Grist points to postings from Dan Hill of City of Sound, who's been in a Brisbane suburb during the flooding. This post offers a nice summary, but the full piece from Hill is a very detailed look at the flood from the scene.
"If you need to drive to it, it might as well not exist: Walkability is important for quality of life, but in a disaster, it may be life and death. If you live in the urban sprawl, you're SOL if you can't get to a mall or downtown, because that's where all the necessary stuff is. Cities are more resilient when the stuff you need can be found on a small scale from neighborhood to neighborhood, not all clumped together in a megamall."