In the years since Hurricane Katrina, the Corps of Engineers has been constructing and bolstering 350 miles of levees, floodwalls, barriers, gates and other structures as part of the Greater New Orleans Hurricane and Storm Damage Risk Reduction System (HSDRRS), which stretches across five parishes and includes much of the original Lake Pontchartrain and Vicinity Basin, as well as the West Bank and Vicinity Basin on the West Bank of the Mississippi River.