NOLA 2023 First Day
After a rainy morning at the Woodlands Conservancy, the team went for a quick levee failure tour in the lower 9th ward. We stopped right in front of the rebuilt levee where a barge had bumped into the wall, causing the flood waters & storm surge from the Mississippi River to burst into homes, down streets, and destroy almost everything in the first few streets along the levee. During this time, the team heard the story of how in 1927, levees in New Orleans were bombed to save the city. Unfortunately, those affected by this bombing were mostly poor, black residents, some of whom were forced off their properties at gun point. Because of this past/generational trauma, it was believed by some that the government had bombed the levee walls again to deliberately destroy the lower 9th ward during Hurricane Katrina.
In typical Dr A fashion however, he quickly squashed this conspiracy with scientific backing by showing aerial photos of the levee before, during, & after the Hurricane Katrina, all photos showing a barge which had moved from the river, into a house in the lower 9th. There is a lot more that went wrong during Katrina, including but not limited to way in which the levee was constructed.
In its basic form, the levee was not created to withstand the force that overtook it. The Army Corps of Engineers (The Corps) built the levee system in 1985 to replace surge barriers, but they were not built tall enough, nor were they properly braced to stop the force of Katrina. The Corps had originally believed I-walls to be structurally sound, yet they failed to account for several factors: variability in soil strength, wall deformation (which opened a water-filled gap on the flood side) & critical water pressures beneath the levees.
The Corps went back to the drawing board after Katrina & redesigned the floodwall to become a T-wall. In addition, they raised the height of the floodwall to the proper dimensions & the walls were completed in 2013, 8 years after Hurricane Katrina. The better design of the floodwalls, seen below, have mostly kept up so far, but still require regular maintenance when gaps are noticed between the floodwall & the levee.
Although it may not look like it in the picture below, the new floodwall is between 15 & 18 feet high, with some areas reaching above 30 feet. It’s support pylons reach down to 100 (& even 200 feet in some places) into the ground throughout the 130 mile ring levee system around New Orleans & are built to hold out a storm surge of 30+ feet.
After a long, cold, rainy, day, the team hopped back into the vans, much more appreciative of their raincoats & warm boots.