Building for the future

Well ... what do they know that we don't? In Brisbane, Queensland, they're building a new Riverwalk. The last one was washed away in the 2011 floods. This one will be built to survive a one-in-2000-year flood. So, if Australia has only been under white settlement (with written records) for 250 years or so, how can they possibly know what a 2000 year flood event looks like? If it's because they have already seen one, is a Riverwalk that will withstand another one necessary? Or do one-in-2000-year events happen more regularly these days?