Pumps in Action: Hurricane Protection

Seven years after Hurricane Katrina devastated the New Orleans metro area, Hurricane Isaac made landfall on Aug. 28, 2012, as a Category 1 hurricane just southwest of the mouth of the Mississippi River with sustained winds of 80 mph. It was only 95 miles southeast of New Orleans. The most significant problem with Isaac was its slow movement, and as it crept north, it dumped enormous amounts of rain. Its slow movement and sustained strength long after landfall made it another potentially devastating storm. The situation, again, looked grim for the Big Easy. However, a stalling Isaac would not match Katrina’s flooding or damage because lessons were learned during and after Katrina, and changes and improvements had been made during the seven years since the city lay in ruin. Also, a massive, multimillion-dollar pump station, built on the Intracoastal Waterway, helped drain the Crescent City before extensive flooding could occur. Station operators on the ground watched as wind and rain that would have devastated in 2005 gushed from pump stations around the city and along its waterways, removing millions of gallons of water. In 2005, the system—levees, canals and pumps stations—was not able to handle Katrina’s onslaught. According to Rene Poche, public affairs officer with the Army Corps of Engineers—New Orleans District, prior to Hurricane Katrina, the Hurricane Protection System was a system in name only. “The Corps incorporated the lessons learned from Katrina by using the best science and engineering available to construct the best risk reduction system in the area’s history,” Poche said.

In addition to increasing levee and floodwall elevations to meet 100-year storm surge requirements, the Corps used stronger construction methods, such as:

• More robust T-wall design for floodwalls
• Stricter clay requirements for the earthen levees
• Deep-soil mixing for greater stability

Perhaps the greatest change is that now the system is a perimeter system. With the construction of the system’s large closure structures—including the Intracoastal Waterway West Closure Complex (WCC), Inner Harbor Navigation Canal (IHNC) Lake Borgne Surge Barrier, the Seabrook Floodgate Complex and closures on the three outfall canals—the system is designed to prevent the surge from entering the interior parts of the greater New Orleans area. Levees and floodwalls—such as those along the IHNC, Algiers Canal and the outfall canals—that were once first lines of defense during Katrina have been relegated to secondary risk reduction features. “This perimeter system allows the team of Corps and local authorities to fight surge at the source, away from major populated areas,” Poche said. As the storm approached, the team for the WCC had its action plan. The operating team—consisting of personnel from the Corps of Engineers, the State of Louisiana Coastal Protection and Restoration Authority (CPRA), Gulf Intracoastal Constructors (Kiewit and Traylor Brothers), MR Pittman Group, Prime Controls and Louisiana Machinery—assembled on the site at 6 p.m. on Monday, Aug. 27 to begin preparations for the storm, including pre-storm protocol. Fuel was brought in to “top off” the supply. “At 8:40 a.m., the gate closure sequence began, and at 9:38 a.m., operation of the pumps began. All the components performed as expected throughout the storm,” Poche explained. The storm surge varied at different locations. At the WCC, it reached a maximum of more than 5 feet at 9:47 a.m. on Aug. 30. At the height of the storm, all 11 WCC pumps were operating and pumping at a rate of 515,401,920 gallons per hour. Fortunately, the WCC performed as expected and served its intended function. Constructing the WCC was accomplished by Gulf Intracoastal Constructors, a joint venture of Kiewit Corp. and Traylor Brothers. Some key subcontractors were:

• MR Pittman Group (pump station)
• Louisiana Machinery/Caterpillar, Lufkin, Fairbanks Morse, Prime Controls (engines, gears, pumps and controls)
• Boh Brothers (404c floodwall)
• Bertucci (dredging and rock)
• Phylway (levees)
• King Fab (gates)

For more details on the WCC construction, read “The Gulf Intracoastal Waterway West Closure Complex to Protect New Orleans” at www.pump-zone.com.