Hurricane preparedness in New Orleans

New Orleans, Louisiana sits between (and below) the Mississippi River and Lake Pontchartrain.
Vertical cross-section of New Orleans, showing maximum levee height of 23 feet.

Hurricane preparedness in New Orleans has been an issue since the city's early settlement because of its location.

New Orleans was built on a marsh. Unlike the first two centuries of its existence, today a little under half of the modern city sits below sea level. The city is surrounded by the Mississippi River, Lake Pontchartrain to the north, and Lake Borgne on the east.

The earliest-settled parts of New Orleans and surrounding communities are above sea level. However, flooding was long a threat, from the periodic high waters of the Mississippi and from more occasional severe tropical storms which pushed the waters of Lake Pontchartrain into settled areas. Construction of the levees along the River began soon after the city was founded, and more extensive river levees were built as the city grew. These earthen barriers were erected to prevent damage caused by seasonal Mississippi River flooding. The Lake Pontchartrain shore was mostly undeveloped swamp, and only small levees were built there in the 19th century.