IHNC Hurricane Surge Barrier
Coastal Engineering Support Services
In August 2005, Hurricane Katrina devastated the United States Gulf Coast, centered on New Orleans. Katrina’s 5.5 meter (m) storm surge, the highest ever recorded in North America, funneled through the marshes east of New Orleans and overtopped the City’s flood control barrier walls and levees. 80% of the city was flooded, with some areas under 4.5 m of water. The storm left more than 1,800 deaths in its wake, destroyed or compromised over 800,000 housing units leaving thousands homeless, and caused USD 100 Billion in damages.
Hurricane Katrina led to the recognition of the need for significantly more resilient and integrated storm surge protection in the Greater New Orleans region. The federal government and U.S. Army Corps of Engineers (USACE) came together to replace the components of the previous hurricane protection system with an integrated, vastly improved, and world’s largest Hurricane and Storm Damage Risk Reduction System (HSDRRS).
The Inner Harbor Navigation Canal (IHNC) Hurricane Surge Barrier is the core of the HSDRRS, and New Orleans’ first line of defense against future hurricane storm surge. The IHNC Hurricane Surge Barrier consists of a 2.9 km, 7.9 m high barrier wall, three gates, and complete floodwall closure of the Mississippi River Gulf Outlet (MRGO).
The project’s massive scale and very-fast timeline required the close collaboration of over 250 engineers and scientists across the U.S. and Europe. Shaw E&I was awarded the surge barrier contract, with INCA leading the design effort as part of a joint venture with Ben C. Gerwick. AECOM (formerly ENSR) conducted extensive hydraulic physical modeling and analysis.
With extensive coastal engineering and marine construction experience in Louisiana, Lally was requested to support the Hurricane Protection System (HPS) through ENSR whom was subcontracted to INCA/Gerwick JV, the Engineer-of-Record for the main barrier, sector and swing gates, monolith walls and foundation, and scour protection for the barrier and gates.
Serving as Coastal Engineering Lead for AECOM/ENSR, among other tasks, Lally provided review and analysis of storm surge and wave modeling (coupled ADCIRC-STWAVE) results of a set of 152 hypothetical hurricanes, and developed 100-yr and 500-yr storm surge and wave conditions based on the numerical modeling results as input parameters for physical modeling of the IHNC HPS. This work served as the basis for developing the storm surge and wave condition parameters used to establish the structure heights, wave forces, and overtopping rates for the IHNC Hurricane Protection System.
Several reports, guidance, and data sets were applied as part of this task including foremost the Joint Coastal Surge (JCS) Analysis prepared by the Hurricane Protection Office (HPO), Interagency Performance Evaluation Task Force (IPET) report, Louisiana Coastal Protection and Restoration (LACPR) report, and latest U.S. Army Corps of Engineers coastal engineering design guidance.
Construction of the IHNC Hurricane Protection System began in late 2008, and 100-year level risk reduction was attained in May 2011, ahead of USACE’s goal for completion by the 2011 hurricane season.
Services Provided
Hurricane Hindcasting/Forecasting
Multiple Report and Guidance Review
Team Collaboration, Communications and Meetings
Analysis of Coupled (ADCIRC-STWAVE) Numerical Modeling Results
Development of 100-yr and 500-yr Storm Surge and Wave Design Parameters
Location
Coastal Louisiana, USA
Period
2007 – 2008
Costing in excess of USD $1.1 Billion, the IHNC Hurricane Surge Barrier is the largest single design-build civil works project ever undertaken by the USACE.