New Orleans Airport: Flood-Prone Or Safe?

New Orleans is a city that is particularly vulnerable to flooding. Situated between the Gulf Coast and the Mississippi River, almost half of the area is below sea level, and the region is prone to heavy storms and hurricanes. In 2005, Hurricane Katrina caused massive damage across New Orleans, with around 80% of the city flooding. More recently, in May 2019, a flash flood warning was issued for the city, and in September 2024, Hurricane Francine triggered a flash flood emergency, causing water rescues and road closures. Given the city's history of flooding, it is important to consider the resilience of its airport to such events.

Hurricane Francine caused flooding in New Orleans in 2024

Hurricane Francine caused severe flooding in New Orleans in 2024. The Category 2 hurricane made landfall south of Morgan City, Louisiana, on September 11, 2024, with sustained winds of around 100 mph. Although it weakened into a minimal hurricane by the evening, it still brought torrential rains and powerful winds to the region.

The hurricane triggered a flash flood emergency in New Orleans as intense rainfall led to water rescues and road closures. Nearly 10 million residents of Louisiana and neighbouring states, including Mississippi, Alabama, and Florida, were under flood watches ahead of Francine's arrival. The storm's impact was felt across New Orleans, with businesses and homes affected by the rising waters.

New Orleans International Airport recorded 7.33 inches of rainfall, making it the city's second-wettest September day on record and the ninth-wettest day overall since 1946. The airport's floodgates had to be closed to protect the city from the storm surge. Motorists were warned not to drive through flooded roads, as most flood deaths occur in vehicles.

The National Weather Service issued warnings, urging residents to move to higher ground due to the life-threatening situation. The storm's impact extended beyond Louisiana, with nearly 300,000 electrical outages reported in the initial hours and powerful gusts hitting several towns. Louisiana Governor Jeff Landry declared a state of emergency, and President Joe Biden authorised a disaster declaration to enable FEMA to provide direct assistance to affected parishes.

New Orleans' defences against flooding

New Orleans is particularly vulnerable to flooding due to its geographical location between the Gulf of Mexico and Lake Pontchartrain. The city's flood defences include 350 miles of levees and barriers, as well as floodgates and marshlands that act as natural barriers against the sea.

In 2005, Hurricane Katrina caused over 50 failures of the levees and flood walls, flooding 80% of New Orleans and causing severe damage to over 200,000 homes and businesses, and resulting in over 1,000 deaths. This event exposed flaws in the design and construction of the city's flood defences.

In response to the devastation caused by Hurricane Katrina, the United States Army Corps of Engineers (USACE) commissioned engineering company Royal HaskoningDHV to help overhaul the city's flood defences. The project involved redesigning and rebuilding the Greater New Orleans Hurricane and Storm Damage Risk Reduction System, including the city's network of floodgates and barriers. Engineers used computer modelling to understand the shortcomings of the previous system and to design improvements.

One of the issues identified was the erosion of the back slopes of the levees, particularly where weaker materials like soil were used. To address this, project engineers designed structures to support and strengthen the levees and transition points. They also advised on how to rebuild and strengthen the marshlands of the Louisiana coast, enhancing their effectiveness as a natural barrier.

In addition to physical defences, Royal HaskoningDHV developed a Levee Information Management System to optimise operational processes and the Hurricane Surge Atlas, which helps emergency managers assess the expected storm surge levels of approaching hurricanes.

The impact of flooding on New Orleans' infrastructure

New Orleans is situated between the Gulf Coast and the Mississippi River, and almost half of the area is below sea level. The region is prone to heavy storms, with hurricanes building up in the nearby Gulf of Mexico annually. These storms often cause flooding, as well as damage and loss of life. In 2024, Hurricane Francine triggered a flash flood emergency in New Orleans, with meteorologists reporting between 6 and 8 inches of rain. This led to the second-wettest September day on record for the city, with 7.33 inches of rainfall.

