In the wake of Hurricane Katrina, which insurance companies are predicting will ultimately be the most damaging storm ever to hit the United States, New Orleans faces what may be the largest unwatering project in the history of North America.

The hurricane downed the city’s flood control system, including a network of pumps capable of moving 35 billion gallons of water per day and a complex system of levees, which was designed to protect the low-lying area from floodwater, but failed under the onslaught of Katrina after she struck the Gulf Coast on the morning of Aug. 29 as a Category 4 hurricane.

The unwatering effort is being led by the U.S. Army Corps of Engineers (www.usace.army.mil), which has made a series of strategic breaches in the levees surrounding New Orleans and, as of Sept. 25, was operating 54 portable auxiliary pumps with a total capacity of 2,080 CFS. According to Russ Novak, director of research at ARC Advisory Group (www.arcweb.com), since most of the water bodies surrounding New Orleans are tidal, the Army Corps of Engineers was able to drain a lot of the floodwater from the city by actually creating holes in the levees, some of which were already badly damaged by the storm. In the early part of the unwatering process, the water in many areas of New Orleans was higher than it was in the water bodies themselves. So by creating strategic holes in the levees, floodwaters could be drained back out of the city. As the water level outside of the city rose, the holes were sealed back up, allowing the portable and existing stormwater pumps to continue the unwatering.

The unwatering effort suffered a setback over the weekend, when another storm, Hurricane Rita, struck the Gulf Coast, overwhelming the already weakened levee system and allowing floodwaters to flow back into parts of New Orleans. Prior to Rita, the Army Corps of Engineers was estimating the unwatering of New Orleans to be complete by mid-October, but now the effort will likely take longer.

Following Hurricane Katrina and the subsequent flooding of New Orleans, many questioned how a major American city could fall victim to such a huge disaster. Questions have been raised about the quality of the city’s flood control system, and reports have surfaced that funding requests by the Corps of Engineers to bolster levees in New Orleans were severely undercut. According to the Corps of Engineers, the Bush Administration’s fiscal year 2006 budget request for the four main New Orleans flood control projects [West Bank, Southeast Louisiana, Lake Pontchartrain, and New Orleans Venice] was $41.5 million, significantly less than the Corps of Engineers’ capability figure for the projects of $142.7 million. However, the Corps of Engineers officially denied that the failure of New Orleans’s flood control system was a funding issue, noting that project capability figures are not akin to budget requests and are rarely funded in full because they assume unlimited resources.

ARC”s Novak believes Hurricane Katrina would have been difficult to overcome even with stronger flood protection. “Nobody’s ever built a containment system for a Category 4 hurricane with a 30-foot storm surge,” says Novak. “And even if you did, how would you test it?” Once the levees broke, he says the drainage pumps were pretty much useless because they weren’t designed to operate under water. In addition, he says power outages prevented the pumps from returning to operation for some time after the storm. Backup diesel-powered generators weren’t an option either, as they were buried in water as well.

When the flood control system in New Orleans is redesigned, Novak says most of the focus will likely be on the levees. Still, he says it’s impossible to know whether the system will be designed to withstand a hurricane as strong as Katrina, and, even if it is, whether it will be designed to that strength in all areas or just in strategic locations. Novak says the ultimate plan for rebuilding the flood control system will likely be fueled by politics, as the government’s slow response in the aftermath of the hurricane has made the effort more of a social issue than a technological one.

Bjorn Von Euler, director of communications for ITT Industries (www.itt.com), a manufacturer of pump technology, which provided a number of the systems used by New Orleans to provide flood relief, believes the rebuilding effort will show the influence of Katrina. “I would expect that when we look at the rebuilding of New Orleans, a lot of lessons learned about infrastructure will be part of the solutions,” says Von Euler. ITT is one of many companies that has offered to support the unwatering effort in New Orleans, providing nine submersible diesel pumps capable of 20,000 GPM each. In addition, it has offered reverse-osmosis and desalinization systems to help with decontamination.

The Corps of Engineers has contracted with several firms to assist it in the unwatering of New Orleans. These contractors are dealing directly with companies like ITT to get the equipment they need to facilitate the recovery and rebuilding. Many companies have made equipment available to the recovery effort at no cost or severely discounted prices. Von Euler says all of the hard work by the Corps of Engineers, the contractors supporting the project, and the charity of manufacturers is making the situation in New Orleans better moment by moment. “It’s getting more organized, less confused, and we’re seeing some positive results,” says Von Euler. “It’s a much more positive situation than it was a couple of days ago.”

— Flow Control Staff