2009, the USACE hosted a Central Wetlands Forum which focused on one of the many study area subunits. The forum consisted of presentations and discussion sessions. For more information on the Central Wetlands Forum, click the link below.

To view the PowerPoint presentations, and discussion from the Central Wetlands forum, please click here.

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