A mile-long surge barrier built near New Orleans in the wake of Hurricane Katrina has been awarded one of America’s highest civil engineering honours.
The Inner Harbour Navigation Canal Surge Barrier (IHNC), situated close to the iconic Louisiana city of New Orleans, has won the 2014 Outstanding Civil Engineering Achievement (OCEA) Award from the American Society of Civil Engineers.
The IHNC was authorised in 2006 by the US Congress just a year after Hurricane Katrina inflicted catastrophic damage upon New Orleans, with work on the project commencing in May 2009 and all major construction completed by June 2013. Design and construction work for the project were performed simultaneously in order to expedite the reduction of storm and flood-related risk in the region as swiftly as possible.
The project is considered to be one of the core measures of the Hurricane and Storm Damage Risk Reduction System developed by the US Army Corps of Engineers.
The surge barrier itself is essentially an extremely large flood wall measuring over a mile in length, running along a north-south axis from a point east of Michoud Canal on the north bank of the Gulf Intracoastal Waterway to a point south of the Bayou Bienvenue flood control structure.
The main barrier is comprised of 1,271 concrete piles measuring 1.7 metres across and 44 metres in length, each of which weighs 96 tonnes. These concrete piles are further buttressed by steel piles which are nearly 90 metres in length, and driven in at an angle of two horizontal to three vertical.
The anti-flooding measure will help protect those parts of the city most susceptible to storm surges emerging from the Gulf of Mexico and Lake Borgne, including New Orleans East, metro New Orleans, the 9th Ward and St. Bernard Parish.
Special features of the barrier include two navigable floodgates on the Gulf Intracoastal Waterway measuring over 45 metres in width, one of which employs a steel sector gate and the other a concrete barge swing gate; as well as a 17-metre wide navigable floodgate on Bayou Bienvenue fitted with a steel lift gate.
Engineers from Ben C. Gerwick Inc., which was responsible for the design of key portions of the surge barrier including the main structure and the floodgates, said the project was complex yet rewarding, particularly given the contribution it is expected to make to safeguarding key parts of the historic southern metropolis.
"It is personally gratifying to see this project built and to reflect on the impact it has on the entire region and on resiliency efforts in the United States," said Dr. Dale Berner, Gerwick vice president and technical director.