A feature of Fraser Island is the many – dozens – of small lakes set among the sand dunes. They are formed in three ways:
* window lakes are, rather literally, windows on the water table, depressions between dunes low enough to intercept the water table;
* perched lakes are above the water table, formed when (plant?) material builds up in a depression and forms an impermeable barrier to water; and
* lakes may form when a sand dune blows across a stream bed, blocking flow.
Lake Wabby is one of the last type. (That’s two people at the base of the dune, and the Pacific Ocean in the background.)