|Inner Harbor Navigation Canal Surge Barrier
Official Project Name
Inner Harbor Navigation Canal Surge Barrier (IHNC)
A surge barrier, similar to a floodwall but much larger, will be constructed near the confluence of
the Gulf Intracoastal Waterway (GIWW) and the Mississippi River Gulf Outlet (MRGO),
generally running north-south from a point just east of Michoud Canal on the north bank of the
GIWW and just south of the existing Bayou Bienvenue flood control structure. Navigation gates
will be constructed where the barrier crosses the GIWW and Bayou Bienvenue to reduce
the risk of storm surge coming from Lake Borgne and/or the Gulf of Mexico. Another
navigation gate is planned for the Seabrook vicinity where the IHNC meets Lake
Pontchartrain to block storm surge from entering the IHNC from the lake.
The Inner Harbor Navigation Canal (IHNC) surge barrier is a new feature, authorized by Congress in 2006, that will reduce the risk of storm damage to some of the region’s most vulnerable areas – New Orleans East, metro New Orleans, the 9th Ward, and St. Bernard Parish. This project aims to protect these areas from storm surge coming from the Gulf of Mexico and Lake Borgne.
An aerial view of the IHNC-Lake Borgne Surge Barrier, with the barge and sector gates in the closed position.
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The project consists of a bypass barge gate and a flood control sector gate at the GIWW, a vertical lift gate at Bayou
Bienvenue, a braced concrete barrier wall across the MRGO and the Golden Triangle Marsh, and floodwalls on the
north and south ends that tie into the risk reduction system in Orleans Parish and St. Bernard Parish, respectively.
In April 2008, the U.S. Army Corps of Engineers awarded the construction contract to The Shaw Group, making this
the largest design-build civil works project in Corps history.
In December 2008, the Corps held a ground-breaking ceremony to mark the start of test pile-driving. Construction of
the barrier floodwall, which will be 10,000 feet (1.8 miles) in length, began on May 9, 2009, and crews are working
around the clock to meet the 1 June 2011 deadline. As of October 2010, the barrier wall and floodwall tie-ins are
substantially complete. In addition, construction continues at the three gates. The barge gate is currently open to all
marine traffic along the GIWW while a cofferdam closes off the sector gate portion of the channel.
Benefit to the Community & Project Features
Benefit to the Community
Following Hurricane Katrina, an Interagency Performance Evaluation Task Force (IPET) was convened to find scientific and engineering answers to questions regarding the functioning of the New Orleans levee system during the storm. IPET was established by the Chief of the U.S. Army Corps of Engineers and includes more than 150 nationally recognized experts from more than 50 different organizations (eight federal, state and local government agencies; 25 universities; and 23 private sector firms). According to the IPET report, Hurricane Katrina caused four levee breaches along the IHNC, three due to overtopping and one due to foundation failure. Read the report here: https://ipet.wes.army.mil.
The breaches in the IHNC floodwalls caused by Hurricane Katrina have been repaired and the greater New Orleans area flood risk reduction system is now stronger than it has ever been.
In summary, the IHNC surge barrier project allows the Corps to achieve a level of 100-year risk reduction by 2011 for some of the region’s areas most vulnerable to flooding.
• Concrete floodwall with navigation gates at Bayou Bienvenue and the GIWW
• Navigation gate at Seabrook vicinity
• Marsh enhancement with dredged organic material – As organic material is dredged from waterways in preparation for new construction, it will be deposited in nearby wetlands habitat to enhance environmental conditions.
Public Law 109-234, Emergency Supplemental Appropriations Act for Defense, the Global War on Terror, and Hurricane Recovery, 2006 (4th supplemental)
The U.S. Army Corps of Engineers is committed to providing a 100-year level risk reduction for southeast Louisiana in 2011 through its Hurricane and Storm Damage Risk Reduction System (HSDRRS). The HSDRRS seeks to upgrade existing flood protection features (such as levees and floodwalls) and introduce new features authorized by Congress and deemed necessary to complete the system.