NEW ORLEANS – The U.S. Army Corps of Engineers, Team New Orleans, achieved a major Hurricane and Storm Damage Risk Reduction System milestone today with the placement of the Gulf Intracoastal Waterway (GIWW) sector gate leafs in the closed position at the Inner Harbor Navigation Canal (IHNC)-Lake Borgne Surge Barrier. With this final closure, the entire IHNC (also known locally as the Industrial Canal)-GIWW corridor, which was heavily damaged in the 2005 hurricane season, can now defend against a storm surge event that has a one percent chance of occurring in any given year, or a 100-year storm surge event.
In addition to the 150-foot-wide GIWW sector gate, the $1.1 billion IHNC-Lake Borgne Surge Barrier project consists of a 150-foot-wide barge gate, also at the GIWW, a 56-foot-wide vertical lift gate at Bayou Bienvenue, floodwall tie-ins, and a braced concrete wall across the Mississippi River Gulf Outlet (MRGO) and Golden Triangle Marsh. The surge barrier, which rises 26 feet above the waterline, is located just west of Lake Borgne and about 12 miles east of downtown New Orleans, or about 8 miles east of the Lower Ninth Ward.
Last week, the Corps finished the floodwall and installed the Norfolk Southern Railroad gate south of the Senator Ted Hickey Bridge and west of the Seabrook Floodgate Complex, thus effectively blocking 100-year storm surge generated in Lake Pontchartrain from entering the north end of the IHNC. In addition to these features, a cofferdam in which the $165 million Seabrook Floodgate Complex will be built and floodwalls on the east and west sides will provide the 100-year risk reduction for the 2011 hurricane season.
“The IHNC-Lake Borgne Surge Barrier and the Seabrook Floodgate Complex will now serve as the first lines of defense against storm surge entering the IHNC-GIWW corridor,” said Col. Robert Sinkler, commander of the Corps’ Hurricane Protection Office. “These structures will effectively remove about 33 miles of interior levees and floodwalls as the first line of defense and work in tandem to reduce storm surge risk to New Orleans East, metro New Orleans, the Ninth Ward, Gentilly and St. Bernard Parish.”
Although the 100-year level of risk reduction will be achieved at the IHNC-GIWW corridor for this year’s hurricane season, construction will continue at the IHNC-Lake Borgne Surge Barrier and the Seabrook Floodgate Complex into early 2012. Remaining work at the Surge Barrier includes outfitting the gates with mechanical and electrical controls, building the control houses and safe house, constructing the access ramps, installing the guide walls for the gates, installing the Bayou Bienvenue steel lift towers and bridge, and other ancillary items. At Seabrook, crews this summer will begin constructing the 95-foot-wide sector gate and the two 50-foot-wide vertical lift gates that constitute the floodgate complex.
“Our teammates, contractors, partners and stakeholders have worked hard to provide the 100-year level of risk reduction for the IHNC-GIWW corridor,” said Col. Sinkler. “Without our strong inter-agency team, it would have taken more than a decade to provide 100-year risk reduction for the corridor.”
Images of the IHNC-Lake Borgne Surge Barrier can be found here: http://www.flickr.com/photos/teamneworleans/sets/72157622078053978/.
Images of the Seabrook Floodgate Complex can be found here: http://www.flickr.com/photos/teamneworleans/sets/72157623709300046/.
High resolution images are available upon request