Office of Mineral Resources

Contract let to create land in south La.

Mississippi River sediment will restore wetlands just below Venice

NEW ORLEANS – Great Lakes Dredge & Dock Co., Oak Brook, Ill., has been awarded a contract to begin a precedent-setting project to restore south Louisiana wetlands through diversion of Mississippi River sediment and water.

Under the $3.6 million contract, awarded Aug. 22, Great Lakes’ big, red dredge California will cut through the river’s low, narrow bank six miles below Venice. This would send sediment and water into West Bay at 20,000 cubic feet per second.

The U.S. Army Corps of Engineers and the Louisiana Department of Natural Resources will share the cost 85 percent federal and 15 percent local.

Construction is to begin in September. It will be the first phase of the $22.3 million West Bay Sediment Diversion Project to restore 10,000 acres of wetlands over 20 years.

The project will be the first to restore coastal Louisiana through the large-scale diversion of sediments and fresh water directly from the Mississippi River into coastal marshes. No structure or gates will be built to operate the diversion.

“This project will harness the natural land-building power of the river and mimic the natural processes that formed coastal Louisiana,” said Gregory Miller, the Corps’ project manager. “Once this area was coastal wetland, but now it is shallow, open water.”

An interim channel will be dug first, designed to limit flow to 20,000 cubic feet per second (cfs) at average river stage. If experience proves it feasible, the channel would be enlarged to discharge 50,000 cfs into West Bay.

The interim diversion will be closely monitored before the larger channel is cut. A relatively small portion of riverbank and adjacent wetlands will be excavated to build the diversion channel. The project will be built under the federal Coastal Wetlands, Planning, Protection and Restoration Act, also known as the Breaux Act.