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Location
The Orleans Landbridge is the stretch of land and marsh separating Lake Pontchartrain from Lake Borgne in Orleans Parish. The project is along 8.7 miles of the northwestern shoreline of Lake Borgne stretching from Bayou Bienvenue on the western edge to Alligator Point in the east.
Issue Addressed
The eventual destruction of the landbridge due to subsidence, high wave energy, and the resulting shoreline retreat (averaging 7.7 feet per year) could result in Lake Pontchartrain—and thus New Orleans and Northshore communitites—being subjected to increased storm surge damage.
Project Goals
The project uses 217,000 tons of concrete recycled from the dismantled 1-10 twin span bridges. Shoreline stabilization will prevent the loss of 110 acres of marsh and minimize shoreline retreat. The project also protects the nation’s largest urban wildlife refuge, the 23,000-acre Bayou Sauvage National Wildlife Refuge.
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- After Hurricane Katrina, the State Dept. of Transportation and Development replaced the damaged I-10 twin spans with a new, safer structure. CPRA is recycling the concrete into shoreline revetments.
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- 658 spans and 586 substructures from the old twin spans will yield a total of 86,807 cubic yards of crushed concrete weighing approximately 217,000 tons.
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- The concrete is crushed into aggregate and loaded into thousands of Geogrid Marine Mattresses. The mattresses will be placed as revetment along the shoreline and will have strategic gaps to help reduce habitat impact and maintain flow within the interior marsh.
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- The aggregate-filled mattresses will be placed along the crest of the shoreline and descend along the slope with the bottom end buried in the lakebed and anchored against slippage.
Project Type:
Shoreline Protection
Project Information:
Project number: PO-36