Lake Wabby is relatively close to the ocean side of Fraser Island and unlike the other lakes, it supports several varieties of fish. It is known as both a window lake and a barrage lake. Window lakes form when the ground level falls below the water table. Barrage lakes form when a sand blow blocks the waters of a natural spring. This phenomenon is easy to see at Lake Wabby. On one side it's deep green waters are bordered by a giant sand dune that is slowly moving into the lake. In a century or so, the sand dune's inexorable march westward across Fraser Island will see it completely swallow the lake.