Lake Carnegie (Western Australia)

Lake Carnegie is an ephemeral lake in Western Australia. It fills with water only during very rare periods of significant rainfall, such as during the huge 1900 floods and in numerous recent tropical wet seasons when the monsoon and tropical cyclones have been moved south by recent climate change. In dry years, it is reduced to a muddy marsh.

Water entering the lake, unlike in more easterly playas of the Australian arid zone, does not come from well-defined river channels since the soils of the region are so weathered - lacking tectonic or glacial activity since the Carboniferous ice ages - that sediment is completely absent and the terrain so flat that only the most unweatherable rocks remain on the surface and well-defined river channels cannot form especially since the extreme age of the soils and consequent hihg rooting density of native flora limits runoff to an extreme extent.