Well That's What I Heard

Popular Mechanics does yoemans work to debunk many of the myths of Hurricane Katrina.

Later in the series PM proposes solutions to the defective levees as well as explains the genesis of the inadequate design of the floodwalls.

After Betsy, the plan was expanded to include gates on two of the four drainage canals that slice into the city from Pontchartrain (two of which breached their floodwalls after Katrina). But, environmental groups objected to the impact that the Pontchartrain floodgates might have on wildlife and wetlands. The Sewer and Water Board of New Orleans vetoed gates on the canals. So the Corps instead built higher levees and floodwalls.

Read the whole thing.

T-walls incorporate double foundations for stability and concrete skirts
to prevent scouring of earthen levees. DIAGRAM BY BLANDDESIGNS