a once in decades flood doesn't make viable water catchment, average rainfall in the flinders basin averages less than 450mm, most years only 2- 300 mm punctuated by a 700mm plus year once a decade, this is what is called semi arid tropical climate, other places with this climate are usually sparsely populated pastoral and or subsistence farming, ie the Sahel and Botswana's Kalahari in Africa, the Chaco and sertao in South America, thar desert India https://en.m.wikipedia.org/wiki/Sertão https://en.m.wikipedia.org/wiki/Semi-arid_climate https://en.m.wikipedia.org/wiki/Sahel
