With no native vegetation in the surrounding land to transpire ground water, scenes like this dead lake are commonplace. Dry land salinity is not by any means restricted to Western Australia, it is just more spectacular in WA than it usually is in the other states.
Humans have been destroying good land by clearing and over-irrigating it for thousands of years, possibly tens of thousands of years. A great deal of the Middle East where civilisation began was originally rich, fertile farming country: now it is desert. Here in Australia where the continent is older and the soils less fertile, the land is correspondingly less able to resist abuse and the process of destruction is faster.