On August 26th, 2005, the world’s eyes turned to New Orleans as it became the site of the country’s deadliest natural disaster in decades and the planet’s most expensive one on record. While the immense scale of Hurricane Katrina — a Category 5 hurricane with 174 mile-per-hour winds that directly hit a major urban center — is to blame for the storm’s devastation, the municipal, state, and federal governments also deserve much blame for their faulty preparation and response.
When people talk about Katrina’s damage, they don’t mention the size of the storm nearly as much as the shoddiness of the infrastructure. “The levees failed” remained Louisiana’s most common curse for years.
The levee breakage claimed 1,833 lives and cost $125 billion in damage.
Eighty percent of the city was underwater, and the federal government’s response was delayed by three days. Homeless families languished in the Superdome, if they weren’t still starving on their rooftops, waiting to be rescued. People asked, can this really be happening? In this country?
Of the 250,000 people that fled the New Orleans before, during, or after Hurricane Katrina, less than 150,000 have returned, to a city much different from what they once knew. Slowly, the city has rebuilt itself over the past 10 years, undergoing a social and cultural transformation, and in some neighborhoods, a revitalization. But who’s to say that New Orleans will not get swept away again?
What Went Wrong With Hurricane Katrina?
New Orleans was used to weathering hurricanes every year, given that it sits below sea level in the Mississippi River Delta on an only-mildly-secluded bay of the Gulf of Mexico. But before 2005, there hadn’t been a big enough hurricane to motivate New Orleans to update its 1960s-era levees that had been thrown in place to protect the city from mild storm surges. In many parts of the city, water protection was porous or completely nonexistent.
Research increasingly demonstrates how years – or decades – long periods of low hurricane frequency are followed by periods of high frequency: the last decades of the 20th century were one of these low periods, which ended around the turn of the century. Research also shows how, despite these peaks and trenches in hurricane frequency, on average we experience one additional hurricane per year every 30 years, and that the overall energy output of each hurricane is increasing.
In short, Hurricane Katrina was an exceptionally high-energy hurricane during a high-frequency period after a lull in annual hurricane rates. It completely caught New Orleans off guard. The city had settled into a false sense of security that silenced the few climate scientists who warned of disaster.
Hurricane Katrina is considered to be at least a 200-year storm. This does not mean that a storm of its size will only happen every 200 years; it means that every year, there is a 1-in-200 chance of another Katrina.
How Not To Build Levees
Survivors of Katrina often describe how the initial storm brought intense winds and storm surges, overtopped many levees and barriers, and flooded much of the city. Then the storm passed, and though it had left a trail of destruction and stranded or killed many people, most assumed that the worst had passed. But then, many awoke the next day to find much more flooding, which trapped more people in their homes or buildings and claimed even more lives.
In simple terms, each phase of flooding represents a different engineering flaw with the levees. When Hurricane Katrina first hit, it brought with it a storm surge, basically a wall of water, about 20 feet high. Most of New Orleans’s levees were not built high enough to accommodate anywhere close to a 20-foot storm surge. So, these levees were overtopped. Some were also too weak to resist the force of the storm surge, and they were breached on impact or soon after.
The second phase of flooding was largely caused by the unstable ground on which these levees were built. Once certain areas had flooded but others were kept dry by their own, intact levees, the ground water supporting those levees became soaked through, and after a while, gave way. These levees either cracked, collapsed, or leaned until they were overtopped. Many more New Orleans neighborhoods were lost this way.
Another problem was the faulty system of water pumps. These pumps were supposed to drain flooded canals and waterways, but most of them failed due to the high volume of water. Therefore, the water was left where it was for days, causing the ground to grow unstable, damaging levees and buildings alike.
10 Years and $14.5 Billion Later…
The Army Corps of Engineers, who was originally responsible for building Louisiana’s levees, has since sunk $14.5 billion dollars in a new system of pumps and levees to protect New Orleans from inevitable hurricanes in the future. The system is now in place, and it is designed to withstand 152 different hurricane scenarios, including a 100-year storm (though, as Katrina proved, that will not always be enough).
133 miles of concrete now protect the city. This includes the two-mile-wide, 26-feet-tall Lake Borgne Surge Barrier, which alone costs $1.1 billion, and many other levees, flood gates, and pump stations—including the world’s largest pump station, which can fill an Olympic-size pool in three seconds. New Orleans now has perhaps the most sophisticated storm protection infrastructure on the planet.
An additional $50 billion that the city is owed by the oil company BP for settlement on its 2010 oil spill will be diverted towards natural wetland restoration, since these wetlands act as natural storm buffers. However, those wetlands are currently being depleted faster than they can be restored.
Ideally, the city would be able to raise its new levees even higher, or strengthen them even more, to account for a 200-year or 500-year storm. Another goal is to raise the buildings themselves and to zone out construction for at-risk areas. The science, foresight, and infrastructure is much more advanced now than it was before Katrina—and New Orleans residents are much more willing to be cautious.
Would you feel safe living in New Orleans with its new hurricane defense system? Share your thoughts!