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Corps To Shore Up Delta With Mississippi Mud

Corps To Shore Up Delta With Mississippi Mud

The Corps of Engineers is proposing to use up to 10 million cubic yards of Mississippi River mud from upriver every two years to shore up the mouth of the Mississippi River delta on the edge of the Gulf of Mexico, instead of depositing it in traditional areas reserved for dredged material, the St. Louis Post-Dispatch reported on June 19.

In a plan released in May, the Corps said it wanted to use mud from routine dredging operations along the river to build up the Plaquemines-Balize delta, also called the Bird’s Foot delta, in West Bay at the western edge of river’s mouth as it extends into the Gulf of Mexico. It was given that name because its alluvial spread looks like a bird’s foot from the air. It is sinking about an inch a year.

Coastal Louisiana has lost about 1,900 square miles of land since the 1930s. About 200 million tons of mud, silt and sand wash down the Mississippi River system every year, most of which ends up in the Gulf.

Moving the mud, as the Corps proposes to do, would be more expensive than simply letting it flow into the Gulf. The river has been configured by levees and other structures to deposit sediment further out into the Gulf than it used to, before river structures channeled its flow to make it faster, swifter, and more centered.

According to the Louisiana Web site of the Coastal Wetland Planning, Protection and Restoration Act, “For the last 1,200 years, sediment deposition has occurred primarily at the mouth of the Mississippi River’s Plaquemines-Balize delta, in the area defined as the Mississippi River Delta Basin. In this configuration, large volumes of sediment are required to create land area; consequently, land is being lost in this delta more rapidly than it is being created.”
Besides its importance to navigation, the Bird’s Foot delta is home to the Delta National Wildlife Refuge and the Pass a Loutre wildlife area. It also contains important oil and natural gas infrastructure.

Speaking of the Corps’ plan, Billy Nungesser, president of Plaquemines Parish and an outspoken national advocate for Louisiana coastal protection, told the Associated Press on June 19, “It’s what we needed to do for 20 years.” His parish extends along the lower river out into the Gulf.
The Corps’ plan has some detractors. The plan would close off a diversion that the Corps created in 2003 at West Bay to let the river’s silt-laden waters run through the gap to build up new land. State and local officials oppose closing the diversion.

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