The majority of work was completed by 2011 when the area met the 100-year-flood standard.

The system withstood Hurricane Gustav in 2008 and Hurricane Isaac in 2012 without any overtopping or breaches.

Given the slow-moving nature of Hurricane Isaac in 2012, Park says that had the Inner Harbor Navigation Canal Surge Barrier at Lake Borgne and the Seabrook Floodgate Complex at Lake Pontchartrain not been in place, the area would have suffered from Isaac’s surge.

But there is still more work to be done. In addition to doing interior drainage work, the Corps has contracted with PCCP Constructors, a joint venture comprising Kiewit Louisiana South Co., Traylor Bros. Inc. and the M.R. Pittman group, to build three permanent canal closures and pumps in three New Orleans locations. Park says that work will cost about $700 million when completed by the 2017 hurricane season.

Work was delayed by months of bid protest and litigation in 2011 and 2012.

Additionally, the Corps is spending about $34 million to armor 80 miles of earthen levee with high-performance grass and sod on the protected side to mitigate erosion in case the levees are overtopped.

When complete, the system is expected to last through 2057.

Unsettling Levees

But as early as next year, some of the region’s levees could sink below the 100-year protection standard because of settling.

On Aug. 27, the Southeast Louisiana Flood Protection Authority-East is scheduled to hire at least three firms to begin the work of raising some of the post-Katrina levees.

The authority is planning to raise as many as 20 miles of levees along the Lake Pontchartrain waterfront in Jefferson Parish and in eastern New Orleans.

While the Corps oversaw the design of the floodwalls, the responsibility for levee lifts was left to the regional authorities.

“The Corps always knew that by 2016-2017, the levees were going to be at or below the design level,” Turner says.

The levee authority is moving early on the levee lifts to complete them before the Corps armors those sections of the levees. Having to rearmor the levees would double the cost of the lifts, Turner says. 

The authority expects the cost for the levee lifts will be between $20 million and $37 million.  Turner says the authority expects the lifts will last the region through at least 2025 or 2030.