The Central Wetlands Unit (CWU) consists of 29,140 acres of wetland stretching from Orleans Parish into St. Bernard Parish bordering the former Mississippi River Gulf Outlet (MRGO), the Hurricane and Storm Damage Risk Reduction System (HSDRRS) Levee, and the 40 Arpent Levee and Canal.

The CWU was once a thriving swamp that provided natural storm surge protection for densely populated communities in Orleans and St. Bernard parishes. However, impacts from the leveeing of the Mississippi River.

Construction of manmade canals, logging, and construction of the MRGO affected hydrology and salinity in the area and transformed swaths of the wetlands to open water.

The MRGO is formerly a 76-mile shipping channel between the Mississippi River and the Gulf of Mexico that exposed some 31 miles of wetlands to saltwater during its 41 years in existence and has been blamed for the deadly flooding of the Lower Ninth Ward during Hurricane Katrina. The outlet was later closed and attention turned to ecosystem restoration projects to protect and rebuild area wetlands. Hydrologic restoration was recommended as a first step to restoring the CWU.

Multiple navigation, pipeline, and logging canals with spoil banks that create impoundments on the exist in the CWU. These spoil banks restrict tidal and riverine exchange and cause the stranding of salt water that enters the impoundments during storm events. Hydrologic restoration efforts planned for this project are to gap or cut these spoil banks to allow water to flow freely into and out of the canals and adjacent wetlands, carrying with it nutrients and sediment to nourish the area. Additionally, the project includes nearly eight acres of wetland creation in currently open water areas.

Beyond providing storm and flood protection, restoring the CWU will serve as a highly visible and tangible demonstration of the benefits of wetlands restoration due to its proximity to New Orleans.