In late August 2005, Hurricane Katrina ravaged Louisiana leaving around 1800 dead in its wake. A week ago, Hurricane #Ida made its way through Louisiana again but this time the official death toll was just 1 person, although the continuing rains led to over 40 deaths in the Northeast, thousands of miles away.
What really changed there? Sure, Ida was a hurricane Category 4 and Katrina was Category 3, but those numbers don’t really mean much when calculating the impact of hurricanes. Katrina brought in winds at 125 mph while Ida had winds at 150 mph, but the size of the hurricane varies greatly – Katrina had hurricane-force winds up to 110 miles from its center whereas #Ida stretched to only 45 miles. The answer lies in a simple but effective technique that man has used since medieval times – Levees! Since Katrina, the US government has spent up to 15 billion dollars on building and maintaining these new levies.
What are levies? Levies are natural or manmade embankments that are higher than the water level and keep rivers and lakes out. If you look at the river you can see that the banks of the river are slightly elevated as compared to the highest point of the water level along the banks. This is naturally formed as the river keeps depositing sediment along the banks, similarly, man has also deposited clay and other earth materials to solidify these levies. They work in a two-part process, the first part is there are you prevent the water from breaching the levee, and the second part is where you pump back any water that spills over back into the water body. The famous windmills in Holland do just that, they pump any excess water that makes it into the marshlands back into the river. They even went one step further in Holland and created artificial rivers that can help drain the water faster and take it away from cities and towns.
In New Orleans, there are two levee systems in place, one along the Mississippi River and the other along Lake Pontchartrain. The old levee systems failed during Hurricane Katrina as they only prepared for storms that have been seen in the past. The new levee system is designed for hurricanes that occur once in 200 years and also prepare for future intensification of storms. Hurricane #Ida was the biggest field test for the new levee system, the system has been implemented and tested for storm surges, but nothing can really prepare it for when nature decides to wreak havoc.
While Katrina brought storm surge flooding of up to 28 feet above the sea level and went over the walls of the levees, Ida wasn’t that bad and mainly brought destruction through its winds. The city of New Orleans lies 3 meters below sea level on the southern coast of Lake Pontchartrain and is further protected by a complex system of levees, pumps, canals, and floodwalls run by the US Army Corps of Engineers protect it from regular flooding. Over time, as the land slips lower, the levees also get lower with them and that requires constant maintenance and upkeep. Back in 2005, the levee system was maintained by a bunch of contractors and private companies leaving holes in responsibility and maintenance. The new system brings with it responsibility and ownership that may just be the reason it protects lives for years to come.
Since you guys can’t drive your Chevy to the levy, here’s bringing your internet explorer to it instead!
Fount of wisdom, insufferable know it all, make it go away are just some of the phrases used to define Melwyn. When he is not at his Consulting job, he spends his time reading about technology and current affairs.