The U.S. Army Corps of Engineers is preparing to start a $200 million project to reinforce more than 80 miles of earthen levees in the New Orleans area.
In 2005, a tidal surge from Hurricane Katrina led to the failure of a number of earthen levees in the region, causing catastrophic flooding in Orleans and St. Bernard Parish. The Corps has since been repairing and upgrading the flood control system in the past decade with better pump stations and stronger levees.
To further minimize the impacts of erosion, the Corps will reinforce the levees with a combination of Bermuda sod and a high performance turf reinforcement mats (HPRTMs).
Soheila Holley, Senior Project Manager for the Corps of Engineers, says armoring can augment existing levees materials to provide additional resilience.
"As the grass roots grow through the open space of HPRTM, roots become entwined within the turf reinforced mat. The interlocking can enhance the resistance against hydraulic and sheer forces," says Holley.
Articulated concrete mats will be used in areas where heavy traffic is anticipated on the crown of the levee. Holley says the material is relatively maintenance-free aside from mowing the grass. Occasional inspections will identify dead patches of grass or ripped material to maintain the integrity of the armor.
"We have a procedure in place in case of tear or damage to the HPRTM and it will be repaired or replaced," says Holley.
The Corps is breaking up the project and awarding bids in small segments. The first part is a section of levees north of Destrehan in St. Charles Parish which is being installed by Circle LLC for $5.9 million.
The armoring of all levees should be completed by 2015 or 2016.