ArmorMax stands up to Hurricane Gustav and IKE case study
When Hurricane Katrina made landfall on August 29, 2005 it caused devastating flood damage to large portions of southeastern Louisiana—but it was not the only hurricane to hit the area that year. Hurricane Rita made landfall in late September, causing catastrophic tidal inundation to the community of Lafitte as it passed south of Jefferson Parish, Louisiana. One of the many levees that needed rehabilitation was the Pen Levee. The LADOTD and the Lafitte Levee Board made the decision to incorporate the ArmorMax anchored reinforced vegetation system into the project design. The Decamp Street Levee which intersects the Pen Levee was also armored with ArmorMax. Not only did the ArmorMax system offer a cost-effective approach to armoring the levees, but the innovative approach offered immediate protection from erosion and scour forces caused by wave overtopping and storm surge similar to what happened from Katrina. When wave overtopping occurs, the levee soil surface is subject to severe erosion and scour that can lead to breaches causing catastrophic failure. The ArmorMax system is an engineered armoring solution that provides permanent erosion protection to the levee resisting soil movement and uplift that can occur.
The design for the 1.8 mile (2.90 Km) long Pen Levee included the use of the ArmorMax system to armor the levee crest (top) and down the backside slope to the Borrow canal. The project was installed in two phases. Phase I installation was completed in July 2007 with the ArmorMax system installed starting 5 feet (1.52 m) from the sheet pile wall to 18 feet (5.49 m) across the levee crest. Phase II installation started in May 2008 and started where Phase I ended 25 feet (7.62 m) down the back side of the slope. Prior to installation the levee was prepared by “scalping” the vegetation with a mower and then back-dragging it to fill in any depressions and remove any obstructions. The HPTRM component was then installed and secured with Type 2 earth percussion anchors in a checkerboard grid pattern at five feet (1.52 m) centers. The earth percussion anchors act as a tie-down mechanism with 500 lbs (227 Kgs) of maximum pull-out strength for greater factors of safety. The ArmorMax installation in both phases was complete in 6 weeks each time versus typical installation of rock riprap which could take 4 to 5 months. The DeCamp Street Levee was an additional 1300 feet (396.24 m) of ArmorMax installed from the front toe of the levee over the crest and down to the backside toe.
In September 2008, the Pen Levee was subject to heavy rain from Hurricane Gustav and a 12-foot (3.66 m) storm surge from Hurricane Ike. The ArmorMax system held its ground during the severe overtopping and storm conditions resisting erosion and scour.