It would be difficult to quantify the number of people that were affected by Katrina and that could be said to have 'survived' Katrina. In general, everyone in the world that didn't die during Hurricane Katrina can be said to have survived it.
Hurricane Katrina affected not only people, but the whole environment. People lost millions of dollars to try to fix/repair this mess. Many lost their homes, jobs, shelter, everything. It is such a tragic thing to go through.