The city has extensive defences against flooding, with 350 miles of floodgates and levees. Levees are embankments or walls, usually made of earth, that run parallel to a river and hold back rising waters during storms. However, in 2005, Hurricane Katrina caused massive damage to New Orleans, largely due to the failure of the city's flood barrier system. The storm overwhelmed the local flood protections, and about 80% of New Orleans was flooded, with some areas under 15 feet (4.6 m) of water. The Lower Ninth Ward was one of the hardest-hit areas, with the majority of properties completely destroyed.

Following Hurricane Katrina, independent investigators found that the levees and floodgates had failed due to system design and construction flaws. The US Army Corps of Engineers (USACE) commissioned engineering companies to help overhaul and redesign the city's flood defences. The new system, known as the Greater New Orleans Hurricane and Storm Damage Risk Reduction System, involved collecting data on the performance of the levees and using computer modelling to design improvements. Engineers now believe that New Orleans is protected against hurricane and storm events for the foreseeable future.

In addition to the levees and floodgates, the city of New Orleans also has pumps that help to drain floodwaters. After Hurricane Katrina, the city had to fix its water pumps to clear the floodwaters. While some areas have fully rebounded, others still have storm damage or have been left uninhabited. Overall, the city has bounced back well since 2005, and its defences continue to be upgraded to protect against future flooding events.

The Lower Ninth Ward was one of the worst-hit areas

New Orleans has a history of flooding due to its low-lying topography, with much of the city sitting just above sea level, and parts of it below. The city's flatness has often been likened to a bowl, but some believe it is more like a waffle, with pockets of low ground that easily fill with water during heavy rainfall.

During Katrina, the Lower Ninth Ward was inundated with floodwaters, with many residents having to be rescued from their homes. The hurricane also caused widespread power outages, leaving many people without electricity, water, or food. The floodwaters did not recede quickly, and the area continued to experience challenges long after the hurricane had passed. The impact of Katrina on the Lower Ninth Ward was so significant that it led to a substantial population decline in the years following the hurricane. Census data from 2010 revealed a notable decrease in residents, with many choosing to leave the area due to the extensive damage and flooding.

The impact of flooding in the Lower Ninth Ward was not limited to physical damage and population decline. The social and economic fabric of the community was also significantly affected. The neighbourhood had a high proportion of public housing complexes, which were among the worst-hit areas during the hurricane. The loss of housing stock and the subsequent displacement of residents disrupted the sense of community and social cohesion in the area. Additionally, the flooding exacerbated existing social and economic inequalities, as the neighbourhood was already facing challenges such as poverty and a lack of investment.

The vulnerability of the Lower Ninth Ward to flooding has raised questions about the effectiveness of flood protection measures in New Orleans. After Hurricane Betsy in 1965, there was a push for improved flood control, which led to the construction of a levee system around a larger geographic area, including previous marshland and swamp. However, the impact of Katrina on the Lower Ninth Ward highlighted the limitations of these measures and the need for more robust and comprehensive flood protection.

The French Quarter escaped flooding

The French Quarter, founded in 1718, was the only New Orleans for about 70 years, from its inception until around 1788. It was built on a relatively high point, about 14 feet above sea level, with a ridge of land connecting it to Bayou Sauvage, Lake Pontchartrain, and the Gulf of Mexico. This made it less vulnerable to flooding compared to the surrounding wetlands and swamps.

The French Quarter has faced several major floods in its history. In 1816, a levee break in Kenner brought water up to Chartres Street. In 1849, the Sauve crevasse flooded 220 squares and displaced 12,000 people. In 1871, the great crevasse at Bonnet Carre sent a massive amount of water into Lake Pontchartrain, and when a north wind blew, the Hagan Avenue levee broke, flooding the city. Despite these challenges, New Orleans, and the French Quarter, always rose again.

The French Quarter's location was strategically chosen by Bienville, near French plantations, and it was considered "just about perfect" by François Marie Perrin Du Lac, a French observer. Du Lac noted that if the city had been located on higher ground, it would be too far from the sea, and moving it downstream would increase its vulnerability to flooding.

When Hurricane Katrina hit in 2015, the French Quarter's higher location spared it from flooding, while other areas of New Orleans were not so fortunate. The French Quarter's resilience in the face of flooding throughout its history is a testament to the city's enduring spirit.

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