I specifically wrote about the damage to the Lower Ninth Ward when the levee collapsed and a wall of water, carrying a barge, suddenly flooded into the neighborhood. Though there was little water pressure, perhaps 20 or 30 psi, the volume of flow and the fact that it applied that pressure over the full face of a building, resulted in sufficient force to destroy the buildings and leave only the concrete slab, if that.
I was part of a survey group that went through the area after the Hurricane and made several hours of video which I summarized in a short review. On the occasion of the anniversary it is, perhaps appropriate to put this up. This comes with the sound, as I recorded it at the time. It begins in the Lower Ninth Ward, and then goes back to the start of the trip.
After visiting one of the smaller breaches in the city, we drove down the Delta to the point where the boats went out to service the rigs, and where the hurricane had come ashore as a more powerful force. Yet it was the water damage that was prevalent, as can be seen from those buildings that had survived because they were on stilts and thus out of the storm water.
We then returned to the Lower Ninth Ward, mainly near the breach. This is where the barge went through the breach, obviously at some speed, since it was carried beyond the main channel of the flow and then dropped onto the school bus as the flood waters passed further into the ward.
As I mentioned there are hundreds of photos and hours of video that we shot, but this gives some sense of the disaster.