The plan is divided into three projects, each of which will take about 18 months to complete, and are expected to be built in succession:
-- The first project would use limestone rock to armor the shoreline of Lake Borgne at Shell Beach, with material dredged from within the lake brought in to rebuild wetlands between the shoreline and the MR-GO.
-- Next, the corps would use rock to protect the lake shoreline in two stretches at Bayous Dupre and Bienvenue.
-- The final project would fill in open water areas on the northwest side of the "golden triangle, " an area of wetlands sandwiched between the MR-GO and the Gulf Intracoastal Waterway. That project would be completed last to coordinate with the construction of a storm-surge barrier across the triangle that is part of the corps's "100-year" levee improvements, designed to protect the New Orleans area from surge caused by hurricanes with a 1 percent chance of occurring in any year.
The corps announced Thursday that it had authorized Shaw Environmental and Infrastructure Inc. to prepare for construction of the barrier and levee project, clearing the way for it to begin staging equipment and supplies in the area.
Some land acquisition in the footprint of the barrier project must still be completed, corps officials said.
The corps also has embarked on a broader study of how to restore wetlands and land features lost to erosion caused by ships and barges using the MR-GO and by construction of the ill-fated shipping channel itself.
That study was authorized by the 2007 Water Resources Development Act, but Congress must still approve and appropriate money for any projects it recommends.
The 2007 water act also ordered deauthorization of the MR-GO as a navigation channel. A $24.7 million rock dike is to be built across the channel at Bayou la Loutre in St. Bernard Parish by June 1, 2009.
The corps already has spent about $5 million of the $75 million appropriated by Congress in 2005 for a small wetlands-restoration project and some armoring along the MR-GO.
This brings us one step closer to realizing our goal of reducing risk from storm surge for the citizens of the greater New Orleans area,” said Lt. Col. Victor Zillmer, resident engineer for the project. “Mobilization efforts include staging equipment, conducting surveys, fabricating steel batter piles and spun cast piles used to anchor the barrier.”
The next steps include real estate acquisition and then the start of construction, which could begin in November with dredging, the corps said.
“Dredging will take about two months, and then we’ll begin driving piles to support the surge barrier,” Zillmer said.
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The surge barrier will extend from the Michoud floodwall north of the Gulf Intracoastal Waterway to the levee on the west side of the Mississippi River-Gulf Outlet just south of the existing Bayou Bienvenue control structure. The barrier will include a 150-foot surge gate and a 150-foot barge gate to facilitate navigation along the GIWW.
“The system will also feature a new navigable flood control sector gate at Bayou Bienvenue, a braced concrete wall across the MRGO and a concrete floodwall across the marsh between these waterways,” said Rick Kendrick, the corp's Hurricane Protection Office chief of program execution. The existing Bayou Bienvenue flood control structure would be maintained in its existing condition and could continue to be used to regulate high tides.
The corps expects to complete the project in 2011.
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