Hurricane Katrina demonstrated the need for a comprehensive risk reduction system for the greater New Orleans area. Following Katrina, Congress authorized and funded the construction of the 100-year level risk reduction system, known as the Hurricane and Storm Damage Risk Reduction System (HSDRRS). The HSDRRS includes five parishes (Orleans, Jefferson, St. Bernard, St. Charles, and Plaquemines) and consists of 350 miles of levees and floodwalls; 73 non-Federal pumping stations; 3 canal closure structures with pumps; and 4 gated outlets.
The Greater New Orleans HSDRRS provides the 100-year level of risk reduction against tropical events and related rainfall and storm surges. The $14 billion system includes the construction or improvement of 133 miles of perimeter risk reduction features, such as levees, floodwalls, floodgates and pump stations. HSDRRS was designed for a 50-year project life and the design accounted for sea level rise, subsidence and increased storm frequency throughout that time frame. Construction of the system also included resiliency features, such as the armoring of the backside of levees and floodwalls to prevent scour in the event of wave overtopping.
The hurricane protection system built through the Greater New Orleans HSDRRS is stronger and more resilient than it has ever been in the area’s history, and the new system is capable of defending against a tropical event that has a 1% chance of occurring any given year.
The Corps also supports the multiple lines of defense strategy for reducing risk, which includes the restoration of Louisiana’s coastal areas. Coastal habitats provide an important buffer between open water and structural protection like the HSDRRS.