After Hurricane Karina, the Seabrook Floodgate Complex was constructed by the U.S. Army Corps of Engineers at a cost of $165 million. This complex operates in tandem with the Lake Borgne Surge Barrier to prevent storm surge from Lake Pontchartrain, during a 100-year storm event, from entering the Inner Harbor Navigation Canal (IHNC), as happened with Hurricane Katrina. The entire Seabrook Floodgate Complex is made of concrete and steel that spans 600 feet long at a height of 16 feet above sea level. It consists of a 95’ foot-wide navigable sector gate that has two pie-shaped gates weighing 220 tons a piece. In addition, it has two 50’ foot-wide vertical lift gates that can be lowered to also block the waters of Lake Pontchartrain. In the event of a storm, they are swung tightly closed, sealing the waterways from Lake Pontchartrain storm surge, thereby protecting the City of New Orleans from flooding.