The History Channel (THC) series "Cities of the Underworld" episode "New York" (2007) has a segment on the World Trade Center and the need for and creation of the "bathtub". (the final segment)

It shows some historical video and talks about what happened when the towers collapsed into the bathtub.

It might have some valuable information in there. I didn't catch anything offhand, but it should be viewed more than once and scanned for info by multiple people to ensure nothing is missed.

I don't see where it can be viewed online. I also don't see it playing again. You can order the DVD, but it's pricey.